X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fuuid.cpp;fp=src%2Fcommon%2Fuuid.cpp;h=77b9a767bececffe3210255c9d8c11f1dc9a086d;hp=0000000000000000000000000000000000000000;hb=a6bc4ca9d659caf016ef932fcd944029737ac57c;hpb=97535efaa975ca52bf02c2d5e76351bfd2e3defa

diff --git a/src/common/uuid.cpp b/src/common/uuid.cpp
new file mode 100644
index 000000000..77b9a767b
--- /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;
+}