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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2011 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include "util.h"
#include "macro.h"
#include "sd-id128.h"
#include "random-util.h"
_public_ char *sd_id128_to_string(sd_id128_t id, char s[SD_ID128_STRING_MAX]) {
unsigned n;
assert_return(s, NULL);
for (n = 0; n < 16; n++) {
s[n*2] = hexchar(id.bytes[n] >> 4);
s[n*2+1] = hexchar(id.bytes[n] & 0xF);
}
s[32] = 0;
return s;
}
_public_ int sd_id128_from_string(const char s[], sd_id128_t *ret) {
unsigned n, i;
sd_id128_t t;
bool is_guid = false;
assert_return(s, -EINVAL);
assert_return(ret, -EINVAL);
for (n = 0, i = 0; n < 16;) {
int a, b;
if (s[i] == '-') {
/* Is this a GUID? Then be nice, and skip over
* the dashes */
if (i == 8)
is_guid = true;
else if (i == 13 || i == 18 || i == 23) {
if (!is_guid)
return -EINVAL;
} else
return -EINVAL;
i++;
continue;
}
a = unhexchar(s[i++]);
if (a < 0)
return -EINVAL;
b = unhexchar(s[i++]);
if (b < 0)
return -EINVAL;
t.bytes[n++] = (a << 4) | b;
}
if (i != (is_guid ? 36 : 32))
return -EINVAL;
if (s[i] != 0)
return -EINVAL;
*ret = t;
return 0;
}
static sd_id128_t make_v4_uuid(sd_id128_t id) {
/* Stolen from generate_random_uuid() of drivers/char/random.c
* in the kernel sources */
/* Set UUID version to 4 --- truly random generation */
id.bytes[6] = (id.bytes[6] & 0x0F) | 0x40;
/* Set the UUID variant to DCE */
id.bytes[8] = (id.bytes[8] & 0x3F) | 0x80;
return id;
}
_public_ int sd_id128_get_machine(sd_id128_t *ret) {
static thread_local sd_id128_t saved_machine_id;
static thread_local bool saved_machine_id_valid = false;
_cleanup_close_ int fd = -1;
char buf[33];
unsigned j;
sd_id128_t t;
int r;
assert_return(ret, -EINVAL);
if (saved_machine_id_valid) {
*ret = saved_machine_id;
return 0;
}
fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (fd < 0)
return -errno;
r = loop_read_exact(fd, buf, 33, false);
if (r < 0)
return r;
if (buf[32] !='\n')
return -EIO;
for (j = 0; j < 16; j++) {
int a, b;
a = unhexchar(buf[j*2]);
b = unhexchar(buf[j*2+1]);
if (a < 0 || b < 0)
return -EIO;
t.bytes[j] = a << 4 | b;
}
saved_machine_id = t;
saved_machine_id_valid = true;
*ret = t;
return 0;
}
_public_ int sd_id128_get_boot(sd_id128_t *ret) {
static thread_local sd_id128_t saved_boot_id;
static thread_local bool saved_boot_id_valid = false;
_cleanup_close_ int fd = -1;
char buf[36];
unsigned j;
sd_id128_t t;
char *p;
int r;
assert_return(ret, -EINVAL);
if (saved_boot_id_valid) {
*ret = saved_boot_id;
return 0;
}
fd = open("/proc/sys/kernel/random/boot_id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (fd < 0)
return -errno;
r = loop_read_exact(fd, buf, 36, false);
if (r < 0)
return r;
for (j = 0, p = buf; j < 16; j++) {
int a, b;
if (p >= buf + 35)
return -EIO;
if (*p == '-') {
p++;
if (p >= buf + 35)
return -EIO;
}
a = unhexchar(p[0]);
b = unhexchar(p[1]);
if (a < 0 || b < 0)
return -EIO;
t.bytes[j] = a << 4 | b;
p += 2;
}
saved_boot_id = t;
saved_boot_id_valid = true;
*ret = t;
return 0;
}
_public_ int sd_id128_randomize(sd_id128_t *ret) {
sd_id128_t t;
int r;
assert_return(ret, -EINVAL);
r = dev_urandom(&t, sizeof(t));
if (r < 0)
return r;
/* Turn this into a valid v4 UUID, to be nice. Note that we
* only guarantee this for newly generated UUIDs, not for
* pre-existing ones. */
*ret = make_v4_uuid(t);
return 0;
}
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