Fix crash when using Emacs as commit editor for git.

* callproc.c (setpgrp): Remove macro, as we now use setpgid
and it is configured in conf_post.h.
(Fcall_process): Don't invoke both setsid and setpgid; the former
is enough, if it exists.
* callproc.c (Fcall_process, child_setup):
* process.c (create_process): Use setpgid.
* conf_post.h (setpgid) [!HAVE_SETPGID]: New macro, which substitutes
for the real thing.
* dispnew.c (init_display): Initialize the foreground group
if we are running a tty display.
* emacs.c (main): Do not worry about setpgrp; init_display does it now.
* lisp.h (init_foreground_group): New decl.
* sysdep.c (inherited_pgroup): New static var.
(init_foreground_group, tcsetpgrp_without_stopping)
(narrow_foreground_group, widen_foreground_group): New functions.
(init_sys_modes): Narrow foreground group.
(reset_sys_modes): Widen foreground group.

Fixes: debbugs:12697

1 files changed, 5 insertions, 18 deletions

diff --git a/src/callproc.c b/src/callproc.c
index b33882e54c2..c236f22fc86 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -64,13 +64,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include "nsterm.h"
 #endif
 
-#ifdef HAVE_SETPGID
-#if !defined (USG)
-#undef setpgrp
-#define setpgrp setpgid
-#endif
-#endif
-
 /* Pattern used by call-process-region to make temp files.  */
 static Lisp_Object Vtemp_file_name_pattern;
 
@@ -618,14 +611,12 @@ usage: (call-process PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS)  */)
       {
         if (fd[0] >= 0)
           emacs_close (fd[0]);
+
 #ifdef HAVE_SETSID
         setsid ();
-#endif
-#if defined (USG)
-        setpgrp ();
 #else
-        setpgrp (pid, pid);
-#endif /* USG */
+        setpgid (0, 0);
+#endif
 
         /* Emacs ignores SIGPIPE, but the child should not.  */
         signal (SIGPIPE, SIG_DFL);
@@ -1295,13 +1286,9 @@ child_setup (int in, int out, int err, char **new_argv, bool set_pgrp,
   if (err != in && err != out)
     emacs_close (err);
 
-#if defined (USG)
-#ifndef SETPGRP_RELEASES_CTTY
-  setpgrp ();                   /* No arguments but equivalent in this case */
+#if defined HAVE_SETPGID || ! (defined USG && defined SETPGRP_RELEASES_CTTY)
+  setpgid (pid, pid);
 #endif
-#else /* not USG */
-  setpgrp (pid, pid);
-#endif /* not USG */
 
   /* setpgrp_of_tty is incorrect here; it uses input_fd.  */
   tcsetpgrp (0, pid);