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/>.
29 #include "random-util.h"
31 _public_
char *sd_id128_to_string(sd_id128_t id
, char s
[SD_ID128_STRING_MAX
]) {
34 assert_return(s
, NULL
);
36 for (n
= 0; n
< 16; n
++) {
37 s
[n
*2] = hexchar(id
.bytes
[n
] >> 4);
38 s
[n
*2+1] = hexchar(id
.bytes
[n
] & 0xF);
46 _public_
int sd_id128_from_string(const char s
[], sd_id128_t
*ret
) {
51 assert_return(s
, -EINVAL
);
52 assert_return(ret
, -EINVAL
);
54 for (n
= 0, i
= 0; n
< 16;) {
58 /* Is this a GUID? Then be nice, and skip over
63 else if (i
== 13 || i
== 18 || i
== 23) {
73 a
= unhexchar(s
[i
++]);
77 b
= unhexchar(s
[i
++]);
81 t
.bytes
[n
++] = (a
<< 4) | b
;
84 if (i
!= (is_guid
? 36 : 32))
94 static sd_id128_t
make_v4_uuid(sd_id128_t id
) {
95 /* Stolen from generate_random_uuid() of drivers/char/random.c
96 * in the kernel sources */
98 /* Set UUID version to 4 --- truly random generation */
99 id
.bytes
[6] = (id
.bytes
[6] & 0x0F) | 0x40;
101 /* Set the UUID variant to DCE */
102 id
.bytes
[8] = (id
.bytes
[8] & 0x3F) | 0x80;
107 _public_
int sd_id128_get_machine(sd_id128_t
*ret
) {
108 static thread_local sd_id128_t saved_machine_id
;
109 static thread_local
bool saved_machine_id_valid
= false;
110 _cleanup_close_
int fd
= -1;
116 assert_return(ret
, -EINVAL
);
118 if (saved_machine_id_valid
) {
119 *ret
= saved_machine_id
;
123 fd
= open("/etc/machine-id", O_RDONLY
|O_CLOEXEC
|O_NOCTTY
);
127 r
= loop_read_exact(fd
, buf
, 33, false);
133 for (j
= 0; j
< 16; j
++) {
136 a
= unhexchar(buf
[j
*2]);
137 b
= unhexchar(buf
[j
*2+1]);
142 t
.bytes
[j
] = a
<< 4 | b
;
145 saved_machine_id
= t
;
146 saved_machine_id_valid
= true;
152 _public_
int sd_id128_get_boot(sd_id128_t
*ret
) {
153 static thread_local sd_id128_t saved_boot_id
;
154 static thread_local
bool saved_boot_id_valid
= false;
155 _cleanup_close_
int fd
= -1;
162 assert_return(ret
, -EINVAL
);
164 if (saved_boot_id_valid
) {
165 *ret
= saved_boot_id
;
169 fd
= open("/proc/sys/kernel/random/boot_id", O_RDONLY
|O_CLOEXEC
|O_NOCTTY
);
173 r
= loop_read_exact(fd
, buf
, 36, false);
177 for (j
= 0, p
= buf
; j
< 16; j
++) {
195 t
.bytes
[j
] = a
<< 4 | b
;
201 saved_boot_id_valid
= true;
207 _public_
int sd_id128_randomize(sd_id128_t
*ret
) {
211 assert_return(ret
, -EINVAL
);
213 r
= dev_urandom(&t
, sizeof(t
));
217 /* Turn this into a valid v4 UUID, to be nice. Note that we
218 * only guarantee this for newly generated UUIDs, not for
219 * pre-existing ones. */
221 *ret
= make_v4_uuid(t
);