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[Emacs-diffs] Changes to emacs/src/emacs.c,v
From: |
Stefan Monnier |
Subject: |
[Emacs-diffs] Changes to emacs/src/emacs.c,v |
Date: |
Tue, 28 Oct 2008 01:02:49 +0000 |
CVSROOT: /sources/emacs
Module name: emacs
Changes by: Stefan Monnier <monnier> 08/10/28 01:02:48
Index: emacs.c
===================================================================
RCS file: /sources/emacs/emacs/src/emacs.c,v
retrieving revision 1.451
retrieving revision 1.452
diff -u -b -r1.451 -r1.452
--- emacs.c 27 Oct 2008 07:02:36 -0000 1.451
+++ emacs.c 28 Oct 2008 01:02:46 -0000 1.452
@@ -235,8 +235,6 @@
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;
@@ -244,6 +242,8 @@
startup. */
static int daemon_pipe[2];
+#define IS_DAEMON (daemon_pipe[1] != 0)
+
/* Save argv and argc. */
char **initial_argv;
int initial_argc;
@@ -1086,6 +1086,20 @@
/* 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')
@@ -1131,7 +1145,6 @@
daemon_name = xstrdup (dname_arg);
/* Close unused reading end of the pipe. */
close (daemon_pipe[0]);
- is_daemon = 1;
#ifdef HAVE_SETSID
setsid();
#endif
@@ -2429,7 +2442,7 @@
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
@@ -2439,12 +2452,14 @@
}
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)
@@ -2460,7 +2475,14 @@
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;
@@ -2584,6 +2606,9 @@
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
- [Emacs-diffs] Changes to emacs/src/emacs.c,v, Glenn Morris, 2008/10/03
- [Emacs-diffs] Changes to emacs/src/emacs.c,v, Chong Yidong, 2008/10/06
- [Emacs-diffs] Changes to emacs/src/emacs.c,v, Jan Djärv, 2008/10/21
- [Emacs-diffs] Changes to emacs/src/emacs.c,v, Dan Nicolaescu, 2008/10/26
- [Emacs-diffs] Changes to emacs/src/emacs.c,v, Dan Nicolaescu, 2008/10/27
- [Emacs-diffs] Changes to emacs/src/emacs.c,v,
Stefan Monnier <=
- [Emacs-diffs] Changes to emacs/src/emacs.c,v, Dan Nicolaescu, 2008/10/28
- [Emacs-diffs] Changes to emacs/src/emacs.c,v, Chong Yidong, 2008/10/29