1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
4 This file is part of systemd.
6 Copyright 2011 Lennart Poettering
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Lesser General Public License for more details.
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
29 #include "hexdecoct.h"
32 #include "random-util.h"
35 _public_ char *sd_id128_to_string(sd_id128_t id, char s[SD_ID128_STRING_MAX]) {
38 assert_return(s, NULL);
40 for (n = 0; n < 16; n++) {
41 s[n*2] = hexchar(id.bytes[n] >> 4);
42 s[n*2+1] = hexchar(id.bytes[n] & 0xF);
50 _public_ int sd_id128_from_string(const char s[], sd_id128_t *ret) {
55 assert_return(s, -EINVAL);
56 assert_return(ret, -EINVAL);
58 for (n = 0, i = 0; n < 16;) {
62 /* Is this a GUID? Then be nice, and skip over
67 else if (i == 13 || i == 18 || i == 23) {
77 a = unhexchar(s[i++]);
81 b = unhexchar(s[i++]);
85 t.bytes[n++] = (a << 4) | b;
88 if (i != (is_guid ? 36 : 32))
98 static sd_id128_t make_v4_uuid(sd_id128_t id) {
99 /* Stolen from generate_random_uuid() of drivers/char/random.c
100 * in the kernel sources */
102 /* Set UUID version to 4 --- truly random generation */
103 id.bytes[6] = (id.bytes[6] & 0x0F) | 0x40;
105 /* Set the UUID variant to DCE */
106 id.bytes[8] = (id.bytes[8] & 0x3F) | 0x80;
111 _public_ int sd_id128_get_machine(sd_id128_t *ret) {
112 static thread_local sd_id128_t saved_machine_id;
113 static thread_local bool saved_machine_id_valid = false;
114 _cleanup_close_ int fd = -1;
120 assert_return(ret, -EINVAL);
122 if (saved_machine_id_valid) {
123 *ret = saved_machine_id;
127 fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
131 r = loop_read_exact(fd, buf, 33, false);
137 for (j = 0; j < 16; j++) {
140 a = unhexchar(buf[j*2]);
141 b = unhexchar(buf[j*2+1]);
146 t.bytes[j] = a << 4 | b;
149 saved_machine_id = t;
150 saved_machine_id_valid = true;
156 _public_ int sd_id128_get_boot(sd_id128_t *ret) {
157 static thread_local sd_id128_t saved_boot_id;
158 static thread_local bool saved_boot_id_valid = false;
159 _cleanup_close_ int fd = -1;
166 assert_return(ret, -EINVAL);
168 if (saved_boot_id_valid) {
169 *ret = saved_boot_id;
173 fd = open("/proc/sys/kernel/random/boot_id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
177 r = loop_read_exact(fd, buf, 36, false);
181 for (j = 0, p = buf; j < 16; j++) {
199 t.bytes[j] = a << 4 | b;
205 saved_boot_id_valid = true;
211 _public_ int sd_id128_randomize(sd_id128_t *ret) {
215 assert_return(ret, -EINVAL);
217 r = dev_urandom(&t, sizeof(t));
221 /* Turn this into a valid v4 UUID, to be nice. Note that we
222 * only guarantee this for newly generated UUIDs, not for
223 * pre-existing ones. */
225 *ret = make_v4_uuid(t);