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 General Public License as published by
10 the Free Software Foundation; either version 2 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 General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
31 _public_ char *sd_id128_to_string(sd_id128_t id, char s[33]) {
37 for (n = 0; n < 16; n++) {
38 s[n*2] = hexchar(id.bytes[n] >> 4);
39 s[n*2+1] = hexchar(id.bytes[n] & 0xF);
47 _public_ int sd_id128_from_string(const char s[33], sd_id128_t *ret) {
56 for (n = 0; n < 16; n++) {
59 a = unhexchar(s[n*2]);
63 b = unhexchar(s[n*2+1]);
67 t.bytes[n] = (a << 4) | b;
77 static sd_id128_t make_v4_uuid(sd_id128_t id) {
78 /* Stolen from generate_random_uuid() of drivers/char/random.c
79 * in the kernel sources */
81 /* Set UUID version to 4 --- truly random generation */
82 id.bytes[6] = (id.bytes[6] & 0x0F) | 0x40;
84 /* Set the UUID variant to DCE */
85 id.bytes[8] = (id.bytes[8] & 0x3F) | 0x80;
90 _public_ int sd_id128_get_machine(sd_id128_t *ret) {
91 static __thread sd_id128_t saved_machine_id;
92 static __thread bool saved_machine_id_valid = false;
102 if (saved_machine_id_valid) {
103 *ret = saved_machine_id;
107 fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
111 k = loop_read(fd, buf, 32, false);
112 close_nointr_nofail(fd);
120 for (j = 0; j < 16; j++) {
123 a = unhexchar(buf[j*2]);
124 b = unhexchar(buf[j*2+1]);
129 t.bytes[j] = a << 4 | b;
132 saved_machine_id = t;
133 saved_machine_id_valid = true;
139 _public_ int sd_id128_get_boot(sd_id128_t *ret) {
140 static __thread sd_id128_t saved_boot_id;
141 static __thread bool saved_boot_id_valid = false;
152 if (saved_boot_id_valid) {
153 *ret = saved_boot_id;
157 fd = open("/proc/sys/kernel/random/boot_id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
161 k = loop_read(fd, buf, 36, false);
162 close_nointr_nofail(fd);
170 for (j = 0, p = buf; j < 16; j++) {
182 t.bytes[j] = a << 4 | b;
188 saved_boot_id_valid = true;
194 _public_ int sd_id128_randomize(sd_id128_t *ret) {
202 fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY);
206 k = loop_read(fd, &t, 16, false);
207 close_nointr_nofail(fd);
215 /* Turn this into a valid v4 UUID, to be nice. Note that we
216 * only guarantee this for newly generated UUIDs, not for
217 * pre-existing ones.*/
219 *ret = make_v4_uuid(t);