1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
|
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 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 <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/mount.h>
#include <systemd/sd-id128.h>
#include "machine-id-setup.h"
#include "macro.h"
#include "util.h"
#include "mkdir.h"
#include "log.h"
#include "virt.h"
#include "fileio.h"
static int shorten_uuid(char destination[36], const char *source) {
unsigned i, j;
for (i = 0, j = 0; i < 36 && j < 32; i++) {
int t;
t = unhexchar(source[i]);
if (t < 0)
continue;
destination[j++] = hexchar(t);
}
if (i == 36 && j == 32) {
destination[32] = '\n';
destination[33] = 0;
return 0;
}
return -EINVAL;
}
static int generate(char id[34]) {
int fd, r;
unsigned char *p;
sd_id128_t buf;
char *q;
ssize_t k;
const char *vm_id;
assert(id);
/* First, try reading the D-Bus machine id, unless it is a symlink */
fd = open("/var/lib/dbus/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
if (fd >= 0) {
k = loop_read(fd, id, 32, false);
close_nointr_nofail(fd);
if (k >= 32) {
id[32] = '\n';
id[33] = 0;
log_info("Initializing machine ID from D-Bus machine ID.");
return 0;
}
}
/* If that didn't work, see if we are running in qemu/kvm and a
* machine ID was passed in via -uuid on the qemu/kvm command
* line */
r = detect_vm(&vm_id);
if (r > 0 && streq(vm_id, "kvm")) {
char uuid[37];
fd = open("/sys/class/dmi/id/product_uuid", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
if (fd >= 0) {
k = loop_read(fd, uuid, 36, false);
close_nointr_nofail(fd);
if (k >= 36) {
r = shorten_uuid(id, uuid);
if (r >= 0) {
log_info("Initializing machine ID from KVM UUID.");
return 0;
}
}
}
}
/* If that didn't work either, see if we are running in a
* container, and a machine ID was passed in via
* $container_uuid the way libvirt/LXC does it */
r = detect_container(NULL);
if (r > 0) {
char *e;
r = getenv_for_pid(1, "container_uuid", &e);
if (r > 0) {
if (strlen(e) >= 36) {
r = shorten_uuid(id, e);
if (r >= 0) {
log_info("Initializing machine ID from container UUID.");
free(e);
return 0;
}
}
free(e);
}
}
/* If that didn't work, generate a random machine id */
r = sd_id128_randomize(&buf);
if (r < 0) {
log_error("Failed to open /dev/urandom: %s", strerror(-r));
return r;
}
for (p = buf.bytes, q = id; p < buf.bytes + sizeof(buf); p++, q += 2) {
q[0] = hexchar(*p >> 4);
q[1] = hexchar(*p & 15);
}
id[32] = '\n';
id[33] = 0;
log_info("Initializing machine ID from random generator.");
return 0;
}
int machine_id_setup(void) {
int fd, r;
bool writable;
struct stat st;
char id[34]; /* 32 + \n + \0 */
mode_t m;
m = umask(0000);
/* We create this 0444, to indicate that this isn't really
* something you should ever modify. Of course, since the file
* will be owned by root it doesn't matter much, but maybe
* people look. */
fd = open("/etc/machine-id", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444);
if (fd >= 0)
writable = true;
else {
fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY);
if (fd < 0) {
umask(m);
log_error("Cannot open /etc/machine-id: %m");
return -errno;
}
writable = false;
}
umask(m);
if (fstat(fd, &st) < 0) {
log_error("fstat() failed: %m");
r = -errno;
goto finish;
}
if (S_ISREG(st.st_mode)) {
if (loop_read(fd, id, 32, false) >= 32) {
r = 0;
goto finish;
}
}
/* Hmm, so, the id currently stored is not useful, then let's
* generate one */
r = generate(id);
if (r < 0)
goto finish;
if (S_ISREG(st.st_mode) && writable) {
lseek(fd, 0, SEEK_SET);
if (loop_write(fd, id, 33, false) == 33) {
r = 0;
goto finish;
}
}
close_nointr_nofail(fd);
fd = -1;
/* Hmm, we couldn't write it? So let's write it to
* /run/machine-id as a replacement */
m = umask(0022);
r = write_string_file("/run/machine-id", id);
umask(m);
if (r < 0) {
log_error("Cannot write /run/machine-id: %s", strerror(-r));
unlink("/run/machine-id");
goto finish;
}
/* And now, let's mount it over */
r = mount("/run/machine-id", "/etc/machine-id", NULL, MS_BIND, NULL) < 0 ? -errno : 0;
if (r < 0) {
unlink("/run/machine-id");
log_error("Failed to mount /etc/machine-id: %s", strerror(-r));
} else {
log_info("Installed transient /etc/machine-id file.");
/* Mark the mount read-only */
if (mount(NULL, "/etc/machine-id", NULL,
MS_BIND|MS_RDONLY|MS_REMOUNT, NULL) < 0)
log_warning("Failed to make transient /etc/machine-id read-only");
}
finish:
if (fd >= 0)
close_nointr_nofail(fd);
return r;
}
|
