Re: [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; +} +