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[], sd_id128_t *ret) {
57 for (n = 0, i = 0; n < 16;) {
61 /* Is this a GUID? Then be nice, and skip over
66 else if (i == 13 || i == 18 || i == 23) {
76 a = unhexchar(s[i++]);
80 b = unhexchar(s[i++]);
84 t.bytes[n++] = (a << 4) | b;
87 if (i != (is_guid ? 36 : 32))
97 static sd_id128_t make_v4_uuid(sd_id128_t id) {
98 /* Stolen from generate_random_uuid() of drivers/char/random.c
99 * in the kernel sources */
101 /* Set UUID version to 4 --- truly random generation */
102 id.bytes[6] = (id.bytes[6] & 0x0F) | 0x40;
104 /* Set the UUID variant to DCE */
105 id.bytes[8] = (id.bytes[8] & 0x3F) | 0x80;
110 _public_ int sd_id128_get_machine(sd_id128_t *ret) {
111 static __thread sd_id128_t saved_machine_id;
112 static __thread bool saved_machine_id_valid = false;
113 _cleanup_close_ int fd = -1;
122 if (saved_machine_id_valid) {
123 *ret = saved_machine_id;
127 fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
131 k = loop_read(fd, buf, 33, false);
141 for (j = 0; j < 16; j++) {
144 a = unhexchar(buf[j*2]);
145 b = unhexchar(buf[j*2+1]);
150 t.bytes[j] = a << 4 | b;
153 saved_machine_id = t;
154 saved_machine_id_valid = true;
160 _public_ int sd_id128_get_boot(sd_id128_t *ret) {
161 static __thread sd_id128_t saved_boot_id;
162 static __thread bool saved_boot_id_valid = false;
163 _cleanup_close_ int fd = -1;
173 if (saved_boot_id_valid) {
174 *ret = saved_boot_id;
178 fd = open("/proc/sys/kernel/random/boot_id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
182 k = loop_read(fd, buf, 36, false);
189 for (j = 0, p = buf; j < 16; j++) {
204 t.bytes[j] = a << 4 | b;
210 saved_boot_id_valid = true;
216 _public_ int sd_id128_randomize(sd_id128_t *ret) {
217 _cleanup_close_ int fd = -1;
224 fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY);
228 k = loop_read(fd, &t, 16, false);
235 /* Turn this into a valid v4 UUID, to be nice. Note that we
236 * only guarantee this for newly generated UUIDs, not for
237 * pre-existing ones.*/
239 *ret = make_v4_uuid(t);