tests: add a test for c/r of an empty bridge

v2: * add a zdtm.py .desc file
    * only look to make sure inet addresses match (in particular, don't
      match the state)
Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm.sh

@@ -200,6 +200,7 @@ generate_test_list()
 		ns/static/sem
 		transition/ipc
 		ns/static/netns-dev
+		static/bridge
 		static/cgroup00
 		static/cgroup01
 		static/cgroup02
@@ -361,6 +362,7 @@ different_creds
 inotify01
 ipc_namespace
 utsname
+bridge
 "
 
 TEST_EXPECTED_FAILURE="

test/zdtm/.gitignore

@@ -2,6 +2,7 @@
 /live/static/apparmor
 /live/static/arm-neon00
 /live/static/bind-mount
+/live/static/bridge
 /live/static/busyloop00
 /live/static/caps00
 /live/static/cgroup00

test/zdtm/live/static/Makefile

@@ -130,6 +130,7 @@ TST_NOFILE	=				\
 		seccomp_strict			\
 		different_creds			\
 		vsx				\
+		bridge				\
 #		jobctl00			\
 
 TST_FILE	=				\

test/zdtm/live/static/bridge.c

+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/mount.h>
+#include <linux/limits.h>
+#include <signal.h>
+#include "zdtmtst.h"
+
+const char *test_doc	= "check that empty bridges are c/r'd correctly";
+const char *test_author	= "Tycho Andersen <tycho.andersen@canonical.com>";
+
+#define BRIDGE_NAME "zdtmbr0"
+
+int add_bridge(void)
+{
+	if (system("brctl addbr " BRIDGE_NAME))
+		return -1;
+
+	if (system("ifconfig " BRIDGE_NAME " 10.0.55.55"))
+		return -1;
+
+	if (system("ifconfig " BRIDGE_NAME " up"))
+		return -1;
+
+	return 0;
+}
+
+int del_bridge(void)
+{
+	/* don't check for errors, let's try to make sure it's deleted */
+	system("ifconfig " BRIDGE_NAME " down");
+
+	if (system("brctl delbr " BRIDGE_NAME))
+		return -1;
+
+	return 0;
+}
+
+int main(int argc, char **argv)
+{
+	int ret = 1;
+	test_init(argc, argv);
+
+	if (add_bridge() < 0)
+		return 1;
+
+	/* Here, we grep for inet because some of the IPV6 DAD stuff can be
+	 * racy, and all we really care about is that the bridge got restored
+	 * with the right MAC, since we know DAD will succeed eventually.
+	 *
+	 * (I got this race with zdtm.py, but not with zdtm.sh; not quite sure
+	 * what the environment difference is/was.)
+	 */
+	if (system("ip addr list dev " BRIDGE_NAME " | grep inet > bridge.dump.test")) {
+		pr_perror("can't save net config");
+		fail("Can't save net config");
+		goto out;
+	}
+
+	test_daemon();
+	test_waitsig();
+
+	if (system("ip addr list dev " BRIDGE_NAME " | grep inet > bridge.rst.test")) {
+		fail("Can't get net config");
+		goto out;
+	}
+
+	if (system("diff bridge.rst.test bridge.dump.test")) {
+		fail("Net config differs after restore");
+		goto out;
+	}
+
+	pass();
+
+	ret = 0;
+
+out:
+	del_bridge();
+	return ret;
+}

test/zdtm/live/static/bridge.desc

+{'flavor': 'ns uns', 'deps': [ '/bin/sh', '/bin/grep', '/sbin/ip', '/sbin/brctl', '/sbin/ifconfig', '/usr/bin/diff'], 'flags': 'suid'}