[PATCH v2 4/9] tools/kapi: Add kernel API specification extraction tool

Sasha Levin
2026-03-22T12:10:45Z

The kapi tool extracts and displays kernel API specifications.

Signed-off-by: Sasha Levin <sashal@kernel.org>
---
Documentation/dev-tools/kernel-api-spec.rst | 15 +-
tools/kapi/.gitignore | 4 +
tools/kapi/Cargo.toml | 19 +
tools/kapi/src/extractor/debugfs.rs | 578 ++++++
tools/kapi/src/extractor/kerneldoc_parser.rs | 1555 +++++++++++++++++
tools/kapi/src/extractor/mod.rs | 461 +++++
tools/kapi/src/extractor/source_parser.rs | 408 +++++
.../src/extractor/vmlinux/binary_utils.rs | 508 ++++++
.../src/extractor/vmlinux/magic_finder.rs | 115 ++
tools/kapi/src/extractor/vmlinux/mod.rs | 844 +++++++++
tools/kapi/src/formatter/json.rs | 720 ++++++++
tools/kapi/src/formatter/mod.rs | 142 ++
tools/kapi/src/formatter/plain.rs | 707 ++++++++
tools/kapi/src/formatter/rst.rs | 850 +++++++++
tools/kapi/src/main.rs | 122 ++
15 files changed, 7039 insertions(+), 9 deletions(-)
create mode 100644 tools/kapi/.gitignore
create mode 100644 tools/kapi/Cargo.toml
create mode 100644 tools/kapi/src/extractor/debugfs.rs
create mode 100644 tools/kapi/src/extractor/kerneldoc_parser.rs
create mode 100644 tools/kapi/src/extractor/mod.rs
create mode 100644 tools/kapi/src/extractor/source_parser.rs
create mode 100644 tools/kapi/src/extractor/vmlinux/binary_utils.rs
create mode 100644 tools/kapi/src/extractor/vmlinux/magic_finder.rs
create mode 100644 tools/kapi/src/extractor/vmlinux/mod.rs
create mode 100644 tools/kapi/src/formatter/json.rs
create mode 100644 tools/kapi/src/formatter/mod.rs
create mode 100644 tools/kapi/src/formatter/plain.rs
create mode 100644 tools/kapi/src/formatter/rst.rs
create mode 100644 tools/kapi/src/main.rs

diff --git a/Documentation/dev-tools/kernel-api-spec.rst b/Documentation/dev-tools/kernel-api-spec.rst
index c4ff7d61045c8..aed8a400ec53a 100644
--- a/Documentation/dev-tools/kernel-api-spec.rst
+++ b/Documentation/dev-tools/kernel-api-spec.rst
@@ -30,7 +30,9 @@ The framework aims to:
common programming errors during development and testing.

3. **Support Tooling**: Export API specifications in machine-readable formats for
- use by static analyzers, documentation generators, and development tools.
+ use by static analyzers, documentation generators, and development tools. The
+ ``kapi`` tool (see `The kapi Tool`_) provides comprehensive extraction and
+ formatting capabilities.

4. **Formalize Contracts**: Explicitly document API contracts including parameter
constraints, execution contexts, locking requirements, and side effects.
@@ -454,15 +456,10 @@ Modern IDEs can use the specification data for:
- Context validation
- Error code documentation

-Testing Framework
------------------
-
-The framework includes test helpers::
+Example IDE integration::

- #ifdef CONFIG_KAPI_TESTING
- /* Verify API behaves according to specification */
- kapi_test_api("kmalloc", test_cases);
- #endif
+ # Generate IDE completion data
+ $ kapi --format json > .vscode/kernel-apis.json

Best Practices
==============
diff --git a/tools/kapi/.gitignore b/tools/kapi/.gitignore
new file mode 100644
index 0000000000000..1390bfc12686c
--- /dev/null
+++ b/tools/kapi/.gitignore
@@ -0,0 +1,4 @@
+# Rust build artifacts
+/target/
+**/*.rs.bk
+
diff --git a/tools/kapi/Cargo.toml b/tools/kapi/Cargo.toml
new file mode 100644
index 0000000000000..7df8a159689f4
--- /dev/null
+++ b/tools/kapi/Cargo.toml
@@ -0,0 +1,19 @@
+[package]
+name = "kapi"
+version = "0.1.0"
+edition = "2021"
+authors = ["Sasha Levin <sashal@kernel.org>"]
+description = "Tool for extracting and displaying kernel API specifications"
+license = "GPL-2.0"
+
+[dependencies]
+goblin = "0.10"
+clap = { version = "4.4", features = ["derive"] }
+anyhow = "1.0"
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+regex = "1.10"
+walkdir = "2.4"
+
+[dev-dependencies]
+tempfile = "3.8"
diff --git a/tools/kapi/src/extractor/debugfs.rs b/tools/kapi/src/extractor/debugfs.rs
new file mode 100644
index 0000000000000..397363c4a0741
--- /dev/null
+++ b/tools/kapi/src/extractor/debugfs.rs
@@ -0,0 +1,578 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2026 Sasha Levin <sashal@kernel.org>
+
+use crate::formatter::OutputFormatter;
+use anyhow::{Context, Result, bail};
+use serde::Deserialize;
+use std::fs;
+use std::io::Write;
+use std::path::PathBuf;
+
+use super::{ApiExtractor, ApiSpec, CapabilitySpec, ErrorSpec, LockSpec, ParamSpec, ReturnSpec, display_api_spec};
+
+#[derive(Deserialize)]
+struct KernelApiJson {
+ name: String,
+ api_type: Option<String>,
+ version: Option<u32>,
+ description: Option<String>,
+ long_description: Option<String>,
+ context_flags: Option<u32>,
+ examples: Option<String>,
+ notes: Option<String>,
+ capabilities: Option<Vec<KernelCapabilityJson>>,
+ #[serde(default)]
+ parameters: Option<Vec<KernelParamJson>>,
+ #[serde(default)]
+ errors: Option<Vec<KernelErrorJson>>,
+ #[serde(default)]
+ return_spec: Option<KernelReturnJson>,
+ #[serde(default)]
+ locks: Option<Vec<KernelLockJson>>,
+}
+
+#[derive(Deserialize)]
+struct KernelParamJson {
+ name: String,
+ #[serde(rename = "type")]
+ type_name: Option<String>,
+ description: Option<String>,
+ #[serde(default)]
+ flags: u32,
+ #[serde(default)]
+ param_type: u32,
+}
+
+#[derive(Deserialize)]
+struct KernelErrorJson {
+ error_code: i32,
+ name: Option<String>,
+ condition: Option<String>,
+ description: Option<String>,
+}
+
+#[derive(Deserialize)]
+struct KernelReturnJson {
+ #[serde(rename = "type")]
+ type_name: Option<String>,
+ description: Option<String>,
+ #[serde(default)]
+ return_type: u32,
+ #[serde(default)]
+ check_type: u32,
+ success_value: Option<i64>,
+}
+
+#[derive(Deserialize)]
+struct KernelLockJson {
+ name: String,
+ #[serde(default)]
+ lock_type: u32,
+ #[serde(default)]
+ scope: u32,
+ description: Option<String>,
+}
+
+#[derive(Deserialize)]
+struct KernelCapabilityJson {
+ capability: i32,
+ name: String,
+ action: String,
+ allows: String,
+ without_cap: String,
+ check_condition: Option<String>,
+ priority: Option<u8>,
+ alternatives: Option<Vec<i32>>,
+}
+
+/// Extractor for kernel API specifications from debugfs
+pub struct DebugfsExtractor {
+ debugfs_path: PathBuf,
+}
+
+impl DebugfsExtractor {
+ /// Create a new debugfs extractor with the specified debugfs path
+ pub fn new(debugfs_path: Option<String>) -> Result<Self> {
+ let path = match debugfs_path {
+ Some(p) => PathBuf::from(p),
+ None => PathBuf::from("/sys/kernel/debug"),
+ };
+
+ // Check if the debugfs path exists
+ if !path.exists() {
+ bail!("Debugfs path does not exist: {}", path.display());
+ }
+
+ // Check if kapi directory exists
+ let kapi_path = path.join("kapi");
+ if !kapi_path.exists() {
+ bail!(
+ "Kernel API debugfs interface not found at: {}",
+ kapi_path.display()
+ );
+ }
+
+ Ok(Self { debugfs_path: path })
+ }
+
+ /// Parse the list file to get all available API names
+ fn parse_list_file(&self) -> Result<Vec<String>> {
+ let list_path = self.debugfs_path.join("kapi/list");
+ let content = fs::read_to_string(&list_path)
+ .with_context(|| format!("Failed to read {}", list_path.display()))?;
+
+ let mut apis = Vec::new();
+ let mut in_list = false;
+
+ for line in content.lines() {
+ if line.contains("===") {
+ in_list = true;
+ continue;
+ }
+
+ if in_list && line.starts_with("Total:") {
+ break;
+ }
+
+ if in_list && !line.trim().is_empty() {
+ // Extract API name from lines like "sys_read - Read from a file descriptor"
+ if let Some(name) = line.split(" - ").next() {
+ apis.push(name.trim().to_string());
+ }
+ }
+ }
+
+ Ok(apis)
+ }
+
+ /// Try to parse JSON content, convert context flags from u32 to string representations
+ fn parse_context_flags(flags: u32) -> Vec<String> {
+ let mut result = Vec::new();
+
+ // These values should match KAPI_CTX_* flags from kernel
+ if flags & (1 << 0) != 0 {
+ result.push("PROCESS".to_string());
+ }
+ if flags & (1 << 1) != 0 {
+ result.push("SOFTIRQ".to_string());
+ }
+ if flags & (1 << 2) != 0 {
+ result.push("HARDIRQ".to_string());
+ }
+ if flags & (1 << 3) != 0 {
+ result.push("NMI".to_string());
+ }
+ if flags & (1 << 4) != 0 {
+ result.push("ATOMIC".to_string());
+ }
+ if flags & (1 << 5) != 0 {
+ result.push("SLEEPABLE".to_string());
+ }
+ if flags & (1 << 6) != 0 {
+ result.push("PREEMPT_DISABLED".to_string());
+ }
+ if flags & (1 << 7) != 0 {
+ result.push("IRQ_DISABLED".to_string());
+ }
+
+ result
+ }
+
+ /// Convert capability action from kernel representation
+ fn parse_capability_action(action: &str) -> String {
+ match action {
+ "bypass_check" => "Bypasses check".to_string(),
+ "increase_limit" => "Increases limit".to_string(),
+ "override_restriction" => "Overrides restriction".to_string(),
+ "grant_permission" => "Grants permission".to_string(),
+ "modify_behavior" => "Modifies behavior".to_string(),
+ "access_resource" => "Allows resource access".to_string(),
+ "perform_operation" => "Allows operation".to_string(),
+ _ => action.to_string(),
+ }
+ }
+
+ /// Try to parse as JSON first
+ fn try_parse_json(&self, content: &str) -> Option<ApiSpec> {
+ let json_data: KernelApiJson = serde_json::from_str(content).ok()?;
+
+ let mut spec = ApiSpec {
+ name: json_data.name,
+ api_type: json_data.api_type.unwrap_or_else(|| "unknown".to_string()),
+ description: json_data.description,
+ long_description: json_data.long_description,
+ version: json_data.version.map(|v| v.to_string()),
+ context_flags: json_data
+ .context_flags
+ .map_or_else(Vec::new, Self::parse_context_flags),
+ param_count: None,
+ error_count: None,
+ examples: json_data.examples,
+ notes: json_data.notes,
+ subsystem: None, // Not in current JSON format
+ sysfs_path: None, // Not in current JSON format
+ permissions: None, // Not in current JSON format
+ socket_state: None,
+ protocol_behaviors: vec![],
+ addr_families: vec![],
+ buffer_spec: None,
+ async_spec: None,
+ net_data_transfer: None,
+ capabilities: vec![],
+ parameters: vec![],
+ return_spec: None,
+ errors: vec![],
+ signals: vec![],
+ signal_masks: vec![],
+ side_effects: vec![],
+ state_transitions: vec![],
+ constraints: vec![],
+ locks: vec![],
+ struct_specs: vec![],
+ };
+
+ // Convert capabilities
+ if let Some(caps) = json_data.capabilities {
+ for cap in caps {
+ spec.capabilities.push(CapabilitySpec {
+ capability: cap.capability,
+ name: cap.name,
+ action: Self::parse_capability_action(&cap.action),
+ allows: cap.allows,
+ without_cap: cap.without_cap,
+ check_condition: cap.check_condition,
+ priority: cap.priority,
+ alternatives: cap.alternatives.unwrap_or_default(),
+ });
+ }
+ }
+
+ // Convert parameters
+ if let Some(params) = json_data.parameters {
+ for (i, p) in params.into_iter().enumerate() {
+ spec.parameters.push(ParamSpec {
+ index: i as u32,
+ name: p.name,
+ type_name: p.type_name.unwrap_or_default(),
+ description: p.description.unwrap_or_default(),
+ flags: p.flags,
+ param_type: p.param_type,
+ constraint_type: 0,
+ constraint: None,
+ min_value: None,
+ max_value: None,
+ valid_mask: None,
+ enum_values: vec![],
+ size: None,
+ alignment: None,
+ });
+ }
+ spec.param_count = Some(spec.parameters.len() as u32);
+ }
+
+ // Convert errors
+ if let Some(errors) = json_data.errors {
+ for e in errors {
+ spec.errors.push(ErrorSpec {
+ error_code: e.error_code,
+ name: e.name.unwrap_or_default(),
+ condition: e.condition.unwrap_or_default(),
+ description: e.description.unwrap_or_default(),
+ });
+ }
+ spec.error_count = Some(spec.errors.len() as u32);
+ }
+
+ // Convert return spec
+ if let Some(ret) = json_data.return_spec {
+ spec.return_spec = Some(ReturnSpec {
+ type_name: ret.type_name.unwrap_or_default(),
+ description: ret.description.unwrap_or_default(),
+ return_type: ret.return_type,
+ check_type: ret.check_type,
+ success_value: ret.success_value,
+ success_min: None,
+ success_max: None,
+ error_values: vec![],
+ });
+ }
+
+ // Convert locks
+ if let Some(locks) = json_data.locks {
+ for l in locks {
+ spec.locks.push(LockSpec {
+ lock_name: l.name,
+ lock_type: l.lock_type,
+ scope: l.scope,
+ description: l.description.unwrap_or_default(),
+ });
+ }
+ }
+
+ Some(spec)
+ }
+
+ /// Parse a single API specification file
+ fn parse_spec_file(&self, api_name: &str) -> Result<ApiSpec> {
+ let spec_path = self.debugfs_path.join(format!("kapi/specs/{}", api_name));
+ let content = fs::read_to_string(&spec_path)
+ .with_context(|| format!("Failed to read {}", spec_path.display()))?;
+
+ // Try JSON parsing first
+ if let Some(spec) = self.try_parse_json(&content) {
+ return Ok(spec);
+ }
+
+ // Fall back to plain text parsing
+ let mut spec = ApiSpec {
+ name: api_name.to_string(),
+ api_type: "unknown".to_string(),
+ description: None,
+ long_description: None,
+ version: None,
+ context_flags: Vec::new(),
+ param_count: None,
+ error_count: None,
+ examples: None,
+ notes: None,
+ subsystem: None,
+ sysfs_path: None,
+ permissions: None,
+ socket_state: None,
+ protocol_behaviors: vec![],
+ addr_families: vec![],
+ buffer_spec: None,
+ async_spec: None,
+ net_data_transfer: None,
+ capabilities: vec![],
+ parameters: vec![],
+ return_spec: None,
+ errors: vec![],
+ signals: vec![],
+ signal_masks: vec![],
+ side_effects: vec![],
+ state_transitions: vec![],
+ constraints: vec![],
+ locks: vec![],
+ struct_specs: vec![],
+ };
+
+ // Parse the content
+ let mut collecting_multiline = false;
+ let mut multiline_buffer = String::new();
+ let mut multiline_field = "";
+ let mut parsing_capability = false;
+ let mut current_capability: Option<CapabilitySpec> = None;
+
+ for line in content.lines() {
+ // Handle capability sections
+ if line.starts_with("Capabilities (") {
+ continue; // Skip the header
+ }
+ if line.starts_with(" ") && line.contains(" (") && line.ends_with("):") {
+ // Start of a capability entry like " CAP_IPC_LOCK (14):"
+ if let Some(cap) = current_capability.take() {
+ spec.capabilities.push(cap);
+ }
+
+ let parts: Vec<&str> = line.trim().split(" (").collect();
+ if parts.len() == 2 {
+ let cap_name = parts[0].to_string();
+ let cap_id = parts[1].trim_end_matches("):").parse().unwrap_or(0);
+ current_capability = Some(CapabilitySpec {
+ capability: cap_id,
+ name: cap_name,
+ action: String::new(),
+ allows: String::new(),
+ without_cap: String::new(),
+ check_condition: None,
+ priority: None,
+ alternatives: Vec::new(),
+ });
+ parsing_capability = true;
+ }
+ continue;
+ }
+ if parsing_capability && line.starts_with(" ") {
+ // Parse capability fields
+ if let Some(ref mut cap) = current_capability {
+ if let Some(action) = line.strip_prefix(" Action: ") {
+ cap.action = action.to_string();
+ } else if let Some(allows) = line.strip_prefix(" Allows: ") {
+ cap.allows = allows.to_string();
+ } else if let Some(without) = line.strip_prefix(" Without: ") {
+ cap.without_cap = without.to_string();
+ } else if let Some(cond) = line.strip_prefix(" Condition: ") {
+ cap.check_condition = Some(cond.to_string());
+ } else if let Some(prio) = line.strip_prefix(" Priority: ") {
+ cap.priority = prio.parse().ok();
+ } else if let Some(alts) = line.strip_prefix(" Alternatives: ") {
+ cap.alternatives =
+ alts.split(", ").filter_map(|s| s.parse().ok()).collect();
+ }
+ }
+ continue;
+ }
+ if parsing_capability && !line.starts_with(" ") {
+ // End of capabilities section
+ if let Some(cap) = current_capability.take() {
+ spec.capabilities.push(cap);
+ }
+ parsing_capability = false;
+ }
+
+ // Handle section headers
+ if line.starts_with("Parameters (") {
+ if let Some(count_str) = line
+ .strip_prefix("Parameters (")
+ .and_then(|s| s.strip_suffix("):"))
+ {
+ spec.param_count = count_str.parse().ok();
+ }
+ continue;
+ } else if line.starts_with("Errors (") {
+ if let Some(count_str) = line
+ .strip_prefix("Errors (")
+ .and_then(|s| s.strip_suffix("):"))
+ {
+ spec.error_count = count_str.parse().ok();
+ }
+ continue;
+ } else if line.starts_with("Examples:") {
+ collecting_multiline = true;
+ multiline_field = "examples";
+ multiline_buffer.clear();
+ continue;
+ } else if line.starts_with("Notes:") {
+ collecting_multiline = true;
+ multiline_field = "notes";
+ multiline_buffer.clear();
+ continue;
+ }
+
+ // Handle multiline sections
+ if collecting_multiline {
+ // Terminate multiline on known field patterns or double blank line
+ let is_field = line.starts_with("Description: ")
+ || line.starts_with("Long description: ")
+ || line.starts_with("Version: ")
+ || line.starts_with("Context flags: ")
+ || line.starts_with("Subsystem: ")
+ || line.starts_with("Sysfs Path: ")
+ || line.starts_with("Permissions: ")
+ || line.starts_with("Parameters (")
+ || line.starts_with("Errors (")
+ || line.starts_with("Capabilities (");
+ if is_field || (line.trim().is_empty() && multiline_buffer.ends_with("\n\n")) {
+ collecting_multiline = false;
+ match multiline_field {
+ "examples" => spec.examples = Some(multiline_buffer.trim().to_string()),
+ "notes" => spec.notes = Some(multiline_buffer.trim().to_string()),
+ _ => {}
+ }
+ multiline_buffer.clear();
+ if !is_field {
+ continue;
+ }
+ // Fall through to parse this line as a field
+ } else {
+ if !multiline_buffer.is_empty() {
+ multiline_buffer.push('\n');
+ }
+ multiline_buffer.push_str(line);
+ continue;
+ }
+ }
+
+ // Parse regular fields
+ if let Some(desc) = line.strip_prefix("Description: ") {
+ spec.description = Some(desc.to_string());
+ } else if let Some(long_desc) = line.strip_prefix("Long description: ") {
+ spec.long_description = Some(long_desc.to_string());
+ } else if let Some(version) = line.strip_prefix("Version: ") {
+ spec.version = Some(version.to_string());
+ } else if let Some(flags) = line.strip_prefix("Context flags: ") {
+ spec.context_flags = flags.split_whitespace().map(str::to_string).collect();
+ } else if let Some(subsys) = line.strip_prefix("Subsystem: ") {
+ spec.subsystem = Some(subsys.to_string());
+ } else if let Some(path) = line.strip_prefix("Sysfs Path: ") {
+ spec.sysfs_path = Some(path.to_string());
+ } else if let Some(perms) = line.strip_prefix("Permissions: ") {
+ spec.permissions = Some(perms.to_string());
+ }
+ }
+
+ // Flush any remaining multiline buffer
+ if collecting_multiline {
+ match multiline_field {
+ "examples" => spec.examples = Some(multiline_buffer.trim().to_string()),
+ "notes" => spec.notes = Some(multiline_buffer.trim().to_string()),
+ _ => {}
+ }
+ }
+
+ // Handle any remaining capability
+ if let Some(cap) = current_capability.take() {
+ spec.capabilities.push(cap);
+ }
+
+ // Determine API type based on name
+ if api_name.starts_with("sys_") {
+ spec.api_type = "syscall".to_string();
+ } else if api_name.contains("_ioctl") || api_name.starts_with("ioctl_") {
+ spec.api_type = "ioctl".to_string();
+ } else if api_name.contains("sysfs")
+ || api_name.ends_with("_show")
+ || api_name.ends_with("_store")
+ {
+ spec.api_type = "sysfs".to_string();
+ } else {
+ spec.api_type = "function".to_string();
+ }
+
+ Ok(spec)
+ }
+}
+
+impl ApiExtractor for DebugfsExtractor {
+ fn extract_all(&self) -> Result<Vec<ApiSpec>> {
+ let api_names = self.parse_list_file()?;
+ let mut specs = Vec::new();
+
+ for name in api_names {
+ match self.parse_spec_file(&name) {
+ Ok(spec) => specs.push(spec),
+ Err(e) => {
+ eprintln!("Warning: failed to parse API spec '{}': {}", name, e);
+ }
+ }
+ }
+
+ Ok(specs)
+ }
+
+ fn extract_by_name(&self, name: &str) -> Result<Option<ApiSpec>> {
+ let api_names = self.parse_list_file()?;
+
+ if api_names.contains(&name.to_string()) {
+ Ok(Some(self.parse_spec_file(name)?))
+ } else {
+ Ok(None)
+ }
+ }
+
+ fn display_api_details(
+ &self,
+ api_name: &str,
+ formatter: &mut dyn OutputFormatter,
+ writer: &mut dyn Write,
+ ) -> Result<()> {
+ if let Some(spec) = self.extract_by_name(api_name)? {
+ display_api_spec(&spec, formatter, writer)?;
+ } else {
+ writeln!(writer, "API '{api_name}' not found in debugfs")?;
+ }
+
+ Ok(())
+ }
+}
diff --git a/tools/kapi/src/extractor/kerneldoc_parser.rs b/tools/kapi/src/extractor/kerneldoc_parser.rs
new file mode 100644
index 0000000000000..f3183e71a4402
--- /dev/null
+++ b/tools/kapi/src/extractor/kerneldoc_parser.rs
@@ -0,0 +1,1555 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2026 Sasha Levin <sashal@kernel.org>
+
+use super::{
+ ApiSpec, CapabilitySpec, ConstraintSpec, ErrorSpec, LockSpec, ParamSpec,
+ ReturnSpec, SideEffectSpec, SignalSpec, StateTransitionSpec, StructSpec,
+ StructFieldSpec,
+};
+use anyhow::Result;
+use std::collections::HashMap;
+
+/// Real kerneldoc parser that extracts KAPI annotations
+pub struct KerneldocParserImpl;
+
+/// What block are we currently inside?
+#[derive(Debug, Clone, PartialEq)]
+enum BlockContext {
+ None,
+ Param(String), // param: <name>
+ Error(String), // error: <name>
+ Signal, // signal: <name>
+ Capability, // capability: <name>
+ SideEffect, // side-effect: <type>
+ StateTransition, // state-trans: ...
+ Constraint, // constraint: <name>
+ Lock, // lock: <name>
+ Return, // return:
+}
+
+impl KerneldocParserImpl {
+ pub fn new() -> Self {
+ KerneldocParserImpl
+ }
+
+ pub fn parse_kerneldoc(
+ &self,
+ doc: &str,
+ name: &str,
+ api_type: &str,
+ signature: Option<&str>,
+ ) -> Result<ApiSpec> {
+ let mut spec = ApiSpec {
+ name: name.to_string(),
+ api_type: api_type.to_string(),
+ ..Default::default()
+ };
+
+ let lines: Vec<&str> = doc.lines().collect();
+
+ // Extract main description from function name line
+ if let Some(first_line) = lines.first() {
+ if let Some((_, desc)) = first_line.split_once(" - ") {
+ spec.description = Some(desc.trim().to_string());
+ }
+ }
+
+ // Extract type names from SYSCALL_DEFINE signature
+ let type_map = if let Some(sig) = signature {
+ self.extract_types_from_signature(sig)
+ } else {
+ HashMap::new()
+ };
+
+ // Keep track of parameters we've seen (from @param lines)
+ let mut param_map: HashMap<String, ParamSpec> = HashMap::new();
+ let mut struct_fields: Vec<StructFieldSpec> = Vec::new();
+
+ // Current block being parsed
+ let mut block = BlockContext::None;
+
+ // Temporary storage for current block items
+ let mut current_lock: Option<LockSpec> = None;
+ let mut current_signal: Option<SignalSpec> = None;
+ let mut current_capability: Option<CapabilitySpec> = None;
+ let mut current_side_effect: Option<SideEffectSpec> = None;
+ let mut current_constraint: Option<ConstraintSpec> = None;
+ let mut current_error: Option<ErrorSpec> = None;
+ let mut current_return: Option<ReturnSpec> = None;
+
+ let mut i = 0;
+
+ while i < lines.len() {
+ let line = lines[i];
+ let trimmed = line.trim();
+
+ // Skip empty lines
+ if trimmed.is_empty() {
+ i += 1;
+ continue;
+ }
+
+ // Check if this is an indented continuation line (part of current block)
+ let is_indented = line.starts_with(" ") || line.starts_with('\t');
+
+ // If indented and we're in a block, parse as block attribute
+ if is_indented && block != BlockContext::None {
+ self.parse_block_attribute(trimmed, &block, &mut param_map,
+ &mut current_error, &mut current_signal,
+ &mut current_capability, &mut current_side_effect,
+ &mut current_constraint, &mut current_lock,
+ &mut current_return);
+ i += 1;
+ continue;
+ }
+
+ // Not indented or not in block — flush current block if any
+ self.flush_block(&mut block, &mut spec, &mut current_error,
+ &mut current_signal, &mut current_capability,
+ &mut current_side_effect, &mut current_constraint,
+ &mut current_lock, &mut current_return);
+
+ // Parse top-level annotations
+ if let Some(rest) = trimmed.strip_prefix("@") {
+ // @param: description — standard kerneldoc parameter
+ if let Some((param_name, desc)) = rest.split_once(':') {
+ let param_name = param_name.trim();
+ let desc = desc.trim();
+ if !param_name.contains('-') {
+ let idx = param_map.len() as u32;
+ let type_name = type_map.get(param_name)
+ .cloned()
+ .unwrap_or_default();
+ param_map.insert(param_name.to_string(), ParamSpec {
+ index: idx,
+ name: param_name.to_string(),
+ type_name,
+ description: desc.to_string(),
+ flags: 0,
+ param_type: 0,
+ constraint_type: 0,
+ constraint: None,
+ min_value: None,
+ max_value: None,
+ valid_mask: None,
+ enum_values: vec![],
+ size: None,
+ alignment: None,
+ });
+ }
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("long-desc:") {
+ let (val, next_i) = self.collect_multiline_value(&lines, i, rest);
+ spec.long_description = Some(val);
+ i = next_i;
+ continue;
+ } else if let Some(rest) = trimmed.strip_prefix("context-flags:") {
+ spec.context_flags = self.parse_context_flags(rest.trim());
+ } else if let Some(rest) = trimmed.strip_prefix("param-count:") {
+ spec.param_count = rest.trim().parse().ok();
+ }
+ // Flat param-* annotations (alternative format)
+ else if let Some(rest) = trimmed.strip_prefix("param-type:") {
+ let parts: Vec<&str> = rest.split(',').map(|s| s.trim()).collect();
+ if parts.len() >= 2 {
+ if let Some(param) = param_map.get_mut(parts[0]) {
+ param.param_type = self.parse_param_type(parts[1]);
+ }
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("param-flags:") {
+ let parts: Vec<&str> = rest.split(',').map(|s| s.trim()).collect();
+ if parts.len() >= 2 {
+ if let Some(param) = param_map.get_mut(parts[0]) {
+ param.flags = self.parse_param_flags(parts[1]);
+ }
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("param-range:") {
+ let parts: Vec<&str> = rest.split(',').map(|s| s.trim()).collect();
+ if parts.len() >= 3 {
+ if let Some(param) = param_map.get_mut(parts[0]) {
+ param.min_value = parts[1].parse().ok();
+ param.max_value = parts[2].parse().ok();
+ param.constraint_type = 1; // KAPI_CONSTRAINT_RANGE
+ }
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("param-constraint:") {
+ let parts: Vec<&str> = rest.splitn(2, ',').map(|s| s.trim()).collect();
+ if parts.len() >= 2 {
+ if let Some(param) = param_map.get_mut(parts[0]) {
+ param.constraint = Some(parts[1].to_string());
+ }
+ }
+ }
+ // Block-start annotations
+ else if let Some(rest) = trimmed.strip_prefix("param:") {
+ let param_name = rest.trim().to_string();
+ block = BlockContext::Param(param_name.clone());
+ // Ensure param exists in map
+ if !param_map.contains_key(&param_name) {
+ let idx = param_map.len() as u32;
+ let type_name = type_map.get(param_name.as_str())
+ .cloned()
+ .unwrap_or_default();
+ param_map.insert(param_name.clone(), ParamSpec {
+ index: idx,
+ name: param_name,
+ type_name,
+ description: String::new(),
+ flags: 0,
+ param_type: 0,
+ constraint_type: 0,
+ constraint: None,
+ min_value: None,
+ max_value: None,
+ valid_mask: None,
+ enum_values: vec![],
+ size: None,
+ alignment: None,
+ });
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("error:") {
+ // error: NAME, condition
+ let parts: Vec<&str> = rest.splitn(2, ',').map(|s| s.trim()).collect();
+ if !parts.is_empty() {
+ let error_name = parts[0].to_string();
+ let condition = if parts.len() >= 2 {
+ parts[1].to_string()
+ } else {
+ String::new()
+ };
+ let error_code = self.error_name_to_code(&error_name);
+ current_error = Some(ErrorSpec {
+ error_code,
+ name: error_name.clone(),
+ condition,
+ description: String::new(),
+ });
+ block = BlockContext::Error(error_name);
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("signal:") {
+ let signal_name = rest.trim().to_string();
+ current_signal = Some(SignalSpec {
+ signal_num: 0,
+ signal_name,
+ direction: 1,
+ action: 0,
+ target: None,
+ condition: None,
+ description: None,
+ restartable: false,
+ timing: 0,
+ priority: 0,
+ interruptible: false,
+ queue: None,
+ sa_flags: 0,
+ sa_flags_required: 0,
+ sa_flags_forbidden: 0,
+ state_required: 0,
+ state_forbidden: 0,
+ error_on_signal: None,
+ });
+ block = BlockContext::Signal;
+ } else if let Some(rest) = trimmed.strip_prefix("capability:") {
+ let parts: Vec<&str> = rest.split(',').map(|s| s.trim()).collect();
+ if !parts.is_empty() {
+ let cap_name = parts[0].to_string();
+ let cap_value = self.parse_capability_value(&cap_name);
+ // If we have 3 parts, it's flat format: capability: CAP, action, name
+ let (action, name) = if parts.len() >= 3 {
+ (parts[1].to_string(), parts[2].to_string())
+ } else {
+ (String::new(), cap_name.clone())
+ };
+ current_capability = Some(CapabilitySpec {
+ capability: cap_value,
+ name,
+ action,
+ allows: String::new(),
+ without_cap: String::new(),
+ check_condition: None,
+ priority: Some(0),
+ alternatives: vec![],
+ });
+ block = BlockContext::Capability;
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("side-effect:") {
+ // Could be flat format (comma-separated) or block start
+ let rest = rest.trim();
+ // Check if it's the flat format with commas
+ let comma_parts: Vec<&str> = rest.splitn(3, ',').map(|s| s.trim()).collect();
+ if comma_parts.len() >= 3 {
+ // Flat format: side-effect: TYPE, target, desc
+ let mut effect = SideEffectSpec {
+ effect_type: self.parse_effect_type(comma_parts[0]),
+ target: comma_parts[1].to_string(),
+ condition: None,
+ description: comma_parts[2].to_string(),
+ reversible: false,
+ };
+ if comma_parts[2].contains("reversible=yes") {
+ effect.reversible = true;
+ }
+ spec.side_effects.push(effect);
+ } else {
+ // Block format: side-effect: TYPE
+ current_side_effect = Some(SideEffectSpec {
+ effect_type: self.parse_effect_type(rest),
+ target: String::new(),
+ condition: None,
+ description: String::new(),
+ reversible: false,
+ });
+ block = BlockContext::SideEffect;
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("state-trans:") {
+ let parts: Vec<&str> = rest.split(',').map(|s| s.trim()).collect();
+ if parts.len() >= 4 {
+ spec.state_transitions.push(StateTransitionSpec {
+ object: parts[0].to_string(),
+ from_state: parts[1].to_string(),
+ to_state: parts[2].to_string(),
+ condition: None,
+ description: parts[3].to_string(),
+ });
+ }
+ block = BlockContext::StateTransition;
+ } else if let Some(rest) = trimmed.strip_prefix("constraint:") {
+ let rest = rest.trim();
+ // Could be flat format: constraint: name, desc
+ // Or block format: constraint: name
+ let parts: Vec<&str> = rest.splitn(2, ',').map(|s| s.trim()).collect();
+ if parts.len() >= 2 {
+ // Flat format
+ current_constraint = Some(ConstraintSpec {
+ name: parts[0].to_string(),
+ description: parts[1].to_string(),
+ expression: None,
+ });
+ } else {
+ // Block format
+ current_constraint = Some(ConstraintSpec {
+ name: rest.to_string(),
+ description: String::new(),
+ expression: None,
+ });
+ }
+ block = BlockContext::Constraint;
+ } else if let Some(rest) = trimmed.strip_prefix("constraint-expr:") {
+ // Flat format: constraint-expr: name, expr
+ let parts: Vec<&str> = rest.splitn(2, ',').map(|s| s.trim()).collect();
+ if parts.len() >= 2 {
+ if let Some(constraint) = spec.constraints.iter_mut().find(|c| c.name == parts[0]) {
+ constraint.expression = Some(parts[1].to_string());
+ }
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("lock:") {
+ let rest = rest.trim();
+ // Could be flat: lock: name, type
+ // Or block: lock: name
+ let parts: Vec<&str> = rest.split(',').map(|s| s.trim()).collect();
+ if parts.len() >= 2 {
+ current_lock = Some(LockSpec {
+ lock_name: parts[0].to_string(),
+ lock_type: self.parse_lock_type(parts[1]),
+ scope: super::KAPI_LOCK_INTERNAL,
+ description: String::new(),
+ });
+ } else {
+ current_lock = Some(LockSpec {
+ lock_name: rest.to_string(),
+ lock_type: 0,
+ scope: super::KAPI_LOCK_INTERNAL,
+ description: String::new(),
+ });
+ }
+ block = BlockContext::Lock;
+ }
+ // Flat signal-* attributes (alternative format)
+ else if let Some(rest) = trimmed.strip_prefix("signal-direction:") {
+ if let Some(signal) = current_signal.as_mut() {
+ signal.direction = self.parse_signal_direction(rest.trim());
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("signal-action:") {
+ if let Some(signal) = current_signal.as_mut() {
+ signal.action = self.parse_signal_action(rest.trim());
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("signal-condition:") {
+ if let Some(signal) = current_signal.as_mut() {
+ let (val, next_i) = self.collect_multiline_value(&lines, i, rest);
+ signal.condition = Some(val);
+ i = next_i;
+ continue;
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("signal-desc:") {
+ if let Some(signal) = current_signal.as_mut() {
+ let (val, next_i) = self.collect_multiline_value(&lines, i, rest);
+ signal.description = Some(val);
+ i = next_i;
+ continue;
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("signal-timing:") {
+ if let Some(signal) = current_signal.as_mut() {
+ signal.timing = self.parse_signal_timing(rest.trim());
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("signal-priority:") {
+ if let Some(signal) = current_signal.as_mut() {
+ signal.priority = rest.trim().parse().unwrap_or(0);
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("signal-interruptible:") {
+ if let Some(signal) = current_signal.as_mut() {
+ let val = rest.trim().to_lowercase();
+ signal.interruptible = !matches!(val.as_str(), "no" | "false" | "0");
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("signal-state-req:") {
+ if let Some(signal) = current_signal.as_mut() {
+ signal.state_required = self.parse_signal_state(rest.trim());
+ }
+ }
+ // Flat capability-* attributes
+ else if let Some(rest) = trimmed.strip_prefix("capability-allows:") {
+ if let Some(cap) = current_capability.as_mut() {
+ let (val, next_i) = self.collect_multiline_value(&lines, i, rest);
+ cap.allows = val;
+ i = next_i;
+ continue;
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("capability-without:") {
+ if let Some(cap) = current_capability.as_mut() {
+ let (val, next_i) = self.collect_multiline_value(&lines, i, rest);
+ cap.without_cap = val;
+ i = next_i;
+ continue;
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("capability-condition:") {
+ if let Some(cap) = current_capability.as_mut() {
+ let (val, next_i) = self.collect_multiline_value(&lines, i, rest);
+ cap.check_condition = Some(val);
+ i = next_i;
+ continue;
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("capability-priority:") {
+ if let Some(cap) = current_capability.as_mut() {
+ cap.priority = rest.trim().parse().ok();
+ }
+ }
+ // Lock flat attributes
+ else if let Some(rest) = trimmed.strip_prefix("lock-scope:") {
+ if let Some(lock) = current_lock.as_mut() {
+ lock.scope = match rest.trim() {
+ "internal" => super::KAPI_LOCK_INTERNAL,
+ "acquires" => super::KAPI_LOCK_ACQUIRES,
+ "releases" => super::KAPI_LOCK_RELEASES,
+ "caller_held" => super::KAPI_LOCK_CALLER_HELD,
+ _ => super::KAPI_LOCK_INTERNAL,
+ };
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("lock-desc:") {
+ if let Some(lock) = current_lock.as_mut() {
+ let (val, next_i) = self.collect_multiline_value(&lines, i, rest);
+ lock.description = val;
+ i = next_i;
+ continue;
+ }
+ }
+ // Struct field annotations
+ else if let Some(rest) = trimmed.strip_prefix("struct-field:") {
+ let parts: Vec<&str> = rest.split(',').map(|s| s.trim()).collect();
+ if parts.len() >= 3 {
+ struct_fields.push(StructFieldSpec {
+ name: parts[0].to_string(),
+ field_type: self.parse_field_type(parts[1]),
+ type_name: parts[1].to_string(),
+ offset: 0,
+ size: 0,
+ flags: 0,
+ constraint_type: 0,
+ min_value: 0,
+ max_value: 0,
+ valid_mask: 0,
+ description: parts[2].to_string(),
+ });
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("struct-field-range:") {
+ let parts: Vec<&str> = rest.split(',').map(|s| s.trim()).collect();
+ if parts.len() >= 3 {
+ if let Some(field) = struct_fields.iter_mut().find(|f| f.name == parts[0]) {
+ field.min_value = parts[1].parse().unwrap_or(0);
+ field.max_value = parts[2].parse().unwrap_or(0);
+ field.constraint_type = 1;
+ }
+ }
+ }
+ // Other top-level annotations
+ else if let Some(rest) = trimmed.strip_prefix("return:") {
+ let rest = rest.trim();
+ if rest.is_empty() {
+ // Block format
+ current_return = Some(ReturnSpec {
+ type_name: String::new(),
+ description: String::new(),
+ return_type: 0,
+ check_type: 0,
+ success_value: None,
+ success_min: None,
+ success_max: None,
+ error_values: vec![],
+ });
+ block = BlockContext::Return;
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("return-type:") {
+ if spec.return_spec.is_none() {
+ spec.return_spec = Some(ReturnSpec {
+ type_name: rest.trim().to_string(),
+ description: String::new(),
+ return_type: self.parse_param_type(rest.trim()),
+ check_type: 0,
+ success_value: None,
+ success_min: None,
+ success_max: None,
+ error_values: vec![],
+ });
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("return-check-type:") {
+ if let Some(ret) = spec.return_spec.as_mut() {
+ ret.check_type = self.parse_return_check_type(rest.trim());
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("return-success:") {
+ if let Some(ret) = spec.return_spec.as_mut() {
+ ret.success_value = rest.trim().parse().ok();
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("examples:") {
+ let (val, next_i) = self.collect_multiline_value(&lines, i, rest);
+ spec.examples = Some(val);
+ i = next_i;
+ continue;
+ } else if let Some(rest) = trimmed.strip_prefix("notes:") {
+ let (val, next_i) = self.collect_multiline_value(&lines, i, rest);
+ spec.notes = Some(val);
+ i = next_i;
+ continue;
+ }
+
+ i += 1;
+ }
+
+ // Flush any remaining block
+ self.flush_block(&mut block, &mut spec, &mut current_error,
+ &mut current_signal, &mut current_capability,
+ &mut current_side_effect, &mut current_constraint,
+ &mut current_lock, &mut current_return);
+
+ // Convert param_map to vec preserving order
+ let mut params: Vec<ParamSpec> = param_map.into_values().collect();
+ params.sort_by_key(|p| p.index);
+ spec.parameters = params;
+
+ // Create struct spec if we have fields
+ if !struct_fields.is_empty() {
+ spec.struct_specs.push(StructSpec {
+ name: format!("struct {name}"),
+ size: 0,
+ alignment: 0,
+ field_count: struct_fields.len() as u32,
+ fields: struct_fields,
+ description: "Structure specification".to_string(),
+ });
+ }
+
+ Ok(spec)
+ }
+
+ /// Parse an indented attribute line within a block
+ fn parse_block_attribute(
+ &self,
+ trimmed: &str,
+ block: &BlockContext,
+ param_map: &mut HashMap<String, ParamSpec>,
+ current_error: &mut Option<ErrorSpec>,
+ current_signal: &mut Option<SignalSpec>,
+ current_capability: &mut Option<CapabilitySpec>,
+ current_side_effect: &mut Option<SideEffectSpec>,
+ current_constraint: &mut Option<ConstraintSpec>,
+ current_lock: &mut Option<LockSpec>,
+ current_return: &mut Option<ReturnSpec>,
+ ) {
+ match block {
+ BlockContext::Param(param_name) => {
+ if let Some(param) = param_map.get_mut(param_name) {
+ if let Some(rest) = trimmed.strip_prefix("type:") {
+ param.param_type = self.parse_param_type(rest.trim());
+ } else if let Some(rest) = trimmed.strip_prefix("flags:") {
+ param.flags = self.parse_param_flags(rest.trim());
+ } else if let Some(rest) = trimmed.strip_prefix("constraint-type:") {
+ param.constraint_type = self.parse_constraint_type(rest.trim());
+ } else if let Some(rest) = trimmed.strip_prefix("valid-mask:") {
+ // Don't try to parse symbolic mask values — leave for binary
+ let _ = rest; // valid-mask parsing needs constant resolution
+ } else if let Some(rest) = trimmed.strip_prefix("constraint:") {
+ // May be multiline — append
+ let text = rest.trim();
+ if param.constraint.is_none() {
+ param.constraint = Some(text.to_string());
+ } else if let Some(c) = param.constraint.as_mut() {
+ c.push(' ');
+ c.push_str(text);
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("range:") {
+ let parts: Vec<&str> = rest.split(',').map(|s| s.trim()).collect();
+ if parts.len() >= 2 {
+ param.min_value = parts[0].parse().ok();
+ param.max_value = parts[1].parse().ok();
+ param.constraint_type = 1; // KAPI_CONSTRAINT_RANGE
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("desc:") {
+ param.description = rest.trim().to_string();
+ } else if !trimmed.contains(':') || trimmed.starts_with(" ") {
+ // Continuation of previous attribute (e.g., multiline constraint)
+ if let Some(c) = param.constraint.as_mut() {
+ c.push(' ');
+ c.push_str(trimmed);
+ }
+ }
+ }
+ }
+ BlockContext::Error(_) => {
+ if let Some(error) = current_error.as_mut() {
+ if let Some(rest) = trimmed.strip_prefix("desc:") {
+ let text = rest.trim().to_string();
+ if error.description.is_empty() {
+ error.description = text;
+ } else {
+ error.description.push(' ');
+ error.description.push_str(&text);
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("condition:") {
+ error.condition = rest.trim().to_string();
+ } else {
+ // Continuation of description
+ if !error.description.is_empty() {
+ error.description.push(' ');
+ error.description.push_str(trimmed);
+ }
+ }
+ }
+ }
+ BlockContext::Signal => {
+ if let Some(signal) = current_signal.as_mut() {
+ if let Some(rest) = trimmed.strip_prefix("direction:") {
+ signal.direction = self.parse_signal_direction(rest.trim());
+ } else if let Some(rest) = trimmed.strip_prefix("action:") {
+ signal.action = self.parse_signal_action(rest.trim());
+ } else if let Some(rest) = trimmed.strip_prefix("condition:") {
+ signal.condition = Some(rest.trim().to_string());
+ } else if let Some(rest) = trimmed.strip_prefix("desc:") {
+ let text = rest.trim().to_string();
+ if signal.description.is_none() {
+ signal.description = Some(text);
+ } else if let Some(d) = signal.description.as_mut() {
+ d.push(' ');
+ d.push_str(&text);
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("error:") {
+ let code_str = rest.trim().trim_start_matches('-');
+ if let Ok(code) = code_str.parse::<i32>() {
+ signal.error_on_signal = Some(code);
+ } else {
+ signal.error_on_signal = Some(self.error_name_to_code(rest.trim().trim_start_matches('-')));
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("timing:") {
+ signal.timing = self.parse_signal_timing(rest.trim());
+ } else if let Some(rest) = trimmed.strip_prefix("restartable:") {
+ let val = rest.trim().to_lowercase();
+ signal.restartable = matches!(val.as_str(), "yes" | "true" | "1");
+ } else if let Some(rest) = trimmed.strip_prefix("interruptible:") {
+ let val = rest.trim().to_lowercase();
+ signal.interruptible = matches!(val.as_str(), "yes" | "true" | "1");
+ } else if let Some(rest) = trimmed.strip_prefix("priority:") {
+ signal.priority = rest.trim().parse().unwrap_or(0);
+ } else {
+ // Continuation of description
+ if let Some(d) = signal.description.as_mut() {
+ d.push(' ');
+ d.push_str(trimmed);
+ }
+ }
+ }
+ }
+ BlockContext::Capability => {
+ if let Some(cap) = current_capability.as_mut() {
+ if let Some(rest) = trimmed.strip_prefix("type:") {
+ cap.action = rest.trim().to_string();
+ } else if let Some(rest) = trimmed.strip_prefix("allows:") {
+ cap.allows = rest.trim().to_string();
+ } else if let Some(rest) = trimmed.strip_prefix("without:") {
+ cap.without_cap = rest.trim().to_string();
+ } else if let Some(rest) = trimmed.strip_prefix("condition:") {
+ cap.check_condition = Some(rest.trim().to_string());
+ } else if let Some(rest) = trimmed.strip_prefix("priority:") {
+ cap.priority = rest.trim().parse().ok();
+ }
+ }
+ }
+ BlockContext::SideEffect => {
+ if let Some(effect) = current_side_effect.as_mut() {
+ if let Some(rest) = trimmed.strip_prefix("target:") {
+ effect.target = rest.trim().to_string();
+ } else if let Some(rest) = trimmed.strip_prefix("condition:") {
+ effect.condition = Some(rest.trim().to_string());
+ } else if let Some(rest) = trimmed.strip_prefix("desc:") {
+ let text = rest.trim().to_string();
+ if effect.description.is_empty() {
+ effect.description = text;
+ } else {
+ effect.description.push(' ');
+ effect.description.push_str(&text);
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("reversible:") {
+ let val = rest.trim().to_lowercase();
+ effect.reversible = matches!(val.as_str(), "yes" | "true" | "1");
+ } else {
+ // Continuation of description
+ if !effect.description.is_empty() {
+ effect.description.push(' ');
+ effect.description.push_str(trimmed);
+ }
+ }
+ }
+ }
+ BlockContext::Constraint => {
+ if let Some(constraint) = current_constraint.as_mut() {
+ if let Some(rest) = trimmed.strip_prefix("desc:") {
+ let text = rest.trim().to_string();
+ if constraint.description.is_empty() {
+ constraint.description = text;
+ } else {
+ constraint.description.push(' ');
+ constraint.description.push_str(&text);
+ }
+ } else if let Some(rest) = trimmed.strip_prefix("expr:") {
+ constraint.expression = Some(rest.trim().to_string());
+ } else {
+ // Continuation of description
+ if !constraint.description.is_empty() {
+ constraint.description.push(' ');
+ constraint.description.push_str(trimmed);
+ }
+ }
+ }
+ }
+ BlockContext::Lock => {
+ if let Some(lock) = current_lock.as_mut() {
+ if let Some(rest) = trimmed.strip_prefix("type:") {
+ lock.lock_type = self.parse_lock_type(rest.trim());
+ } else if let Some(rest) = trimmed.strip_prefix("scope:") {
+ lock.scope = match rest.trim() {
+ "internal" => super::KAPI_LOCK_INTERNAL,
+ "acquires" => super::KAPI_LOCK_ACQUIRES,
+ "releases" => super::KAPI_LOCK_RELEASES,
+ "caller_held" => super::KAPI_LOCK_CALLER_HELD,
+ _ => super::KAPI_LOCK_INTERNAL,
+ };
+ } else if let Some(rest) = trimmed.strip_prefix("desc:") {
+ let text = rest.trim().to_string();
+ if lock.description.is_empty() {
+ lock.description = text;
+ } else {
+ lock.description.push(' ');
+ lock.description.push_str(&text);
+ }
+ } else if trimmed.starts_with("acquired:") || trimmed.starts_with("released:") {
+ // Ignored — handled via scope
+ } else {
+ // Continuation of description
+ if !lock.description.is_empty() {
+ lock.description.push(' ');
+ lock.description.push_str(trimmed);
+ }
+ }
+ }
+ }
+ BlockContext::Return => {
+ if let Some(ret) = current_return.as_mut() {
+ if let Some(rest) = trimmed.strip_prefix("type:") {
+ ret.type_name = rest.trim().to_string();
+ ret.return_type = self.parse_param_type(rest.trim());
+ } else if let Some(rest) = trimmed.strip_prefix("check-type:") {
+ ret.check_type = self.parse_return_check_type(rest.trim());
+ } else if let Some(rest) = trimmed.strip_prefix("success:") {
+ // Parse success value — could be "= 0", ">= 0", etc.
+ let val = rest.trim().trim_start_matches(|c: char| !c.is_ascii_digit() && c != '-');
+ ret.success_value = val.parse().ok();
+ } else if let Some(rest) = trimmed.strip_prefix("desc:") {
+ let text = rest.trim().to_string();
+ if ret.description.is_empty() {
+ ret.description = text;
+ } else {
+ ret.description.push(' ');
+ ret.description.push_str(&text);
+ }
+ } else {
+ // Continuation of description
+ if !ret.description.is_empty() {
+ ret.description.push(' ');
+ ret.description.push_str(trimmed);
+ }
+ }
+ }
+ }
+ BlockContext::StateTransition | BlockContext::None => {}
+ }
+ }
+
+ /// Flush the current block, pushing items into the spec
+ fn flush_block(
+ &self,
+ block: &mut BlockContext,
+ spec: &mut ApiSpec,
+ current_error: &mut Option<ErrorSpec>,
+ current_signal: &mut Option<SignalSpec>,
+ current_capability: &mut Option<CapabilitySpec>,
+ current_side_effect: &mut Option<SideEffectSpec>,
+ current_constraint: &mut Option<ConstraintSpec>,
+ current_lock: &mut Option<LockSpec>,
+ current_return: &mut Option<ReturnSpec>,
+ ) {
+ match block {
+ BlockContext::Error(_) => {
+ if let Some(error) = current_error.take() {
+ spec.errors.push(error);
+ }
+ }
+ BlockContext::Signal => {
+ if let Some(signal) = current_signal.take() {
+ spec.signals.push(signal);
+ }
+ }
+ BlockContext::Capability => {
+ if let Some(cap) = current_capability.take() {
+ spec.capabilities.push(cap);
+ }
+ }
+ BlockContext::SideEffect => {
+ if let Some(effect) = current_side_effect.take() {
+ spec.side_effects.push(effect);
+ }
+ }
+ BlockContext::Constraint => {
+ if let Some(constraint) = current_constraint.take() {
+ spec.constraints.push(constraint);
+ }
+ }
+ BlockContext::Lock => {
+ if let Some(lock) = current_lock.take() {
+ spec.locks.push(lock);
+ }
+ }
+ BlockContext::Return => {
+ if let Some(ret) = current_return.take() {
+ spec.return_spec = Some(ret);
+ }
+ }
+ _ => {}
+ }
+ *block = BlockContext::None;
+ }
+
+ /// Extract parameter type names from SYSCALL_DEFINE signature
+ fn extract_types_from_signature(&self, sig: &str) -> HashMap<String, String> {
+ let mut types = HashMap::new();
+
+ // Find content between outermost parens
+ let content = if let Some(start) = sig.find('(') {
+ let end = sig.rfind(')').unwrap_or(sig.len());
+ &sig[start + 1..end]
+ } else {
+ return types;
+ };
+
+ // Split by comma and process type/name pairs
+ // SYSCALL_DEFINE format: (syscall_name, type1, name1, type2, name2, ...)
+ let parts: Vec<&str> = content.split(',').map(|s| s.trim()).collect();
+
+ // Skip first part (syscall name), then process pairs
+ let mut i = 1;
+ while i + 1 < parts.len() {
+ let type_part = parts[i].trim();
+ let name_part = parts[i + 1].trim();
+
+ // Build the type_name string: "type name"
+ let type_name = format!("{} {}", type_part, name_part);
+ types.insert(name_part.to_string(), type_name);
+
+ i += 2;
+ }
+
+ types
+ }
+
+ fn collect_multiline_value(&self, lines: &[&str], start_idx: usize, first_part: &str) -> (String, usize) {
+ let mut result = String::from(first_part.trim());
+ let mut i = start_idx + 1;
+
+ while i < lines.len() {
+ let line = lines[i];
+
+ if self.is_annotation_line(line) {
+ break;
+ }
+
+ if !line.trim().is_empty() && line.starts_with(" ") {
+ if !result.is_empty() {
+ result.push(' ');
+ }
+ result.push_str(line.trim());
+ } else if line.trim().is_empty() {
+ i += 1;
+ continue;
+ } else {
+ break;
+ }
+
+ i += 1;
+ }
+
+ (result, i)
+ }
+
+ fn is_annotation_line(&self, line: &str) -> bool {
+ let trimmed = line.trim_start();
+ if !trimmed.contains(':') {
+ return false;
+ }
+ let annotations = [
+ "param:", "param-", "error:", "error-", "lock:", "lock-",
+ "signal:", "signal-", "side-effect:", "state-trans:",
+ "capability:", "capability-", "constraint:", "constraint-",
+ "struct-", "return:", "return-", "examples:", "notes:",
+ "since-", "context-", "long-desc:", "api-type:",
+ ];
+
+ for ann in &annotations {
+ if trimmed.starts_with(ann) {
+ return true;
+ }
+ }
+ false
+ }
+
+ fn parse_context_flags(&self, flags: &str) -> Vec<String> {
+ flags.split('|')
+ .map(|f| f.trim().to_string())
+ .filter(|f| !f.is_empty())
+ .collect()
+ }
+
+ fn error_name_to_code(&self, name: &str) -> i32 {
+ match name {
+ "EPERM" => -1,
+ "ENOENT" => -2,
+ "ESRCH" => -3,
+ "EINTR" => -4,
+ "EIO" => -5,
+ "ENXIO" => -6,
+ "E2BIG" => -7,
+ "ENOEXEC" => -8,
+ "EBADF" => -9,
+ "ECHILD" => -10,
+ "EAGAIN" | "EWOULDBLOCK" => -11,
+ "ENOMEM" => -12,
+ "EACCES" => -13,
+ "EFAULT" => -14,
+ "ENOTBLK" => -15,
+ "EBUSY" => -16,
+ "EEXIST" => -17,
+ "EXDEV" => -18,
+ "ENODEV" => -19,
+ "ENOTDIR" => -20,
+ "EISDIR" => -21,
+ "EINVAL" => -22,
+ "ENFILE" => -23,
+ "EMFILE" => -24,
+ "ENOTTY" => -25,
+ "ETXTBSY" => -26,
+ "EFBIG" => -27,
+ "ENOSPC" => -28,
+ "ESPIPE" => -29,
+ "EROFS" => -30,
+ "EMLINK" => -31,
+ "EPIPE" => -32,
+ "EDOM" => -33,
+ "ERANGE" => -34,
+ "EDEADLK" => -35,
+ "ENAMETOOLONG" => -36,
+ "ENOLCK" => -37,
+ "ENOSYS" => -38,
+ "ENOTEMPTY" => -39,
+ "ELOOP" => -40,
+ "ENOMSG" => -42,
+ "ENODATA" => -61,
+ "ENOLINK" => -67,
+ "EPROTO" => -71,
+ "EOVERFLOW" => -75,
+ "ELIBBAD" => -80,
+ "EILSEQ" => -84,
+ "ENOTSOCK" => -88,
+ "EDESTADDRREQ" => -89,
+ "EMSGSIZE" => -90,
+ "EPROTOTYPE" => -91,
+ "ENOPROTOOPT" => -92,
+ "EPROTONOSUPPORT" => -93,
+ "EOPNOTSUPP" | "ENOTSUP" => -95,
+ "EADDRINUSE" => -98,
+ "EADDRNOTAVAIL" => -99,
+ "ENETDOWN" => -100,
+ "ENETUNREACH" => -101,
+ "ENETRESET" => -102,
+ "ECONNABORTED" => -103,
+ "ECONNRESET" => -104,
+ "ENOBUFS" => -105,
+ "EISCONN" => -106,
+ "ENOTCONN" => -107,
+ "ETIMEDOUT" => -110,
+ "ECONNREFUSED" => -111,
+ "EALREADY" => -114,
+ "EINPROGRESS" => -115,
+ "ESTALE" => -116,
+ "EDQUOT" => -122,
+ "ENOMEDIUM" => -123,
+ "ENOKEY" => -126,
+ "ERESTARTSYS" => -512,
+ _ => 0,
+ }
+ }
+
+ fn parse_param_type(&self, type_str: &str) -> u32 {
+ match type_str {
+ "KAPI_TYPE_INT" => 1,
+ "KAPI_TYPE_UINT" => 2,
+ "KAPI_TYPE_LONG" => 3,
+ "KAPI_TYPE_ULONG" => 4,
+ "KAPI_TYPE_STRING" => 5,
+ "KAPI_TYPE_USER_PTR" => 6,
+ "KAPI_TYPE_PATH" => 5, // PATH is a string type
+ _ => 0,
+ }
+ }
+
+ fn parse_constraint_type(&self, type_str: &str) -> u32 {
+ match type_str {
+ "KAPI_CONSTRAINT_RANGE" => 1,
+ "KAPI_CONSTRAINT_MASK" => 2,
+ "KAPI_CONSTRAINT_ENUM" => 3,
+ "KAPI_CONSTRAINT_ALIGN" => 4,
+ "KAPI_CONSTRAINT_CUSTOM" => 5,
+ "KAPI_CONSTRAINT_STRLEN" => 6,
+ "KAPI_CONSTRAINT_NULLABLE" => 7,
+ "KAPI_CONSTRAINT_FD" => 8,
+ "KAPI_CONSTRAINT_USER_PATH" => 9,
+ "KAPI_CONSTRAINT_PID" => 10,
+ "KAPI_CONSTRAINT_BUFFER" => 11,
+ "KAPI_CONSTRAINT_IOCTL_CMD" => 12,
+ _ => 0,
+ }
+ }
+
+ fn parse_field_type(&self, type_str: &str) -> u32 {
+ match type_str {
+ "__s32" | "int" => 1,
+ "__u32" | "unsigned int" => 2,
+ "__s64" | "long" => 3,
+ "__u64" | "unsigned long" => 4,
+ _ => 0,
+ }
+ }
+
+ fn parse_param_flags(&self, flags: &str) -> u32 {
+ let mut result = 0;
+ for flag in flags.split('|') {
+ match flag.trim() {
+ "KAPI_PARAM_IN" | "IN" => result |= 1,
+ "KAPI_PARAM_OUT" | "OUT" => result |= 2,
+ "KAPI_PARAM_INOUT" | "INOUT" => result |= 3,
+ "KAPI_PARAM_USER" | "USER" => result |= 64,
+ _ => {}
+ }
+ }
+ result
+ }
+
+ fn parse_lock_type(&self, type_str: &str) -> u32 {
+ match type_str.trim() {
+ "KAPI_LOCK_SPINLOCK" => 0,
+ "KAPI_LOCK_MUTEX" => 1,
+ "KAPI_LOCK_RWLOCK" => 2,
+ "KAPI_LOCK_RCU" => 3,
+ _ => 3,
+ }
+ }
+
+ fn parse_signal_direction(&self, dir: &str) -> u32 {
+ match dir {
+ "KAPI_SIGNAL_RECEIVE" => 1,
+ "KAPI_SIGNAL_SEND" => 2,
+ "KAPI_SIGNAL_HANDLE" => 4,
+ "KAPI_SIGNAL_BLOCK" => 8,
+ "KAPI_SIGNAL_IGNORE" => 16,
+ _ => 0,
+ }
+ }
+
+ fn parse_signal_action(&self, action: &str) -> u32 {
+ match action {
+ "KAPI_SIGNAL_ACTION_DEFAULT" => 0,
+ "KAPI_SIGNAL_ACTION_TERMINATE" => 1,
+ "KAPI_SIGNAL_ACTION_COREDUMP" => 2,
+ "KAPI_SIGNAL_ACTION_STOP" => 3,
+ "KAPI_SIGNAL_ACTION_CONTINUE" => 4,
+ "KAPI_SIGNAL_ACTION_CUSTOM" => 5,
+ "KAPI_SIGNAL_ACTION_RETURN" => 6,
+ "KAPI_SIGNAL_ACTION_RESTART" => 7,
+ "KAPI_SIGNAL_ACTION_QUEUE" => 8,
+ "KAPI_SIGNAL_ACTION_DISCARD" => 9,
+ "KAPI_SIGNAL_ACTION_TRANSFORM" => 10,
+ _ => 0,
+ }
+ }
+
+ fn parse_signal_timing(&self, timing: &str) -> u32 {
+ match timing {
+ "KAPI_SIGNAL_TIME_BEFORE" => 0,
+ "KAPI_SIGNAL_TIME_DURING" => 1,
+ "KAPI_SIGNAL_TIME_AFTER" => 2,
+ _ => 0,
+ }
+ }
+
+ fn parse_signal_state(&self, state: &str) -> u32 {
+ match state {
+ "KAPI_SIGNAL_STATE_RUNNING" => 1,
+ "KAPI_SIGNAL_STATE_SLEEPING" => 2,
+ _ => 0,
+ }
+ }
+
+ fn parse_effect_type(&self, type_str: &str) -> u32 {
+ let mut result = 0;
+ for flag in type_str.split('|') {
+ match flag.trim() {
+ "KAPI_EFFECT_MODIFY_STATE" => result |= 1,
+ "KAPI_EFFECT_PROCESS_STATE" => result |= 2,
+ "KAPI_EFFECT_SCHEDULE" => result |= 4,
+ "KAPI_EFFECT_ALLOC_MEMORY" => result |= 128,
+ "KAPI_EFFECT_RESOURCE_CREATE" => result |= 1,
+ "KAPI_EFFECT_FILESYSTEM" => result |= 4096,
+ _ => {}
+ }
+ }
+ result
+ }
+
+ fn parse_capability_value(&self, cap: &str) -> i32 {
+ match cap {
+ "CAP_CHOWN" => 0,
+ "CAP_DAC_OVERRIDE" => 1,
+ "CAP_DAC_READ_SEARCH" => 2,
+ "CAP_FOWNER" => 3,
+ "CAP_FSETID" => 4,
+ "CAP_KILL" => 5,
+ "CAP_SETGID" => 6,
+ "CAP_SETUID" => 7,
+ "CAP_SETPCAP" => 8,
+ "CAP_LINUX_IMMUTABLE" => 9,
+ "CAP_NET_BIND_SERVICE" => 10,
+ "CAP_NET_BROADCAST" => 11,
+ "CAP_NET_ADMIN" => 12,
+ "CAP_NET_RAW" => 13,
+ "CAP_IPC_LOCK" => 14,
+ "CAP_IPC_OWNER" => 15,
+ "CAP_SYS_MODULE" => 16,
+ "CAP_SYS_RAWIO" => 17,
+ "CAP_SYS_CHROOT" => 18,
+ "CAP_SYS_PTRACE" => 19,
+ "CAP_SYS_PACCT" => 20,
+ "CAP_SYS_ADMIN" => 21,
+ "CAP_SYS_BOOT" => 22,
+ "CAP_SYS_NICE" => 23,
+ "CAP_SYS_RESOURCE" => 24,
+ "CAP_SYS_TIME" => 25,
+ "CAP_SYS_TTY_CONFIG" => 26,
+ "CAP_MKNOD" => 27,
+ "CAP_LEASE" => 28,
+ "CAP_AUDIT_WRITE" => 29,
+ "CAP_AUDIT_CONTROL" => 30,
+ "CAP_SETFCAP" => 31,
+ "CAP_MAC_OVERRIDE" => 32,
+ "CAP_MAC_ADMIN" => 33,
+ "CAP_SYSLOG" => 34,
+ "CAP_WAKE_ALARM" => 35,
+ "CAP_BLOCK_SUSPEND" => 36,
+ "CAP_AUDIT_READ" => 37,
+ "CAP_PERFMON" => 38,
+ "CAP_BPF" => 39,
+ "CAP_CHECKPOINT_RESTORE" => 40,
+ _ => 0,
+ }
+ }
+
+ fn parse_return_check_type(&self, check: &str) -> u32 {
+ match check {
+ "KAPI_RETURN_ERROR_CHECK" => 1,
+ "KAPI_RETURN_SUCCESS_CHECK" => 2,
+ "KAPI_RETURN_FD" => 3,
+ _ => 0,
+ }
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ fn parser() -> KerneldocParserImpl {
+ KerneldocParserImpl::new()
+ }
+
+ #[test]
+ fn parse_minimal_kerneldoc() {
+ let doc = "\
+sys_foo - Do something useful
+context-flags: KAPI_CTX_PROCESS
+param-count: 1
+@fd: The file descriptor
+param-type: fd, KAPI_TYPE_INT
+error: EBADF, Bad file descriptor
+";
+ let spec = parser()
+ .parse_kerneldoc(doc, "sys_foo", "syscall", None)
+ .unwrap();
+
+ assert_eq!(spec.name, "sys_foo");
+ assert_eq!(spec.api_type, "syscall");
+ assert_eq!(spec.description.as_deref(), Some("Do something useful"));
+ assert_eq!(spec.param_count, Some(1));
+ assert_eq!(spec.parameters.len(), 1);
+ assert_eq!(spec.parameters[0].name, "fd");
+ assert_eq!(spec.parameters[0].description, "The file descriptor");
+ assert_eq!(spec.parameters[0].param_type, 1); // KAPI_TYPE_INT
+ assert_eq!(spec.errors.len(), 1);
+ assert_eq!(spec.errors[0].name, "EBADF");
+ assert_eq!(spec.errors[0].error_code, -9);
+ }
+
+ #[test]
+ fn parse_multiple_param_types() {
+ let doc = "\
+sys_bar - Multiple params
+@fd: file descriptor arg
+@buf: user buffer
+@count: byte count
+@flags: option flags
+param-type: fd, KAPI_TYPE_INT
+param-type: buf, KAPI_TYPE_USER_PTR
+param-type: count, KAPI_TYPE_UINT
+param-type: flags, KAPI_TYPE_ULONG
+";
+ let sig = "(bar, int, fd, char __user *, buf, size_t, count, unsigned long, flags)";
+ let spec = parser()
+ .parse_kerneldoc(doc, "sys_bar", "syscall", Some(sig))
+ .unwrap();
+
+ assert_eq!(spec.parameters.len(), 4);
+
+ let fd_param = spec.parameters.iter().find(|p| p.name == "fd").unwrap();
+ assert_eq!(fd_param.param_type, 1); // INT
+
+ let buf_param = spec.parameters.iter().find(|p| p.name == "buf").unwrap();
+ assert_eq!(buf_param.param_type, 6); // USER_PTR
+ assert_eq!(buf_param.type_name, "char __user * buf");
+
+ let count_param = spec.parameters.iter().find(|p| p.name == "count").unwrap();
+ assert_eq!(count_param.param_type, 2); // UINT
+
+ let flags_param = spec.parameters.iter().find(|p| p.name == "flags").unwrap();
+ assert_eq!(flags_param.param_type, 4); // ULONG
+ }
+
+ #[test]
+ fn parse_error_codes_with_descriptions() {
+ let doc = "\
+sys_err - Error test
+error: EBADF
+ desc: Bad file descriptor
+ condition: fd < 0
+error: EFAULT
+ desc: Bad user pointer
+ condition: buf is NULL
+error: EINVAL
+ desc: Invalid argument
+";
+ let spec = parser()
+ .parse_kerneldoc(doc, "sys_err", "syscall", None)
+ .unwrap();
+
+ assert_eq!(spec.errors.len(), 3);
+
+ assert_eq!(spec.errors[0].name, "EBADF");
+ assert_eq!(spec.errors[0].error_code, -9);
+ assert_eq!(spec.errors[0].description, "Bad file descriptor");
+ assert_eq!(spec.errors[0].condition, "fd < 0");
+
+ assert_eq!(spec.errors[1].name, "EFAULT");
+ assert_eq!(spec.errors[1].error_code, -14);
+ assert_eq!(spec.errors[1].description, "Bad user pointer");
+
+ assert_eq!(spec.errors[2].name, "EINVAL");
+ assert_eq!(spec.errors[2].error_code, -22);
+ assert_eq!(spec.errors[2].description, "Invalid argument");
+ }
+
+ #[test]
+ fn parse_context_flags() {
+ let doc = "\
+sys_ctx - Context test
+context-flags: KAPI_CTX_PROCESS|KAPI_CTX_SLEEPABLE
+";
+ let spec = parser()
+ .parse_kerneldoc(doc, "sys_ctx", "syscall", None)
+ .unwrap();
+
+ assert_eq!(spec.context_flags.len(), 2);
+ assert_eq!(spec.context_flags[0], "KAPI_CTX_PROCESS");
+ assert_eq!(spec.context_flags[1], "KAPI_CTX_SLEEPABLE");
+ }
+
+ #[test]
+ fn parse_capability_block() {
+ let doc = "\
+sys_cap - Capability test
+capability: CAP_SYS_ADMIN
+ type: required
+ allows: Full system administration
+ without: Operation not permitted
+ condition: always
+ priority: 5
+";
+ let spec = parser()
+ .parse_kerneldoc(doc, "sys_cap", "syscall", None)
+ .unwrap();
+
+ assert_eq!(spec.capabilities.len(), 1);
+ let cap = &spec.capabilities[0];
+ assert_eq!(cap.capability, 21); // CAP_SYS_ADMIN
+ assert_eq!(cap.action, "required");
+ assert_eq!(cap.allows, "Full system administration");
+ assert_eq!(cap.without_cap, "Operation not permitted");
+ assert_eq!(cap.check_condition.as_deref(), Some("always"));
+ assert_eq!(cap.priority, Some(5));
+ }
+
+ #[test]
+ fn parse_lock_block() {
+ let doc = "\
+sys_lock - Lock test
+lock: files_lock, KAPI_LOCK_MUTEX
+ scope: acquires
+ desc: Protects file table
+";
+ let spec = parser()
+ .parse_kerneldoc(doc, "sys_lock", "syscall", None)
+ .unwrap();
+
+ assert_eq!(spec.locks.len(), 1);
+ let lock = &spec.locks[0];
+ assert_eq!(lock.lock_name, "files_lock");
+ assert_eq!(lock.lock_type, 1); // MUTEX
+ assert_eq!(lock.scope, super::super::KAPI_LOCK_ACQUIRES);
+ assert_eq!(lock.description, "Protects file table");
+ }
+
+ #[test]
+ fn parse_signal_block() {
+ let doc = "\
+sys_sig - Signal test
+signal: SIGKILL
+ direction: KAPI_SIGNAL_RECEIVE
+ action: KAPI_SIGNAL_ACTION_TERMINATE
+ timing: KAPI_SIGNAL_TIME_DURING
+ priority: 3
+ restartable: yes
+ interruptible: yes
+ desc: Process termination signal
+";
+ let spec = parser()
+ .parse_kerneldoc(doc, "sys_sig", "syscall", None)
+ .unwrap();
+
+ assert_eq!(spec.signals.len(), 1);
+ let sig = &spec.signals[0];
+ assert_eq!(sig.signal_name, "SIGKILL");
+ assert_eq!(sig.direction, 1); // RECEIVE
+ assert_eq!(sig.action, 1); // TERMINATE
+ assert_eq!(sig.timing, 1); // DURING
+ assert_eq!(sig.priority, 3);
+ assert!(sig.restartable);
+ assert!(sig.interruptible);
+ assert_eq!(sig.description.as_deref(), Some("Process termination signal"));
+ }
+
+ #[test]
+ fn parse_side_effect_flat() {
+ let doc = "\
+sys_se - Side effect test
+side-effect: KAPI_EFFECT_MODIFY_STATE, file_table, Allocates a new file descriptor
+";
+ let spec = parser()
+ .parse_kerneldoc(doc, "sys_se", "syscall", None)
+ .unwrap();
+
+ assert_eq!(spec.side_effects.len(), 1);
+ let se = &spec.side_effects[0];
+ assert_eq!(se.effect_type, 1); // MODIFY_STATE
+ assert_eq!(se.target, "file_table");
+ assert_eq!(se.description, "Allocates a new file descriptor");
+ }
+
+ #[test]
+ fn parse_side_effect_block() {
+ let doc = "\
+sys_se2 - Side effect block test
+side-effect: KAPI_EFFECT_ALLOC_MEMORY
+ target: kernel_heap
+ desc: Allocates kernel memory
+ reversible: yes
+ condition: size > 0
+";
+ let spec = parser()
+ .parse_kerneldoc(doc, "sys_se2", "syscall", None)
+ .unwrap();
+
+ assert_eq!(spec.side_effects.len(), 1);
+ let se = &spec.side_effects[0];
+ assert_eq!(se.effect_type, 128); // ALLOC_MEMORY
+ assert_eq!(se.target, "kernel_heap");
+ assert_eq!(se.description, "Allocates kernel memory");
+ assert!(se.reversible);
+ assert_eq!(se.condition.as_deref(), Some("size > 0"));
+ }
+
+ #[test]
+ fn parse_empty_doc_no_error() {
+ let doc = "";
+ let spec = parser()
+ .parse_kerneldoc(doc, "sys_empty", "syscall", None)
+ .unwrap();
+
+ assert_eq!(spec.name, "sys_empty");
+ assert!(spec.description.is_none());
+ assert!(spec.parameters.is_empty());
+ assert!(spec.errors.is_empty());
+ assert!(spec.signals.is_empty());
+ assert!(spec.capabilities.is_empty());
+ assert!(spec.locks.is_empty());
+ assert!(spec.side_effects.is_empty());
+ assert!(spec.context_flags.is_empty());
+ }
+
+ #[test]
+ fn parse_missing_sections_no_error() {
+ // Only has a description, no KAPI annotations
+ let doc = "\
+sys_simple - Just a simple syscall
+";
+ let spec = parser()
+ .parse_kerneldoc(doc, "sys_simple", "syscall", None)
+ .unwrap();
+
+ assert_eq!(spec.description.as_deref(), Some("Just a simple syscall"));
+ assert!(spec.parameters.is_empty());
+ assert!(spec.errors.is_empty());
+ assert!(spec.context_flags.is_empty());
+ }
+
+ #[test]
+ fn parse_constraint_block() {
+ let doc = "\
+sys_cst - Constraint test
+constraint: valid_fd
+ desc: File descriptor must be valid and open
+ expr: fd >= 0 && fd < NR_OPEN
+";
+ let spec = parser()
+ .parse_kerneldoc(doc, "sys_cst", "syscall", None)
+ .unwrap();
+
+ assert_eq!(spec.constraints.len(), 1);
+ let cst = &spec.constraints[0];
+ assert_eq!(cst.name, "valid_fd");
+ assert_eq!(cst.description, "File descriptor must be valid and open");
+ assert_eq!(cst.expression.as_deref(), Some("fd >= 0 && fd < NR_OPEN"));
+ }
+
+ #[test]
+ fn parse_state_transition_flat() {
+ let doc = "\
+sys_st - State transition test
+state-trans: fd, open, closed, File descriptor is closed
+";
+ let spec = parser()
+ .parse_kerneldoc(doc, "sys_st", "syscall", None)
+ .unwrap();
+
+ assert_eq!(spec.state_transitions.len(), 1);
+ let st = &spec.state_transitions[0];
+ assert_eq!(st.object, "fd");
+ assert_eq!(st.from_state, "open");
+ assert_eq!(st.to_state, "closed");
+ assert_eq!(st.description, "File descriptor is closed");
+ }
+
+ #[test]
+ fn parse_param_block_with_range() {
+ let doc = "\
+sys_rng - Range test
+@count: byte count
+param: count
+ type: KAPI_TYPE_UINT
+ flags: IN
+ range: 0, 4096
+ constraint-type: KAPI_CONSTRAINT_RANGE
+";
+ let spec = parser()
+ .parse_kerneldoc(doc, "sys_rng", "syscall", None)
+ .unwrap();
+
+ assert_eq!(spec.parameters.len(), 1);
+ let p = &spec.parameters[0];
+ assert_eq!(p.name, "count");
+ assert_eq!(p.param_type, 2); // UINT
+ assert_eq!(p.flags, 1); // IN
+ assert_eq!(p.min_value, Some(0));
+ assert_eq!(p.max_value, Some(4096));
+ assert_eq!(p.constraint_type, 1); // RANGE
+ }
+
+ #[test]
+ fn parse_return_block() {
+ let doc = "\
+sys_ret - Return test
+return:
+ type: KAPI_TYPE_INT
+ check-type: KAPI_RETURN_FD
+ success: 0
+ desc: Returns file descriptor on success
+";
+ let spec = parser()
+ .parse_kerneldoc(doc, "sys_ret", "syscall", None)
+ .unwrap();
+
+ let ret = spec.return_spec.as_ref().unwrap();
+ assert_eq!(ret.type_name, "KAPI_TYPE_INT");
+ assert_eq!(ret.return_type, 1); // INT
+ assert_eq!(ret.check_type, 3); // FD
+ assert_eq!(ret.success_value, Some(0));
+ assert_eq!(ret.description, "Returns file descriptor on success");
+ }
+}
diff --git a/tools/kapi/src/extractor/mod.rs b/tools/kapi/src/extractor/mod.rs
new file mode 100644
index 0000000000000..46a8eb11b87b9
--- /dev/null
+++ b/tools/kapi/src/extractor/mod.rs
@@ -0,0 +1,461 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2026 Sasha Levin <sashal@kernel.org>
+
+use crate::formatter::OutputFormatter;
+use anyhow::Result;
+use std::io::Write;
+
+pub mod debugfs;
+pub mod kerneldoc_parser;
+pub mod source_parser;
+pub mod vmlinux;
+
+pub use debugfs::DebugfsExtractor;
+pub use source_parser::SourceExtractor;
+pub use vmlinux::VmlinuxExtractor;
+
+/// Socket state specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct SocketStateSpec {
+ pub required_states: Vec<String>,
+ pub forbidden_states: Vec<String>,
+ pub resulting_state: Option<String>,
+ pub condition: Option<String>,
+ pub applicable_protocols: Option<String>,
+}
+
+/// Protocol behavior specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct ProtocolBehaviorSpec {
+ pub applicable_protocols: String,
+ pub behavior: String,
+ pub protocol_flags: Option<String>,
+ pub flag_description: Option<String>,
+}
+
+/// Address family specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct AddrFamilySpec {
+ pub family: i32,
+ pub family_name: String,
+ pub addr_struct_size: usize,
+ pub min_addr_len: usize,
+ pub max_addr_len: usize,
+ pub addr_format: Option<String>,
+ pub supports_wildcard: bool,
+ pub supports_multicast: bool,
+ pub supports_broadcast: bool,
+ pub special_addresses: Option<String>,
+ pub port_range_min: u32,
+ pub port_range_max: u32,
+}
+
+/// Buffer specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct BufferSpec {
+ pub buffer_behaviors: Option<String>,
+ pub min_buffer_size: Option<usize>,
+ pub max_buffer_size: Option<usize>,
+ pub optimal_buffer_size: Option<usize>,
+}
+
+/// Async specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct AsyncSpec {
+ pub supported_modes: Option<String>,
+ pub nonblock_errno: Option<i32>,
+}
+
+/// Capability specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct CapabilitySpec {
+ pub capability: i32,
+ pub name: String,
+ pub action: String,
+ pub allows: String,
+ pub without_cap: String,
+ pub check_condition: Option<String>,
+ pub priority: Option<u8>,
+ pub alternatives: Vec<i32>,
+}
+
+/// Parameter specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct ParamSpec {
+ pub index: u32,
+ pub name: String,
+ pub type_name: String,
+ pub description: String,
+ pub flags: u32,
+ pub param_type: u32,
+ pub constraint_type: u32,
+ pub constraint: Option<String>,
+ pub min_value: Option<i64>,
+ pub max_value: Option<i64>,
+ pub valid_mask: Option<u64>,
+ pub enum_values: Vec<String>,
+ pub size: Option<u32>,
+ pub alignment: Option<u32>,
+}
+
+/// Return value specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct ReturnSpec {
+ pub type_name: String,
+ pub description: String,
+ pub return_type: u32,
+ pub check_type: u32,
+ pub success_value: Option<i64>,
+ pub success_min: Option<i64>,
+ pub success_max: Option<i64>,
+ pub error_values: Vec<i32>,
+}
+
+/// Error specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct ErrorSpec {
+ pub error_code: i32,
+ pub name: String,
+ pub condition: String,
+ pub description: String,
+}
+
+/// Signal specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct SignalSpec {
+ pub signal_num: i32,
+ pub signal_name: String,
+ pub direction: u32,
+ pub action: u32,
+ pub target: Option<String>,
+ pub condition: Option<String>,
+ pub description: Option<String>,
+ pub timing: u32,
+ pub priority: u32,
+ pub restartable: bool,
+ pub interruptible: bool,
+ pub queue: Option<String>,
+ pub sa_flags: u32,
+ pub sa_flags_required: u32,
+ pub sa_flags_forbidden: u32,
+ pub state_required: u32,
+ pub state_forbidden: u32,
+ pub error_on_signal: Option<i32>,
+}
+
+/// Signal mask specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct SignalMaskSpec {
+ pub name: String,
+ pub description: String,
+}
+
+/// Side effect specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct SideEffectSpec {
+ pub effect_type: u32,
+ pub target: String,
+ pub condition: Option<String>,
+ pub description: String,
+ pub reversible: bool,
+}
+
+/// State transition specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct StateTransitionSpec {
+ pub object: String,
+ pub from_state: String,
+ pub to_state: String,
+ pub condition: Option<String>,
+ pub description: String,
+}
+
+/// Constraint specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct ConstraintSpec {
+ pub name: String,
+ pub description: String,
+ pub expression: Option<String>,
+}
+
+/// Lock scope enum values matching kernel enum kapi_lock_scope
+pub const KAPI_LOCK_INTERNAL: u32 = 0;
+pub const KAPI_LOCK_ACQUIRES: u32 = 1;
+pub const KAPI_LOCK_RELEASES: u32 = 2;
+pub const KAPI_LOCK_CALLER_HELD: u32 = 3;
+
+/// Lock specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct LockSpec {
+ pub lock_name: String,
+ pub lock_type: u32,
+ pub scope: u32,
+ pub description: String,
+}
+
+/// Struct field specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct StructFieldSpec {
+ pub name: String,
+ pub field_type: u32,
+ pub type_name: String,
+ pub offset: usize,
+ pub size: usize,
+ pub flags: u32,
+ pub constraint_type: u32,
+ pub min_value: i64,
+ pub max_value: i64,
+ pub valid_mask: u64,
+ pub description: String,
+}
+
+/// Struct specification
+#[derive(Debug, Clone, serde::Serialize)]
+pub struct StructSpec {
+ pub name: String,
+ pub size: usize,
+ pub alignment: usize,
+ pub field_count: u32,
+ pub fields: Vec<StructFieldSpec>,
+ pub description: String,
+}
+
+/// Common API specification information that all extractors should provide
+#[derive(Debug, Clone, Default)]
+pub struct ApiSpec {
+ pub name: String,
+ pub api_type: String,
+ pub description: Option<String>,
+ pub long_description: Option<String>,
+ pub version: Option<String>,
+ pub context_flags: Vec<String>,
+ pub param_count: Option<u32>,
+ pub error_count: Option<u32>,
+ pub examples: Option<String>,
+ pub notes: Option<String>,
+ // Sysfs-specific fields
+ pub subsystem: Option<String>,
+ pub sysfs_path: Option<String>,
+ pub permissions: Option<String>,
+ // Networking-specific fields
+ pub socket_state: Option<SocketStateSpec>,
+ pub protocol_behaviors: Vec<ProtocolBehaviorSpec>,
+ pub addr_families: Vec<AddrFamilySpec>,
+ pub buffer_spec: Option<BufferSpec>,
+ pub async_spec: Option<AsyncSpec>,
+ pub net_data_transfer: Option<String>,
+ pub capabilities: Vec<CapabilitySpec>,
+ pub parameters: Vec<ParamSpec>,
+ pub return_spec: Option<ReturnSpec>,
+ pub errors: Vec<ErrorSpec>,
+ pub signals: Vec<SignalSpec>,
+ pub signal_masks: Vec<SignalMaskSpec>,
+ pub side_effects: Vec<SideEffectSpec>,
+ pub state_transitions: Vec<StateTransitionSpec>,
+ pub constraints: Vec<ConstraintSpec>,
+ pub locks: Vec<LockSpec>,
+ pub struct_specs: Vec<StructSpec>,
+}
+
+/// Trait for extracting API specifications from different sources
+pub trait ApiExtractor {
+ /// Extract all API specifications from the source
+ fn extract_all(&self) -> Result<Vec<ApiSpec>>;
+
+ /// Extract a specific API specification by name
+ fn extract_by_name(&self, name: &str) -> Result<Option<ApiSpec>>;
+
+ /// Display detailed information about a specific API
+ fn display_api_details(
+ &self,
+ api_name: &str,
+ formatter: &mut dyn OutputFormatter,
+ writer: &mut dyn Write,
+ ) -> Result<()>;
+}
+
+/// Helper function to display an ApiSpec using a formatter
+pub fn display_api_spec(
+ spec: &ApiSpec,
+ formatter: &mut dyn OutputFormatter,
+ writer: &mut dyn Write,
+) -> Result<()> {
+ formatter.begin_api_details(writer, &spec.name)?;
+
+ if let Some(desc) = &spec.description {
+ formatter.description(writer, desc)?;
+ }
+
+ if let Some(long_desc) = &spec.long_description {
+ formatter.long_description(writer, long_desc)?;
+ }
+
+ if !spec.context_flags.is_empty() {
+ formatter.begin_context_flags(writer)?;
+ for flag in &spec.context_flags {
+ formatter.context_flag(writer, flag)?;
+ }
+ formatter.end_context_flags(writer)?;
+ }
+
+ if !spec.parameters.is_empty() {
+ formatter.begin_parameters(writer, spec.parameters.len().try_into().unwrap_or(u32::MAX))?;
+ for param in &spec.parameters {
+ formatter.parameter(writer, param)?;
+ }
+ formatter.end_parameters(writer)?;
+ }
+
+ if let Some(ret) = &spec.return_spec {
+ formatter.return_spec(writer, ret)?;
+ }
+
+ if !spec.errors.is_empty() {
+ formatter.begin_errors(writer, spec.errors.len().try_into().unwrap_or(u32::MAX))?;
+ for error in &spec.errors {
+ formatter.error(writer, error)?;
+ }
+ formatter.end_errors(writer)?;
+ }
+
+ if let Some(notes) = &spec.notes {
+ formatter.notes(writer, notes)?;
+ }
+
+ if let Some(examples) = &spec.examples {
+ formatter.examples(writer, examples)?;
+ }
+
+ // Display sysfs-specific fields
+ if spec.api_type == "sysfs" {
+ if let Some(subsystem) = &spec.subsystem {
+ formatter.sysfs_subsystem(writer, subsystem)?;
+ }
+ if let Some(path) = &spec.sysfs_path {
+ formatter.sysfs_path(writer, path)?;
+ }
+ if let Some(perms) = &spec.permissions {
+ formatter.sysfs_permissions(writer, perms)?;
+ }
+ }
+
+ // Display networking-specific fields
+ if let Some(socket_state) = &spec.socket_state {
+ formatter.socket_state(writer, socket_state)?;
+ }
+
+ if !spec.protocol_behaviors.is_empty() {
+ formatter.begin_protocol_behaviors(writer)?;
+ for behavior in &spec.protocol_behaviors {
+ formatter.protocol_behavior(writer, behavior)?;
+ }
+ formatter.end_protocol_behaviors(writer)?;
+ }
+
+ if !spec.addr_families.is_empty() {
+ formatter.begin_addr_families(writer)?;
+ for family in &spec.addr_families {
+ formatter.addr_family(writer, family)?;
+ }
+ formatter.end_addr_families(writer)?;
+ }
+
+ if let Some(buffer_spec) = &spec.buffer_spec {
+ formatter.buffer_spec(writer, buffer_spec)?;
+ }
+
+ if let Some(async_spec) = &spec.async_spec {
+ formatter.async_spec(writer, async_spec)?;
+ }
+
+ if let Some(net_data_transfer) = &spec.net_data_transfer {
+ formatter.net_data_transfer(writer, net_data_transfer)?;
+ }
+
+ if !spec.capabilities.is_empty() {
+ formatter.begin_capabilities(writer)?;
+ for cap in &spec.capabilities {
+ formatter.capability(writer, cap)?;
+ }
+ formatter.end_capabilities(writer)?;
+ }
+
+ // Display signals
+ if !spec.signals.is_empty() {
+ formatter.begin_signals(writer, spec.signals.len().try_into().unwrap_or(u32::MAX))?;
+ for signal in &spec.signals {
+ formatter.signal(writer, signal)?;
+ }
+ formatter.end_signals(writer)?;
+ }
+
+ // Display signal masks
+ if !spec.signal_masks.is_empty() {
+ formatter.begin_signal_masks(
+ writer,
+ spec.signal_masks.len().try_into().unwrap_or(u32::MAX),
+ )?;
+ for mask in &spec.signal_masks {
+ formatter.signal_mask(writer, mask)?;
+ }
+ formatter.end_signal_masks(writer)?;
+ }
+
+ // Display side effects
+ if !spec.side_effects.is_empty() {
+ formatter.begin_side_effects(
+ writer,
+ spec.side_effects.len().try_into().unwrap_or(u32::MAX),
+ )?;
+ for effect in &spec.side_effects {
+ formatter.side_effect(writer, effect)?;
+ }
+ formatter.end_side_effects(writer)?;
+ }
+
+ // Display state transitions
+ if !spec.state_transitions.is_empty() {
+ formatter.begin_state_transitions(
+ writer,
+ spec.state_transitions.len().try_into().unwrap_or(u32::MAX),
+ )?;
+ for trans in &spec.state_transitions {
+ formatter.state_transition(writer, trans)?;
+ }
+ formatter.end_state_transitions(writer)?;
+ }
+
+ // Display constraints
+ if !spec.constraints.is_empty() {
+ formatter.begin_constraints(
+ writer,
+ spec.constraints.len().try_into().unwrap_or(u32::MAX),
+ )?;
+ for constraint in &spec.constraints {
+ formatter.constraint(writer, constraint)?;
+ }
+ formatter.end_constraints(writer)?;
+ }
+
+ // Display locks
+ if !spec.locks.is_empty() {
+ formatter.begin_locks(writer, spec.locks.len().try_into().unwrap_or(u32::MAX))?;
+ for lock in &spec.locks {
+ formatter.lock(writer, lock)?;
+ }
+ formatter.end_locks(writer)?;
+ }
+
+ // Display struct specs
+ if !spec.struct_specs.is_empty() {
+ formatter.begin_struct_specs(writer, spec.struct_specs.len().try_into().unwrap_or(u32::MAX))?;
+ for struct_spec in &spec.struct_specs {
+ formatter.struct_spec(writer, struct_spec)?;
+ }
+ formatter.end_struct_specs(writer)?;
+ }
+
+ formatter.end_api_details(writer)?;
+
+ Ok(())
+}
diff --git a/tools/kapi/src/extractor/source_parser.rs b/tools/kapi/src/extractor/source_parser.rs
new file mode 100644
index 0000000000000..5d660847a78ff
--- /dev/null
+++ b/tools/kapi/src/extractor/source_parser.rs
@@ -0,0 +1,408 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2026 Sasha Levin <sashal@kernel.org>
+
+use super::{
+ ApiExtractor, ApiSpec, display_api_spec,
+};
+use super::kerneldoc_parser::KerneldocParserImpl;
+use crate::formatter::OutputFormatter;
+use anyhow::{Context, Result};
+use regex::Regex;
+use std::fs;
+use std::io::Write;
+use std::path::Path;
+use walkdir::WalkDir;
+
+/// Extractor for kernel source files with KAPI-annotated kerneldoc
+pub struct SourceExtractor {
+ path: String,
+ parser: KerneldocParserImpl,
+ syscall_regex: Regex,
+ ioctl_regex: Regex,
+ function_regex: Regex,
+}
+
+impl SourceExtractor {
+ pub fn new(path: &str) -> Result<Self> {
+ Ok(SourceExtractor {
+ path: path.to_string(),
+ parser: KerneldocParserImpl::new(),
+ syscall_regex: Regex::new(r"SYSCALL_DEFINE\d+\((\w+)")?,
+ ioctl_regex: Regex::new(r"(?:static\s+)?long\s+(\w+_ioctl)\s*\(")?,
+ function_regex: Regex::new(
+ r"(?m)^(?:static\s+)?(?:inline\s+)?(?:(?:unsigned\s+)?(?:long|int|void|char|short|struct\s+\w+\s*\*?|[\w_]+_t)\s*\*?\s+)?(\w+)\s*\([^)]*\)",
+ )?,
+ })
+ }
+
+ fn extract_from_file(&self, path: &Path) -> Result<Vec<ApiSpec>> {
+ let content = fs::read_to_string(path)
+ .with_context(|| format!("Failed to read file: {}", path.display()))?;
+
+ self.extract_from_content(&content)
+ }
+
+ fn extract_from_content(&self, content: &str) -> Result<Vec<ApiSpec>> {
+ let mut specs = Vec::new();
+ let mut in_kerneldoc = false;
+ let mut current_doc = String::new();
+ let lines: Vec<&str> = content.lines().collect();
+ let mut i = 0;
+
+ while i < lines.len() {
+ let line = lines[i];
+
+ // Start of kerneldoc comment
+ if line.trim_start().starts_with("/**") {
+ in_kerneldoc = true;
+ current_doc.clear();
+ i += 1;
+ continue;
+ }
+
+ // Inside kerneldoc comment
+ if in_kerneldoc {
+ if line.contains("*/") {
+ in_kerneldoc = false;
+
+ // Check if this kerneldoc has KAPI annotations
+ if current_doc.contains("context-flags:") ||
+ current_doc.contains("param-count:") ||
+ current_doc.contains("side-effect:") ||
+ current_doc.contains("state-trans:") ||
+ current_doc.contains("error-code:") {
+
+ // Look ahead for the function declaration
+ if let Some((name, api_type, signature)) = self.find_function_after(&lines, i + 1) {
+ if let Ok(spec) = self.parser.parse_kerneldoc(&current_doc, &name, &api_type, Some(&signature)) {
+ specs.push(spec);
+ }
+ }
+ }
+ } else {
+ // Remove leading asterisk and preserve content
+ let cleaned = if let Some(stripped) = line.trim_start().strip_prefix("*") {
+ if let Some(no_space) = stripped.strip_prefix(' ') {
+ no_space
+ } else {
+ stripped
+ }
+ } else {
+ line.trim_start()
+ };
+ current_doc.push_str(cleaned);
+ current_doc.push('\n');
+ }
+ }
+
+ i += 1;
+ }
+
+ Ok(specs)
+ }
+
+ fn find_function_after(&self, lines: &[&str], start: usize) -> Option<(String, String, String)> {
+ for i in start..lines.len().min(start + 10) {
+ let line = lines[i];
+
+ // Skip empty lines
+ if line.trim().is_empty() {
+ continue;
+ }
+
+ // Check for SYSCALL_DEFINE
+ if let Some(caps) = self.syscall_regex.captures(line) {
+ let name = format!("sys_{}", caps.get(1).unwrap().as_str());
+ let signature = self.extract_syscall_signature(lines, i);
+ return Some((name, "syscall".to_string(), signature));
+ }
+
+ // Check for ioctl function
+ if let Some(caps) = self.ioctl_regex.captures(line) {
+ let name = caps.get(1).unwrap().as_str().to_string();
+ return Some((name, "ioctl".to_string(), line.to_string()));
+ }
+
+ // Check for regular function
+ if let Some(caps) = self.function_regex.captures(line) {
+ let name = caps.get(1).unwrap().as_str().to_string();
+ return Some((name, "function".to_string(), line.to_string()));
+ }
+
+ // Stop if we hit something that's clearly not part of the function declaration
+ if !line.starts_with(' ') && !line.starts_with('\t') && !line.trim().is_empty() {
+ break;
+ }
+ }
+
+ None
+ }
+
+ fn extract_syscall_signature(&self, lines: &[&str], start: usize) -> String {
+ // Extract the full SYSCALL_DEFINE signature
+ let mut sig = String::new();
+ let mut in_paren = false;
+ let mut paren_count = 0;
+
+ for line in lines.iter().skip(start).take(20) {
+ let line = *line;
+
+ // Start of SYSCALL_DEFINE
+ if line.contains("SYSCALL_DEFINE") {
+ if let Some(pos) = line.find('(') {
+ sig.push_str(&line[pos..]);
+ in_paren = true;
+ paren_count = line[pos..].chars().filter(|&c| c == '(').count() -
+ line[pos..].chars().filter(|&c| c == ')').count();
+ }
+ } else if in_paren {
+ sig.push(' ');
+ sig.push_str(line.trim());
+ paren_count += line.chars().filter(|&c| c == '(').count();
+ paren_count = paren_count.saturating_sub(line.chars().filter(|&c| c == ')').count());
+
+ if paren_count == 0 {
+ break;
+ }
+ }
+ }
+
+ sig
+ }
+}
+
+impl ApiExtractor for SourceExtractor {
+ fn extract_all(&self) -> Result<Vec<ApiSpec>> {
+ let path = Path::new(&self.path);
+ let mut all_specs = Vec::new();
+
+ if path.is_file() {
+ // Single file
+ all_specs.extend(self.extract_from_file(path)?);
+ } else if path.is_dir() {
+ // Directory - walk all .c files
+ for entry in WalkDir::new(path)
+ .into_iter()
+ .filter_map(|e| e.ok())
+ .filter(|e| e.path().extension().is_some_and(|ext| ext == "c" || ext == "h"))
+ {
+ match self.extract_from_file(entry.path()) {
+ Ok(specs) => all_specs.extend(specs),
+ Err(e) => {
+ eprintln!("Warning: failed to parse {}: {}", entry.path().display(), e);
+ }
+ }
+ }
+ }
+
+ Ok(all_specs)
+ }
+
+ fn extract_by_name(&self, name: &str) -> Result<Option<ApiSpec>> {
+ let all_specs = self.extract_all()?;
+ Ok(all_specs.into_iter().find(|s| s.name == name))
+ }
+
+ fn display_api_details(
+ &self,
+ api_name: &str,
+ formatter: &mut dyn OutputFormatter,
+ output: &mut dyn Write,
+ ) -> Result<()> {
+ if let Some(spec) = self.extract_by_name(api_name)? {
+ display_api_spec(&spec, formatter, output)?;
+ } else {
+ writeln!(output, "API '{}' not found", api_name)?;
+ }
+ Ok(())
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ fn make_extractor() -> SourceExtractor {
+ SourceExtractor::new("/dev/null").unwrap()
+ }
+
+ #[test]
+ fn detect_syscall_define3() {
+ let content = r#"
+/**
+ * sys_open - open a file
+ * context-flags: KAPI_CTX_PROCESS
+ * param-count: 3
+ * @filename: pathname to open
+ * param-type: filename, KAPI_TYPE_STRING
+ * error-code: ENOENT
+ */
+SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
+{
+ return 0;
+}
+"#;
+ let ext = make_extractor();
+ let specs = ext.extract_from_content(content).unwrap();
+ assert_eq!(specs.len(), 1);
+ assert_eq!(specs[0].name, "sys_open");
+ assert_eq!(specs[0].api_type, "syscall");
+ }
+
+ #[test]
+ fn detect_syscall_define1() {
+ let content = r#"
+/**
+ * sys_close - close a file descriptor
+ * context-flags: KAPI_CTX_PROCESS
+ * @fd: file descriptor to close
+ * error-code: EBADF
+ */
+SYSCALL_DEFINE1(close, unsigned int, fd)
+{
+ return 0;
+}
+"#;
+ let ext = make_extractor();
+ let specs = ext.extract_from_content(content).unwrap();
+ assert_eq!(specs.len(), 1);
+ assert_eq!(specs[0].name, "sys_close");
+ }
+
+ #[test]
+ fn detect_syscall_define6() {
+ let content = r#"
+/**
+ * sys_mmap - map memory
+ * context-flags: KAPI_CTX_PROCESS
+ * error-code: ENOMEM
+ */
+SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len, unsigned long, prot,
+ unsigned long, flags, unsigned long, fd, unsigned long, offset)
+{
+ return 0;
+}
+"#;
+ let ext = make_extractor();
+ let specs = ext.extract_from_content(content).unwrap();
+ assert_eq!(specs.len(), 1);
+ assert_eq!(specs[0].name, "sys_mmap");
+ }
+
+ #[test]
+ fn detect_ioctl_pattern() {
+ let content = r#"
+/**
+ * my_ioctl - handle ioctl
+ * context-flags: KAPI_CTX_PROCESS
+ * error-code: EINVAL
+ */
+static long my_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+ return 0;
+}
+"#;
+ let ext = make_extractor();
+ let specs = ext.extract_from_content(content).unwrap();
+ assert_eq!(specs.len(), 1);
+ assert_eq!(specs[0].name, "my_ioctl");
+ assert_eq!(specs[0].api_type, "ioctl");
+ }
+
+ #[test]
+ fn find_function_after_skips_blanks() {
+ // Test that find_function_after looks past blank lines
+ let lines = vec![
+ "",
+ "",
+ "SYSCALL_DEFINE2(foo, int, bar, int, baz)",
+ "{",
+ ];
+ let ext = make_extractor();
+ let result = ext.find_function_after(&lines, 0);
+ assert!(result.is_some());
+ let (name, api_type, _sig) = result.unwrap();
+ assert_eq!(name, "sys_foo");
+ assert_eq!(api_type, "syscall");
+ }
+
+ #[test]
+ fn find_function_after_returns_none_for_no_match() {
+ // No function declaration within lookahead range
+ let lines = vec![
+ "#include <linux/fs.h>",
+ "#define FOO 1",
+ "/* comment */",
+ ];
+ let ext = make_extractor();
+ let result = ext.find_function_after(&lines, 0);
+ // The function_regex may or may not match #define, but let's check
+ // that a pure preprocessor/comment block doesn't false-positive on syscall/ioctl
+ if let Some((_, api_type, _)) = &result {
+ assert_ne!(api_type, "syscall");
+ assert_ne!(api_type, "ioctl");
+ }
+ }
+
+ #[test]
+ fn find_function_after_detects_regular_function() {
+ let lines = vec![
+ "",
+ "int do_something(struct task_struct *task)",
+ "{",
+ ];
+ let ext = make_extractor();
+ let result = ext.find_function_after(&lines, 0);
+ assert!(result.is_some());
+ let (name, api_type, _) = result.unwrap();
+ assert_eq!(name, "do_something");
+ assert_eq!(api_type, "function");
+ }
+
+ #[test]
+ fn no_kapi_annotations_produces_empty() {
+ // kerneldoc without any KAPI annotations should not produce a spec
+ let content = r#"
+/**
+ * my_func - does stuff
+ * @arg: an argument
+ */
+void my_func(int arg)
+{
+}
+"#;
+ let ext = make_extractor();
+ let specs = ext.extract_from_content(content).unwrap();
+ assert!(specs.is_empty());
+ }
+
+ #[test]
+ fn multiple_syscalls_in_one_file() {
+ let content = r#"
+/**
+ * sys_read - read from fd
+ * context-flags: KAPI_CTX_PROCESS
+ * error-code: EBADF
+ */
+SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
+{
+ return 0;
+}
+
+/**
+ * sys_write - write to fd
+ * context-flags: KAPI_CTX_PROCESS
+ * error-code: EBADF
+ */
+SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf, size_t, count)
+{
+ return 0;
+}
+"#;
+ let ext = make_extractor();
+ let specs = ext.extract_from_content(content).unwrap();
+ assert_eq!(specs.len(), 2);
+ assert_eq!(specs[0].name, "sys_read");
+ assert_eq!(specs[1].name, "sys_write");
+ }
+}
\ No newline at end of file
diff --git a/tools/kapi/src/extractor/vmlinux/binary_utils.rs b/tools/kapi/src/extractor/vmlinux/binary_utils.rs
new file mode 100644
index 0000000000000..22bdea5868fca
--- /dev/null
+++ b/tools/kapi/src/extractor/vmlinux/binary_utils.rs
@@ -0,0 +1,508 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2026 Sasha Levin <sashal@kernel.org>
+
+// Constants for all structure field sizes
+pub mod sizes {
+ pub const NAME: usize = 128;
+ pub const DESC: usize = 512;
+ pub const MAX_PARAMS: usize = 16;
+ pub const MAX_ERRORS: usize = 32;
+ pub const MAX_CONSTRAINTS: usize = 32;
+ pub const MAX_CAPABILITIES: usize = 8;
+ pub const MAX_SIGNALS: usize = 32;
+ pub const MAX_STRUCT_SPECS: usize = 8;
+ pub const MAX_SIDE_EFFECTS: usize = 32;
+ pub const MAX_STATE_TRANS: usize = 8;
+ pub const MAX_PROTOCOL_BEHAVIORS: usize = 8;
+ pub const MAX_ADDR_FAMILIES: usize = 8;
+}
+
+/// Endianness of the target ELF binary
+#[derive(Clone, Copy, PartialEq)]
+pub enum Endian {
+ Little,
+ Big,
+}
+
+// Helper for reading data at specific offsets
+pub struct DataReader<'a> {
+ pub data: &'a [u8],
+ pub pos: usize,
+ pub endian: Endian,
+ /// true for 64-bit ELF, false for 32-bit
+ pub is_64bit: bool,
+}
+
+impl<'a> DataReader<'a> {
+ pub fn new(data: &'a [u8], offset: usize, endian: Endian, is_64bit: bool) -> Self {
+ Self {
+ data,
+ pos: offset,
+ endian,
+ is_64bit,
+ }
+ }
+
+ pub fn read_bytes(&mut self, len: usize) -> Option<&'a [u8]> {
+ if self.pos + len <= self.data.len() {
+ let bytes = &self.data[self.pos..self.pos + len];
+ self.pos += len;
+ Some(bytes)
+ } else {
+ None
+ }
+ }
+
+ pub fn read_cstring(&mut self, max_len: usize) -> Option<String> {
+ let bytes = self.read_bytes(max_len)?;
+ if let Some(null_pos) = bytes.iter().position(|&b| b == 0) {
+ if null_pos > 0 {
+ if let Ok(s) = std::str::from_utf8(&bytes[..null_pos]) {
+ return Some(s.to_string());
+ }
+ }
+ }
+ None
+ }
+
+ pub fn read_u32(&mut self) -> Option<u32> {
+ let b: [u8; 4] = self.read_bytes(4)?.try_into().unwrap();
+ Some(match self.endian {
+ Endian::Little => u32::from_le_bytes(b),
+ Endian::Big => u32::from_be_bytes(b),
+ })
+ }
+
+ pub fn read_u8(&mut self) -> Option<u8> {
+ self.read_bytes(1).map(|b| b[0])
+ }
+
+ pub fn read_i32(&mut self) -> Option<i32> {
+ let b: [u8; 4] = self.read_bytes(4)?.try_into().unwrap();
+ Some(match self.endian {
+ Endian::Little => i32::from_le_bytes(b),
+ Endian::Big => i32::from_be_bytes(b),
+ })
+ }
+
+ pub fn read_u64(&mut self) -> Option<u64> {
+ let b: [u8; 8] = self.read_bytes(8)?.try_into().unwrap();
+ Some(match self.endian {
+ Endian::Little => u64::from_le_bytes(b),
+ Endian::Big => u64::from_be_bytes(b),
+ })
+ }
+
+ pub fn read_i64(&mut self) -> Option<i64> {
+ let b: [u8; 8] = self.read_bytes(8)?.try_into().unwrap();
+ Some(match self.endian {
+ Endian::Little => i64::from_le_bytes(b),
+ Endian::Big => i64::from_be_bytes(b),
+ })
+ }
+
+ /// Read a target-sized unsigned value (4 bytes for 32-bit, 8 bytes for 64-bit)
+ pub fn read_usize(&mut self) -> Option<usize> {
+ if self.is_64bit {
+ self.read_u64().map(|v| v as usize)
+ } else {
+ self.read_u32().map(|v| v as usize)
+ }
+ }
+
+ pub fn skip(&mut self, len: usize) {
+ self.pos = (self.pos + len).min(self.data.len());
+ }
+
+ // Helper methods for common patterns
+ pub fn read_bool(&mut self) -> Option<bool> {
+ self.read_u8().map(|v| v != 0)
+ }
+
+ pub fn read_optional_string(&mut self, max_len: usize) -> Option<String> {
+ self.read_cstring(max_len).filter(|s| !s.is_empty())
+ }
+
+ pub fn read_string_or_default(&mut self, max_len: usize) -> String {
+ self.read_cstring(max_len).unwrap_or_default()
+ }
+
+ // Skip and discard - advances position by reading and discarding
+ pub fn discard_cstring(&mut self, max_len: usize) {
+ let _ = self.read_cstring(max_len);
+ }
+
+}
+
+// Structure layout definitions for calculating sizes
+pub fn signal_mask_spec_layout_size() -> usize {
+ // Packed structure from struct kapi_signal_mask_spec
+ sizes::NAME + // mask_name
+ 4 * sizes::MAX_SIGNALS + // signals array
+ 4 + // signal_count
+ sizes::DESC // description
+}
+
+pub fn struct_field_layout_size() -> usize {
+ // Packed structure from struct kapi_struct_field
+ sizes::NAME + // name
+ 4 + // type (enum)
+ sizes::NAME + // type_name
+ 8 + // offset (size_t)
+ 8 + // size (size_t)
+ 4 + // flags
+ 4 + // constraint_type (enum)
+ 8 + // min_value (s64)
+ 8 + // max_value (s64)
+ 8 + // valid_mask (u64)
+ sizes::DESC + // enum_values
+ sizes::DESC // description
+}
+
+pub fn socket_state_spec_layout_size() -> usize {
+ // struct kapi_socket_state_spec
+ sizes::NAME * sizes::MAX_CONSTRAINTS + // required_states array
+ sizes::NAME * sizes::MAX_CONSTRAINTS + // forbidden_states array
+ sizes::NAME + // resulting_state
+ sizes::DESC + // condition
+ sizes::NAME + // applicable_protocols
+ 4 + // required_count
+ 4 // forbidden_count
+}
+
+pub fn protocol_behavior_spec_layout_size() -> usize {
+ // struct kapi_protocol_behavior
+ sizes::NAME + // applicable_protocols
+ sizes::DESC + // behavior
+ sizes::NAME + // protocol_flags
+ sizes::DESC // flag_description
+}
+
+pub fn buffer_spec_layout_size() -> usize {
+ // struct kapi_buffer_spec
+ sizes::DESC + // buffer_behaviors
+ 8 + // min_buffer_size (size_t)
+ 8 + // max_buffer_size (size_t)
+ 8 // optimal_buffer_size (size_t)
+}
+
+pub fn async_spec_layout_size() -> usize {
+ // struct kapi_async_spec
+ sizes::NAME + // supported_modes
+ 4 // nonblock_errno (int)
+}
+
+pub fn addr_family_spec_layout_size() -> usize {
+ // struct kapi_addr_family_spec
+ 4 + // family (int)
+ sizes::NAME + // family_name
+ 8 + // addr_struct_size (size_t)
+ 8 + // min_addr_len (size_t)
+ 8 + // max_addr_len (size_t)
+ sizes::DESC + // addr_format
+ 1 + // supports_wildcard (bool)
+ 1 + // supports_multicast (bool)
+ 1 + // supports_broadcast (bool)
+ sizes::DESC + // special_addresses
+ 4 + // port_range_min (u32)
+ 4 // port_range_max (u32)
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ // ---- DataReader little-endian tests ----
+
+ #[test]
+ fn read_u32_little_endian() {
+ let data = [0x78, 0x56, 0x34, 0x12];
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ assert_eq!(reader.read_u32(), Some(0x12345678));
+ }
+
+ #[test]
+ fn read_u32_big_endian() {
+ let data = [0x12, 0x34, 0x56, 0x78];
+ let mut reader = DataReader::new(&data, 0, Endian::Big, true);
+ assert_eq!(reader.read_u32(), Some(0x12345678));
+ }
+
+ #[test]
+ fn read_u64_little_endian() {
+ let data = 0xDEADBEEFCAFEBABEu64.to_le_bytes();
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ assert_eq!(reader.read_u64(), Some(0xDEADBEEFCAFEBABE));
+ }
+
+ #[test]
+ fn read_u64_big_endian() {
+ let data = 0xDEADBEEFCAFEBABEu64.to_be_bytes();
+ let mut reader = DataReader::new(&data, 0, Endian::Big, true);
+ assert_eq!(reader.read_u64(), Some(0xDEADBEEFCAFEBABE));
+ }
+
+ #[test]
+ fn read_i32_little_endian_negative() {
+ let val: i32 = -42;
+ let data = val.to_le_bytes();
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ assert_eq!(reader.read_i32(), Some(-42));
+ }
+
+ #[test]
+ fn read_i32_big_endian_negative() {
+ let val: i32 = -1;
+ let data = val.to_be_bytes();
+ let mut reader = DataReader::new(&data, 0, Endian::Big, true);
+ assert_eq!(reader.read_i32(), Some(-1));
+ }
+
+ #[test]
+ fn read_i64_little_endian() {
+ let val: i64 = -9999999999;
+ let data = val.to_le_bytes();
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ assert_eq!(reader.read_i64(), Some(-9999999999));
+ }
+
+ #[test]
+ fn read_i64_big_endian() {
+ let val: i64 = i64::MIN;
+ let data = val.to_be_bytes();
+ let mut reader = DataReader::new(&data, 0, Endian::Big, true);
+ assert_eq!(reader.read_i64(), Some(i64::MIN));
+ }
+
+ // ---- read_cstring tests ----
+
+ #[test]
+ fn read_cstring_nul_at_start() {
+ let data = [0u8, b'h', b'e', b'l', b'l', b'o'];
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ // NUL at position 0 means null_pos == 0, so the function returns None
+ assert_eq!(reader.read_cstring(6), None);
+ }
+
+ #[test]
+ fn read_cstring_nul_in_middle() {
+ let data = [b'h', b'i', 0, b'x', b'y'];
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ assert_eq!(reader.read_cstring(5), Some("hi".to_string()));
+ }
+
+ #[test]
+ fn read_cstring_nul_at_end() {
+ let data = [b'a', b'b', b'c', b'd', 0];
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ assert_eq!(reader.read_cstring(5), Some("abcd".to_string()));
+ }
+
+ #[test]
+ fn read_cstring_no_nul_returns_none() {
+ let data = [b'x', b'y', b'z'];
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ // No NUL terminator in the 3 bytes -> None
+ assert_eq!(reader.read_cstring(3), None);
+ }
+
+ // ---- read_usize tests ----
+
+ #[test]
+ fn read_usize_64bit() {
+ let val: u64 = 0x00000000FFFFFFFF;
+ let data = val.to_le_bytes();
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ assert_eq!(reader.read_usize(), Some(0xFFFFFFFF));
+ }
+
+ #[test]
+ fn read_usize_32bit() {
+ let val: u32 = 0xABCD1234;
+ let data = val.to_le_bytes();
+ let mut reader = DataReader::new(&data, 0, Endian::Little, false);
+ assert_eq!(reader.read_usize(), Some(0xABCD1234));
+ }
+
+ #[test]
+ fn read_usize_32bit_does_not_consume_8_bytes() {
+ // In 32-bit mode, read_usize should only consume 4 bytes
+ let mut data = [0u8; 8];
+ data[..4].copy_from_slice(&42u32.to_le_bytes());
+ data[4..8].copy_from_slice(&99u32.to_le_bytes());
+ let mut reader = DataReader::new(&data, 0, Endian::Little, false);
+ assert_eq!(reader.read_usize(), Some(42));
+ // After reading 4 bytes, pos should be at 4
+ assert_eq!(reader.pos, 4);
+ assert_eq!(reader.read_usize(), Some(99));
+ }
+
+ // ---- Bounds checking ----
+
+ #[test]
+ fn read_u32_past_end_returns_none() {
+ let data = [0x01, 0x02, 0x03]; // only 3 bytes, need 4
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ assert_eq!(reader.read_u32(), None);
+ }
+
+ #[test]
+ fn read_u64_past_end_returns_none() {
+ let data = [0u8; 7]; // only 7 bytes, need 8
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ assert_eq!(reader.read_u64(), None);
+ }
+
+ #[test]
+ fn read_bytes_past_end_returns_none() {
+ let data = [0u8; 4];
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ assert_eq!(reader.read_bytes(5), None);
+ }
+
+ #[test]
+ fn read_at_offset() {
+ let data = [0x00, 0x00, 0x78, 0x56, 0x34, 0x12];
+ let mut reader = DataReader::new(&data, 2, Endian::Little, true);
+ assert_eq!(reader.read_u32(), Some(0x12345678));
+ }
+
+ #[test]
+ fn read_bool_values() {
+ let data = [0, 1, 255];
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ assert_eq!(reader.read_bool(), Some(false));
+ assert_eq!(reader.read_bool(), Some(true));
+ assert_eq!(reader.read_bool(), Some(true)); // any non-zero is true
+ }
+
+ #[test]
+ fn skip_advances_position() {
+ let data = [0u8; 20];
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ reader.skip(10);
+ assert_eq!(reader.pos, 10);
+ reader.skip(5);
+ assert_eq!(reader.pos, 15);
+ }
+
+ #[test]
+ fn skip_clamps_to_data_len() {
+ let data = [0u8; 10];
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ reader.skip(100);
+ assert_eq!(reader.pos, 10);
+ }
+
+ #[test]
+ fn sequential_reads_advance_position() {
+ let mut data = [0u8; 12];
+ data[..4].copy_from_slice(&1u32.to_le_bytes());
+ data[4..8].copy_from_slice(&2u32.to_le_bytes());
+ data[8..12].copy_from_slice(&3u32.to_le_bytes());
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ assert_eq!(reader.read_u32(), Some(1));
+ assert_eq!(reader.read_u32(), Some(2));
+ assert_eq!(reader.read_u32(), Some(3));
+ assert_eq!(reader.pos, 12);
+ }
+
+ // ---- is_valid_api_name tests (from vmlinux/mod.rs) ----
+ // We test it via the super module since it's defined in vmlinux/mod.rs
+
+ #[test]
+ fn read_optional_string_empty_returns_none() {
+ // A string buffer that is just NUL
+ let data = [0u8; 10];
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ // read_cstring returns None when null_pos == 0
+ // read_optional_string filters empty strings, but read_cstring won't return empty
+ assert_eq!(reader.read_optional_string(10), None);
+ }
+
+ #[test]
+ fn read_string_or_default_with_empty() {
+ let data = [0u8; 10];
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ assert_eq!(reader.read_string_or_default(10), "");
+ }
+
+ #[test]
+ fn read_u8_value() {
+ let data = [0x42];
+ let mut reader = DataReader::new(&data, 0, Endian::Little, true);
+ assert_eq!(reader.read_u8(), Some(0x42));
+ }
+}
+
+/// Tests for is_valid_api_name (defined in vmlinux/mod.rs, tested here
+/// since binary_utils is its sibling module)
+#[cfg(test)]
+mod api_name_tests {
+ use super::super::is_valid_api_name;
+
+ #[test]
+ fn valid_syscall_name() {
+ assert!(is_valid_api_name("sys_open"));
+ assert!(is_valid_api_name("sys_read"));
+ assert!(is_valid_api_name("sys_write"));
+ }
+
+ #[test]
+ fn valid_ioctl_name() {
+ assert!(is_valid_api_name("vfs_ioctl"));
+ assert!(is_valid_api_name("drm_ioctl"));
+ }
+
+ #[test]
+ fn valid_dunder_name() {
+ assert!(is_valid_api_name("__do_sys_open"));
+ assert!(is_valid_api_name("__x64_sys_read"));
+ }
+
+ #[test]
+ fn empty_name_is_invalid() {
+ assert!(!is_valid_api_name(""));
+ }
+
+ #[test]
+ fn too_short_name_is_invalid() {
+ assert!(!is_valid_api_name("ab")); // len < 3
+ }
+
+ #[test]
+ fn too_long_name_is_invalid() {
+ let long_name = "a".repeat(101);
+ assert!(!is_valid_api_name(&long_name));
+ }
+
+ #[test]
+ fn name_starting_with_digit_is_invalid() {
+ assert!(!is_valid_api_name("3func_test"));
+ }
+
+ #[test]
+ fn name_with_special_chars_is_invalid() {
+ assert!(!is_valid_api_name("sys-open")); // dash not allowed
+ assert!(!is_valid_api_name("sys.open")); // dot not allowed
+ assert!(!is_valid_api_name("sys open")); // space not allowed
+ }
+
+ #[test]
+ fn name_with_underscore_is_valid() {
+ assert!(is_valid_api_name("do_some_thing"));
+ assert!(is_valid_api_name("_internal_func"));
+ }
+
+ #[test]
+ fn long_name_without_underscore_is_valid_if_gt_6() {
+ // name.len() > 6 is the fallback condition
+ assert!(is_valid_api_name("longname")); // 8 chars, no underscore but len > 6
+ }
+
+ #[test]
+ fn short_name_without_pattern_may_be_invalid() {
+ // "abc" has len 3, no underscore, no prefix match, len <= 6
+ assert!(!is_valid_api_name("abc"));
+ }
+}
diff --git a/tools/kapi/src/extractor/vmlinux/magic_finder.rs b/tools/kapi/src/extractor/vmlinux/magic_finder.rs
new file mode 100644
index 0000000000000..e3402db85c383
--- /dev/null
+++ b/tools/kapi/src/extractor/vmlinux/magic_finder.rs
@@ -0,0 +1,115 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2026 Sasha Levin <sashal@kernel.org>
+
+use super::binary_utils::Endian;
+
+// Magic markers for each section
+pub const MAGIC_PARAM: u32 = 0x4B415031; // 'KAP1'
+pub const MAGIC_RETURN: u32 = 0x4B415232; // 'KAR2'
+pub const MAGIC_ERROR: u32 = 0x4B414533; // 'KAE3'
+pub const MAGIC_LOCK: u32 = 0x4B414C34; // 'KAL4'
+pub const MAGIC_CONSTRAINT: u32 = 0x4B414335; // 'KAC5'
+pub const MAGIC_INFO: u32 = 0x4B414936; // 'KAI6'
+pub const MAGIC_SIGNAL: u32 = 0x4B415337; // 'KAS7'
+pub const MAGIC_SIGMASK: u32 = 0x4B414D38; // 'KAM8'
+pub const MAGIC_STRUCT: u32 = 0x4B415439; // 'KAT9'
+pub const MAGIC_EFFECT: u32 = 0x4B414641; // 'KAFA'
+pub const MAGIC_TRANS: u32 = 0x4B415442; // 'KATB'
+pub const MAGIC_CAP: u32 = 0x4B414343; // 'KACC'
+
+fn read_u32_endian(bytes: &[u8], endian: Endian) -> u32 {
+ let b = [bytes[0], bytes[1], bytes[2], bytes[3]];
+ match endian {
+ Endian::Little => u32::from_le_bytes(b),
+ Endian::Big => u32::from_be_bytes(b),
+ }
+}
+
+pub struct MagicOffsets {
+ pub param_offset: Option<usize>,
+ pub return_offset: Option<usize>,
+ pub error_offset: Option<usize>,
+ pub lock_offset: Option<usize>,
+ pub constraint_offset: Option<usize>,
+ pub info_offset: Option<usize>,
+ pub signal_offset: Option<usize>,
+ pub sigmask_offset: Option<usize>,
+ pub struct_offset: Option<usize>,
+ pub effect_offset: Option<usize>,
+ pub trans_offset: Option<usize>,
+ pub cap_offset: Option<usize>,
+}
+
+impl MagicOffsets {
+ /// Find magic markers in the provided data slice
+ /// data: slice of data to search (typically one spec's worth)
+ /// base_offset: absolute offset where this slice starts in the full buffer
+ pub fn find_in_data(data: &[u8], base_offset: usize, endian: Endian) -> Self {
+ let mut offsets = MagicOffsets {
+ param_offset: None,
+ return_offset: None,
+ error_offset: None,
+ lock_offset: None,
+ constraint_offset: None,
+ info_offset: None,
+ signal_offset: None,
+ sigmask_offset: None,
+ struct_offset: None,
+ effect_offset: None,
+ trans_offset: None,
+ cap_offset: None,
+ };
+
+ // Scan through data looking for magic markers
+ // Only find the first occurrence of each magic to avoid cross-spec contamination
+ let mut i = 0;
+ while i + 4 <= data.len() {
+ let bytes = &data[i..i + 4];
+ let value = read_u32_endian(bytes, endian);
+
+ match value {
+ MAGIC_PARAM if offsets.param_offset.is_none() => {
+ offsets.param_offset = Some(base_offset + i);
+ },
+ MAGIC_RETURN if offsets.return_offset.is_none() => {
+ offsets.return_offset = Some(base_offset + i);
+ },
+ MAGIC_ERROR if offsets.error_offset.is_none() => {
+ offsets.error_offset = Some(base_offset + i);
+ },
+ MAGIC_LOCK if offsets.lock_offset.is_none() => {
+ offsets.lock_offset = Some(base_offset + i);
+ },
+ MAGIC_CONSTRAINT if offsets.constraint_offset.is_none() => {
+ offsets.constraint_offset = Some(base_offset + i);
+ },
+ MAGIC_INFO if offsets.info_offset.is_none() => {
+ offsets.info_offset = Some(base_offset + i);
+ },
+ MAGIC_SIGNAL if offsets.signal_offset.is_none() => {
+ offsets.signal_offset = Some(base_offset + i);
+ },
+ MAGIC_SIGMASK if offsets.sigmask_offset.is_none() => {
+ offsets.sigmask_offset = Some(base_offset + i);
+ },
+ MAGIC_STRUCT if offsets.struct_offset.is_none() => {
+ offsets.struct_offset = Some(base_offset + i);
+ },
+ MAGIC_EFFECT if offsets.effect_offset.is_none() => {
+ offsets.effect_offset = Some(base_offset + i);
+ },
+ MAGIC_TRANS if offsets.trans_offset.is_none() => {
+ offsets.trans_offset = Some(base_offset + i);
+ },
+ MAGIC_CAP if offsets.cap_offset.is_none() => {
+ offsets.cap_offset = Some(base_offset + i);
+ },
+ _ => {}
+ }
+
+ i += 1;
+ }
+
+ offsets
+ }
+}
\ No newline at end of file
diff --git a/tools/kapi/src/extractor/vmlinux/mod.rs b/tools/kapi/src/extractor/vmlinux/mod.rs
new file mode 100644
index 0000000000000..636b825daffd5
--- /dev/null
+++ b/tools/kapi/src/extractor/vmlinux/mod.rs
@@ -0,0 +1,844 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2026 Sasha Levin <sashal@kernel.org>
+
+use super::{
+ ApiExtractor, ApiSpec, CapabilitySpec, ConstraintSpec, ErrorSpec, LockSpec, ParamSpec,
+ ReturnSpec, SideEffectSpec, SignalMaskSpec, SignalSpec, StateTransitionSpec, StructSpec,
+ StructFieldSpec,
+};
+use crate::formatter::OutputFormatter;
+use anyhow::{Context, Result};
+use goblin::elf::Elf;
+use std::fs;
+use std::io::Write;
+
+mod binary_utils;
+mod magic_finder;
+use binary_utils::{
+ DataReader, Endian, addr_family_spec_layout_size, async_spec_layout_size,
+ buffer_spec_layout_size, protocol_behavior_spec_layout_size, signal_mask_spec_layout_size,
+ sizes, socket_state_spec_layout_size, struct_field_layout_size,
+};
+
+// Helper to convert empty strings to None
+fn opt_string(s: String) -> Option<String> {
+ if s.is_empty() { None } else { Some(s) }
+}
+
+pub struct VmlinuxExtractor {
+ kapi_data: Vec<u8>,
+ specs: Vec<KapiSpec>,
+ endian: Endian,
+ is_64bit: bool,
+}
+
+#[derive(Debug)]
+struct KapiSpec {
+ name: String,
+ api_type: String,
+ offset: usize,
+}
+
+impl VmlinuxExtractor {
+ pub fn new(vmlinux_path: &str) -> Result<Self> {
+ let vmlinux_data = fs::read(vmlinux_path)
+ .with_context(|| format!("Failed to read vmlinux file: {vmlinux_path}"))?;
+
+ let elf = Elf::parse(&vmlinux_data).context("Failed to parse ELF file")?;
+
+ let endian = if elf.little_endian { Endian::Little } else { Endian::Big };
+ let is_64bit = elf.is_64;
+
+ // Find __start_kapi_specs and __stop_kapi_specs symbols first
+ let mut start_addr = None;
+ let mut stop_addr = None;
+
+ for sym in &elf.syms {
+ if let Some(name) = elf.strtab.get_at(sym.st_name) {
+ match name {
+ "__start_kapi_specs" => start_addr = Some(sym.st_value),
+ "__stop_kapi_specs" => stop_addr = Some(sym.st_value),
+ _ => {}
+ }
+ }
+ }
+
+ let start = start_addr.context("Could not find __start_kapi_specs symbol")?;
+ let stop = stop_addr.context("Could not find __stop_kapi_specs symbol")?;
+
+ if stop <= start {
+ anyhow::bail!("No kernel API specifications found in vmlinux");
+ }
+
+ // Find the section containing the kapi specs data
+ // The specs may be in .kapi_specs (standalone) or .rodata (embedded in RO_DATA)
+ let containing_section = elf
+ .section_headers
+ .iter()
+ .find(|sh| {
+ // Check if this section contains the start address
+ start >= sh.sh_addr && start < sh.sh_addr + sh.sh_size
+ })
+ .context("Could not find section containing kapi_specs data")?;
+
+ // Calculate the offset within the file
+ let section_vaddr = containing_section.sh_addr;
+ let file_offset = containing_section.sh_offset + (start - section_vaddr);
+ let data_size: usize = (stop - start)
+ .try_into()
+ .context("Data size too large for platform")?;
+
+ let file_offset_usize: usize = file_offset
+ .try_into()
+ .context("File offset too large for platform")?;
+
+ if file_offset_usize + data_size > vmlinux_data.len() {
+ anyhow::bail!("Invalid offset/size for kapi_specs data");
+ }
+
+ // Extract the raw data
+ let kapi_data = vmlinux_data[file_offset_usize..(file_offset_usize + data_size)].to_vec();
+
+ // Parse the specifications
+ let specs = parse_kapi_specs(&kapi_data, endian)?;
+
+ Ok(VmlinuxExtractor { kapi_data, specs, endian, is_64bit })
+ }
+}
+
+fn parse_kapi_specs(data: &[u8], endian: Endian) -> Result<Vec<KapiSpec>> {
+ let mut specs = Vec::new();
+ let mut offset = 0;
+ let mut last_found_offset = None;
+
+ // Expected offset from struct start to param_magic based on struct layout
+ let param_magic_offset = sizes::NAME + 4 + sizes::DESC + (sizes::DESC * 4) + 4;
+
+ // Find specs by validating API name and magic marker pairs
+ while offset + param_magic_offset + 4 <= data.len() {
+ // Read potential API name
+ let name_bytes = &data[offset..offset + sizes::NAME.min(data.len() - offset)];
+
+ // Find null terminator
+ let name_len = name_bytes.iter().position(|&b| b == 0).unwrap_or(0);
+
+ if name_len > 0 && name_len < 100 {
+ let name = String::from_utf8_lossy(&name_bytes[..name_len]).to_string();
+
+ // Validate API name format
+ if is_valid_api_name(&name) {
+ // Verify magic marker at expected position
+ let magic_offset = offset + param_magic_offset;
+ if magic_offset + 4 <= data.len() {
+ let magic_bytes = &data[magic_offset..magic_offset + 4];
+ let magic_value = match endian {
+ Endian::Little => u32::from_le_bytes([magic_bytes[0], magic_bytes[1], magic_bytes[2], magic_bytes[3]]),
+ Endian::Big => u32::from_be_bytes([magic_bytes[0], magic_bytes[1], magic_bytes[2], magic_bytes[3]]),
+ };
+
+ if magic_value == magic_finder::MAGIC_PARAM {
+ // Avoid duplicate detection of the same spec
+ if last_found_offset.is_none() || offset >= last_found_offset.unwrap() + param_magic_offset {
+ let api_type = if name.starts_with("sys_") {
+ "syscall"
+ } else if name.ends_with("_ioctl") {
+ "ioctl"
+ } else if name.contains("sysfs") {
+ "sysfs"
+ } else {
+ "function"
+ }
+ .to_string();
+
+ specs.push(KapiSpec {
+ name: name.clone(),
+ api_type,
+ offset,
+ });
+
+ last_found_offset = Some(offset);
+ }
+ }
+ }
+ }
+ }
+
+ // Scan byte by byte to find all specs
+ offset += 1;
+ }
+
+ Ok(specs)
+}
+
+
+
+
+fn is_valid_api_name(name: &str) -> bool {
+ // Validate API name format and length
+ if name.is_empty() || name.len() < 3 || name.len() > 100 {
+ return false;
+ }
+
+ // Alphanumeric and underscore characters only
+ if !name.chars().all(|c| c.is_ascii_alphanumeric() || c == '_') {
+ return false;
+ }
+
+ // Must start with letter or underscore
+ let first_char = name.chars().next().unwrap();
+ if !first_char.is_ascii_alphabetic() && first_char != '_' {
+ return false;
+ }
+
+ // Match common kernel API patterns
+ name.starts_with("sys_") ||
+ name.starts_with("__") ||
+ name.ends_with("_ioctl") ||
+ name.contains("_") ||
+ name.len() > 6
+}
+
+impl ApiExtractor for VmlinuxExtractor {
+ fn extract_all(&self) -> Result<Vec<ApiSpec>> {
+ Ok(self
+ .specs
+ .iter()
+ .map(|spec| {
+ // Parse the full spec for listing
+ parse_binary_to_api_spec(&self.kapi_data, spec.offset, self.endian, self.is_64bit)
+ .unwrap_or_else(|_| ApiSpec {
+ name: spec.name.clone(),
+ api_type: spec.api_type.clone(),
+ ..Default::default()
+ })
+ })
+ .collect())
+ }
+
+ fn extract_by_name(&self, api_name: &str) -> Result<Option<ApiSpec>> {
+ if let Some(spec) = self.specs.iter().find(|s| s.name == api_name) {
+ Ok(Some(parse_binary_to_api_spec(&self.kapi_data, spec.offset, self.endian, self.is_64bit)?))
+ } else {
+ Ok(None)
+ }
+ }
+
+ fn display_api_details(
+ &self,
+ api_name: &str,
+ formatter: &mut dyn OutputFormatter,
+ writer: &mut dyn Write,
+ ) -> Result<()> {
+ if let Some(spec) = self.specs.iter().find(|s| s.name == api_name) {
+ let api_spec = parse_binary_to_api_spec(&self.kapi_data, spec.offset, self.endian, self.is_64bit)?;
+ super::display_api_spec(&api_spec, formatter, writer)?;
+ }
+ Ok(())
+ }
+}
+
+/// Helper to read count and parse array items with optional magic offset
+fn parse_array_with_magic<T, F>(
+ reader: &mut DataReader,
+ magic_offset: Option<usize>,
+ max_items: u32,
+ parse_fn: F,
+) -> Vec<T>
+where
+ F: Fn(&mut DataReader, usize) -> Option<T>,
+{
+ // Read count - position at magic+4 if magic offset exists
+ let count = if let Some(offset) = magic_offset {
+ reader.pos = offset + 4;
+ reader.read_u32()
+ } else {
+ reader.read_u32()
+ };
+
+ let mut items = Vec::new();
+ if let Some(count) = count {
+ // Position at start of array data if magic offset exists
+ if let Some(offset) = magic_offset {
+ reader.pos = offset + 8; // +4 for magic, +4 for count
+ }
+ // Parse items up to max_items
+ for i in 0..count.min(max_items) as usize {
+ if let Some(item) = parse_fn(reader, i) {
+ items.push(item);
+ }
+ }
+ }
+ items
+}
+
+fn parse_binary_to_api_spec(data: &[u8], offset: usize, endian: Endian, is_64bit: bool) -> Result<ApiSpec> {
+ let mut reader = DataReader::new(data, offset, endian, is_64bit);
+
+ // Search for magic markers in the entire spec data
+ let search_end = (offset + 0x70000).min(data.len()); // Search full spec size
+ let spec_data = &data[offset..search_end];
+
+ // Find magic markers relative to the spec start
+ let magic_offsets = magic_finder::MagicOffsets::find_in_data(spec_data, offset, endian);
+
+ // Read fields in exact order of struct kernel_api_spec
+
+ // Read name (128 bytes)
+ let name = reader
+ .read_cstring(sizes::NAME)
+ .ok_or_else(|| anyhow::anyhow!("Failed to read API name"))?;
+
+ // Determine API type
+ let api_type = if name.starts_with("sys_") {
+ "syscall"
+ } else if name.ends_with("_ioctl") {
+ "ioctl"
+ } else if name.contains("sysfs") {
+ "sysfs"
+ } else {
+ "function"
+ }
+ .to_string();
+
+ // Read version (u32)
+ let version = reader.read_u32().map(|v| v.to_string());
+
+ // Read description (512 bytes)
+ let description = reader.read_cstring(sizes::DESC).filter(|s| !s.is_empty());
+
+ // Read long_description (2048 bytes)
+ let long_description = reader
+ .read_cstring(sizes::DESC * 4)
+ .filter(|s| !s.is_empty());
+
+ // Read context_flags (u32)
+ let context_flags = parse_context_flags(&mut reader);
+
+ // Parse params array
+ let parameters = parse_array_with_magic(
+ &mut reader,
+ magic_offsets.param_offset,
+ sizes::MAX_PARAMS as u32,
+ parse_param,
+ );
+
+ // Read return_spec - position using magic offset if available
+ if let Some(offset) = magic_offsets.return_offset {
+ reader.pos = offset + 4; // skip past the return_magic u32
+ }
+ let return_spec = parse_return_spec(&mut reader);
+
+ // Parse errors array
+ let errors = parse_array_with_magic(
+ &mut reader,
+ magic_offsets.error_offset,
+ sizes::MAX_ERRORS as u32,
+ |r, _| parse_error(r),
+ );
+
+ // Parse locks array
+ let locks = parse_array_with_magic(
+ &mut reader,
+ magic_offsets.lock_offset,
+ sizes::MAX_CONSTRAINTS as u32,
+ |r, _| parse_lock(r),
+ );
+
+ // Parse constraints array
+ let constraints = parse_array_with_magic(
+ &mut reader,
+ magic_offsets.constraint_offset,
+ sizes::MAX_CONSTRAINTS as u32,
+ |r, _| parse_constraint(r),
+ );
+
+ // Read examples and notes - position reader at info section if magic found
+ let (examples, notes) = if let Some(info_offset) = magic_offsets.info_offset {
+ reader.pos = info_offset + 4; // +4 to skip magic
+ let examples = reader.read_cstring(sizes::DESC * 2).filter(|s| !s.is_empty());
+ let notes = reader.read_cstring(sizes::DESC * 2).filter(|s| !s.is_empty());
+ (examples, notes)
+ } else {
+ let examples = reader.read_cstring(sizes::DESC * 2).filter(|s| !s.is_empty());
+ let notes = reader.read_cstring(sizes::DESC * 2).filter(|s| !s.is_empty());
+ (examples, notes)
+ };
+
+ // Skip since_version (32 bytes)
+ reader.skip(32);
+
+ // Skip deprecated (bool = 1 byte + 3 bytes padding) and replacement (128 bytes)
+ // These fields were removed from kernel but we need to skip them for binary compatibility
+ reader.skip(4); // deprecated + padding
+ reader.discard_cstring(sizes::NAME); // replacement
+
+ // Parse signals array
+ let signals = parse_array_with_magic(
+ &mut reader,
+ magic_offsets.signal_offset,
+ sizes::MAX_SIGNALS as u32,
+ |r, _| parse_signal(r),
+ );
+
+ // Read signal_mask_count (u32)
+ let signal_mask_count = reader.read_u32();
+
+ // Parse signal_masks array
+ let mut signal_masks = Vec::new();
+ if let Some(count) = signal_mask_count {
+ for i in 0..sizes::MAX_SIGNALS {
+ if i < count as usize {
+ if let Some(mask) = parse_signal_mask(&mut reader) {
+ signal_masks.push(mask);
+ }
+ } else {
+ reader.skip(signal_mask_spec_layout_size());
+ }
+ }
+ } else {
+ reader.skip(signal_mask_spec_layout_size() * sizes::MAX_SIGNALS);
+ }
+
+ // Parse struct_specs array
+ let struct_specs = parse_array_with_magic(
+ &mut reader,
+ magic_offsets.struct_offset,
+ sizes::MAX_STRUCT_SPECS as u32,
+ |r, _| parse_struct_spec(r),
+ );
+
+ // According to the C struct, the order is:
+ // side_effect_count, side_effects array, state_trans_count, state_transitions array,
+ // capability_count, capabilities array
+
+ // Parse side_effects array
+ let side_effects = parse_array_with_magic(
+ &mut reader,
+ magic_offsets.effect_offset,
+ sizes::MAX_SIDE_EFFECTS as u32,
+ |r, _| parse_side_effect(r),
+ );
+
+ // Parse state_transitions array
+ let state_transitions = parse_array_with_magic(
+ &mut reader,
+ magic_offsets.trans_offset,
+ sizes::MAX_STATE_TRANS as u32,
+ |r, _| parse_state_transition(r),
+ );
+
+ // Parse capabilities array
+ let capabilities = parse_array_with_magic(
+ &mut reader,
+ magic_offsets.cap_offset,
+ sizes::MAX_CAPABILITIES as u32,
+ |r, _| parse_capability(r),
+ );
+
+ // Skip remaining network/socket fields
+ reader.skip(
+ socket_state_spec_layout_size() +
+ protocol_behavior_spec_layout_size() * sizes::MAX_PROTOCOL_BEHAVIORS +
+ 4 + // protocol_behavior_count
+ buffer_spec_layout_size() +
+ async_spec_layout_size() +
+ addr_family_spec_layout_size() * sizes::MAX_ADDR_FAMILIES +
+ 4 + // addr_family_count
+ 6 + 2 + // 6 bool flags + padding
+ sizes::DESC * 3 // 3 semantic descriptions
+ );
+
+ Ok(ApiSpec {
+ name,
+ api_type,
+ description,
+ long_description,
+ version,
+ context_flags,
+ param_count: if parameters.is_empty() { None } else { Some(parameters.len() as u32) },
+ error_count: if errors.is_empty() { None } else { Some(errors.len() as u32) },
+ examples,
+ notes,
+ subsystem: None,
+ sysfs_path: None,
+ permissions: None,
+ socket_state: None,
+ protocol_behaviors: vec![],
+ addr_families: vec![],
+ buffer_spec: None,
+ async_spec: None,
+ net_data_transfer: None,
+ capabilities,
+ parameters,
+ return_spec,
+ errors,
+ signals,
+ signal_masks,
+ side_effects,
+ state_transitions,
+ constraints,
+ locks,
+ struct_specs,
+ })
+}
+
+// Helper parsing functions
+
+fn parse_context_flags(reader: &mut DataReader) -> Vec<String> {
+ const KAPI_CTX_PROCESS: u32 = 1 << 0;
+ const KAPI_CTX_SOFTIRQ: u32 = 1 << 1;
+ const KAPI_CTX_HARDIRQ: u32 = 1 << 2;
+ const KAPI_CTX_NMI: u32 = 1 << 3;
+ const KAPI_CTX_ATOMIC: u32 = 1 << 4;
+ const KAPI_CTX_SLEEPABLE: u32 = 1 << 5;
+ const KAPI_CTX_PREEMPT_DISABLED: u32 = 1 << 6;
+ const KAPI_CTX_IRQ_DISABLED: u32 = 1 << 7;
+
+ if let Some(flags) = reader.read_u32() {
+ let mut parts = Vec::new();
+
+ if flags & KAPI_CTX_PROCESS != 0 {
+ parts.push("KAPI_CTX_PROCESS");
+ }
+ if flags & KAPI_CTX_SOFTIRQ != 0 {
+ parts.push("KAPI_CTX_SOFTIRQ");
+ }
+ if flags & KAPI_CTX_HARDIRQ != 0 {
+ parts.push("KAPI_CTX_HARDIRQ");
+ }
+ if flags & KAPI_CTX_NMI != 0 {
+ parts.push("KAPI_CTX_NMI");
+ }
+ if flags & KAPI_CTX_ATOMIC != 0 {
+ parts.push("KAPI_CTX_ATOMIC");
+ }
+ if flags & KAPI_CTX_SLEEPABLE != 0 {
+ parts.push("KAPI_CTX_SLEEPABLE");
+ }
+ if flags & KAPI_CTX_PREEMPT_DISABLED != 0 {
+ parts.push("KAPI_CTX_PREEMPT_DISABLED");
+ }
+ if flags & KAPI_CTX_IRQ_DISABLED != 0 {
+ parts.push("KAPI_CTX_IRQ_DISABLED");
+ }
+
+ parts.into_iter().map(|s| s.to_string()).collect()
+ } else {
+ vec![]
+ }
+}
+
+fn parse_param(reader: &mut DataReader, index: usize) -> Option<ParamSpec> {
+ let name = reader.read_cstring(sizes::NAME)?;
+ let type_name = reader.read_cstring(sizes::NAME)?;
+ let param_type = reader.read_u32()?;
+ let flags = reader.read_u32()?;
+ let size = reader.read_usize()?;
+ let alignment = reader.read_usize()?;
+ let min_value = reader.read_i64()?;
+ let max_value = reader.read_i64()?;
+ let valid_mask = reader.read_u64()?;
+
+ // Skip enum_values pointer (8 bytes)
+ reader.skip(8);
+ let _enum_count = reader.read_u32()?; // Must use ? to propagate errors
+ let constraint_type = reader.read_u32()?;
+ // Skip validate function pointer (8 bytes)
+ reader.skip(8);
+
+ let description = reader.read_string_or_default(sizes::DESC);
+ let constraint = reader.read_optional_string(sizes::DESC);
+ let _size_param_idx = reader.read_i32()?; // Must use ? to propagate errors
+ let _size_multiplier = reader.read_usize()?; // Must use ? to propagate errors
+
+ Some(ParamSpec {
+ index: index as u32,
+ name,
+ type_name,
+ description,
+ flags,
+ param_type,
+ constraint_type,
+ constraint,
+ min_value: Some(min_value),
+ max_value: Some(max_value),
+ valid_mask: Some(valid_mask),
+ enum_values: vec![],
+ size: Some(size as u32),
+ alignment: Some(alignment as u32),
+ })
+}
+
+fn parse_return_spec(reader: &mut DataReader) -> Option<ReturnSpec> {
+ // Read type_name, but treat empty as valid (will be empty string)
+ let type_name = reader.read_string_or_default(sizes::NAME);
+
+ // Read return_type and check_type
+ let return_type = reader.read_u32().unwrap_or(0);
+ let check_type = reader.read_u32().unwrap_or(0);
+ let success_value = reader.read_i64().unwrap_or(0);
+ let success_min = reader.read_i64().unwrap_or(0);
+ let success_max = reader.read_i64().unwrap_or(0);
+
+ // Skip error_values pointer (8 bytes)
+ reader.skip(8);
+ let _error_count = reader.read_u32().unwrap_or(0); // Don't fail on return spec
+ // Skip is_success function pointer (8 bytes)
+ reader.skip(8);
+
+ let description = reader.read_string_or_default(sizes::DESC);
+
+ // Return a spec even if type_name is empty, as long as we have some data
+ // The type_name might be a string like "KAPI_TYPE_INT" that gets stored literally
+ if type_name.is_empty() && return_type == 0 && check_type == 0 && success_value == 0 {
+ // No return spec at all
+ return None;
+ }
+
+ Some(ReturnSpec {
+ type_name,
+ description,
+ return_type,
+ check_type,
+ success_value: Some(success_value),
+ success_min: Some(success_min),
+ success_max: Some(success_max),
+ error_values: vec![],
+ })
+}
+
+fn parse_error(reader: &mut DataReader) -> Option<ErrorSpec> {
+ let error_code = reader.read_i32()?;
+ let name = reader.read_cstring(sizes::NAME)?;
+ let condition = reader.read_string_or_default(sizes::DESC);
+ let description = reader.read_string_or_default(sizes::DESC);
+
+ Some(ErrorSpec {
+ error_code,
+ name,
+ condition,
+ description,
+ })
+}
+
+fn parse_lock(reader: &mut DataReader) -> Option<LockSpec> {
+ let lock_name = reader.read_cstring(sizes::NAME)?;
+ let lock_type = reader.read_u32()?;
+ let scope = reader.read_u32()?;
+ let description = reader.read_string_or_default(sizes::DESC);
+
+ Some(LockSpec {
+ lock_name,
+ lock_type,
+ scope,
+ description,
+ })
+}
+
+fn parse_constraint(reader: &mut DataReader) -> Option<ConstraintSpec> {
+ let name = reader.read_cstring(sizes::NAME)?;
+ let description = reader.read_string_or_default(sizes::DESC);
+ let expression = reader.read_string_or_default(sizes::DESC);
+
+ // No function pointer in packed struct
+
+ Some(ConstraintSpec {
+ name,
+ description,
+ expression: opt_string(expression),
+ })
+}
+
+fn parse_signal(reader: &mut DataReader) -> Option<SignalSpec> {
+ let signal_num = reader.read_i32()?;
+ let signal_name = reader.read_cstring(32)?; // signal_name[32]
+ let direction = reader.read_u32()?;
+ let action = reader.read_u32()?;
+ let target = reader.read_optional_string(sizes::DESC); // target[512]
+ let condition = reader.read_optional_string(sizes::DESC); // condition[512]
+ let description = reader.read_optional_string(sizes::DESC); // description[512]
+ let restartable = reader.read_bool()?;
+ let sa_flags_required = reader.read_u32()?;
+ let sa_flags_forbidden = reader.read_u32()?;
+ let error_on_signal = reader.read_i32()?;
+ let _transform_to = reader.read_i32()?; // transform_to
+ let timing_bytes = reader.read_bytes(32)?; // timing[32]
+ let timing = if let Some(end) = timing_bytes.iter().position(|&b| b == 0) {
+ String::from_utf8_lossy(&timing_bytes[..end]).parse().unwrap_or(0)
+ } else {
+ 0
+ };
+ let priority = reader.read_u8()?;
+ let interruptible = reader.read_bool()?;
+ let _queue_behavior = reader.read_bytes(128)?; // queue_behavior[128]
+ let state_required = reader.read_u32()?;
+ let state_forbidden = reader.read_u32()?;
+
+ Some(SignalSpec {
+ signal_num,
+ signal_name,
+ direction,
+ action,
+ target,
+ condition,
+ description,
+ timing,
+ priority: priority as u32,
+ restartable,
+ interruptible,
+ queue: None, // queue_behavior not exposed in SignalSpec
+ sa_flags: 0, // Not directly available
+ sa_flags_required,
+ sa_flags_forbidden,
+ state_required,
+ state_forbidden,
+ error_on_signal: Some(error_on_signal),
+ })
+}
+
+fn parse_signal_mask(reader: &mut DataReader) -> Option<SignalMaskSpec> {
+ let name = reader.read_cstring(sizes::NAME)?;
+ let description = reader.read_string_or_default(sizes::DESC);
+
+ // Skip signals array
+ for _ in 0..sizes::MAX_SIGNALS {
+ reader.read_i32();
+ }
+
+ let _signal_count = reader.read_u32()?;
+
+ Some(SignalMaskSpec {
+ name,
+ description,
+ })
+}
+
+fn parse_struct_field(reader: &mut DataReader) -> Option<StructFieldSpec> {
+ let name = reader.read_cstring(sizes::NAME)?;
+ let field_type = reader.read_u32()?;
+ let type_name = reader.read_cstring(sizes::NAME)?;
+ let offset = reader.read_usize()?;
+ let size = reader.read_usize()?;
+ let flags = reader.read_u32()?;
+ let constraint_type = reader.read_u32()?;
+ let min_value = reader.read_i64()?;
+ let max_value = reader.read_i64()?;
+ let valid_mask = reader.read_u64()?;
+ // Skip enum_values field (512 bytes)
+ let _enum_values = reader.read_cstring(sizes::DESC); // Don't fail on optional field
+ let description = reader.read_string_or_default(sizes::DESC);
+
+ Some(StructFieldSpec {
+ name,
+ field_type,
+ type_name,
+ offset,
+ size,
+ flags,
+ constraint_type,
+ min_value,
+ max_value,
+ valid_mask,
+ description,
+ })
+}
+
+fn parse_struct_spec(reader: &mut DataReader) -> Option<StructSpec> {
+ let name = reader.read_cstring(sizes::NAME)?;
+ let size = reader.read_usize()?;
+ let alignment = reader.read_usize()?;
+ let field_count = reader.read_u32()?;
+
+ // Parse fields array
+ let mut fields = Vec::new();
+ for _ in 0..field_count.min(sizes::MAX_PARAMS as u32) {
+ if let Some(field) = parse_struct_field(reader) {
+ fields.push(field);
+ } else {
+ // Skip this field if we can't parse it
+ reader.skip(struct_field_layout_size());
+ }
+ }
+
+ // Skip remaining fields if any
+ let remaining = sizes::MAX_PARAMS as u32 - field_count.min(sizes::MAX_PARAMS as u32);
+ for _ in 0..remaining {
+ reader.skip(struct_field_layout_size());
+ }
+
+ let description = reader.read_string_or_default(sizes::DESC);
+
+ Some(StructSpec {
+ name,
+ size,
+ alignment,
+ field_count,
+ fields,
+ description,
+ })
+}
+
+fn parse_side_effect(reader: &mut DataReader) -> Option<SideEffectSpec> {
+ let effect_type = reader.read_u32()?;
+ let target = reader.read_cstring(sizes::NAME)?;
+ let condition = reader.read_string_or_default(sizes::DESC);
+ let description = reader.read_string_or_default(sizes::DESC);
+ let reversible = reader.read_bool()?;
+ // No padding needed for packed struct
+
+ Some(SideEffectSpec {
+ effect_type,
+ target,
+ condition: opt_string(condition),
+ description,
+ reversible,
+ })
+}
+
+fn parse_state_transition(reader: &mut DataReader) -> Option<StateTransitionSpec> {
+ let from_state = reader.read_cstring(sizes::NAME)?;
+ let to_state = reader.read_cstring(sizes::NAME)?;
+ let condition = reader.read_string_or_default(sizes::DESC);
+ let object = reader.read_cstring(sizes::NAME)?;
+ let description = reader.read_string_or_default(sizes::DESC);
+
+ Some(StateTransitionSpec {
+ object,
+ from_state,
+ to_state,
+ condition: opt_string(condition),
+ description,
+ })
+}
+
+fn parse_capability(reader: &mut DataReader) -> Option<CapabilitySpec> {
+ let capability = reader.read_i32()?;
+ let cap_name = reader.read_cstring(sizes::NAME)?;
+ let action = reader.read_u32()?;
+ let allows = reader.read_string_or_default(sizes::DESC);
+ let without_cap = reader.read_string_or_default(sizes::DESC);
+ let check_condition = reader.read_optional_string(sizes::DESC);
+ let priority = reader.read_u32()?;
+
+ let mut alternatives = Vec::new();
+ for _ in 0..sizes::MAX_CAPABILITIES {
+ if let Some(alt) = reader.read_i32() {
+ if alt != 0 {
+ alternatives.push(alt);
+ }
+ }
+ }
+
+ let _alternative_count = reader.read_u32()?; // alternative_count
+
+ Some(CapabilitySpec {
+ capability,
+ name: cap_name,
+ action: action.to_string(),
+ allows,
+ without_cap,
+ check_condition,
+ priority: Some(priority as u8),
+ alternatives,
+ })
+}
\ No newline at end of file
diff --git a/tools/kapi/src/formatter/json.rs b/tools/kapi/src/formatter/json.rs
new file mode 100644
index 0000000000000..0b0ad047d690c
--- /dev/null
+++ b/tools/kapi/src/formatter/json.rs
@@ -0,0 +1,720 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2026 Sasha Levin <sashal@kernel.org>
+
+use super::OutputFormatter;
+use crate::extractor::{
+ AddrFamilySpec, AsyncSpec, BufferSpec, CapabilitySpec, ConstraintSpec, ErrorSpec, LockSpec,
+ ParamSpec, ProtocolBehaviorSpec, ReturnSpec, SideEffectSpec, SignalMaskSpec, SignalSpec,
+ SocketStateSpec, StateTransitionSpec, StructSpec,
+};
+use serde::Serialize;
+use std::io::Write;
+
+pub struct JsonFormatter {
+ data: JsonData,
+}
+
+#[derive(Serialize)]
+struct JsonData {
+ #[serde(skip_serializing_if = "Option::is_none")]
+ apis: Option<Vec<JsonApi>>,
+ #[serde(skip_serializing_if = "Option::is_none")]
+ api_details: Option<JsonApiDetails>,
+}
+
+#[derive(Serialize)]
+struct JsonApi {
+ name: String,
+ api_type: String,
+}
+
+#[derive(Serialize)]
+struct JsonApiDetails {
+ name: String,
+ #[serde(skip_serializing_if = "Option::is_none")]
+ description: Option<String>,
+ #[serde(skip_serializing_if = "Option::is_none")]
+ long_description: Option<String>,
+ #[serde(skip_serializing_if = "Vec::is_empty")]
+ context_flags: Vec<String>,
+ #[serde(skip_serializing_if = "Option::is_none")]
+ examples: Option<String>,
+ #[serde(skip_serializing_if = "Option::is_none")]
+ notes: Option<String>,
+ // Sysfs-specific fields
+ #[serde(skip_serializing_if = "Option::is_none")]
+ subsystem: Option<String>,
+ #[serde(skip_serializing_if = "Option::is_none")]
+ sysfs_path: Option<String>,
+ #[serde(skip_serializing_if = "Option::is_none")]
+ permissions: Option<String>,
+ // Networking-specific fields
+ #[serde(skip_serializing_if = "Option::is_none")]
+ socket_state: Option<SocketStateSpec>,
+ #[serde(skip_serializing_if = "Vec::is_empty")]
+ protocol_behaviors: Vec<ProtocolBehaviorSpec>,
+ #[serde(skip_serializing_if = "Vec::is_empty")]
+ addr_families: Vec<AddrFamilySpec>,
+ #[serde(skip_serializing_if = "Option::is_none")]
+ buffer_spec: Option<BufferSpec>,
+ #[serde(skip_serializing_if = "Option::is_none")]
+ async_spec: Option<AsyncSpec>,
+ #[serde(skip_serializing_if = "Option::is_none")]
+ net_data_transfer: Option<String>,
+ #[serde(skip_serializing_if = "Vec::is_empty")]
+ capabilities: Vec<CapabilitySpec>,
+ #[serde(skip_serializing_if = "Vec::is_empty")]
+ state_transitions: Vec<StateTransitionSpec>,
+ #[serde(skip_serializing_if = "Vec::is_empty")]
+ side_effects: Vec<SideEffectSpec>,
+ #[serde(skip_serializing_if = "Vec::is_empty")]
+ parameters: Vec<ParamSpec>,
+ #[serde(skip_serializing_if = "Option::is_none")]
+ return_spec: Option<ReturnSpec>,
+ #[serde(skip_serializing_if = "Vec::is_empty")]
+ errors: Vec<ErrorSpec>,
+ #[serde(skip_serializing_if = "Vec::is_empty")]
+ locks: Vec<LockSpec>,
+ #[serde(skip_serializing_if = "Vec::is_empty")]
+ struct_specs: Vec<StructSpec>,
+ #[serde(skip_serializing_if = "Vec::is_empty")]
+ signals: Vec<SignalSpec>,
+ #[serde(skip_serializing_if = "Vec::is_empty")]
+ signal_masks: Vec<SignalMaskSpec>,
+ #[serde(skip_serializing_if = "Vec::is_empty")]
+ constraints: Vec<ConstraintSpec>,
+}
+
+impl JsonFormatter {
+ pub fn new() -> Self {
+ JsonFormatter {
+ data: JsonData {
+ apis: None,
+ api_details: None,
+ },
+ }
+ }
+}
+
+impl OutputFormatter for JsonFormatter {
+ fn begin_document(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn end_document(&mut self, w: &mut dyn Write) -> std::io::Result<()> {
+ let json = serde_json::to_string_pretty(&self.data)?;
+ writeln!(w, "{json}")?;
+ Ok(())
+ }
+
+ fn begin_api_list(&mut self, _w: &mut dyn Write, _title: &str) -> std::io::Result<()> {
+ if self.data.apis.is_none() {
+ self.data.apis = Some(Vec::new());
+ }
+ Ok(())
+ }
+
+ fn api_item(&mut self, _w: &mut dyn Write, name: &str, api_type: &str) -> std::io::Result<()> {
+ if let Some(apis) = &mut self.data.apis {
+ apis.push(JsonApi {
+ name: name.to_string(),
+ api_type: api_type.to_string(),
+ });
+ }
+ Ok(())
+ }
+
+ fn end_api_list(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn total_specs(&mut self, _w: &mut dyn Write, _count: usize) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_api_details(&mut self, _w: &mut dyn Write, name: &str) -> std::io::Result<()> {
+ self.data.api_details = Some(JsonApiDetails {
+ name: name.to_string(),
+ description: None,
+ long_description: None,
+ context_flags: Vec::new(),
+ examples: None,
+ notes: None,
+ subsystem: None,
+ sysfs_path: None,
+ permissions: None,
+ socket_state: None,
+ protocol_behaviors: Vec::new(),
+ addr_families: Vec::new(),
+ buffer_spec: None,
+ async_spec: None,
+ net_data_transfer: None,
+ capabilities: Vec::new(),
+ state_transitions: Vec::new(),
+ side_effects: Vec::new(),
+ parameters: Vec::new(),
+ return_spec: None,
+ errors: Vec::new(),
+ locks: Vec::new(),
+ struct_specs: Vec::new(),
+ signals: Vec::new(),
+ signal_masks: Vec::new(),
+ constraints: Vec::new(),
+ });
+ Ok(())
+ }
+
+ fn end_api_details(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn description(&mut self, _w: &mut dyn Write, desc: &str) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.description = Some(desc.to_string());
+ }
+ Ok(())
+ }
+
+ fn long_description(&mut self, _w: &mut dyn Write, desc: &str) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.long_description = Some(desc.to_string());
+ }
+ Ok(())
+ }
+
+ fn begin_context_flags(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn context_flag(&mut self, _w: &mut dyn Write, flag: &str) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.context_flags.push(flag.to_string());
+ }
+ Ok(())
+ }
+
+ fn end_context_flags(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_parameters(&mut self, _w: &mut dyn Write, _count: u32) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn end_parameters(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_errors(&mut self, _w: &mut dyn Write, _count: u32) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn end_errors(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn examples(&mut self, _w: &mut dyn Write, examples: &str) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.examples = Some(examples.to_string());
+ }
+ Ok(())
+ }
+
+ fn notes(&mut self, _w: &mut dyn Write, notes: &str) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.notes = Some(notes.to_string());
+ }
+ Ok(())
+ }
+
+ fn sysfs_subsystem(&mut self, _w: &mut dyn Write, subsystem: &str) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.subsystem = Some(subsystem.to_string());
+ }
+ Ok(())
+ }
+
+ fn sysfs_path(&mut self, _w: &mut dyn Write, path: &str) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.sysfs_path = Some(path.to_string());
+ }
+ Ok(())
+ }
+
+ fn sysfs_permissions(&mut self, _w: &mut dyn Write, perms: &str) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.permissions = Some(perms.to_string());
+ }
+ Ok(())
+ }
+
+ // Networking-specific methods
+ fn socket_state(&mut self, _w: &mut dyn Write, state: &SocketStateSpec) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.socket_state = Some(state.clone());
+ }
+ Ok(())
+ }
+
+ fn begin_protocol_behaviors(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn protocol_behavior(
+ &mut self,
+ _w: &mut dyn Write,
+ behavior: &ProtocolBehaviorSpec,
+ ) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.protocol_behaviors.push(behavior.clone());
+ }
+ Ok(())
+ }
+
+ fn end_protocol_behaviors(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_addr_families(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn addr_family(&mut self, _w: &mut dyn Write, family: &AddrFamilySpec) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.addr_families.push(family.clone());
+ }
+ Ok(())
+ }
+
+ fn end_addr_families(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn buffer_spec(&mut self, _w: &mut dyn Write, spec: &BufferSpec) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.buffer_spec = Some(spec.clone());
+ }
+ Ok(())
+ }
+
+ fn async_spec(&mut self, _w: &mut dyn Write, spec: &AsyncSpec) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.async_spec = Some(spec.clone());
+ }
+ Ok(())
+ }
+
+ fn net_data_transfer(&mut self, _w: &mut dyn Write, desc: &str) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.net_data_transfer = Some(desc.to_string());
+ }
+ Ok(())
+ }
+
+ fn begin_capabilities(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn capability(&mut self, _w: &mut dyn Write, cap: &CapabilitySpec) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.capabilities.push(cap.clone());
+ }
+ Ok(())
+ }
+
+ fn end_capabilities(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn parameter(&mut self, _w: &mut dyn Write, param: &ParamSpec) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.parameters.push(param.clone());
+ }
+ Ok(())
+ }
+
+ fn return_spec(&mut self, _w: &mut dyn Write, ret: &ReturnSpec) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.return_spec = Some(ret.clone());
+ }
+ Ok(())
+ }
+
+ fn error(&mut self, _w: &mut dyn Write, error: &ErrorSpec) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.errors.push(error.clone());
+ }
+ Ok(())
+ }
+
+ fn begin_signals(&mut self, _w: &mut dyn Write, _count: u32) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn signal(&mut self, _w: &mut dyn Write, signal: &SignalSpec) -> std::io::Result<()> {
+ if let Some(api_details) = &mut self.data.api_details {
+ api_details.signals.push(signal.clone());
+ }
+ Ok(())
+ }
+
+ fn end_signals(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_signal_masks(&mut self, _w: &mut dyn Write, _count: u32) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn signal_mask(&mut self, _w: &mut dyn Write, mask: &SignalMaskSpec) -> std::io::Result<()> {
+ if let Some(api_details) = &mut self.data.api_details {
+ api_details.signal_masks.push(mask.clone());
+ }
+ Ok(())
+ }
+
+ fn end_signal_masks(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_side_effects(&mut self, _w: &mut dyn Write, _count: u32) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn side_effect(&mut self, _w: &mut dyn Write, effect: &SideEffectSpec) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.side_effects.push(effect.clone());
+ }
+ Ok(())
+ }
+
+ fn end_side_effects(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_state_transitions(&mut self, _w: &mut dyn Write, _count: u32) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn state_transition(
+ &mut self,
+ _w: &mut dyn Write,
+ trans: &StateTransitionSpec,
+ ) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.state_transitions.push(trans.clone());
+ }
+ Ok(())
+ }
+
+ fn end_state_transitions(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_constraints(&mut self, _w: &mut dyn Write, _count: u32) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn constraint(
+ &mut self,
+ _w: &mut dyn Write,
+ constraint: &ConstraintSpec,
+ ) -> std::io::Result<()> {
+ if let Some(api_details) = &mut self.data.api_details {
+ api_details.constraints.push(constraint.clone());
+ }
+ Ok(())
+ }
+
+ fn end_constraints(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_locks(&mut self, _w: &mut dyn Write, _count: u32) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn lock(&mut self, _w: &mut dyn Write, lock: &LockSpec) -> std::io::Result<()> {
+ if let Some(details) = &mut self.data.api_details {
+ details.locks.push(lock.clone());
+ }
+ Ok(())
+ }
+
+ fn end_locks(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_struct_specs(&mut self, _w: &mut dyn Write, _count: u32) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn struct_spec(&mut self, _w: &mut dyn Write, spec: &StructSpec) -> std::io::Result<()> {
+ if let Some(ref mut details) = self.data.api_details {
+ details.struct_specs.push(spec.clone());
+ }
+ Ok(())
+ }
+
+ fn end_struct_specs(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+ use crate::extractor::{ErrorSpec, ParamSpec, ReturnSpec};
+
+ fn render_json(f: &mut JsonFormatter) -> String {
+ let mut buf = Vec::new();
+ f.end_document(&mut buf).unwrap();
+ String::from_utf8(buf).unwrap()
+ }
+
+ #[test]
+ fn json_output_is_valid() {
+ let mut f = JsonFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_test").unwrap();
+ f.description(&mut sink, "A test syscall").unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let json = render_json(&mut f);
+
+ // Verify it parses as valid JSON
+ let parsed: serde_json::Value = serde_json::from_str(&json).unwrap();
+ assert_eq!(
+ parsed["api_details"]["name"].as_str(),
+ Some("sys_test")
+ );
+ assert_eq!(
+ parsed["api_details"]["description"].as_str(),
+ Some("A test syscall")
+ );
+ }
+
+ #[test]
+ fn json_api_list() {
+ let mut f = JsonFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_list(&mut sink, "Syscalls").unwrap();
+ f.api_item(&mut sink, "sys_open", "syscall").unwrap();
+ f.api_item(&mut sink, "sys_read", "syscall").unwrap();
+ f.end_api_list(&mut sink).unwrap();
+
+ let json = render_json(&mut f);
+ let parsed: serde_json::Value = serde_json::from_str(&json).unwrap();
+
+ let apis = parsed["apis"].as_array().unwrap();
+ assert_eq!(apis.len(), 2);
+ assert_eq!(apis[0]["name"].as_str(), Some("sys_open"));
+ assert_eq!(apis[0]["api_type"].as_str(), Some("syscall"));
+ assert_eq!(apis[1]["name"].as_str(), Some("sys_read"));
+ }
+
+ #[test]
+ fn json_special_characters_in_description() {
+ let mut f = JsonFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_test").unwrap();
+ f.description(&mut sink, "Contains \"quotes\" and \\backslashes\\").unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let json = render_json(&mut f);
+
+ // Must be valid JSON despite special characters
+ let parsed: serde_json::Value = serde_json::from_str(&json).unwrap();
+ assert_eq!(
+ parsed["api_details"]["description"].as_str(),
+ Some("Contains \"quotes\" and \\backslashes\\")
+ );
+ }
+
+ #[test]
+ fn json_special_characters_in_name() {
+ let mut f = JsonFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_list(&mut sink, "APIs").unwrap();
+ // Names with underscores (common in kernel) and unusual strings
+ f.api_item(&mut sink, "sys_new\tline", "syscall").unwrap();
+ f.end_api_list(&mut sink).unwrap();
+
+ let json = render_json(&mut f);
+
+ // Must parse correctly; serde_json handles escaping for us
+ let parsed: serde_json::Value = serde_json::from_str(&json).unwrap();
+ assert_eq!(
+ parsed["apis"][0]["name"].as_str(),
+ Some("sys_new\tline")
+ );
+ }
+
+ #[test]
+ fn json_parameters_serialized() {
+ let mut f = JsonFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_write").unwrap();
+ f.begin_parameters(&mut sink, 2).unwrap();
+ f.parameter(
+ &mut sink,
+ &ParamSpec {
+ index: 0,
+ name: "fd".to_string(),
+ type_name: "unsigned int".to_string(),
+ description: "file descriptor".to_string(),
+ flags: 1,
+ param_type: 2,
+ constraint_type: 0,
+ constraint: None,
+ min_value: Some(0),
+ max_value: Some(1024),
+ valid_mask: None,
+ enum_values: vec![],
+ size: None,
+ alignment: None,
+ },
+ )
+ .unwrap();
+ f.end_parameters(&mut sink).unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let json = render_json(&mut f);
+ let parsed: serde_json::Value = serde_json::from_str(&json).unwrap();
+
+ let params = parsed["api_details"]["parameters"].as_array().unwrap();
+ assert_eq!(params.len(), 1);
+ assert_eq!(params[0]["name"].as_str(), Some("fd"));
+ assert_eq!(params[0]["param_type"].as_u64(), Some(2));
+ }
+
+ #[test]
+ fn json_errors_serialized() {
+ let mut f = JsonFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_read").unwrap();
+ f.begin_errors(&mut sink, 1).unwrap();
+ f.error(
+ &mut sink,
+ &ErrorSpec {
+ error_code: -9,
+ name: "EBADF".to_string(),
+ condition: "fd is not valid".to_string(),
+ description: "Bad file descriptor".to_string(),
+ },
+ )
+ .unwrap();
+ f.end_errors(&mut sink).unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let json = render_json(&mut f);
+ let parsed: serde_json::Value = serde_json::from_str(&json).unwrap();
+
+ let errors = parsed["api_details"]["errors"].as_array().unwrap();
+ assert_eq!(errors.len(), 1);
+ assert_eq!(errors[0]["name"].as_str(), Some("EBADF"));
+ assert_eq!(errors[0]["error_code"].as_i64(), Some(-9));
+ }
+
+ #[test]
+ fn json_empty_details_omits_empty_fields() {
+ let mut f = JsonFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_empty").unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let json = render_json(&mut f);
+ let parsed: serde_json::Value = serde_json::from_str(&json).unwrap();
+
+ // description should not be present (skip_serializing_if = Option::is_none)
+ assert!(parsed["api_details"]["description"].is_null());
+ // parameters empty array should not be present (skip_serializing_if = Vec::is_empty)
+ assert!(parsed["api_details"]["parameters"].is_null());
+ // errors empty array should not be present
+ assert!(parsed["api_details"]["errors"].is_null());
+ }
+
+ #[test]
+ fn json_braces_balance() {
+ let mut f = JsonFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_balanced").unwrap();
+ f.description(&mut sink, "Test braces balance").unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let json = render_json(&mut f);
+
+ let open_braces = json.chars().filter(|&c| c == '{').count();
+ let close_braces = json.chars().filter(|&c| c == '}').count();
+ assert_eq!(open_braces, close_braces, "Braces are unbalanced");
+
+ let open_brackets = json.chars().filter(|&c| c == '[').count();
+ let close_brackets = json.chars().filter(|&c| c == ']').count();
+ assert_eq!(open_brackets, close_brackets, "Brackets are unbalanced");
+ }
+
+ #[test]
+ fn json_return_spec_serialized() {
+ let mut f = JsonFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_open").unwrap();
+ f.return_spec(
+ &mut sink,
+ &ReturnSpec {
+ type_name: "int".to_string(),
+ description: "file descriptor on success".to_string(),
+ return_type: 1,
+ check_type: 3,
+ success_value: Some(0),
+ success_min: None,
+ success_max: None,
+ error_values: vec![-1],
+ },
+ )
+ .unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let json = render_json(&mut f);
+ let parsed: serde_json::Value = serde_json::from_str(&json).unwrap();
+
+ let ret = &parsed["api_details"]["return_spec"];
+ assert_eq!(ret["type_name"].as_str(), Some("int"));
+ assert_eq!(ret["check_type"].as_u64(), Some(3));
+ }
+
+ #[test]
+ fn json_unicode_in_description() {
+ let mut f = JsonFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_uni").unwrap();
+ f.description(&mut sink, "Supports unicode: \u{00e9}\u{00e8}\u{00ea}").unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let json = render_json(&mut f);
+ let parsed: serde_json::Value = serde_json::from_str(&json).unwrap();
+ assert!(parsed["api_details"]["description"]
+ .as_str()
+ .unwrap()
+ .contains('\u{00e9}'));
+ }
+}
diff --git a/tools/kapi/src/formatter/mod.rs b/tools/kapi/src/formatter/mod.rs
new file mode 100644
index 0000000000000..b0f469e7b6d78
--- /dev/null
+++ b/tools/kapi/src/formatter/mod.rs
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2026 Sasha Levin <sashal@kernel.org>
+
+use crate::extractor::{
+ AddrFamilySpec, AsyncSpec, BufferSpec, CapabilitySpec, ConstraintSpec, ErrorSpec, LockSpec,
+ ParamSpec, ProtocolBehaviorSpec, ReturnSpec, SideEffectSpec, SignalMaskSpec, SignalSpec,
+ SocketStateSpec, StateTransitionSpec, StructSpec,
+};
+use std::io::Write;
+
+mod json;
+mod plain;
+mod rst;
+
+pub use json::JsonFormatter;
+pub use plain::PlainFormatter;
+pub use rst::RstFormatter;
+
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum OutputFormat {
+ Plain,
+ Json,
+ Rst,
+}
+
+impl std::str::FromStr for OutputFormat {
+ type Err = String;
+
+ fn from_str(s: &str) -> Result<Self, Self::Err> {
+ match s.to_lowercase().as_str() {
+ "plain" => Ok(OutputFormat::Plain),
+ "json" => Ok(OutputFormat::Json),
+ "rst" => Ok(OutputFormat::Rst),
+ _ => Err(format!("Unknown output format: {}", s)),
+ }
+ }
+}
+
+pub trait OutputFormatter {
+ fn begin_document(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+ fn end_document(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+
+ fn begin_api_list(&mut self, w: &mut dyn Write, title: &str) -> std::io::Result<()>;
+ fn api_item(&mut self, w: &mut dyn Write, name: &str, api_type: &str) -> std::io::Result<()>;
+ fn end_api_list(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+
+ fn total_specs(&mut self, w: &mut dyn Write, count: usize) -> std::io::Result<()>;
+
+ fn begin_api_details(&mut self, w: &mut dyn Write, name: &str) -> std::io::Result<()>;
+ fn end_api_details(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+ fn description(&mut self, w: &mut dyn Write, desc: &str) -> std::io::Result<()>;
+ fn long_description(&mut self, w: &mut dyn Write, desc: &str) -> std::io::Result<()>;
+
+ fn begin_context_flags(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+ fn context_flag(&mut self, w: &mut dyn Write, flag: &str) -> std::io::Result<()>;
+ fn end_context_flags(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+
+ fn begin_parameters(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()>;
+ fn parameter(&mut self, w: &mut dyn Write, param: &ParamSpec) -> std::io::Result<()>;
+ fn end_parameters(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+
+ fn return_spec(&mut self, w: &mut dyn Write, ret: &ReturnSpec) -> std::io::Result<()>;
+
+ fn begin_errors(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()>;
+ fn error(&mut self, w: &mut dyn Write, error: &ErrorSpec) -> std::io::Result<()>;
+ fn end_errors(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+
+ fn examples(&mut self, w: &mut dyn Write, examples: &str) -> std::io::Result<()>;
+ fn notes(&mut self, w: &mut dyn Write, notes: &str) -> std::io::Result<()>;
+
+ // Sysfs-specific methods
+ fn sysfs_subsystem(&mut self, w: &mut dyn Write, subsystem: &str) -> std::io::Result<()>;
+ fn sysfs_path(&mut self, w: &mut dyn Write, path: &str) -> std::io::Result<()>;
+ fn sysfs_permissions(&mut self, w: &mut dyn Write, perms: &str) -> std::io::Result<()>;
+
+ // Networking-specific methods
+ fn socket_state(&mut self, w: &mut dyn Write, state: &SocketStateSpec) -> std::io::Result<()>;
+
+ fn begin_protocol_behaviors(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+ fn protocol_behavior(
+ &mut self,
+ w: &mut dyn Write,
+ behavior: &ProtocolBehaviorSpec,
+ ) -> std::io::Result<()>;
+ fn end_protocol_behaviors(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+
+ fn begin_addr_families(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+ fn addr_family(&mut self, w: &mut dyn Write, family: &AddrFamilySpec) -> std::io::Result<()>;
+ fn end_addr_families(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+
+ fn buffer_spec(&mut self, w: &mut dyn Write, spec: &BufferSpec) -> std::io::Result<()>;
+ fn async_spec(&mut self, w: &mut dyn Write, spec: &AsyncSpec) -> std::io::Result<()>;
+ fn net_data_transfer(&mut self, w: &mut dyn Write, desc: &str) -> std::io::Result<()>;
+
+ fn begin_capabilities(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+ fn capability(&mut self, w: &mut dyn Write, cap: &CapabilitySpec) -> std::io::Result<()>;
+ fn end_capabilities(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+
+ // Signal-related methods
+ fn begin_signals(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()>;
+ fn signal(&mut self, w: &mut dyn Write, signal: &SignalSpec) -> std::io::Result<()>;
+ fn end_signals(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+
+ fn begin_signal_masks(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()>;
+ fn signal_mask(&mut self, w: &mut dyn Write, mask: &SignalMaskSpec) -> std::io::Result<()>;
+ fn end_signal_masks(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+
+ // Side effects and state transitions
+ fn begin_side_effects(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()>;
+ fn side_effect(&mut self, w: &mut dyn Write, effect: &SideEffectSpec) -> std::io::Result<()>;
+ fn end_side_effects(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+
+ fn begin_state_transitions(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()>;
+ fn state_transition(
+ &mut self,
+ w: &mut dyn Write,
+ trans: &StateTransitionSpec,
+ ) -> std::io::Result<()>;
+ fn end_state_transitions(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+
+ // Constraints and locks
+ fn begin_constraints(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()>;
+ fn constraint(&mut self, w: &mut dyn Write, constraint: &ConstraintSpec)
+ -> std::io::Result<()>;
+ fn end_constraints(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+
+ fn begin_locks(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()>;
+ fn lock(&mut self, w: &mut dyn Write, lock: &LockSpec) -> std::io::Result<()>;
+ fn end_locks(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+
+ fn begin_struct_specs(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()>;
+ fn struct_spec(&mut self, w: &mut dyn Write, spec: &StructSpec) -> std::io::Result<()>;
+ fn end_struct_specs(&mut self, w: &mut dyn Write) -> std::io::Result<()>;
+}
+
+pub fn create_formatter(format: OutputFormat) -> Box<dyn OutputFormatter> {
+ match format {
+ OutputFormat::Plain => Box::new(PlainFormatter::new()),
+ OutputFormat::Json => Box::new(JsonFormatter::new()),
+ OutputFormat::Rst => Box::new(RstFormatter::new()),
+ }
+}
diff --git a/tools/kapi/src/formatter/plain.rs b/tools/kapi/src/formatter/plain.rs
new file mode 100644
index 0000000000000..ee955d8cb9bad
--- /dev/null
+++ b/tools/kapi/src/formatter/plain.rs
@@ -0,0 +1,707 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2026 Sasha Levin <sashal@kernel.org>
+
+use super::OutputFormatter;
+use crate::extractor::{
+ AddrFamilySpec, AsyncSpec, BufferSpec, CapabilitySpec, ConstraintSpec, ErrorSpec, LockSpec,
+ ParamSpec, ProtocolBehaviorSpec, ReturnSpec, SideEffectSpec, SignalMaskSpec, SignalSpec,
+ SocketStateSpec, StateTransitionSpec,
+};
+use std::io::Write;
+
+pub struct PlainFormatter;
+
+impl PlainFormatter {
+ pub fn new() -> Self {
+ PlainFormatter
+ }
+}
+
+impl OutputFormatter for PlainFormatter {
+ fn begin_document(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn end_document(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_api_list(&mut self, w: &mut dyn Write, title: &str) -> std::io::Result<()> {
+ writeln!(w, "\n{title}:")?;
+ writeln!(w, "{}", "-".repeat(title.len() + 1))
+ }
+
+ fn api_item(&mut self, w: &mut dyn Write, name: &str, _api_type: &str) -> std::io::Result<()> {
+ writeln!(w, " {name}")
+ }
+
+ fn end_api_list(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn total_specs(&mut self, w: &mut dyn Write, count: usize) -> std::io::Result<()> {
+ writeln!(w, "\nTotal specifications found: {count}")
+ }
+
+ fn begin_api_details(&mut self, w: &mut dyn Write, name: &str) -> std::io::Result<()> {
+ writeln!(w, "\nDetailed information for {name}:")?;
+ writeln!(w, "{}=", "=".repeat(25 + name.len()))
+ }
+
+ fn end_api_details(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn description(&mut self, w: &mut dyn Write, desc: &str) -> std::io::Result<()> {
+ writeln!(w, "Description: {desc}")
+ }
+
+ fn long_description(&mut self, w: &mut dyn Write, desc: &str) -> std::io::Result<()> {
+ writeln!(w, "\nDetailed Description:")?;
+ writeln!(w, "{desc}")
+ }
+
+ fn begin_context_flags(&mut self, w: &mut dyn Write) -> std::io::Result<()> {
+ writeln!(w, "\nExecution Context:")
+ }
+
+ fn context_flag(&mut self, w: &mut dyn Write, flag: &str) -> std::io::Result<()> {
+ writeln!(w, " - {flag}")
+ }
+
+ fn end_context_flags(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_parameters(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+ writeln!(w, "\nParameters ({count}):")
+ }
+
+ fn parameter(&mut self, w: &mut dyn Write, param: &ParamSpec) -> std::io::Result<()> {
+ writeln!(
+ w,
+ " [{}] {} ({})",
+ param.index, param.name, param.type_name
+ )?;
+ if !param.description.is_empty() {
+ writeln!(w, " {}", param.description)?;
+ }
+
+ // Display flags
+ let mut flags = Vec::new();
+ if param.flags & 0x01 != 0 {
+ flags.push("IN");
+ }
+ if param.flags & 0x02 != 0 {
+ flags.push("OUT");
+ }
+ if param.flags & 0x04 != 0 {
+ flags.push("INOUT");
+ }
+ if param.flags & 0x08 != 0 {
+ flags.push("USER");
+ }
+ if param.flags & 0x10 != 0 {
+ flags.push("OPTIONAL");
+ }
+ if !flags.is_empty() {
+ writeln!(w, " Flags: {}", flags.join(" | "))?;
+ }
+
+ // Display constraints
+ if let Some(constraint) = &param.constraint {
+ writeln!(w, " Constraint: {constraint}")?;
+ }
+ if let (Some(min), Some(max)) = (param.min_value, param.max_value) {
+ writeln!(w, " Range: {min} to {max}")?;
+ }
+ if let Some(mask) = param.valid_mask {
+ writeln!(w, " Valid mask: 0x{mask:x}")?;
+ }
+ Ok(())
+ }
+
+ fn end_parameters(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn return_spec(&mut self, w: &mut dyn Write, ret: &ReturnSpec) -> std::io::Result<()> {
+ writeln!(w, "\nReturn Value:")?;
+ writeln!(w, " Type: {}", ret.type_name)?;
+ writeln!(w, " {}", ret.description)?;
+ if let Some(val) = ret.success_value {
+ writeln!(w, " Success value: {val}")?;
+ }
+ if let (Some(min), Some(max)) = (ret.success_min, ret.success_max) {
+ writeln!(w, " Success range: {min} to {max}")?;
+ }
+ Ok(())
+ }
+
+ fn begin_errors(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+ writeln!(w, "\nPossible Errors ({count}):")
+ }
+
+ fn error(&mut self, w: &mut dyn Write, error: &ErrorSpec) -> std::io::Result<()> {
+ writeln!(w, " {} ({})", error.name, error.error_code)?;
+ if !error.condition.is_empty() {
+ writeln!(w, " Condition: {}", error.condition)?;
+ }
+ if !error.description.is_empty() {
+ writeln!(w, " {}", error.description)?;
+ }
+ Ok(())
+ }
+
+ fn end_errors(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn examples(&mut self, w: &mut dyn Write, examples: &str) -> std::io::Result<()> {
+ writeln!(w, "\nExamples:")?;
+ writeln!(w, "{examples}")
+ }
+
+ fn notes(&mut self, w: &mut dyn Write, notes: &str) -> std::io::Result<()> {
+ writeln!(w, "\nNotes:")?;
+ writeln!(w, "{notes}")
+ }
+
+ fn sysfs_subsystem(&mut self, w: &mut dyn Write, subsystem: &str) -> std::io::Result<()> {
+ writeln!(w, "Subsystem: {subsystem}")
+ }
+
+ fn sysfs_path(&mut self, w: &mut dyn Write, path: &str) -> std::io::Result<()> {
+ writeln!(w, "Sysfs Path: {path}")
+ }
+
+ fn sysfs_permissions(&mut self, w: &mut dyn Write, perms: &str) -> std::io::Result<()> {
+ writeln!(w, "Permissions: {perms}")
+ }
+
+ // Networking-specific methods
+ fn socket_state(&mut self, w: &mut dyn Write, state: &SocketStateSpec) -> std::io::Result<()> {
+ writeln!(w, "\nSocket State Requirements:")?;
+ if !state.required_states.is_empty() {
+ writeln!(w, " Required states: {:?}", state.required_states)?;
+ }
+ if !state.forbidden_states.is_empty() {
+ writeln!(w, " Forbidden states: {:?}", state.forbidden_states)?;
+ }
+ if let Some(result) = &state.resulting_state {
+ writeln!(w, " Resulting state: {result}")?;
+ }
+ if let Some(cond) = &state.condition {
+ writeln!(w, " Condition: {cond}")?;
+ }
+ if let Some(protos) = &state.applicable_protocols {
+ writeln!(w, " Applicable protocols: {protos}")?;
+ }
+ Ok(())
+ }
+
+ fn begin_protocol_behaviors(&mut self, w: &mut dyn Write) -> std::io::Result<()> {
+ writeln!(w, "\nProtocol-Specific Behaviors:")
+ }
+
+ fn protocol_behavior(
+ &mut self,
+ w: &mut dyn Write,
+ behavior: &ProtocolBehaviorSpec,
+ ) -> std::io::Result<()> {
+ writeln!(
+ w,
+ " {} - {}",
+ behavior.applicable_protocols, behavior.behavior
+ )?;
+ if let Some(flags) = &behavior.protocol_flags {
+ writeln!(w, " Flags: {flags}")?;
+ }
+ Ok(())
+ }
+
+ fn end_protocol_behaviors(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_addr_families(&mut self, w: &mut dyn Write) -> std::io::Result<()> {
+ writeln!(w, "\nSupported Address Families:")
+ }
+
+ fn addr_family(&mut self, w: &mut dyn Write, family: &AddrFamilySpec) -> std::io::Result<()> {
+ writeln!(w, " {} ({}):", family.family_name, family.family)?;
+ writeln!(w, " Struct size: {} bytes", family.addr_struct_size)?;
+ writeln!(
+ w,
+ " Address length: {}-{} bytes",
+ family.min_addr_len, family.max_addr_len
+ )?;
+ if let Some(format) = &family.addr_format {
+ writeln!(w, " Format: {format}")?;
+ }
+ writeln!(
+ w,
+ " Features: wildcard={}, multicast={}, broadcast={}",
+ family.supports_wildcard, family.supports_multicast, family.supports_broadcast
+ )?;
+ if let Some(special) = &family.special_addresses {
+ writeln!(w, " Special addresses: {special}")?;
+ }
+ if family.port_range_max > 0 {
+ writeln!(
+ w,
+ " Port range: {}-{}",
+ family.port_range_min, family.port_range_max
+ )?;
+ }
+ Ok(())
+ }
+
+ fn end_addr_families(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn buffer_spec(&mut self, w: &mut dyn Write, spec: &BufferSpec) -> std::io::Result<()> {
+ writeln!(w, "\nBuffer Specification:")?;
+ if let Some(behaviors) = &spec.buffer_behaviors {
+ writeln!(w, " Behaviors: {behaviors}")?;
+ }
+ if let Some(min) = spec.min_buffer_size {
+ writeln!(w, " Min size: {min} bytes")?;
+ }
+ if let Some(max) = spec.max_buffer_size {
+ writeln!(w, " Max size: {max} bytes")?;
+ }
+ if let Some(optimal) = spec.optimal_buffer_size {
+ writeln!(w, " Optimal size: {optimal} bytes")?;
+ }
+ Ok(())
+ }
+
+ fn async_spec(&mut self, w: &mut dyn Write, spec: &AsyncSpec) -> std::io::Result<()> {
+ writeln!(w, "\nAsynchronous Operation:")?;
+ if let Some(modes) = &spec.supported_modes {
+ writeln!(w, " Supported modes: {modes}")?;
+ }
+ if let Some(errno) = spec.nonblock_errno {
+ writeln!(w, " Non-blocking errno: {errno}")?;
+ }
+ Ok(())
+ }
+
+ fn net_data_transfer(&mut self, w: &mut dyn Write, desc: &str) -> std::io::Result<()> {
+ writeln!(w, "\nNetwork Data Transfer: {desc}")
+ }
+
+ fn begin_capabilities(&mut self, w: &mut dyn Write) -> std::io::Result<()> {
+ writeln!(w, "\nRequired Capabilities:")
+ }
+
+ fn capability(&mut self, w: &mut dyn Write, cap: &CapabilitySpec) -> std::io::Result<()> {
+ writeln!(w, " {} ({}) - {}", cap.name, cap.capability, cap.action)?;
+ if !cap.allows.is_empty() {
+ writeln!(w, " Allows: {}", cap.allows)?;
+ }
+ if !cap.without_cap.is_empty() {
+ writeln!(w, " Without capability: {}", cap.without_cap)?;
+ }
+ if let Some(cond) = &cap.check_condition {
+ writeln!(w, " Condition: {cond}")?;
+ }
+ Ok(())
+ }
+
+ fn end_capabilities(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ // Signal-related methods
+ fn begin_signals(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+ writeln!(w, "\nSignal Specifications ({count}):")
+ }
+
+ fn signal(&mut self, w: &mut dyn Write, signal: &SignalSpec) -> std::io::Result<()> {
+ write!(w, " {} ({})", signal.signal_name, signal.signal_num)?;
+
+ // Display direction (bitmask matching C enum kapi_signal_direction)
+ let mut dirs = Vec::new();
+ if signal.direction & 1 != 0 { dirs.push("RECEIVE"); }
+ if signal.direction & 2 != 0 { dirs.push("SEND"); }
+ if signal.direction & 4 != 0 { dirs.push("HANDLE"); }
+ if signal.direction & 8 != 0 { dirs.push("BLOCK"); }
+ if signal.direction & 16 != 0 { dirs.push("IGNORE"); }
+ let direction = if dirs.is_empty() { "UNKNOWN".to_string() } else { dirs.join("|") };
+ write!(w, " - {direction}")?;
+
+ // Display action (matching C enum kapi_signal_action)
+ let action = match signal.action {
+ 0 => "DEFAULT",
+ 1 => "TERMINATE",
+ 2 => "COREDUMP",
+ 3 => "STOP",
+ 4 => "CONTINUE",
+ 5 => "CUSTOM",
+ 6 => "RETURN",
+ 7 => "RESTART",
+ 8 => "QUEUE",
+ 9 => "DISCARD",
+ 10 => "TRANSFORM",
+ _ => "UNKNOWN",
+ };
+ writeln!(w, " - {action}")?;
+
+ if let Some(target) = &signal.target {
+ writeln!(w, " Target: {target}")?;
+ }
+ if let Some(condition) = &signal.condition {
+ writeln!(w, " Condition: {condition}")?;
+ }
+ if let Some(desc) = &signal.description {
+ writeln!(w, " {desc}")?;
+ }
+
+ // Display timing
+ let timing = match signal.timing {
+ 0 => "BEFORE",
+ 1 => "DURING",
+ 2 => "AFTER",
+ 3 => "EXIT",
+ _ => "UNKNOWN",
+ };
+ writeln!(w, " Timing: {timing}")?;
+ writeln!(w, " Priority: {}", signal.priority)?;
+
+ if signal.restartable {
+ writeln!(w, " Restartable: yes")?;
+ }
+ if signal.interruptible {
+ writeln!(w, " Interruptible: yes")?;
+ }
+ if let Some(error) = signal.error_on_signal {
+ writeln!(w, " Error on signal: {error}")?;
+ }
+ Ok(())
+ }
+
+ fn end_signals(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_signal_masks(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+ writeln!(w, "\nSignal Masks ({count}):")
+ }
+
+ fn signal_mask(&mut self, w: &mut dyn Write, mask: &SignalMaskSpec) -> std::io::Result<()> {
+ writeln!(w, " {}", mask.name)?;
+ if !mask.description.is_empty() {
+ writeln!(w, " {}", mask.description)?;
+ }
+ Ok(())
+ }
+
+ fn end_signal_masks(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ // Side effects and state transitions
+ fn begin_side_effects(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+ writeln!(w, "\nSide Effects ({count}):")
+ }
+
+ fn side_effect(&mut self, w: &mut dyn Write, effect: &SideEffectSpec) -> std::io::Result<()> {
+ writeln!(w, " {} - {}", effect.target, effect.description)?;
+ if let Some(condition) = &effect.condition {
+ writeln!(w, " Condition: {condition}")?;
+ }
+ if effect.reversible {
+ writeln!(w, " Reversible: yes")?;
+ }
+ Ok(())
+ }
+
+ fn end_side_effects(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_state_transitions(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+ writeln!(w, "\nState Transitions ({count}):")
+ }
+
+ fn state_transition(
+ &mut self,
+ w: &mut dyn Write,
+ trans: &StateTransitionSpec,
+ ) -> std::io::Result<()> {
+ writeln!(
+ w,
+ " {} : {} -> {}",
+ trans.object, trans.from_state, trans.to_state
+ )?;
+ if let Some(condition) = &trans.condition {
+ writeln!(w, " Condition: {condition}")?;
+ }
+ if !trans.description.is_empty() {
+ writeln!(w, " {}", trans.description)?;
+ }
+ Ok(())
+ }
+
+ fn end_state_transitions(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ // Constraints and locks
+ fn begin_constraints(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+ writeln!(w, "\nAdditional Constraints ({count}):")
+ }
+
+ fn constraint(
+ &mut self,
+ w: &mut dyn Write,
+ constraint: &ConstraintSpec,
+ ) -> std::io::Result<()> {
+ writeln!(w, " {}", constraint.name)?;
+ if !constraint.description.is_empty() {
+ writeln!(w, " {}", constraint.description)?;
+ }
+ if let Some(expr) = &constraint.expression {
+ writeln!(w, " Expression: {expr}")?;
+ }
+ Ok(())
+ }
+
+ fn end_constraints(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_locks(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+ writeln!(w, "\nLocking Requirements ({count}):")
+ }
+
+ fn lock(&mut self, w: &mut dyn Write, lock: &LockSpec) -> std::io::Result<()> {
+ write!(w, " {}", lock.lock_name)?;
+
+ // Display lock type
+ let lock_type = match lock.lock_type {
+ 0 => "NONE",
+ 1 => "MUTEX",
+ 2 => "SPINLOCK",
+ 3 => "RWLOCK",
+ 4 => "SEQLOCK",
+ 5 => "RCU",
+ 6 => "SEMAPHORE",
+ 7 => "CUSTOM",
+ _ => "UNKNOWN",
+ };
+ writeln!(w, " ({lock_type})")?;
+
+ let scope_str = match lock.scope {
+ 0 => "acquired and released",
+ 1 => "acquired (not released)",
+ 2 => "released (held on entry)",
+ 3 => "held by caller",
+ _ => "unknown",
+ };
+ writeln!(w, " Scope: {scope_str}")?;
+
+ if !lock.description.is_empty() {
+ writeln!(w, " {}", lock.description)?;
+ }
+ Ok(())
+ }
+
+ fn end_locks(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_struct_specs(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+ writeln!(w, "\nStructure Specifications ({count}):")
+ }
+
+ fn struct_spec(&mut self, w: &mut dyn Write, spec: &crate::extractor::StructSpec) -> std::io::Result<()> {
+ writeln!(w, " {} (size={}, align={}):", spec.name, spec.size, spec.alignment)?;
+ if !spec.description.is_empty() {
+ writeln!(w, " {}", spec.description)?;
+ }
+
+ if !spec.fields.is_empty() {
+ writeln!(w, " Fields ({}):", spec.field_count)?;
+ for field in &spec.fields {
+ write!(w, " - {} ({}):", field.name, field.type_name)?;
+ if !field.description.is_empty() {
+ write!(w, " {}", field.description)?;
+ }
+ writeln!(w)?;
+
+ // Show constraints if present
+ if field.min_value != 0 || field.max_value != 0 {
+ writeln!(w, " Range: [{}, {}]", field.min_value, field.max_value)?;
+ }
+ if field.valid_mask != 0 {
+ writeln!(w, " Mask: {:#x}", field.valid_mask)?;
+ }
+ }
+ }
+ Ok(())
+ }
+
+ fn end_struct_specs(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+ use crate::extractor::{ErrorSpec, ParamSpec, ReturnSpec};
+
+ fn render_plain(f: &mut PlainFormatter, sink: &mut Vec<u8>) -> String {
+ f.end_document(sink).unwrap();
+ String::from_utf8(sink.clone()).unwrap()
+ }
+
+ #[test]
+ fn plain_api_list() {
+ let mut f = PlainFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_list(&mut sink, "System Calls").unwrap();
+ f.api_item(&mut sink, "sys_open", "syscall").unwrap();
+ f.api_item(&mut sink, "sys_read", "syscall").unwrap();
+ f.end_api_list(&mut sink).unwrap();
+ f.total_specs(&mut sink, 2).unwrap();
+
+ let out = render_plain(&mut f, &mut sink);
+ assert!(out.contains("sys_open"));
+ assert!(out.contains("sys_read"));
+ assert!(out.contains("Total specifications found: 2"));
+ }
+
+ #[test]
+ fn plain_api_details() {
+ let mut f = PlainFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_test").unwrap();
+ f.description(&mut sink, "A test syscall").unwrap();
+ f.long_description(&mut sink, "Detailed description here").unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let out = render_plain(&mut f, &mut sink);
+ assert!(out.contains("sys_test"));
+ assert!(out.contains("A test syscall"));
+ assert!(out.contains("Detailed description here"));
+ }
+
+ #[test]
+ fn plain_parameters() {
+ let mut f = PlainFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_write").unwrap();
+ f.begin_parameters(&mut sink, 1).unwrap();
+ f.parameter(
+ &mut sink,
+ &ParamSpec {
+ index: 0,
+ name: "fd".to_string(),
+ type_name: "unsigned int".to_string(),
+ description: "file descriptor".to_string(),
+ flags: 1,
+ param_type: 2,
+ constraint_type: 0,
+ constraint: None,
+ min_value: None,
+ max_value: None,
+ valid_mask: None,
+ enum_values: vec![],
+ size: None,
+ alignment: None,
+ },
+ )
+ .unwrap();
+ f.end_parameters(&mut sink).unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let out = render_plain(&mut f, &mut sink);
+ assert!(out.contains("fd"));
+ assert!(out.contains("unsigned int"));
+ assert!(out.contains("file descriptor"));
+ }
+
+ #[test]
+ fn plain_errors() {
+ let mut f = PlainFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_test").unwrap();
+ f.begin_errors(&mut sink, 1).unwrap();
+ f.error(
+ &mut sink,
+ &ErrorSpec {
+ error_code: -2,
+ name: "ENOENT".to_string(),
+ condition: "File not found".to_string(),
+ description: "The file does not exist".to_string(),
+ },
+ )
+ .unwrap();
+ f.end_errors(&mut sink).unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let out = render_plain(&mut f, &mut sink);
+ assert!(out.contains("ENOENT"));
+ assert!(out.contains("-2"));
+ assert!(out.contains("File not found"));
+ }
+
+ #[test]
+ fn plain_return_spec() {
+ let mut f = PlainFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_test").unwrap();
+ f.return_spec(
+ &mut sink,
+ &ReturnSpec {
+ type_name: "KAPI_TYPE_INT".to_string(),
+ description: "Returns 0 on success".to_string(),
+ return_type: 1,
+ check_type: 0,
+ success_value: Some(0),
+ success_min: None,
+ success_max: None,
+ error_values: vec![],
+ },
+ )
+ .unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let out = render_plain(&mut f, &mut sink);
+ assert!(out.contains("KAPI_TYPE_INT"));
+ assert!(out.contains("Returns 0 on success"));
+ }
+
+ #[test]
+ fn plain_context_flags() {
+ let mut f = PlainFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_test").unwrap();
+ f.begin_context_flags(&mut sink).unwrap();
+ f.context_flag(&mut sink, "KAPI_CTX_PROCESS").unwrap();
+ f.context_flag(&mut sink, "KAPI_CTX_SLEEPABLE").unwrap();
+ f.end_context_flags(&mut sink).unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let out = render_plain(&mut f, &mut sink);
+ assert!(out.contains("KAPI_CTX_PROCESS"));
+ assert!(out.contains("KAPI_CTX_SLEEPABLE"));
+ }
+}
diff --git a/tools/kapi/src/formatter/rst.rs b/tools/kapi/src/formatter/rst.rs
new file mode 100644
index 0000000000000..61df4d8944fef
--- /dev/null
+++ b/tools/kapi/src/formatter/rst.rs
@@ -0,0 +1,850 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2026 Sasha Levin <sashal@kernel.org>
+
+use super::OutputFormatter;
+use crate::extractor::{
+ AddrFamilySpec, AsyncSpec, BufferSpec, CapabilitySpec, ConstraintSpec, ErrorSpec, LockSpec,
+ ParamSpec, ProtocolBehaviorSpec, ReturnSpec, SideEffectSpec, SignalMaskSpec, SignalSpec,
+ SocketStateSpec, StateTransitionSpec,
+};
+use std::io::Write;
+
+pub struct RstFormatter;
+
+impl RstFormatter {
+ pub fn new() -> Self {
+ RstFormatter
+ }
+
+ fn section_char(level: usize) -> char {
+ match level {
+ 0 => '=',
+ 1 => '-',
+ 2 => '~',
+ 3 => '^',
+ _ => '"',
+ }
+ }
+}
+
+impl OutputFormatter for RstFormatter {
+ fn begin_document(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn end_document(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_api_list(&mut self, w: &mut dyn Write, title: &str) -> std::io::Result<()> {
+ writeln!(w, "\n{title}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(0).to_string().repeat(title.len())
+ )?;
+ writeln!(w)
+ }
+
+ fn api_item(&mut self, w: &mut dyn Write, name: &str, api_type: &str) -> std::io::Result<()> {
+ writeln!(w, "* **{name}** (*{api_type}*)")
+ }
+
+ fn end_api_list(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn total_specs(&mut self, w: &mut dyn Write, count: usize) -> std::io::Result<()> {
+ writeln!(w, "\n**Total specifications found:** {count}")
+ }
+
+ fn begin_api_details(&mut self, w: &mut dyn Write, name: &str) -> std::io::Result<()> {
+
+ writeln!(w, "\n{name}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(0).to_string().repeat(name.len())
+ )?;
+ writeln!(w)
+ }
+
+ fn end_api_details(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn description(&mut self, w: &mut dyn Write, desc: &str) -> std::io::Result<()> {
+ writeln!(w, "**{desc}**")?;
+ writeln!(w)
+ }
+
+ fn long_description(&mut self, w: &mut dyn Write, desc: &str) -> std::io::Result<()> {
+ writeln!(w, "{desc}")?;
+ writeln!(w)
+ }
+
+ fn begin_context_flags(&mut self, w: &mut dyn Write) -> std::io::Result<()> {
+
+ let title = "Execution Context";
+ writeln!(w, "{title}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(1).to_string().repeat(title.len())
+ )?;
+ writeln!(w)
+ }
+
+ fn context_flag(&mut self, w: &mut dyn Write, flag: &str) -> std::io::Result<()> {
+ writeln!(w, "* {flag}")
+ }
+
+ fn end_context_flags(&mut self, w: &mut dyn Write) -> std::io::Result<()> {
+ writeln!(w)
+ }
+
+ fn begin_parameters(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+
+ let title = format!("Parameters ({count})");
+ writeln!(w, "{title}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(1).to_string().repeat(title.len())
+ )?;
+ writeln!(w)
+ }
+
+ fn end_parameters(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_errors(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+
+ let title = format!("Possible Errors ({count})");
+ writeln!(w, "{title}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(1).to_string().repeat(title.len())
+ )?;
+ writeln!(w)
+ }
+
+ fn end_errors(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn examples(&mut self, w: &mut dyn Write, examples: &str) -> std::io::Result<()> {
+
+ let title = "Examples";
+ writeln!(w, "{title}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(1).to_string().repeat(title.len())
+ )?;
+ writeln!(w)?;
+ writeln!(w, ".. code-block:: c")?;
+ writeln!(w)?;
+ for line in examples.lines() {
+ writeln!(w, " {line}")?;
+ }
+ writeln!(w)
+ }
+
+ fn notes(&mut self, w: &mut dyn Write, notes: &str) -> std::io::Result<()> {
+
+ let title = "Notes";
+ writeln!(w, "{title}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(1).to_string().repeat(title.len())
+ )?;
+ writeln!(w)?;
+ writeln!(w, "{notes}")?;
+ writeln!(w)
+ }
+
+ fn sysfs_subsystem(&mut self, w: &mut dyn Write, subsystem: &str) -> std::io::Result<()> {
+ writeln!(w, ":Subsystem: {subsystem}")?;
+ writeln!(w)
+ }
+
+ fn sysfs_path(&mut self, w: &mut dyn Write, path: &str) -> std::io::Result<()> {
+ writeln!(w, ":Sysfs Path: {path}")?;
+ writeln!(w)
+ }
+
+ fn sysfs_permissions(&mut self, w: &mut dyn Write, perms: &str) -> std::io::Result<()> {
+ writeln!(w, ":Permissions: {perms}")?;
+ writeln!(w)
+ }
+
+ // Networking-specific methods
+ fn socket_state(&mut self, w: &mut dyn Write, state: &SocketStateSpec) -> std::io::Result<()> {
+
+ let title = "Socket State Requirements";
+ writeln!(w, "{title}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(1).to_string().repeat(title.len())
+ )?;
+ writeln!(w)?;
+
+ if !state.required_states.is_empty() {
+ writeln!(
+ w,
+ "**Required states:** {}",
+ state.required_states.join(", ")
+ )?;
+ }
+ if !state.forbidden_states.is_empty() {
+ writeln!(
+ w,
+ "**Forbidden states:** {}",
+ state.forbidden_states.join(", ")
+ )?;
+ }
+ if let Some(result) = &state.resulting_state {
+ writeln!(w, "**Resulting state:** {result}")?;
+ }
+ if let Some(cond) = &state.condition {
+ writeln!(w, "**Condition:** {cond}")?;
+ }
+ if let Some(protos) = &state.applicable_protocols {
+ writeln!(w, "**Applicable protocols:** {protos}")?;
+ }
+ writeln!(w)
+ }
+
+ fn begin_protocol_behaviors(&mut self, w: &mut dyn Write) -> std::io::Result<()> {
+
+ let title = "Protocol-Specific Behaviors";
+ writeln!(w, "{title}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(1).to_string().repeat(title.len())
+ )?;
+ writeln!(w)
+ }
+
+ fn protocol_behavior(
+ &mut self,
+ w: &mut dyn Write,
+ behavior: &ProtocolBehaviorSpec,
+ ) -> std::io::Result<()> {
+ writeln!(w, "**{}**", behavior.applicable_protocols)?;
+ writeln!(w)?;
+ writeln!(w, "{}", behavior.behavior)?;
+ if let Some(flags) = &behavior.protocol_flags {
+ writeln!(w)?;
+ writeln!(w, "*Flags:* {flags}")?;
+ }
+ writeln!(w)
+ }
+
+ fn end_protocol_behaviors(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_addr_families(&mut self, w: &mut dyn Write) -> std::io::Result<()> {
+
+ let title = "Supported Address Families";
+ writeln!(w, "{title}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(1).to_string().repeat(title.len())
+ )?;
+ writeln!(w)
+ }
+
+ fn addr_family(&mut self, w: &mut dyn Write, family: &AddrFamilySpec) -> std::io::Result<()> {
+ writeln!(w, "**{} ({})**", family.family_name, family.family)?;
+ writeln!(w)?;
+ writeln!(w, "* **Struct size:** {} bytes", family.addr_struct_size)?;
+ writeln!(
+ w,
+ "* **Address length:** {}-{} bytes",
+ family.min_addr_len, family.max_addr_len
+ )?;
+ if let Some(format) = &family.addr_format {
+ writeln!(w, "* **Format:** ``{format}``")?;
+ }
+ writeln!(
+ w,
+ "* **Features:** wildcard={}, multicast={}, broadcast={}",
+ family.supports_wildcard, family.supports_multicast, family.supports_broadcast
+ )?;
+ if let Some(special) = &family.special_addresses {
+ writeln!(w, "* **Special addresses:** {special}")?;
+ }
+ if family.port_range_max > 0 {
+ writeln!(
+ w,
+ "* **Port range:** {}-{}",
+ family.port_range_min, family.port_range_max
+ )?;
+ }
+ writeln!(w)
+ }
+
+ fn end_addr_families(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn buffer_spec(&mut self, w: &mut dyn Write, spec: &BufferSpec) -> std::io::Result<()> {
+
+ let title = "Buffer Specification";
+ writeln!(w, "{title}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(1).to_string().repeat(title.len())
+ )?;
+ writeln!(w)?;
+
+ if let Some(behaviors) = &spec.buffer_behaviors {
+ writeln!(w, "**Behaviors:** {behaviors}")?;
+ }
+ if let Some(min) = spec.min_buffer_size {
+ writeln!(w, "**Min size:** {min} bytes")?;
+ }
+ if let Some(max) = spec.max_buffer_size {
+ writeln!(w, "**Max size:** {max} bytes")?;
+ }
+ if let Some(optimal) = spec.optimal_buffer_size {
+ writeln!(w, "**Optimal size:** {optimal} bytes")?;
+ }
+ writeln!(w)
+ }
+
+ fn async_spec(&mut self, w: &mut dyn Write, spec: &AsyncSpec) -> std::io::Result<()> {
+
+ let title = "Asynchronous Operation";
+ writeln!(w, "{title}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(1).to_string().repeat(title.len())
+ )?;
+ writeln!(w)?;
+
+ if let Some(modes) = &spec.supported_modes {
+ writeln!(w, "**Supported modes:** {modes}")?;
+ }
+ if let Some(errno) = spec.nonblock_errno {
+ writeln!(w, "**Non-blocking errno:** {errno}")?;
+ }
+ writeln!(w)
+ }
+
+ fn net_data_transfer(&mut self, w: &mut dyn Write, desc: &str) -> std::io::Result<()> {
+ writeln!(w, "**Network Data Transfer:** {desc}")?;
+ writeln!(w)
+ }
+
+ fn begin_capabilities(&mut self, w: &mut dyn Write) -> std::io::Result<()> {
+
+ let title = "Required Capabilities";
+ writeln!(w, "{title}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(1).to_string().repeat(title.len())
+ )?;
+ writeln!(w)
+ }
+
+ fn capability(&mut self, w: &mut dyn Write, cap: &CapabilitySpec) -> std::io::Result<()> {
+ writeln!(w, "**{} ({})** - {}", cap.name, cap.capability, cap.action)?;
+ writeln!(w)?;
+ if !cap.allows.is_empty() {
+ writeln!(w, "* **Allows:** {}", cap.allows)?;
+ }
+ if !cap.without_cap.is_empty() {
+ writeln!(w, "* **Without capability:** {}", cap.without_cap)?;
+ }
+ if let Some(cond) = &cap.check_condition {
+ writeln!(w, "* **Condition:** {}", cond)?;
+ }
+ writeln!(w)
+ }
+
+ fn end_capabilities(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn parameter(&mut self, w: &mut dyn Write, param: &ParamSpec) -> std::io::Result<()> {
+ writeln!(
+ w,
+ "**[{}] {}** (*{}*)",
+ param.index, param.name, param.type_name
+ )?;
+ writeln!(w)?;
+ writeln!(w, " {}", param.description)?;
+
+ // Display flags
+ let mut flags = Vec::new();
+ if param.flags & 0x01 != 0 {
+ flags.push("IN");
+ }
+ if param.flags & 0x02 != 0 {
+ flags.push("OUT");
+ }
+ if param.flags & 0x04 != 0 {
+ flags.push("USER");
+ }
+ if param.flags & 0x08 != 0 {
+ flags.push("OPTIONAL");
+ }
+ if !flags.is_empty() {
+ writeln!(w, " :Flags: {}", flags.join(", "))?;
+ }
+
+ if let Some(constraint) = &param.constraint {
+ writeln!(w, " :Constraint: {}", constraint)?;
+ }
+
+ if let (Some(min), Some(max)) = (param.min_value, param.max_value) {
+ writeln!(w, " :Range: {} to {}", min, max)?;
+ }
+
+ writeln!(w)
+ }
+
+ fn return_spec(&mut self, w: &mut dyn Write, ret: &ReturnSpec) -> std::io::Result<()> {
+ writeln!(w, "\nReturn Value")?;
+ writeln!(w, "{}\n", Self::section_char(1).to_string().repeat(12))?;
+ writeln!(w)?;
+ writeln!(w, ":Type: {}", ret.type_name)?;
+ writeln!(w, ":Description: {}", ret.description)?;
+ if let Some(success) = ret.success_value {
+ writeln!(w, ":Success value: {}", success)?;
+ }
+ writeln!(w)
+ }
+
+ fn error(&mut self, w: &mut dyn Write, error: &ErrorSpec) -> std::io::Result<()> {
+ writeln!(w, "**{}** ({})", error.name, error.error_code)?;
+ writeln!(w)?;
+ writeln!(w, " :Condition: {}", error.condition)?;
+ if !error.description.is_empty() {
+ writeln!(w, " :Description: {}", error.description)?;
+ }
+ writeln!(w)
+ }
+
+ fn begin_signals(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+
+ let title = format!("Signals ({count})");
+ writeln!(w, "{title}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(1).to_string().repeat(title.len())
+ )?;
+ writeln!(w)
+ }
+
+ fn signal(&mut self, w: &mut dyn Write, signal: &SignalSpec) -> std::io::Result<()> {
+ write!(w, "* **{}**", signal.signal_name)?;
+ if signal.signal_num != 0 {
+ write!(w, " ({})", signal.signal_num)?;
+ }
+ writeln!(w)?;
+
+ // Direction (bitmask matching C enum kapi_signal_direction)
+ let mut dirs = Vec::new();
+ if signal.direction & 1 != 0 { dirs.push("receive"); }
+ if signal.direction & 2 != 0 { dirs.push("send"); }
+ if signal.direction & 4 != 0 { dirs.push("handle"); }
+ if signal.direction & 8 != 0 { dirs.push("block"); }
+ if signal.direction & 16 != 0 { dirs.push("ignore"); }
+ let direction = if dirs.is_empty() { "unknown".to_string() } else { dirs.join(", ") };
+ writeln!(w, " :Direction: {}", direction)?;
+
+ // Action (matching C enum kapi_signal_action)
+ let action = match signal.action {
+ 0 => "default",
+ 1 => "terminate",
+ 2 => "coredump",
+ 3 => "stop",
+ 4 => "continue",
+ 5 => "custom",
+ 6 => "return",
+ 7 => "restart",
+ 8 => "queue",
+ 9 => "discard",
+ 10 => "transform",
+ _ => "unknown",
+ };
+ writeln!(w, " :Action: {}", action)?;
+
+ if let Some(cond) = &signal.condition {
+ writeln!(w, " :Condition: {}", cond)?;
+ }
+ if let Some(desc) = &signal.description {
+ writeln!(w, " :Description: {}", desc)?;
+ }
+ if signal.interruptible {
+ writeln!(w, " :Interruptible: yes")?;
+ }
+ if signal.restartable {
+ writeln!(w, " :Restartable: yes")?;
+ }
+ writeln!(w)
+ }
+
+ fn end_signals(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_signal_masks(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+
+ let title = format!("Signal Masks ({count})");
+ writeln!(w, "{title}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(1).to_string().repeat(title.len())
+ )?;
+ writeln!(w)
+ }
+
+ fn signal_mask(&mut self, w: &mut dyn Write, mask: &SignalMaskSpec) -> std::io::Result<()> {
+ writeln!(w, "* **{}**", mask.name)?;
+ if !mask.description.is_empty() {
+ writeln!(w, " {}", mask.description)?;
+ }
+ writeln!(w)
+ }
+
+ fn end_signal_masks(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_side_effects(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+
+ let title = format!("Side Effects ({count})");
+ writeln!(w, "{}\n", title)?;
+ writeln!(
+ w,
+ "{}\n",
+ Self::section_char(1).to_string().repeat(title.len())
+ )
+ }
+
+ fn side_effect(&mut self, w: &mut dyn Write, effect: &SideEffectSpec) -> std::io::Result<()> {
+ write!(w, "* **{}**", effect.target)?;
+ if effect.reversible {
+ write!(w, " *(reversible)*")?;
+ }
+ writeln!(w)?;
+ writeln!(w, " {}", effect.description)?;
+ if let Some(cond) = &effect.condition {
+ writeln!(w, " :Condition: {}", cond)?;
+ }
+ writeln!(w)
+ }
+
+ fn end_side_effects(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_state_transitions(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+
+ let title = format!("State Transitions ({count})");
+ writeln!(w, "{}\n", title)?;
+ writeln!(
+ w,
+ "{}\n",
+ Self::section_char(1).to_string().repeat(title.len())
+ )
+ }
+
+ fn state_transition(
+ &mut self,
+ w: &mut dyn Write,
+ trans: &StateTransitionSpec,
+ ) -> std::io::Result<()> {
+ writeln!(
+ w,
+ "* **{}**: {} → {}",
+ trans.object, trans.from_state, trans.to_state
+ )?;
+ writeln!(w, " {}", trans.description)?;
+ if let Some(cond) = &trans.condition {
+ writeln!(w, " :Condition: {}", cond)?;
+ }
+ writeln!(w)
+ }
+
+ fn end_state_transitions(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_constraints(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+
+ let title = format!("Constraints ({count})");
+ writeln!(w, "{title}")?;
+ writeln!(
+ w,
+ "{}",
+ Self::section_char(1).to_string().repeat(title.len())
+ )?;
+ writeln!(w)
+ }
+
+ fn constraint(
+ &mut self,
+ w: &mut dyn Write,
+ constraint: &ConstraintSpec,
+ ) -> std::io::Result<()> {
+ writeln!(w, "* **{}**", constraint.name)?;
+ if !constraint.description.is_empty() {
+ writeln!(w, " {}", constraint.description)?;
+ }
+ if let Some(expr) = &constraint.expression {
+ writeln!(w, " :Expression: ``{}``", expr)?;
+ }
+ writeln!(w)
+ }
+
+ fn end_constraints(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_locks(&mut self, w: &mut dyn Write, count: u32) -> std::io::Result<()> {
+
+ let title = format!("Locks ({count})");
+ writeln!(w, "{}\n", title)?;
+ writeln!(
+ w,
+ "{}\n",
+ Self::section_char(1).to_string().repeat(title.len())
+ )
+ }
+
+ fn lock(&mut self, w: &mut dyn Write, lock: &LockSpec) -> std::io::Result<()> {
+ write!(w, "* **{}**", lock.lock_name)?;
+ let lock_type_str = match lock.lock_type {
+ 1 => " *(mutex)*",
+ 2 => " *(spinlock)*",
+ 3 => " *(rwlock)*",
+ 4 => " *(semaphore)*",
+ 5 => " *(RCU)*",
+ _ => "",
+ };
+ writeln!(w, "{}", lock_type_str)?;
+ if !lock.description.is_empty() {
+ writeln!(w, " {}", lock.description)?;
+ }
+ writeln!(w)
+ }
+
+ fn end_locks(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+
+ fn begin_struct_specs(&mut self, w: &mut dyn Write, _count: u32) -> std::io::Result<()> {
+ writeln!(w)?;
+ writeln!(w, "Structure Specifications")?;
+ writeln!(w, "~~~~~~~~~~~~~~~~~~~~~~~")?;
+ writeln!(w)
+ }
+
+ fn struct_spec(&mut self, w: &mut dyn Write, spec: &crate::extractor::StructSpec) -> std::io::Result<()> {
+ writeln!(w, "**{}**", spec.name)?;
+ writeln!(w)?;
+
+ if !spec.description.is_empty() {
+ writeln!(w, " {}", spec.description)?;
+ writeln!(w)?;
+ }
+
+ writeln!(w, " :Size: {} bytes", spec.size)?;
+ writeln!(w, " :Alignment: {} bytes", spec.alignment)?;
+ writeln!(w, " :Fields: {}", spec.field_count)?;
+ writeln!(w)?;
+
+ if !spec.fields.is_empty() {
+ for field in &spec.fields {
+ writeln!(w, " * **{}** ({})", field.name, field.type_name)?;
+ if !field.description.is_empty() {
+ writeln!(w, " {}", field.description)?;
+ }
+ if field.min_value != 0 || field.max_value != 0 {
+ writeln!(w, " Range: [{}, {}]", field.min_value, field.max_value)?;
+ }
+ }
+ writeln!(w)?;
+ }
+
+ Ok(())
+ }
+
+ fn end_struct_specs(&mut self, _w: &mut dyn Write) -> std::io::Result<()> {
+ Ok(())
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+ use crate::extractor::{ErrorSpec, ParamSpec, ReturnSpec};
+
+ fn render_rst(f: &mut RstFormatter, sink: &mut Vec<u8>) -> String {
+ f.end_document(sink).unwrap();
+ String::from_utf8(sink.clone()).unwrap()
+ }
+
+ #[test]
+ fn rst_api_details_has_heading() {
+ let mut f = RstFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_test").unwrap();
+ f.description(&mut sink, "A test syscall").unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let out = render_rst(&mut f, &mut sink);
+ assert!(out.contains("sys_test"));
+ assert!(out.contains("========"));
+ assert!(out.contains("**A test syscall**"));
+ }
+
+ #[test]
+ fn rst_api_list() {
+ let mut f = RstFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_list(&mut sink, "System Calls").unwrap();
+ f.api_item(&mut sink, "sys_open", "syscall").unwrap();
+ f.api_item(&mut sink, "sys_read", "syscall").unwrap();
+ f.end_api_list(&mut sink).unwrap();
+ f.total_specs(&mut sink, 2).unwrap();
+
+ let out = render_rst(&mut f, &mut sink);
+ assert!(out.contains("sys_open"));
+ assert!(out.contains("sys_read"));
+ }
+
+ #[test]
+ fn rst_parameters() {
+ let mut f = RstFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_write").unwrap();
+ f.begin_parameters(&mut sink, 1).unwrap();
+ f.parameter(
+ &mut sink,
+ &ParamSpec {
+ index: 0,
+ name: "fd".to_string(),
+ type_name: "unsigned int".to_string(),
+ description: "file descriptor".to_string(),
+ flags: 1,
+ param_type: 2,
+ constraint_type: 0,
+ constraint: None,
+ min_value: None,
+ max_value: None,
+ valid_mask: None,
+ enum_values: vec![],
+ size: None,
+ alignment: None,
+ },
+ )
+ .unwrap();
+ f.end_parameters(&mut sink).unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let out = render_rst(&mut f, &mut sink);
+ assert!(out.contains("**[0] fd**"));
+ assert!(out.contains("unsigned int"));
+ assert!(out.contains("file descriptor"));
+ }
+
+ #[test]
+ fn rst_errors() {
+ let mut f = RstFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_test").unwrap();
+ f.begin_errors(&mut sink, 1).unwrap();
+ f.error(
+ &mut sink,
+ &ErrorSpec {
+ error_code: -2,
+ name: "ENOENT".to_string(),
+ condition: "File not found".to_string(),
+ description: "The file does not exist".to_string(),
+ },
+ )
+ .unwrap();
+ f.end_errors(&mut sink).unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let out = render_rst(&mut f, &mut sink);
+ assert!(out.contains("**ENOENT**"));
+ assert!(out.contains("-2"));
+ assert!(out.contains("File not found"));
+ }
+
+ #[test]
+ fn rst_return_spec() {
+ let mut f = RstFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_test").unwrap();
+ f.return_spec(
+ &mut sink,
+ &ReturnSpec {
+ type_name: "KAPI_TYPE_INT".to_string(),
+ description: "Returns 0 on success".to_string(),
+ return_type: 1,
+ check_type: 0,
+ success_value: Some(0),
+ success_min: None,
+ success_max: None,
+ error_values: vec![],
+ },
+ )
+ .unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let out = render_rst(&mut f, &mut sink);
+ assert!(out.contains("KAPI_TYPE_INT"));
+ assert!(out.contains("Returns 0 on success"));
+ assert!(out.contains("Return Value"));
+ }
+
+ #[test]
+ fn rst_context_flags() {
+ let mut f = RstFormatter::new();
+ let mut sink = Vec::new();
+
+ f.begin_document(&mut sink).unwrap();
+ f.begin_api_details(&mut sink, "sys_test").unwrap();
+ f.begin_context_flags(&mut sink).unwrap();
+ f.context_flag(&mut sink, "KAPI_CTX_PROCESS").unwrap();
+ f.context_flag(&mut sink, "KAPI_CTX_SLEEPABLE").unwrap();
+ f.end_context_flags(&mut sink).unwrap();
+ f.end_api_details(&mut sink).unwrap();
+
+ let out = render_rst(&mut f, &mut sink);
+ assert!(out.contains("KAPI_CTX_PROCESS"));
+ assert!(out.contains("KAPI_CTX_SLEEPABLE"));
+ assert!(out.contains("Execution Context"));
+ }
+}
diff --git a/tools/kapi/src/main.rs b/tools/kapi/src/main.rs
new file mode 100644
index 0000000000000..84d55686d73e0
--- /dev/null
+++ b/tools/kapi/src/main.rs
@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2026 Sasha Levin <sashal@kernel.org>
+
+//! kapi - Kernel API Specification Tool
+//!
+//! This tool extracts and displays kernel API specifications from multiple sources:
+//! - Kernel source code (KAPI macros)
+//! - Compiled vmlinux binaries (`.kapi_specs` ELF section)
+//! - Running kernel via debugfs
+
+use anyhow::Result;
+use clap::Parser;
+use std::io::{self, Write};
+
+mod extractor;
+mod formatter;
+
+use extractor::{ApiExtractor, DebugfsExtractor, SourceExtractor, VmlinuxExtractor};
+use formatter::{OutputFormat, create_formatter};
+
+#[derive(Parser, Debug)]
+#[command(author, version, about, long_about = None)]
+struct Args {
+ /// Path to the vmlinux file
+ #[arg(long, value_name = "PATH", group = "input")]
+ vmlinux: Option<String>,
+
+ /// Path to kernel source directory or file
+ #[arg(long, value_name = "PATH", group = "input")]
+ source: Option<String>,
+
+ /// Path to debugfs (defaults to /sys/kernel/debug if not specified)
+ #[arg(long, value_name = "PATH", group = "input")]
+ debugfs: Option<String>,
+
+ /// Optional: Name of specific API to show details for
+ api_name: Option<String>,
+
+ /// Output format
+ #[arg(long, short = 'f', default_value = "plain")]
+ format: String,
+}
+
+fn main() -> Result<()> {
+ let args = Args::parse();
+
+ let output_format: OutputFormat = args
+ .format
+ .parse()
+ .map_err(|e: String| anyhow::anyhow!(e))?;
+
+ let extractor: Box<dyn ApiExtractor> = match (&args.vmlinux, &args.source, &args.debugfs) {
+ (Some(vmlinux_path), None, None) => Box::new(VmlinuxExtractor::new(vmlinux_path)?),
+ (None, Some(source_path), None) => Box::new(SourceExtractor::new(source_path)?),
+ (None, None, Some(_) | None) => {
+ // If debugfs is specified or no input is provided, use debugfs
+ Box::new(DebugfsExtractor::new(args.debugfs.clone())?)
+ }
+ _ => {
+ anyhow::bail!("Please specify only one of --vmlinux, --source, or --debugfs")
+ }
+ };
+
+ display_apis(extractor.as_ref(), args.api_name, output_format)
+}
+
+fn display_apis(
+ extractor: &dyn ApiExtractor,
+ api_name: Option<String>,
+ output_format: OutputFormat,
+) -> Result<()> {
+ let mut formatter = create_formatter(output_format);
+ let mut stdout = io::stdout();
+
+ formatter.begin_document(&mut stdout)?;
+
+ if let Some(api_name_req) = api_name {
+ // Use the extractor to display API details
+ if let Some(_spec) = extractor.extract_by_name(&api_name_req)? {
+ extractor.display_api_details(&api_name_req, &mut *formatter, &mut stdout)?;
+ } else {
+ eprintln!("API '{}' not found.", api_name_req);
+ if output_format == OutputFormat::Plain {
+ writeln!(stdout, "\nAvailable APIs:")?;
+ for spec in extractor.extract_all()? {
+ writeln!(stdout, " {} ({})", spec.name, spec.api_type)?;
+ }
+ }
+ std::process::exit(1);
+ }
+ } else {
+ // Display list of APIs using the extractor
+ let all_specs = extractor.extract_all()?;
+
+ // Helper to display API list for a specific type
+ let mut display_api_type = |api_type: &str, title: &str| -> Result<()> {
+ let filtered: Vec<_> = all_specs.iter()
+ .filter(|s| s.api_type == api_type)
+ .collect();
+
+ if !filtered.is_empty() {
+ formatter.begin_api_list(&mut stdout, title)?;
+ for spec in filtered {
+ formatter.api_item(&mut stdout, &spec.name, &spec.api_type)?;
+ }
+ formatter.end_api_list(&mut stdout)?;
+ }
+ Ok(())
+ };
+
+ display_api_type("syscall", "System Calls")?;
+ display_api_type("ioctl", "IOCTLs")?;
+ display_api_type("function", "Functions")?;
+ display_api_type("sysfs", "Sysfs Attributes")?;
+
+ formatter.total_specs(&mut stdout, all_specs.len())?;
+ }
+
+ formatter.end_document(&mut stdout)?;
+
+ Ok(())
+}
--
2.51.0