| 1 | /* |
| 2 | * Copyright (C) 2018 Jérémie Galarneau <jeremie.galarneau@efficios.com> |
| 3 | * Copyright (C) 2019 Michael Jeanson <mjeanson@efficios.com> |
| 4 | * |
| 5 | * This library is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU Lesser General Public License, version 2.1 only, |
| 7 | * as published by the Free Software Foundation. |
| 8 | * |
| 9 | * This library is distributed in the hope that it will be useful, but WITHOUT |
| 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License |
| 12 | * for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU Lesser General Public License |
| 15 | * along with this library; if not, write to the Free Software Foundation, |
| 16 | * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 17 | */ |
| 18 | |
| 19 | #include <common/compat/string.h> |
| 20 | #include <stddef.h> |
| 21 | #include <stdint.h> |
| 22 | #include <stdio.h> |
| 23 | #include <stdlib.h> |
| 24 | #include <string.h> |
| 25 | #include <time.h> |
| 26 | |
| 27 | #include "uuid.h" |
| 28 | |
| 29 | static const lttng_uuid nil_uuid; |
| 30 | static bool lttng_uuid_is_init; |
| 31 | |
| 32 | void lttng_uuid_to_str(const lttng_uuid uuid, char *uuid_str) |
| 33 | { |
| 34 | sprintf(uuid_str, LTTNG_UUID_FMT, LTTNG_UUID_FMT_VALUES(uuid)); |
| 35 | } |
| 36 | |
| 37 | int lttng_uuid_from_str(const char *str_in, lttng_uuid uuid_out) |
| 38 | { |
| 39 | int ret = 0; |
| 40 | lttng_uuid uuid_scan; |
| 41 | |
| 42 | if ((str_in == NULL) || (uuid_out == NULL)) { |
| 43 | ret = -1; |
| 44 | goto end; |
| 45 | } |
| 46 | |
| 47 | if (lttng_strnlen(str_in, LTTNG_UUID_STR_LEN) != LTTNG_UUID_STR_LEN - 1) { |
| 48 | ret = -1; |
| 49 | goto end; |
| 50 | } |
| 51 | |
| 52 | /* Scan to a temporary location in case of a partial match. */ |
| 53 | if (sscanf(str_in, LTTNG_UUID_FMT, LTTNG_UUID_SCAN_VALUES(uuid_scan)) != |
| 54 | LTTNG_UUID_LEN) { |
| 55 | ret = -1; |
| 56 | } |
| 57 | |
| 58 | lttng_uuid_copy(uuid_out, uuid_scan); |
| 59 | end: |
| 60 | return ret; |
| 61 | } |
| 62 | |
| 63 | bool lttng_uuid_is_equal(const lttng_uuid a, const lttng_uuid b) |
| 64 | { |
| 65 | return memcmp(a, b, LTTNG_UUID_LEN) == 0; |
| 66 | } |
| 67 | |
| 68 | bool lttng_uuid_is_nil(const lttng_uuid uuid) |
| 69 | { |
| 70 | return memcmp(nil_uuid, uuid, sizeof(lttng_uuid)) == 0; |
| 71 | } |
| 72 | |
| 73 | void lttng_uuid_copy(lttng_uuid dst, const lttng_uuid src) |
| 74 | { |
| 75 | memcpy(dst, src, LTTNG_UUID_LEN); |
| 76 | } |
| 77 | |
| 78 | /* |
| 79 | * Generate a random UUID according to RFC4122, section 4.4. |
| 80 | */ |
| 81 | int lttng_uuid_generate(lttng_uuid uuid_out) |
| 82 | { |
| 83 | int i, ret = 0; |
| 84 | |
| 85 | if (uuid_out == NULL) { |
| 86 | ret = -1; |
| 87 | goto end; |
| 88 | } |
| 89 | |
| 90 | if (!lttng_uuid_is_init) { |
| 91 | /* |
| 92 | * We don't need cryptographic quality randomness to |
| 93 | * generate UUIDs, seed rand with the epoch. |
| 94 | */ |
| 95 | const time_t epoch = time(NULL); |
| 96 | |
| 97 | if (epoch == (time_t) -1) { |
| 98 | ret = -1; |
| 99 | goto end; |
| 100 | } |
| 101 | srand(epoch); |
| 102 | |
| 103 | lttng_uuid_is_init = true; |
| 104 | } |
| 105 | |
| 106 | /* |
| 107 | * Generate 16 bytes of random bits. |
| 108 | */ |
| 109 | for (i = 0; i < LTTNG_UUID_LEN; i++) { |
| 110 | uuid_out[i] = (uint8_t) rand(); |
| 111 | } |
| 112 | |
| 113 | /* |
| 114 | * Set the two most significant bits (bits 6 and 7) of the |
| 115 | * clock_seq_hi_and_reserved to zero and one, respectively. |
| 116 | */ |
| 117 | uuid_out[8] &= ~(1 << 6); |
| 118 | uuid_out[8] |= (1 << 7); |
| 119 | |
| 120 | /* |
| 121 | * Set the four most significant bits (bits 12 through 15) of the |
| 122 | * time_hi_and_version field to the 4-bit version number from |
| 123 | * Section 4.1.3. |
| 124 | */ |
| 125 | uuid_out[6] &= 0x0f; |
| 126 | uuid_out[6] |= (LTTNG_UUID_VER << 4); |
| 127 | |
| 128 | end: |
| 129 | return ret; |
| 130 | } |