Re: Intercepting system calls

From: Maxin B John
Date: Fri Dec 23 2011 - 07:29:10 EST


Hi,

On Fri, Dec 23, 2011 at 1:59 PM, Gaurav Saxena <grvsaxena419@xxxxxxxxx> wrote:
> I found that Ubuntu does not have a kprobe enabled kernel. :( I don't
> think I could use kprobes then.

Probably you can find a solution using Systemtap.

Have a look at this example:
http://sourceware.org/systemtap/examples/general/badname.stp

It just needs some modifications to meet your needs.

HTH,
Maxin B. John

> On Fri, Dec 23, 2011 at 3:20 PM, Gaurav Saxena <grvsaxena419@xxxxxxxxx> wrote:
>> Hello Jiri
>>
>> On Fri, Dec 23, 2011 at 3:17 PM, Jiri Kosina <jkosina@xxxxxxx> wrote:
>>> On Thu, 22 Dec 2011, Gaurav Saxena wrote:
>>>
>>>> I am writing an application for which I need to intercept some
>>>> filesystem system calls eg. unlink. I need unlink to call my code
>>>> before deleting abc so that I could probably prevent unlink . I would
>>>> like to implement this in a kernel module instead of modifying kernel
>>>> code itself. I would like to intercept system calls by replacing
>>>> system calls but I have not been able to find any method of doing that
>>>> in linux > 3.0. Please suggest some method of doing that.
>>>
>>> Write a kernel module that instruments sys_unlink() via krpobes. See
>>> Documentation/kprobes.txt for details.
>> Ok. I am looking at its details, will try that. But how could a probe
>> prevent execution of a system call?
>>>
>>> --
>>> Jiri Kosina
>>> SUSE Labs
>>>
>>
>>
>>
>> --
>> Thanks and Regards ,
>> Gaurav
>
>
>
> --
> Thanks and Regards ,
> Gaurav
> --
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