+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.
#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;
{
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);
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);
#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
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. */
#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);
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);
#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)
/* 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 */
#endif
}
+\f
+/* 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);
+}
\f
/* Getting and setting emacs_tty structures. */
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);
dos_ttcooked ();
#endif
+ widen_foreground_group (fileno (tty_out->input));
}
\f
#ifdef HAVE_PTYS
projects / emacs.git / commitdiff