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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 | |
5430f7f2 LP |
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 | |
d7ccca2e LP |
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 | |
5430f7f2 | 16 | Lesser General Public License for more details. |
d7ccca2e | 17 | |
5430f7f2 | 18 | You should have received a copy of the GNU Lesser General Public License |
d7ccca2e LP |
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> | |
d7ccca2e LP |
26 | #include <fcntl.h> |
27 | #include <sys/mount.h> | |
28 | ||
73f860db | 29 | #include "systemd/sd-id128.h" |
81527be1 | 30 | |
b6e66135 | 31 | #include "machine-id-setup.h" |
d7ccca2e LP |
32 | #include "macro.h" |
33 | #include "util.h" | |
49e942b2 | 34 | #include "mkdir.h" |
d7ccca2e | 35 | #include "log.h" |
d4eb120a | 36 | #include "virt.h" |
a5c32cff | 37 | #include "fileio.h" |
fe970a8a | 38 | #include "path-util.h" |
8d41a963 | 39 | |
34f750b7 | 40 | static int shorten_uuid(char destination[34], const char source[36]) { |
09b967ea LP |
41 | unsigned i, j; |
42 | ||
43 | for (i = 0, j = 0; i < 36 && j < 32; i++) { | |
44 | int t; | |
45 | ||
46 | t = unhexchar(source[i]); | |
47 | if (t < 0) | |
48 | continue; | |
49 | ||
50 | destination[j++] = hexchar(t); | |
51 | } | |
52 | ||
53 | if (i == 36 && j == 32) { | |
54 | destination[32] = '\n'; | |
55 | destination[33] = 0; | |
56 | return 0; | |
57 | } | |
58 | ||
59 | return -EINVAL; | |
60 | } | |
61 | ||
92f2f92e | 62 | static int generate(char id[34], const char *root) { |
87d2c1ff LP |
63 | int fd, r; |
64 | unsigned char *p; | |
65 | sd_id128_t buf; | |
5dd6d0f8 | 66 | char *q; |
d7ccca2e | 67 | ssize_t k; |
5dd6d0f8 | 68 | const char *vm_id, *dbus_machine_id; |
d7ccca2e LP |
69 | |
70 | assert(id); | |
71 | ||
5dd6d0f8 LP |
72 | if (isempty(root)) |
73 | dbus_machine_id = "/var/lib/dbus/machine-id"; | |
74 | else | |
63c372cb | 75 | dbus_machine_id = strjoina(root, "/var/lib/dbus/machine-id"); |
92f2f92e | 76 | |
d7ccca2e | 77 | /* First, try reading the D-Bus machine id, unless it is a symlink */ |
92f2f92e | 78 | fd = open(dbus_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); |
8d41a963 | 79 | if (fd >= 0) { |
aa96c6cb | 80 | k = loop_read(fd, id, 33, false); |
03e334a1 | 81 | safe_close(fd); |
d7ccca2e | 82 | |
aa96c6cb | 83 | if (k == 33 && id[32] == '\n') { |
d7ccca2e | 84 | |
aa96c6cb LP |
85 | id[32] = 0; |
86 | if (id128_is_valid(id)) { | |
87 | id[32] = '\n'; | |
88 | id[33] = 0; | |
89 | ||
90 | log_info("Initializing machine ID from D-Bus machine ID."); | |
91 | return 0; | |
92 | } | |
d7ccca2e LP |
93 | } |
94 | } | |
95 | ||
5dd6d0f8 LP |
96 | if (isempty(root)) { |
97 | /* If that didn't work, see if we are running in a container, | |
98 | * and a machine ID was passed in via $container_uuid the way | |
99 | * libvirt/LXC does it */ | |
100 | r = detect_container(NULL); | |
ab94af92 | 101 | if (r > 0) { |
5dd6d0f8 | 102 | _cleanup_free_ char *e = NULL; |
0b36bbc4 | 103 | |
5dd6d0f8 LP |
104 | r = getenv_for_pid(1, "container_uuid", &e); |
105 | if (r > 0) { | |
106 | if (strlen(e) >= 36) { | |
107 | r = shorten_uuid(id, e); | |
0b36bbc4 | 108 | if (r >= 0) { |
5dd6d0f8 | 109 | log_info("Initializing machine ID from container UUID."); |
0b36bbc4 LP |
110 | return 0; |
111 | } | |
112 | } | |
113 | } | |
5dd6d0f8 LP |
114 | |
115 | } else { | |
116 | /* If we are not running in a container, see if we are | |
117 | * running in qemu/kvm and a machine ID was passed in | |
118 | * via -uuid on the qemu/kvm command line */ | |
119 | ||
120 | r = detect_vm(&vm_id); | |
121 | if (r > 0 && streq(vm_id, "kvm")) { | |
122 | char uuid[37]; | |
123 | ||
124 | fd = open("/sys/class/dmi/id/product_uuid", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); | |
125 | if (fd >= 0) { | |
126 | k = loop_read(fd, uuid, 36, false); | |
127 | safe_close(fd); | |
128 | ||
129 | if (k >= 36) { | |
130 | r = shorten_uuid(id, uuid); | |
131 | if (r >= 0) { | |
132 | log_info("Initializing machine ID from KVM UUID."); | |
133 | return 0; | |
134 | } | |
135 | } | |
136 | } | |
137 | } | |
0b36bbc4 | 138 | } |
d4eb120a LP |
139 | } |
140 | ||
d7ccca2e | 141 | /* If that didn't work, generate a random machine id */ |
87d2c1ff | 142 | r = sd_id128_randomize(&buf); |
23bbb0de MS |
143 | if (r < 0) |
144 | return log_error_errno(r, "Failed to open /dev/urandom: %m"); | |
d7ccca2e | 145 | |
87d2c1ff | 146 | for (p = buf.bytes, q = id; p < buf.bytes + sizeof(buf); p++, q += 2) { |
d7ccca2e LP |
147 | q[0] = hexchar(*p >> 4); |
148 | q[1] = hexchar(*p & 15); | |
149 | } | |
150 | ||
151 | id[32] = '\n'; | |
152 | id[33] = 0; | |
153 | ||
154 | log_info("Initializing machine ID from random generator."); | |
155 | ||
156 | return 0; | |
157 | } | |
158 | ||
9496e375 DR |
159 | static int get_valid_machine_id(int fd, char id[34]) { |
160 | char id_to_validate[34]; | |
161 | ||
162 | assert(fd >= 0); | |
163 | assert(id); | |
164 | ||
165 | if (loop_read(fd, id_to_validate, 33, false) == 33 && id_to_validate[32] == '\n') { | |
166 | id_to_validate[32] = 0; | |
167 | ||
168 | if (id128_is_valid(id_to_validate)) { | |
169 | memcpy(id, id_to_validate, 32); | |
170 | id[32] = '\n'; | |
171 | id[33] = 0; | |
172 | return 0; | |
173 | } | |
174 | } | |
175 | ||
176 | return -EINVAL; | |
177 | } | |
178 | ||
179 | static int write_machine_id(int fd, char id[34]) { | |
180 | assert(fd >= 0); | |
181 | assert(id); | |
182 | lseek(fd, 0, SEEK_SET); | |
183 | ||
553acb7b | 184 | if (loop_write(fd, id, 33, false) == 0) |
9496e375 DR |
185 | return 0; |
186 | ||
187 | return -errno; | |
188 | } | |
189 | ||
979ef53a DR |
190 | int machine_id_commit(const char *root) { |
191 | _cleanup_close_ int fd = -1, initial_mntns_fd = -1; | |
192 | const char *etc_machine_id; | |
193 | char id[34]; /* 32 + \n + \0 */ | |
194 | int r; | |
195 | ||
196 | if (isempty(root)) | |
197 | etc_machine_id = "/etc/machine-id"; | |
198 | else { | |
199 | char *x; | |
200 | ||
63c372cb | 201 | x = strjoina(root, "/etc/machine-id"); |
979ef53a DR |
202 | etc_machine_id = path_kill_slashes(x); |
203 | } | |
204 | ||
205 | r = path_is_mount_point(etc_machine_id, false); | |
206 | if (r < 0) | |
f131770b | 207 | return log_error_errno(r, "Failed to determine whether %s is a mount point: %m", etc_machine_id); |
979ef53a DR |
208 | if (r == 0) { |
209 | log_debug("%s is is not a mount point. Nothing to do.", etc_machine_id); | |
210 | return 0; | |
211 | } | |
212 | ||
213 | /* Read existing machine-id */ | |
214 | fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY); | |
215 | if (fd < 0) | |
216 | return log_error_errno(errno, "Cannot open %s: %m", etc_machine_id); | |
217 | ||
218 | r = get_valid_machine_id(fd, id); | |
219 | if (r < 0) | |
220 | return log_error_errno(r, "We didn't find a valid machine ID in %s.", etc_machine_id); | |
221 | ||
222 | r = is_fd_on_temporary_fs(fd); | |
223 | if (r < 0) | |
224 | return log_error_errno(r, "Failed to determine whether %s is on a temporary file system: %m", etc_machine_id); | |
225 | if (r == 0) { | |
226 | log_error("%s is not on a temporary file system.", etc_machine_id); | |
227 | return -EROFS; | |
228 | } | |
229 | ||
230 | fd = safe_close(fd); | |
231 | ||
232 | /* Store current mount namespace */ | |
233 | r = namespace_open(0, NULL, &initial_mntns_fd, NULL, NULL); | |
234 | if (r < 0) | |
235 | return log_error_errno(r, "Can't fetch current mount namespace: %m"); | |
236 | ||
237 | /* Switch to a new mount namespace, isolate ourself and unmount etc_machine_id in our new namespace */ | |
238 | if (unshare(CLONE_NEWNS) < 0) | |
239 | return log_error_errno(errno, "Failed to enter new namespace: %m"); | |
240 | ||
241 | if (mount(NULL, "/", NULL, MS_SLAVE | MS_REC, NULL) < 0) | |
242 | return log_error_errno(errno, "Couldn't make-rslave / mountpoint in our private namespace: %m"); | |
243 | ||
244 | if (umount(etc_machine_id) < 0) | |
245 | return log_error_errno(errno, "Failed to unmount transient %s file in our private namespace: %m", etc_machine_id); | |
246 | ||
247 | /* Update a persistent version of etc_machine_id */ | |
248 | fd = open(etc_machine_id, O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444); | |
249 | if (fd < 0) | |
250 | return log_error_errno(errno, "Cannot open for writing %s. This is mandatory to get a persistent machine-id: %m", etc_machine_id); | |
251 | ||
252 | r = write_machine_id(fd, id); | |
253 | if (r < 0) | |
254 | return log_error_errno(r, "Cannot write %s: %m", etc_machine_id); | |
255 | ||
256 | fd = safe_close(fd); | |
257 | ||
258 | /* Return to initial namespace and proceed a lazy tmpfs unmount */ | |
259 | r = namespace_enter(-1, initial_mntns_fd, -1, -1); | |
260 | if (r < 0) | |
261 | return log_warning_errno(r, "Failed to switch back to initial mount namespace: %m.\nWe'll keep transient %s file until next reboot.", etc_machine_id); | |
262 | ||
263 | if (umount2(etc_machine_id, MNT_DETACH) < 0) | |
264 | return log_warning_errno(errno, "Failed to unmount transient %s file: %m.\nWe keep that mount until next reboot.", etc_machine_id); | |
265 | ||
266 | return 0; | |
267 | } | |
268 | ||
92f2f92e | 269 | int machine_id_setup(const char *root) { |
489388fb | 270 | const char *etc_machine_id, *run_machine_id; |
4b73a0c0 | 271 | _cleanup_close_ int fd = -1; |
86fb9ca7 | 272 | bool writable = true; |
d7ccca2e LP |
273 | struct stat st; |
274 | char id[34]; /* 32 + \n + \0 */ | |
489388fb | 275 | int r; |
92f2f92e | 276 | |
489388fb LP |
277 | if (isempty(root)) { |
278 | etc_machine_id = "/etc/machine-id"; | |
279 | run_machine_id = "/run/machine-id"; | |
280 | } else { | |
3543f821 | 281 | char *x; |
92f2f92e | 282 | |
63c372cb | 283 | x = strjoina(root, "/etc/machine-id"); |
3543f821 LP |
284 | etc_machine_id = path_kill_slashes(x); |
285 | ||
63c372cb | 286 | x = strjoina(root, "/run/machine-id"); |
3543f821 | 287 | run_machine_id = path_kill_slashes(x); |
489388fb | 288 | } |
d7ccca2e | 289 | |
5c0d398d LP |
290 | RUN_WITH_UMASK(0000) { |
291 | /* We create this 0444, to indicate that this isn't really | |
292 | * something you should ever modify. Of course, since the file | |
293 | * will be owned by root it doesn't matter much, but maybe | |
294 | * people look. */ | |
295 | ||
3577de7a | 296 | mkdir_parents(etc_machine_id, 0755); |
92f2f92e | 297 | fd = open(etc_machine_id, O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444); |
86fb9ca7 JS |
298 | if (fd < 0) { |
299 | int old_errno = errno; | |
300 | ||
92f2f92e | 301 | fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY); |
5c0d398d | 302 | if (fd < 0) { |
86fb9ca7 JS |
303 | if (old_errno == EROFS && errno == ENOENT) |
304 | log_error("System cannot boot: Missing /etc/machine-id and /etc is mounted read-only.\n" | |
305 | "Booting up is supported only when:\n" | |
306 | "1) /etc/machine-id exists and is populated.\n" | |
307 | "2) /etc/machine-id exists and is empty.\n" | |
308 | "3) /etc/machine-id is missing and /etc is writable.\n"); | |
309 | else | |
56f64d95 | 310 | log_error_errno(errno, "Cannot open %s: %m", etc_machine_id); |
5c0d398d LP |
311 | return -errno; |
312 | } | |
76526bad | 313 | |
5c0d398d | 314 | writable = false; |
d7ccca2e | 315 | } |
d7ccca2e LP |
316 | } |
317 | ||
4a62c710 MS |
318 | if (fstat(fd, &st) < 0) |
319 | return log_error_errno(errno, "fstat() failed: %m"); | |
d7ccca2e | 320 | |
9496e375 DR |
321 | if (S_ISREG(st.st_mode) && get_valid_machine_id(fd, id) == 0) |
322 | return 0; | |
d7ccca2e LP |
323 | |
324 | /* Hmm, so, the id currently stored is not useful, then let's | |
325 | * generate one */ | |
326 | ||
92f2f92e | 327 | r = generate(id, root); |
8d41a963 | 328 | if (r < 0) |
4b73a0c0 | 329 | return r; |
d7ccca2e | 330 | |
553acb7b | 331 | if (S_ISREG(st.st_mode) && writable) |
9496e375 | 332 | if (write_machine_id(fd, id) == 0) |
4b73a0c0 | 333 | return 0; |
d7ccca2e | 334 | |
03e334a1 | 335 | fd = safe_close(fd); |
d7ccca2e LP |
336 | |
337 | /* Hmm, we couldn't write it? So let's write it to | |
6996295f | 338 | * /run/machine-id as a replacement */ |
d7ccca2e | 339 | |
5c0d398d | 340 | RUN_WITH_UMASK(0022) { |
92f2f92e | 341 | r = write_string_file(run_machine_id, id); |
5c0d398d | 342 | } |
8d41a963 | 343 | if (r < 0) { |
da927ba9 | 344 | log_error_errno(r, "Cannot write %s: %m", run_machine_id); |
92f2f92e | 345 | unlink(run_machine_id); |
4b73a0c0 | 346 | return r; |
d7ccca2e LP |
347 | } |
348 | ||
349 | /* And now, let's mount it over */ | |
92f2f92e | 350 | r = mount(run_machine_id, etc_machine_id, NULL, MS_BIND, NULL); |
6996295f | 351 | if (r < 0) { |
56f64d95 | 352 | log_error_errno(errno, "Failed to mount %s: %m", etc_machine_id); |
92f2f92e | 353 | unlink_noerrno(run_machine_id); |
4b73a0c0 | 354 | return -errno; |
aed5a525 LP |
355 | } |
356 | ||
92f2f92e | 357 | log_info("Installed transient %s file.", etc_machine_id); |
d7ccca2e | 358 | |
4b73a0c0 | 359 | /* Mark the mount read-only */ |
92f2f92e | 360 | if (mount(NULL, etc_machine_id, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, NULL) < 0) |
56f64d95 | 361 | log_warning_errno(errno, "Failed to make transient %s read-only: %m", etc_machine_id); |
d7ccca2e | 362 | |
4b73a0c0 | 363 | return 0; |
d7ccca2e | 364 | } |