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 r = loop_read_exact(fd, buf, 33, false);
132 for (j = 0; j < 16; j++) {
135 a = unhexchar(buf[j*2]);
136 b = unhexchar(buf[j*2+1]);
141 t.bytes[j] = a << 4 | b;
144 saved_machine_id = t;
145 saved_machine_id_valid = true;
151 _public_ int sd_id128_get_boot(sd_id128_t *ret) {
152 static thread_local sd_id128_t saved_boot_id;
153 static thread_local bool saved_boot_id_valid = false;
154 _cleanup_close_ int fd = -1;
161 assert_return(ret, -EINVAL);
163 if (saved_boot_id_valid) {
164 *ret = saved_boot_id;
168 fd = open("/proc/sys/kernel/random/boot_id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
172 r = loop_read_exact(fd, buf, 36, false);
176 for (j = 0, p = buf; j < 16; j++) {
194 t.bytes[j] = a << 4 | b;
200 saved_boot_id_valid = true;
206 _public_ int sd_id128_randomize(sd_id128_t *ret) {
210 assert_return(ret, -EINVAL);
212 r = dev_urandom(&t, sizeof(t));
216 /* Turn this into a valid v4 UUID, to be nice. Note that we
217 * only guarantee this for newly generated UUIDs, not for
218 * pre-existing ones. */
220 *ret = make_v4_uuid(t);