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db9ecf05 | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
d7ccca2e | 2 | |
d7ccca2e | 3 | #include <fcntl.h> |
618234a5 | 4 | #include <sched.h> |
d7ccca2e | 5 | #include <sys/mount.h> |
618234a5 | 6 | #include <unistd.h> |
d7ccca2e | 7 | |
618234a5 | 8 | #include "sd-id128.h" |
81527be1 | 9 | |
b5efdb8a | 10 | #include "alloc-util.h" |
3ffd4af2 | 11 | #include "fd-util.h" |
f4f15635 | 12 | #include "fs-util.h" |
910fd145 | 13 | #include "id128-util.h" |
3023f2fe | 14 | #include "io-util.h" |
618234a5 | 15 | #include "log.h" |
3ffd4af2 | 16 | #include "machine-id-setup.h" |
d7ccca2e | 17 | #include "macro.h" |
49e942b2 | 18 | #include "mkdir.h" |
21935150 | 19 | #include "mount-util.h" |
049af8ad | 20 | #include "mountpoint-util.h" |
0cb8e3d1 | 21 | #include "namespace-util.h" |
fe970a8a | 22 | #include "path-util.h" |
0b452006 | 23 | #include "process-util.h" |
8fcde012 | 24 | #include "stat-util.h" |
07630cea | 25 | #include "string-util.h" |
affb60b1 | 26 | #include "umask-util.h" |
618234a5 LP |
27 | #include "util.h" |
28 | #include "virt.h" | |
8d41a963 | 29 | |
4b1afed0 | 30 | static int generate_machine_id(const char *root, sd_id128_t *ret) { |
75f86906 | 31 | const char *dbus_machine_id; |
4b1afed0 LP |
32 | _cleanup_close_ int fd = -1; |
33 | int r; | |
d7ccca2e | 34 | |
4b1afed0 | 35 | assert(ret); |
92f2f92e | 36 | |
d7ccca2e | 37 | /* First, try reading the D-Bus machine id, unless it is a symlink */ |
4b1afed0 | 38 | dbus_machine_id = prefix_roota(root, "/var/lib/dbus/machine-id"); |
92f2f92e | 39 | fd = open(dbus_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); |
8d41a963 | 40 | if (fd >= 0) { |
4b1afed0 | 41 | if (id128_read_fd(fd, ID128_PLAIN, ret) >= 0) { |
c6ac7e4b LP |
42 | log_info("Initializing machine ID from D-Bus machine ID."); |
43 | return 0; | |
d7ccca2e | 44 | } |
4b1afed0 LP |
45 | |
46 | fd = safe_close(fd); | |
d7ccca2e LP |
47 | } |
48 | ||
1f894e68 | 49 | if (isempty(root) && running_in_chroot() <= 0) { |
5dd6d0f8 LP |
50 | /* If that didn't work, see if we are running in a container, |
51 | * and a machine ID was passed in via $container_uuid the way | |
52 | * libvirt/LXC does it */ | |
75f86906 LP |
53 | |
54 | if (detect_container() > 0) { | |
5dd6d0f8 | 55 | _cleanup_free_ char *e = NULL; |
0b36bbc4 | 56 | |
4b1afed0 LP |
57 | if (getenv_for_pid(1, "container_uuid", &e) > 0 && |
58 | sd_id128_from_string(e, ret) >= 0) { | |
59 | log_info("Initializing machine ID from container UUID."); | |
60 | return 0; | |
0b36bbc4 | 61 | } |
5dd6d0f8 | 62 | |
75f86906 LP |
63 | } else if (detect_vm() == VIRTUALIZATION_KVM) { |
64 | ||
5dd6d0f8 LP |
65 | /* If we are not running in a container, see if we are |
66 | * running in qemu/kvm and a machine ID was passed in | |
67 | * via -uuid on the qemu/kvm command line */ | |
68 | ||
4b1afed0 LP |
69 | if (id128_read("/sys/class/dmi/id/product_uuid", ID128_UUID, ret) >= 0) { |
70 | log_info("Initializing machine ID from KVM UUID."); | |
71 | return 0; | |
5dd6d0f8 | 72 | } |
8fa0de65 DJL |
73 | /* on POWER, it's exported here instead */ |
74 | if (id128_read("/sys/firmware/devicetree/base/vm,uuid", ID128_UUID, ret) >= 0) { | |
75 | log_info("Initializing machine ID from KVM UUID."); | |
76 | return 0; | |
77 | } | |
0b36bbc4 | 78 | } |
d4eb120a LP |
79 | } |
80 | ||
d7ccca2e | 81 | /* If that didn't work, generate a random machine id */ |
4b1afed0 | 82 | r = sd_id128_randomize(ret); |
23bbb0de | 83 | if (r < 0) |
5e1ee764 | 84 | return log_error_errno(r, "Failed to generate randomized machine ID: %m"); |
d7ccca2e LP |
85 | |
86 | log_info("Initializing machine ID from random generator."); | |
d7ccca2e LP |
87 | return 0; |
88 | } | |
89 | ||
3023f2fe | 90 | int machine_id_setup(const char *root, bool force_transient, sd_id128_t machine_id, sd_id128_t *ret) { |
c6ac7e4b LP |
91 | const char *etc_machine_id, *run_machine_id; |
92 | _cleanup_close_ int fd = -1; | |
4b1afed0 | 93 | bool writable; |
c6ac7e4b | 94 | int r; |
9496e375 | 95 | |
f5e754e0 | 96 | etc_machine_id = prefix_roota(root, "/etc/machine-id"); |
9496e375 | 97 | |
c6ac7e4b LP |
98 | RUN_WITH_UMASK(0000) { |
99 | /* We create this 0444, to indicate that this isn't really | |
100 | * something you should ever modify. Of course, since the file | |
101 | * will be owned by root it doesn't matter much, but maybe | |
102 | * people look. */ | |
9496e375 | 103 | |
4b1afed0 | 104 | (void) mkdir_parents(etc_machine_id, 0755); |
c6ac7e4b LP |
105 | fd = open(etc_machine_id, O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444); |
106 | if (fd < 0) { | |
107 | int old_errno = errno; | |
108 | ||
109 | fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY); | |
110 | if (fd < 0) { | |
111 | if (old_errno == EROFS && errno == ENOENT) | |
d49a7143 | 112 | return log_error_errno(errno, |
c6ac7e4b LP |
113 | "System cannot boot: Missing /etc/machine-id and /etc is mounted read-only.\n" |
114 | "Booting up is supported only when:\n" | |
115 | "1) /etc/machine-id exists and is populated.\n" | |
116 | "2) /etc/machine-id exists and is empty.\n" | |
117 | "3) /etc/machine-id is missing and /etc is writable.\n"); | |
118 | else | |
5e1ee764 | 119 | return log_error_errno(errno, "Cannot open %s: %m", etc_machine_id); |
c6ac7e4b | 120 | } |
9496e375 | 121 | |
c6ac7e4b | 122 | writable = false; |
4b1afed0 LP |
123 | } else |
124 | writable = true; | |
c6ac7e4b LP |
125 | } |
126 | ||
4b1afed0 LP |
127 | /* A we got a valid machine ID argument, that's what counts */ |
128 | if (sd_id128_is_null(machine_id)) { | |
9496e375 | 129 | |
4b1afed0 LP |
130 | /* Try to read any existing machine ID */ |
131 | if (id128_read_fd(fd, ID128_PLAIN, ret) >= 0) | |
132 | return 0; | |
c6ac7e4b | 133 | |
4b1afed0 LP |
134 | /* Hmm, so, the id currently stored is not useful, then let's generate one */ |
135 | r = generate_machine_id(root, &machine_id); | |
ee48dbd5 NC |
136 | if (r < 0) |
137 | return r; | |
fcb24270 | 138 | } |
4b1afed0 | 139 | |
fcb24270 | 140 | if (writable) { |
4b1afed0 | 141 | if (lseek(fd, 0, SEEK_SET) == (off_t) -1) |
fcb24270 EV |
142 | return log_error_errno(errno, "Failed to seek %s: %m", etc_machine_id); |
143 | ||
144 | if (ftruncate(fd, 0) < 0) | |
145 | return log_error_errno(errno, "Failed to truncate %s: %m", etc_machine_id); | |
c6ac7e4b | 146 | |
3023f2fe HS |
147 | /* If the caller requested a transient machine-id, write the string "uninitialized\n" to |
148 | * disk and overmount it with a transient file. | |
149 | * | |
150 | * Otherwise write the machine-id directly to disk. */ | |
151 | if (force_transient) { | |
152 | r = loop_write(fd, "uninitialized\n", strlen("uninitialized\n"), false); | |
153 | if (r < 0) | |
154 | return log_error_errno(r, "Failed to write uninitialized %s: %m", etc_machine_id); | |
155 | ||
156 | r = fsync_full(fd); | |
157 | if (r < 0) | |
158 | return log_error_errno(r, "Failed to sync %s: %m", etc_machine_id); | |
159 | } else { | |
160 | r = id128_write_fd(fd, ID128_PLAIN, machine_id, true); | |
161 | if (r < 0) | |
162 | return log_error_errno(r, "Failed to write %s: %m", etc_machine_id); | |
163 | else | |
164 | goto finish; | |
165 | } | |
fcb24270 | 166 | } |
c6ac7e4b LP |
167 | |
168 | fd = safe_close(fd); | |
169 | ||
3023f2fe HS |
170 | /* Hmm, we couldn't or shouldn't write the machine-id to /etc? |
171 | * So let's write it to /run/machine-id as a replacement */ | |
c6ac7e4b | 172 | |
4b1afed0 LP |
173 | run_machine_id = prefix_roota(root, "/run/machine-id"); |
174 | ||
175 | RUN_WITH_UMASK(0022) | |
176 | r = id128_write(run_machine_id, ID128_PLAIN, machine_id, false); | |
177 | if (r < 0) { | |
178 | (void) unlink(run_machine_id); | |
179 | return log_error_errno(r, "Cannot write %s: %m", run_machine_id); | |
c6ac7e4b LP |
180 | } |
181 | ||
182 | /* And now, let's mount it over */ | |
21935150 LP |
183 | r = mount_follow_verbose(LOG_ERR, run_machine_id, etc_machine_id, NULL, MS_BIND, NULL); |
184 | if (r < 0) { | |
185 | (void) unlink(run_machine_id); | |
186 | return r; | |
c6ac7e4b LP |
187 | } |
188 | ||
3023f2fe | 189 | log_full(force_transient ? LOG_DEBUG : LOG_INFO, "Installed transient %s file.", etc_machine_id); |
c6ac7e4b LP |
190 | |
191 | /* Mark the mount read-only */ | |
21935150 LP |
192 | r = mount_follow_verbose(LOG_WARNING, NULL, etc_machine_id, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, NULL); |
193 | if (r < 0) | |
194 | return r; | |
4b1afed0 LP |
195 | |
196 | finish: | |
197 | if (ret) | |
198 | *ret = machine_id; | |
c6ac7e4b LP |
199 | |
200 | return 0; | |
9496e375 DR |
201 | } |
202 | ||
979ef53a DR |
203 | int machine_id_commit(const char *root) { |
204 | _cleanup_close_ int fd = -1, initial_mntns_fd = -1; | |
c261a5d0 | 205 | const char *etc_machine_id, *sync_path; |
15b1248a | 206 | sd_id128_t id; |
979ef53a DR |
207 | int r; |
208 | ||
c261a5d0 HS |
209 | /* Before doing anything, sync everything to ensure any changes by first-boot units are persisted. |
210 | * | |
211 | * First, explicitly sync the file systems we care about and check if it worked. */ | |
212 | FOREACH_STRING(sync_path, "/etc/", "/var/") { | |
213 | r = syncfs_path(AT_FDCWD, sync_path); | |
214 | if (r < 0) | |
215 | return log_error_errno(r, "Cannot sync %s: %m", sync_path); | |
216 | } | |
217 | ||
218 | /* Afterwards, sync() the rest too, but we can't check the return value for these. */ | |
219 | sync(); | |
220 | ||
15b1248a LP |
221 | /* Replaces a tmpfs bind mount of /etc/machine-id by a proper file, atomically. For this, the umount is removed |
222 | * in a mount namespace, a new file is created at the right place. Afterwards the mount is also removed in the | |
223 | * original mount namespace, thus revealing the file that was just created. */ | |
224 | ||
f5e754e0 | 225 | etc_machine_id = prefix_roota(root, "/etc/machine-id"); |
979ef53a | 226 | |
e1873695 | 227 | r = path_is_mount_point(etc_machine_id, NULL, 0); |
979ef53a | 228 | if (r < 0) |
f131770b | 229 | return log_error_errno(r, "Failed to determine whether %s is a mount point: %m", etc_machine_id); |
979ef53a | 230 | if (r == 0) { |
61233823 | 231 | log_debug("%s is not a mount point. Nothing to do.", etc_machine_id); |
979ef53a DR |
232 | return 0; |
233 | } | |
234 | ||
235 | /* Read existing machine-id */ | |
236 | fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY); | |
237 | if (fd < 0) | |
238 | return log_error_errno(errno, "Cannot open %s: %m", etc_machine_id); | |
239 | ||
c6878637 | 240 | r = fd_is_temporary_fs(fd); |
979ef53a DR |
241 | if (r < 0) |
242 | return log_error_errno(r, "Failed to determine whether %s is on a temporary file system: %m", etc_machine_id); | |
baaa35ad ZJS |
243 | if (r == 0) |
244 | return log_error_errno(SYNTHETIC_ERRNO(EROFS), | |
245 | "%s is not on a temporary file system.", | |
246 | etc_machine_id); | |
979ef53a | 247 | |
15b1248a LP |
248 | r = id128_read_fd(fd, ID128_PLAIN, &id); |
249 | if (r < 0) | |
5e1ee764 | 250 | return log_error_errno(r, "We didn't find a valid machine ID in %s: %m", etc_machine_id); |
15b1248a | 251 | |
979ef53a DR |
252 | fd = safe_close(fd); |
253 | ||
254 | /* Store current mount namespace */ | |
671c3419 | 255 | r = namespace_open(0, NULL, &initial_mntns_fd, NULL, NULL, NULL); |
979ef53a DR |
256 | if (r < 0) |
257 | return log_error_errno(r, "Can't fetch current mount namespace: %m"); | |
258 | ||
259 | /* Switch to a new mount namespace, isolate ourself and unmount etc_machine_id in our new namespace */ | |
e2ec9c4d LP |
260 | r = detach_mount_namespace(); |
261 | if (r < 0) | |
262 | return log_error_errno(r, "Failed to set up new mount namespace: %m"); | |
979ef53a | 263 | |
21935150 LP |
264 | r = umount_verbose(LOG_ERR, etc_machine_id, 0); |
265 | if (r < 0) | |
266 | return r; | |
979ef53a DR |
267 | |
268 | /* Update a persistent version of etc_machine_id */ | |
15b1248a | 269 | r = id128_write(etc_machine_id, ID128_PLAIN, id, true); |
979ef53a | 270 | if (r < 0) |
15b1248a | 271 | return log_error_errno(r, "Cannot write %s. This is mandatory to get a persistent machine ID: %m", etc_machine_id); |
979ef53a DR |
272 | |
273 | /* Return to initial namespace and proceed a lazy tmpfs unmount */ | |
671c3419 | 274 | r = namespace_enter(-1, initial_mntns_fd, -1, -1, -1); |
979ef53a DR |
275 | if (r < 0) |
276 | 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); | |
277 | ||
278 | if (umount2(etc_machine_id, MNT_DETACH) < 0) | |
279 | return log_warning_errno(errno, "Failed to unmount transient %s file: %m.\nWe keep that mount until next reboot.", etc_machine_id); | |
280 | ||
281 | return 0; | |
282 | } |