Do not tickle glib SIGCHLD handling if Cygwin.

This mostly consists of undoing recent changes.
* callproc.c (Fcall_process):
* process.c (create_process):
Do not worry about catching SIGCHLD here, undoing previous change.
* nsterm.m (ns_term_init): Re-catch SIGCHLD, undoing previous change.
* process.c, process.h (catch_child_signal):
No longer extern if !NS_IMPL_GNUSTEP, undoing 06-22 change.
* process.c (catch_child_handler): Don't worry about being called
lazily and do not assume caller has blocked SIGCHLD, undoing
previous change.  Move first-time stuff back to
init_process_emacs, undoing 06-22 change.  If CYGWIN, do not
tickle glib, as that causes Cygwin bootstrap to fail.  Do not
set lib_child_handler if it's already initialized, which may
help avoid problems on GNUStep.

5 files changed, 54 insertions, 36 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 6357491725d..837d946a26e 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,21 @@
+2013-06-27  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Do not tickle glib SIGCHLD handling if Cygwin (Bug#14569).
+        This mostly consists of undoing recent changes.
+        * callproc.c (Fcall_process):
+        * process.c (create_process):
+        Do not worry about catching SIGCHLD here, undoing previous change.
+        * nsterm.m (ns_term_init): Re-catch SIGCHLD, undoing previous change.
+        * process.c, process.h (catch_child_signal):
+        No longer extern if !NS_IMPL_GNUSTEP, undoing 06-22 change.
+        * process.c (catch_child_handler): Don't worry about being called
+        lazily and do not assume caller has blocked SIGCHLD, undoing
+        previous change.  Move first-time stuff back to
+        init_process_emacs, undoing 06-22 change.  If CYGWIN, do not
+        tickle glib, as that causes Cygwin bootstrap to fail.  Do not
+        set lib_child_handler if it's already initialized, which may
+        help avoid problems on GNUStep.
+
 2013-06-23  Paul Eggert  <eggert@cs.ucla.edu>
 
         A more-conservative workaround for Cygwin SIGCHLD issues (Bug#14569).
diff --git a/src/callproc.c b/src/callproc.c
index 7db984fa71c..f0aa8222342 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -613,7 +613,6 @@ usage: (call-process PROGRAM &optional INFILE DESTINATION DISPLAY &rest ARGS)  *
 
     block_input ();
     block_child_signal ();
-    catch_child_signal ();
 
 #ifdef WINDOWSNT
     pid = child_setup (filefd, fd1, fd_error, new_argv, 0, current_dir);
diff --git a/src/nsterm.m b/src/nsterm.m
index c88e5034d39..93f693fe55e 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -4360,6 +4360,12 @@ ns_term_init (Lisp_Object display_name)
 
   [NSApp run];
   ns_do_open_file = YES;
+
+#ifdef NS_IMPL_GNUSTEP
+  /* GNUstep steals SIGCHLD for use in NSTask, but we don't use NSTask.
+     We must re-catch it so subprocess works.  */
+  catch_child_signal ();
+#endif
   return dpyinfo;
 }
 
diff --git a/src/process.c b/src/process.c
index 3f062b6db16..b63a985fcec 100644
--- a/src/process.c
+++ b/src/process.c
@@ -1685,7 +1685,6 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
 
   block_input ();
   block_child_signal ();
-  catch_child_signal ();
 
 #ifndef WINDOWSNT
   /* vfork, and prevent local vars from being clobbered by the vfork.  */
@@ -7061,48 +7060,24 @@ integer or floating point values.
    futz with the SIGCHLD handler, but before Emacs forks any children.
    This function's caller should block SIGCHLD.  */
 
+#ifndef NS_IMPL_GNUSTEP
+static
+#endif
 void
 catch_child_signal (void)
 {
   struct sigaction action, old_action;
-
-#if !defined CANNOT_DUMP
-  if (noninteractive && !initialized)
-    return;
-#endif
-
-#ifndef NS_IMPL_GNUSTEP
-  if (lib_child_handler)
-    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 here, rather than early in Emacs initialization where it
-     might make more sense, to try to avoid bugs in Cygwin glib (Bug#14569).  */
-  {
-    GSource *source = g_child_watch_source_new (getpid ());
-    g_source_unref (source);
-  }
-#endif
-
   emacs_sigaction_init (&action, deliver_child_signal);
+  block_child_signal ();
   sigaction (SIGCHLD, &action, &old_action);
   eassert (! (old_action.sa_flags & SA_SIGINFO));
 
-#ifdef NS_IMPL_GNUSTEP
-  if (old_action.sa_handler == deliver_child_signal)
-    return;
-#endif
-
-  lib_child_handler
-    = (old_action.sa_handler == SIG_DFL || old_action.sa_handler == SIG_IGN
-       ? dummy_handler
-       : old_action.sa_handler);
+  if (old_action.sa_handler != deliver_child_signal)
+    lib_child_handler
+      = (old_action.sa_handler == SIG_DFL || old_action.sa_handler == SIG_IGN
+         ? dummy_handler
+         : old_action.sa_handler);
+  unblock_child_signal ();
 }
 
 
@@ -7116,6 +7091,24 @@ init_process_emacs (void)
 
   inhibit_sentinels = 0;
 
+#ifndef CANNOT_DUMP
+  if (! noninteractive || initialized)
+#endif
+    {
+#if defined HAVE_GLIB && !defined WINDOWSNT && !defined CYGWIN
+      /* 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.
+
+         For some reason tickling causes Cygwin bootstrap to fail, so it's
+         skipped under Cygwin.  FIXME: Skipping the tickling likely causes
+         bugs in subprocess handling under Cygwin (Bug#14569).  */
+      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);
diff --git a/src/process.h b/src/process.h
index 3f86e5f3945..e7ee5f9adde 100644
--- a/src/process.h
+++ b/src/process.h
@@ -219,6 +219,8 @@ extern void add_read_fd (int fd, fd_callback func, void *data);
 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