-char* specifier_string(char specifier, void *data, void *userdata) {
- return strdup(strempty(data));
+int specifier_string(char specifier, void *data, void *userdata, char **ret) {
+ char *n;
+
+ n = strdup(strempty(data));
+ if (!n)
+ return -ENOMEM;
+
+ *ret = n;
+ return 0;
+}
+
+int specifier_machine_id(char specifier, void *data, void *userdata, char **ret) {
+ sd_id128_t id;
+ char *n;
+ int r;
+
+ r = sd_id128_get_machine(&id);
+ if (r < 0)
+ return r;
+
+ n = new(char, 33);
+ if (!n)
+ return -ENOMEM;
+
+ *ret = sd_id128_to_string(id, n);
+ return 0;
+}
+
+int specifier_boot_id(char specifier, void *data, void *userdata, char **ret) {
+ sd_id128_t id;
+ char *n;
+ int r;
+
+ r = sd_id128_get_boot(&id);
+ if (r < 0)
+ return r;
+
+ n = new(char, 33);
+ if (!n)
+ return -ENOMEM;
+
+ *ret = sd_id128_to_string(id, n);
+ return 0;
+}
+
+int specifier_host_name(char specifier, void *data, void *userdata, char **ret) {
+ char *n;
+
+ n = gethostname_malloc();
+ if (!n)
+ return -ENOMEM;
+
+ *ret = n;
+ return 0;
+}
+
+int specifier_kernel_release(char specifier, void *data, void *userdata, char **ret) {
+ struct utsname uts;
+ char *n;
+ int r;
+
+ r = uname(&uts);
+ if (r < 0)
+ return -errno;
+
+ n = strdup(uts.release);
+ if (!n)
+ return -ENOMEM;
+
+ *ret = n;
+ return 0;