src/common/uuid.c

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright (C) 2019 Michael Jeanson <mjeanson@efficios.com>
   5  */
   6
   7 #include <glib.h>
   8 #include <stdio.h>
   9 #include <string.h>
  10 #include <inttypes.h>
  11
  12 #include "common/assert.h"
  13 #include "common/uuid.h"
  14
  15
  16 /*
  17  * Generate a random UUID according to RFC4122, section 4.4.
  18  */
  19 void bt_uuid_generate(bt_uuid_t uuid_out)
  20 {
  21         int i;
  22         GRand *rand;
  23
  24         BT_ASSERT(uuid_out);
  25
  26         rand = g_rand_new();
  27
  28         /*
  29          * Generate 16 bytes of random bits.
  30          */
  31         for (i = 0; i < BT_UUID_LEN; i++) {
  32                 uuid_out[i] = (uint8_t) g_rand_int(rand);
  33         }
  34
  35         /*
  36          * Set the two most significant bits (bits 6 and 7) of the
  37          * clock_seq_hi_and_reserved to zero and one, respectively.
  38          */
  39         uuid_out[8] &= ~(1 << 6);
  40         uuid_out[8] |= (1 << 7);
  41
  42         /*
  43          * Set the four most significant bits (bits 12 through 15) of the
  44          * time_hi_and_version field to the 4-bit version number from
  45          * Section 4.1.3.
  46          */
  47         uuid_out[6] &= 0x0f;
  48         uuid_out[6] |= (BT_UUID_VER << 4);
  49
  50         g_rand_free(rand);
  51 }
  52
  53 void bt_uuid_to_str(const bt_uuid_t uuid_in, char *str_out)
  54 {
  55         BT_ASSERT_DBG(uuid_in);
  56         BT_ASSERT_DBG(str_out);
  57
  58         snprintf(str_out, BT_UUID_STR_LEN + 1, BT_UUID_FMT, BT_UUID_FMT_VALUES(uuid_in));
  59 }
  60
  61 int bt_uuid_from_str(const char *str_in, bt_uuid_t uuid_out)
  62 {
  63         int ret = 0;
  64         bt_uuid_t uuid_scan;
  65
  66         BT_ASSERT_DBG(uuid_out);
  67         BT_ASSERT_DBG(str_in);
  68
  69         if (strnlen(str_in, BT_UUID_STR_LEN + 1) != BT_UUID_STR_LEN) {
  70                 ret = -1;
  71                 goto end;
  72         }
  73
  74         /* Scan to a temporary location in case of a partial match. */
  75         if (sscanf(str_in, BT_UUID_FMT, BT_UUID_SCAN_VALUES(uuid_scan)) != BT_UUID_LEN) {
  76                 ret = -1;
  77         }
  78
  79         bt_uuid_copy(uuid_out, uuid_scan);
  80 end:
  81         return ret;
  82 }
  83
  84 int bt_uuid_compare(const bt_uuid_t uuid_a, const bt_uuid_t uuid_b)
  85 {
  86         return memcmp(uuid_a, uuid_b, BT_UUID_LEN);
  87 }
  88
  89 void bt_uuid_copy(bt_uuid_t uuid_dest, const bt_uuid_t uuid_src)
  90 {
  91         BT_ASSERT(uuid_dest);
  92         BT_ASSERT(uuid_src);
  93         BT_ASSERT(uuid_dest != uuid_src);
  94
  95         memcpy(uuid_dest, uuid_src, BT_UUID_LEN);
  96 }