Fix: sessiond: instance uuid is not sufficiently unique

[lttng-tools.git] / src / common / uuid.c

diff --git a/src/common/uuid.c b/src/common/uuid.c
index 68fddc0a2ff0089376275b8db80064ad734bc880..0e01c2185cc819327066dab0b9580059432d2d97 100644 (file)
--- a/src/common/uuid.c
+++ b/src/common/uuid.c
@@ -2,20 +2,14 @@
  * Copyright (C) 2018 Jérémie Galarneau <jeremie.galarneau@efficios.com>
  * Copyright (C) 2019 Michael Jeanson <mjeanson@efficios.com>
  *
- * This library is free software; you can redistribute it and/or modify it
- * under the terms of the GNU Lesser General Public License, version 2.1 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: LGPL-2.1-only
  *
- * This library is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
- * for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this library; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include <common/compat/string.h>
+#include <common/random.h>
+#include <common/error.h>
+
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -43,7 +37,7 @@ int lttng_uuid_from_str(const char *str_in, lttng_uuid uuid_out)
                goto end;
        }
 
-       if (strnlen(str_in, LTTNG_UUID_STR_LEN) != LTTNG_UUID_STR_LEN - 1) {
+       if (lttng_strnlen(str_in, LTTNG_UUID_STR_LEN) != LTTNG_UUID_STR_LEN - 1) {
                ret = -1;
                goto end;
        }
@@ -87,18 +81,15 @@ int lttng_uuid_generate(lttng_uuid uuid_out)
        }
 
        if (!lttng_uuid_is_init) {
-               /*
-                * We don't need cryptographic quality randomness to
-                * generate UUIDs, seed rand with the epoch.
-                */
-               const time_t epoch = time(NULL);
-
-               if (epoch == (time_t) -1) {
-                       ret = -1;
+               seed_t new_seed;
+
+               ret = lttng_produce_best_effort_random_seed(&new_seed);
+               if (ret) {
+                       ERR("Failed to initialize random seed while generating UUID");
                        goto end;
                }
-               srand(epoch);
 
+               srand(new_seed);
                lttng_uuid_is_init = true;
        }