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 BT_HIDDEN
  20 void bt_uuid_generate(bt_uuid_t uuid_out)
  21 {
  22         int i;
  23         GRand *rand;
  24
  25         BT_ASSERT(uuid_out);
  26
  27         rand = g_rand_new();
  28
  29         /*
  30          * Generate 16 bytes of random bits.
  31          */
  32         for (i = 0; i < BT_UUID_LEN; i++) {
  33                 uuid_out[i] = (uint8_t) g_rand_int(rand);
  34         }
  35
  36         /*
  37          * Set the two most significant bits (bits 6 and 7) of the
  38          * clock_seq_hi_and_reserved to zero and one, respectively.
  39          */
  40         uuid_out[8] &= ~(1 << 6);
  41         uuid_out[8] |= (1 << 7);
  42
  43         /*
  44          * Set the four most significant bits (bits 12 through 15) of the
  45          * time_hi_and_version field to the 4-bit version number from
  46          * Section 4.1.3.
  47          */
  48         uuid_out[6] &= 0x0f;
  49         uuid_out[6] |= (BT_UUID_VER << 4);
  50
  51         g_rand_free(rand);
  52 }
  53
  54 BT_HIDDEN
  55 void bt_uuid_to_str(const bt_uuid_t uuid_in, char *str_out)
  56 {
  57         BT_ASSERT_DBG(uuid_in);
  58         BT_ASSERT_DBG(str_out);
  59
  60         sprintf(str_out, BT_UUID_FMT, BT_UUID_FMT_VALUES(uuid_in));
  61 }
  62
  63 BT_HIDDEN
  64 int bt_uuid_from_str(const char *str_in, bt_uuid_t uuid_out)
  65 {
  66         int ret = 0;
  67         bt_uuid_t uuid_scan;
  68
  69         BT_ASSERT_DBG(uuid_out);
  70         BT_ASSERT_DBG(str_in);
  71
  72         if (strnlen(str_in, BT_UUID_STR_LEN + 1) != BT_UUID_STR_LEN) {
  73                 ret = -1;
  74                 goto end;
  75         }
  76
  77         /* Scan to a temporary location in case of a partial match. */
  78         if (sscanf(str_in, BT_UUID_FMT, BT_UUID_SCAN_VALUES(uuid_scan)) != BT_UUID_LEN) {
  79                 ret = -1;
  80         }
  81
  82         bt_uuid_copy(uuid_out, uuid_scan);
  83 end:
  84         return ret;
  85 }
  86
  87 BT_HIDDEN
  88 int bt_uuid_compare(const bt_uuid_t uuid_a, const bt_uuid_t uuid_b)
  89 {
  90         return memcmp(uuid_a, uuid_b, BT_UUID_LEN);
  91 }
  92
  93 BT_HIDDEN
  94 void bt_uuid_copy(bt_uuid_t uuid_dest, const bt_uuid_t uuid_src)
  95 {
  96         BT_ASSERT(uuid_dest);
  97         BT_ASSERT(uuid_src);
  98         BT_ASSERT(uuid_dest != uuid_src);
  99
 100         memcpy(uuid_dest, uuid_src, BT_UUID_LEN);
 101 }