[Pidgin] #7902: The sighandler() function in pidgin/gtkmain.c doesn't restore a SIGALRM handler.

[Pidgin]

#7902: The sighandler() function in pidgin/gtkmain.c doesn't restore a SIGALRM
handler.
--------------------+-------------------------------------------------------
Reporter:  quonsto  |        Type:  defect                  
  Status:  new      |   Component:  pidgin (gtk)            
 Version:  2.5.3    |    Keywords:  pidgin SIGALRM gstreamer
--------------------+-------------------------------------------------------
 pidgin/gtkmain.c contains code, which looks like this:

 {{{
 #if defined(USE_GSTREAMER) && !defined(GST_CAN_DISABLE_FORKING)
 /* ... skipped long comment ... */
         case SIGCHLD:
                 /* Restore signal catching */
                 signal(SIGCHLD, sighandler);
                 alarm(1);
                 break;
         case SIGALRM:
 #else
         case SIGCHLD:
 #endif
                 clean_pid();
                 /* Restore signal catching */
                 signal(SIGCHLD, sighandler);
                 break;
 }}}

 If this code is compiled with macro USE_GSTREAMER defined and
 GST_CAN_DISABLE_FORKING not defined, it may lead to an uncatched SIGALRM
 (and pidgin termination), if the pidgin process receives more than one
 SIGCHLD during its lifetime.

 The problem is a SIGALRM handler which erroneously restores SIGCHLD
 handler instead of SIGALRM.

 The code after '#endif' in this piece of code is good for the case when
 being compiled without USE_GSTREAMER macro, or with
 GST_CAN_DISABLE_FORKING. [[BR]]
 But it doesn't suit otherwise.

 The proposed patch is to completely split the mentioned piece of code into
 two cases: one for "defined(USE_GSTREAMER) &&
 !defined(GST_CAN_DISABLE_FORKING)" and the other for the opposite case.

 A variant of the patch, implemeting this idea is given below:

 {{{

 --- gtkmain.c.orig      2008-12-21 03:38:16.000000000 +0300
 +++ gtkmain.c   2008-12-25 20:51:57.949286800 +0300
 @@ -207,13 +207,17 @@
                 alarm(1);
                 break;
         case SIGALRM:
 +               clean_pid();
 +               /* Restore signal catching */
 +               signal(SIGALRM, sighandler);
 +               break;
  #else
         case SIGCHLD:
 -#endif
                 clean_pid();
                 /* Restore signal catching */
                 signal(SIGCHLD, sighandler);
                 break;
 +#endif
         default:
                 purple_debug_warning("sighandler", "Caught signal %d\n",
 sig);
                 purple_core_quit();

 }}}


 Best regards, K.S.

-- 
Ticket URL: <http://developer.pidgin.im/ticket/7902>
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