Load all users only when really needed

[sojka/lightdm.git] / src / vt.c

diff --git a/src/vt.c b/src/vt.c
index c2b1c0d662f005ae5b6031e8c2909ed74c887fd4..d784a8c83174d4bd894e378f94f4fc279a45dc26 100644 (file)
--- a/src/vt.c
+++ b/src/vt.c
@@ -1,7 +1,7 @@
 /*
  * Copyright (C) 2010-2011 Robert Ancell.
  * Author: Robert Ancell <robert.ancell@canonical.com>
- * 
+ *
  * 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 3 of the License, or (at your option) any later
@@ -26,36 +26,46 @@
 static GList *used_vts = NULL;
 
 static gint
-open_console (void)
+open_tty (void)
 {
     int fd;
 
-    fd = g_open ("/dev/console", O_RDONLY | O_NOCTTY, 0);
+    fd = g_open ("/dev/tty0", O_RDONLY | O_NOCTTY, 0);
     if (fd < 0)
-        g_warning ("Error opening /dev/console: %s", strerror (errno));
+        g_warning ("Error opening /dev/tty0: %s", strerror (errno));
     return fd;
 }
 
+gboolean
+vt_can_multi_seat (void)
+{
+    /* Quick check to see if we can multi seat.  This is intentionally the
+       same check logind does, just without actually reading from the files.
+       Existence will prove whether we have CONFIG_VT built into the kernel. */
+    return access ("/dev/tty0", F_OK) == 0 &&
+           access ("/sys/class/tty/tty0/active", F_OK) == 0;
+}
+
 gint
 vt_get_active (void)
 {
 #ifdef __linux__
-    gint console_fd;
+    gint tty_fd;
     gint active = -1;
 
     /* Pretend always active */
     if (getuid () != 0)
         return 1;
 
-    console_fd = open_console ();
-    if (console_fd >= 0)
+    tty_fd = open_tty ();
+    if (tty_fd >= 0)
     {
-        struct vt_stat console_state = { 0 };
-        if (ioctl (console_fd, VT_GETSTATE, &console_state) < 0)
-            g_warning ("Error using VT_GETSTATE on /dev/console: %s", strerror (errno));
+        struct vt_stat vt_state = { 0 };
+        if (ioctl (tty_fd, VT_GETSTATE, &vt_state) < 0)
+            g_warning ("Error using VT_GETSTATE on /dev/tty0: %s", strerror (errno));
         else
-            active = console_state.v_active;
-        close (console_fd);
+            active = vt_state.v_active;
+        close (tty_fd);
     }
 
     return active;
@@ -68,29 +78,33 @@ void
 vt_set_active (gint number)
 {
 #ifdef __linux__
-    gint console_fd;
+    gint tty_fd;
 
     g_debug ("Activating VT %d", number);
 
     /* Pretend always active */
     if (getuid () != 0)
-        return;   
+        return;
 
-    console_fd = open_console ();
-    if (console_fd >= 0)
+    tty_fd = open_tty ();
+    if (tty_fd >= 0)
     {
         int n = number;
 
-        if (ioctl (console_fd, VT_ACTIVATE, n) < 0)
-            g_warning ("Error using VT_ACTIVATE %d on /dev/console: %s", n, strerror (errno));
+        if (ioctl (tty_fd, VT_ACTIVATE, n) < 0)
+        {
+            g_warning ("Error using VT_ACTIVATE %d on /dev/tty0: %s", n, strerror (errno));
+            close (tty_fd);
+            return;
+        }
 
         /* Wait for the VT to become active to avoid a suspected
          * race condition somewhere between LightDM, X, ConsoleKit and the kernel.
          * See https://bugs.launchpad.net/bugs/851612 */
-        if (ioctl (console_fd, VT_WAITACTIVE) < 0)
-            g_warning ("Error using VT_WAITACTIVE %d on /dev/console: %s", n, strerror (errno));
+        if (ioctl (tty_fd, VT_WAITACTIVE, n) < 0)
+            g_warning ("Error using VT_WAITACTIVE %d on /dev/tty0: %s", n, strerror (errno));
 
-        close (console_fd);
+        close (tty_fd);
     }
 #endif
 }
@@ -133,7 +147,7 @@ vt_get_unused (void)
     number = vt_get_min ();
     while (vt_is_used (number))
         number++;
- 
+
     return number;
 }
 
@@ -141,7 +155,7 @@ void
 vt_ref (gint number)
 {
     g_debug ("Using VT %d", number);
-    used_vts = g_list_append (used_vts, GINT_TO_POINTER (number)); 
+    used_vts = g_list_append (used_vts, GINT_TO_POINTER (number));
 }
 
 void