/* Fully extensible Emacs, running on Unix, intended for GNU.
Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 1998, 1999,
- 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
Free Software Foundation, Inc.
This file is part of GNU Emacs.
int noninteractive1;
-/* Nonzero means Emacs was started as a daemon. */
-int is_daemon = 0;
/* Name for the server started by the daemon.*/
static char *daemon_name;
/* Pipe used to send exit notification to the daemon parent at
startup. */
-static int daemon_pipe[2];
+int daemon_pipe[2];
/* Save argv and argc. */
char **initial_argv;
Action options:\n\
\n\
FILE visit FILE using find-file\n\
-+LINE go to line LINE in next FILE\n\
-+LINE:COLUMN go to line LINE, column COLUMN, in next FILE\n\
++LINE go to line LINE in next FILE\n\
++LINE:COLUMN go to line LINE, column COLUMN, in next FILE\n\
--directory, -L DIR add DIR to variable load-path\n\
--eval EXPR evaluate Emacs Lisp expression EXPR\n\
--execute EXPR evaluate Emacs Lisp expression EXPR\n\
/* Start as a daemon: fork a new child process which will run the
rest of the initialization code, then exit.
+ Detaching a daemon requires the following steps:
+ - fork
+ - setsid
+ - exit the parent
+ - close the tty file-descriptors
+
+ We only want to do the last 2 steps once the daemon is ready to
+ serve requests, i.e. after loading .emacs (initialization).
+ OTOH initialization may start subprocesses (e.g. ispell) and these
+ should be run from the proper process (the one that will end up
+ running as daemon) and with the proper "session id" in order for
+ them to keep working after detaching, so fork and setsid need to be
+ performed before initialization.
+
We want to avoid exiting before the server socket is ready, so
use a pipe for synchronization. The parent waits for the child
to close its end of the pipe (using `daemon-initialized')
fprintf (stderr, "Error reading status from child\n");
exit (1);
}
+ else if (retval == 0)
+ {
+ fprintf (stderr, "Error: server did not start correctly\n");
+ exit (1);
+ }
close (daemon_pipe[0]);
exit (0);
daemon_name = xstrdup (dname_arg);
/* Close unused reading end of the pipe. */
close (daemon_pipe[0]);
- is_daemon = 1;
+ /* Make sure that the used end of the pipe is closed on exec, so
+ that it is not accessible to programs started from .emacs. */
+ fcntl (daemon_pipe[1], F_SETFD, FD_CLOEXEC);
+
#ifdef HAVE_SETSID
setsid();
#endif
If the daemon was given a name argument, return that name. */)
()
{
- if (is_daemon)
+ if (IS_DAEMON)
if (daemon_name)
return build_string (daemon_name);
else
}
DEFUN ("daemon-initialized", Fdaemon_initialized, Sdaemon_initialized, 0, 0, 0,
- doc: /* Mark the Emacs daemon as being initialized. */)
+ doc: /* Mark the Emacs daemon as being initialized.
+This finishes the daemonization process by doing the other half of detaching
+from the parent process and its tty file descriptors. */)
()
{
int nfd;
- if (!is_daemon)
+ if (!IS_DAEMON)
error ("This function can only be called if emacs is run as a daemon");
if (daemon_pipe[1] < 0)
error ("This function can only be called after loading the init files");
/* Get rid of stdin, stdout and stderr. */
- open ("/dev/null", O_RDWR);
+ nfd = open ("/dev/null", O_RDWR);
dup2 (nfd, 0);
dup2 (nfd, 1);
dup2 (nfd, 2);
close (nfd);
- /* Closing the pipe will notify the parent that it can exit. */
+ /* Closing the pipe will notify the parent that it can exit.
+ FIXME: In case some other process inherited the pipe, closing it here
+ won't notify the parent because it's still open elsewhere, so we
+ additionally send a byte, just to make sure the parent really exits.
+ Instead, we should probably close the pipe in start-process and
+ call-process to make sure the pipe is never inherited by
+ subprocesses. */
+ write (daemon_pipe[1], "\n", 1);
close (daemon_pipe[1]);
/* Set it to an invalid value so we know we've already run this function. */
daemon_pipe[1] = -1;
doc: /* Value of `current-time' after loading the init files.
This is nil during initialization. */);
Vafter_init_time = Qnil;
+
+ /* Make sure IS_DAEMON starts up as false. */
+ daemon_pipe[1] = 0;
}
/* arch-tag: 7bfd356a-c720-4612-8ab6-aa4222931c2e