Commit 322aea6d authored by Paul Eggert's avatar Paul Eggert

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
parent 220cb2bd
2012-10-31 Paul Eggert <eggert@cs.ucla.edu>
Fix crash when using Emacs as commit editor for git (Bug#12697).
* 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.
2012-10-31 Michael Albinus <michael.albinus@gmx.de>
* dbusbind.c: Fix cut'n'waste error. Use HAVE_DBUS_VALIDATE_INTERFACE.
......
......@@ -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);
......
......@@ -112,6 +112,14 @@ You lose; /* Emacs for DOS must be compiled with DJGPP */
#endif
/* End of gnulib-related stuff. */
#ifndef HAVE_SETPGID
# ifdef USG
# define setpgid(pid, pgid) setpgrp ()
# else
# define setpgid(pid, pgid) setpgrp (pid, pgid)
# endif
#endif
/* Define one of these for easier conditionals. */
#ifdef HAVE_X_WINDOWS
/* We need a little extra space, see ../../lisp/loadup.el and the
......
......@@ -6283,6 +6283,8 @@ init_display (void)
struct terminal *t;
struct frame *f = XFRAME (selected_frame);
init_foreground_group ();
/* Open a display on the controlling tty. */
t = init_tty (0, terminal_type, 1); /* Errors are fatal. */
......
......@@ -1091,19 +1091,14 @@ Using an Emacs configured with --with-x-toolkit=lucid does not have this problem
#endif /* DOS_NT */
}
#if defined (HAVE_PTHREAD) && !defined (SYSTEM_MALLOC) && !defined (DOUG_LEA_MALLOC)
if (! noninteractive)
{
#if defined (USG5) && defined (INTERRUPT_INPUT)
setpgrp ();
#endif
#if defined (HAVE_PTHREAD) && !defined (SYSTEM_MALLOC) && !defined (DOUG_LEA_MALLOC)
{
extern void malloc_enable_thread (void);
extern void malloc_enable_thread (void);
malloc_enable_thread ();
}
#endif
malloc_enable_thread ();
}
#endif
init_signals (dumping);
......
......@@ -3474,6 +3474,7 @@ struct terminal;
extern char *get_current_dir_name (void);
#endif
extern void stuff_char (char c);
extern void init_foreground_group (void);
extern void init_sigio (int);
extern void sys_subshell (void);
extern void sys_suspend (void);
......
......@@ -1759,12 +1759,10 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
#endif
}
#else /* not HAVE_SETSID */
#ifdef USG
/* It's very important to call setpgrp here and no time
/* It's very important to call setpgid here and no time
afterwards. Otherwise, we lose our controlling tty which
is set when we open the pty. */
setpgrp ();
#endif /* USG */
setpgid (0, 0);
#endif /* not HAVE_SETSID */
#if defined (LDISC1)
if (pty_flag && xforkin >= 0)
......@@ -1802,11 +1800,7 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
/* In order to get a controlling terminal on some versions
of BSD, it is necessary to put the process in pgrp 0
before it opens the terminal. */
#ifdef HAVE_SETPGID
setpgid (0, 0);
#else
setpgrp (0, 0);
#endif
#endif
}
#endif /* TIOCNOTTY */
......
......@@ -682,6 +682,75 @@ ignore_sigio (void)
#endif
}
/* Saving and restoring the process group of Emacs's terminal. */
/* The process group of which Emacs was a member when it initially
started.
If Emacs was in its own process group (i.e. inherited_pgroup ==
getpid ()), then we know we're running under a shell with job
control (Emacs would never be run as part of a pipeline).
Everything is fine.
If Emacs was not in its own process group, then we know we're
running under a shell (or a caller) that doesn't know how to
separate itself from Emacs (like sh). Emacs must be in its own
process group in order to receive SIGIO correctly. In this
situation, we put ourselves in our own pgroup, forcibly set the
tty's pgroup to our pgroup, and make sure to restore and reinstate
the tty's pgroup just like any other terminal setting. If
inherited_group was not the tty's pgroup, then we'll get a
SIGTTmumble when we try to change the tty's pgroup, and a CONT if
it goes foreground in the future, which is what should happen. */
static pid_t inherited_pgroup;
void
init_foreground_group (void)
{
pid_t pgrp = EMACS_GETPGRP (0);
inherited_pgroup = getpid () == pgrp ? 0 : pgrp;
}
/* Safely set a controlling terminal FD's process group to PGID.
If we are not in the foreground already, POSIX requires tcsetpgrp
to deliver a SIGTTOU signal, which would stop us. This is an
annoyance, so temporarily ignore the signal.
In practice, platforms lacking SIGTTOU also lack tcsetpgrp, so
skip all this unless SIGTTOU is defined. */
static void
tcsetpgrp_without_stopping (int fd, pid_t pgid)
{
#ifdef SIGTTOU
signal_handler_t handler;
block_input ();
handler = signal (SIGTTOU, SIG_IGN);
tcsetpgrp (fd, pgid);
signal (SIGTTOU, handler);
unblock_input ();
#endif
}
/* Split off the foreground process group to Emacs alone. When we are
in the foreground, but not started in our own process group,
redirect the tty device handle FD to point to our own process
group. FD must be the file descriptor of the controlling tty. */
static void
narrow_foreground_group (int fd)
{
if (inherited_pgroup && setpgid (0, 0) == 0)
tcsetpgrp_without_stopping (fd, getpid ());
}
/* Set the tty to our original foreground group. */
static void
widen_foreground_group (int fd)
{
if (inherited_pgroup && setpgid (0, inherited_pgroup) == 0)
tcsetpgrp_without_stopping (fd, inherited_pgroup);
}
/* Getting and setting emacs_tty structures. */
......@@ -799,6 +868,8 @@ init_sys_modes (struct tty_display_info *tty_out)
if (!tty_out->output)
return; /* The tty is suspended. */
narrow_foreground_group (fileno (tty_out->input));
if (! tty_out->old_tty)
tty_out->old_tty = xmalloc (sizeof *tty_out->old_tty);
......@@ -1231,6 +1302,7 @@ reset_sys_modes (struct tty_display_info *tty_out)
dos_ttcooked ();
#endif
widen_foreground_group (fileno (tty_out->input));
}
#ifdef HAVE_PTYS
......
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