+_sd_hidden_ int sd_is_mq(int fd, const char *path) {
+#if !defined(__linux__)
+ return 0;
+#else
+ struct mq_attr attr;
+
+ if (fd < 0)
+ return -EINVAL;
+
+ if (mq_getattr(fd, &attr) < 0)
+ return -errno;
+
+ if (path) {
+ char fpath[PATH_MAX];
+ struct stat a, b;
+
+ if (path[0] != '/')
+ return -EINVAL;
+
+ if (fstat(fd, &a) < 0)
+ return -errno;
+
+ strncpy(stpcpy(fpath, "/dev/mqueue"), path, sizeof(fpath) - 12);
+ fpath[sizeof(fpath)-1] = 0;
+
+ if (stat(fpath, &b) < 0)
+ return -errno;
+
+ if (a.st_dev != b.st_dev ||
+ a.st_ino != b.st_ino)
+ return 0;
+ }
+
+ return 1;
+#endif
+}
+
+_sd_hidden_ int sd_notify(int unset_environment, const char *state) {