[gnome-boxes] util: Better check for bridge network availability

[Zeeshan Ali Khattak <zeeshanak src gnome org>]

commit 69e5ef4a2904220fa80ffd5be9360e7f8e907b12
Author: Zeeshan Ali (Khattak) <zeeshanak gnome org>
Date:   Fri Dec 13 14:04:37 2013 +0000

    util: Better check for bridge network availability
    
    Instead of trying to connect to system libvirt to check if its running,
    lets just check if "virbr0" is up or not.

 src/Makefile.am   |    1 +
 src/util-app.vala |   23 ++++++++++++++++++++---
 2 files changed, 21 insertions(+), 3 deletions(-)
---
diff --git a/src/Makefile.am b/src/Makefile.am
index cbfec97..da1d380 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -35,6 +35,7 @@ AM_VALAFLAGS =                                                \
        --pkg libvirt-gobject-1.0                       \
        --pkg libxml-2.0                                \
        --pkg posix                                     \
+       --pkg linux                                     \
        --pkg spice-client-gtk-3.0                      \
        --pkg tracker-sparql-$(TRACKER_VERSION)         \
        $(VALA_DEBUG_FLAGS)                             \
diff --git a/src/util-app.vala b/src/util-app.vala
index 616442d..f4e2b54 100644
--- a/src/util-app.vala
+++ b/src/util-app.vala
@@ -1,6 +1,7 @@
 // This file is part of GNOME Boxes. License: LGPLv2+
 using Gtk;
 using Xml;
+using Linux;
 
 namespace Boxes {
 
@@ -244,11 +245,27 @@ namespace Boxes {
         if (libvirt_bridge_net_checked)
             return libvirt_bridge_net_available;
 
-        var connection = new GVir.Connection ("qemu:///system");
-
         try {
-            connection.open_read_only ();
+            // First check if bridge interface is up
+            var sock = Posix.socket (Posix.AF_INET, Posix.SOCK_STREAM, 0);
+            if (sock < 0)
+                throw (GLib.IOError) new GLib.Error (G_IO_ERROR,
+                                                     g_io_error_from_errno (Posix.errno),
+                                                     "Failed to create a socket");
+
+            var req = Network.IfReq ();
+            var if_name = "virbr0";
+            for (var i = 0; i <= if_name.length;  i++)
+                req.ifr_name[i] = (char) if_name[i];
+
+            if (Posix.ioctl (sock, Network.SIOCGIFFLAGS, ref req) < 0 ||
+                !(Network.IfFlag.UP in req.ifr_flags)) {
+                debug ("Interface '%s' is either not available or not up.", if_name);
+
+                return false;
+            }
 
+            // Now check if unprivileged qemu is allowed to access it
             var file = File.new_for_path ("/etc/qemu/bridge.conf");
             uint8[] contents;
             file.load_contents (null, out contents, null);