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/>.
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);