From 722d31dc8823090b651b103f0194b6380f2d458e Mon Sep 17 00:00:00 2001
From: Alexandre Rostovtsev <tetromino@gentoo.org>
Date: Tue, 25 Sep 2012 22:30:29 -0400
Subject: [PATCH] daemonize so that the boot process can continue
Gentoo bug: #236701
Based on original patch by Dan Nicholson <dbn.lists@gmail.com> and
Gilles Dartiguelongue <eva@gentoo.org>.
Fork gdm-binary, except when -nodaemon is used
Makes the gdm main binary fork and daemonize unless the -nodaemon or
--nodaemon options are used. Provides compatibility with xdm. Fixes
bug #550170.
In daemonized mode, start a new process group, and kill it in our signal
handlers, so that killing gdm kills its spawned processes, and so that
"/etc/init.d/xdm stop" actually works.
---
configure.ac | 4 ++++
daemon/Makefile.am | 1 +
daemon/main.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 65 insertions(+)
diff --git a/configure.ac b/configure.ac
index 61a43d6..a851ba5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -99,6 +99,10 @@ PKG_CHECK_MODULES(DAEMON,
AC_SUBST(DAEMON_CFLAGS)
AC_SUBST(DAEMON_LIBS)
+PKG_CHECK_MODULES(LIBDAEMON, libdaemon)
+AC_SUBST(LIBDAEMON_CFLAGS)
+AC_SUBST(LIBDAEMON_LIBS)
+
GLIB_GSETTINGS
PKG_CHECK_MODULES(NSS,
diff --git a/daemon/Makefile.am b/daemon/Makefile.am
index bb84765..cf89b47 100644
--- a/daemon/Makefile.am
+++ b/daemon/Makefile.am
@@ -380,6 +380,7 @@ gdm_binary_LDADD = \
$(top_builddir)/common/libgdmcommon.la \
$(XLIB_LIBS) \
$(DAEMON_LIBS) \
+ $(LIBDAEMON_LIBS) \
$(XDMCP_LIBS) \
$(LIBWRAP_LIBS) \
$(SYSTEMD_LIBS) \
diff --git a/daemon/main.c b/daemon/main.c
index 3b8572c..c2fe4fe 100644
--- a/daemon/main.c
+++ b/daemon/main.c
@@ -34,6 +34,8 @@
#include <locale.h>
#include <signal.h>
+#include <libdaemon/dfork.h>
+
#include <glib.h>
#include <glib/gi18n.h>
#include <glib/gstdio.h>
@@ -336,16 +338,26 @@ signal_cb (int signo,
gpointer data)
{
int ret;
+ static gboolean ignore_signals = FALSE;
g_debug ("Got callback for signal %d", signo);
ret = TRUE;
+ /* don't commit suicide before killing everyone in our process group */
+ if (ignore_signals)
+ return ret;
+
switch (signo) {
case SIGFPE:
case SIGPIPE:
/* let the fatal signals interrupt us */
g_debug ("Caught signal %d, shutting down abnormally.", signo);
+ /* if we daemonized, kill all the processes we spawned */
+ ignore_signals = TRUE;
+ kill (-getpid (), signo);
+ ignore_signals = FALSE;
+
ret = FALSE;
break;
@@ -354,6 +366,11 @@ signal_cb (int signo,
case SIGTERM:
/* let the fatal signals interrupt us */
g_debug ("Caught signal %d, shutting down normally.", signo);
+ /* if we daemonized, kill all the processes we spawned */
+ ignore_signals = TRUE;
+ kill (-getpid (), signo);
+ ignore_signals = FALSE;
+
ret = FALSE;
break;
@@ -418,13 +435,16 @@ main (int argc,
GOptionContext *context;
GError *error;
int ret;
+ int i;
gboolean res;
GdmSignalHandler *signal_handler;
static gboolean do_timed_exit = FALSE;
static gboolean print_version = FALSE;
static gboolean fatal_warnings = FALSE;
+ static gboolean no_daemon = FALSE;
static GOptionEntry entries [] = {
{ "fatal-warnings", 0, 0, G_OPTION_ARG_NONE, &fatal_warnings, N_("Make all warnings fatal"), NULL },
+ { "nodaemon", 0, 0, G_OPTION_ARG_NONE, &no_daemon, N_("Do not fork into the background"), NULL },
{ "timed-exit", 0, 0, G_OPTION_ARG_NONE, &do_timed_exit, N_("Exit after a time (for debugging)"), NULL },
{ "version", 0, 0, G_OPTION_ARG_NONE, &print_version, N_("Print GDM version"), NULL },
@@ -439,6 +459,14 @@ main (int argc,
g_type_init ();
+ /* preprocess the arguments to support the xdm style
+ * -nodaemon option
+ */
+ for (i = 0; i < argc; i++) {
+ if (strcmp (argv[i], "-nodaemon") == 0)
+ argv[i] = "--nodaemon";
+ }
+
context = g_option_context_new (_("GNOME Display Manager"));
g_option_context_add_main_entries (context, entries, NULL);
g_option_context_set_ignore_unknown_options (context, TRUE);
@@ -465,6 +493,33 @@ main (int argc,
g_log_set_always_fatal (fatal_mask);
}
+ if (!no_daemon) {
+ pid_t pid;
+ if (daemon_retval_init () < 0) {
+ g_warning ("Failed to create pipe");
+ exit (-1);
+ }
+ if ((pid = daemon_fork ()) < 0) {
+ /* Fork failed */
+ daemon_retval_done ();
+ exit (1);
+ } else if (pid) {
+ /* Parent process: wait 20s for daemon_retval_send() in the daemon process */
+ if ((ret = daemon_retval_wait (20)) < 0) {
+ g_warning ("Timed out waiting for daemon process: %s", strerror(errno));
+ exit (255);
+ } else if (ret > 0) {
+ g_warning ("Daemon process returned error code %d", ret);
+ exit (ret);
+ }
+ exit (0);
+ }
+ /* Daemon process */
+ daemon_close_all (-1);
+ /* Start a new process group so that killing the daemon will kill the processes that it spawned */
+ setsid ();
+ }
+
gdm_log_init ();
settings = gdm_settings_new ();
@@ -519,6 +574,9 @@ main (int argc,
g_timeout_add_seconds (30, (GSourceFunc) timed_exit_cb, main_loop);
}
+ if (!no_daemon)
+ daemon_retval_send (0);
+
g_main_loop_run (main_loop);
g_debug ("GDM finished, cleaning up...");
@@ -535,6 +593,8 @@ main (int argc,
ret = 0;
out:
+ if (!no_daemon)
+ daemon_retval_send (ret);
return ret;
}
--
1.7.12