[gnome-settings-daemon] power: Allow overriding the VM detection

[Bastien Nocera <hadess src gnome org>]

commit 6dde03d8d4b12e9cc3dd507345a3420a24567ef7
Author: Bastien Nocera <hadess hadess net>
Date:   Mon Jan 14 10:09:43 2013 +0100

    power: Allow overriding the VM detection
    
    In some cases we want the power plugin running in a virtual machine
    to behave as it would on bare metal. The gnome.is_vm=[01] kernel
    command-line argument allows us to override the detection that
    would be done through systemd.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=688759

 plugins/power/gsd-power-manager.c |   42 +++++++++++++++++++++++++++++++++++++
 1 files changed, 42 insertions(+), 0 deletions(-)
---
diff --git a/plugins/power/gsd-power-manager.c b/plugins/power/gsd-power-manager.c
index 7295df5..ee22385 100644
--- a/plugins/power/gsd-power-manager.c
+++ b/plugins/power/gsd-power-manager.c
@@ -3955,6 +3955,45 @@ logind_proxy_signal_cb (GDBusProxy  *proxy,
 }
 
 static gboolean
+parse_vm_kernel_cmdline (gboolean *is_virtual_machine)
+{
+        gboolean ret = FALSE;
+        GRegex *regex;
+        GMatchInfo *match;
+        char *contents;
+        char *word;
+        const char *arg;
+
+        if (!g_file_get_contents ("/proc/cmdline", &contents, NULL, NULL))
+                return ret;
+
+        regex = g_regex_new ("gnome.is_vm=(\\S+)", 0, G_REGEX_MATCH_NOTEMPTY, NULL);
+        if (!g_regex_match (regex, contents, G_REGEX_MATCH_NOTEMPTY, &match))
+                goto out;
+
+        word = g_match_info_fetch (match, 0);
+        g_debug ("Found command-line match '%s'", word);
+        arg = word + strlen ("gnome.is_vm=");
+        if (*arg != '0' && *arg != '1') {
+                g_warning ("Invalid value '%s' for gnome.is_vm passed in kernel command line.\n", arg);
+        } else {
+                *is_virtual_machine = atoi (arg);
+                ret = TRUE;
+        }
+        g_free (word);
+
+out:
+        g_match_info_free (match);
+        g_regex_unref (regex);
+        g_free (contents);
+
+        if (ret)
+                g_debug ("Kernel command-line parsed to %d", *is_virtual_machine);
+
+        return ret;
+}
+
+static gboolean
 is_hardware_a_virtual_machine (void)
 {
         const gchar *str;
@@ -3964,6 +4003,9 @@ is_hardware_a_virtual_machine (void)
         GVariant *variant = NULL;
         GDBusConnection *connection;
 
+        if (parse_vm_kernel_cmdline (&ret))
+                return ret;
+
         connection = g_bus_get_sync (G_BUS_TYPE_SYSTEM,
                                      NULL,
                                      &error);