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e83bebef LP |
1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2015 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
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 | |
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 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
4f5dd394 | 22 | #include <sys/mount.h> |
07630cea | 23 | #include <linux/magic.h> |
e83bebef | 24 | |
b5efdb8a | 25 | #include "alloc-util.h" |
4f5dd394 LP |
26 | #include "cgroup-util.h" |
27 | #include "escape.h" | |
f4f15635 | 28 | #include "fs-util.h" |
e83bebef | 29 | #include "label.h" |
4f5dd394 | 30 | #include "mkdir.h" |
4349cd7c | 31 | #include "mount-util.h" |
6bedfcbb LP |
32 | #include "nspawn-mount.h" |
33 | #include "parse-util.h" | |
4f5dd394 LP |
34 | #include "path-util.h" |
35 | #include "rm-rf.h" | |
e83bebef | 36 | #include "set.h" |
8fcde012 | 37 | #include "stat-util.h" |
07630cea | 38 | #include "string-util.h" |
4f5dd394 | 39 | #include "strv.h" |
ee104e11 | 40 | #include "user-util.h" |
4f5dd394 | 41 | #include "util.h" |
e83bebef LP |
42 | |
43 | CustomMount* custom_mount_add(CustomMount **l, unsigned *n, CustomMountType t) { | |
44 | CustomMount *c, *ret; | |
45 | ||
46 | assert(l); | |
47 | assert(n); | |
48 | assert(t >= 0); | |
49 | assert(t < _CUSTOM_MOUNT_TYPE_MAX); | |
50 | ||
51 | c = realloc(*l, (*n + 1) * sizeof(CustomMount)); | |
52 | if (!c) | |
53 | return NULL; | |
54 | ||
55 | *l = c; | |
56 | ret = *l + *n; | |
57 | (*n)++; | |
58 | ||
59 | *ret = (CustomMount) { .type = t }; | |
60 | ||
61 | return ret; | |
62 | } | |
63 | ||
64 | void custom_mount_free_all(CustomMount *l, unsigned n) { | |
65 | unsigned i; | |
66 | ||
67 | for (i = 0; i < n; i++) { | |
68 | CustomMount *m = l + i; | |
69 | ||
70 | free(m->source); | |
71 | free(m->destination); | |
72 | free(m->options); | |
73 | ||
74 | if (m->work_dir) { | |
75 | (void) rm_rf(m->work_dir, REMOVE_ROOT|REMOVE_PHYSICAL); | |
76 | free(m->work_dir); | |
77 | } | |
78 | ||
79 | strv_free(m->lower); | |
80 | } | |
81 | ||
82 | free(l); | |
83 | } | |
84 | ||
85 | int custom_mount_compare(const void *a, const void *b) { | |
86 | const CustomMount *x = a, *y = b; | |
87 | int r; | |
88 | ||
89 | r = path_compare(x->destination, y->destination); | |
90 | if (r != 0) | |
91 | return r; | |
92 | ||
93 | if (x->type < y->type) | |
94 | return -1; | |
95 | if (x->type > y->type) | |
96 | return 1; | |
97 | ||
98 | return 0; | |
99 | } | |
100 | ||
101 | int bind_mount_parse(CustomMount **l, unsigned *n, const char *s, bool read_only) { | |
102 | _cleanup_free_ char *source = NULL, *destination = NULL, *opts = NULL; | |
103 | const char *p = s; | |
104 | CustomMount *m; | |
105 | int r; | |
106 | ||
107 | assert(l); | |
108 | assert(n); | |
109 | ||
110 | r = extract_many_words(&p, ":", EXTRACT_DONT_COALESCE_SEPARATORS, &source, &destination, NULL); | |
111 | if (r < 0) | |
112 | return r; | |
113 | if (r == 0) | |
114 | return -EINVAL; | |
115 | ||
116 | if (r == 1) { | |
117 | destination = strdup(source); | |
118 | if (!destination) | |
119 | return -ENOMEM; | |
120 | } | |
121 | ||
122 | if (r == 2 && !isempty(p)) { | |
123 | opts = strdup(p); | |
124 | if (!opts) | |
125 | return -ENOMEM; | |
126 | } | |
127 | ||
128 | if (!path_is_absolute(source)) | |
129 | return -EINVAL; | |
130 | ||
131 | if (!path_is_absolute(destination)) | |
132 | return -EINVAL; | |
133 | ||
134 | m = custom_mount_add(l, n, CUSTOM_MOUNT_BIND); | |
135 | if (!m) | |
136 | return log_oom(); | |
137 | ||
138 | m->source = source; | |
139 | m->destination = destination; | |
140 | m->read_only = read_only; | |
141 | m->options = opts; | |
142 | ||
143 | source = destination = opts = NULL; | |
144 | return 0; | |
145 | } | |
146 | ||
147 | int tmpfs_mount_parse(CustomMount **l, unsigned *n, const char *s) { | |
148 | _cleanup_free_ char *path = NULL, *opts = NULL; | |
149 | const char *p = s; | |
150 | CustomMount *m; | |
151 | int r; | |
152 | ||
153 | assert(l); | |
154 | assert(n); | |
155 | assert(s); | |
156 | ||
157 | r = extract_first_word(&p, &path, ":", EXTRACT_DONT_COALESCE_SEPARATORS); | |
158 | if (r < 0) | |
159 | return r; | |
160 | if (r == 0) | |
161 | return -EINVAL; | |
162 | ||
163 | if (isempty(p)) | |
164 | opts = strdup("mode=0755"); | |
165 | else | |
166 | opts = strdup(p); | |
167 | if (!opts) | |
168 | return -ENOMEM; | |
169 | ||
170 | if (!path_is_absolute(path)) | |
171 | return -EINVAL; | |
172 | ||
173 | m = custom_mount_add(l, n, CUSTOM_MOUNT_TMPFS); | |
174 | if (!m) | |
175 | return -ENOMEM; | |
176 | ||
177 | m->destination = path; | |
178 | m->options = opts; | |
179 | ||
180 | path = opts = NULL; | |
181 | return 0; | |
182 | } | |
183 | ||
184 | static int tmpfs_patch_options( | |
185 | const char *options, | |
186 | bool userns, uid_t uid_shift, uid_t uid_range, | |
187 | const char *selinux_apifs_context, | |
188 | char **ret) { | |
189 | ||
190 | char *buf = NULL; | |
191 | ||
192 | if (userns && uid_shift != 0) { | |
193 | assert(uid_shift != UID_INVALID); | |
194 | ||
195 | if (options) | |
196 | (void) asprintf(&buf, "%s,uid=" UID_FMT ",gid=" UID_FMT, options, uid_shift, uid_shift); | |
197 | else | |
198 | (void) asprintf(&buf, "uid=" UID_FMT ",gid=" UID_FMT, uid_shift, uid_shift); | |
199 | if (!buf) | |
200 | return -ENOMEM; | |
201 | ||
202 | options = buf; | |
203 | } | |
204 | ||
205 | #ifdef HAVE_SELINUX | |
206 | if (selinux_apifs_context) { | |
207 | char *t; | |
208 | ||
209 | if (options) | |
210 | t = strjoin(options, ",context=\"", selinux_apifs_context, "\"", NULL); | |
211 | else | |
212 | t = strjoin("context=\"", selinux_apifs_context, "\"", NULL); | |
213 | if (!t) { | |
214 | free(buf); | |
215 | return -ENOMEM; | |
216 | } | |
217 | ||
218 | free(buf); | |
219 | buf = t; | |
220 | } | |
221 | #endif | |
222 | ||
223 | *ret = buf; | |
224 | return !!buf; | |
225 | } | |
226 | ||
d8fc6a00 LP |
227 | int mount_sysfs(const char *dest) { |
228 | const char *full, *top, *x; | |
d1678248 | 229 | int r; |
d8fc6a00 LP |
230 | |
231 | top = prefix_roota(dest, "/sys"); | |
d1678248 ILG |
232 | r = path_check_fstype(top, SYSFS_MAGIC); |
233 | if (r < 0) | |
234 | return log_error_errno(r, "Failed to determine filesystem type of %s: %m", top); | |
235 | /* /sys might already be mounted as sysfs by the outer child in the | |
236 | * !netns case. In this case, it's all good. Don't touch it because we | |
237 | * don't have the right to do so, see https://github.com/systemd/systemd/issues/1555. | |
238 | */ | |
239 | if (r > 0) | |
240 | return 0; | |
241 | ||
d8fc6a00 LP |
242 | full = prefix_roota(top, "/full"); |
243 | ||
244 | (void) mkdir(full, 0755); | |
245 | ||
246 | if (mount("sysfs", full, "sysfs", MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV, NULL) < 0) | |
247 | return log_error_errno(errno, "Failed to mount sysfs to %s: %m", full); | |
248 | ||
249 | FOREACH_STRING(x, "block", "bus", "class", "dev", "devices", "kernel") { | |
250 | _cleanup_free_ char *from = NULL, *to = NULL; | |
251 | ||
252 | from = prefix_root(full, x); | |
253 | if (!from) | |
254 | return log_oom(); | |
255 | ||
256 | to = prefix_root(top, x); | |
257 | if (!to) | |
258 | return log_oom(); | |
259 | ||
260 | (void) mkdir(to, 0755); | |
261 | ||
262 | if (mount(from, to, NULL, MS_BIND, NULL) < 0) | |
263 | return log_error_errno(errno, "Failed to mount /sys/%s into place: %m", x); | |
264 | ||
265 | if (mount(NULL, to, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, NULL) < 0) | |
266 | return log_error_errno(errno, "Failed to mount /sys/%s read-only: %m", x); | |
267 | } | |
268 | ||
269 | if (umount(full) < 0) | |
270 | return log_error_errno(errno, "Failed to unmount %s: %m", full); | |
271 | ||
272 | if (rmdir(full) < 0) | |
273 | return log_error_errno(errno, "Failed to remove %s: %m", full); | |
274 | ||
275 | x = prefix_roota(top, "/fs/kdbus"); | |
276 | (void) mkdir(x, 0755); | |
277 | ||
278 | if (mount(NULL, top, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, NULL) < 0) | |
279 | return log_error_errno(errno, "Failed to make %s read-only: %m", top); | |
280 | ||
281 | return 0; | |
282 | } | |
283 | ||
e83bebef | 284 | int mount_all(const char *dest, |
403af78c | 285 | bool use_userns, bool in_userns, |
d1678248 | 286 | bool use_netns, |
403af78c | 287 | uid_t uid_shift, uid_t uid_range, |
e83bebef LP |
288 | const char *selinux_apifs_context) { |
289 | ||
290 | typedef struct MountPoint { | |
291 | const char *what; | |
292 | const char *where; | |
293 | const char *type; | |
294 | const char *options; | |
295 | unsigned long flags; | |
296 | bool fatal; | |
d1678248 ILG |
297 | bool in_userns; |
298 | bool use_netns; | |
e83bebef LP |
299 | } MountPoint; |
300 | ||
301 | static const MountPoint mount_table[] = { | |
d1678248 ILG |
302 | { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true, true, false }, |
303 | { "/proc/sys", "/proc/sys", NULL, NULL, MS_BIND, true, true, false }, /* Bind mount first */ | |
304 | { NULL, "/proc/sys", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, true, true, false }, /* Then, make it r/o */ | |
305 | { "tmpfs", "/sys", "tmpfs", "mode=755", MS_NOSUID|MS_NOEXEC|MS_NODEV, true, false, true }, | |
306 | { "sysfs", "/sys", "sysfs", NULL, MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV, true, false, false }, | |
307 | { "tmpfs", "/dev", "tmpfs", "mode=755", MS_NOSUID|MS_STRICTATIME, true, false, false }, | |
308 | { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true, false, false }, | |
309 | { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true, false, false }, | |
310 | { "tmpfs", "/tmp", "tmpfs", "mode=1777", MS_STRICTATIME, true, false, false }, | |
e83bebef | 311 | #ifdef HAVE_SELINUX |
d1678248 ILG |
312 | { "/sys/fs/selinux", "/sys/fs/selinux", NULL, NULL, MS_BIND, false, false, false }, /* Bind mount first */ |
313 | { NULL, "/sys/fs/selinux", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, false, false, false }, /* Then, make it r/o */ | |
e83bebef LP |
314 | #endif |
315 | }; | |
316 | ||
317 | unsigned k; | |
318 | int r; | |
319 | ||
320 | for (k = 0; k < ELEMENTSOF(mount_table); k++) { | |
321 | _cleanup_free_ char *where = NULL, *options = NULL; | |
322 | const char *o; | |
323 | ||
d1678248 ILG |
324 | if (in_userns != mount_table[k].in_userns) |
325 | continue; | |
326 | ||
327 | if (!use_netns && mount_table[k].use_netns) | |
e83bebef LP |
328 | continue; |
329 | ||
330 | where = prefix_root(dest, mount_table[k].where); | |
331 | if (!where) | |
332 | return log_oom(); | |
333 | ||
334 | r = path_is_mount_point(where, AT_SYMLINK_FOLLOW); | |
335 | if (r < 0 && r != -ENOENT) | |
336 | return log_error_errno(r, "Failed to detect whether %s is a mount point: %m", where); | |
337 | ||
338 | /* Skip this entry if it is not a remount. */ | |
339 | if (mount_table[k].what && r > 0) | |
340 | continue; | |
341 | ||
342 | r = mkdir_p(where, 0755); | |
343 | if (r < 0) { | |
344 | if (mount_table[k].fatal) | |
345 | return log_error_errno(r, "Failed to create directory %s: %m", where); | |
346 | ||
347 | log_warning_errno(r, "Failed to create directory %s: %m", where); | |
348 | continue; | |
349 | } | |
350 | ||
351 | o = mount_table[k].options; | |
352 | if (streq_ptr(mount_table[k].type, "tmpfs")) { | |
403af78c | 353 | r = tmpfs_patch_options(o, use_userns, uid_shift, uid_range, selinux_apifs_context, &options); |
e83bebef LP |
354 | if (r < 0) |
355 | return log_oom(); | |
356 | if (r > 0) | |
357 | o = options; | |
358 | } | |
359 | ||
360 | if (mount(mount_table[k].what, | |
361 | where, | |
362 | mount_table[k].type, | |
363 | mount_table[k].flags, | |
364 | o) < 0) { | |
365 | ||
366 | if (mount_table[k].fatal) | |
367 | return log_error_errno(errno, "mount(%s) failed: %m", where); | |
368 | ||
369 | log_warning_errno(errno, "mount(%s) failed, ignoring: %m", where); | |
370 | } | |
371 | } | |
372 | ||
373 | return 0; | |
374 | } | |
375 | ||
376 | static int parse_mount_bind_options(const char *options, unsigned long *mount_flags, char **mount_opts) { | |
377 | const char *p = options; | |
378 | unsigned long flags = *mount_flags; | |
379 | char *opts = NULL; | |
380 | ||
381 | assert(options); | |
382 | ||
383 | for (;;) { | |
384 | _cleanup_free_ char *word = NULL; | |
385 | int r = extract_first_word(&p, &word, ",", 0); | |
386 | if (r < 0) | |
387 | return log_error_errno(r, "Failed to extract mount option: %m"); | |
388 | if (r == 0) | |
389 | break; | |
390 | ||
391 | if (streq(word, "rbind")) | |
392 | flags |= MS_REC; | |
393 | else if (streq(word, "norbind")) | |
394 | flags &= ~MS_REC; | |
395 | else { | |
396 | log_error("Invalid bind mount option: %s", word); | |
397 | return -EINVAL; | |
398 | } | |
399 | } | |
400 | ||
401 | *mount_flags = flags; | |
402 | /* in the future mount_opts will hold string options for mount(2) */ | |
403 | *mount_opts = opts; | |
404 | ||
405 | return 0; | |
406 | } | |
407 | ||
408 | static int mount_bind(const char *dest, CustomMount *m) { | |
409 | struct stat source_st, dest_st; | |
410 | const char *where; | |
411 | unsigned long mount_flags = MS_BIND | MS_REC; | |
412 | _cleanup_free_ char *mount_opts = NULL; | |
413 | int r; | |
414 | ||
415 | assert(m); | |
416 | ||
417 | if (m->options) { | |
418 | r = parse_mount_bind_options(m->options, &mount_flags, &mount_opts); | |
419 | if (r < 0) | |
420 | return r; | |
421 | } | |
422 | ||
423 | if (stat(m->source, &source_st) < 0) | |
424 | return log_error_errno(errno, "Failed to stat %s: %m", m->source); | |
425 | ||
426 | where = prefix_roota(dest, m->destination); | |
427 | ||
428 | if (stat(where, &dest_st) >= 0) { | |
429 | if (S_ISDIR(source_st.st_mode) && !S_ISDIR(dest_st.st_mode)) { | |
430 | log_error("Cannot bind mount directory %s on file %s.", m->source, where); | |
431 | return -EINVAL; | |
432 | } | |
433 | ||
434 | if (!S_ISDIR(source_st.st_mode) && S_ISDIR(dest_st.st_mode)) { | |
435 | log_error("Cannot bind mount file %s on directory %s.", m->source, where); | |
436 | return -EINVAL; | |
437 | } | |
438 | ||
439 | } else if (errno == ENOENT) { | |
440 | r = mkdir_parents_label(where, 0755); | |
441 | if (r < 0) | |
442 | return log_error_errno(r, "Failed to make parents of %s: %m", where); | |
443 | } else { | |
e1427b13 | 444 | return log_error_errno(errno, "Failed to stat %s: %m", where); |
e83bebef LP |
445 | } |
446 | ||
447 | /* Create the mount point. Any non-directory file can be | |
448 | * mounted on any non-directory file (regular, fifo, socket, | |
449 | * char, block). | |
450 | */ | |
451 | if (S_ISDIR(source_st.st_mode)) | |
452 | r = mkdir_label(where, 0755); | |
453 | else | |
454 | r = touch(where); | |
455 | if (r < 0 && r != -EEXIST) | |
456 | return log_error_errno(r, "Failed to create mount point %s: %m", where); | |
457 | ||
458 | if (mount(m->source, where, NULL, mount_flags, mount_opts) < 0) | |
459 | return log_error_errno(errno, "mount(%s) failed: %m", where); | |
460 | ||
461 | if (m->read_only) { | |
462 | r = bind_remount_recursive(where, true); | |
463 | if (r < 0) | |
464 | return log_error_errno(r, "Read-only bind mount failed: %m"); | |
465 | } | |
466 | ||
467 | return 0; | |
468 | } | |
469 | ||
470 | static int mount_tmpfs( | |
471 | const char *dest, | |
472 | CustomMount *m, | |
473 | bool userns, uid_t uid_shift, uid_t uid_range, | |
474 | const char *selinux_apifs_context) { | |
475 | ||
476 | const char *where, *options; | |
477 | _cleanup_free_ char *buf = NULL; | |
478 | int r; | |
479 | ||
480 | assert(dest); | |
481 | assert(m); | |
482 | ||
483 | where = prefix_roota(dest, m->destination); | |
484 | ||
485 | r = mkdir_p_label(where, 0755); | |
486 | if (r < 0 && r != -EEXIST) | |
487 | return log_error_errno(r, "Creating mount point for tmpfs %s failed: %m", where); | |
488 | ||
489 | r = tmpfs_patch_options(m->options, userns, uid_shift, uid_range, selinux_apifs_context, &buf); | |
490 | if (r < 0) | |
491 | return log_oom(); | |
492 | options = r > 0 ? buf : m->options; | |
493 | ||
494 | if (mount("tmpfs", where, "tmpfs", MS_NODEV|MS_STRICTATIME, options) < 0) | |
495 | return log_error_errno(errno, "tmpfs mount to %s failed: %m", where); | |
496 | ||
497 | return 0; | |
498 | } | |
499 | ||
500 | static char *joined_and_escaped_lower_dirs(char * const *lower) { | |
501 | _cleanup_strv_free_ char **sv = NULL; | |
502 | ||
503 | sv = strv_copy(lower); | |
504 | if (!sv) | |
505 | return NULL; | |
506 | ||
507 | strv_reverse(sv); | |
508 | ||
509 | if (!strv_shell_escape(sv, ",:")) | |
510 | return NULL; | |
511 | ||
512 | return strv_join(sv, ":"); | |
513 | } | |
514 | ||
515 | static int mount_overlay(const char *dest, CustomMount *m) { | |
516 | _cleanup_free_ char *lower = NULL; | |
517 | const char *where, *options; | |
518 | int r; | |
519 | ||
520 | assert(dest); | |
521 | assert(m); | |
522 | ||
523 | where = prefix_roota(dest, m->destination); | |
524 | ||
525 | r = mkdir_label(where, 0755); | |
526 | if (r < 0 && r != -EEXIST) | |
527 | return log_error_errno(r, "Creating mount point for overlay %s failed: %m", where); | |
528 | ||
529 | (void) mkdir_p_label(m->source, 0755); | |
530 | ||
531 | lower = joined_and_escaped_lower_dirs(m->lower); | |
532 | if (!lower) | |
533 | return log_oom(); | |
534 | ||
535 | if (m->read_only) { | |
536 | _cleanup_free_ char *escaped_source = NULL; | |
537 | ||
538 | escaped_source = shell_escape(m->source, ",:"); | |
539 | if (!escaped_source) | |
540 | return log_oom(); | |
541 | ||
542 | options = strjoina("lowerdir=", escaped_source, ":", lower); | |
543 | } else { | |
544 | _cleanup_free_ char *escaped_source = NULL, *escaped_work_dir = NULL; | |
545 | ||
546 | assert(m->work_dir); | |
547 | (void) mkdir_label(m->work_dir, 0700); | |
548 | ||
549 | escaped_source = shell_escape(m->source, ",:"); | |
550 | if (!escaped_source) | |
551 | return log_oom(); | |
552 | escaped_work_dir = shell_escape(m->work_dir, ",:"); | |
553 | if (!escaped_work_dir) | |
554 | return log_oom(); | |
555 | ||
556 | options = strjoina("lowerdir=", lower, ",upperdir=", escaped_source, ",workdir=", escaped_work_dir); | |
557 | } | |
558 | ||
559 | if (mount("overlay", where, "overlay", m->read_only ? MS_RDONLY : 0, options) < 0) | |
560 | return log_error_errno(errno, "overlay mount to %s failed: %m", where); | |
561 | ||
562 | return 0; | |
563 | } | |
564 | ||
565 | int mount_custom( | |
566 | const char *dest, | |
567 | CustomMount *mounts, unsigned n, | |
568 | bool userns, uid_t uid_shift, uid_t uid_range, | |
569 | const char *selinux_apifs_context) { | |
570 | ||
571 | unsigned i; | |
572 | int r; | |
573 | ||
574 | assert(dest); | |
575 | ||
576 | for (i = 0; i < n; i++) { | |
577 | CustomMount *m = mounts + i; | |
578 | ||
579 | switch (m->type) { | |
580 | ||
581 | case CUSTOM_MOUNT_BIND: | |
582 | r = mount_bind(dest, m); | |
583 | break; | |
584 | ||
585 | case CUSTOM_MOUNT_TMPFS: | |
586 | r = mount_tmpfs(dest, m, userns, uid_shift, uid_range, selinux_apifs_context); | |
587 | break; | |
588 | ||
589 | case CUSTOM_MOUNT_OVERLAY: | |
590 | r = mount_overlay(dest, m); | |
591 | break; | |
592 | ||
593 | default: | |
594 | assert_not_reached("Unknown custom mount type"); | |
595 | } | |
596 | ||
597 | if (r < 0) | |
598 | return r; | |
599 | } | |
600 | ||
601 | return 0; | |
602 | } | |
603 | ||
604 | static int mount_legacy_cgroup_hierarchy(const char *dest, const char *controller, const char *hierarchy, bool read_only) { | |
605 | char *to; | |
606 | int r; | |
607 | ||
ee30f6ac | 608 | to = strjoina(strempty(dest), "/sys/fs/cgroup/", hierarchy); |
e83bebef LP |
609 | |
610 | r = path_is_mount_point(to, 0); | |
611 | if (r < 0 && r != -ENOENT) | |
612 | return log_error_errno(r, "Failed to determine if %s is mounted already: %m", to); | |
613 | if (r > 0) | |
614 | return 0; | |
615 | ||
616 | mkdir_p(to, 0755); | |
617 | ||
618 | /* The superblock mount options of the mount point need to be | |
619 | * identical to the hosts', and hence writable... */ | |
620 | if (mount("cgroup", to, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, controller) < 0) | |
621 | return log_error_errno(errno, "Failed to mount to %s: %m", to); | |
622 | ||
623 | /* ... hence let's only make the bind mount read-only, not the | |
624 | * superblock. */ | |
625 | if (read_only) { | |
626 | if (mount(NULL, to, NULL, MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, NULL) < 0) | |
627 | return log_error_errno(errno, "Failed to remount %s read-only: %m", to); | |
628 | } | |
629 | return 1; | |
630 | } | |
631 | ||
632 | static int mount_legacy_cgroups( | |
633 | const char *dest, | |
634 | bool userns, uid_t uid_shift, uid_t uid_range, | |
635 | const char *selinux_apifs_context) { | |
636 | ||
637 | _cleanup_set_free_free_ Set *controllers = NULL; | |
638 | const char *cgroup_root; | |
639 | int r; | |
640 | ||
641 | cgroup_root = prefix_roota(dest, "/sys/fs/cgroup"); | |
642 | ||
d8fc6a00 LP |
643 | (void) mkdir_p(cgroup_root, 0755); |
644 | ||
e83bebef LP |
645 | /* Mount a tmpfs to /sys/fs/cgroup if it's not mounted there yet. */ |
646 | r = path_is_mount_point(cgroup_root, AT_SYMLINK_FOLLOW); | |
647 | if (r < 0) | |
648 | return log_error_errno(r, "Failed to determine if /sys/fs/cgroup is already mounted: %m"); | |
649 | if (r == 0) { | |
650 | _cleanup_free_ char *options = NULL; | |
651 | ||
652 | r = tmpfs_patch_options("mode=755", userns, uid_shift, uid_range, selinux_apifs_context, &options); | |
653 | if (r < 0) | |
654 | return log_oom(); | |
655 | ||
656 | if (mount("tmpfs", cgroup_root, "tmpfs", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME, options) < 0) | |
657 | return log_error_errno(errno, "Failed to mount /sys/fs/cgroup: %m"); | |
658 | } | |
659 | ||
660 | if (cg_unified() > 0) | |
661 | goto skip_controllers; | |
662 | ||
663 | controllers = set_new(&string_hash_ops); | |
664 | if (!controllers) | |
665 | return log_oom(); | |
666 | ||
667 | r = cg_kernel_controllers(controllers); | |
668 | if (r < 0) | |
669 | return log_error_errno(r, "Failed to determine cgroup controllers: %m"); | |
670 | ||
671 | for (;;) { | |
672 | _cleanup_free_ char *controller = NULL, *origin = NULL, *combined = NULL; | |
673 | ||
674 | controller = set_steal_first(controllers); | |
675 | if (!controller) | |
676 | break; | |
677 | ||
678 | origin = prefix_root("/sys/fs/cgroup/", controller); | |
679 | if (!origin) | |
680 | return log_oom(); | |
681 | ||
682 | r = readlink_malloc(origin, &combined); | |
683 | if (r == -EINVAL) { | |
684 | /* Not a symbolic link, but directly a single cgroup hierarchy */ | |
685 | ||
686 | r = mount_legacy_cgroup_hierarchy(dest, controller, controller, true); | |
687 | if (r < 0) | |
688 | return r; | |
689 | ||
690 | } else if (r < 0) | |
691 | return log_error_errno(r, "Failed to read link %s: %m", origin); | |
692 | else { | |
693 | _cleanup_free_ char *target = NULL; | |
694 | ||
695 | target = prefix_root(dest, origin); | |
696 | if (!target) | |
697 | return log_oom(); | |
698 | ||
699 | /* A symbolic link, a combination of controllers in one hierarchy */ | |
700 | ||
701 | if (!filename_is_valid(combined)) { | |
702 | log_warning("Ignoring invalid combined hierarchy %s.", combined); | |
703 | continue; | |
704 | } | |
705 | ||
706 | r = mount_legacy_cgroup_hierarchy(dest, combined, combined, true); | |
707 | if (r < 0) | |
708 | return r; | |
709 | ||
710 | r = symlink_idempotent(combined, target); | |
711 | if (r == -EINVAL) { | |
712 | log_error("Invalid existing symlink for combined hierarchy"); | |
713 | return r; | |
714 | } | |
715 | if (r < 0) | |
716 | return log_error_errno(r, "Failed to create symlink for combined hierarchy: %m"); | |
717 | } | |
718 | } | |
719 | ||
720 | skip_controllers: | |
721 | r = mount_legacy_cgroup_hierarchy(dest, "none,name=systemd,xattr", "systemd", false); | |
722 | if (r < 0) | |
723 | return r; | |
724 | ||
725 | if (mount(NULL, cgroup_root, NULL, MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755") < 0) | |
726 | return log_error_errno(errno, "Failed to remount %s read-only: %m", cgroup_root); | |
727 | ||
728 | return 0; | |
729 | } | |
730 | ||
731 | static int mount_unified_cgroups(const char *dest) { | |
732 | const char *p; | |
733 | int r; | |
734 | ||
735 | assert(dest); | |
736 | ||
88e10572 MT |
737 | p = prefix_roota(dest, "/sys/fs/cgroup"); |
738 | ||
739 | (void) mkdir_p(p, 0755); | |
e83bebef LP |
740 | |
741 | r = path_is_mount_point(p, AT_SYMLINK_FOLLOW); | |
742 | if (r < 0) | |
743 | return log_error_errno(r, "Failed to determine if %s is mounted already: %m", p); | |
744 | if (r > 0) { | |
88e10572 | 745 | p = prefix_roota(dest, "/sys/fs/cgroup/cgroup.procs"); |
e83bebef LP |
746 | if (access(p, F_OK) >= 0) |
747 | return 0; | |
748 | if (errno != ENOENT) | |
749 | return log_error_errno(errno, "Failed to determine if mount point %s contains the unified cgroup hierarchy: %m", p); | |
750 | ||
751 | log_error("%s is already mounted but not a unified cgroup hierarchy. Refusing.", p); | |
752 | return -EINVAL; | |
753 | } | |
754 | ||
755 | if (mount("cgroup", p, "cgroup", MS_NOSUID|MS_NOEXEC|MS_NODEV, "__DEVEL__sane_behavior") < 0) | |
756 | return log_error_errno(errno, "Failed to mount unified cgroup hierarchy to %s: %m", p); | |
757 | ||
758 | return 0; | |
759 | } | |
760 | ||
761 | int mount_cgroups( | |
762 | const char *dest, | |
763 | bool unified_requested, | |
764 | bool userns, uid_t uid_shift, uid_t uid_range, | |
765 | const char *selinux_apifs_context) { | |
766 | ||
767 | if (unified_requested) | |
768 | return mount_unified_cgroups(dest); | |
769 | else | |
770 | return mount_legacy_cgroups(dest, userns, uid_shift, uid_range, selinux_apifs_context); | |
771 | } | |
772 | ||
773 | int mount_systemd_cgroup_writable( | |
774 | const char *dest, | |
775 | bool unified_requested) { | |
776 | ||
777 | _cleanup_free_ char *own_cgroup_path = NULL; | |
778 | const char *systemd_root, *systemd_own; | |
779 | int r; | |
780 | ||
781 | assert(dest); | |
782 | ||
783 | r = cg_pid_get_path(NULL, 0, &own_cgroup_path); | |
784 | if (r < 0) | |
785 | return log_error_errno(r, "Failed to determine our own cgroup path: %m"); | |
786 | ||
787 | /* If we are living in the top-level, then there's nothing to do... */ | |
788 | if (path_equal(own_cgroup_path, "/")) | |
789 | return 0; | |
790 | ||
791 | if (unified_requested) { | |
792 | systemd_own = strjoina(dest, "/sys/fs/cgroup", own_cgroup_path); | |
793 | systemd_root = prefix_roota(dest, "/sys/fs/cgroup"); | |
794 | } else { | |
795 | systemd_own = strjoina(dest, "/sys/fs/cgroup/systemd", own_cgroup_path); | |
796 | systemd_root = prefix_roota(dest, "/sys/fs/cgroup/systemd"); | |
797 | } | |
798 | ||
799 | /* Make our own cgroup a (writable) bind mount */ | |
800 | if (mount(systemd_own, systemd_own, NULL, MS_BIND, NULL) < 0) | |
801 | return log_error_errno(errno, "Failed to turn %s into a bind mount: %m", own_cgroup_path); | |
802 | ||
803 | /* And then remount the systemd cgroup root read-only */ | |
804 | if (mount(NULL, systemd_root, NULL, MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, NULL) < 0) | |
805 | return log_error_errno(errno, "Failed to mount cgroup root read-only: %m"); | |
806 | ||
807 | return 0; | |
808 | } | |
809 | ||
810 | int setup_volatile_state( | |
811 | const char *directory, | |
812 | VolatileMode mode, | |
813 | bool userns, uid_t uid_shift, uid_t uid_range, | |
814 | const char *selinux_apifs_context) { | |
815 | ||
816 | _cleanup_free_ char *buf = NULL; | |
817 | const char *p, *options; | |
818 | int r; | |
819 | ||
820 | assert(directory); | |
821 | ||
822 | if (mode != VOLATILE_STATE) | |
823 | return 0; | |
824 | ||
825 | /* --volatile=state means we simply overmount /var | |
826 | with a tmpfs, and the rest read-only. */ | |
827 | ||
828 | r = bind_remount_recursive(directory, true); | |
829 | if (r < 0) | |
830 | return log_error_errno(r, "Failed to remount %s read-only: %m", directory); | |
831 | ||
832 | p = prefix_roota(directory, "/var"); | |
833 | r = mkdir(p, 0755); | |
834 | if (r < 0 && errno != EEXIST) | |
835 | return log_error_errno(errno, "Failed to create %s: %m", directory); | |
836 | ||
837 | options = "mode=755"; | |
838 | r = tmpfs_patch_options(options, userns, uid_shift, uid_range, selinux_apifs_context, &buf); | |
839 | if (r < 0) | |
840 | return log_oom(); | |
841 | if (r > 0) | |
842 | options = buf; | |
843 | ||
844 | if (mount("tmpfs", p, "tmpfs", MS_STRICTATIME, options) < 0) | |
845 | return log_error_errno(errno, "Failed to mount tmpfs to /var: %m"); | |
846 | ||
847 | return 0; | |
848 | } | |
849 | ||
850 | int setup_volatile( | |
851 | const char *directory, | |
852 | VolatileMode mode, | |
853 | bool userns, uid_t uid_shift, uid_t uid_range, | |
854 | const char *selinux_apifs_context) { | |
855 | ||
856 | bool tmpfs_mounted = false, bind_mounted = false; | |
857 | char template[] = "/tmp/nspawn-volatile-XXXXXX"; | |
858 | _cleanup_free_ char *buf = NULL; | |
859 | const char *f, *t, *options; | |
860 | int r; | |
861 | ||
862 | assert(directory); | |
863 | ||
864 | if (mode != VOLATILE_YES) | |
865 | return 0; | |
866 | ||
867 | /* --volatile=yes means we mount a tmpfs to the root dir, and | |
868 | the original /usr to use inside it, and that read-only. */ | |
869 | ||
870 | if (!mkdtemp(template)) | |
871 | return log_error_errno(errno, "Failed to create temporary directory: %m"); | |
872 | ||
873 | options = "mode=755"; | |
874 | r = tmpfs_patch_options(options, userns, uid_shift, uid_range, selinux_apifs_context, &buf); | |
875 | if (r < 0) | |
876 | return log_oom(); | |
877 | if (r > 0) | |
878 | options = buf; | |
879 | ||
880 | if (mount("tmpfs", template, "tmpfs", MS_STRICTATIME, options) < 0) { | |
881 | r = log_error_errno(errno, "Failed to mount tmpfs for root directory: %m"); | |
882 | goto fail; | |
883 | } | |
884 | ||
885 | tmpfs_mounted = true; | |
886 | ||
887 | f = prefix_roota(directory, "/usr"); | |
888 | t = prefix_roota(template, "/usr"); | |
889 | ||
890 | r = mkdir(t, 0755); | |
891 | if (r < 0 && errno != EEXIST) { | |
892 | r = log_error_errno(errno, "Failed to create %s: %m", t); | |
893 | goto fail; | |
894 | } | |
895 | ||
896 | if (mount(f, t, NULL, MS_BIND|MS_REC, NULL) < 0) { | |
897 | r = log_error_errno(errno, "Failed to create /usr bind mount: %m"); | |
898 | goto fail; | |
899 | } | |
900 | ||
901 | bind_mounted = true; | |
902 | ||
903 | r = bind_remount_recursive(t, true); | |
904 | if (r < 0) { | |
905 | log_error_errno(r, "Failed to remount %s read-only: %m", t); | |
906 | goto fail; | |
907 | } | |
908 | ||
909 | if (mount(template, directory, NULL, MS_MOVE, NULL) < 0) { | |
910 | r = log_error_errno(errno, "Failed to move root mount: %m"); | |
911 | goto fail; | |
912 | } | |
913 | ||
914 | (void) rmdir(template); | |
915 | ||
916 | return 0; | |
917 | ||
918 | fail: | |
919 | if (bind_mounted) | |
920 | (void) umount(t); | |
921 | ||
922 | if (tmpfs_mounted) | |
923 | (void) umount(template); | |
924 | (void) rmdir(template); | |
925 | return r; | |
926 | } | |
927 | ||
928 | VolatileMode volatile_mode_from_string(const char *s) { | |
929 | int b; | |
930 | ||
931 | if (isempty(s)) | |
932 | return _VOLATILE_MODE_INVALID; | |
933 | ||
934 | b = parse_boolean(s); | |
935 | if (b > 0) | |
936 | return VOLATILE_YES; | |
937 | if (b == 0) | |
938 | return VOLATILE_NO; | |
939 | ||
940 | if (streq(s, "state")) | |
941 | return VOLATILE_STATE; | |
942 | ||
943 | return _VOLATILE_MODE_INVALID; | |
944 | } |