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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> | |
26 | #include <stdlib.h> | |
27 | #include <fcntl.h> | |
28 | #include <sys/mount.h> | |
29 | ||
73f860db | 30 | #include "systemd/sd-id128.h" |
81527be1 | 31 | |
b6e66135 | 32 | #include "machine-id-setup.h" |
d7ccca2e LP |
33 | #include "macro.h" |
34 | #include "util.h" | |
49e942b2 | 35 | #include "mkdir.h" |
d7ccca2e | 36 | #include "log.h" |
d4eb120a | 37 | #include "virt.h" |
a5c32cff | 38 | #include "fileio.h" |
fe970a8a | 39 | #include "path-util.h" |
8d41a963 | 40 | |
34f750b7 | 41 | static int shorten_uuid(char destination[34], const char source[36]) { |
09b967ea LP |
42 | unsigned i, j; |
43 | ||
44 | for (i = 0, j = 0; i < 36 && j < 32; i++) { | |
45 | int t; | |
46 | ||
47 | t = unhexchar(source[i]); | |
48 | if (t < 0) | |
49 | continue; | |
50 | ||
51 | destination[j++] = hexchar(t); | |
52 | } | |
53 | ||
54 | if (i == 36 && j == 32) { | |
55 | destination[32] = '\n'; | |
56 | destination[33] = 0; | |
57 | return 0; | |
58 | } | |
59 | ||
60 | return -EINVAL; | |
61 | } | |
62 | ||
92f2f92e | 63 | static int generate(char id[34], const char *root) { |
87d2c1ff LP |
64 | int fd, r; |
65 | unsigned char *p; | |
66 | sd_id128_t buf; | |
5dd6d0f8 | 67 | char *q; |
d7ccca2e | 68 | ssize_t k; |
5dd6d0f8 | 69 | const char *vm_id, *dbus_machine_id; |
d7ccca2e LP |
70 | |
71 | assert(id); | |
72 | ||
5dd6d0f8 LP |
73 | if (isempty(root)) |
74 | dbus_machine_id = "/var/lib/dbus/machine-id"; | |
75 | else | |
76 | dbus_machine_id = strappenda(root, "/var/lib/dbus/machine-id"); | |
92f2f92e | 77 | |
d7ccca2e | 78 | /* First, try reading the D-Bus machine id, unless it is a symlink */ |
92f2f92e | 79 | fd = open(dbus_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); |
8d41a963 | 80 | if (fd >= 0) { |
aa96c6cb | 81 | k = loop_read(fd, id, 33, false); |
03e334a1 | 82 | safe_close(fd); |
d7ccca2e | 83 | |
aa96c6cb | 84 | if (k == 33 && id[32] == '\n') { |
d7ccca2e | 85 | |
aa96c6cb LP |
86 | id[32] = 0; |
87 | if (id128_is_valid(id)) { | |
88 | id[32] = '\n'; | |
89 | id[33] = 0; | |
90 | ||
91 | log_info("Initializing machine ID from D-Bus machine ID."); | |
92 | return 0; | |
93 | } | |
d7ccca2e LP |
94 | } |
95 | } | |
96 | ||
5dd6d0f8 LP |
97 | if (isempty(root)) { |
98 | /* If that didn't work, see if we are running in a container, | |
99 | * and a machine ID was passed in via $container_uuid the way | |
100 | * libvirt/LXC does it */ | |
101 | r = detect_container(NULL); | |
ab94af92 | 102 | if (r > 0) { |
5dd6d0f8 | 103 | _cleanup_free_ char *e = NULL; |
0b36bbc4 | 104 | |
5dd6d0f8 LP |
105 | r = getenv_for_pid(1, "container_uuid", &e); |
106 | if (r > 0) { | |
107 | if (strlen(e) >= 36) { | |
108 | r = shorten_uuid(id, e); | |
0b36bbc4 | 109 | if (r >= 0) { |
5dd6d0f8 | 110 | log_info("Initializing machine ID from container UUID."); |
0b36bbc4 LP |
111 | return 0; |
112 | } | |
113 | } | |
114 | } | |
5dd6d0f8 LP |
115 | |
116 | } else { | |
117 | /* If we are not running in a container, see if we are | |
118 | * running in qemu/kvm and a machine ID was passed in | |
119 | * via -uuid on the qemu/kvm command line */ | |
120 | ||
121 | r = detect_vm(&vm_id); | |
122 | if (r > 0 && streq(vm_id, "kvm")) { | |
123 | char uuid[37]; | |
124 | ||
125 | fd = open("/sys/class/dmi/id/product_uuid", O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); | |
126 | if (fd >= 0) { | |
127 | k = loop_read(fd, uuid, 36, false); | |
128 | safe_close(fd); | |
129 | ||
130 | if (k >= 36) { | |
131 | r = shorten_uuid(id, uuid); | |
132 | if (r >= 0) { | |
133 | log_info("Initializing machine ID from KVM UUID."); | |
134 | return 0; | |
135 | } | |
136 | } | |
137 | } | |
138 | } | |
0b36bbc4 | 139 | } |
d4eb120a LP |
140 | } |
141 | ||
d7ccca2e | 142 | /* If that didn't work, generate a random machine id */ |
87d2c1ff LP |
143 | r = sd_id128_randomize(&buf); |
144 | if (r < 0) { | |
da927ba9 | 145 | log_error_errno(r, "Failed to open /dev/urandom: %m"); |
87d2c1ff | 146 | return r; |
d7ccca2e LP |
147 | } |
148 | ||
87d2c1ff | 149 | for (p = buf.bytes, q = id; p < buf.bytes + sizeof(buf); p++, q += 2) { |
d7ccca2e LP |
150 | q[0] = hexchar(*p >> 4); |
151 | q[1] = hexchar(*p & 15); | |
152 | } | |
153 | ||
154 | id[32] = '\n'; | |
155 | id[33] = 0; | |
156 | ||
157 | log_info("Initializing machine ID from random generator."); | |
158 | ||
159 | return 0; | |
160 | } | |
161 | ||
92f2f92e | 162 | int machine_id_setup(const char *root) { |
489388fb | 163 | const char *etc_machine_id, *run_machine_id; |
4b73a0c0 | 164 | _cleanup_close_ int fd = -1; |
86fb9ca7 | 165 | bool writable = true; |
d7ccca2e LP |
166 | struct stat st; |
167 | char id[34]; /* 32 + \n + \0 */ | |
489388fb | 168 | int r; |
92f2f92e | 169 | |
489388fb LP |
170 | if (isempty(root)) { |
171 | etc_machine_id = "/etc/machine-id"; | |
172 | run_machine_id = "/run/machine-id"; | |
173 | } else { | |
174 | etc_machine_id = strappenda(root, "/etc/machine-id"); | |
175 | path_kill_slashes((char*) etc_machine_id); | |
92f2f92e | 176 | |
489388fb LP |
177 | run_machine_id = strappenda(root, "/run/machine-id"); |
178 | path_kill_slashes((char*) run_machine_id); | |
179 | } | |
d7ccca2e | 180 | |
5c0d398d LP |
181 | RUN_WITH_UMASK(0000) { |
182 | /* We create this 0444, to indicate that this isn't really | |
183 | * something you should ever modify. Of course, since the file | |
184 | * will be owned by root it doesn't matter much, but maybe | |
185 | * people look. */ | |
186 | ||
3577de7a | 187 | mkdir_parents(etc_machine_id, 0755); |
92f2f92e | 188 | fd = open(etc_machine_id, O_RDWR|O_CREAT|O_CLOEXEC|O_NOCTTY, 0444); |
86fb9ca7 JS |
189 | if (fd < 0) { |
190 | int old_errno = errno; | |
191 | ||
92f2f92e | 192 | fd = open(etc_machine_id, O_RDONLY|O_CLOEXEC|O_NOCTTY); |
5c0d398d | 193 | if (fd < 0) { |
86fb9ca7 JS |
194 | if (old_errno == EROFS && errno == ENOENT) |
195 | log_error("System cannot boot: Missing /etc/machine-id and /etc is mounted read-only.\n" | |
196 | "Booting up is supported only when:\n" | |
197 | "1) /etc/machine-id exists and is populated.\n" | |
198 | "2) /etc/machine-id exists and is empty.\n" | |
199 | "3) /etc/machine-id is missing and /etc is writable.\n"); | |
200 | else | |
201 | log_error("Cannot open %s: %m", etc_machine_id); | |
5c0d398d LP |
202 | return -errno; |
203 | } | |
76526bad | 204 | |
5c0d398d | 205 | writable = false; |
d7ccca2e | 206 | } |
d7ccca2e LP |
207 | } |
208 | ||
d7ccca2e LP |
209 | if (fstat(fd, &st) < 0) { |
210 | log_error("fstat() failed: %m"); | |
4b73a0c0 | 211 | return -errno; |
d7ccca2e LP |
212 | } |
213 | ||
4b73a0c0 | 214 | if (S_ISREG(st.st_mode)) |
aa96c6cb LP |
215 | if (loop_read(fd, id, 33, false) == 33 && id[32] == '\n') { |
216 | id[32] = 0; | |
217 | ||
218 | if (id128_is_valid(id)) | |
219 | return 0; | |
220 | } | |
d7ccca2e LP |
221 | |
222 | /* Hmm, so, the id currently stored is not useful, then let's | |
223 | * generate one */ | |
224 | ||
92f2f92e | 225 | r = generate(id, root); |
8d41a963 | 226 | if (r < 0) |
4b73a0c0 | 227 | return r; |
d7ccca2e LP |
228 | |
229 | if (S_ISREG(st.st_mode) && writable) { | |
230 | lseek(fd, 0, SEEK_SET); | |
231 | ||
4b73a0c0 LP |
232 | if (loop_write(fd, id, 33, false) == 33) |
233 | return 0; | |
d7ccca2e LP |
234 | } |
235 | ||
03e334a1 | 236 | fd = safe_close(fd); |
d7ccca2e LP |
237 | |
238 | /* Hmm, we couldn't write it? So let's write it to | |
6996295f | 239 | * /run/machine-id as a replacement */ |
d7ccca2e | 240 | |
5c0d398d | 241 | RUN_WITH_UMASK(0022) { |
92f2f92e | 242 | r = write_string_file(run_machine_id, id); |
5c0d398d | 243 | } |
8d41a963 | 244 | if (r < 0) { |
da927ba9 | 245 | log_error_errno(r, "Cannot write %s: %m", run_machine_id); |
92f2f92e | 246 | unlink(run_machine_id); |
4b73a0c0 | 247 | return r; |
d7ccca2e LP |
248 | } |
249 | ||
250 | /* And now, let's mount it over */ | |
92f2f92e | 251 | r = mount(run_machine_id, etc_machine_id, NULL, MS_BIND, NULL); |
6996295f | 252 | if (r < 0) { |
92f2f92e GKH |
253 | log_error("Failed to mount %s: %m", etc_machine_id); |
254 | unlink_noerrno(run_machine_id); | |
4b73a0c0 | 255 | return -errno; |
aed5a525 LP |
256 | } |
257 | ||
92f2f92e | 258 | log_info("Installed transient %s file.", etc_machine_id); |
d7ccca2e | 259 | |
4b73a0c0 | 260 | /* Mark the mount read-only */ |
92f2f92e GKH |
261 | if (mount(NULL, etc_machine_id, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, NULL) < 0) |
262 | log_warning("Failed to make transient %s read-only: %m", etc_machine_id); | |
d7ccca2e | 263 | |
4b73a0c0 | 264 | return 0; |
d7ccca2e | 265 | } |