+
+ return r;
+}
+
+static int setup_one_tmp_dir(const char *id, const char *prefix, char **path) {
+ _cleanup_free_ char *x = NULL;
+ char bid[SD_ID128_STRING_MAX];
+ sd_id128_t boot_id;
+ int r;
+
+ assert(id);
+ assert(prefix);
+ assert(path);
+
+ /* We include the boot id in the directory so that after a
+ * reboot we can easily identify obsolete directories. */
+
+ r = sd_id128_get_boot(&boot_id);
+ if (r < 0)
+ return r;
+
+ x = strjoin(prefix, "/systemd-private-", sd_id128_to_string(boot_id, bid), "-", id, "-XXXXXX", NULL);
+ if (!x)
+ return -ENOMEM;
+
+ RUN_WITH_UMASK(0077)
+ if (!mkdtemp(x))
+ return -errno;
+
+ RUN_WITH_UMASK(0000) {
+ char *y;
+
+ y = strappenda(x, "/tmp");
+
+ if (mkdir(y, 0777 | S_ISVTX) < 0)
+ return -errno;
+ }
+
+ *path = x;
+ x = NULL;
+
+ return 0;
+}
+
+int setup_tmp_dirs(const char *id, char **tmp_dir, char **var_tmp_dir) {
+ char *a, *b;
+ int r;
+
+ assert(id);
+ assert(tmp_dir);
+ assert(var_tmp_dir);
+
+ r = setup_one_tmp_dir(id, "/tmp", &a);
+ if (r < 0)
+ return r;
+
+ r = setup_one_tmp_dir(id, "/var/tmp", &b);
+ if (r < 0) {
+ char *t;
+
+ t = strappenda(a, "/tmp");
+ rmdir(t);
+ rmdir(a);
+
+ free(a);
+ return r;
+ }
+
+ *tmp_dir = a;
+ *var_tmp_dir = b;
+
+ return 0;
+}
+
+int setup_netns(int netns_storage_socket[2]) {
+ _cleanup_close_ int netns = -1;
+ union {
+ struct cmsghdr cmsghdr;
+ uint8_t buf[CMSG_SPACE(sizeof(int))];
+ } control = {};
+ struct msghdr mh = {
+ .msg_control = &control,
+ .msg_controllen = sizeof(control),
+ };
+ struct cmsghdr *cmsg;
+ int r;
+
+ assert(netns_storage_socket);
+ assert(netns_storage_socket[0] >= 0);
+ assert(netns_storage_socket[1] >= 0);
+
+ /* We use the passed socketpair as a storage buffer for our
+ * namespace reference fd. Whatever process runs this first
+ * shall create a new namespace, all others should just join
+ * it. To serialize that we use a file lock on the socket
+ * pair.
+ *
+ * It's a bit crazy, but hey, works great! */
+
+ if (lockf(netns_storage_socket[0], F_LOCK, 0) < 0)
+ return -errno;
+
+ if (recvmsg(netns_storage_socket[0], &mh, MSG_DONTWAIT|MSG_CMSG_CLOEXEC) < 0) {
+ if (errno != EAGAIN) {
+ r = -errno;
+ goto fail;
+ }
+
+ /* Nothing stored yet, so let's create a new namespace */
+
+ if (unshare(CLONE_NEWNET) < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ loopback_setup();
+
+ netns = open("/proc/self/ns/net", O_RDONLY|O_CLOEXEC|O_NOCTTY);
+ if (netns < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ r = 1;
+ } else {
+ /* Yay, found something, so let's join the namespace */
+
+ for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
+ if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
+ assert(cmsg->cmsg_len == CMSG_LEN(sizeof(int)));
+ netns = *(int*) CMSG_DATA(cmsg);
+ }
+ }
+
+ if (setns(netns, CLONE_NEWNET) < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ r = 0;
+ }
+
+ cmsg = CMSG_FIRSTHDR(&mh);
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_RIGHTS;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+ memcpy(CMSG_DATA(cmsg), &netns, sizeof(int));
+ mh.msg_controllen = cmsg->cmsg_len;
+
+ if (sendmsg(netns_storage_socket[1], &mh, MSG_DONTWAIT|MSG_NOSIGNAL) < 0) {
+ r = -errno;
+ goto fail;