Handle errno and exit status a bit more carefully.

* lib/ignore-value.h: Remove this gnulib-imported file.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* admin/merge-gnulib (GNULIB_MODULES): Remove ignore-value.
* src/callproc.c (child_setup) [!DOS_NT]: Don't try to stuff an error
number into an exit status.  Instead, use EXIT_CANCELED.
(child_setup) [!MSDOS]: Avoid possible deadlock with vfork.
* src/callproc.c (relocate_fd):
* src/emacs.c (close_output_streams, main):
* src/process.c (create_process):
* src/sysdep.c (sys_subshell) [!DOS_NT || !WINDOWSNT]:
Use emacs_perror for simplicity.
* src/callproc.c (relocate_fd, main):
* src/sysdep.c (sys_subshell):
Exit with EXIT_CANCELED etc., not 1, when exec setup fails.
(shut_down_emacs): Use emacs_write, not write.
* src/emacs.c, src/sysdep.c: Don't include <ignore-value.h>.
* src/fileio.c (Fcopy_file, e_write):
* src/nsterm.m (ns_select):
* src/process.c (send_process):
* src/sound.c (vox_write):
Use emacs_write_sig, not emacs_write.
* src/lisp.h (emacs_write_sig, emacs_perror): New decls.
* src/process.h (EXIT_CANCELED), EXIT_CANNOT_INVOKE, EXIT_ENOENT):
New constants.
* src/sysdep.c (emacs_backtrace): Use emacs_write, not ignore_value
of write.
(emacs_full_write): New function.
(emacs_write): Rewrite to use it.
(emacswrite_sig, emacs_perror): New functions.
* src/xrdb.c (fatal): Don't invoke perror, since errno might be garbage.

1 files changed, 9 insertions, 12 deletions

diff --git a/src/callproc.c b/src/callproc.c
index 369d6eda909..fc274f3d9c0 100644
--- a/src/callproc.c
+++ b/src/callproc.c
@@ -1221,7 +1221,7 @@ child_setup (int in, int out, int err, char **new_argv, bool set_pgrp,
        are changed between the check and this chdir, but we should
        at least check.  */
     if (chdir (temp) < 0)
-      _exit (errno);
+      _exit (EXIT_CANCELED);
 #else /* DOS_NT */
     /* Get past the drive letter, so that d:/ is left alone.  */
     if (i > 2 && IS_DEVICE_SEP (temp[1]) && IS_DIRECTORY_SEP (temp[2]))
@@ -1366,10 +1366,12 @@ child_setup (int in, int out, int err, char **new_argv, bool set_pgrp,
 
   execve (new_argv[0], new_argv, env);
 
-  emacs_write (1, "Can't exec program: ", 20);
-  emacs_write (1, new_argv[0], strlen (new_argv[0]));
-  emacs_write (1, "\n", 1);
-  _exit (1);
+  /* Don't output the program name here, as it can be arbitrarily long,
+     and a long write from a vforked child to its parent can cause a
+     deadlock.  */
+  emacs_perror ("child process");
+
+  _exit (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE);
 
 #else /* MSDOS */
   pid = run_msdos_command (new_argv, pwd_var + 4, in, out, err, env);
@@ -1395,13 +1397,8 @@ relocate_fd (int fd, int minfd)
       int new = fcntl (fd, F_DUPFD_CLOEXEC, minfd);
       if (new == -1)
         {
-          const char *message_1 = "Error while setting up child: ";
-          const char *errmessage = strerror (errno);
-          const char *message_2 = "\n";
-          emacs_write (2, message_1, strlen (message_1));
-          emacs_write (2, errmessage, strlen (errmessage));
-          emacs_write (2, message_2, strlen (message_2));
-          _exit (1);
+          emacs_perror ("while setting up child");
+          _exit (EXIT_CANCELED);
         }
       emacs_close (fd);
       return new;