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d7ccca2e LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2010 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 2 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
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 | General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <unistd.h> | |
23 | #include <stdio.h> | |
24 | #include <errno.h> | |
25 | #include <string.h> | |
26 | #include <stdlib.h> | |
27 | #include <fcntl.h> | |
28 | #include <sys/mount.h> | |
29 | ||
81527be1 LP |
30 | #include <systemd/sd-id128.h> |
31 | ||
d7ccca2e LP |
32 | #include "machine-id-setup.h" |
33 | #include "macro.h" | |
34 | #include "util.h" | |
35 | #include "log.h" | |
d4eb120a | 36 | #include "virt.h" |
8d41a963 | 37 | |
09b967ea LP |
38 | static int shorten_uuid(char destination[36], const char *source) { |
39 | unsigned i, j; | |
40 | ||
41 | for (i = 0, j = 0; i < 36 && j < 32; i++) { | |
42 | int t; | |
43 | ||
44 | t = unhexchar(source[i]); | |
45 | if (t < 0) | |
46 | continue; | |
47 | ||
48 | destination[j++] = hexchar(t); | |
49 | } | |
50 | ||
51 | if (i == 36 && j == 32) { | |
52 | destination[32] = '\n'; | |
53 | destination[33] = 0; | |
54 | return 0; | |
55 | } | |
56 | ||
57 | return -EINVAL; | |
58 | } | |
59 | ||
d7ccca2e | 60 | static int generate(char id[34]) { |
87d2c1ff LP |
61 | int fd, r; |
62 | unsigned char *p; | |
63 | sd_id128_t buf; | |
8d41a963 | 64 | char *q; |
d7ccca2e | 65 | ssize_t k; |
d4eb120a | 66 | const char *vm_id; |
d7ccca2e LP |
67 | |
68 | assert(id); | |
69 | ||
70 | /* First, try reading the D-Bus machine id, unless it is a symlink */ | |
8d41a963 LP |
71 | fd = open("/var/lib/dbus/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); |
72 | if (fd >= 0) { | |
d7ccca2e | 73 | |
d4eb120a | 74 | k = loop_read(fd, id, 32, false); |
d7ccca2e LP |
75 | close_nointr_nofail(fd); |
76 | ||
77 | if (k >= 32) { | |
78 | id[32] = '\n'; | |
79 | id[33] = 0; | |
80 | ||
81 | log_info("Initializing machine ID from D-Bus machine ID."); | |
82 | return 0; | |
83 | } | |
84 | } | |
85 | ||
d4eb120a LP |
86 | /* If that didn't work, see if we are running in qemu/kvm and a |
87 | * machine ID was passed in via -uuid on the qemu/kvm command | |
88 | * line */ | |
89 | ||
90 | r = detect_vm(&vm_id); | |
91 | if (r > 0 && streq(vm_id, "kvm")) { | |
92 | char uuid[37]; | |
93 | ||
94 | fd = open("/sys/class/dmi/id/product_uuid", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); | |
95 | if (fd >= 0) { | |
96 | k = loop_read(fd, uuid, 36, false); | |
97 | close_nointr_nofail(fd); | |
98 | ||
99 | if (k >= 36) { | |
09b967ea LP |
100 | r = shorten_uuid(id, uuid); |
101 | if (r >= 0) { | |
102 | log_info("Initializing machine ID from KVM UUID"); | |
103 | return 0; | |
104 | } | |
105 | } | |
106 | } | |
107 | } | |
d4eb120a | 108 | |
09b967ea LP |
109 | /* If that didn't work either, see if we are running in a |
110 | * container, and a machine ID was passed in via | |
111 | * $container_uuid the way libvirt/LXC does it */ | |
d4eb120a | 112 | |
09b967ea LP |
113 | r = detect_container(NULL); |
114 | if (r > 0) { | |
115 | FILE *f; | |
d4eb120a | 116 | |
09b967ea LP |
117 | f = fopen("/proc/1/environ", "re"); |
118 | if (f) { | |
119 | bool done = false; | |
d4eb120a | 120 | |
09b967ea LP |
121 | do { |
122 | char line[LINE_MAX]; | |
123 | unsigned i; | |
d4eb120a | 124 | |
09b967ea LP |
125 | for (i = 0; i < sizeof(line)-1; i++) { |
126 | int c; | |
127 | ||
128 | c = getc(f); | |
129 | if (_unlikely_(c == EOF)) { | |
130 | done = true; | |
131 | break; | |
132 | } else if (c == 0) | |
133 | break; | |
134 | ||
135 | line[i] = c; | |
d4eb120a | 136 | } |
09b967ea LP |
137 | line[i] = 0; |
138 | ||
139 | if (startswith(line, "container_uuid=") && | |
140 | strlen(line + 15) >= 36) { | |
141 | r = shorten_uuid(id, line + 15); | |
142 | if (r >= 0) { | |
143 | log_info("Initializing machine ID from container UUID"); | |
144 | return 0; | |
145 | } | |
146 | } | |
147 | ||
148 | } while (!done); | |
149 | ||
150 | fclose(f); | |
d4eb120a LP |
151 | } |
152 | } | |
153 | ||
d7ccca2e | 154 | /* If that didn't work, generate a random machine id */ |
87d2c1ff LP |
155 | r = sd_id128_randomize(&buf); |
156 | if (r < 0) { | |
157 | log_error("Failed to open /dev/urandom: %s", strerror(-r)); | |
158 | return r; | |
d7ccca2e LP |
159 | } |
160 | ||
87d2c1ff | 161 | for (p = buf.bytes, q = id; p < buf.bytes + sizeof(buf); p++, q += 2) { |
d7ccca2e LP |
162 | q[0] = hexchar(*p >> 4); |
163 | q[1] = hexchar(*p & 15); | |
164 | } | |
165 | ||
166 | id[32] = '\n'; | |
167 | id[33] = 0; | |
168 | ||
169 | log_info("Initializing machine ID from random generator."); | |
170 | ||
171 | return 0; | |
172 | } | |
173 | ||
174 | int machine_id_setup(void) { | |
175 | int fd, r; | |
176 | bool writable; | |
177 | struct stat st; | |
178 | char id[34]; /* 32 + \n + \0 */ | |
179 | mode_t m; | |
180 | ||
181 | m = umask(0000); | |
182 | ||
76526bad LP |
183 | /* We create this 0444, to indicate that this isn't really |
184 | * something you should ever modify. Of course, since the file | |
185 | * will be owned by root it doesn't matter much, but maybe | |
186 | * people look. */ | |
187 | ||
8d41a963 LP |
188 | fd = open("/etc/machine-id", O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444); |
189 | if (fd >= 0) | |
d7ccca2e LP |
190 | writable = true; |
191 | else { | |
8d41a963 LP |
192 | fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY); |
193 | if (fd < 0) { | |
d7ccca2e LP |
194 | umask(m); |
195 | log_error("Cannot open /etc/machine-id: %m"); | |
196 | return -errno; | |
197 | } | |
198 | ||
199 | writable = false; | |
200 | } | |
201 | ||
202 | umask(m); | |
203 | ||
204 | if (fstat(fd, &st) < 0) { | |
205 | log_error("fstat() failed: %m"); | |
206 | r = -errno; | |
207 | goto finish; | |
208 | } | |
209 | ||
210 | if (S_ISREG(st.st_mode)) { | |
211 | if (loop_read(fd, id, 32, false) >= 32) { | |
212 | r = 0; | |
213 | goto finish; | |
214 | } | |
215 | } | |
216 | ||
217 | /* Hmm, so, the id currently stored is not useful, then let's | |
218 | * generate one */ | |
219 | ||
8d41a963 LP |
220 | r = generate(id); |
221 | if (r < 0) | |
d7ccca2e LP |
222 | goto finish; |
223 | ||
224 | if (S_ISREG(st.st_mode) && writable) { | |
225 | lseek(fd, 0, SEEK_SET); | |
226 | ||
227 | if (loop_write(fd, id, 33, false) == 33) { | |
228 | r = 0; | |
229 | goto finish; | |
230 | } | |
231 | } | |
232 | ||
233 | close_nointr_nofail(fd); | |
234 | fd = -1; | |
235 | ||
236 | /* Hmm, we couldn't write it? So let's write it to | |
2b583ce6 | 237 | * /run/systemd/machine-id as a replacement */ |
d7ccca2e | 238 | |
2b583ce6 | 239 | mkdir_p("/run/systemd", 0755); |
d7ccca2e | 240 | |
4c12626c | 241 | m = umask(0022); |
8d41a963 | 242 | r = write_one_line_file("/run/systemd/machine-id", id); |
4c12626c LP |
243 | umask(m); |
244 | ||
8d41a963 | 245 | if (r < 0) { |
2b583ce6 | 246 | log_error("Cannot write /run/systemd/machine-id: %s", strerror(-r)); |
d7ccca2e | 247 | |
2b583ce6 | 248 | unlink("/run/systemd/machine-id"); |
d7ccca2e LP |
249 | goto finish; |
250 | } | |
251 | ||
252 | /* And now, let's mount it over */ | |
2b583ce6 KS |
253 | r = mount("/run/systemd/machine-id", "/etc/machine-id", "bind", MS_BIND|MS_RDONLY, NULL) < 0 ? -errno : 0; |
254 | unlink("/run/systemd/machine-id"); | |
d7ccca2e LP |
255 | |
256 | if (r < 0) | |
257 | log_error("Failed to mount /etc/machine-id: %s", strerror(-r)); | |
258 | else | |
9b4f818b | 259 | log_info("Installed transient /etc/machine-id file."); |
d7ccca2e LP |
260 | |
261 | finish: | |
262 | ||
263 | if (fd >= 0) | |
264 | close_nointr_nofail(fd); | |
265 | ||
266 | return r; | |
267 | } |