+
+void parse_user_at_host(char *arg, char **user, char **host) {
+ assert(arg);
+ assert(user);
+ assert(host);
+
+ *host = strchr(arg, '@');
+ if (*host == NULL)
+ *host = arg;
+ else {
+ *host[0]++ = '\0';
+ *user = arg;
+ }
+}
+
+int split_pair(const char *s, const char *sep, char **l, char **r) {
+ char *x, *a, *b;
+
+ assert(s);
+ assert(sep);
+ assert(l);
+ assert(r);
+
+ if (isempty(sep))
+ return -EINVAL;
+
+ x = strstr(s, sep);
+ if (!x)
+ return -EINVAL;
+
+ a = strndup(s, x - s);
+ if (!a)
+ return -ENOMEM;
+
+ b = strdup(x + strlen(sep));
+ if (!b) {
+ free(a);
+ return -ENOMEM;
+ }
+
+ *l = a;
+ *r = b;
+
+ return 0;
+}
+
+int shall_restore_state(void) {
+ _cleanup_free_ char *line;
+ char *w, *state;
+ size_t l;
+ int r;
+
+ r = proc_cmdline(&line);
+ if (r < 0)
+ return r;
+ if (r == 0) /* Container ... */
+ return 1;
+
+ FOREACH_WORD_QUOTED(w, l, line, state)
+ if (l == 23 && strneq(w, "systemd.restore_state=0", 23))
+ return 0;
+
+ return 1;
+}
+
+int proc_cmdline(char **ret) {
+ int r;
+
+ if (detect_container(NULL) > 0) {
+ char *buf, *p;
+ size_t sz = 0;
+
+ r = read_full_file("/proc/1/cmdline", &buf, &sz);
+ if (r < 0)
+ return r;
+
+ for (p = buf; p + 1 < buf + sz; p++)
+ if (*p == 0)
+ *p = ' ';
+
+ *p = 0;
+ *ret = buf;
+ return 1;
+ }
+
+ r = read_one_line_file("/proc/cmdline", ret);
+ if (r < 0)
+ return r;
+
+ return 1;
+}
+
+int container_get_leader(const char *machine, pid_t *pid) {
+ _cleanup_free_ char *s = NULL, *class = NULL;
+ const char *p;
+ pid_t leader;
+ int r;
+
+ assert(machine);
+ assert(pid);
+
+ p = strappenda("/run/systemd/machines/", machine);
+ r = parse_env_file(p, NEWLINE, "LEADER", &s, "CLASS", &class, NULL);
+ if (r == -ENOENT)
+ return -EHOSTDOWN;
+ if (r < 0)
+ return r;
+ if (!s)
+ return -EIO;
+
+ if (!streq_ptr(class, "container"))
+ return -EIO;
+
+ r = parse_pid(s, &leader);
+ if (r < 0)
+ return r;
+ if (leader <= 1)
+ return -EIO;
+
+ *pid = leader;
+ return 0;
+}
+
+int namespace_open(pid_t pid, int *pidns_fd, int *mntns_fd, int *root_fd) {
+ _cleanup_close_ int pidnsfd = -1, mntnsfd = -1;
+ const char *pidns, *mntns, *root;
+ int rfd;
+
+ assert(pid >= 0);
+ assert(pidns_fd);
+ assert(mntns_fd);
+ assert(root_fd);
+
+ mntns = procfs_file_alloca(pid, "ns/mnt");
+ mntnsfd = open(mntns, O_RDONLY|O_NOCTTY|O_CLOEXEC);
+ if (mntnsfd < 0)
+ return -errno;
+
+ pidns = procfs_file_alloca(pid, "ns/pid");
+ pidnsfd = open(pidns, O_RDONLY|O_NOCTTY|O_CLOEXEC);
+ if (pidnsfd < 0)
+ return -errno;
+
+ root = procfs_file_alloca(pid, "root");
+ rfd = open(root, O_RDONLY|O_NOCTTY|O_CLOEXEC|O_DIRECTORY);
+ if (rfd < 0)
+ return -errno;
+
+ *pidns_fd = pidnsfd;
+ *mntns_fd = mntnsfd;
+ *root_fd = rfd;
+ pidnsfd = -1;
+ mntnsfd = -1;
+
+ return 0;
+}
+
+int namespace_enter(int pidns_fd, int mntns_fd, int root_fd) {
+ assert(pidns_fd >= 0);
+ assert(mntns_fd >= 0);
+ assert(root_fd >= 0);
+
+ if (setns(pidns_fd, CLONE_NEWPID) < 0)
+ return -errno;
+
+ if (setns(mntns_fd, CLONE_NEWNS) < 0)
+ return -errno;
+
+ if (fchdir(root_fd) < 0)
+ return -errno;
+
+ if (chroot(".") < 0)
+ return -errno;
+
+ if (setresgid(0, 0, 0) < 0)
+ return -errno;
+
+ if (setresuid(0, 0, 0) < 0)
+ return -errno;
+
+ return 0;
+}
+
+bool pid_valid(pid_t pid) {
+ if (pid <= 0)
+ return false;
+
+ if (kill(pid, 0) >= 0)
+ return true;
+
+ return errno != ESRCH;
+}
+
+int getpeercred(int fd, struct ucred *ucred) {
+ socklen_t n = sizeof(struct ucred);
+ struct ucred u;
+ int r;
+
+ assert(fd >= 0);
+ assert(ucred);
+
+ r = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &u, &n);
+ if (r < 0)
+ return -errno;
+
+ if (n != sizeof(struct ucred))
+ return -EIO;
+
+ /* Check if the data is actually useful and not suppressed due
+ * to namespacing issues */
+ if (u.pid <= 0)
+ return -ENODATA;
+
+ *ucred = u;
+ return 0;
+}
+
+int getpeersec(int fd, char **ret) {
+ socklen_t n = 64;
+ char *s;
+ int r;
+
+ assert(fd >= 0);
+ assert(ret);
+
+ s = new0(char, n);
+ if (!s)
+ return -ENOMEM;
+
+ r = getsockopt(fd, SOL_SOCKET, SO_PEERSEC, s, &n);
+ if (r < 0) {
+ free(s);
+
+ if (errno != ERANGE)
+ return -errno;
+
+ s = new0(char, n);
+ if (!s)
+ return -ENOMEM;
+
+ r = getsockopt(fd, SOL_SOCKET, SO_PEERSEC, s, &n);
+ if (r < 0) {
+ free(s);
+ return -errno;
+ }
+ }
+
+ if (isempty(s)) {
+ free(s);
+ return -ENOTSUP;
+ }
+
+ *ret = s;
+ return 0;
+}