Re: [Qemu-devel] [PATCH] linux-user: add option to intercept execve() syscalls

[Laurent Vivier <laurent@vivier.eu>]

Le 22/01/2016 11:47, Peter Maydell a écrit :
> On 22 January 2016 at 10:33, Laurent Vivier <laurent@vivier.eu> wrote:
>> Le 22/01/2016 11:01, Petros Angelatos a écrit :
>>> This was my initial approach too, but argv[0] can be just the filename
>>> like "qemu-arm-static". And while I could add extra logic to look this
>>> up in the PATH, someone could run it from a completely different
>>> location. Then I looked for a way to get the path of the current
>>> executable but every platform has its own way of doing that and I
>>> didn't want to add all these cases.
>>>
>>> https://stackoverflow.com/questions/1023306/finding-current-executables-path-without-proc-self-exe
>>
>> linux-user works only on linux.
>> qemu uses glib-2.0, so you can use g_find_program_in_path().
> 
> If QEMU was started via execle() to set the environment of the
> executed process and that specified environment has a different
> PATH, then g_find_program_in_path() will give the wrong answer.
> Using AT_EXECFN (perhaps with a fallback to /proc/self/exe) seems
> like a better approach to me.

I agree, you can use getauxval(AT_EXECFN).

>>> questions. Is it ok that I deleted part of the patch for my reply to
>>> code review, or should I have replied inline without deleting
>>
>> Generally, it's better to not delete parts. So, someone tacking the mail
>> thread at a moment can read the whole history in the last mail.
> 
> I tend to happily delete parts and assume that readers have
> access to the thread (via the archive or in their mail readers).
> Not deleting bits makes it hard to read replies if there's
> a conversation about a small part of a large patch.

Yes, I do that also... :)

Laurent