[Libguestfs] [PATCH] launch: libvirt: Better error when bridge / virbr0 doesn't exist (RHBZ#1262127).
The current diagnostic is terrible. This one tells the user how to
diagnose and fix the problem.
---
src/launch-libvirt.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 47 insertions(+)
diff --git a/src/launch-libvirt.c b/src/launch-libvirt.c
index 1c0bfac..d4c4c47 100644
--- a/src/launch-libvirt.c
+++ b/src/launch-libvirt.c
@@ -181,6 +181,7 @@ static int is_blk (const char *path);
static void ignore_errors (void *ignore, virErrorPtr ignore2);
static void set_socket_create_context (guestfs_h *g);
static void clear_socket_create_context (guestfs_h *g);
+static int check_bridge_exists (guestfs_h *g, const char *brname);
#if HAVE_LIBSELINUX
static void selinux_warning (guestfs_h *g, const char *func, const char *selinux_op,
const char *data);
@@ -393,6 +394,9 @@ launch_libvirt (guestfs_h *g, void *datav, const char *libvirt_uri)
}
guestfs_pop_error_handler (g);
+ if (g->enable_network && check_bridge_exists (g, data->network_bridge) ==
-1)
+ goto cleanup;
+
/* Locate and/or build the appliance. */
TRACE0 (launch_build_libvirt_appliance_start);
@@ -1988,6 +1992,49 @@ is_blk (const char *path)
return S_ISBLK (statbuf.st_mode);
}
+static int
+is_dir (const char *path)
+{
+ struct stat statbuf;
+
+ if (stat (path, &statbuf) == -1)
+ return 0;
+ return S_ISDIR (statbuf.st_mode);
+}
+
+/* Used to check the network_bridge exists, or give a useful error
+ * message.
+ */
+static int
+check_bridge_exists (guestfs_h *g, const char *brname)
+{
+ CLEANUP_FREE char *path = NULL;
+
+ /* If this doesn't look like Linux, give up. */
+ if (!is_dir ("/sys/class/net"))
+ return 0;
+
+ /* Does the interface exist and is it a bridge? */
+ path = safe_asprintf (g, "/sys/class/net/%s/bridge", brname);
+ if (is_dir (path))
+ return 0;
+
+ error (g,
+ _("bridge '%s' not found. Try running:\n"
+ "\n"
+ " brctl show\n"
+ "\n"
+ "to get a list of bridges on the host, and then selecting the\n"
+ "bridge you wish the appliance network to connect to using:\n"
+ "\n"
+ " export LIBGUESTFS_BACKEND_SETTINGS=network_bridge=<bridge
name>\n"
+ "\n"
+ "You may also need to allow the bridge in /etc/qemu/bridge.conf.\n"
+ "For further information see guestfs(3)."),
+ brname);
+ return -1;
+}
+
static void
ignore_errors (void *ignore, virErrorPtr ignore2)
{
--
2.5.0