Package: emacs;
Reported by: Markus Triska <markus.triska <at> gmx.at>
Date: Sun, 13 Jul 2008 17:50:03 UTC
Severity: normal
Done: Chong Yidong <cyd <at> stupidchicken.com>
Bug is archived. No further changes may be made.
View this message in rfc822 format
From: YAMAMOTO Mitsuharu <mituharu <at> math.s.chiba-u.ac.jp> To: Markus Triska <markus.triska <at> gmx.at>, 554 <at> debbugs.gnu.org Cc: YAMAMOTO Mitsuharu <mituharu <at> math.s.chiba-u.ac.jp> Subject: bug#554: OSX: with-temp-buffer kills unrelated processes Date: Wed, 16 Jul 2008 18:17:52 +0900
>>>>> On Mon, 14 Jul 2008 19:26:52 +0900, YAMAMOTO Mitsuharu <mituharu <at> math.s.chiba-u.ac.jp> said:
> It seems that the child process receives SIGHUP before it calls
> execvp. As the child process is still running the Emacs executable,
> it sends SIGHUP to all the subprocesses when it receives SIGHUP
> (fatal_error_signal -> shut_down_emacs -> kill_buffer_processes).
> I think these behaviors are not observable in other platforms,
> because they use vfork, and the parent side effectively blocks until
> the child side calls execvp or others in its typical
> implementations. Emacs on Darwin is using fork instead of vfork
> because the latter had (or have?) some problems I'm not familiar
> with.
OK, close-on-exec seems to be usable for the `fork' case. How about
the patch below?
YAMAMOTO Mitsuharu
mituharu <at> math.s.chiba-u.ac.jp
Index: src/callproc.c
===================================================================
RCS file: /cvsroot/emacs/emacs/src/callproc.c,v
retrieving revision 1.221.2.3
diff -c -p -r1.221.2.3 callproc.c
*** src/callproc.c 8 Jan 2008 04:30:19 -0000 1.221.2.3
--- src/callproc.c 16 Jul 2008 08:03:57 -0000
*************** static int relocate_fd ();
*** 1192,1199 ****
Therefore, the superior process must save and restore the value
of environ around the vfork and the call to this function.
! SET_PGRP is nonzero if we should put the subprocess into a separate
! process group.
CURRENT_DIR is an elisp string giving the path of the current
directory the subprocess should have. Since we can't really signal
--- 1192,1199 ----
Therefore, the superior process must save and restore the value
of environ around the vfork and the call to this function.
! RET_ON_FAIL is nonzero if we should return from the function on
! failure of execvp rather than calling _exit.
CURRENT_DIR is an elisp string giving the path of the current
directory the subprocess should have. Since we can't really signal
*************** static int relocate_fd ();
*** 1201,1210 ****
executable directory by the parent. */
int
! child_setup (in, out, err, new_argv, set_pgrp, current_dir)
int in, out, err;
register char **new_argv;
! int set_pgrp;
Lisp_Object current_dir;
{
char **env;
--- 1201,1210 ----
executable directory by the parent. */
int
! child_setup (in, out, err, new_argv, ret_on_fail, current_dir)
int in, out, err;
register char **new_argv;
! int ret_on_fail;
Lisp_Object current_dir;
{
char **env;
*************** child_setup (in, out, err, new_argv, set
*** 1412,1418 ****
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);
#endif /* not WINDOWSNT */
#endif /* not MSDOS */
}
--- 1412,1419 ----
emacs_write (1, "Can't exec program: ", 20);
emacs_write (1, new_argv[0], strlen (new_argv[0]));
emacs_write (1, "\n", 1);
! if (!ret_on_fail)
! _exit (1);
#endif /* not WINDOWSNT */
#endif /* not MSDOS */
}
Index: src/process.c
===================================================================
RCS file: /cvsroot/emacs/emacs/src/process.c,v
retrieving revision 1.512.2.12
diff -c -p -r1.512.2.12 process.c
*** src/process.c 27 Feb 2008 15:07:14 -0000 1.512.2.12
--- src/process.c 16 Jul 2008 08:03:58 -0000
*************** create_process (process, new_argv, curre
*** 1842,1847 ****
--- 1842,1850 ----
int inchannel, outchannel;
pid_t pid;
int sv[2];
+ #if !defined (WINDOWSNT) && defined (FD_CLOEXEC)
+ int wait_child_setup[2];
+ #endif
#ifdef POSIX_SIGNALS
sigset_t procmask;
sigset_t blocked;
*************** create_process (process, new_argv, curre
*** 1884,1895 ****
#endif
if (forkin < 0)
report_file_error ("Opening pty", Qnil);
- #if defined (RTU) || defined (UNIPLUS) || defined (DONT_REOPEN_PTY)
- /* In the case that vfork is defined as fork, the parent process
- (Emacs) may send some data before the child process completes
- tty options setup. So we setup tty before forking. */
- child_setup_tty (forkout);
- #endif /* RTU or UNIPLUS or DONT_REOPEN_PTY */
#else
forkin = forkout = -1;
#endif /* not USG, or USG_SUBTTY_WORKS */
--- 1887,1892 ----
*************** create_process (process, new_argv, curre
*** 1924,1929 ****
--- 1921,1945 ----
}
#endif /* not SKTPAIR */
+ #if !defined (WINDOWSNT) && defined (FD_CLOEXEC)
+ {
+ int tem;
+
+ tem = pipe (wait_child_setup);
+ if (tem < 0)
+ report_file_error ("Creating pipe", Qnil);
+ tem = fcntl (wait_child_setup[1], F_GETFD, 0);
+ if (tem >= 0)
+ tem = fcntl (wait_child_setup[1], F_SETFD, tem | FD_CLOEXEC);
+ if (tem < 0)
+ {
+ emacs_close (wait_child_setup[0]);
+ emacs_close (wait_child_setup[1]);
+ report_file_error ("Setting file descriptor flags", Qnil);
+ }
+ }
+ #endif
+
#if 0
/* Replaced by close_process_descs */
set_exclusive_use (inchannel);
*************** create_process (process, new_argv, curre
*** 2174,2189 ****
#endif /* SIGCHLD */
#endif /* !POSIX_SIGNALS */
- #if !defined (RTU) && !defined (UNIPLUS) && !defined (DONT_REOPEN_PTY)
if (pty_flag)
child_setup_tty (xforkout);
- #endif /* not RTU and not UNIPLUS and not DONT_REOPEN_PTY */
#ifdef WINDOWSNT
pid = child_setup (xforkin, xforkout, xforkout,
new_argv, 1, current_dir);
#else /* not WINDOWSNT */
child_setup (xforkin, xforkout, xforkout,
new_argv, 1, current_dir);
#endif /* not WINDOWSNT */
}
environ = save_environ;
--- 2190,2210 ----
#endif /* SIGCHLD */
#endif /* !POSIX_SIGNALS */
if (pty_flag)
child_setup_tty (xforkout);
#ifdef WINDOWSNT
pid = child_setup (xforkin, xforkout, xforkout,
new_argv, 1, current_dir);
#else /* not WINDOWSNT */
+ #ifdef FD_CLOEXEC
+ emacs_close (wait_child_setup[0]);
+ #endif
child_setup (xforkin, xforkout, xforkout,
new_argv, 1, current_dir);
+ #ifdef FD_CLOEXEC
+ emacs_close (wait_child_setup[1]);
+ #endif
+ _exit (1);
#endif /* not WINDOWSNT */
}
environ = save_environ;
*************** create_process (process, new_argv, curre
*** 2235,2240 ****
--- 2256,2276 ----
else
#endif
XPROCESS (process)->tty_name = Qnil;
+
+ #if !defined (WINDOWSNT) && defined (FD_CLOEXEC)
+ /* Wait for child_setup to complete in case that vfork is
+ actually defined as fork. The descriptor wait_child_setup[1]
+ of a pipe is closed at the child side either by close-on-exec
+ on successful execvp or by the explicit emacs_close call
+ before _exit above. */
+ {
+ char dummy;
+
+ emacs_close (wait_child_setup[1]);
+ emacs_read (wait_child_setup[0], &dummy, 1);
+ emacs_close (wait_child_setup[0]);
+ }
+ #endif
}
/* Restore the signal state whether vfork succeeded or not.
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1994-97 Ian Jackson.