[Emacs-diffs] trunk r113138: Clean up SIGCHLD handling a bit.

[Paul Eggert]

------------------------------------------------------------
revno: 113138
revision-id: address@hidden
parent: address@hidden
fixes bug: http://debbugs.gnu.org/14569
committer: Paul Eggert <address@hidden>
branch nick: trunk
timestamp: Sat 2013-06-22 12:01:47 -0700
message:
  Clean up SIGCHLD handling a bit.
  
  * process.c, process.h (catch_child_signal):
  Now always extern, even if !NS_IMPL_GNUSTEP.
  * process.c (catch_child_signal): Move glib tickler here from
  init_process_emacs, so that it's done earlier in Emacs
  initialization.  Also move the noninteractive && !initialized
  check here from init_process_emacs.  This is all a bit cleaner for
  GNUish platforms, and I hope it works around the Cygwin bug.
  * sysdep.c (init_signals): Invoke catch_child_signal here, so
  that glib signal handling is tickled before glib creates threads.
modified:
  src/ChangeLog                  changelog-20091113204419-o5vbwnq5f7feedwu-1438
  src/process.c                  process.c-20091113204419-o5vbwnq5f7feedwu-462
  src/process.h                  process.h-20091113204419-o5vbwnq5f7feedwu-272
  src/sysdep.c                   sysdep.c-20091113204419-o5vbwnq5f7feedwu-448

=== modified file 'src/ChangeLog'
--- a/src/ChangeLog     2013-06-22 16:43:39 +0000
+++ b/src/ChangeLog     2013-06-22 19:01:47 +0000
@@ -1,5 +1,16 @@
 2013-06-22  Paul Eggert  <address@hidden>
 
+       Clean up SIGCHLD handling a bit (Bug#14569).
+       * process.c, process.h (catch_child_signal):
+       Now always extern, even if !NS_IMPL_GNUSTEP.
+       * process.c (catch_child_signal): Move glib tickler here from
+       init_process_emacs, so that it's done earlier in Emacs
+       initialization.  Also move the noninteractive && !initialized
+       check here from init_process_emacs.  This is all a bit cleaner for
+       GNUish platforms, and I hope it works around the Cygwin bug.
+       * sysdep.c (init_signals): Invoke catch_child_signal here, so
+       that glib signal handling is tickled before glib creates threads.
+
        * process.c (wait_reading_process_output): Avoid int overflow
        when reading more than 2 GiB total from a process.
 

=== modified file 'src/process.c'
--- a/src/process.c     2013-06-22 16:43:39 +0000
+++ b/src/process.c     2013-06-22 19:01:47 +0000
@@ -7060,13 +7060,29 @@
   return system_process_attributes (pid);
 }
 
-#ifndef NS_IMPL_GNUSTEP
-static
-#endif
+/* Arrange to catch SIGCHLD if needed.  */
+
 void
 catch_child_signal (void)
 {
   struct sigaction action, old_action;
+
+#if !defined CANNOT_DUMP
+  if (noninteractive && !initialized)
+    return;
+#endif
+
+#if defined HAVE_GLIB && !defined WINDOWSNT
+  /* Tickle glib's child-handling code.  Ask glib to wait for Emacs itself;
+     this should always fail, but is enough to initialize glib's
+     private SIGCHLD handler, allowing the code below to copy it into
+     LIB_CHILD_HANDLER.
+
+     Do this early in Emacs initialization, before glib creates
+     threads, to avoid race condition bugs in Cygwin glib.  */
+  g_source_unref (g_child_watch_source_new (getpid ()));
+#endif
+
   emacs_sigaction_init (&action, deliver_child_signal);
   sigaction (SIGCHLD, &action, &old_action);
   eassert (! (old_action.sa_flags & SA_SIGINFO));
@@ -7086,19 +7102,6 @@
 
   inhibit_sentinels = 0;
 
-#ifndef CANNOT_DUMP
-  if (! noninteractive || initialized)
-#endif
-    {
-#if defined HAVE_GLIB && !defined WINDOWSNT
-      /* Tickle glib's child-handling code.  Ask glib to wait for Emacs itself;
-        this should always fail, but is enough to initialize glib's
-        private SIGCHLD handler.  */
-      g_source_unref (g_child_watch_source_new (getpid ()));
-#endif
-      catch_child_signal ();
-    }
-
   FD_ZERO (&input_wait_mask);
   FD_ZERO (&non_keyboard_wait_mask);
   FD_ZERO (&non_process_wait_mask);

=== modified file 'src/process.h'
--- a/src/process.h     2013-06-03 18:29:30 +0000
+++ b/src/process.h     2013-06-22 19:01:47 +0000
@@ -217,8 +217,6 @@
 extern void delete_read_fd (int fd);
 extern void add_write_fd (int fd, fd_callback func, void *data);
 extern void delete_write_fd (int fd);
-#ifdef NS_IMPL_GNUSTEP
 extern void catch_child_signal (void);
-#endif
 
 INLINE_HEADER_END

=== modified file 'src/sysdep.c'
--- a/src/sysdep.c      2013-03-24 12:59:45 +0000
+++ b/src/sysdep.c      2013-06-22 19:01:47 +0000
@@ -1901,6 +1901,8 @@
       sigaction (SIGFPE, &action, 0);
     }
 
+  catch_child_signal ();
+
 #ifdef SIGUSR1
   add_user_signal (SIGUSR1, "sigusr1");
 #endif