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

[Kazlauskas, Nicholas]

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.

> 
>>
>> 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