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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" |
910fd145 | 12 | #include "id128-util.h" |
3023f2fe | 13 | #include "io-util.h" |
618234a5 | 14 | #include "log.h" |
3ffd4af2 | 15 | #include "machine-id-setup.h" |
d7ccca2e | 16 | #include "macro.h" |
49e942b2 | 17 | #include "mkdir.h" |
21935150 | 18 | #include "mount-util.h" |
049af8ad | 19 | #include "mountpoint-util.h" |
0cb8e3d1 | 20 | #include "namespace-util.h" |
fe970a8a | 21 | #include "path-util.h" |
0b452006 | 22 | #include "process-util.h" |
8fcde012 | 23 | #include "stat-util.h" |
07630cea | 24 | #include "string-util.h" |
bf819d3a | 25 | #include "sync-util.h" |
affb60b1 | 26 | #include "umask-util.h" |
618234a5 | 27 | #include "virt.h" |
8d41a963 | 28 | |
4b1afed0 | 29 | static int generate_machine_id(const char *root, sd_id128_t *ret) { |
75f86906 | 30 | const char *dbus_machine_id; |
254d1313 | 31 | _cleanup_close_ int fd = -EBADF; |
4b1afed0 | 32 | int r; |
d7ccca2e | 33 | |
4b1afed0 | 34 | assert(ret); |
92f2f92e | 35 | |
d7ccca2e | 36 | /* First, try reading the D-Bus machine id, unless it is a symlink */ |
4b1afed0 | 37 | dbus_machine_id = prefix_roota(root, "/var/lib/dbus/machine-id"); |
92f2f92e | 38 | fd = open(dbus_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); |
8d41a963 | 39 | if (fd >= 0) { |
057bf780 | 40 | if (id128_read_fd(fd, ID128_FORMAT_PLAIN, ret) >= 0) { |
c6ac7e4b LP |
41 | log_info("Initializing machine ID from D-Bus machine ID."); |
42 | return 0; | |
d7ccca2e | 43 | } |
4b1afed0 LP |
44 | |
45 | fd = safe_close(fd); | |
d7ccca2e LP |
46 | } |
47 | ||
1f894e68 | 48 | if (isempty(root) && running_in_chroot() <= 0) { |
5dd6d0f8 LP |
49 | /* If that didn't work, see if we are running in a container, |
50 | * and a machine ID was passed in via $container_uuid the way | |
51 | * libvirt/LXC does it */ | |
75f86906 LP |
52 | |
53 | if (detect_container() > 0) { | |
5dd6d0f8 | 54 | _cleanup_free_ char *e = NULL; |
0b36bbc4 | 55 | |
4b1afed0 LP |
56 | if (getenv_for_pid(1, "container_uuid", &e) > 0 && |
57 | sd_id128_from_string(e, ret) >= 0) { | |
58 | log_info("Initializing machine ID from container UUID."); | |
59 | return 0; | |
0b36bbc4 | 60 | } |
5dd6d0f8 | 61 | |
382a46d1 | 62 | } else if (IN_SET(detect_vm(), VIRTUALIZATION_KVM, VIRTUALIZATION_AMAZON, VIRTUALIZATION_QEMU)) { |
75f86906 | 63 | |
382a46d1 BJ |
64 | /* If we are not running in a container, see if we are running in a VM that provides |
65 | * a system UUID via the SMBIOS/DMI interfaces. Such environments include QEMU/KVM | |
66 | * with the -uuid on the qemu command line or the Amazon EC2 Nitro hypervisor. */ | |
5dd6d0f8 | 67 | |
b4be4ff8 | 68 | if (id128_get_product(ret) >= 0) { |
382a46d1 | 69 | log_info("Initializing machine ID from VM UUID."); |
8fa0de65 DJL |
70 | return 0; |
71 | } | |
0b36bbc4 | 72 | } |
d4eb120a LP |
73 | } |
74 | ||
d7ccca2e | 75 | /* If that didn't work, generate a random machine id */ |
4b1afed0 | 76 | r = sd_id128_randomize(ret); |
23bbb0de | 77 | if (r < 0) |
5e1ee764 | 78 | return log_error_errno(r, "Failed to generate randomized machine ID: %m"); |
d7ccca2e LP |
79 | |
80 | log_info("Initializing machine ID from random generator."); | |
d7ccca2e LP |
81 | return 0; |
82 | } | |
83 | ||
3023f2fe | 84 | int machine_id_setup(const char *root, bool force_transient, sd_id128_t machine_id, sd_id128_t *ret) { |
c6ac7e4b | 85 | const char *etc_machine_id, *run_machine_id; |
254d1313 | 86 | _cleanup_close_ int fd = -EBADF; |
4b1afed0 | 87 | bool writable; |
c6ac7e4b | 88 | int r; |
9496e375 | 89 | |
f5e754e0 | 90 | etc_machine_id = prefix_roota(root, "/etc/machine-id"); |
9496e375 | 91 | |
2053593f | 92 | WITH_UMASK(0000) { |
c6ac7e4b LP |
93 | /* We create this 0444, to indicate that this isn't really |
94 | * something you should ever modify. Of course, since the file | |
95 | * will be owned by root it doesn't matter much, but maybe | |
96 | * people look. */ | |
9496e375 | 97 | |
4b1afed0 | 98 | (void) mkdir_parents(etc_machine_id, 0755); |
c6ac7e4b LP |
99 | fd = open(etc_machine_id, O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444); |
100 | if (fd < 0) { | |
101 | int old_errno = errno; | |
102 | ||
103 | fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY); | |
104 | if (fd < 0) { | |
105 | if (old_errno == EROFS && errno == ENOENT) | |
d49a7143 | 106 | return log_error_errno(errno, |
c6ac7e4b LP |
107 | "System cannot boot: Missing /etc/machine-id and /etc is mounted read-only.\n" |
108 | "Booting up is supported only when:\n" | |
109 | "1) /etc/machine-id exists and is populated.\n" | |
110 | "2) /etc/machine-id exists and is empty.\n" | |
111 | "3) /etc/machine-id is missing and /etc is writable.\n"); | |
112 | else | |
5e1ee764 | 113 | return log_error_errno(errno, "Cannot open %s: %m", etc_machine_id); |
c6ac7e4b | 114 | } |
9496e375 | 115 | |
c6ac7e4b | 116 | writable = false; |
4b1afed0 LP |
117 | } else |
118 | writable = true; | |
c6ac7e4b LP |
119 | } |
120 | ||
4b1afed0 LP |
121 | /* A we got a valid machine ID argument, that's what counts */ |
122 | if (sd_id128_is_null(machine_id)) { | |
9496e375 | 123 | |
4b1afed0 | 124 | /* Try to read any existing machine ID */ |
057bf780 | 125 | if (id128_read_fd(fd, ID128_FORMAT_PLAIN, ret) >= 0) |
4b1afed0 | 126 | return 0; |
c6ac7e4b | 127 | |
4b1afed0 LP |
128 | /* Hmm, so, the id currently stored is not useful, then let's generate one */ |
129 | r = generate_machine_id(root, &machine_id); | |
ee48dbd5 NC |
130 | if (r < 0) |
131 | return r; | |
fcb24270 | 132 | } |
4b1afed0 | 133 | |
fcb24270 | 134 | if (writable) { |
4b1afed0 | 135 | if (lseek(fd, 0, SEEK_SET) == (off_t) -1) |
fcb24270 EV |
136 | return log_error_errno(errno, "Failed to seek %s: %m", etc_machine_id); |
137 | ||
138 | if (ftruncate(fd, 0) < 0) | |
139 | return log_error_errno(errno, "Failed to truncate %s: %m", etc_machine_id); | |
c6ac7e4b | 140 | |
3023f2fe HS |
141 | /* If the caller requested a transient machine-id, write the string "uninitialized\n" to |
142 | * disk and overmount it with a transient file. | |
143 | * | |
144 | * Otherwise write the machine-id directly to disk. */ | |
145 | if (force_transient) { | |
146 | r = loop_write(fd, "uninitialized\n", strlen("uninitialized\n"), false); | |
147 | if (r < 0) | |
148 | return log_error_errno(r, "Failed to write uninitialized %s: %m", etc_machine_id); | |
149 | ||
150 | r = fsync_full(fd); | |
151 | if (r < 0) | |
152 | return log_error_errno(r, "Failed to sync %s: %m", etc_machine_id); | |
153 | } else { | |
b40c8ebd | 154 | r = id128_write_fd(fd, ID128_FORMAT_PLAIN | ID128_SYNC_ON_WRITE, machine_id); |
3023f2fe HS |
155 | if (r < 0) |
156 | return log_error_errno(r, "Failed to write %s: %m", etc_machine_id); | |
157 | else | |
158 | goto finish; | |
159 | } | |
fcb24270 | 160 | } |
c6ac7e4b LP |
161 | |
162 | fd = safe_close(fd); | |
163 | ||
3023f2fe HS |
164 | /* Hmm, we couldn't or shouldn't write the machine-id to /etc? |
165 | * So let's write it to /run/machine-id as a replacement */ | |
c6ac7e4b | 166 | |
4b1afed0 LP |
167 | run_machine_id = prefix_roota(root, "/run/machine-id"); |
168 | ||
2053593f | 169 | WITH_UMASK(0022) |
b40c8ebd | 170 | r = id128_write(run_machine_id, ID128_FORMAT_PLAIN, machine_id); |
4b1afed0 LP |
171 | if (r < 0) { |
172 | (void) unlink(run_machine_id); | |
173 | return log_error_errno(r, "Cannot write %s: %m", run_machine_id); | |
c6ac7e4b LP |
174 | } |
175 | ||
176 | /* And now, let's mount it over */ | |
21935150 LP |
177 | r = mount_follow_verbose(LOG_ERR, run_machine_id, etc_machine_id, NULL, MS_BIND, NULL); |
178 | if (r < 0) { | |
179 | (void) unlink(run_machine_id); | |
180 | return r; | |
c6ac7e4b LP |
181 | } |
182 | ||
3023f2fe | 183 | log_full(force_transient ? LOG_DEBUG : LOG_INFO, "Installed transient %s file.", etc_machine_id); |
c6ac7e4b LP |
184 | |
185 | /* Mark the mount read-only */ | |
21935150 LP |
186 | r = mount_follow_verbose(LOG_WARNING, NULL, etc_machine_id, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, NULL); |
187 | if (r < 0) | |
188 | return r; | |
4b1afed0 LP |
189 | |
190 | finish: | |
191 | if (ret) | |
192 | *ret = machine_id; | |
c6ac7e4b LP |
193 | |
194 | return 0; | |
9496e375 DR |
195 | } |
196 | ||
979ef53a | 197 | int machine_id_commit(const char *root) { |
254d1313 | 198 | _cleanup_close_ int fd = -EBADF, initial_mntns_fd = -EBADF; |
5980d463 | 199 | const char *etc_machine_id; |
15b1248a | 200 | sd_id128_t id; |
979ef53a DR |
201 | int r; |
202 | ||
c261a5d0 HS |
203 | /* Before doing anything, sync everything to ensure any changes by first-boot units are persisted. |
204 | * | |
205 | * First, explicitly sync the file systems we care about and check if it worked. */ | |
206 | FOREACH_STRING(sync_path, "/etc/", "/var/") { | |
207 | r = syncfs_path(AT_FDCWD, sync_path); | |
208 | if (r < 0) | |
209 | return log_error_errno(r, "Cannot sync %s: %m", sync_path); | |
210 | } | |
211 | ||
212 | /* Afterwards, sync() the rest too, but we can't check the return value for these. */ | |
213 | sync(); | |
214 | ||
15b1248a LP |
215 | /* Replaces a tmpfs bind mount of /etc/machine-id by a proper file, atomically. For this, the umount is removed |
216 | * in a mount namespace, a new file is created at the right place. Afterwards the mount is also removed in the | |
217 | * original mount namespace, thus revealing the file that was just created. */ | |
218 | ||
f5e754e0 | 219 | etc_machine_id = prefix_roota(root, "/etc/machine-id"); |
979ef53a | 220 | |
e1873695 | 221 | r = path_is_mount_point(etc_machine_id, NULL, 0); |
979ef53a | 222 | if (r < 0) |
f131770b | 223 | return log_error_errno(r, "Failed to determine whether %s is a mount point: %m", etc_machine_id); |
979ef53a | 224 | if (r == 0) { |
61233823 | 225 | log_debug("%s is not a mount point. Nothing to do.", etc_machine_id); |
979ef53a DR |
226 | return 0; |
227 | } | |
228 | ||
229 | /* Read existing machine-id */ | |
230 | fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY); | |
231 | if (fd < 0) | |
232 | return log_error_errno(errno, "Cannot open %s: %m", etc_machine_id); | |
233 | ||
c6878637 | 234 | r = fd_is_temporary_fs(fd); |
979ef53a DR |
235 | if (r < 0) |
236 | return log_error_errno(r, "Failed to determine whether %s is on a temporary file system: %m", etc_machine_id); | |
baaa35ad ZJS |
237 | if (r == 0) |
238 | return log_error_errno(SYNTHETIC_ERRNO(EROFS), | |
239 | "%s is not on a temporary file system.", | |
240 | etc_machine_id); | |
979ef53a | 241 | |
057bf780 | 242 | r = id128_read_fd(fd, ID128_FORMAT_PLAIN, &id); |
15b1248a | 243 | if (r < 0) |
5e1ee764 | 244 | return log_error_errno(r, "We didn't find a valid machine ID in %s: %m", etc_machine_id); |
15b1248a | 245 | |
979ef53a DR |
246 | fd = safe_close(fd); |
247 | ||
248 | /* Store current mount namespace */ | |
671c3419 | 249 | r = namespace_open(0, NULL, &initial_mntns_fd, NULL, NULL, NULL); |
979ef53a DR |
250 | if (r < 0) |
251 | return log_error_errno(r, "Can't fetch current mount namespace: %m"); | |
252 | ||
253 | /* Switch to a new mount namespace, isolate ourself and unmount etc_machine_id in our new namespace */ | |
e2ec9c4d LP |
254 | r = detach_mount_namespace(); |
255 | if (r < 0) | |
256 | return log_error_errno(r, "Failed to set up new mount namespace: %m"); | |
979ef53a | 257 | |
21935150 LP |
258 | r = umount_verbose(LOG_ERR, etc_machine_id, 0); |
259 | if (r < 0) | |
260 | return r; | |
979ef53a DR |
261 | |
262 | /* Update a persistent version of etc_machine_id */ | |
b40c8ebd | 263 | r = id128_write(etc_machine_id, ID128_FORMAT_PLAIN | ID128_SYNC_ON_WRITE, id); |
979ef53a | 264 | if (r < 0) |
15b1248a | 265 | return log_error_errno(r, "Cannot write %s. This is mandatory to get a persistent machine ID: %m", etc_machine_id); |
979ef53a DR |
266 | |
267 | /* Return to initial namespace and proceed a lazy tmpfs unmount */ | |
671c3419 | 268 | r = namespace_enter(-1, initial_mntns_fd, -1, -1, -1); |
979ef53a DR |
269 | if (r < 0) |
270 | 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); | |
271 | ||
272 | if (umount2(etc_machine_id, MNT_DETACH) < 0) | |
273 | return log_warning_errno(errno, "Failed to unmount transient %s file: %m.\nWe keep that mount until next reboot.", etc_machine_id); | |
274 | ||
275 | return 0; | |
276 | } |