+_public_ int sd_pid_get_unit(pid_t pid, char **unit) {
+ int r;
+ char *cgroup, *p, *at, *b;
+ size_t k;
+
+ if (!unit)
+ return -EINVAL;
+
+ r = pid_get_cgroup(pid, NULL, &cgroup);
+ if (r < 0)
+ return r;
+
+ if (!startswith(cgroup, "/system/")) {
+ free(cgroup);
+ return -ENOENT;
+ }
+
+ p = cgroup + 8;
+ k = strcspn(p, "/");
+
+ at = memchr(p, '@', k);
+ if (at && at[1] == '.') {
+ size_t j;
+
+ /* This is a templated service */
+ if (p[k] != '/') {
+ free(cgroup);
+ return -EIO;
+ }
+
+ j = strcspn(p+k+1, "/");
+
+ b = malloc(k + j + 1);
+
+ if (b) {
+ memcpy(b, p, at - p + 1);
+ memcpy(b + (at - p) + 1, p + k + 1, j);
+ memcpy(b + (at - p) + 1 + j, at + 1, k - (at - p) - 1);
+ b[k+j] = 0;
+ }
+ } else
+ b = strndup(p, k);
+
+ free(cgroup);
+
+ if (!b)
+ return -ENOMEM;
+
+ *unit = b;
+ return 0;
+}
+