2 This file is part of systemd.
4 Copyright 2011 Lennart Poettering
6 systemd is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published by
8 the Free Software Foundation; either version 2.1 of the License, or
9 (at your option) any later version.
11 systemd is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public License
17 along with systemd; If not, see <http://www.gnu.org/licenses/>.
27 #include "hexdecoct.h"
30 #include "random-util.h"
33 _public_ char *sd_id128_to_string(sd_id128_t id, char s[SD_ID128_STRING_MAX]) {
36 assert_return(s, NULL);
38 for (n = 0; n < 16; n++) {
39 s[n*2] = hexchar(id.bytes[n] >> 4);
40 s[n*2+1] = hexchar(id.bytes[n] & 0xF);
48 _public_ int sd_id128_from_string(const char s[], sd_id128_t *ret) {
53 assert_return(s, -EINVAL);
54 assert_return(ret, -EINVAL);
56 for (n = 0, i = 0; n < 16;) {
60 /* Is this a GUID? Then be nice, and skip over
65 else if (i == 13 || i == 18 || i == 23) {
75 a = unhexchar(s[i++]);
79 b = unhexchar(s[i++]);
83 t.bytes[n++] = (a << 4) | b;
86 if (i != (is_guid ? 36 : 32))
96 static sd_id128_t make_v4_uuid(sd_id128_t id) {
97 /* Stolen from generate_random_uuid() of drivers/char/random.c
98 * in the kernel sources */
100 /* Set UUID version to 4 --- truly random generation */
101 id.bytes[6] = (id.bytes[6] & 0x0F) | 0x40;
103 /* Set the UUID variant to DCE */
104 id.bytes[8] = (id.bytes[8] & 0x3F) | 0x80;
109 _public_ int sd_id128_get_machine(sd_id128_t *ret) {
110 static thread_local sd_id128_t saved_machine_id;
111 static thread_local bool saved_machine_id_valid = false;
112 _cleanup_close_ int fd = -1;
118 assert_return(ret, -EINVAL);
120 if (saved_machine_id_valid) {
121 *ret = saved_machine_id;
125 fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
129 r = loop_read_exact(fd, buf, 33, false);
135 for (j = 0; j < 16; j++) {
138 a = unhexchar(buf[j*2]);
139 b = unhexchar(buf[j*2+1]);
144 t.bytes[j] = a << 4 | b;
147 saved_machine_id = t;
148 saved_machine_id_valid = true;
154 _public_ int sd_id128_get_boot(sd_id128_t *ret) {
155 static thread_local sd_id128_t saved_boot_id;
156 static thread_local bool saved_boot_id_valid = false;
157 _cleanup_close_ int fd = -1;
164 assert_return(ret, -EINVAL);
166 if (saved_boot_id_valid) {
167 *ret = saved_boot_id;
171 fd = open("/proc/sys/kernel/random/boot_id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
175 r = loop_read_exact(fd, buf, 36, false);
179 for (j = 0, p = buf; j < 16; j++) {
197 t.bytes[j] = a << 4 | b;
203 saved_boot_id_valid = true;
209 _public_ int sd_id128_randomize(sd_id128_t *ret) {
213 assert_return(ret, -EINVAL);
215 r = dev_urandom(&t, sizeof(t));
219 /* Turn this into a valid v4 UUID, to be nice. Note that we
220 * only guarantee this for newly generated UUIDs, not for
221 * pre-existing ones. */
223 *ret = make_v4_uuid(t);