daemon: enable smooth transition between plymouth and X

This commit adds optional support for interacting with plymouth
from gdm. This feature can be enabled by passing --with-plymouth
to configure.

Hopefully, this will enable the various distributions that use
plymouth to drop a patch.

https://bugzilla.gnome.org/show_bug.cgi?id=572173

4 files changed, 200 insertions, 1 deletions

diff --git a/configure.ac b/configure.ac
index 35e6e047..81ea23ed 100644
--- a/configure.ac
+++ b/configure.ac
@@ -264,6 +264,10 @@ AC_ARG_WITH(systemd,
             AS_HELP_STRING([--with-systemd],
                            [Add systemd support @<:@default=auto@:>@]),
             [with_systemd=$withval], [with_systemd=auto])
+AC_ARG_WITH(plymouth,
+            AS_HELP_STRING([--with-plymouth],
+                           [Add plymouth support @<:@default=auto@:>@]),
+            [with_plymouth=$withval], [with_plymouth=auto])
 
 AC_ARG_WITH(at-spi-registryd-directory,
             AS_HELP_STRING([--with-at-spi-registryd-directory],
@@ -952,6 +956,33 @@ AC_SUBST(SYSTEMD_X_SERVER)
 AC_DEFINE_UNQUOTED(SYSTEMD_X_SERVER,"$SYSTEMD_X_SERVER",[Path to systemd X server wrapper])
 
 dnl ---------------------------------------------------------------------------
+dnl - Check for plymouth support
+dnl ---------------------------------------------------------------------------
+PKG_CHECK_MODULES(PLYMOUTH,
+                  [ply-boot-client],
+                  [have_plymouth=yes], [have_plymouth=no])
+
+if test "x$with_plymouth" = "xauto" ; then
+        if test x$have_plymouth = xno ; then
+                use_plymouth=no
+        else
+                use_plymouth=yes
+        fi
+else
+        use_plymouth="$with_plymouth"
+fi
+
+if test "x$use_plymouth" != "xno" ; then
+        if test "x$have_plymouth" = "xno"; then
+                AC_MSG_ERROR([Plymouth support explicitly required, but plymouth not found])
+        fi
+
+        AC_DEFINE(WITH_PLYMOUTH, 1, [Define to enable plymouth support])
+fi
+AC_SUBST(PLYMOUTH_CFLAGS)
+AC_SUBST(PLYMOUTH_LIBS)
+
+dnl ---------------------------------------------------------------------------
 dnl - Check for D-Bus
 dnl ---------------------------------------------------------------------------
 
@@ -1537,6 +1568,7 @@ echo \
         SELinux support:          ${with_selinux}
         ConsoleKit support:       ${use_console_kit}
         systemd support:          ${use_systemd}
+        plymouth support:         ${use_plymouth}
         UPower support:           ${have_upower}
         Build with RBAC:          ${msg_rbac_shutdown}
 "
diff --git a/daemon/gdm-server.c b/daemon/gdm-server.c
index d0d8ff9e..6f2a9391 100644
--- a/daemon/gdm-server.c
+++ b/daemon/gdm-server.c
@@ -32,6 +32,7 @@
 #include <pwd.h>
 #include <grp.h>
 #include <signal.h>
+#include <sys/ioctl.h>
 #include <sys/resource.h>
 
 #ifdef HAVE_SYS_PRCTL_H
@@ -42,6 +43,10 @@
 #include <systemd/sd-daemon.h>
 #endif
 
+#ifdef WITH_PLYMOUTH
+#include <linux/vt.h>
+#endif
+
 #include <glib.h>
 #include <glib/gi18n.h>
 #include <glib/gstdio.h>
@@ -751,6 +756,61 @@ gdm_server_spawn (GdmServer  *server,
         return ret;
 }
 
+#ifdef WITH_PLYMOUTH
+static int
+get_active_vt (void)
+{
+        int console_fd;
+        struct vt_stat console_state = { 0 };
+
+        console_fd = open ("/dev/tty0", O_RDONLY | O_NOCTTY);
+
+        if (console_fd < 0) {
+                goto out;
+        }
+
+        if (ioctl (console_fd, VT_GETSTATE, &console_state) < 0) {
+                goto out;
+        }
+
+out:
+        if (console_fd >= 0) {
+                close (console_fd);
+        }
+
+        return console_state.v_active;
+}
+
+static char *
+get_active_vt_as_string (void)
+{
+        int vt;
+
+        vt = get_active_vt ();
+
+        if (vt <= 0) {
+                return NULL;
+        }
+
+        return g_strdup_printf ("vt%d", vt);
+}
+
+gboolean
+gdm_server_start_on_active_vt (GdmServer *server)
+{
+        gboolean res;
+        char *vt;
+
+        g_free (server->priv->command);
+        server->priv->command = g_strdup (X_SERVER " -background none -logverbose 7");
+        vt = get_active_vt_as_string ();
+        res = gdm_server_spawn (server, vt);
+        g_free (vt);
+
+        return res;
+}
+#endif
+
 /**
  * gdm_server_start:
  * @disp: Pointer to a GdmDisplay structure
diff --git a/daemon/gdm-server.h b/daemon/gdm-server.h
index b53d68e5..827f7fa4 100644
--- a/daemon/gdm-server.h
+++ b/daemon/gdm-server.h
@@ -57,6 +57,9 @@ GdmServer *         gdm_server_new       (const char *display_id,
                                           const char *seat_id,
                                           const char *auth_file);
 gboolean            gdm_server_start     (GdmServer   *server);
+#ifdef HAVE_PLYMOUTH
+gboolean            gdm_server_start_on_active_vt (GdmServer   *server);
+#endif
 gboolean            gdm_server_stop      (GdmServer   *server);
 char *              gdm_server_get_display_device (GdmServer *server);
 
diff --git a/daemon/gdm-simple-slave.c b/daemon/gdm-simple-slave.c
index fc8649c5..7c709a6e 100644
--- a/daemon/gdm-simple-slave.c
+++ b/daemon/gdm-simple-slave.c
@@ -93,6 +93,9 @@ struct GdmSimpleSlavePrivate
 #ifdef  HAVE_LOGINDEVPERM
         gboolean           use_logindevperm;
 #endif
+#ifdef  WITH_PLYMOUTH
+        guint              plymouth_is_running : 1;
+#endif
 };
 
 enum {
@@ -1204,6 +1207,74 @@ on_start_session_later (GdmGreeterServer *session,
         slave->priv->start_session_when_ready = FALSE;
 }
 
+#ifdef  WITH_PLYMOUTH
+static gboolean
+plymouth_is_running (void)
+{
+        int      status;
+        gboolean res;
+        GError  *error;
+
+        error = NULL;
+        res = g_spawn_command_line_sync ("/bin/plymouth --ping",
+                                         NULL, NULL, &status, &error);
+        if (! res) {
+                g_debug ("Could not ping plymouth: %s", error->message);
+                g_error_free (error);
+                return FALSE;
+        }
+
+        return WIFEXITED (status) && WEXITSTATUS (status) == 0;
+}
+
+static void
+plymouth_prepare_for_transition (GdmSimpleSlave *slave)
+{
+        gboolean res;
+        GError  *error;
+
+        error = NULL;
+        res = g_spawn_command_line_sync ("/bin/plymouth deactivate",
+                                         NULL, NULL, NULL, &error);
+        if (! res) {
+                g_warning ("Could not deactivate plymouth: %s", error->message);
+                g_error_free (error);
+        }
+}
+
+static void
+plymouth_quit_with_transition (GdmSimpleSlave *slave)
+{
+        gboolean res;
+        GError  *error;
+
+        error = NULL;
+        res = g_spawn_command_line_sync ("/bin/plymouth quit --retain-splash",
+                                         NULL, NULL, NULL, &error);
+        if (! res) {
+                g_warning ("Could not quit plymouth: %s", error->message);
+                g_error_free (error);
+        }
+        slave->priv->plymouth_is_running = FALSE;
+}
+
+static void
+plymouth_quit_without_transition (GdmSimpleSlave *slave)
+{
+        gboolean res;
+        GError  *error;
+
+        error = NULL;
+        res = g_spawn_command_line_sync ("/bin/plymouth quit",
+                                         NULL, NULL, NULL, &error);
+        if (! res) {
+                g_warning ("Could not quit plymouth: %s", error->message);
+                g_error_free (error);
+        }
+        slave->priv->plymouth_is_running = FALSE;
+}
+#endif
+
 static void
 setup_server (GdmSimpleSlave *slave)
 {
@@ -1223,6 +1294,12 @@ setup_server (GdmSimpleSlave *slave)
          */
         gdm_slave_save_root_windows (GDM_SLAVE (slave));
 
+#ifdef WITH_PLYMOUTH
+        /* Plymouth is waiting for the go-ahead to exit */
+        if (slave->priv->plymouth_is_running) {
+                plymouth_quit_with_transition (slave);
+        }
+#endif
 }
 
 static void
@@ -1426,6 +1503,12 @@ on_server_exited (GdmServer      *server,
         g_debug ("GdmSimpleSlave: server exited with code %d\n", exit_code);
 
         gdm_slave_stopped (GDM_SLAVE (slave));
+
+#ifdef WITH_PLYMOUTH
+        if (slave->priv->plymouth_is_running) {
+                plymouth_quit_without_transition (slave);
+        }
+#endif
 }
 
 static void
@@ -1438,6 +1521,12 @@ on_server_died (GdmServer      *server,
                  g_strsignal (signal_number));
 
         gdm_slave_stopped (GDM_SLAVE (slave));
+
+#ifdef WITH_PLYMOUTH
+        if (slave->priv->plymouth_is_running) {
+                plymouth_quit_without_transition (slave);
+        }
+#endif
 }
 
 static gboolean
@@ -1484,7 +1573,17 @@ gdm_simple_slave_run (GdmSimpleSlave *slave)
                                   G_CALLBACK (on_server_ready),
                                   slave);
 
-                res = gdm_server_start (slave->priv->server);
+#ifdef WITH_PLYMOUTH
+                slave->priv->plymouth_is_running = plymouth_is_running ();
+
+                if (slave->priv->plymouth_is_running) {
+                        plymouth_prepare_for_transition (slave);
+                        res = gdm_server_start_on_active_vt (slave->priv->server);
+                } else
+#endif
+                {
+                        res = gdm_server_start (slave->priv->server);
+                }
                 if (! res) {
                         g_warning (_("Could not start the X "
                                      "server (your graphical environment) "
@@ -1494,6 +1593,11 @@ gdm_simple_slave_run (GdmSimpleSlave *slave)
                                      "In the meantime this display will be "
                                      "disabled.  Please restart GDM when "
                                      "the problem is corrected."));
+#ifdef WITH_PLYMOUTH
+                        if (slave->priv->plymouth_is_running) {
+                                plymouth_quit_without_transition (slave);
+                        }
+#endif
                         exit (1);
                 }