1 | /* guuid.c - UUID functions |
2 | * |
3 | * Copyright (C) 2013-2015, 2017 Red Hat, Inc. |
4 | * |
5 | * This library is free software; you can redistribute it and/or modify |
6 | * it under the terms of the GNU Lesser General Public License as |
7 | * published by the Free Software Foundation; either version 2.1 of the |
8 | * licence, or (at your option) any later version. |
9 | * |
10 | * This is distributed in the hope that it will be useful, but WITHOUT |
11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public |
13 | * License for more details. |
14 | * |
15 | * You should have received a copy of the GNU Lesser General Public |
16 | * License along with this library; if not, write to the Free Software |
17 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 |
18 | * USA. |
19 | * |
20 | * Authors: Marc-André Lureau <marcandre.lureau@redhat.com> |
21 | */ |
22 | |
23 | #include "config.h" |
24 | #include <string.h> |
25 | |
26 | #include "gi18n.h" |
27 | #include "gstrfuncs.h" |
28 | #include "grand.h" |
29 | #include "gmessages.h" |
30 | #include "gchecksum.h" |
31 | |
32 | #include "guuid.h" |
33 | |
34 | typedef struct { |
35 | guint8 bytes[16]; |
36 | } GUuid; |
37 | |
38 | /** |
39 | * SECTION:uuid |
40 | * @title: GUuid |
41 | * @short_description: a universally unique identifier |
42 | * |
43 | * A UUID, or Universally unique identifier, is intended to uniquely |
44 | * identify information in a distributed environment. For the |
45 | * definition of UUID, see [RFC 4122](https://tools.ietf.org/html/rfc4122.html). |
46 | * |
47 | * The creation of UUIDs does not require a centralized authority. |
48 | * |
49 | * UUIDs are of relatively small size (128 bits, or 16 bytes). The |
50 | * common string representation (ex: |
51 | * 1d6c0810-2bd6-45f3-9890-0268422a6f14) needs 37 bytes. |
52 | * |
53 | * The UUID specification defines 5 versions, and calling |
54 | * g_uuid_string_random() will generate a unique (or rather random) |
55 | * UUID of the most common version, version 4. |
56 | * |
57 | * Since: 2.52 |
58 | */ |
59 | |
60 | /* |
61 | * g_uuid_to_string: |
62 | * @uuid: a #GUuid |
63 | * |
64 | * Creates a string representation of @uuid, of the form |
65 | * 06e023d5-86d8-420e-8103-383e4566087a (no braces nor urn:uuid: |
66 | * prefix). |
67 | * |
68 | * Returns: (transfer full): A string that should be freed with g_free(). |
69 | * Since: STATIC |
70 | */ |
71 | static gchar * |
72 | g_uuid_to_string (const GUuid *uuid) |
73 | { |
74 | const guint8 *bytes; |
75 | |
76 | g_return_val_if_fail (uuid != NULL, NULL); |
77 | |
78 | bytes = uuid->bytes; |
79 | |
80 | return g_strdup_printf (format: "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x" |
81 | "-%02x%02x%02x%02x%02x%02x" , |
82 | bytes[0], bytes[1], bytes[2], bytes[3], |
83 | bytes[4], bytes[5], bytes[6], bytes[7], |
84 | bytes[8], bytes[9], bytes[10], bytes[11], |
85 | bytes[12], bytes[13], bytes[14], bytes[15]); |
86 | } |
87 | |
88 | static gboolean |
89 | uuid_parse_string (const gchar *str, |
90 | GUuid *uuid) |
91 | { |
92 | GUuid tmp; |
93 | guint8 *bytes = tmp.bytes; |
94 | gint i, j, hi, lo; |
95 | guint expected_len = 36; |
96 | |
97 | if (strlen (s: str) != expected_len) |
98 | return FALSE; |
99 | |
100 | for (i = 0, j = 0; i < 16;) |
101 | { |
102 | if (j == 8 || j == 13 || j == 18 || j == 23) |
103 | { |
104 | if (str[j++] != '-') |
105 | return FALSE; |
106 | |
107 | continue; |
108 | } |
109 | |
110 | hi = g_ascii_xdigit_value (c: str[j++]); |
111 | lo = g_ascii_xdigit_value (c: str[j++]); |
112 | |
113 | if (hi == -1 || lo == -1) |
114 | return FALSE; |
115 | |
116 | bytes[i++] = hi << 8 | lo; |
117 | } |
118 | |
119 | if (uuid != NULL) |
120 | *uuid = tmp; |
121 | |
122 | return TRUE; |
123 | } |
124 | |
125 | /** |
126 | * g_uuid_string_is_valid: |
127 | * @str: a string representing a UUID |
128 | * |
129 | * Parses the string @str and verify if it is a UUID. |
130 | * |
131 | * The function accepts the following syntax: |
132 | * |
133 | * - simple forms (e.g. `f81d4fae-7dec-11d0-a765-00a0c91e6bf6`) |
134 | * |
135 | * Note that hyphens are required within the UUID string itself, |
136 | * as per the aforementioned RFC. |
137 | * |
138 | * Returns: %TRUE if @str is a valid UUID, %FALSE otherwise. |
139 | * Since: 2.52 |
140 | */ |
141 | gboolean |
142 | g_uuid_string_is_valid (const gchar *str) |
143 | { |
144 | g_return_val_if_fail (str != NULL, FALSE); |
145 | |
146 | return uuid_parse_string (str, NULL); |
147 | } |
148 | |
149 | static void |
150 | uuid_set_version (GUuid *uuid, guint version) |
151 | { |
152 | guint8 *bytes = uuid->bytes; |
153 | |
154 | /* |
155 | * Set the four most significant bits (bits 12 through 15) of the |
156 | * time_hi_and_version field to the 4-bit version number from |
157 | * Section 4.1.3. |
158 | */ |
159 | bytes[6] &= 0x0f; |
160 | bytes[6] |= version << 4; |
161 | /* |
162 | * Set the two most significant bits (bits 6 and 7) of the |
163 | * clock_seq_hi_and_reserved to zero and one, respectively. |
164 | */ |
165 | bytes[8] &= 0x3f; |
166 | bytes[8] |= 0x80; |
167 | } |
168 | |
169 | /* |
170 | * g_uuid_generate_v4: |
171 | * @uuid: a #GUuid |
172 | * |
173 | * Generates a random UUID (RFC 4122 version 4). |
174 | * Since: STATIC |
175 | */ |
176 | static void |
177 | g_uuid_generate_v4 (GUuid *uuid) |
178 | { |
179 | int i; |
180 | guint8 *bytes; |
181 | guint32 *ints; |
182 | |
183 | g_return_if_fail (uuid != NULL); |
184 | |
185 | bytes = uuid->bytes; |
186 | ints = (guint32 *) bytes; |
187 | for (i = 0; i < 4; i++) |
188 | ints[i] = g_random_int (); |
189 | |
190 | uuid_set_version (uuid, version: 4); |
191 | } |
192 | |
193 | /** |
194 | * g_uuid_string_random: |
195 | * |
196 | * Generates a random UUID (RFC 4122 version 4) as a string. It has the same |
197 | * randomness guarantees as #GRand, so must not be used for cryptographic |
198 | * purposes such as key generation, nonces, salts or one-time pads. |
199 | * |
200 | * Returns: (transfer full): A string that should be freed with g_free(). |
201 | * Since: 2.52 |
202 | */ |
203 | gchar * |
204 | g_uuid_string_random (void) |
205 | { |
206 | GUuid uuid; |
207 | |
208 | g_uuid_generate_v4 (uuid: &uuid); |
209 | |
210 | return g_uuid_to_string (uuid: &uuid); |
211 | } |
212 | |