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mount-util: use new mount API for image mount tunnel
[thirdparty/systemd.git] / src / shared / mount-util.c
CommitLineData
db9ecf05 1/* SPDX-License-Identifier: LGPL-2.1-or-later */
4349cd7c 2
11c3a366
TA		 3#include <errno.h>
4#include <stdlib.h>
4349cd7c 5#include <sys/mount.h>
11c3a366 6#include <sys/stat.h>
4349cd7c 7#include <sys/statvfs.h>
11c3a366 8#include <unistd.h>
35fd3558 9#include <linux/loop.h>
3657d3a0 10#if WANT_LINUX_FS_H
35fd3558 11#include <linux/fs.h>
3657d3a0 12#endif
4349cd7c 13
b5efdb8a 14#include "alloc-util.h"
f461a28d 15#include "chase.h"
70599967 16#include "dissect-image.h"
45a68ed3 17#include "exec-util.h"
9e7f941a 18#include "extract-word.h"
4349cd7c
LP		 19#include "fd-util.h"
20#include "fileio.h"
e1873695 21#include "fs-util.h"
e2341b6b 22#include "glyph-util.h"
93cc7779 23#include "hashmap.h"
2e776ed6 24#include "initrd-util.h"
0690160e 25#include "label-util.h"
13dcfe46 26#include "libmount-util.h"
1c092b62 27#include "missing_mount.h"
35fd3558 28#include "missing_syscall.h"
35cd0ba5 29#include "mkdir-label.h"
4349cd7c 30#include "mount-util.h"
049af8ad 31#include "mountpoint-util.h"
2338a175 32#include "namespace-util.h"
4349cd7c
LP		 33#include "parse-util.h"
34#include "path-util.h"
6af52c3a 35#include "process-util.h"
4349cd7c 36#include "set.h"
f63a2c48 37#include "sort-util.h"
28126409 38#include "stat-util.h"
15a5e950 39#include "stdio-util.h"
57c10a56 40#include "string-table.h"
4349cd7c 41#include "string-util.h"
6b7c9f8b 42#include "strv.h"
6af52c3a 43#include "tmpfile-util.h"
70599967 44#include "user-util.h"
4349cd7c 45
84bcb394 46int umount_recursive_full(const char *prefix, int flags, char **keep) {
890c14e3 47 _cleanup_fclose_ FILE *f = NULL;
4349cd7c
LP		 48 int n = 0, r;
49
9d0619de
LP		 50 /* Try to umount everything recursively below a directory. Also, take care of stacked mounts, and
51 * keep unmounting them until they are gone. */
4349cd7c 52
890c14e3
LP		 53 f = fopen("/proc/self/mountinfo", "re"); /* Pin the file, in case we unmount /proc/ as part of the logic here */
54 if (!f)
55 return log_debug_errno(errno, "Failed to open /proc/self/mountinfo: %m");
56
57 for (;;) {
13dcfe46
ZJS		 58 _cleanup_(mnt_free_tablep) struct libmnt_table *table = NULL;
59 _cleanup_(mnt_free_iterp) struct libmnt_iter *iter = NULL;
890c14e3 60 bool again = false;
4349cd7c 61
890c14e3 62 r = libmount_parse("/proc/self/mountinfo", f, &table, &iter);
fdeea3f4 63 if (r < 0)
13dcfe46 64 return log_debug_errno(r, "Failed to parse /proc/self/mountinfo: %m");
35bbbf85 65
4349cd7c 66 for (;;) {
84bcb394 67 bool shall_keep = false;
13dcfe46
ZJS		 68 struct libmnt_fs *fs;
69 const char *path;
4349cd7c 70
13dcfe46
ZJS		 71 r = mnt_table_next_fs(table, iter, &fs);
72 if (r == 1)
73 break;
74 if (r < 0)
75 return log_debug_errno(r, "Failed to get next entry from /proc/self/mountinfo: %m");
4349cd7c 76
13dcfe46
ZJS		 77 path = mnt_fs_get_target(fs);
78 if (!path)
79 continue;
4349cd7c 80
ef742415 81 if (prefix && !path_startswith(path, prefix)) {
62c505e1 82 log_trace("Not unmounting %s, outside of prefix: %s", path, prefix);
4349cd7c 83 continue;
ef742415 84 }
4349cd7c 85
84bcb394
LP		 86 STRV_FOREACH(k, keep)
87 /* Match against anything in the path to the dirs to keep, or below the dirs to keep */
88 if (path_startswith(path, *k) || path_startswith(*k, path)) {
89 shall_keep = true;
90 break;
91 }
92 if (shall_keep) {
93 log_debug("Not unmounting %s, referenced by keep list.", path);
94 continue;
95 }
96
827ea521
LP		 97 if (umount2(path, flags | UMOUNT_NOFOLLOW) < 0) {
98 log_debug_errno(errno, "Failed to umount %s, ignoring: %m", path);
4349cd7c
LP		 99 continue;
100 }
101
30868c1c 102 log_trace("Successfully unmounted %s", path);
6b7c9f8b 103
4349cd7c
LP		 104 again = true;
105 n++;
106
107 break;
108 }
890c14e3
LP		 109
110 if (!again)
111 break;
112
113 rewind(f);
114 }
4349cd7c 115
13dcfe46 116 return n;
4349cd7c
LP		 117}
118
4f5644db
LP		 119#define MS_CONVERTIBLE_FLAGS (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_NOSYMFOLLOW)
120
121static uint64_t ms_flags_to_mount_attr(unsigned long a) {
122 uint64_t f = 0;
123
124 if (FLAGS_SET(a, MS_RDONLY))
125 f |= MOUNT_ATTR_RDONLY;
126
127 if (FLAGS_SET(a, MS_NOSUID))
128 f |= MOUNT_ATTR_NOSUID;
129
130 if (FLAGS_SET(a, MS_NODEV))
131 f |= MOUNT_ATTR_NODEV;
132
133 if (FLAGS_SET(a, MS_NOEXEC))
134 f |= MOUNT_ATTR_NOEXEC;
135
136 if (FLAGS_SET(a, MS_NOSYMFOLLOW))
137 f |= MOUNT_ATTR_NOSYMFOLLOW;
138
139 return f;
140}
141
142static bool skip_mount_set_attr = false;
143
be3f3752 144/* Use this function only if you do not have direct access to /proc/self/mountinfo but the caller can open it
64e82c19
LP		 145 * for you. This is the case when /proc is masked or not mounted. Otherwise, use bind_remount_recursive. */
146int bind_remount_recursive_with_mountinfo(
147 const char *prefix,
148 unsigned long new_flags,
149 unsigned long flags_mask,
6b000af4 150 char **deny_list,
64e82c19
LP		 151 FILE *proc_self_mountinfo) {
152
0289948e 153 _cleanup_fclose_ FILE *proc_self_mountinfo_opened = NULL;
ba8dced2 154 _cleanup_set_free_ Set *done = NULL;
670e8efd 155 unsigned n_tries = 0;
4349cd7c
LP		 156 int r;
157
8403219f 158 assert(prefix);
ac9de0b3 159
874052c5
LP		 160 if ((flags_mask & ~MS_CONVERTIBLE_FLAGS) == 0 && strv_isempty(deny_list) && !skip_mount_set_attr) {
161 /* Let's take a shortcut for all the flags we know how to convert into mount_setattr() flags */
162
163 if (mount_setattr(AT_FDCWD, prefix, AT_SYMLINK_NOFOLLOW|AT_RECURSIVE,
164 &(struct mount_attr) {
165 .attr_set = ms_flags_to_mount_attr(new_flags & flags_mask),
166 .attr_clr = ms_flags_to_mount_attr(~new_flags & flags_mask),
167 }, MOUNT_ATTR_SIZE_VER0) < 0) {
168
169 log_debug_errno(errno, "mount_setattr() failed, falling back to classic remounting: %m");
170
171 /* We fall through to classic behaviour if not supported (i.e. kernel < 5.12). We
172 * also do this for all other kinds of errors since they are so many different, and
173 * mount_setattr() has no graceful mode where it continues despite seeing errors one
174 * some mounts, but we want that. Moreover mount_setattr() only works on the mount
175 * point inode itself, not a non-mount point inode, and we want to support arbitrary
176 * prefixes here. */
177
178 if (ERRNO_IS_NOT_SUPPORTED(errno)) /* if not supported, then don't bother at all anymore */
179 skip_mount_set_attr = true;
180 } else
181 return 0; /* Nice, this worked! */
182 }
183
0289948e
LP		 184 if (!proc_self_mountinfo) {
185 r = fopen_unlocked("/proc/self/mountinfo", "re", &proc_self_mountinfo_opened);
186 if (r < 0)
187 return r;
188
189 proc_self_mountinfo = proc_self_mountinfo_opened;
190 }
191
ddc155b2
TM		 192 /* Recursively remount a directory (and all its submounts) with desired flags (MS_READONLY,
193 * MS_NOSUID, MS_NOEXEC). If the directory is already mounted, we reuse the mount and simply mark it
194 * MS_BIND|MS_RDONLY (or remove the MS_RDONLY for read-write operation), ditto for other flags. If it
195 * isn't we first make it one. Afterwards we apply (or remove) the flags to all submounts we can
196 * access, too. When mounts are stacked on the same mount point we only care for each individual
197 * "top-level" mount on each point, as we cannot influence/access the underlying mounts anyway. We do
198 * not have any effect on future submounts that might get propagated, they might be writable
4b6ef527
LP		 199 * etc. This includes future submounts that have been triggered via autofs. Also note that we can't
200 * operate atomically here. Mounts established while we process the tree might or might not get
201 * noticed and thus might or might not be covered.
6b7c9f8b 202 *
6b000af4
LP		 203 * If the "deny_list" parameter is specified it may contain a list of subtrees to exclude from the
204 * remount operation. Note that we'll ignore the deny list for the top-level path. */
4349cd7c 205
4349cd7c 206 for (;;) {
13dcfe46
ZJS		 207 _cleanup_(mnt_free_tablep) struct libmnt_table *table = NULL;
208 _cleanup_(mnt_free_iterp) struct libmnt_iter *iter = NULL;
ba8dced2 209 _cleanup_hashmap_free_ Hashmap *todo = NULL;
4349cd7c 210 bool top_autofs = false;
4349cd7c 211
670e8efd
LP		 212 if (n_tries++ >= 32) /* Let's not retry this loop forever */
213 return -EBUSY;
214
ac9de0b3 215 rewind(proc_self_mountinfo);
4349cd7c 216
e2857b3d 217 r = libmount_parse("/proc/self/mountinfo", proc_self_mountinfo, &table, &iter);
13dcfe46
ZJS		 218 if (r < 0)
219 return log_debug_errno(r, "Failed to parse /proc/self/mountinfo: %m");
4349cd7c 220
13dcfe46 221 for (;;) {
ba8dced2
LP		 222 _cleanup_free_ char *d = NULL;
223 const char *path, *type, *opts;
224 unsigned long flags = 0;
13dcfe46 225 struct libmnt_fs *fs;
4349cd7c 226
13dcfe46 227 r = mnt_table_next_fs(table, iter, &fs);
d6bfab11 228 if (r == 1) /* EOF */
13dcfe46 229 break;
4349cd7c 230 if (r < 0)
13dcfe46 231 return log_debug_errno(r, "Failed to get next entry from /proc/self/mountinfo: %m");
4349cd7c 232
13dcfe46 233 path = mnt_fs_get_target(fs);
d6bfab11 234 if (!path)
6b7c9f8b
LP		 235 continue;
236
c6111b85 237 if (!path_startswith(path, prefix))
13dcfe46
ZJS		 238 continue;
239
d6bfab11
LP		 240 type = mnt_fs_get_fstype(fs);
241 if (!type)
242 continue;
243
244 /* Let's ignore autofs mounts. If they aren't triggered yet, we want to avoid
245 * triggering them, as we don't make any guarantees for future submounts anyway. If
246 * they are already triggered, then we will find another entry for this. */
247 if (streq(type, "autofs")) {
248 top_autofs = top_autofs || path_equal(path, prefix);
249 continue;
250 }
251
252 if (set_contains(done, path))
253 continue;
254
6b000af4 255 /* Ignore this mount if it is deny-listed, but only if it isn't the top-level mount
13dcfe46 256 * we shall operate on. */
c6111b85 257 if (!path_equal(path, prefix)) {
6b000af4 258 bool deny_listed = false;
6b7c9f8b 259
6b000af4 260 STRV_FOREACH(i, deny_list) {
c6111b85 261 if (path_equal(*i, prefix))
6b7c9f8b
LP		 262 continue;
263
c6111b85 264 if (!path_startswith(*i, prefix))
6b7c9f8b
LP		 265 continue;
266
13dcfe46 267 if (path_startswith(path, *i)) {
6b000af4 268 deny_listed = true;
61f695f4 269 log_trace("Not remounting %s deny-listed by %s, called for %s", path, *i, prefix);
6b7c9f8b
LP		 270 break;
271 }
272 }
d6bfab11 273
6b000af4 274 if (deny_listed)
6b7c9f8b
LP		 275 continue;
276 }
277
ba8dced2
LP		 278 opts = mnt_fs_get_vfs_options(fs);
279 if (opts) {
280 r = mnt_optstr_get_flags(opts, &flags, mnt_get_builtin_optmap(MNT_LINUX_MAP));
281 if (r < 0)
282 log_debug_errno(r, "Could not get flags for '%s', ignoring: %m", path);
283 }
284
285 d = strdup(path);
286 if (!d)
287 return -ENOMEM;
288
289 r = hashmap_ensure_put(&todo, &path_hash_ops_free, d, ULONG_TO_PTR(flags));
290 if (r == -EEXIST)
e0103063
LB		 291 /* If the same path was recorded, but with different mount flags, update it:
292 * it means a mount point is overmounted, and libmount returns the "bottom" (or
293 * older one) first, but we want to reapply the flags from the "top" (or newer
294 * one). See: https://github.com/systemd/systemd/issues/20032
295 * Note that this shouldn't really fail, as we were just told that the key
296 * exists, and it's an update so we want 'd' to be freed immediately. */
297 r = hashmap_update(todo, d, ULONG_TO_PTR(flags));
d6bfab11
LP		 298 if (r < 0)
299 return r;
ba8dced2
LP		 300 if (r > 0)
301 TAKE_PTR(d);
4349cd7c
LP		 302 }
303
5c5753b9
LP		 304 /* Check if the top-level directory was among what we have seen so far. For that check both
305 * 'done' and 'todo'. Also check 'top_autofs' because if the top-level dir is an autofs we'll
306 * not include it in either set but will set this bool. */
c6111b85 307 if (!set_contains(done, prefix) &&
ba8dced2 308 !(top_autofs || hashmap_contains(todo, prefix))) {
5c5753b9 309
6b7c9f8b 310 /* The prefix directory itself is not yet a mount, make it one. */
c6111b85 311 r = mount_nofollow(prefix, prefix, NULL, MS_BIND|MS_REC, NULL);
511a8cfe
LP		 312 if (r < 0)
313 return r;
4349cd7c 314
5c5753b9
LP		 315 /* Immediately rescan, so that we pick up the new mount's flags */
316 continue;
4349cd7c
LP		 317 }
318
5c5753b9 319 /* If we have no submounts to process anymore, we are done */
ba8dced2 320 if (hashmap_isempty(todo))
5c5753b9
LP		 321 return 0;
322
ba8dced2
LP		 323 for (;;) {
324 unsigned long flags;
325 char *x = NULL;
326
327 /* Take the first mount from our list of mounts to still process */
328 flags = PTR_TO_ULONG(hashmap_steal_first_key_and_value(todo, (void**) &x));
329 if (!x)
330 break;
4349cd7c 331
ba8dced2 332 r = set_ensure_consume(&done, &path_hash_ops_free, x);
4c701096 333 if (IN_SET(r, 0, -EEXIST))
ba8dced2 334 continue; /* Already done */
4349cd7c
LP		 335 if (r < 0)
336 return r;
337
ba8dced2
LP		 338 /* Now, remount this with the new flags set, but exclude MS_RELATIME from it. (It's
339 * the default anyway, thus redundant, and in userns we'll get an error if we try to
340 * explicitly enable it) */
341 r = mount_nofollow(NULL, x, NULL, ((flags & ~flags_mask)|MS_BIND|MS_REMOUNT|new_flags) & ~MS_RELATIME, NULL);
065b4774 342 if (r < 0) {
ba8dced2
LP		 343 int q;
344
345 /* OK, so the remount of this entry failed. We'll ultimately ignore this in
346 * almost all cases (there are simply so many reasons why this can fail,
347 * think autofs, NFS, FUSE, …), but let's generate useful debug messages at
348 * the very least. */
349
350 q = path_is_mount_point(x, NULL, 0);
351 if (IN_SET(q, 0, -ENOENT)) {
352 /* Hmm, whaaaa? The mount point is not actually a mount point? Then
353 * it is either obstructed by a later mount or somebody has been
354 * racing against us and removed it. Either way the mount point
355 * doesn't matter to us, let's ignore it hence. */
356 log_debug_errno(r, "Mount point '%s' to remount is not a mount point anymore, ignoring remount failure: %m", x);
357 continue;
358 }
359 if (q < 0) /* Any other error on this? Just log and continue */
360 log_debug_errno(q, "Failed to determine whether '%s' is a mount point or not, ignoring: %m", x);
361
362 if (((flags ^ new_flags) & flags_mask & ~MS_RELATIME) == 0) { /* ignore MS_RELATIME while comparing */
363 log_debug_errno(r, "Couldn't remount '%s', but the flags already match what we want, hence ignoring: %m", x);
364 continue;
365 }
366
367 /* Make this fatal if this is the top-level mount */
368 if (path_equal(x, prefix))
065b4774
LP		 369 return r;
370
ba8dced2
LP		 371 /* If this is not the top-level mount, then handle this gracefully: log but
372 * otherwise ignore. With NFS, FUSE, autofs there are just too many reasons
373 * this might fail without a chance for us to do anything about it, let's
374 * hence be strict on the top-level mount and lenient on the inner ones. */
375 log_debug_errno(r, "Couldn't remount submount '%s' for unexpected reason, ignoring: %m", x);
ef454fd1
YW		 376 continue;
377 }
98df8089 378
30868c1c 379 log_trace("Remounted %s.", x);
4349cd7c
LP		 380 }
381 }
382}
383
7cce68e1
LP		 384int bind_remount_one_with_mountinfo(
385 const char *path,
386 unsigned long new_flags,
387 unsigned long flags_mask,
388 FILE *proc_self_mountinfo) {
389
390 _cleanup_(mnt_free_tablep) struct libmnt_table *table = NULL;
2c5ff8ea
LP		 391 unsigned long flags = 0;
392 struct libmnt_fs *fs;
393 const char *opts;
7cce68e1
LP		 394 int r;
395
396 assert(path);
397 assert(proc_self_mountinfo);
398
4f5644db
LP		 399 if ((flags_mask & ~MS_CONVERTIBLE_FLAGS) == 0 && !skip_mount_set_attr) {
400 /* Let's take a shortcut for all the flags we know how to convert into mount_setattr() flags */
401
402 if (mount_setattr(AT_FDCWD, path, AT_SYMLINK_NOFOLLOW,
403 &(struct mount_attr) {
404 .attr_set = ms_flags_to_mount_attr(new_flags & flags_mask),
405 .attr_clr = ms_flags_to_mount_attr(~new_flags & flags_mask),
406 }, MOUNT_ATTR_SIZE_VER0) < 0) {
407
408 log_debug_errno(errno, "mount_setattr() didn't work, falling back to classic remounting: %m");
409
410 if (ERRNO_IS_NOT_SUPPORTED(errno)) /* if not supported, then don't bother at all anymore */
411 skip_mount_set_attr = true;
412 } else
413 return 0; /* Nice, this worked! */
414 }
415
7cce68e1
LP		 416 rewind(proc_self_mountinfo);
417
418 table = mnt_new_table();
419 if (!table)
420 return -ENOMEM;
421
422 r = mnt_table_parse_stream(table, proc_self_mountinfo, "/proc/self/mountinfo");
423 if (r < 0)
424 return r;
425
2c5ff8ea 426 fs = mnt_table_find_target(table, path, MNT_ITER_FORWARD);
0338df47
LP		 427 if (!fs) {
428 if (laccess(path, F_OK) < 0) /* Hmm, it's not in the mount table, but does it exist at all? */
429 return -errno;
430
2c5ff8ea 431 return -EINVAL; /* Not a mount point we recognize */
0338df47 432 }
2c5ff8ea
LP		 433
434 opts = mnt_fs_get_vfs_options(fs);
435 if (opts) {
436 r = mnt_optstr_get_flags(opts, &flags, mnt_get_builtin_optmap(MNT_LINUX_MAP));
437 if (r < 0)
438 log_debug_errno(r, "Could not get flags for '%s', ignoring: %m", path);
439 }
7cce68e1 440
2c5ff8ea 441 r = mount_nofollow(NULL, path, NULL, ((flags & ~flags_mask)|MS_BIND|MS_REMOUNT|new_flags) & ~MS_RELATIME, NULL);
b23c6a64
LP		 442 if (r < 0) {
443 if (((flags ^ new_flags) & flags_mask & ~MS_RELATIME) != 0) /* Ignore MS_RELATIME again,
444 * since kernel adds it in
445 * everywhere, because it's the
446 * default. */
447 return r;
448
449 /* Let's handle redundant remounts gracefully */
450 log_debug_errno(r, "Failed to remount '%s' but flags already match what we want, ignoring: %m", path);
451 }
7cce68e1
LP		 452
453 return 0;
454}
455
ea0f3289
LP		 456static int mount_switch_root_pivot(int fd_newroot, const char *path) {
457 assert(fd_newroot >= 0);
458 assert(path);
2e776ed6 459
ea0f3289
LP		 460 /* Change into the new rootfs. */
461 if (fchdir(fd_newroot) < 0)
12cc9601 462 return log_debug_errno(errno, "Failed to chdir into new rootfs '%s': %m", path);
2e776ed6 463
2e776ed6
CB		 464 /* Let the kernel tuck the new root under the old one. */
465 if (pivot_root(".", ".") < 0)
466 return log_debug_errno(errno, "Failed to pivot root to new rootfs '%s': %m", path);
467
ea0f3289
LP		 468 /* Get rid of the old root and reveal our brand new root. (This will always operate on the top-most
469 * mount on our cwd, regardless what our current directory actually points to.) */
2e776ed6
CB		 470 if (umount2(".", MNT_DETACH) < 0)
471 return log_debug_errno(errno, "Failed to unmount old rootfs: %m");
472
2e776ed6
CB		 473 return 0;
474}
475
ea0f3289
LP		 476static int mount_switch_root_move(int fd_newroot, const char *path) {
477 assert(fd_newroot >= 0);
478 assert(path);
479
480 /* Change into the new rootfs. */
481 if (fchdir(fd_newroot) < 0)
12cc9601 482 return log_debug_errno(errno, "Failed to chdir into new rootfs '%s': %m", path);
ea0f3289
LP		 483
484 /* Move the new root fs */
485 if (mount(".", "/", NULL, MS_MOVE, NULL) < 0)
57c10a56
CB		 486 return log_debug_errno(errno, "Failed to move new rootfs '%s': %m", path);
487
12cc9601 488 /* Also change root dir */
57c10a56
CB		 489 if (chroot(".") < 0)
490 return log_debug_errno(errno, "Failed to chroot to new rootfs '%s': %m", path);
491
57c10a56
CB		 492 return 0;
493}
494
ea0f3289 495int mount_switch_root_full(const char *path, unsigned long mount_propagation_flag, bool force_ms_move) {
57c10a56 496 _cleanup_close_ int fd_newroot = -EBADF;
6c6eb219 497 int r;
57c10a56
CB		 498
499 assert(path);
9d50f850 500 assert(mount_propagation_flag_is_valid(mount_propagation_flag));
57c10a56
CB		 501
502 fd_newroot = open(path, O_PATH|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW);
503 if (fd_newroot < 0)
504 return log_debug_errno(errno, "Failed to open new rootfs '%s': %m", path);
505
ea0f3289
LP		 506 if (!force_ms_move) {
507 r = mount_switch_root_pivot(fd_newroot, path);
508 if (r < 0) {
509 log_debug_errno(r, "Failed to pivot into new rootfs '%s', will try to use MS_MOVE instead: %m", path);
510 force_ms_move = true;
511 }
512 }
513 if (force_ms_move) {
514 /* Failed to pivot_root() fallback to MS_MOVE. For example, this may happen if the rootfs is
515 * an initramfs in which case pivot_root() isn't supported. */
516 r = mount_switch_root_move(fd_newroot, path);
517 if (r < 0)
518 return log_debug_errno(r, "Failed to switch to new rootfs '%s' with MS_MOVE: %m", path);
57c10a56 519 }
57c10a56 520
9d50f850
YW		 521 /* Finally, let's establish the requested propagation flags. */
522 if (mount_propagation_flag == 0)
523 return 0;
524
525 if (mount(NULL, ".", NULL, mount_propagation_flag | MS_REC, 0) < 0)
57c10a56 526 return log_debug_errno(errno, "Failed to turn new rootfs '%s' into %s mount: %m",
9d50f850 527 mount_propagation_flag_to_string(mount_propagation_flag), path);
57c10a56
CB		 528
529 return 0;
530}
2e776ed6 531
3f2c0bec
LP		 532int repeat_unmount(const char *path, int flags) {
533 bool done = false;
534
535 assert(path);
536
537 /* If there are multiple mounts on a mount point, this
538 * removes them all */
539
540 for (;;) {
541 if (umount2(path, flags) < 0) {
542
543 if (errno == EINVAL)
544 return done;
545
546 return -errno;
547 }
548
549 done = true;
550 }
551}
c4b41707 552
48b747fa
LP		 553int mode_to_inaccessible_node(
554 const char *runtime_dir,
555 mode_t mode,
556 char **ret) {
557
558 /* This function maps a node type to a corresponding inaccessible file node. These nodes are created
559 * during early boot by PID 1. In some cases we lacked the privs to create the character and block
560 * devices (maybe because we run in an userns environment, or miss CAP_SYS_MKNOD, or run with a
561 * devices policy that excludes device nodes with major and minor of 0), but that's fine, in that
562 * case we use an AF_UNIX file node instead, which is not the same, but close enough for most
563 * uses. And most importantly, the kernel allows bind mounts from socket nodes to any non-directory
564 * file nodes, and that's the most important thing that matters.
565 *
566 * Note that the runtime directory argument shall be the top-level runtime directory, i.e. /run/ if
567 * we operate in system context and $XDG_RUNTIME_DIR if we operate in user context. */
568
e5f10caf 569 _cleanup_free_ char *d = NULL;
11e2be3a 570 const char *node;
e5f10caf 571
48b747fa
LP		 572 assert(ret);
573
574 if (!runtime_dir)
575 runtime_dir = "/run";
fe80fcc7 576
11e2be3a
LP		 577 if (S_ISLNK(mode))
578 return -EINVAL;
fe80fcc7 579
11e2be3a 580 node = inode_type_to_string(mode);
e5f10caf
AZ		 581 if (!node)
582 return -EINVAL;
583
11e2be3a 584 d = path_join(runtime_dir, "systemd/inaccessible", node);
48b747fa
LP		 585 if (!d)
586 return -ENOMEM;
587
cbed1dc8
LP		 588 /* On new kernels unprivileged users are permitted to create 0:0 char device nodes (because they also
589 * act as whiteout inode for overlayfs), but no other char or block device nodes. On old kernels no
590 * device node whatsoever may be created by unprivileged processes. Hence, if the caller asks for the
591 * inaccessible block device node let's see if the block device node actually exists, and if not,
592 * fall back to the character device node. From there fall back to the socket device node. This means
593 * in the best case we'll get the right device node type — but if not we'll hopefully at least get a
594 * device node at all. */
595
596 if (S_ISBLK(mode) &&
597 access(d, F_OK) < 0 && errno == ENOENT) {
598 free(d);
599 d = path_join(runtime_dir, "/systemd/inaccessible/chr");
600 if (!d)
601 return -ENOMEM;
602 }
603
604 if (IN_SET(mode & S_IFMT, S_IFBLK, S_IFCHR) &&
605 access(d, F_OK) < 0 && errno == ENOENT) {
48b747fa
LP		 606 free(d);
607 d = path_join(runtime_dir, "/systemd/inaccessible/sock");
608 if (!d)
609 return -ENOMEM;
610 }
e5f10caf 611
48b747fa 612 *ret = TAKE_PTR(d);
e5f10caf 613 return 0;
c4b41707 614}
60e76d48 615
da185cd0 616int mount_flags_to_string(unsigned long flags, char **ret) {
1c092b62 617 static const struct {
da185cd0 618 unsigned long flag;
1c092b62
YW		 619 const char *name;
620 } map[] = {
621 { .flag = MS_RDONLY, .name = "MS_RDONLY", },
622 { .flag = MS_NOSUID, .name = "MS_NOSUID", },
623 { .flag = MS_NODEV, .name = "MS_NODEV", },
624 { .flag = MS_NOEXEC, .name = "MS_NOEXEC", },
625 { .flag = MS_SYNCHRONOUS, .name = "MS_SYNCHRONOUS", },
626 { .flag = MS_REMOUNT, .name = "MS_REMOUNT", },
627 { .flag = MS_MANDLOCK, .name = "MS_MANDLOCK", },
628 { .flag = MS_DIRSYNC, .name = "MS_DIRSYNC", },
629 { .flag = MS_NOSYMFOLLOW, .name = "MS_NOSYMFOLLOW", },
630 { .flag = MS_NOATIME, .name = "MS_NOATIME", },
631 { .flag = MS_NODIRATIME, .name = "MS_NODIRATIME", },
632 { .flag = MS_BIND, .name = "MS_BIND", },
633 { .flag = MS_MOVE, .name = "MS_MOVE", },
634 { .flag = MS_REC, .name = "MS_REC", },
635 { .flag = MS_SILENT, .name = "MS_SILENT", },
636 { .flag = MS_POSIXACL, .name = "MS_POSIXACL", },
637 { .flag = MS_UNBINDABLE, .name = "MS_UNBINDABLE", },
638 { .flag = MS_PRIVATE, .name = "MS_PRIVATE", },
639 { .flag = MS_SLAVE, .name = "MS_SLAVE", },
640 { .flag = MS_SHARED, .name = "MS_SHARED", },
641 { .flag = MS_RELATIME, .name = "MS_RELATIME", },
642 { .flag = MS_KERNMOUNT, .name = "MS_KERNMOUNT", },
643 { .flag = MS_I_VERSION, .name = "MS_I_VERSION", },
644 { .flag = MS_STRICTATIME, .name = "MS_STRICTATIME", },
645 { .flag = MS_LAZYTIME, .name = "MS_LAZYTIME", },
646 };
647 _cleanup_free_ char *str = NULL;
648
4bee2333
YW		 649 assert(ret);
650
1c092b62
YW		 651 for (size_t i = 0; i < ELEMENTSOF(map); i++)
652 if (flags & map[i].flag) {
653 if (!strextend_with_separator(&str, "|", map[i].name))
654 return -ENOMEM;
655 flags &= ~map[i].flag;
656 }
657
658 if (!str || flags != 0)
659 if (strextendf_with_separator(&str, "|", "%lx", flags) < 0)
660 return -ENOMEM;
661
662 *ret = TAKE_PTR(str);
663 return 0;
60e76d48
ZJS		 664}
665
511a8cfe 666int mount_verbose_full(
60e76d48
ZJS		 667 int error_log_level,
668 const char *what,
669 const char *where,
670 const char *type,
671 unsigned long flags,
511a8cfe
LP		 672 const char *options,
673 bool follow_symlink) {
60e76d48 674
6ef8df2b
YW		 675 _cleanup_free_ char *fl = NULL, *o = NULL;
676 unsigned long f;
677 int r;
678
679 r = mount_option_mangle(options, flags, &f, &o);
680 if (r < 0)
681 return log_full_errno(error_log_level, r,
682 "Failed to mangle mount options %s: %m",
683 strempty(options));
60e76d48 684
1c092b62 685 (void) mount_flags_to_string(f, &fl);
60e76d48 686
f56f9c6b
LP		 687 if (FLAGS_SET(f, MS_REMOUNT|MS_BIND))
688 log_debug("Changing mount flags %s (%s \"%s\")...",
6ef8df2b 689 where, strnull(fl), strempty(o));
f56f9c6b
LP		 690 else if (f & MS_REMOUNT)
691 log_debug("Remounting superblock %s (%s \"%s\")...",
6ef8df2b 692 where, strnull(fl), strempty(o));
f56f9c6b
LP		 693 else if (f & (MS_SHARED|MS_PRIVATE|MS_SLAVE|MS_UNBINDABLE))
694 log_debug("Changing mount propagation %s (%s \"%s\")",
695 where, strnull(fl), strempty(o));
696 else if (f & MS_BIND)
60e76d48 697 log_debug("Bind-mounting %s on %s (%s \"%s\")...",
6ef8df2b
YW		 698 what, where, strnull(fl), strempty(o));
699 else if (f & MS_MOVE)
e2341b6b
DT		 700 log_debug("Moving mount %s %s %s (%s \"%s\")...",
701 what, special_glyph(SPECIAL_GLYPH_ARROW_RIGHT), where, strnull(fl), strempty(o));
60e76d48 702 else
3b493d94
LP		 703 log_debug("Mounting %s (%s) on %s (%s \"%s\")...",
704 strna(what), strna(type), where, strnull(fl), strempty(o));
511a8cfe
LP		 705
706 if (follow_symlink)
7c248223 707 r = RET_NERRNO(mount(what, where, type, f, o));
511a8cfe
LP		 708 else
709 r = mount_nofollow(what, where, type, f, o);
710 if (r < 0)
711 return log_full_errno(error_log_level, r,
3ccf6126
LP		 712 "Failed to mount %s (type %s) on %s (%s \"%s\"): %m",
713 strna(what), strna(type), where, strnull(fl), strempty(o));
60e76d48
ZJS		 714 return 0;
715}
716
30f5d104
LP		 717int umount_verbose(
718 int error_log_level,
719 const char *what,
720 int flags) {
721
722 assert(what);
723
60e76d48 724 log_debug("Umounting %s...", what);
30f5d104
LP		 725
726 if (umount2(what, flags) < 0)
727 return log_full_errno(error_log_level, errno,
728 "Failed to unmount %s: %m", what);
729
60e76d48
ZJS		 730 return 0;
731}
83555251 732
9e7f941a
YW		 733int mount_option_mangle(
734 const char *options,
735 unsigned long mount_flags,
736 unsigned long *ret_mount_flags,
737 char **ret_remaining_options) {
738
739 const struct libmnt_optmap *map;
740 _cleanup_free_ char *ret = NULL;
9e7f941a
YW		 741 int r;
742
3ca4ec20 743 /* This extracts mount flags from the mount options, and stores
9e7f941a
YW		 744 * non-mount-flag options to '*ret_remaining_options'.
745 * E.g.,
9f563f27 746 * "rw,nosuid,nodev,relatime,size=1630748k,mode=0700,uid=1000,gid=1000"
9e7f941a 747 * is split to MS_NOSUID|MS_NODEV|MS_RELATIME and
9f563f27 748 * "size=1630748k,mode=0700,uid=1000,gid=1000".
3ca4ec20 749 * See more examples in test-mount-util.c.
9e7f941a 750 *
3ca4ec20 751 * If 'options' does not contain any non-mount-flag options,
5238e957 752 * then '*ret_remaining_options' is set to NULL instead of empty string.
3ca4ec20
ZJS		 753 * The validity of options stored in '*ret_remaining_options' is not checked.
754 * If 'options' is NULL, this just copies 'mount_flags' to *ret_mount_flags. */
9e7f941a
YW		 755
756 assert(ret_mount_flags);
757 assert(ret_remaining_options);
758
759 map = mnt_get_builtin_optmap(MNT_LINUX_MAP);
760 if (!map)
761 return -EINVAL;
762
25086b4c 763 for (const char *p = options;;) {
9e7f941a
YW		 764 _cleanup_free_ char *word = NULL;
765 const struct libmnt_optmap *ent;
766
9b23679e 767 r = extract_first_word(&p, &word, ",", EXTRACT_KEEP_QUOTE);
9e7f941a
YW		 768 if (r < 0)
769 return r;
770 if (r == 0)
771 break;
772
773 for (ent = map; ent->name; ent++) {
774 /* All entries in MNT_LINUX_MAP do not take any argument.
775 * Thus, ent->name does not contain "=" or "[=]". */
776 if (!streq(word, ent->name))
777 continue;
778
779 if (!(ent->mask & MNT_INVERT))
780 mount_flags |= ent->id;
781 else if (mount_flags & ent->id)
782 mount_flags ^= ent->id;
783
784 break;
785 }
786
787 /* If 'word' is not a mount flag, then store it in '*ret_remaining_options'. */
ac6086fd
LB		 788 if (!ent->name &&
789 !startswith_no_case(word, "x-") &&
790 !strextend_with_separator(&ret, ",", word))
9e7f941a
YW		 791 return -ENOMEM;
792 }
793
794 *ret_mount_flags = mount_flags;
ae2a15bc 795 *ret_remaining_options = TAKE_PTR(ret);
9e7f941a
YW		 796
797 return 0;
798}
6af52c3a 799
a7e0199e
LB		 800static int mount_in_namespace_legacy(
801 const char *chased_src_path,
802 int chased_src_fd,
803 struct stat *chased_src_st,
6af52c3a
LB		 804 const char *propagate_path,
805 const char *incoming_path,
6af52c3a 806 const char *dest,
a7e0199e
LB		 807 int pidns_fd,
808 int mntns_fd,
809 int root_fd,
6af52c3a 810 bool read_only,
70599967
LB		 811 bool make_file_or_directory,
812 const MountOptions *options,
84be0c71 813 const ImagePolicy *image_policy,
70599967 814 bool is_image) {
6af52c3a 815
19ee48a6 816 _cleanup_close_pair_ int errno_pipe_fd[2] = PIPE_EBADF;
ddb6eeaf 817 char mount_slave[] = "/tmp/propagate.XXXXXX", *mount_tmp, *mount_outside, *p;
6af52c3a
LB		 818 bool mount_slave_created = false, mount_slave_mounted = false,
819 mount_tmp_created = false, mount_tmp_mounted = false,
820 mount_outside_created = false, mount_outside_mounted = false;
6af52c3a
LB		 821 pid_t child;
822 int r;
823
a7e0199e
LB		 824 assert(chased_src_path);
825 assert(chased_src_fd >= 0);
826 assert(chased_src_st);
6af52c3a
LB		 827 assert(propagate_path);
828 assert(incoming_path);
6af52c3a 829 assert(dest);
a7e0199e
LB		 830 assert(pidns_fd >= 0);
831 assert(mntns_fd >= 0);
832 assert(root_fd >= 0);
70599967 833 assert(!options || is_image);
6af52c3a 834
6af52c3a
LB		 835 p = strjoina(propagate_path, "/");
836 r = laccess(p, F_OK);
837 if (r < 0)
838 return log_debug_errno(r == -ENOENT ? SYNTHETIC_ERRNO(EOPNOTSUPP) : r, "Target does not allow propagation of mount points");
839
6af52c3a
LB		 840 /* Our goal is to install a new bind mount into the container,
841 possibly read-only. This is irritatingly complex
842 unfortunately, currently.
843
844 First, we start by creating a private playground in /tmp,
845 that we can mount MS_SLAVE. (Which is necessary, since
846 MS_MOVE cannot be applied to mounts with MS_SHARED parent
847 mounts.) */
848
849 if (!mkdtemp(mount_slave))
850 return log_debug_errno(errno, "Failed to create playground %s: %m", mount_slave);
851
852 mount_slave_created = true;
853
854 r = mount_nofollow_verbose(LOG_DEBUG, mount_slave, mount_slave, NULL, MS_BIND, NULL);
855 if (r < 0)
856 goto finish;
857
858 mount_slave_mounted = true;
859
860 r = mount_nofollow_verbose(LOG_DEBUG, NULL, mount_slave, NULL, MS_SLAVE, NULL);
861 if (r < 0)
862 goto finish;
863
864 /* Second, we mount the source file or directory to a directory inside of our MS_SLAVE playground. */
865 mount_tmp = strjoina(mount_slave, "/mount");
70599967
LB		 866 if (is_image)
867 r = mkdir_p(mount_tmp, 0700);
868 else
a7e0199e 869 r = make_mount_point_inode_from_stat(chased_src_st, mount_tmp, 0700);
6af52c3a
LB		 870 if (r < 0) {
871 log_debug_errno(r, "Failed to create temporary mount point %s: %m", mount_tmp);
872 goto finish;
873 }
874
875 mount_tmp_created = true;
876
70599967 877 if (is_image)
3e107272
LB		 878 r = verity_dissect_and_mount(
879 chased_src_fd,
880 chased_src_path,
881 mount_tmp,
882 options,
883 image_policy,
884 /* required_host_os_release_id= */ NULL,
885 /* required_host_os_release_version_id= */ NULL,
886 /* required_host_os_release_sysext_level= */ NULL,
887 /* required_sysext_scope= */ NULL,
888 /* ret_image= */ NULL);
70599967 889 else
ddb6eeaf 890 r = mount_follow_verbose(LOG_DEBUG, FORMAT_PROC_FD_PATH(chased_src_fd), mount_tmp, NULL, MS_BIND, NULL);
6af52c3a
LB		 891 if (r < 0)
892 goto finish;
893
894 mount_tmp_mounted = true;
895
896 /* Third, we remount the new bind mount read-only if requested. */
897 if (read_only) {
898 r = mount_nofollow_verbose(LOG_DEBUG, NULL, mount_tmp, NULL, MS_BIND|MS_REMOUNT|MS_RDONLY, NULL);
899 if (r < 0)
900 goto finish;
901 }
902
903 /* Fourth, we move the new bind mount into the propagation directory. This way it will appear there read-only
904 * right-away. */
905
906 mount_outside = strjoina(propagate_path, "/XXXXXX");
a7e0199e 907 if (is_image || S_ISDIR(chased_src_st->st_mode))
6af52c3a
LB		 908 r = mkdtemp(mount_outside) ? 0 : -errno;
909 else {
910 r = mkostemp_safe(mount_outside);
911 safe_close(r);
912 }
913 if (r < 0) {
914 log_debug_errno(r, "Cannot create propagation file or directory %s: %m", mount_outside);
915 goto finish;
916 }
917
918 mount_outside_created = true;
919
920 r = mount_nofollow_verbose(LOG_DEBUG, mount_tmp, mount_outside, NULL, MS_MOVE, NULL);
921 if (r < 0)
922 goto finish;
923
924 mount_outside_mounted = true;
925 mount_tmp_mounted = false;
926
a7e0199e 927 if (is_image || S_ISDIR(chased_src_st->st_mode))
6af52c3a
LB		 928 (void) rmdir(mount_tmp);
929 else
930 (void) unlink(mount_tmp);
931 mount_tmp_created = false;
932
933 (void) umount_verbose(LOG_DEBUG, mount_slave, UMOUNT_NOFOLLOW);
934 mount_slave_mounted = false;
935
936 (void) rmdir(mount_slave);
937 mount_slave_created = false;
938
939 if (pipe2(errno_pipe_fd, O_CLOEXEC|O_NONBLOCK) < 0) {
940 log_debug_errno(errno, "Failed to create pipe: %m");
941 goto finish;
942 }
943
2338a175 944 r = namespace_fork("(sd-bindmnt)", "(sd-bindmnt-inner)", NULL, 0, FORK_RESET_SIGNALS|FORK_DEATHSIG,
98f654fd 945 pidns_fd, mntns_fd, -1, -1, root_fd, &child);
6af52c3a
LB		 946 if (r < 0)
947 goto finish;
948 if (r == 0) {
03469b77 949 _cleanup_free_ char *mount_outside_fn = NULL, *mount_inside = NULL;
6af52c3a
LB		 950
951 errno_pipe_fd[0] = safe_close(errno_pipe_fd[0]);
952
6af52c3a 953 if (make_file_or_directory) {
70599967
LB		 954 if (!is_image) {
955 (void) mkdir_parents(dest, 0755);
a7e0199e 956 (void) make_mount_point_inode_from_stat(chased_src_st, dest, 0700);
70599967
LB		 957 } else
958 (void) mkdir_p(dest, 0755);
6af52c3a
LB		 959 }
960
961 /* Fifth, move the mount to the right place inside */
03469b77
LP		 962 r = path_extract_filename(mount_outside, &mount_outside_fn);
963 if (r < 0) {
964 log_debug_errno(r, "Failed to extract filename from propagation file or directory '%s': %m", mount_outside);
965 goto child_fail;
966 }
967
968 mount_inside = path_join(incoming_path, mount_outside_fn);
969 if (!mount_inside) {
970 r = log_oom_debug();
971 goto child_fail;
972 }
973
974 r = mount_nofollow_verbose(LOG_DEBUG, mount_inside, dest, NULL, MS_MOVE, NULL);
6af52c3a
LB		 975 if (r < 0)
976 goto child_fail;
977
978 _exit(EXIT_SUCCESS);
979
980 child_fail:
981 (void) write(errno_pipe_fd[1], &r, sizeof(r));
982 errno_pipe_fd[1] = safe_close(errno_pipe_fd[1]);
983
984 _exit(EXIT_FAILURE);
985 }
986
987 errno_pipe_fd[1] = safe_close(errno_pipe_fd[1]);
988
989 r = wait_for_terminate_and_check("(sd-bindmnt)", child, 0);
990 if (r < 0) {
991 log_debug_errno(r, "Failed to wait for child: %m");
992 goto finish;
993 }
994 if (r != EXIT_SUCCESS) {
995 if (read(errno_pipe_fd[0], &r, sizeof(r)) == sizeof(r))
996 log_debug_errno(r, "Failed to mount: %m");
997 else
998 log_debug("Child failed.");
999 goto finish;
1000 }
1001
1002finish:
1003 if (mount_outside_mounted)
1004 (void) umount_verbose(LOG_DEBUG, mount_outside, UMOUNT_NOFOLLOW);
1005 if (mount_outside_created) {
a7e0199e 1006 if (is_image || S_ISDIR(chased_src_st->st_mode))
6af52c3a
LB		 1007 (void) rmdir(mount_outside);
1008 else
1009 (void) unlink(mount_outside);
1010 }
1011
1012 if (mount_tmp_mounted)
1013 (void) umount_verbose(LOG_DEBUG, mount_tmp, UMOUNT_NOFOLLOW);
1014 if (mount_tmp_created) {
a7e0199e 1015 if (is_image || S_ISDIR(chased_src_st->st_mode))
6af52c3a
LB		 1016 (void) rmdir(mount_tmp);
1017 else
1018 (void) unlink(mount_tmp);
1019 }
1020
1021 if (mount_slave_mounted)
1022 (void) umount_verbose(LOG_DEBUG, mount_slave, UMOUNT_NOFOLLOW);
1023 if (mount_slave_created)
1024 (void) rmdir(mount_slave);
1025
1026 return r;
1027}
70599967 1028
a7e0199e
LB		 1029static int mount_in_namespace(
1030 pid_t target,
1031 const char *propagate_path,
1032 const char *incoming_path,
1033 const char *src,
1034 const char *dest,
1035 bool read_only,
1036 bool make_file_or_directory,
1037 const MountOptions *options,
1038 const ImagePolicy *image_policy,
1039 bool is_image) {
1040
ddba5a1a 1041 _cleanup_(dissected_image_unrefp) DissectedImage *img = NULL;
a7e0199e
LB		 1042 _cleanup_close_pair_ int errno_pipe_fd[2] = PIPE_EBADF;
1043 _cleanup_close_ int mntns_fd = -EBADF, root_fd = -EBADF, pidns_fd = -EBADF, chased_src_fd = -EBADF,
1044 new_mount_fd = -EBADF;
1045 _cleanup_free_ char *chased_src_path = NULL;
1046 struct stat st;
1047 pid_t child;
1048 int r;
1049
1050 assert(target > 0);
1051 assert(propagate_path);
1052 assert(incoming_path);
1053 assert(src);
1054 assert(dest);
1055 assert(!options || is_image);
1056
1057 r = namespace_open(target, &pidns_fd, &mntns_fd, NULL, NULL, &root_fd);
1058 if (r < 0)
1059 return log_debug_errno(r, "Failed to retrieve FDs of the target process' namespace: %m");
1060
1061 r = in_same_namespace(target, 0, NAMESPACE_MOUNT);
1062 if (r < 0)
1063 return log_debug_errno(r, "Failed to determine if mount namespaces are equal: %m");
1064 /* We can't add new mounts at runtime if the process wasn't started in a namespace */
1065 if (r > 0)
1066 return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to activate bind mount in target, not running in a mount namespace");
1067
1068 r = chase(src, NULL, 0, &chased_src_path, &chased_src_fd);
1069 if (r < 0)
1070 return log_debug_errno(r, "Failed to resolve source path of %s: %m", src);
1071 log_debug("Chased source path of %s to %s", src, chased_src_path);
1072
1073 if (fstat(chased_src_fd, &st) < 0)
1074 return log_debug_errno(errno, "Failed to stat() resolved source path %s: %m", src);
1075 if (S_ISLNK(st.st_mode)) /* This shouldn't really happen, given that we just chased the symlinks above, but let's better be safe… */
1076 return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP), "Source directory %s can't be a symbolic link", src);
1077
ddba5a1a 1078 if (!mount_new_api_supported()) /* Fallback if we can't use the new mount API */
a7e0199e
LB		 1079 return mount_in_namespace_legacy(
1080 chased_src_path,
1081 chased_src_fd,
1082 &st,
1083 propagate_path,
1084 incoming_path,
1085 dest,
1086 pidns_fd,
1087 mntns_fd,
1088 root_fd,
1089 read_only,
1090 make_file_or_directory,
1091 options,
1092 image_policy,
1093 is_image);
1094
ddba5a1a
LB		 1095 if (is_image) {
1096 r = verity_dissect_and_mount(
1097 chased_src_fd,
1098 chased_src_path,
1099 /* dest= */ NULL,
1100 options,
1101 image_policy,
1102 /* required_host_os_release_id= */ NULL,
1103 /* required_host_os_release_version_id= */ NULL,
1104 /* required_host_os_release_sysext_level= */ NULL,
1105 /* required_sysext_scope= */ NULL,
1106 &img);
1107 if (r < 0)
1108 return log_debug_errno(
1109 r,
1110 "Failed to dissect and mount image %s: %m",
1111 chased_src_path);
1112 } else {
1113 new_mount_fd = open_tree(
1114 chased_src_fd,
1115 "",
1116 OPEN_TREE_CLONE|OPEN_TREE_CLOEXEC|AT_SYMLINK_NOFOLLOW|AT_EMPTY_PATH);
1117 if (new_mount_fd < 0)
1118 return log_debug_errno(
1119 errno,
1120 "Failed to open mount point \"%s\": %m",
1121 chased_src_path);
1122
1123 if (read_only && mount_setattr(new_mount_fd, "", AT_EMPTY_PATH,
1124 &(struct mount_attr) {
1125 .attr_set = MOUNT_ATTR_RDONLY,
1126 }, MOUNT_ATTR_SIZE_VER0) < 0)
1127 return log_debug_errno(
1128 errno,
1129 "Failed to set mount flags for \"%s\": %m",
1130 chased_src_path);
1131 }
a7e0199e
LB		 1132
1133 if (pipe2(errno_pipe_fd, O_CLOEXEC|O_NONBLOCK) < 0)
1134 return log_debug_errno(errno, "Failed to create pipe: %m");
1135
1136 r = namespace_fork("(sd-bindmnt)",
1137 "(sd-bindmnt-inner)",
1138 /* except_fds= */ NULL,
1139 /* n_except_fds= */ 0,
1140 FORK_RESET_SIGNALS|FORK_DEATHSIG,
1141 pidns_fd,
1142 mntns_fd,
1143 /* netns_fd= */ -1,
1144 /* userns_fd= */ -1,
1145 root_fd,
1146 &child);
1147 if (r < 0)
1148 return log_debug_errno(r, "Failed to fork off: %m");
1149 if (r == 0) {
1150 errno_pipe_fd[0] = safe_close(errno_pipe_fd[0]);
1151
ddba5a1a 1152 if (make_file_or_directory)
a7e0199e 1153 (void) mkdir_parents(dest, 0755);
a7e0199e 1154
ddba5a1a
LB		 1155 if (img) {
1156 DissectImageFlags f = 0;
1157
1158 if (make_file_or_directory)
1159 f |= DISSECT_IMAGE_MKDIR;
1160
1161 if (read_only)
1162 f |= DISSECT_IMAGE_READ_ONLY;
1163
1164 r = dissected_image_mount(
1165 img,
1166 dest,
1167 /* uid_shift= */ UID_INVALID,
1168 /* uid_range= */ UID_INVALID,
1169 /* userns_fd= */ -EBADF,
1170 f);
1171 } else {
1172 if (make_file_or_directory)
1173 (void) make_mount_point_inode_from_stat(&st, dest, 0700);
1174
1175 r = RET_NERRNO(move_mount(new_mount_fd,
1176 "",
1177 -EBADF,
1178 dest,
1179 MOVE_MOUNT_F_EMPTY_PATH));
1180 }
1181 if (r < 0) {
1182 (void) write(errno_pipe_fd[1], &r, sizeof(r));
a7e0199e
LB		 1183 errno_pipe_fd[1] = safe_close(errno_pipe_fd[1]);
1184
1185 _exit(EXIT_FAILURE);
1186 }
1187
1188 _exit(EXIT_SUCCESS);
1189 }
1190
1191 errno_pipe_fd[1] = safe_close(errno_pipe_fd[1]);
1192
1193 r = wait_for_terminate_and_check("(sd-bindmnt)", child, 0);
1194 if (r < 0)
1195 return log_debug_errno(r, "Failed to wait for child: %m");
1196 if (r != EXIT_SUCCESS) {
1197 if (read(errno_pipe_fd[0], &r, sizeof(r)) == sizeof(r))
1198 return log_debug_errno(r, "Failed to mount: %m");
1199
1200 return log_debug_errno(SYNTHETIC_ERRNO(EPROTO), "Child failed.");
1201 }
1202
1203 return 0;
1204}
1205
70599967
LB		 1206int bind_mount_in_namespace(
1207 pid_t target,
1208 const char *propagate_path,
1209 const char *incoming_path,
1210 const char *src,
1211 const char *dest,
1212 bool read_only,
1213 bool make_file_or_directory) {
1214
84be0c71 1215 return mount_in_namespace(target, propagate_path, incoming_path, src, dest, read_only, make_file_or_directory, /* options= */ NULL, /* image_policy= */ NULL, /* is_image= */ false);
70599967
LB		 1216}
1217
1218int mount_image_in_namespace(
1219 pid_t target,
1220 const char *propagate_path,
1221 const char *incoming_path,
1222 const char *src,
1223 const char *dest,
1224 bool read_only,
1225 bool make_file_or_directory,
84be0c71
LP		 1226 const MountOptions *options,
1227 const ImagePolicy *image_policy) {
70599967 1228
84be0c71 1229 return mount_in_namespace(target, propagate_path, incoming_path, src, dest, read_only, make_file_or_directory, options, image_policy, /* is_image=*/ true);
70599967 1230}
14a25e1f
LP		 1231
1232int make_mount_point(const char *path) {
1233 int r;
1234
1235 assert(path);
1236
1237 /* If 'path' is already a mount point, does nothing and returns 0. If it is not it makes it one, and returns 1. */
1238
1239 r = path_is_mount_point(path, NULL, 0);
1240 if (r < 0)
1241 return log_debug_errno(r, "Failed to determine whether '%s' is a mount point: %m", path);
1242 if (r > 0)
1243 return 0;
1244
1245 r = mount_nofollow_verbose(LOG_DEBUG, path, path, NULL, MS_BIND|MS_REC, NULL);
1246 if (r < 0)
1247 return r;
1248
1249 return 1;
1250}
35fd3558 1251
f9ad896e
LP		 1252int fd_make_mount_point(int fd) {
1253 int r;
1254
1255 assert(fd >= 0);
1256
1257 r = fd_is_mount_point(fd, NULL, 0);
1258 if (r < 0)
1259 return log_debug_errno(r, "Failed to determine whether file descriptor is a mount point: %m");
1260 if (r > 0)
1261 return 0;
1262
1263 r = mount_follow_verbose(LOG_DEBUG, FORMAT_PROC_FD_PATH(fd), FORMAT_PROC_FD_PATH(fd), NULL, MS_BIND|MS_REC, NULL);
1264 if (r < 0)
1265 return r;
1266
1267 return 1;
1268}
1269
17b798d9 1270int make_userns(uid_t uid_shift, uid_t uid_range, uid_t owner, RemountIdmapping idmapping) {
254d1313 1271 _cleanup_close_ int userns_fd = -EBADF;
50ae2966 1272 _cleanup_free_ char *line = NULL;
35fd3558
LP		 1273
1274 /* Allocates a userns file descriptor with the mapping we need. For this we'll fork off a child
1275 * process whose only purpose is to give us a new user namespace. It's killed when we got it. */
1276
17b798d9
LP		 1277 if (!userns_shift_range_valid(uid_shift, uid_range))
1278 return -EINVAL;
1279
2b2777ed
QD		 1280 if (IN_SET(idmapping, REMOUNT_IDMAPPING_NONE, REMOUNT_IDMAPPING_HOST_ROOT)) {
1281 if (asprintf(&line, UID_FMT " " UID_FMT " " UID_FMT "\n", 0u, uid_shift, uid_range) < 0)
50ae2966 1282 return log_oom_debug();
35fd3558 1283
2b2777ed
QD		 1284 /* If requested we'll include an entry in the mapping so that the host root user can make
1285 * changes to the uidmapped mount like it normally would. Specifically, we'll map the user
1286 * with UID_MAPPED_ROOT on the backing fs to UID 0. This is useful, since nspawn code wants
1287 * to create various missing inodes in the OS tree before booting into it, and this becomes
1288 * very easy and straightforward to do if it can just do it under its own regular UID. Note
1289 * that in that case the container's runtime uidmap (i.e. the one the container payload
1290 * processes run in) will leave this UID unmapped, i.e. if we accidentally leave files owned
1291 * by host root in the already uidmapped tree around they'll show up as owned by 'nobody',
1292 * which is safe. (Of course, we shouldn't leave such inodes around, but always chown() them
1293 * to the container's own UID range, but it's good to have a safety net, in case we
1294 * forget it.) */
1295 if (idmapping == REMOUNT_IDMAPPING_HOST_ROOT)
1296 if (strextendf(&line,
1297 UID_FMT " " UID_FMT " " UID_FMT "\n",
1298 UID_MAPPED_ROOT, 0u, 1u) < 0)
1299 return log_oom_debug();
1300 }
1301
1302 if (idmapping == REMOUNT_IDMAPPING_HOST_OWNER) {
1303 /* Remap the owner of the bind mounted directory to the root user within the container. This
1304 * way every file written by root within the container to the bind-mounted directory will
1305 * be owned by the original user. All other user will remain unmapped. */
1306 if (asprintf(&line, UID_FMT " " UID_FMT " " UID_FMT "\n", owner, uid_shift, 1u) < 0)
1307 return log_oom_debug();
1308 }
1309
35fd3558 1310 /* We always assign the same UID and GID ranges */
979b0ff2
LP		 1311 userns_fd = userns_acquire(line, line);
1312 if (userns_fd < 0)
1313 return log_debug_errno(userns_fd, "Failed to acquire new userns: %m");
35fd3558
LP		 1314
1315 return TAKE_FD(userns_fd);
1316}
1317
17b798d9 1318int remount_idmap_fd(
35fd3558 1319 const char *p,
17b798d9 1320 int userns_fd) {
35fd3558 1321
17b798d9 1322 _cleanup_close_ int mount_fd = -EBADF;
35fd3558
LP		 1323 int r;
1324
1325 assert(p);
17b798d9 1326 assert(userns_fd >= 0);
35fd3558
LP		 1327
1328 /* Clone the mount point */
1329 mount_fd = open_tree(-1, p, OPEN_TREE_CLONE | OPEN_TREE_CLOEXEC);
1330 if (mount_fd < 0)
1331 return log_debug_errno(errno, "Failed to open tree of mounted filesystem '%s': %m", p);
1332
35fd3558
LP		 1333 /* Set the user namespace mapping attribute on the cloned mount point */
1334 if (mount_setattr(mount_fd, "", AT_EMPTY_PATH | AT_RECURSIVE,
1335 &(struct mount_attr) {
1336 .attr_set = MOUNT_ATTR_IDMAP,
1337 .userns_fd = userns_fd,
1338 }, sizeof(struct mount_attr)) < 0)
1339 return log_debug_errno(errno, "Failed to change bind mount attributes for '%s': %m", p);
1340
1341 /* Remove the old mount point */
1342 r = umount_verbose(LOG_DEBUG, p, UMOUNT_NOFOLLOW);
1343 if (r < 0)
1344 return r;
1345
1346 /* And place the cloned version in its place */
1347 if (move_mount(mount_fd, "", -1, p, MOVE_MOUNT_F_EMPTY_PATH) < 0)
1348 return log_debug_errno(errno, "Failed to attach UID mapped mount to '%s': %m", p);
1349
1350 return 0;
1351}
9c653536 1352
17b798d9
LP		 1353int remount_idmap(const char *p, uid_t uid_shift, uid_t uid_range, uid_t owner, RemountIdmapping idmapping) {
1354 _cleanup_close_ int userns_fd = -EBADF;
1355
1356 userns_fd = make_userns(uid_shift, uid_range, owner, idmapping);
1357 if (userns_fd < 0)
1358 return userns_fd;
1359
1360 return remount_idmap_fd(p, userns_fd);
1361}
1362
f63a2c48
YW		 1363typedef struct SubMount {
1364 char *path;
1365 int mount_fd;
1366} SubMount;
1367
1368static void sub_mount_clear(SubMount *s) {
1369 assert(s);
1370
1371 s->path = mfree(s->path);
1372 s->mount_fd = safe_close(s->mount_fd);
1373}
1374
1375static void sub_mount_array_free(SubMount *s, size_t n) {
1376 assert(s || n == 0);
1377
1378 for (size_t i = 0; i < n; i++)
1379 sub_mount_clear(s + i);
1380
1381 free(s);
1382}
1383
1384static int sub_mount_compare(const SubMount *a, const SubMount *b) {
1385 assert(a);
1386 assert(b);
1387 assert(a->path);
1388 assert(b->path);
1389
1390 return path_compare(a->path, b->path);
1391}
1392
1393static void sub_mount_drop(SubMount *s, size_t n) {
1394 assert(s || n == 0);
1395
1396 for (size_t m = 0, i = 1; i < n; i++) {
1397 if (path_startswith(s[i].path, s[m].path))
1398 sub_mount_clear(s + i);
1399 else
1400 m = i;
1401 }
1402}
1403
1b618bf1
LP		 1404static int get_sub_mounts(
1405 const char *prefix,
1b618bf1
LP		 1406 SubMount **ret_mounts,
1407 size_t *ret_n_mounts) {
f63a2c48
YW		 1408 _cleanup_(mnt_free_tablep) struct libmnt_table *table = NULL;
1409 _cleanup_(mnt_free_iterp) struct libmnt_iter *iter = NULL;
1410 SubMount *mounts = NULL;
1411 size_t n = 0;
1412 int r;
1413
1414 CLEANUP_ARRAY(mounts, n, sub_mount_array_free);
1415
1416 assert(prefix);
1417 assert(ret_mounts);
1418 assert(ret_n_mounts);
1419
1420 r = libmount_parse("/proc/self/mountinfo", NULL, &table, &iter);
1421 if (r < 0)
1422 return log_debug_errno(r, "Failed to parse /proc/self/mountinfo: %m");
1423
1424 for (;;) {
1425 _cleanup_close_ int mount_fd = -EBADF;
1426 _cleanup_free_ char *p = NULL;
1427 struct libmnt_fs *fs;
1428 const char *path;
1429 int id1, id2;
1430
1431 r = mnt_table_next_fs(table, iter, &fs);
1432 if (r == 1)
1433 break; /* EOF */
1434 if (r < 0)
1435 return log_debug_errno(r, "Failed to get next entry from /proc/self/mountinfo: %m");
1436
1437 path = mnt_fs_get_target(fs);
1438 if (!path)
1439 continue;
1440
1441 if (isempty(path_startswith(path, prefix)))
1442 continue;
1443
1444 id1 = mnt_fs_get_id(fs);
1445 r = path_get_mnt_id(path, &id2);
1446 if (r < 0) {
1447 log_debug_errno(r, "Failed to get mount ID of '%s', ignoring: %m", path);
1448 continue;
1449 }
1450 if (id1 != id2) {
1451 /* The path may be hidden by another over-mount or already remounted. */
1452 log_debug("The mount IDs of '%s' obtained by libmount and path_get_mnt_id() are different (%i vs %i), ignoring.",
1453 path, id1, id2);
1454 continue;
1455 }
1456
2b60ce54 1457 mount_fd = open(path, O_CLOEXEC|O_PATH);
f63a2c48
YW		 1458 if (mount_fd < 0) {
1459 if (errno == ENOENT) /* The path may be hidden by another over-mount or already unmounted. */
1460 continue;
1461
1b618bf1 1462 return log_debug_errno(errno, "Failed to open subtree of mounted filesystem '%s': %m", path);
f63a2c48
YW		 1463 }
1464
1465 p = strdup(path);
1466 if (!p)
1467 return log_oom_debug();
1468
1469 if (!GREEDY_REALLOC(mounts, n + 1))
1470 return log_oom_debug();
1471
1472 mounts[n++] = (SubMount) {
1473 .path = TAKE_PTR(p),
1474 .mount_fd = TAKE_FD(mount_fd),
1475 };
1476 }
1477
1478 typesafe_qsort(mounts, n, sub_mount_compare);
1479 sub_mount_drop(mounts, n);
1480
1481 *ret_mounts = TAKE_PTR(mounts);
1482 *ret_n_mounts = n;
1483 return 0;
1484}
1485
1b618bf1
LP		 1486int bind_mount_submounts(
1487 const char *source,
1488 const char *target) {
1489
1490 SubMount *mounts = NULL;
1491 size_t n = 0;
1492 int ret = 0, r;
1493
1494 /* Bind mounts all child mounts of 'source' to 'target'. Useful when setting up a new procfs instance
1495 * with new mount options to copy the original submounts over. */
1496
1497 assert(source);
1498 assert(target);
1499
1500 CLEANUP_ARRAY(mounts, n, sub_mount_array_free);
1501
2b60ce54 1502 r = get_sub_mounts(source, &mounts, &n);
1b618bf1
LP		 1503 if (r < 0)
1504 return r;
1505
1506 FOREACH_ARRAY(m, mounts, n) {
1507 _cleanup_free_ char *t = NULL;
1508 const char *suffix;
1509
1510 if (isempty(m->path))
1511 continue;
1512
1513 assert_se(suffix = path_startswith(m->path, source));
1514
1515 t = path_join(target, suffix);
1516 if (!t)
1517 return -ENOMEM;
1518
1519 r = path_is_mount_point(t, NULL, 0);
1520 if (r < 0) {
1521 log_debug_errno(r, "Failed to detect if '%s' already is a mount point, ignoring: %m", t);
1522 continue;
1523 }
1524 if (r > 0) {
1525 log_debug("Not bind mounting '%s' from '%s' to '%s', since there's already a mountpoint.", suffix, source, target);
1526 continue;
1527 }
1528
1529 r = mount_follow_verbose(LOG_DEBUG, FORMAT_PROC_FD_PATH(m->mount_fd), t, NULL, MS_BIND|MS_REC, NULL);
1530 if (r < 0 && ret == 0)
1531 ret = r;
1532 }
1533
1534 return ret;
1535}
1536
9c653536
ZJS		 1537int make_mount_point_inode_from_stat(const struct stat *st, const char *dest, mode_t mode) {
1538 assert(st);
1539 assert(dest);
1540
1541 if (S_ISDIR(st->st_mode))
1542 return mkdir_label(dest, mode);
1543 else
b6ca2b28 1544 return RET_NERRNO(mknod(dest, S_IFREG|(mode & ~0111), 0));
9c653536
ZJS		 1545}
1546
1547int make_mount_point_inode_from_path(const char *source, const char *dest, mode_t mode) {
1548 struct stat st;
1549
1550 assert(source);
1551 assert(dest);
1552
1553 if (stat(source, &st) < 0)
1554 return -errno;
1555
1556 return make_mount_point_inode_from_stat(&st, dest, mode);
1557}
506c1bb5
DDM		 1558
1559int trigger_automount_at(int dir_fd, const char *path) {
1560 _cleanup_free_ char *nested = NULL;
1561
1562 assert(dir_fd >= 0 || dir_fd == AT_FDCWD);
1563
1564 nested = path_join(path, "a");
1565 if (!nested)
1566 return -ENOMEM;
1567
1568 (void) faccessat(dir_fd, nested, F_OK, 0);
1569
1570 return 0;
1571}
1155f44f
LP		 1572
1573unsigned long credentials_fs_mount_flags(bool ro) {
1574 /* A tight set of mount flags for credentials mounts */
1575 return MS_NODEV|MS_NOEXEC|MS_NOSUID|ms_nosymfollow_supported()|(ro ? MS_RDONLY : 0);
1576}
1577
1578int mount_credentials_fs(const char *path, size_t size, bool ro) {
1579 _cleanup_free_ char *opts = NULL;
1580 int r, noswap_supported;
1581
1582 /* Mounts a file system we can place credentials in, i.e. with tight access modes right from the
1583 * beginning, and ideally swapping turned off. In order of preference:
1584 *
1585 * 1. tmpfs if it supports "noswap"
1586 * 2. ramfs
1587 * 3. tmpfs if it doesn't support "noswap"
1588 */
1589
1590 noswap_supported = mount_option_supported("tmpfs", "noswap", NULL); /* Check explicitly to avoid kmsg noise */
1591 if (noswap_supported > 0) {
1592 _cleanup_free_ char *noswap_opts = NULL;
1593
1594 if (asprintf(&noswap_opts, "mode=0700,nr_inodes=1024,size=%zu,noswap", size) < 0)
1595 return -ENOMEM;
1596
1597 /* Best case: tmpfs with noswap (needs kernel >= 6.3) */
1598
1599 r = mount_nofollow_verbose(
1600 LOG_DEBUG,
1601 "tmpfs",
1602 path,
1603 "tmpfs",
1604 credentials_fs_mount_flags(ro),
1605 noswap_opts);
1606 if (r >= 0)
1607 return r;
1608 }
1609
1610 r = mount_nofollow_verbose(
1611 LOG_DEBUG,
1612 "ramfs",
1613 path,
1614 "ramfs",
1615 credentials_fs_mount_flags(ro),
1616 "mode=0700");
1617 if (r >= 0)
1618 return r;
1619
1620 if (asprintf(&opts, "mode=0700,nr_inodes=1024,size=%zu", size) < 0)
1621 return -ENOMEM;
1622
1623 return mount_nofollow_verbose(
1624 LOG_DEBUG,
1625 "tmpfs",
1626 path,
1627 "tmpfs",
1628 credentials_fs_mount_flags(ro),
1629 opts);
1630}
44cc82bf
LP		 1631
1632int make_fsmount(
1633 int error_log_level,
1634 const char *what,
1635 const char *type,
1636 unsigned long flags,
1637 const char *options,
1638 int userns_fd) {
1639
1640 _cleanup_close_ int fs_fd = -EBADF, mnt_fd = -EBADF;
1641 _cleanup_free_ char *o = NULL;
1642 unsigned long f;
1643 int r;
1644
1645 assert(type);
1646 assert(what);
1647
1648 r = mount_option_mangle(options, flags, &f, &o);
1649 if (r < 0)
1650 return log_full_errno(
1651 error_log_level, r, "Failed to mangle mount options %s: %m",
1652 strempty(options));
1653
1654 if (DEBUG_LOGGING) {
1655 _cleanup_free_ char *fl = NULL;
1656 (void) mount_flags_to_string(f, &fl);
1657
1658 log_debug("Creating mount fd for %s (%s) (%s \"%s\")...",
1659 strna(what), strna(type), strnull(fl), strempty(o));
1660 }
1661
1662 fs_fd = fsopen(type, FSOPEN_CLOEXEC);
1663 if (fs_fd < 0)
1664 return log_full_errno(error_log_level, errno, "Failed to open superblock for \"%s\": %m", type);
1665
1666 if (fsconfig(fs_fd, FSCONFIG_SET_STRING, "source", what, 0) < 0)
1667 return log_full_errno(error_log_level, errno, "Failed to set mount source for \"%s\" to \"%s\": %m", type, what);
1668
1669 if (FLAGS_SET(f, MS_RDONLY))
1670 if (fsconfig(fs_fd, FSCONFIG_SET_FLAG, "ro", NULL, 0) < 0)
1671 return log_full_errno(error_log_level, errno, "Failed to set read only mount flag for \"%s\": %m", type);
1672
1673 for (const char *p = o;;) {
1674 _cleanup_free_ char *word = NULL;
1675 char *eq;
1676
1677 r = extract_first_word(&p, &word, ",", EXTRACT_KEEP_QUOTE);
1678 if (r < 0)
1679 return log_full_errno(error_log_level, r, "Failed to parse mount option string \"%s\": %m", o);
1680 if (r == 0)
1681 break;
1682
1683 eq = strchr(word, '=');
1684 if (eq) {
1685 *eq = 0;
1686 eq++;
1687
1688 if (fsconfig(fs_fd, FSCONFIG_SET_STRING, word, eq, 0) < 0)
1689 return log_full_errno(error_log_level, errno, "Failed to set mount option \"%s=%s\" for \"%s\": %m", word, eq, type);
1690 } else {
1691 if (fsconfig(fs_fd, FSCONFIG_SET_FLAG, word, NULL, 0) < 0)
1692 return log_full_errno(error_log_level, errno, "Failed to set mount flag \"%s\" for \"%s\": %m", word, type);
1693 }
1694 }
1695
1696 if (fsconfig(fs_fd, FSCONFIG_CMD_CREATE, NULL, NULL, 0) < 0)
1697 return log_full_errno(error_log_level, errno, "Failed to realize fs fd for \"%s\" (\"%s\"): %m", what, type);
1698
1699 mnt_fd = fsmount(fs_fd, FSMOUNT_CLOEXEC, 0);
1700 if (mnt_fd < 0)
1701 return log_full_errno(error_log_level, errno, "Failed to create mount fd for \"%s\" (\"%s\"): %m", what, type);
1702
1703 if (mount_setattr(mnt_fd, "", AT_EMPTY_PATH|AT_RECURSIVE,
1704 &(struct mount_attr) {
1705 .attr_set = ms_flags_to_mount_attr(f) | (userns_fd >= 0 ? MOUNT_ATTR_IDMAP : 0),
1706 .userns_fd = userns_fd,
1707 }, MOUNT_ATTR_SIZE_VER0) < 0)
1708 return log_full_errno(error_log_level,
1709 errno,
1710 "Failed to set mount flags for \"%s\" (\"%s\"): %m",
1711 what,
1712 type);
1713
1714 return TAKE_FD(mnt_fd);
1715}
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