[Mesa-dev] [PATCH 4/4] util: Get program name based on path when possible

[Nicolai Hähnle]

On 12.09.2018 14:31, Kazlauskas, Nicholas wrote:
> On 09/12/2018 12:26 AM, Timothy Arceri wrote:
>> On 12/9/18 2:24 am, Nicholas Kazlauskas wrote:
>>> Some programs start with the path and command line arguments in
>>> argv[0] (program_invocation_name). Chromium is an example of
>>> an application using mesa that does this.
>>
>> This change breaks the detection of Wine applications. Can you give an 
>> example of the string in program_invocation_name for Chromium? Can we 
>> not remove the arguments from the string?
> 
> The issue shows up with the subprocesses spawned by Chromium or Chome 
> where program_invocation_name shows up as something like this:
> 
> /usr/lib/chromium/chromium --type=gpu-process --field-trial-handle=...
> 
> The fix to this patch to avoid breaking Wine programs is probably just 
> deferring the realpath logic until the inner part of of the '/' path 
> detection.
> 
> I think this is the simplest method of dropping the arguments while 
> still retaining the exact program name match with strcmp.

Could we instead extend the syntax of the process filter? For example, 
understand a '*' wildcard at the end of the program name in the drirc 
XML do a prefix match instead of a full string match in that case.

Cheers,
Nicolai


> 
>>
>>>
>>> This tries to query the real path for the symbolic link /proc/self/exe
>>> to find the program name instead.
>>>
>>> Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas at amd.com>
>>> ---
>>>   src/util/u_process.c | 17 ++++++++++++++---
>>>   1 file changed, 14 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/src/util/u_process.c b/src/util/u_process.c
>>> index 5e5927678d..ca4d0770cb 100644
>>> --- a/src/util/u_process.c
>>> +++ b/src/util/u_process.c
>>> @@ -29,6 +29,7 @@
>>>   #include <string.h>
>>>   #include <errno.h>
>>>   #include <stdlib.h>
>>> +#include <stdio.h>
>>>   #undef GET_PROGRAM_NAME
>>> @@ -36,22 +37,32 @@
>>>   #    if !defined(__GLIBC__) || (__GLIBC__ < 2)
>>>   /* These aren't declared in any libc5 header */
>>>   extern char *program_invocation_name, *program_invocation_short_name;
>>> +extern char *__progname;
>>>   #    endif
>>>   static const char *
>>>   __getProgramName()
>>>   {
>>> -   char * arg = strrchr(program_invocation_name, '/');
>>> +   static char * actual_path;
>>> +   char * path = NULL;
>>> +   char * arg = NULL;
>>> +
>>> +   if (!actual_path)
>>> +      actual_path = realpath("/proc/self/exe", NULL);
>>> +
>>> +   path = actual_path ? actual_path : program_invocation_name;
>>> +
>>> +   arg = strrchr(path, '/');
>>>      if (arg)
>>>         return arg+1;
>>>      /* If there was no '/' at all we likely have a windows like path 
>>> from
>>>       * a wine application.
>>>       */
>>> -   arg = strrchr(program_invocation_name, '\\');
>>> +   arg = strrchr(path, '\\');
>>>      if (arg)
>>>         return arg+1;
>>> -   return program_invocation_name;
>>> +   return path;
>>>   }
>>>   #    define GET_PROGRAM_NAME() __getProgramName()
>>>   #elif defined(__CYGWIN__)
>>>
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> 
> Nicholas Kazlauskas