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/>.
30 _public_ char *sd_id128_to_string(sd_id128_t id, char s[33]) {
33 assert_return(s, NULL);
35 for (n = 0; n < 16; n++) {
36 s[n*2] = hexchar(id.bytes[n] >> 4);
37 s[n*2+1] = hexchar(id.bytes[n] & 0xF);
45 _public_ int sd_id128_from_string(const char s[], sd_id128_t *ret) {
50 assert_return(s, -EINVAL);
51 assert_return(ret, -EINVAL);
53 for (n = 0, i = 0; n < 16;) {
57 /* Is this a GUID? Then be nice, and skip over
62 else if (i == 13 || i == 18 || i == 23) {
72 a = unhexchar(s[i++]);
76 b = unhexchar(s[i++]);
80 t.bytes[n++] = (a << 4) | b;
83 if (i != (is_guid ? 36 : 32))
93 static sd_id128_t make_v4_uuid(sd_id128_t id) {
94 /* Stolen from generate_random_uuid() of drivers/char/random.c
95 * in the kernel sources */
97 /* Set UUID version to 4 --- truly random generation */
98 id.bytes[6] = (id.bytes[6] & 0x0F) | 0x40;
100 /* Set the UUID variant to DCE */
101 id.bytes[8] = (id.bytes[8] & 0x3F) | 0x80;
106 _public_ int sd_id128_get_machine(sd_id128_t *ret) {
107 static thread_local sd_id128_t saved_machine_id;
108 static thread_local bool saved_machine_id_valid = false;
109 _cleanup_close_ int fd = -1;
115 assert_return(ret, -EINVAL);
117 if (saved_machine_id_valid) {
118 *ret = saved_machine_id;
122 fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
126 k = loop_read(fd, buf, 33, false);
136 for (j = 0; j < 16; j++) {
139 a = unhexchar(buf[j*2]);
140 b = unhexchar(buf[j*2+1]);
145 t.bytes[j] = a << 4 | b;
148 saved_machine_id = t;
149 saved_machine_id_valid = true;
155 _public_ int sd_id128_get_boot(sd_id128_t *ret) {
156 static thread_local sd_id128_t saved_boot_id;
157 static thread_local bool saved_boot_id_valid = false;
158 _cleanup_close_ int fd = -1;
165 assert_return(ret, -EINVAL);
167 if (saved_boot_id_valid) {
168 *ret = saved_boot_id;
172 fd = open("/proc/sys/kernel/random/boot_id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
176 k = loop_read(fd, buf, 36, false);
183 for (j = 0, p = buf; j < 16; j++) {
198 t.bytes[j] = a << 4 | b;
204 saved_boot_id_valid = true;
210 _public_ int sd_id128_randomize(sd_id128_t *ret) {
211 _cleanup_close_ int fd = -1;
215 assert_return(ret, -EINVAL);
217 fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY);
221 k = loop_read(fd, &t, 16, false);
228 /* Turn this into a valid v4 UUID, to be nice. Note that we
229 * only guarantee this for newly generated UUIDs, not for
230 * pre-existing ones.*/
232 *ret = make_v4_uuid(t);