From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from issun5.hti.com ([130.210.202.3]) by issun6.hti.com (Netscape Messaging Server 3.6) with ESMTP id AAA5AAC for ; Mon, 30 Apr 2001 13:46:19 -0500 Message-ID: <3AEDB946.2060708@link.com> Date: Mon, 30 Apr 2001 15:13:10 -0400 From: "Richard F Weber" MIME-Version: 1.0 Subject: Re: Hopefully a simple question on /proc/pid/mem References: <3AEDAC29.40309@link.com> <20010430195007.F26638@redhat.com> Content-Type: multipart/alternative; boundary="------------020008010705030403010102" Sender: owner-linux-mm@kvack.org Return-Path: To: "Stephen C. Tweedie" Cc: linux-mm@kvack.org List-ID: --------------020008010705030403010102 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Well ptrace connects, but getting the data out is what seems to be the really tough part. I've seen some examples of opening up the /proc/pid/mem file just using the ................. int addr=0x; char buffer[255]; proc_file=open ("/proc/pid/mem",O_RDONLY); lseek(proc_file,addr,SEEK_SET); read (proc_file,buffer,sizeof(buffer)); ................. But then the system complains about "No Such Process". I know the process is working and this fails as both the user running the target process, as well as root. I'm also using a 2.2.16 kernel stock from RH7.0 (but I didn't think that would really matter). I don't need register access (at least not yet). The only other thing I'm wondering is if there is some permission that must be granted by the target process, but I've already tried the ptrace(PTRACE_TRACEME) line. Thanks. --Rich Stephen C. Tweedie wrote: >Hi, > >On Mon, Apr 30, 2001 at 02:17:13PM -0400, Richard F Weber wrote: > >>Hopefully this is a simple question. I'm trying to work on an external >>debugger that can bind to an external process, and open up memory >>locations on the heap to allow reading of data. >> >>Now I've tried using ptrace(), mmap() & lseek/read all with no success. >>The closest I've been able to get is to use ptrace() to do an attach to >>the target process, but couldn't read much of anything from it. >> > >ptrace is what other debuggers use. It really ought to work. > >Cheers, > Stephen >-- >To unsubscribe, send a message with 'unsubscribe linux-mm' in >the body to majordomo@kvack.org. For more info on Linux MM, >see: http://www.linux.eu.org/Linux-MM/ > --------------020008010705030403010102 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit Well ptrace connects, but getting the data out is what seems to be the really tough part. I've seen some examples of opening up the /proc/pid/mem file just using the

.................
int addr=0x<some memory address>;
char buffer[255];

proc_file=open ("/proc/pid/mem",O_RDONLY);
lseek(proc_file,addr,SEEK_SET);
read (proc_file,buffer,sizeof(buffer));
.................

But then the system complains about "No Such Process". I know the process is working and this fails as both the user running the target process, as well as root. I'm also using a 2.2.16 kernel stock from RH7.0 (but I didn't think that would really matter). I don't need register access (at least not yet).

The only other thing I'm wondering is if there is some permission that must be granted by the target process, but I've already tried the ptrace(PTRACE_TRACEME) line.

Thanks.

--Rich

Stephen C. Tweedie wrote:

Hi,

On Mon, Apr 30, 2001 at 02:17:13PM -0400, Richard F Weber wrote:

Hopefully this is a simple question.  I'm trying to work on an external 
debugger that can bind to an external process, and open up memory 
locations on the heap to allow reading of data.

Now I've tried using ptrace(), mmap() & lseek/read all with no success.  
The closest I've been able to get is to use ptrace() to do an attach to 
the target process, but couldn't read much of anything from it.


ptrace is what other debuggers use.  It really ought to work.

Cheers,
 Stephen
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux.eu.org/Linux-MM/

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