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gdm3/daemon/main.c
Daniel Baumann 83b37a3d94
Adding upstream version 48.0.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
2025-06-22 19:45:29 +02:00

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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*-
*
* Copyright (C) 2007 William Jon McCann <mccann@jhu.edu>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#include "config.h"
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <pwd.h>
#include <grp.h>
#include <sys/wait.h>
#include <locale.h>
#include <signal.h>
#include <glib.h>
#include <glib/gi18n.h>
#include <glib/gstdio.h>
#include <glib-object.h>
#include <gio/gio.h>
#include "gdm-manager.h"
#include "gdm-log.h"
#include "gdm-common.h"
#include "gdm-settings.h"
#include "gdm-settings-direct.h"
#include "gdm-settings-keys.h"
#define GDM_DBUS_NAME "org.gnome.DisplayManager"
static GDBusConnection *get_system_bus (void);
static gboolean bus_reconnect (void);
extern char **environ;
static GdmManager *manager = NULL;
static int name_id = -1;
static GdmSettings *settings = NULL;
static uid_t gdm_uid = -1;
static gid_t gdm_gid = -1;
static gboolean
timed_exit_cb (GMainLoop *loop)
{
g_main_loop_quit (loop);
return FALSE;
}
static void
bus_connection_closed (void)
{
g_debug ("Disconnected from D-Bus");
if (manager == NULL) {
/* probably shutting down or something */
return;
}
g_clear_object (&manager);
g_timeout_add_seconds (3, (GSourceFunc)bus_reconnect, NULL);
}
static GDBusConnection *
get_system_bus (void)
{
GError *error;
GDBusConnection *bus;
error = NULL;
bus = g_bus_get_sync (G_BUS_TYPE_SYSTEM, NULL, &error);
if (bus == NULL) {
g_warning ("Couldn't connect to system bus: %s",
error->message);
g_error_free (error);
goto out;
}
g_signal_connect (bus, "closed",
G_CALLBACK (bus_connection_closed), NULL);
g_dbus_connection_set_exit_on_close (bus, FALSE);
out:
return bus;
}
static void
delete_pid (void)
{
g_unlink (GDM_PID_FILE);
}
static void
write_pid (void)
{
int pf;
ssize_t written;
char pid[9];
errno = 0;
pf = open (GDM_PID_FILE, O_WRONLY|O_CREAT|O_TRUNC|O_EXCL, 0644);
if (pf < 0) {
g_warning (_("Cannot write PID file %s: possibly out of disk space: %s"),
GDM_PID_FILE,
g_strerror (errno));
return;
}
snprintf (pid, sizeof (pid), "%lu\n", (long unsigned) getpid ());
errno = 0;
written = write (pf, pid, strlen (pid));
close (pf);
if (written < 0) {
g_warning (_("Cannot write PID file %s: possibly out of disk space: %s"),
GDM_PID_FILE,
g_strerror (errno));
return;
}
atexit (delete_pid);
}
static gboolean
ensure_dir_with_perms (const char *path,
uid_t uid,
gid_t gid,
mode_t mode,
GError **error)
{
gboolean ret = FALSE;
if (g_mkdir_with_parents (path, 0755) == -1) {
g_set_error_literal (error, G_IO_ERROR, g_io_error_from_errno (errno), g_strerror (errno));
goto out;
}
if (g_chmod (path, mode) == -1) {
g_set_error_literal (error, G_IO_ERROR, g_io_error_from_errno (errno), g_strerror (errno));
goto out;
}
if (chown (path, uid, gid) == -1) {
g_set_error_literal (error, G_IO_ERROR, g_io_error_from_errno (errno), g_strerror (errno));
goto out;
}
ret = TRUE;
out:
return ret;
}
static void
gdm_daemon_ensure_dirs (uid_t uid,
gid_t gid)
{
GError *error = NULL;
/* Set up /var/run/gdm */
if (!ensure_dir_with_perms (GDM_RAN_ONCE_MARKER_DIR, 0, gid, 0711, &error)) {
g_critical (_("Failed to create ran once marker dir %s: %s"),
GDM_RAN_ONCE_MARKER_DIR, error->message);
}
/* Set up /var/log/gdm */
if (!ensure_dir_with_perms (LOGDIR, 0, gid, 0711, &error)) {
g_critical (_("Failed to create LogDir %s: %s"),
LOGDIR, error->message);
}
}
static void
gdm_daemon_lookup_user (uid_t *uidp,
gid_t *gidp)
{
char *username;
char *groupname;
uid_t uid;
gid_t gid;
struct passwd *pwent;
struct group *grent;
username = NULL;
groupname = NULL;
uid = 0;
gid = 0;
gdm_settings_direct_get_string (GDM_KEY_USER, &username);
gdm_settings_direct_get_string (GDM_KEY_GROUP, &groupname);
if (username == NULL || groupname == NULL) {
return;
}
g_debug ("Changing user:group to %s:%s", username, groupname);
/* Lookup user and groupid for the GDM user */
gdm_get_pwent_for_name (username, &pwent);
/* Set uid and gid */
if G_UNLIKELY (pwent == NULL) {
g_critical (_("Cant find the GDM user “%s”. Aborting!"), username);
} else {
uid = pwent->pw_uid;
}
if G_UNLIKELY (uid == 0) {
g_critical (_("The GDM user should not be root. Aborting!"));
}
grent = getgrnam (groupname);
if G_UNLIKELY (grent == NULL) {
g_critical (_("Cant find the GDM group “%s”. Aborting!"), groupname);
} else {
gid = grent->gr_gid;
}
if G_UNLIKELY (gid == 0) {
g_critical (_("The GDM group should not be root. Aborting!"));
}
if (uidp != NULL) {
*uidp = uid;
}
if (gidp != NULL) {
*gidp = gid;
}
g_free (username);
g_free (groupname);
}
static gboolean
on_shutdown_signal_cb (gpointer user_data)
{
GMainLoop *mainloop = user_data;
g_main_loop_quit (mainloop);
return FALSE;
}
static gboolean
on_sighup_cb (gpointer user_data)
{
g_debug ("Got HUP signal");
gdm_settings_reload (settings);
return TRUE;
}
static gboolean
is_debug_set (void)
{
gboolean debug;
gdm_settings_direct_get_boolean (GDM_KEY_DEBUG, &debug);
return debug;
}
/* SIGUSR1 is used by the X server to tell us that we're ready, so
* block it. We'll unblock it in the worker thread in gdm-server.c
*/
static void
block_sigusr1 (void)
{
sigset_t mask;
sigemptyset (&mask);
sigaddset (&mask, SIGUSR1);
sigprocmask (SIG_BLOCK, &mask, NULL);
}
int
main (int argc,
char **argv)
{
GMainLoop *main_loop;
GOptionContext *context;
GError *error = NULL;
gboolean res;
static gboolean do_timed_exit = FALSE;
static gboolean print_version = FALSE;
static gboolean fatal_warnings = FALSE;
static GOptionEntry entries [] = {
{ "fatal-warnings", 0, 0, G_OPTION_ARG_NONE, &fatal_warnings, N_("Make all warnings fatal"), 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 },
{ NULL }
};
block_sigusr1 ();
bindtextdomain (GETTEXT_PACKAGE, GNOMELOCALEDIR);
textdomain (GETTEXT_PACKAGE);
setlocale (LC_ALL, "");
context = g_option_context_new (_("GNOME Display Manager"));
g_option_context_add_main_entries (context, entries, NULL);
error = NULL;
res = g_option_context_parse (context, &argc, &argv, &error);
g_option_context_free (context);
if (! res) {
g_printerr ("Failed to parse options: %s\n", error->message);
g_error_free (error);
return EXIT_FAILURE;
}
if (print_version) {
g_print ("GDM %s\n", VERSION);
return EXIT_SUCCESS;
}
/* XDM compliant error message */
if (getuid () != 0) {
/* make sure the pid file doesn't get wiped */
g_printerr ("%s\n", _("Only the root user can run GDM"));
return EXIT_FAILURE;
}
if (fatal_warnings) {
GLogLevelFlags fatal_mask;
fatal_mask = g_log_set_always_fatal (G_LOG_FATAL_MASK);
fatal_mask |= G_LOG_LEVEL_WARNING | G_LOG_LEVEL_CRITICAL;
g_log_set_always_fatal (fatal_mask);
}
gdm_log_init ();
settings = gdm_settings_new ();
if (! gdm_settings_direct_init (settings, DATADIR "/gdm/gdm.schemas", "/")) {
g_warning ("Unable to initialize settings");
return EXIT_FAILURE;
}
gdm_log_set_debug (is_debug_set ());
gdm_daemon_lookup_user (&gdm_uid, &gdm_gid);
gdm_daemon_ensure_dirs (gdm_uid, gdm_gid);
/* Connect to the bus, own the name and start the manager */
bus_reconnect ();
/* pid file */
delete_pid ();
write_pid ();
g_chdir ("/");
main_loop = g_main_loop_new (NULL, FALSE);
g_unix_signal_add (SIGTERM, on_shutdown_signal_cb, main_loop);
g_unix_signal_add (SIGINT, on_shutdown_signal_cb, main_loop);
g_unix_signal_add (SIGHUP, on_sighup_cb, NULL);
if (do_timed_exit) {
g_timeout_add_seconds (30, (GSourceFunc) timed_exit_cb, main_loop);
}
g_main_loop_run (main_loop);
g_debug ("GDM finished, cleaning up...");
g_clear_object (&manager);
g_clear_object (&settings);
gdm_settings_direct_shutdown ();
gdm_log_shutdown ();
g_main_loop_unref (main_loop);
return EXIT_SUCCESS;
}
static void
on_name_acquired (GDBusConnection *bus,
const char *name,
gpointer user_data)
{
gboolean xdmcp_enabled;
gboolean show_local_greeter;
gboolean remote_login_enabled;
manager = gdm_manager_new ();
if (manager == NULL) {
g_warning ("Could not construct manager object");
exit (EXIT_FAILURE);
}
g_debug ("Successfully connected to D-Bus");
show_local_greeter = TRUE;
gdm_settings_direct_get_boolean (GDM_KEY_SHOW_LOCAL_GREETER, &show_local_greeter);
gdm_manager_set_show_local_greeter (manager, show_local_greeter);
xdmcp_enabled = FALSE;
gdm_settings_direct_get_boolean (GDM_KEY_XDMCP_ENABLE, &xdmcp_enabled);
gdm_manager_set_xdmcp_enabled (manager, xdmcp_enabled);
remote_login_enabled = FALSE;
gdm_settings_direct_get_boolean (GDM_KEY_REMOTE_LOGIN_ENABLE, &remote_login_enabled);
gdm_manager_set_remote_login_enabled (manager, remote_login_enabled);
gdm_manager_start (manager);
}
static void
on_name_lost (GDBusConnection *bus,
const char *name,
gpointer user_data)
{
g_debug ("Lost GDM name on bus");
bus_connection_closed ();
}
static gboolean
bus_reconnect ()
{
GDBusConnection *bus;
gboolean ret;
ret = TRUE;
bus = get_system_bus ();
if (bus == NULL) {
goto out;
}
name_id = g_bus_own_name_on_connection (bus,
GDM_DBUS_NAME,
G_BUS_NAME_OWNER_FLAGS_NONE,
on_name_acquired,
on_name_lost,
NULL,
NULL);
ret = FALSE;
out:
return ret;
}