[RFC v17][PATCH 49/60] c/r: save and restore sysvipc namespace basics

[Oren Laadan <orenl@librato.com>]

Add the helpers to checkpoint and restore the contents of 'struct
kern_ipc_perm'. Add header structures for ipc state. Put place-holders
to save and restore ipc state.

Save and restores the common state (parameters) of ipc namespace.

Generic code to iterate through the objects of sysvipc shared memory,
message queues and semaphores. The logic to save and restore the state
of these objects will be added in the next few patches.

Right now, we return -EPERM if the user calling sys_restart() isn't
allowed to create an object with the checkpointed uid.  We may prefer
to simply use the caller's uid in that case - but that could lead to
subtle userspace bugs?  Unsure, so going for the stricter behavior.

TODO: restore kern_ipc_perms->security.

Changelog[v17]:
  - Fix include: use checkpoint.h not checkpoint_hdr.h
  - Collect nsproxy->ipc_ns
  - Restore objects in the right namespace
  - If !CONFIG_IPC_NS only restore objects, not global settings
  - Don't overwrite global ipc-ns if !CONFIG_IPC_NS
  - Reset the checkpointed uid and gid info on ipc objects
  - Fix compilation with CONFIG_SYSVIPC=n
Changelog [Dan Smith <danms@us.ibm.com>]
  - Fix compilation with CONFIG_SYSVIPC=n
  - Update to match UTS changes

Signed-off-by: Oren Laadan <orenl@cs.columbia.edu>
---
 checkpoint/checkpoint.c          |    2 -
 checkpoint/objhash.c             |   28 ++++
 include/linux/checkpoint.h       |   13 ++
 include/linux/checkpoint_hdr.h   |   54 +++++++
 include/linux/checkpoint_types.h |    1 +
 init/Kconfig                     |    6 +
 ipc/Makefile                     |    2 +-
 ipc/checkpoint.c                 |  317 ++++++++++++++++++++++++++++++++++++++
 ipc/namespace.c                  |    2 +-
 ipc/util.h                       |   10 ++
 kernel/nsproxy.c                 |   22 ++-
 11 files changed, 449 insertions(+), 8 deletions(-)
 create mode 100644 ipc/checkpoint.c

diff --git a/checkpoint/checkpoint.c b/checkpoint/checkpoint.c
index 39ee917..e4f971e 100644
--- a/checkpoint/checkpoint.c
+++ b/checkpoint/checkpoint.c
@@ -331,8 +331,6 @@ static int may_checkpoint_task(struct ckpt_ctx *ctx, struct task_struct *t)
 
 	rcu_read_lock();
 	nsproxy = task_nsproxy(t);
-	if (nsproxy->ipc_ns != ctx->root_nsproxy->ipc_ns)
-		ret = -EPERM;
 	if (nsproxy->mnt_ns != ctx->root_nsproxy->mnt_ns)
 		ret = -EPERM;
 	if (nsproxy->pid_ns != ctx->root_nsproxy->pid_ns)
diff --git a/checkpoint/objhash.c b/checkpoint/objhash.c
index caa856c..29c7a04 100644
--- a/checkpoint/objhash.c
+++ b/checkpoint/objhash.c
@@ -15,6 +15,8 @@
 #include <linux/hash.h>
 #include <linux/file.h>
 #include <linux/fdtable.h>
+#include <linux/sched.h>
+#include <linux/ipc_namespace.h>
 #include <linux/checkpoint.h>
 #include <linux/checkpoint_hdr.h>
 
@@ -164,6 +166,22 @@ static int obj_uts_ns_users(void *ptr)
 	return atomic_read(&((struct uts_namespace *) ptr)->kref.refcount);
 }
 
+static int obj_ipc_ns_grab(void *ptr)
+{
+	get_ipc_ns((struct ipc_namespace *) ptr);
+	return 0;
+}
+
+static void obj_ipc_ns_drop(void *ptr)
+{
+	put_ipc_ns((struct ipc_namespace *) ptr);
+}
+
+static int obj_ipc_ns_users(void *ptr)
+{
+	return atomic_read(&((struct ipc_namespace *) ptr)->count);
+}
+
 static struct ckpt_obj_ops ckpt_obj_ops[] = {
 	/* ignored object */
 	{
@@ -231,6 +249,16 @@ static struct ckpt_obj_ops ckpt_obj_ops[] = {
 		.checkpoint = checkpoint_uts_ns,
 		.restore = restore_uts_ns,
 	},
+	/* ipc_ns object */
+	{
+		.obj_name = "IPC_NS",
+		.obj_type = CKPT_OBJ_IPC_NS,
+		.ref_drop = obj_ipc_ns_drop,
+		.ref_grab = obj_ipc_ns_grab,
+		.ref_users = obj_ipc_ns_users,
+		.checkpoint = checkpoint_ipc_ns,
+		.restore = restore_ipc_ns,
+	},
 };
 
 
diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
index 0085ea8..9d6b0cc 100644
--- a/include/linux/checkpoint.h
+++ b/include/linux/checkpoint.h
@@ -22,6 +22,9 @@
 #ifdef __KERNEL__
 #ifdef CONFIG_CHECKPOINT
 
+#include <linux/sched.h>
+#include <linux/nsproxy.h>
+#include <linux/ipc_namespace.h>
 #include <linux/checkpoint_types.h>
 #include <linux/checkpoint_hdr.h>
 
@@ -136,6 +139,15 @@ extern void *restore_ns(struct ckpt_ctx *ctx);
 extern int checkpoint_uts_ns(struct ckpt_ctx *ctx, void *ptr);
 extern void *restore_uts_ns(struct ckpt_ctx *ctx);
 
+/* ipc-ns */
+#ifdef CONFIG_SYSVIPC
+extern int checkpoint_ipc_ns(struct ckpt_ctx *ctx, void *ptr);
+extern void *restore_ipc_ns(struct ckpt_ctx *ctx);
+#else
+#define checkpoint_ipc_ns  checkpoint_bad
+#define restore_ipc_ns  restore_bad
+#endif /* CONFIG_SYSVIPC */
+
 /* file table */
 extern int ckpt_collect_file_table(struct ckpt_ctx *ctx, struct task_struct *t);
 extern int checkpoint_obj_file_table(struct ckpt_ctx *ctx,
@@ -204,6 +216,7 @@ extern int restore_memory_contents(struct ckpt_ctx *ctx, struct inode *inode);
 #define CKPT_DFILE	0x10		/* files and filesystem */
 #define CKPT_DMEM	0x20		/* memory state */
 #define CKPT_DPAGE	0x40		/* memory pages */
+#define CKPT_DIPC	0x80		/* sysvipc */
 
 #define CKPT_DDEFAULT	0xffff		/* default debug level */
 
diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h
index 18ab78f..3159750 100644
--- a/include/linux/checkpoint_hdr.h
+++ b/include/linux/checkpoint_hdr.h
@@ -59,6 +59,7 @@ enum {
 	CKPT_HDR_CPU,
 	CKPT_HDR_NS,
 	CKPT_HDR_UTS_NS,
+	CKPT_HDR_IPC_NS,
 
 	/* 201-299: reserved for arch-dependent */
 
@@ -73,6 +74,11 @@ enum {
 	CKPT_HDR_PGARR,
 	CKPT_HDR_MM_CONTEXT,
 
+	CKPT_HDR_IPC = 501,
+	CKPT_HDR_IPC_SHM,
+	CKPT_HDR_IPC_MSG,
+	CKPT_HDR_IPC_SEM,
+
 	CKPT_HDR_TAIL = 9001,
 
 	CKPT_HDR_ERROR = 9999,
@@ -99,6 +105,7 @@ enum obj_type {
 	CKPT_OBJ_MM,
 	CKPT_OBJ_NS,
 	CKPT_OBJ_UTS_NS,
+	CKPT_OBJ_IPC_NS,
 	CKPT_OBJ_MAX
 };
 
@@ -190,6 +197,7 @@ struct ckpt_hdr_task_ns {
 struct ckpt_hdr_ns {
 	struct ckpt_hdr h;
 	__s32 uts_objref;
+	__u32 ipc_objref;
 } __attribute__((aligned(8)));
 
 /* task's shared resources */
@@ -326,4 +334,50 @@ struct ckpt_hdr_pgarr {
 } __attribute__((aligned(8)));
 
 
+/* ipc commons */
+struct ckpt_hdr_ipcns {
+	struct ckpt_hdr h;
+	__u64 shm_ctlmax;
+	__u64 shm_ctlall;
+	__s32 shm_ctlmni;
+
+	__s32 msg_ctlmax;
+	__s32 msg_ctlmnb;
+	__s32 msg_ctlmni;
+
+	__s32 sem_ctl_msl;
+	__s32 sem_ctl_mns;
+	__s32 sem_ctl_opm;
+	__s32 sem_ctl_mni;
+} __attribute__((aligned(8)));
+
+struct ckpt_hdr_ipc {
+	struct ckpt_hdr h;
+	__u32 ipc_type;
+	__u32 ipc_count;
+} __attribute__((aligned(8)));
+
+struct ckpt_hdr_ipc_perms {
+	__s32 id;
+	__u32 key;
+	__u32 uid;
+	__u32 gid;
+	__u32 cuid;
+	__u32 cgid;
+	__u32 mode;
+	__u32 _padding;
+	__u64 seq;
+} __attribute__((aligned(8)));
+
+
+#define CKPT_TST_OVERFLOW_16(a, b) \
+	((sizeof(a) > sizeof(b)) && ((a) > SHORT_MAX))
+
+#define CKPT_TST_OVERFLOW_32(a, b) \
+	((sizeof(a) > sizeof(b)) && ((a) > INT_MAX))
+
+#define CKPT_TST_OVERFLOW_64(a, b) \
+	((sizeof(a) > sizeof(b)) && ((a) > LONG_MAX))
+
+
 #endif /* _CHECKPOINT_CKPT_HDR_H_ */
diff --git a/include/linux/checkpoint_types.h b/include/linux/checkpoint_types.h
index 0a9c58b..9ffa492 100644
--- a/include/linux/checkpoint_types.h
+++ b/include/linux/checkpoint_types.h
@@ -22,6 +22,7 @@
 
 struct ckpt_stats {
 	int uts_ns;
+	int ipc_ns;
 };
 
 struct ckpt_ctx {
diff --git a/init/Kconfig b/init/Kconfig
index a083161..21a7ca2 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -191,6 +191,12 @@ config SYSVIPC
 	  section 6.4 of the Linux Programmer's Guide, available from
 	  <http://www.tldp.org/guides.html>.
 
+config SYSVIPC_CHECKPOINT
+	bool
+	depends on SYSVIPC
+	depends on CHECKPOINT
+	default y
+
 config SYSVIPC_SYSCTL
 	bool
 	depends on SYSVIPC
diff --git a/ipc/Makefile b/ipc/Makefile
index 4e1955e..b747127 100644
--- a/ipc/Makefile
+++ b/ipc/Makefile
@@ -9,4 +9,4 @@ obj_mq-$(CONFIG_COMPAT) += compat_mq.o
 obj-$(CONFIG_POSIX_MQUEUE) += mqueue.o msgutil.o $(obj_mq-y)
 obj-$(CONFIG_IPC_NS) += namespace.o
 obj-$(CONFIG_POSIX_MQUEUE_SYSCTL) += mq_sysctl.o
-
+obj-$(CONFIG_SYSVIPC_CHECKPOINT) += checkpoint.o
diff --git a/ipc/checkpoint.c b/ipc/checkpoint.c
new file mode 100644
index 0000000..4eb1a97
--- /dev/null
+++ b/ipc/checkpoint.c
@@ -0,0 +1,317 @@
+/*
+ *  Checkpoint logic and helpers
+ *
+ *  Copyright (C) 2009 Oren Laadan
+ *
+ *  This file is subject to the terms and conditions of the GNU General Public
+ *  License.  See the file COPYING in the main directory of the Linux
+ *  distribution for more details.
+ */
+
+/* default debug level for output */
+#define CKPT_DFLAG  CKPT_DIPC
+
+#include <linux/ipc.h>
+#include <linux/msg.h>
+#include <linux/sched.h>
+#include <linux/ipc_namespace.h>
+#include <linux/checkpoint.h>
+#include <linux/checkpoint_hdr.h>
+
+#include "util.h"
+
+/* for ckpt_debug */
+static char *ipc_ind_to_str[] = { "sem", "msg", "shm" };
+
+#define shm_ids(ns)	((ns)->ids[IPC_SHM_IDS])
+#define msg_ids(ns)	((ns)->ids[IPC_MSG_IDS])
+#define sem_ids(ns)	((ns)->ids[IPC_SEM_IDS])
+
+/**************************************************************************
+ * Checkpoint
+ */
+
+int checkpoint_fill_ipc_perms(struct ckpt_hdr_ipc_perms *h,
+			      struct kern_ipc_perm *perm)
+{
+	if (ipcperms(perm, S_IROTH))
+		return -EACCES;
+
+	h->id = perm->id;
+	h->key = perm->key;
+	h->uid = perm->uid;
+	h->gid = perm->gid;
+	h->cuid = perm->cuid;
+	h->cgid = perm->cgid;
+	h->mode = perm->mode & S_IRWXUGO;
+	h->seq = perm->seq;
+
+	return 0;
+}
+
+static int checkpoint_ipc_any(struct ckpt_ctx *ctx,
+			      struct ipc_namespace *ipc_ns,
+			      int ipc_ind, int ipc_type,
+			      int (*func)(int id, void *p, void *data))
+{
+	struct ckpt_hdr_ipc *h;
+	struct ipc_ids *ipc_ids = &ipc_ns->ids[ipc_ind];
+	int ret = -ENOMEM;
+
+	down_read(&ipc_ids->rw_mutex);
+	h = ckpt_hdr_get_type(ctx, sizeof(*h), CKPT_HDR_IPC);
+	if (!h)
+		goto out;
+
+	h->ipc_type = ipc_type;
+	h->ipc_count = ipc_ids->in_use;
+	ckpt_debug("ipc-%s count %d\n", ipc_ind_to_str[ipc_ind], h->ipc_count);
+
+	ret = ckpt_write_obj(ctx, &h->h);
+	ckpt_hdr_put(ctx, h);
+	if (ret < 0)
+		goto out;
+
+	ret = idr_for_each(&ipc_ids->ipcs_idr, func, ctx);
+	ckpt_debug("ipc-%s ret %d\n", ipc_ind_to_str[ipc_ind], ret);
+ out:
+	up_read(&ipc_ids->rw_mutex);
+	return ret;
+}
+
+static int do_checkpoint_ipc_ns(struct ckpt_ctx *ctx,
+				struct ipc_namespace *ipc_ns)
+{
+	struct ckpt_hdr_ipcns *h;
+	int ret;
+
+	h = ckpt_hdr_get_type(ctx, sizeof(*h), CKPT_HDR_IPC_NS);
+	if (!h)
+		return -ENOMEM;
+
+	down_read(&shm_ids(ipc_ns).rw_mutex);
+	h->shm_ctlmax = ipc_ns->shm_ctlmax;
+	h->shm_ctlall = ipc_ns->shm_ctlall;
+	h->shm_ctlmni = ipc_ns->shm_ctlmni;
+	up_read(&shm_ids(ipc_ns).rw_mutex);
+
+	down_read(&msg_ids(ipc_ns).rw_mutex);
+	h->msg_ctlmax = ipc_ns->msg_ctlmax;
+	h->msg_ctlmnb = ipc_ns->msg_ctlmnb;
+	h->msg_ctlmni = ipc_ns->msg_ctlmni;
+	up_read(&msg_ids(ipc_ns).rw_mutex);
+
+	down_read(&sem_ids(ipc_ns).rw_mutex);
+	h->sem_ctl_msl = ipc_ns->sem_ctls[0];
+	h->sem_ctl_mns = ipc_ns->sem_ctls[1];
+	h->sem_ctl_opm = ipc_ns->sem_ctls[2];
+	h->sem_ctl_mni = ipc_ns->sem_ctls[3];
+	up_read(&sem_ids(ipc_ns).rw_mutex);
+
+	ret = ckpt_write_obj(ctx, &h->h);
+	ckpt_hdr_put(ctx, h);
+	if (ret < 0)
+		return ret;
+
+#if 0 /* NEXT FEW PATCHES */
+	ret = checkpoint_ipc_any(ctx, ipc_ns, IPC_SHM_IDS,
+				 CKPT_HDR_IPC_SHM, checkpoint_ipc_shm);
+	if (ret < 0)
+		return ret;
+	ret = checkpoint_ipc_any(ctx, ipc_ns, IPC_MSG_IDS,
+				 CKPT_HDR_IPC_MSG, checkpoint_ipc_msg);
+	if (ret < 0)
+		return ret;
+	ret = checkpoint_ipc_any(ctx, ipc_ns, IPC_SEM_IDS,
+				 CKPT_HDR_IPC_SEM, checkpoint_ipc_sem);
+#endif
+	return ret;
+}
+
+int checkpoint_ipc_ns(struct ckpt_ctx *ctx, void *ptr)
+{
+	return do_checkpoint_ipc_ns(ctx, (struct ipc_namespace *) ptr);
+}
+
+/**************************************************************************
+ * Restart
+ */
+
+/*
+ * check whether current task may create ipc object with
+ * checkpointed uids and gids.
+ * Return 1 if ok, 0 if not.
+ */
+static int validate_created_perms(struct ckpt_hdr_ipc_perms *h)
+{
+	const struct cred *cred = current_cred();
+	uid_t uid = cred->uid, euid = cred->euid;
+
+	/* actually I don't know - is CAP_IPC_OWNER the right one? */
+	if (((h->uid != uid && h->uid == euid) ||
+			(h->cuid != uid && h->cuid != euid) ||
+			!in_group_p(h->cgid) ||
+			!in_group_p(h->gid)) &&
+			!capable(CAP_IPC_OWNER))
+		return 0;
+	return 1;
+}
+
+int restore_load_ipc_perms(struct ckpt_hdr_ipc_perms *h,
+			   struct kern_ipc_perm *perm)
+{
+	if (h->id < 0)
+		return -EINVAL;
+	if (CKPT_TST_OVERFLOW_16(h->uid, perm->uid) ||
+	    CKPT_TST_OVERFLOW_16(h->gid, perm->gid) ||
+	    CKPT_TST_OVERFLOW_16(h->cuid, perm->cuid) ||
+	    CKPT_TST_OVERFLOW_16(h->cgid, perm->cgid) ||
+	    CKPT_TST_OVERFLOW_16(h->mode, perm->mode))
+		return -EINVAL;
+	if (h->seq >= USHORT_MAX)
+		return -EINVAL;
+	if (h->mode & ~S_IRWXUGO)
+		return -EINVAL;
+
+	/* FIX: verify the ->mode field makes sense */
+
+	perm->id = h->id;
+	perm->key = h->key;
+
+	if (!validate_created_perms(h))
+		return -EPERM;
+	perm->uid = h->uid;
+	perm->gid = h->gid;
+	perm->cuid = h->cuid;
+	perm->cgid = h->cgid;
+	perm->mode = h->mode;
+	perm->seq = h->seq;
+	/*
+	 * Todo: restore perm->security.
+	 * At the moment it gets set by security_x_alloc() called through
+	 * ipcget()->ipcget_public()->ops-.getnew (->nequeue for instance)
+	 * We will want to ask the LSM to consider resetting the
+	 * checkpointed ->security, based on current_security(),
+	 * the checkpointed ->security, and the checkpoint file context.
+	 */
+
+	return 0;
+}
+
+static int restore_ipc_any(struct ckpt_ctx *ctx, struct ipc_namespace *ipc_ns,
+			   int ipc_ind, int ipc_type,
+			   int (*func)(struct ckpt_ctx *ctx,
+				       struct ipc_namespace *ns))
+{
+	struct ckpt_hdr_ipc *h;
+	int n, ret;
+
+	h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_IPC);
+	if (IS_ERR(h))
+		return PTR_ERR(h);
+
+	ckpt_debug("ipc-%s: count %d\n", ipc_ind_to_str[ipc_ind], h->ipc_count);
+
+	ret = -EINVAL;
+	if (h->ipc_type != ipc_type)
+		goto out;
+
+	ret = 0;
+	for (n = 0; n < h->ipc_count; n++) {
+		ret = (*func)(ctx, ipc_ns);
+		if (ret < 0)
+			goto out;
+	}
+ out:
+	ckpt_debug("ipc-%s: ret %d\n", ipc_ind_to_str[ipc_ind], ret);
+	ckpt_hdr_put(ctx, h);
+	return ret;
+}
+
+static struct ipc_namespace *do_restore_ipc_ns(struct ckpt_ctx *ctx)
+{
+	struct ipc_namespace *ipc_ns = NULL;
+	struct ckpt_hdr_ipcns *h;
+	int ret;
+
+	h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_IPC_NS);
+	if (IS_ERR(h))
+		return ERR_PTR(PTR_ERR(h));
+
+	ret = -EINVAL;
+	if (h->shm_ctlmax < 0 || h->shm_ctlall < 0 || h->shm_ctlmni < 0)
+		goto out;
+	if (h->msg_ctlmax < 0 || h->msg_ctlmnb < 0 || h->msg_ctlmni < 0)
+		goto out;
+	if (h->sem_ctl_msl < 0 || h->sem_ctl_mns < 0 ||
+	    h->sem_ctl_opm < 0 || h->sem_ctl_mni < 0)
+		goto out;
+
+	/*
+	 * If !CONFIG_IPC_NS, do not restore the global IPC state, as
+	 * it is used by other processes. It is ok to try to restore
+	 * the {shm,msg,sem} objects: in the worst case the requested
+	 * identifiers will be in use.
+	 */
+#ifdef CONFIG_IPC_NS
+	ret = -ENOMEM;
+	ipc_ns = create_ipc_ns();
+	if (!ipc_ns)
+		goto out;
+
+	down_read(&shm_ids(ipc_ns).rw_mutex);
+	ipc_ns->shm_ctlmax = h->shm_ctlmax;
+	ipc_ns->shm_ctlall = h->shm_ctlall;
+	ipc_ns->shm_ctlmni = h->shm_ctlmni;
+	up_read(&shm_ids(ipc_ns).rw_mutex);
+
+	down_read(&msg_ids(ipc_ns).rw_mutex);
+	ipc_ns->msg_ctlmax = h->msg_ctlmax;
+	ipc_ns->msg_ctlmnb = h->msg_ctlmnb;
+	ipc_ns->msg_ctlmni = h->msg_ctlmni;
+	up_read(&msg_ids(ipc_ns).rw_mutex);
+
+	down_read(&sem_ids(ipc_ns).rw_mutex);
+	ipc_ns->sem_ctls[0] = h->sem_ctl_msl;
+	ipc_ns->sem_ctls[1] = h->sem_ctl_mns;
+	ipc_ns->sem_ctls[2] = h->sem_ctl_opm;
+	ipc_ns->sem_ctls[3] = h->sem_ctl_mni;
+	up_read(&sem_ids(ipc_ns).rw_mutex);
+#else
+	ret = -EEXIST;
+	/* complain if image contains multiple namespaces */
+	if (ctx->stats.ipc_ns)
+		goto out;
+	ipc_ns = current->nsproxy->ipc_ns;
+	get_ipc_ns(ipc_ns);
+#endif
+
+#if 0 /* NEXT FEW PATCHES */
+	ret = restore_ipc_any(ctx, ipc_ns, IPC_SHM_IDS,
+			      CKPT_HDR_IPC_SHM, restore_ipc_shm);
+	if (ret < 0)
+		goto out;
+	ret = restore_ipc_any(ctx, ipc_ns, IPC_MSG_IDS,
+			      CKPT_HDR_IPC_MSG, restore_ipc_msg);
+	if (ret < 0)
+		goto out;
+	ret = restore_ipc_any(ctx, ipc_ns, IPC_SEM_IDS,
+			      CKPT_HDR_IPC_SEM, restore_ipc_sem);
+#endif
+	if (ret < 0)
+		goto out;
+
+	ctx->stats.ipc_ns++;
+ out:
+	ckpt_hdr_put(ctx, h);
+	if (ret < 0) {
+		put_ipc_ns(ipc_ns);
+		ipc_ns = ERR_PTR(ret);
+	}
+	return ipc_ns;
+}
+
+void *restore_ipc_ns(struct ckpt_ctx *ctx)
+{
+	return (void *) do_restore_ipc_ns(ctx);
+}
diff --git a/ipc/namespace.c b/ipc/namespace.c
index a1094ff..8e5ea32 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -14,7 +14,7 @@
 
 #include "util.h"
 
-static struct ipc_namespace *create_ipc_ns(void)
+struct ipc_namespace *create_ipc_ns(void)
 {
 	struct ipc_namespace *ns;
 	int err;
diff --git a/ipc/util.h b/ipc/util.h
index 159a73c..8ae1f8e 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -12,6 +12,7 @@
 
 #include <linux/unistd.h>
 #include <linux/err.h>
+#include <linux/checkpoint.h>
 
 #define SEQ_MULTIPLIER	(IPCMNI)
 
@@ -175,4 +176,13 @@ int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
 void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
 	       void (*free)(struct ipc_namespace *, struct kern_ipc_perm *));
 
+struct ipc_namespace *create_ipc_ns(void);
+
+#ifdef CONFIG_CHECKPOINT
+extern int checkpoint_fill_ipc_perms(struct ckpt_hdr_ipc_perms *h,
+				     struct kern_ipc_perm *perm);
+extern int restore_load_ipc_perms(struct ckpt_hdr_ipc_perms *h,
+				  struct kern_ipc_perm *perm);
+#endif
+
 #endif
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 4f48a68..fddc724 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -248,6 +248,7 @@ int ckpt_collect_ns(struct ckpt_ctx *ctx, struct task_struct *t)
 	ret = ckpt_obj_collect(ctx, nsproxy->uts_ns, CKPT_OBJ_UTS_NS);
 	if (ret < 0)
 		goto out;
+	ret = ckpt_obj_collect(ctx, nsproxy->ipc_ns, CKPT_OBJ_IPC_NS);
 
 	/* TODO: collect other namespaces here */
  out:
@@ -268,6 +269,11 @@ static int do_checkpoint_ns(struct ckpt_ctx *ctx, struct nsproxy *nsproxy)
 	if (ret <= 0)
 		goto out;
 	h->uts_objref = ret;
+	ret = checkpoint_obj(ctx, nsproxy->ipc_ns, CKPT_OBJ_IPC_NS);
+	if (ret < 0)
+		goto out;
+	h->ipc_objref = ret;
+
 	/* TODO: Write other namespaces here */
 
 	ret = ckpt_write_obj(ctx, &h->h);
@@ -287,6 +293,7 @@ static struct nsproxy *do_restore_ns(struct ckpt_ctx *ctx)
 	struct ckpt_hdr_ns *h;
 	struct nsproxy *nsproxy = NULL;
 	struct uts_namespace *uts_ns;
+	struct ipc_namespace *ipc_ns;
 	int ret;
 
 	h = ckpt_read_obj_type(ctx, sizeof(*h), CKPT_HDR_NS);
@@ -294,7 +301,8 @@ static struct nsproxy *do_restore_ns(struct ckpt_ctx *ctx)
 		return (struct nsproxy *) h;
 
 	ret = -EINVAL;
-	if (h->uts_objref <= 0)
+	if (h->uts_objref <= 0 ||
+	    h->ipc_objref <= 0)
 		goto out;
 
 	uts_ns = ckpt_obj_fetch(ctx, h->uts_objref, CKPT_OBJ_UTS_NS);
@@ -302,8 +310,13 @@ static struct nsproxy *do_restore_ns(struct ckpt_ctx *ctx)
 		ret = PTR_ERR(uts_ns);
 		goto out;
 	}
+	ipc_ns = ckpt_obj_fetch(ctx, h->ipc_objref, CKPT_OBJ_IPC_NS);
+	if (IS_ERR(ipc_ns)) {
+		ret = PTR_ERR(ipc_ns);
+		goto out;
+	}
 
-#if defined(COFNIG_UTS_NS)
+#if defined(COFNIG_UTS_NS) || defined(CONFIG_IPC_NS)
 	ret = -ENOMEM;
 	nsproxy = create_nsproxy();
 	if (!nsproxy)
@@ -311,9 +324,9 @@ static struct nsproxy *do_restore_ns(struct ckpt_ctx *ctx)
 
 	get_uts_ns(uts_ns);
 	nsproxy->uts_ns = uts_ns;
-
-	get_ipc_ns(current->nsproxy->ipc_ns);
+	get_ipc_ns(ipc_ns);
 	nsproxy->ipc_ns = ipc_ns;
+
 	get_pid_ns(current->nsproxy->pid_ns);
 	nsproxy->pid_ns = current->nsproxy->pid_ns;
 	get_mnt_ns(current->nsproxy->mnt_ns);
@@ -325,6 +338,7 @@ static struct nsproxy *do_restore_ns(struct ckpt_ctx *ctx)
 	get_nsproxy(nsproxy);
 
 	BUG_ON(nsproxy->uts_ns != uts_ns);
+	BUG_ON(nsproxy->ipc_ns != ipc_ns);
 #endif
 
 	/* TODO: add more namespaces here */
-- 
1.6.0.4

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