+ int ret = 0;
+ size_t len;
+ FILE *fp;
+
+ /*
+ * boot_id needs to be read once before being used concurrently
+ * to deal with a Linux kernel race. A fix is proposed for
+ * upstream, but the work-around is needed for older kernels.
+ */
+ fp = fopen("/proc/sys/kernel/random/boot_id", "r");
+ if (!fp) {
+ return -ENOENT;
+ }
+ len = fread(uuid, 1, LTTNG_UST_UUID_STR_LEN - 1, fp);
+ if (len < LTTNG_UST_UUID_STR_LEN - 1) {
+ ret = -EINVAL;
+ goto end;
+ }
+ uuid[LTTNG_UST_UUID_STR_LEN - 1] = '\0';
+end:
+ fclose(fp);
+ return ret;