common: compile libcommon as C++

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

diff --git a/src/common/uuid.cpp b/src/common/uuid.cpp
new file mode 100644 (file)
index 0000000..77b9a76
--- /dev/null
+++ b/src/common/uuid.cpp
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2018 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ * Copyright (C) 2019 Michael Jeanson <mjeanson@efficios.com>
+ *
+ * SPDX-License-Identifier: LGPL-2.1-only
+ *
+ */
+
+#include <common/compat/string.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include "uuid.h"
+
+static const lttng_uuid nil_uuid = { 0 };
+static bool lttng_uuid_is_init;
+
+void lttng_uuid_to_str(const lttng_uuid uuid, char *uuid_str)
+{
+       sprintf(uuid_str, LTTNG_UUID_FMT, LTTNG_UUID_FMT_VALUES(uuid));
+}
+
+int lttng_uuid_from_str(const char *str_in, lttng_uuid uuid_out)
+{
+       int ret = 0;
+       lttng_uuid uuid_scan;
+
+       if ((str_in == NULL) || (uuid_out == NULL)) {
+               ret = -1;
+               goto end;
+       }
+
+       if (lttng_strnlen(str_in, LTTNG_UUID_STR_LEN) != LTTNG_UUID_STR_LEN - 1) {
+               ret = -1;
+               goto end;
+       }
+
+       /* Scan to a temporary location in case of a partial match. */
+       if (sscanf(str_in, LTTNG_UUID_FMT, LTTNG_UUID_SCAN_VALUES(uuid_scan)) !=
+                       LTTNG_UUID_LEN) {
+               ret = -1;
+       }
+
+       lttng_uuid_copy(uuid_out, uuid_scan);
+end:
+       return ret;
+}
+
+bool lttng_uuid_is_equal(const lttng_uuid a, const lttng_uuid b)
+{
+       return memcmp(a, b, LTTNG_UUID_LEN) == 0;
+}
+
+bool lttng_uuid_is_nil(const lttng_uuid uuid)
+{
+       return memcmp(nil_uuid, uuid, sizeof(lttng_uuid)) == 0;
+}
+
+void lttng_uuid_copy(lttng_uuid dst, const lttng_uuid src)
+{
+       memcpy(dst, src, LTTNG_UUID_LEN);
+}
+
+/*
+ * Generate a random UUID according to RFC4122, section 4.4.
+ */
+int lttng_uuid_generate(lttng_uuid uuid_out)
+{
+       int i, ret = 0;
+
+       if (uuid_out == NULL) {
+               ret = -1;
+               goto end;
+       }
+
+       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;
+                       goto end;
+               }
+               srand(epoch);
+
+               lttng_uuid_is_init = true;
+       }
+
+       /*
+        * Generate 16 bytes of random bits.
+        */
+       for (i = 0; i < LTTNG_UUID_LEN; i++) {
+               uuid_out[i] = (uint8_t) rand();
+       }
+
+       /*
+        * Set the two most significant bits (bits 6 and 7) of the
+        * clock_seq_hi_and_reserved to zero and one, respectively.
+        */
+       uuid_out[8] &= ~(1 << 6);
+       uuid_out[8] |= (1 << 7);
+
+       /*
+        * Set the four most significant bits (bits 12 through 15) of the
+        * time_hi_and_version field to the 4-bit version number from
+        * Section 4.1.3.
+        */
+       uuid_out[6] &= 0x0f;
+       uuid_out[6] |= (LTTNG_UUID_VER << 4);
+
+end:
+       return ret;
+}