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c70636a7 MJ |
1 | /* |
2 | * Copyright (C) 2018 Jérémie Galarneau <jeremie.galarneau@efficios.com> | |
3 | * Copyright (C) 2019 Michael Jeanson <mjeanson@efficios.com> | |
4 | * | |
ab5be9fa | 5 | * SPDX-License-Identifier: LGPL-2.1-only |
c70636a7 | 6 | * |
c70636a7 MJ |
7 | */ |
8 | ||
a1298db6 | 9 | #include <common/compat/string.h> |
c70636a7 MJ |
10 | #include <stddef.h> |
11 | #include <stdint.h> | |
12 | #include <stdio.h> | |
13 | #include <stdlib.h> | |
14 | #include <string.h> | |
15 | #include <time.h> | |
16 | ||
17 | #include "uuid.h" | |
18 | ||
19 | static const lttng_uuid nil_uuid; | |
20 | static bool lttng_uuid_is_init; | |
21 | ||
22 | void lttng_uuid_to_str(const lttng_uuid uuid, char *uuid_str) | |
23 | { | |
24 | sprintf(uuid_str, LTTNG_UUID_FMT, LTTNG_UUID_FMT_VALUES(uuid)); | |
25 | } | |
26 | ||
27 | int lttng_uuid_from_str(const char *str_in, lttng_uuid uuid_out) | |
28 | { | |
29 | int ret = 0; | |
30 | lttng_uuid uuid_scan; | |
31 | ||
32 | if ((str_in == NULL) || (uuid_out == NULL)) { | |
33 | ret = -1; | |
34 | goto end; | |
35 | } | |
36 | ||
a1298db6 | 37 | if (lttng_strnlen(str_in, LTTNG_UUID_STR_LEN) != LTTNG_UUID_STR_LEN - 1) { |
c70636a7 MJ |
38 | ret = -1; |
39 | goto end; | |
40 | } | |
41 | ||
42 | /* Scan to a temporary location in case of a partial match. */ | |
43 | if (sscanf(str_in, LTTNG_UUID_FMT, LTTNG_UUID_SCAN_VALUES(uuid_scan)) != | |
44 | LTTNG_UUID_LEN) { | |
45 | ret = -1; | |
46 | } | |
47 | ||
48 | lttng_uuid_copy(uuid_out, uuid_scan); | |
49 | end: | |
50 | return ret; | |
51 | } | |
52 | ||
53 | bool lttng_uuid_is_equal(const lttng_uuid a, const lttng_uuid b) | |
54 | { | |
55 | return memcmp(a, b, LTTNG_UUID_LEN) == 0; | |
56 | } | |
57 | ||
58 | bool lttng_uuid_is_nil(const lttng_uuid uuid) | |
59 | { | |
60 | return memcmp(nil_uuid, uuid, sizeof(lttng_uuid)) == 0; | |
61 | } | |
62 | ||
63 | void lttng_uuid_copy(lttng_uuid dst, const lttng_uuid src) | |
64 | { | |
65 | memcpy(dst, src, LTTNG_UUID_LEN); | |
66 | } | |
67 | ||
68 | /* | |
69 | * Generate a random UUID according to RFC4122, section 4.4. | |
70 | */ | |
71 | int lttng_uuid_generate(lttng_uuid uuid_out) | |
72 | { | |
73 | int i, ret = 0; | |
74 | ||
75 | if (uuid_out == NULL) { | |
76 | ret = -1; | |
77 | goto end; | |
78 | } | |
79 | ||
80 | if (!lttng_uuid_is_init) { | |
81 | /* | |
82 | * We don't need cryptographic quality randomness to | |
83 | * generate UUIDs, seed rand with the epoch. | |
84 | */ | |
85 | const time_t epoch = time(NULL); | |
86 | ||
87 | if (epoch == (time_t) -1) { | |
88 | ret = -1; | |
89 | goto end; | |
90 | } | |
91 | srand(epoch); | |
92 | ||
93 | lttng_uuid_is_init = true; | |
94 | } | |
95 | ||
96 | /* | |
97 | * Generate 16 bytes of random bits. | |
98 | */ | |
99 | for (i = 0; i < LTTNG_UUID_LEN; i++) { | |
100 | uuid_out[i] = (uint8_t) rand(); | |
101 | } | |
102 | ||
103 | /* | |
104 | * Set the two most significant bits (bits 6 and 7) of the | |
105 | * clock_seq_hi_and_reserved to zero and one, respectively. | |
106 | */ | |
107 | uuid_out[8] &= ~(1 << 6); | |
108 | uuid_out[8] |= (1 << 7); | |
109 | ||
110 | /* | |
111 | * Set the four most significant bits (bits 12 through 15) of the | |
112 | * time_hi_and_version field to the 4-bit version number from | |
113 | * Section 4.1.3. | |
114 | */ | |
115 | uuid_out[6] &= 0x0f; | |
116 | uuid_out[6] |= (LTTNG_UUID_VER << 4); | |
117 | ||
118 | end: | |
119 | return ret; | |
120 | } |