zdtm/unix: add zero characters into a socket address

An abstract name can contain zero characters.
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

test/zdtm/static/sk-unix-unconn.c

@@ -12,7 +12,7 @@ const char *test_author	= "Vagin Andrew <avagin@parallels.com>";
 int main(int argc, char ** argv)
 {
 	int sk, skc;
-	int ret;
+	int ret, len;
 	char path[PATH_MAX];
 	struct sockaddr_un addr;
 	socklen_t addrlen;
@@ -31,12 +31,13 @@ int main(int argc, char ** argv)
 		return 1;
 	}
 
-	snprintf(path, sizeof(path), "X/zdtm-%s-%d", argv[0], getpid());
+	len = snprintf(path, sizeof(path), "X/zdtm-%s-%d/X", argv[0], getpid());
 
 	addr.sun_family = AF_UNIX;
 	strncpy(addr.sun_path, path, sizeof(addr.sun_path));
-	addrlen = sizeof(addr.sun_family) + strlen(path);
+	addrlen = sizeof(addr.sun_family) + len;
 	addr.sun_path[0] = 0;
+	addr.sun_path[len - 1] = 0;
 
 	ret = bind(sk, (struct sockaddr *) &addr, addrlen);
 	if (ret) {