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bug#1058: 23.0.60; emacs --daemon should not return until socket is read
From: |
Romain Francoise |
Subject: |
bug#1058: 23.0.60; emacs --daemon should not return until socket is ready |
Date: |
Thu, 02 Oct 2008 19:54:51 +0200 |
Here's version one of a patch for this, please let me know what you
think.
diff --git a/lisp/startup.el b/lisp/startup.el
index 5bd73f9..22c92c5 100644
--- a/lisp/startup.el
+++ b/lisp/startup.el
@@ -1224,7 +1224,8 @@ opening the first frame (e.g. open a connection to an X
server).")
;; processing all command line arguments to allow e.g. `server-name'
;; to be changed before the server starts.
(when (daemonp)
- (server-start))
+ (server-start)
+ (daemon-initialized))
;; Run emacs-session-restore (session management) if started by
;; the session manager and we have a session manager connection.
diff --git a/src/emacs.c b/src/emacs.c
index f94d2d3..d4d16b7 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -235,6 +235,13 @@ int noninteractive1;
/* Nonzero means Emacs was started as a daemon. */
int is_daemon = 0;
+/* Set nonzero after the daemon has finished initializing. */
+int daemon_initialized = 0;
+
+/* Pipe used to send exit notification to the daemon parent at
+ startup. */
+int daemon_pipe[2];
+
/* Save argv and argc. */
char **initial_argv;
int initial_argc;
@@ -1074,16 +1081,56 @@ main (int argc, char **argv)
if (argmatch (argv, argc, "-daemon", "--daemon", 5, NULL, &skip_args))
{
#ifndef DOS_NT
- pid_t f = fork ();
+ pid_t f;
int nfd;
+
+ /* Start as a daemon: fork a new child process which will run the
+ rest of the initialization code, then exit.
+
+ 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')
+ before exiting. */
+ if (pipe (daemon_pipe) == -1)
+ {
+ fprintf (stderr, "Cannot pipe!\n");
+ exit (1);
+ }
+
+ f = fork ();
if (f > 0)
- exit (0);
+ {
+ int retval;
+ char buf[1];
+
+ /* Close unused writing end of the pipe. */
+ close (daemon_pipe[1]);
+
+ /* Just wait for the child to close its end of the pipe. */
+ do
+ {
+ retval = read (daemon_pipe[0], &buf, 1);
+ }
+ while (retval == -1 && errno == EINTR);
+
+ if (retval < 0)
+ {
+ fprintf (stderr, "Error reading status from child\n");
+ exit (1);
+ }
+
+ close (daemon_pipe[0]);
+ exit (0);
+ }
if (f < 0)
{
fprintf (stderr, "Cannot fork!\n");
exit (1);
}
+ /* Close unused reading end of the pipe. */
+ close (daemon_pipe[0]);
+
nfd = open ("/dev/null", O_RDWR);
dup2 (nfd, 0);
dup2 (nfd, 1);
@@ -2389,6 +2436,24 @@ DEFUN ("daemonp", Fdaemonp, Sdaemonp, 0, 0, 0,
return is_daemon ? Qt : Qnil;
}
+DEFUN ("daemon-initialized", Fdaemon_initialized, Sdaemon_initialized, 0, 0, 0,
+ doc: /* Mark the Emacs daemon as being initialized. */)
+ ()
+{
+ if (is_daemon)
+ {
+ if (! daemon_initialized)
+ {
+ /* Closing the pipe will notify the parent that it can exit. */
+ close (daemon_pipe[1]);
+ daemon_initialized = 1;
+ }
+ }
+ else
+ error ("Emacs was not started as a daemon");
+ return daemon_initialized ? Qt : Qnil;
+}
+
void
syms_of_emacs ()
{
@@ -2408,6 +2473,7 @@ syms_of_emacs ()
defsubr (&Sinvocation_name);
defsubr (&Sinvocation_directory);
defsubr (&Sdaemonp);
+ defsubr (&Sdaemon_initialized);
DEFVAR_LISP ("command-line-args", &Vcommand_line_args,
doc: /* Args passed by shell to Emacs, as a list of strings.
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, (continued)
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Dan Nicolaescu, 2008/10/12
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Stefan Monnier, 2008/10/13
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Dan Nicolaescu, 2008/10/13
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Stefan Monnier, 2008/10/13
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Dan Nicolaescu, 2008/10/14
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Dan Nicolaescu, 2008/10/27
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Trent W. Buck, 2008/10/02
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready,
Romain Francoise <=
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Dan Nicolaescu, 2008/10/02
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Dan Nicolaescu, 2008/10/06
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Stefan Monnier, 2008/10/07
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Dan Nicolaescu, 2008/10/07
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Trent W. Buck, 2008/10/07
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Stefan Monnier, 2008/10/07
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Stefan Monnier, 2008/10/07
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Romain Francoise, 2008/10/07
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Dan Nicolaescu, 2008/10/07
- bug#1058: 23.0.60; emacs --daemon should not return until socket is ready, Dan Nicolaescu, 2008/10/26