1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3 #include <errno.h>
4 #include <signal.h>
5 #include <stdio.h>
6 #include <sys/epoll.h>
7
8 #include "sd-messages.h"
9
10 #include "alloc-util.h"
11 #include "dbus-mount.h"
12 #include "dbus-unit.h"
13 #include "device.h"
14 #include "exit-status.h"
15 #include "format-util.h"
16 #include "fstab-util.h"
17 #include "libmount-util.h"
18 #include "log.h"
19 #include "manager.h"
20 #include "mkdir-label.h"
21 #include "mount-setup.h"
22 #include "mount.h"
23 #include "mountpoint-util.h"
24 #include "parse-util.h"
25 #include "path-util.h"
26 #include "process-util.h"
27 #include "serialize.h"
28 #include "special.h"
29 #include "string-table.h"
30 #include "string-util.h"
31 #include "strv.h"
32 #include "unit-name.h"
33 #include "unit.h"
34
35 #define RETRY_UMOUNT_MAX 32
36
37 static const UnitActiveState state_translation_table[_MOUNT_STATE_MAX] = {
38 [MOUNT_DEAD] = UNIT_INACTIVE,
39 [MOUNT_MOUNTING] = UNIT_ACTIVATING,
40 [MOUNT_MOUNTING_DONE] = UNIT_ACTIVATING,
41 [MOUNT_MOUNTED] = UNIT_ACTIVE,
42 [MOUNT_REMOUNTING] = UNIT_RELOADING,
43 [MOUNT_UNMOUNTING] = UNIT_DEACTIVATING,
44 [MOUNT_REMOUNTING_SIGTERM] = UNIT_RELOADING,
45 [MOUNT_REMOUNTING_SIGKILL] = UNIT_RELOADING,
46 [MOUNT_UNMOUNTING_SIGTERM] = UNIT_DEACTIVATING,
47 [MOUNT_UNMOUNTING_SIGKILL] = UNIT_DEACTIVATING,
48 [MOUNT_FAILED] = UNIT_FAILED,
49 [MOUNT_CLEANING] = UNIT_MAINTENANCE,
50 };
51
52 static int mount_dispatch_timer(sd_event_source *source, usec_t usec, void *userdata);
53 static int mount_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata);
54 static int mount_process_proc_self_mountinfo(Manager *m);
55
MOUNT_STATE_WITH_PROCESS(MountState state)56 static bool MOUNT_STATE_WITH_PROCESS(MountState state) {
57 return IN_SET(state,
58 MOUNT_MOUNTING,
59 MOUNT_MOUNTING_DONE,
60 MOUNT_REMOUNTING,
61 MOUNT_REMOUNTING_SIGTERM,
62 MOUNT_REMOUNTING_SIGKILL,
63 MOUNT_UNMOUNTING,
64 MOUNT_UNMOUNTING_SIGTERM,
65 MOUNT_UNMOUNTING_SIGKILL,
66 MOUNT_CLEANING);
67 }
68
get_mount_parameters_fragment(Mount * m)69 static MountParameters* get_mount_parameters_fragment(Mount *m) {
70 assert(m);
71
72 if (m->from_fragment)
73 return &m->parameters_fragment;
74
75 return NULL;
76 }
77
get_mount_parameters(Mount * m)78 static MountParameters* get_mount_parameters(Mount *m) {
79 assert(m);
80
81 if (m->from_proc_self_mountinfo)
82 return &m->parameters_proc_self_mountinfo;
83
84 return get_mount_parameters_fragment(m);
85 }
86
mount_is_network(const MountParameters * p)87 static bool mount_is_network(const MountParameters *p) {
88 assert(p);
89
90 if (fstab_test_option(p->options, "_netdev\0"))
91 return true;
92
93 if (p->fstype && fstype_is_network(p->fstype))
94 return true;
95
96 return false;
97 }
98
mount_is_nofail(const Mount * m)99 static bool mount_is_nofail(const Mount *m) {
100 assert(m);
101
102 if (!m->from_fragment)
103 return false;
104
105 return fstab_test_yes_no_option(m->parameters_fragment.options, "nofail\0" "fail\0");
106 }
107
mount_is_loop(const MountParameters * p)108 static bool mount_is_loop(const MountParameters *p) {
109 assert(p);
110
111 if (fstab_test_option(p->options, "loop\0"))
112 return true;
113
114 return false;
115 }
116
mount_is_bind(const MountParameters * p)117 static bool mount_is_bind(const MountParameters *p) {
118 assert(p);
119
120 if (fstab_test_option(p->options, "bind\0" "rbind\0"))
121 return true;
122
123 if (p->fstype && STR_IN_SET(p->fstype, "bind", "rbind"))
124 return true;
125
126 return false;
127 }
128
mount_is_bound_to_device(Mount * m)129 static bool mount_is_bound_to_device(Mount *m) {
130 const MountParameters *p;
131
132 assert(m);
133
134 /* Determines whether to place a Requires= or BindsTo= dependency on the backing device unit. We do
135 * this by checking for the x-systemd.device-bound mount option. Iff it is set we use BindsTo=,
136 * otherwise Requires=. But note that we might combine the latter with StopPropagatedFrom=, see
137 * below. */
138
139 p = get_mount_parameters(m);
140 if (!p)
141 return false;
142
143 return fstab_test_option(p->options, "x-systemd.device-bound\0");
144 }
145
mount_propagate_stop(Mount * m)146 static bool mount_propagate_stop(Mount *m) {
147 assert(m);
148
149 if (mount_is_bound_to_device(m)) /* If we are using BindsTo= the stop propagation is implicit, no need to bother */
150 return false;
151
152 return m->from_fragment; /* let's propagate stop whenever this is an explicitly configured unit,
153 * otherwise let's not bother. */
154 }
155
mount_needs_quota(const MountParameters * p)156 static bool mount_needs_quota(const MountParameters *p) {
157 assert(p);
158
159 /* Quotas are not enabled on network filesystems, but we want them, for example, on storage connected via
160 * iscsi. We hence don't use mount_is_network() here, as that would also return true for _netdev devices. */
161 if (p->fstype && fstype_is_network(p->fstype))
162 return false;
163
164 if (mount_is_bind(p))
165 return false;
166
167 return fstab_test_option(p->options,
168 "usrquota\0" "grpquota\0" "quota\0" "usrjquota\0" "grpjquota\0");
169 }
170
mount_init(Unit * u)171 static void mount_init(Unit *u) {
172 Mount *m = MOUNT(u);
173
174 assert(m);
175 assert(u);
176 assert(u->load_state == UNIT_STUB);
177
178 m->timeout_usec = u->manager->default_timeout_start_usec;
179
180 m->exec_context.std_output = u->manager->default_std_output;
181 m->exec_context.std_error = u->manager->default_std_error;
182
183 m->directory_mode = 0755;
184
185 /* We need to make sure that /usr/bin/mount is always called
186 * in the same process group as us, so that the autofs kernel
187 * side doesn't send us another mount request while we are
188 * already trying to comply its last one. */
189 m->exec_context.same_pgrp = true;
190
191 m->control_command_id = _MOUNT_EXEC_COMMAND_INVALID;
192
193 u->ignore_on_isolate = true;
194 }
195
mount_arm_timer(Mount * m,usec_t usec)196 static int mount_arm_timer(Mount *m, usec_t usec) {
197 int r;
198
199 assert(m);
200
201 if (m->timer_event_source) {
202 r = sd_event_source_set_time(m->timer_event_source, usec);
203 if (r < 0)
204 return r;
205
206 return sd_event_source_set_enabled(m->timer_event_source, SD_EVENT_ONESHOT);
207 }
208
209 if (usec == USEC_INFINITY)
210 return 0;
211
212 r = sd_event_add_time(
213 UNIT(m)->manager->event,
214 &m->timer_event_source,
215 CLOCK_MONOTONIC,
216 usec, 0,
217 mount_dispatch_timer, m);
218 if (r < 0)
219 return r;
220
221 (void) sd_event_source_set_description(m->timer_event_source, "mount-timer");
222
223 return 0;
224 }
225
mount_unwatch_control_pid(Mount * m)226 static void mount_unwatch_control_pid(Mount *m) {
227 assert(m);
228
229 if (m->control_pid <= 0)
230 return;
231
232 unit_unwatch_pid(UNIT(m), TAKE_PID(m->control_pid));
233 }
234
mount_parameters_done(MountParameters * p)235 static void mount_parameters_done(MountParameters *p) {
236 assert(p);
237
238 p->what = mfree(p->what);
239 p->options = mfree(p->options);
240 p->fstype = mfree(p->fstype);
241 }
242
mount_done(Unit * u)243 static void mount_done(Unit *u) {
244 Mount *m = MOUNT(u);
245
246 assert(m);
247
248 m->where = mfree(m->where);
249
250 mount_parameters_done(&m->parameters_proc_self_mountinfo);
251 mount_parameters_done(&m->parameters_fragment);
252
253 m->exec_runtime = exec_runtime_unref(m->exec_runtime, false);
254 exec_command_done_array(m->exec_command, _MOUNT_EXEC_COMMAND_MAX);
255 m->control_command = NULL;
256
257 dynamic_creds_unref(&m->dynamic_creds);
258
259 mount_unwatch_control_pid(m);
260
261 m->timer_event_source = sd_event_source_disable_unref(m->timer_event_source);
262 }
263
update_parameters_proc_self_mountinfo(Mount * m,const char * what,const char * options,const char * fstype)264 static int update_parameters_proc_self_mountinfo(
265 Mount *m,
266 const char *what,
267 const char *options,
268 const char *fstype) {
269
270 MountParameters *p;
271 int r, q, w;
272
273 p = &m->parameters_proc_self_mountinfo;
274
275 r = free_and_strdup(&p->what, what);
276 if (r < 0)
277 return r;
278
279 q = free_and_strdup(&p->options, options);
280 if (q < 0)
281 return q;
282
283 w = free_and_strdup(&p->fstype, fstype);
284 if (w < 0)
285 return w;
286
287 return r > 0 || q > 0 || w > 0;
288 }
289
mount_add_mount_dependencies(Mount * m)290 static int mount_add_mount_dependencies(Mount *m) {
291 MountParameters *pm;
292 Unit *other;
293 Set *s;
294 int r;
295
296 assert(m);
297
298 if (!path_equal(m->where, "/")) {
299 _cleanup_free_ char *parent = NULL;
300
301 /* Adds in links to other mount points that might lie further up in the hierarchy */
302
303 parent = dirname_malloc(m->where);
304 if (!parent)
305 return -ENOMEM;
306
307 r = unit_require_mounts_for(UNIT(m), parent, UNIT_DEPENDENCY_IMPLICIT);
308 if (r < 0)
309 return r;
310 }
311
312 /* Adds in dependencies to other mount points that might be needed for the source path (if this is a bind mount
313 * or a loop mount) to be available. */
314 pm = get_mount_parameters_fragment(m);
315 if (pm && pm->what &&
316 path_is_absolute(pm->what) &&
317 (mount_is_bind(pm) || mount_is_loop(pm) || !mount_is_network(pm))) {
318
319 r = unit_require_mounts_for(UNIT(m), pm->what, UNIT_DEPENDENCY_FILE);
320 if (r < 0)
321 return r;
322 }
323
324 /* Adds in dependencies to other units that use this path or paths further down in the hierarchy */
325 s = manager_get_units_requiring_mounts_for(UNIT(m)->manager, m->where);
326 SET_FOREACH(other, s) {
327
328 if (other->load_state != UNIT_LOADED)
329 continue;
330
331 if (other == UNIT(m))
332 continue;
333
334 r = unit_add_dependency(other, UNIT_AFTER, UNIT(m), true, UNIT_DEPENDENCY_PATH);
335 if (r < 0)
336 return r;
337
338 if (UNIT(m)->fragment_path) {
339 /* If we have fragment configuration, then make this dependency required */
340 r = unit_add_dependency(other, UNIT_REQUIRES, UNIT(m), true, UNIT_DEPENDENCY_PATH);
341 if (r < 0)
342 return r;
343 }
344 }
345
346 return 0;
347 }
348
mount_add_device_dependencies(Mount * m)349 static int mount_add_device_dependencies(Mount *m) {
350 UnitDependencyMask mask;
351 MountParameters *p;
352 UnitDependency dep;
353 int r;
354
355 assert(m);
356
357 p = get_mount_parameters(m);
358 if (!p)
359 return 0;
360
361 if (!p->what)
362 return 0;
363
364 if (mount_is_bind(p))
365 return 0;
366
367 if (!is_device_path(p->what))
368 return 0;
369
370 /* /dev/root is a really weird thing, it's not a real device, but just a path the kernel exports for
371 * the root file system specified on the kernel command line. Ignore it here. */
372 if (PATH_IN_SET(p->what, "/dev/root", "/dev/nfs"))
373 return 0;
374
375 if (path_equal(m->where, "/"))
376 return 0;
377
378 /* Mount units from /proc/self/mountinfo are not bound to devices by default since they're subject to
379 * races when mounts are established by other tools with different backing devices than what we
380 * maintain. The user can still force this to be a BindsTo= dependency with an appropriate option (or
381 * udev property) so the mount units are automatically stopped when the device disappears
382 * suddenly. */
383 dep = mount_is_bound_to_device(m) ? UNIT_BINDS_TO : UNIT_REQUIRES;
384
385 /* We always use 'what' from /proc/self/mountinfo if mounted */
386 mask = m->from_proc_self_mountinfo ? UNIT_DEPENDENCY_MOUNTINFO_IMPLICIT : UNIT_DEPENDENCY_FILE;
387
388 r = unit_add_node_dependency(UNIT(m), p->what, dep, mask);
389 if (r < 0)
390 return r;
391 if (mount_propagate_stop(m)) {
392 r = unit_add_node_dependency(UNIT(m), p->what, UNIT_STOP_PROPAGATED_FROM, mask);
393 if (r < 0)
394 return r;
395 }
396
397 return unit_add_blockdev_dependency(UNIT(m), p->what, mask);
398 }
399
mount_add_quota_dependencies(Mount * m)400 static int mount_add_quota_dependencies(Mount *m) {
401 UnitDependencyMask mask;
402 MountParameters *p;
403 int r;
404
405 assert(m);
406
407 if (!MANAGER_IS_SYSTEM(UNIT(m)->manager))
408 return 0;
409
410 p = get_mount_parameters_fragment(m);
411 if (!p)
412 return 0;
413
414 if (!mount_needs_quota(p))
415 return 0;
416
417 mask = m->from_fragment ? UNIT_DEPENDENCY_FILE : UNIT_DEPENDENCY_MOUNTINFO_IMPLICIT;
418
419 r = unit_add_two_dependencies_by_name(UNIT(m), UNIT_BEFORE, UNIT_WANTS, SPECIAL_QUOTACHECK_SERVICE, true, mask);
420 if (r < 0)
421 return r;
422
423 r = unit_add_two_dependencies_by_name(UNIT(m), UNIT_BEFORE, UNIT_WANTS, SPECIAL_QUOTAON_SERVICE, true, mask);
424 if (r < 0)
425 return r;
426
427 return 0;
428 }
429
mount_is_extrinsic(Unit * u)430 static bool mount_is_extrinsic(Unit *u) {
431 MountParameters *p;
432 Mount *m = MOUNT(u);
433 assert(m);
434
435 /* Returns true for all units that are "magic" and should be excluded from the usual
436 * start-up and shutdown dependencies. We call them "extrinsic" here, as they are generally
437 * mounted outside of the systemd dependency logic. We shouldn't attempt to manage them
438 * ourselves but it's fine if the user operates on them with us. */
439
440 /* We only automatically manage mounts if we are in system mode */
441 if (MANAGER_IS_USER(u->manager))
442 return true;
443
444 p = get_mount_parameters(m);
445 if (p && fstab_is_extrinsic(m->where, p->options))
446 return true;
447
448 return false;
449 }
450
mount_add_default_ordering_dependencies(Mount * m,MountParameters * p,UnitDependencyMask mask)451 static int mount_add_default_ordering_dependencies(
452 Mount *m,
453 MountParameters *p,
454 UnitDependencyMask mask) {
455
456 const char *after, *before, *e;
457 int r;
458
459 assert(m);
460
461 e = path_startswith(m->where, "/sysroot");
462 if (e && in_initrd()) {
463 /* All mounts under /sysroot need to happen later, at initrd-fs.target time. IOW,
464 * it's not technically part of the basic initrd filesystem itself, and so
465 * shouldn't inherit the default Before=local-fs.target dependency. */
466
467 after = NULL;
468 before = isempty(e) ? SPECIAL_INITRD_ROOT_FS_TARGET : SPECIAL_INITRD_FS_TARGET;
469
470 } else if (mount_is_network(p)) {
471 after = SPECIAL_REMOTE_FS_PRE_TARGET;
472 before = SPECIAL_REMOTE_FS_TARGET;
473
474 } else {
475 after = SPECIAL_LOCAL_FS_PRE_TARGET;
476 before = SPECIAL_LOCAL_FS_TARGET;
477 }
478
479 if (!mount_is_nofail(m)) {
480 r = unit_add_dependency_by_name(UNIT(m), UNIT_BEFORE, before, true, mask);
481 if (r < 0)
482 return r;
483 }
484
485 if (after) {
486 r = unit_add_dependency_by_name(UNIT(m), UNIT_AFTER, after, true, mask);
487 if (r < 0)
488 return r;
489 }
490
491 return unit_add_two_dependencies_by_name(UNIT(m), UNIT_BEFORE, UNIT_CONFLICTS,
492 SPECIAL_UMOUNT_TARGET, true, mask);
493 }
494
mount_add_default_dependencies(Mount * m)495 static int mount_add_default_dependencies(Mount *m) {
496 UnitDependencyMask mask;
497 MountParameters *p;
498 int r;
499
500 assert(m);
501
502 if (!UNIT(m)->default_dependencies)
503 return 0;
504
505 /* We do not add any default dependencies to /, /usr or /run/initramfs/, since they are
506 * guaranteed to stay mounted the whole time, since our system is on it. Also, don't
507 * bother with anything mounted below virtual file systems, it's also going to be virtual,
508 * and hence not worth the effort. */
509 if (mount_is_extrinsic(UNIT(m)))
510 return 0;
511
512 p = get_mount_parameters(m);
513 if (!p)
514 return 0;
515
516 mask = m->from_fragment ? UNIT_DEPENDENCY_FILE : UNIT_DEPENDENCY_MOUNTINFO_DEFAULT;
517
518 r = mount_add_default_ordering_dependencies(m, p, mask);
519 if (r < 0)
520 return r;
521
522 if (mount_is_network(p)) {
523 /* We order ourselves after network.target. This is primarily useful at shutdown:
524 * services that take down the network should order themselves before
525 * network.target, so that they are shut down only after this mount unit is
526 * stopped. */
527
528 r = unit_add_dependency_by_name(UNIT(m), UNIT_AFTER, SPECIAL_NETWORK_TARGET, true, mask);
529 if (r < 0)
530 return r;
531
532 /* We pull in network-online.target, and order ourselves after it. This is useful
533 * at start-up to actively pull in tools that want to be started before we start
534 * mounting network file systems, and whose purpose it is to delay this until the
535 * network is "up". */
536
537 r = unit_add_two_dependencies_by_name(UNIT(m), UNIT_WANTS, UNIT_AFTER, SPECIAL_NETWORK_ONLINE_TARGET, true, mask);
538 if (r < 0)
539 return r;
540 }
541
542 /* If this is a tmpfs mount then we have to unmount it before we try to deactivate swaps */
543 if (streq_ptr(p->fstype, "tmpfs")) {
544 r = unit_add_dependency_by_name(UNIT(m), UNIT_AFTER, SPECIAL_SWAP_TARGET, true, mask);
545 if (r < 0)
546 return r;
547 }
548
549 return 0;
550 }
551
mount_verify(Mount * m)552 static int mount_verify(Mount *m) {
553 _cleanup_free_ char *e = NULL;
554 MountParameters *p;
555 int r;
556
557 assert(m);
558 assert(UNIT(m)->load_state == UNIT_LOADED);
559
560 if (!m->from_fragment && !m->from_proc_self_mountinfo && !UNIT(m)->perpetual)
561 return -ENOENT;
562
563 r = unit_name_from_path(m->where, ".mount", &e);
564 if (r < 0)
565 return log_unit_error_errno(UNIT(m), r, "Failed to generate unit name from mount path: %m");
566
567 if (!unit_has_name(UNIT(m), e))
568 return log_unit_error_errno(UNIT(m), SYNTHETIC_ERRNO(ENOEXEC), "Where= setting doesn't match unit name. Refusing.");
569
570 if (mount_point_is_api(m->where) || mount_point_ignore(m->where))
571 return log_unit_error_errno(UNIT(m), SYNTHETIC_ERRNO(ENOEXEC), "Cannot create mount unit for API file system %s. Refusing.", m->where);
572
573 p = get_mount_parameters_fragment(m);
574 if (p && !p->what && !UNIT(m)->perpetual)
575 return log_unit_error_errno(UNIT(m), SYNTHETIC_ERRNO(ENOEXEC),
576 "What= setting is missing. Refusing.");
577
578 if (m->exec_context.pam_name && m->kill_context.kill_mode != KILL_CONTROL_GROUP)
579 return log_unit_error_errno(UNIT(m), SYNTHETIC_ERRNO(ENOEXEC), "Unit has PAM enabled. Kill mode must be set to control-group'. Refusing.");
580
581 return 0;
582 }
583
mount_add_non_exec_dependencies(Mount * m)584 static int mount_add_non_exec_dependencies(Mount *m) {
585 int r;
586 assert(m);
587
588 /* Adds in all dependencies directly responsible for ordering the mount, as opposed to dependencies
589 * resulting from the ExecContext and such. */
590
591 r = mount_add_device_dependencies(m);
592 if (r < 0)
593 return r;
594
595 r = mount_add_mount_dependencies(m);
596 if (r < 0)
597 return r;
598
599 r = mount_add_quota_dependencies(m);
600 if (r < 0)
601 return r;
602
603 r = mount_add_default_dependencies(m);
604 if (r < 0)
605 return r;
606
607 return 0;
608 }
609
mount_add_extras(Mount * m)610 static int mount_add_extras(Mount *m) {
611 Unit *u = UNIT(m);
612 int r;
613
614 assert(m);
615
616 /* Note: this call might be called after we already have been loaded once (and even when it has already been
617 * activated), in case data from /proc/self/mountinfo has changed. This means all code here needs to be ready
618 * to run with an already set up unit. */
619
620 if (u->fragment_path)
621 m->from_fragment = true;
622
623 if (!m->where) {
624 r = unit_name_to_path(u->id, &m->where);
625 if (r == -ENAMETOOLONG)
626 log_unit_error_errno(u, r, "Failed to derive mount point path from unit name, because unit name is hashed. "
627 "Set \"Where=\" in the unit file explicitly.");
628 if (r < 0)
629 return r;
630 }
631
632 path_simplify(m->where);
633
634 if (!u->description) {
635 r = unit_set_description(u, m->where);
636 if (r < 0)
637 return r;
638 }
639
640 r = unit_patch_contexts(u);
641 if (r < 0)
642 return r;
643
644 r = unit_add_exec_dependencies(u, &m->exec_context);
645 if (r < 0)
646 return r;
647
648 r = unit_set_default_slice(u);
649 if (r < 0)
650 return r;
651
652 r = mount_add_non_exec_dependencies(m);
653 if (r < 0)
654 return r;
655
656 return 0;
657 }
658
mount_load_root_mount(Unit * u)659 static void mount_load_root_mount(Unit *u) {
660 assert(u);
661
662 if (!unit_has_name(u, SPECIAL_ROOT_MOUNT))
663 return;
664
665 u->perpetual = true;
666 u->default_dependencies = false;
667
668 /* The stdio/kmsg bridge socket is on /, in order to avoid a dep loop, don't use kmsg logging for -.mount */
669 MOUNT(u)->exec_context.std_output = EXEC_OUTPUT_NULL;
670 MOUNT(u)->exec_context.std_input = EXEC_INPUT_NULL;
671
672 if (!u->description)
673 u->description = strdup("Root Mount");
674 }
675
mount_load(Unit * u)676 static int mount_load(Unit *u) {
677 Mount *m = MOUNT(u);
678 int r, q = 0;
679
680 assert(m);
681 assert(u);
682 assert(u->load_state == UNIT_STUB);
683
684 mount_load_root_mount(u);
685
686 bool fragment_optional = m->from_proc_self_mountinfo || u->perpetual;
687 r = unit_load_fragment_and_dropin(u, !fragment_optional);
688
689 /* Add in some extras. Note we do this in all cases (even if we failed to load the unit) when announced by the
690 * kernel, because we need some things to be set up no matter what when the kernel establishes a mount and thus
691 * we need to update the state in our unit to track it. After all, consider that we don't allow changing the
692 * 'slice' field for a unit once it is active. */
693 if (u->load_state == UNIT_LOADED || m->from_proc_self_mountinfo || u->perpetual)
694 q = mount_add_extras(m);
695
696 if (r < 0)
697 return r;
698 if (q < 0)
699 return q;
700 if (u->load_state != UNIT_LOADED)
701 return 0;
702
703 return mount_verify(m);
704 }
705
mount_set_state(Mount * m,MountState state)706 static void mount_set_state(Mount *m, MountState state) {
707 MountState old_state;
708 assert(m);
709
710 if (m->state != state)
711 bus_unit_send_pending_change_signal(UNIT(m), false);
712
713 old_state = m->state;
714 m->state = state;
715
716 if (!MOUNT_STATE_WITH_PROCESS(state)) {
717 m->timer_event_source = sd_event_source_disable_unref(m->timer_event_source);
718 mount_unwatch_control_pid(m);
719 m->control_command = NULL;
720 m->control_command_id = _MOUNT_EXEC_COMMAND_INVALID;
721 }
722
723 if (state != old_state)
724 log_unit_debug(UNIT(m), "Changed %s -> %s", mount_state_to_string(old_state), mount_state_to_string(state));
725
726 unit_notify(UNIT(m), state_translation_table[old_state], state_translation_table[state],
727 m->reload_result == MOUNT_SUCCESS ? 0 : UNIT_NOTIFY_RELOAD_FAILURE);
728 }
729
mount_coldplug(Unit * u)730 static int mount_coldplug(Unit *u) {
731 Mount *m = MOUNT(u);
732 MountState new_state = MOUNT_DEAD;
733 int r;
734
735 assert(m);
736 assert(m->state == MOUNT_DEAD);
737
738 if (m->deserialized_state != m->state)
739 new_state = m->deserialized_state;
740 else if (m->from_proc_self_mountinfo)
741 new_state = MOUNT_MOUNTED;
742
743 if (new_state == m->state)
744 return 0;
745
746 if (m->control_pid > 0 &&
747 pid_is_unwaited(m->control_pid) &&
748 MOUNT_STATE_WITH_PROCESS(new_state)) {
749
750 r = unit_watch_pid(UNIT(m), m->control_pid, false);
751 if (r < 0)
752 return r;
753
754 r = mount_arm_timer(m, usec_add(u->state_change_timestamp.monotonic, m->timeout_usec));
755 if (r < 0)
756 return r;
757 }
758
759 if (!IN_SET(new_state, MOUNT_DEAD, MOUNT_FAILED)) {
760 (void) unit_setup_dynamic_creds(u);
761 (void) unit_setup_exec_runtime(u);
762 }
763
764 mount_set_state(m, new_state);
765 return 0;
766 }
767
mount_dump(Unit * u,FILE * f,const char * prefix)768 static void mount_dump(Unit *u, FILE *f, const char *prefix) {
769 Mount *m = MOUNT(u);
770 MountParameters *p;
771
772 assert(m);
773 assert(f);
774
775 p = get_mount_parameters(m);
776
777 fprintf(f,
778 "%sMount State: %s\n"
779 "%sResult: %s\n"
780 "%sClean Result: %s\n"
781 "%sWhere: %s\n"
782 "%sWhat: %s\n"
783 "%sFile System Type: %s\n"
784 "%sOptions: %s\n"
785 "%sFrom /proc/self/mountinfo: %s\n"
786 "%sFrom fragment: %s\n"
787 "%sExtrinsic: %s\n"
788 "%sDirectoryMode: %04o\n"
789 "%sSloppyOptions: %s\n"
790 "%sLazyUnmount: %s\n"
791 "%sForceUnmount: %s\n"
792 "%sReadWriteOnly: %s\n"
793 "%sTimeoutSec: %s\n",
794 prefix, mount_state_to_string(m->state),
795 prefix, mount_result_to_string(m->result),
796 prefix, mount_result_to_string(m->clean_result),
797 prefix, m->where,
798 prefix, p ? strna(p->what) : "n/a",
799 prefix, p ? strna(p->fstype) : "n/a",
800 prefix, p ? strna(p->options) : "n/a",
801 prefix, yes_no(m->from_proc_self_mountinfo),
802 prefix, yes_no(m->from_fragment),
803 prefix, yes_no(mount_is_extrinsic(u)),
804 prefix, m->directory_mode,
805 prefix, yes_no(m->sloppy_options),
806 prefix, yes_no(m->lazy_unmount),
807 prefix, yes_no(m->force_unmount),
808 prefix, yes_no(m->read_write_only),
809 prefix, FORMAT_TIMESPAN(m->timeout_usec, USEC_PER_SEC));
810
811 if (m->control_pid > 0)
812 fprintf(f,
813 "%sControl PID: "PID_FMT"\n",
814 prefix, m->control_pid);
815
816 exec_context_dump(&m->exec_context, f, prefix);
817 kill_context_dump(&m->kill_context, f, prefix);
818 cgroup_context_dump(UNIT(m), f, prefix);
819 }
820
mount_spawn(Mount * m,ExecCommand * c,pid_t * _pid)821 static int mount_spawn(Mount *m, ExecCommand *c, pid_t *_pid) {
822
823 _cleanup_(exec_params_clear) ExecParameters exec_params = {
824 .flags = EXEC_APPLY_SANDBOXING|EXEC_APPLY_CHROOT|EXEC_APPLY_TTY_STDIN,
825 .stdin_fd = -1,
826 .stdout_fd = -1,
827 .stderr_fd = -1,
828 .exec_fd = -1,
829 };
830 pid_t pid;
831 int r;
832
833 assert(m);
834 assert(c);
835 assert(_pid);
836
837 r = unit_prepare_exec(UNIT(m));
838 if (r < 0)
839 return r;
840
841 r = mount_arm_timer(m, usec_add(now(CLOCK_MONOTONIC), m->timeout_usec));
842 if (r < 0)
843 return r;
844
845 r = unit_set_exec_params(UNIT(m), &exec_params);
846 if (r < 0)
847 return r;
848
849 r = exec_spawn(UNIT(m),
850 c,
851 &m->exec_context,
852 &exec_params,
853 m->exec_runtime,
854 &m->dynamic_creds,
855 &pid);
856 if (r < 0)
857 return r;
858
859 r = unit_watch_pid(UNIT(m), pid, true);
860 if (r < 0)
861 return r;
862
863 *_pid = pid;
864
865 return 0;
866 }
867
mount_enter_dead(Mount * m,MountResult f)868 static void mount_enter_dead(Mount *m, MountResult f) {
869 assert(m);
870
871 if (m->result == MOUNT_SUCCESS)
872 m->result = f;
873
874 unit_log_result(UNIT(m), m->result == MOUNT_SUCCESS, mount_result_to_string(m->result));
875 unit_warn_leftover_processes(UNIT(m), unit_log_leftover_process_stop);
876
877 mount_set_state(m, m->result != MOUNT_SUCCESS ? MOUNT_FAILED : MOUNT_DEAD);
878
879 m->exec_runtime = exec_runtime_unref(m->exec_runtime, true);
880
881 unit_destroy_runtime_data(UNIT(m), &m->exec_context);
882
883 unit_unref_uid_gid(UNIT(m), true);
884
885 dynamic_creds_destroy(&m->dynamic_creds);
886
887 /* Any dependencies based on /proc/self/mountinfo are now stale */
888 unit_remove_dependencies(UNIT(m), UNIT_DEPENDENCY_MOUNTINFO_IMPLICIT);
889 }
890
mount_enter_mounted(Mount * m,MountResult f)891 static void mount_enter_mounted(Mount *m, MountResult f) {
892 assert(m);
893
894 if (m->result == MOUNT_SUCCESS)
895 m->result = f;
896
897 mount_set_state(m, MOUNT_MOUNTED);
898 }
899
mount_enter_dead_or_mounted(Mount * m,MountResult f)900 static void mount_enter_dead_or_mounted(Mount *m, MountResult f) {
901 assert(m);
902
903 /* Enter DEAD or MOUNTED state, depending on what the kernel currently says about the mount point. We use this
904 * whenever we executed an operation, so that our internal state reflects what the kernel says again, after all
905 * ultimately we just mirror the kernel's internal state on this. */
906
907 if (m->from_proc_self_mountinfo)
908 mount_enter_mounted(m, f);
909 else
910 mount_enter_dead(m, f);
911 }
912
state_to_kill_operation(MountState state)913 static int state_to_kill_operation(MountState state) {
914 switch (state) {
915
916 case MOUNT_REMOUNTING_SIGTERM:
917 return KILL_RESTART;
918
919 case MOUNT_UNMOUNTING_SIGTERM:
920 return KILL_TERMINATE;
921
922 case MOUNT_REMOUNTING_SIGKILL:
923 case MOUNT_UNMOUNTING_SIGKILL:
924 return KILL_KILL;
925
926 default:
927 return _KILL_OPERATION_INVALID;
928 }
929 }
930
mount_enter_signal(Mount * m,MountState state,MountResult f)931 static void mount_enter_signal(Mount *m, MountState state, MountResult f) {
932 int r;
933
934 assert(m);
935
936 if (m->result == MOUNT_SUCCESS)
937 m->result = f;
938
939 r = unit_kill_context(
940 UNIT(m),
941 &m->kill_context,
942 state_to_kill_operation(state),
943 -1,
944 m->control_pid,
945 false);
946 if (r < 0)
947 goto fail;
948
949 if (r > 0) {
950 r = mount_arm_timer(m, usec_add(now(CLOCK_MONOTONIC), m->timeout_usec));
951 if (r < 0)
952 goto fail;
953
954 mount_set_state(m, state);
955 } else if (state == MOUNT_REMOUNTING_SIGTERM && m->kill_context.send_sigkill)
956 mount_enter_signal(m, MOUNT_REMOUNTING_SIGKILL, MOUNT_SUCCESS);
957 else if (IN_SET(state, MOUNT_REMOUNTING_SIGTERM, MOUNT_REMOUNTING_SIGKILL))
958 mount_enter_mounted(m, MOUNT_SUCCESS);
959 else if (state == MOUNT_UNMOUNTING_SIGTERM && m->kill_context.send_sigkill)
960 mount_enter_signal(m, MOUNT_UNMOUNTING_SIGKILL, MOUNT_SUCCESS);
961 else
962 mount_enter_dead_or_mounted(m, MOUNT_SUCCESS);
963
964 return;
965
966 fail:
967 log_unit_warning_errno(UNIT(m), r, "Failed to kill processes: %m");
968 mount_enter_dead_or_mounted(m, MOUNT_FAILURE_RESOURCES);
969 }
970
mount_enter_unmounting(Mount * m)971 static void mount_enter_unmounting(Mount *m) {
972 int r;
973
974 assert(m);
975
976 /* Start counting our attempts */
977 if (!IN_SET(m->state,
978 MOUNT_UNMOUNTING,
979 MOUNT_UNMOUNTING_SIGTERM,
980 MOUNT_UNMOUNTING_SIGKILL))
981 m->n_retry_umount = 0;
982
983 m->control_command_id = MOUNT_EXEC_UNMOUNT;
984 m->control_command = m->exec_command + MOUNT_EXEC_UNMOUNT;
985
986 r = exec_command_set(m->control_command, UMOUNT_PATH, m->where, "-c", NULL);
987 if (r >= 0 && m->lazy_unmount)
988 r = exec_command_append(m->control_command, "-l", NULL);
989 if (r >= 0 && m->force_unmount)
990 r = exec_command_append(m->control_command, "-f", NULL);
991 if (r < 0)
992 goto fail;
993
994 mount_unwatch_control_pid(m);
995
996 r = mount_spawn(m, m->control_command, &m->control_pid);
997 if (r < 0)
998 goto fail;
999
1000 mount_set_state(m, MOUNT_UNMOUNTING);
1001
1002 return;
1003
1004 fail:
1005 log_unit_warning_errno(UNIT(m), r, "Failed to run 'umount' task: %m");
1006 mount_enter_dead_or_mounted(m, MOUNT_FAILURE_RESOURCES);
1007 }
1008
mount_enter_mounting(Mount * m)1009 static void mount_enter_mounting(Mount *m) {
1010 int r;
1011 MountParameters *p;
1012
1013 assert(m);
1014
1015 r = unit_fail_if_noncanonical(UNIT(m), m->where);
1016 if (r < 0)
1017 goto fail;
1018
1019 (void) mkdir_p_label(m->where, m->directory_mode);
1020
1021 unit_warn_if_dir_nonempty(UNIT(m), m->where);
1022 unit_warn_leftover_processes(UNIT(m), unit_log_leftover_process_start);
1023
1024 m->control_command_id = MOUNT_EXEC_MOUNT;
1025 m->control_command = m->exec_command + MOUNT_EXEC_MOUNT;
1026
1027 /* Create the source directory for bind-mounts if needed */
1028 p = get_mount_parameters_fragment(m);
1029 if (p && mount_is_bind(p)) {
1030 r = mkdir_p_label(p->what, m->directory_mode);
1031 /* mkdir_p_label() can return -EEXIST if the target path exists and is not a directory - which is
1032 * totally OK, in case the user wants us to overmount a non-directory inode. */
1033 if (r < 0 && r != -EEXIST) {
1034 log_unit_error_errno(UNIT(m), r, "Failed to make bind mount source '%s': %m", p->what);
1035 goto fail;
1036 }
1037 }
1038
1039 if (p) {
1040 _cleanup_free_ char *opts = NULL;
1041
1042 r = fstab_filter_options(p->options, "nofail\0" "noauto\0" "auto\0", NULL, NULL, NULL, &opts);
1043 if (r < 0)
1044 goto fail;
1045
1046 r = exec_command_set(m->control_command, MOUNT_PATH, p->what, m->where, NULL);
1047 if (r >= 0 && m->sloppy_options)
1048 r = exec_command_append(m->control_command, "-s", NULL);
1049 if (r >= 0 && m->read_write_only)
1050 r = exec_command_append(m->control_command, "-w", NULL);
1051 if (r >= 0 && p->fstype)
1052 r = exec_command_append(m->control_command, "-t", p->fstype, NULL);
1053 if (r >= 0 && !isempty(opts))
1054 r = exec_command_append(m->control_command, "-o", opts, NULL);
1055 } else
1056 r = -ENOENT;
1057 if (r < 0)
1058 goto fail;
1059
1060 mount_unwatch_control_pid(m);
1061
1062 r = mount_spawn(m, m->control_command, &m->control_pid);
1063 if (r < 0)
1064 goto fail;
1065
1066 mount_set_state(m, MOUNT_MOUNTING);
1067
1068 return;
1069
1070 fail:
1071 log_unit_warning_errno(UNIT(m), r, "Failed to run 'mount' task: %m");
1072 mount_enter_dead_or_mounted(m, MOUNT_FAILURE_RESOURCES);
1073 }
1074
mount_set_reload_result(Mount * m,MountResult result)1075 static void mount_set_reload_result(Mount *m, MountResult result) {
1076 assert(m);
1077
1078 /* Only store the first error we encounter */
1079 if (m->reload_result != MOUNT_SUCCESS)
1080 return;
1081
1082 m->reload_result = result;
1083 }
1084
mount_enter_remounting(Mount * m)1085 static void mount_enter_remounting(Mount *m) {
1086 int r;
1087 MountParameters *p;
1088
1089 assert(m);
1090
1091 /* Reset reload result when we are about to start a new remount operation */
1092 m->reload_result = MOUNT_SUCCESS;
1093
1094 m->control_command_id = MOUNT_EXEC_REMOUNT;
1095 m->control_command = m->exec_command + MOUNT_EXEC_REMOUNT;
1096
1097 p = get_mount_parameters_fragment(m);
1098 if (p) {
1099 const char *o;
1100
1101 if (p->options)
1102 o = strjoina("remount,", p->options);
1103 else
1104 o = "remount";
1105
1106 r = exec_command_set(m->control_command, MOUNT_PATH,
1107 p->what, m->where,
1108 "-o", o, NULL);
1109 if (r >= 0 && m->sloppy_options)
1110 r = exec_command_append(m->control_command, "-s", NULL);
1111 if (r >= 0 && m->read_write_only)
1112 r = exec_command_append(m->control_command, "-w", NULL);
1113 if (r >= 0 && p->fstype)
1114 r = exec_command_append(m->control_command, "-t", p->fstype, NULL);
1115 } else
1116 r = -ENOENT;
1117 if (r < 0)
1118 goto fail;
1119
1120 mount_unwatch_control_pid(m);
1121
1122 r = mount_spawn(m, m->control_command, &m->control_pid);
1123 if (r < 0)
1124 goto fail;
1125
1126 mount_set_state(m, MOUNT_REMOUNTING);
1127
1128 return;
1129
1130 fail:
1131 log_unit_warning_errno(UNIT(m), r, "Failed to run 'remount' task: %m");
1132 mount_set_reload_result(m, MOUNT_FAILURE_RESOURCES);
1133 mount_enter_dead_or_mounted(m, MOUNT_SUCCESS);
1134 }
1135
mount_cycle_clear(Mount * m)1136 static void mount_cycle_clear(Mount *m) {
1137 assert(m);
1138
1139 /* Clear all state we shall forget for this new cycle */
1140
1141 m->result = MOUNT_SUCCESS;
1142 m->reload_result = MOUNT_SUCCESS;
1143 exec_command_reset_status_array(m->exec_command, _MOUNT_EXEC_COMMAND_MAX);
1144 UNIT(m)->reset_accounting = true;
1145 }
1146
mount_start(Unit * u)1147 static int mount_start(Unit *u) {
1148 Mount *m = MOUNT(u);
1149 int r;
1150
1151 assert(m);
1152
1153 /* We cannot fulfill this request right now, try again later
1154 * please! */
1155 if (IN_SET(m->state,
1156 MOUNT_UNMOUNTING,
1157 MOUNT_UNMOUNTING_SIGTERM,
1158 MOUNT_UNMOUNTING_SIGKILL,
1159 MOUNT_CLEANING))
1160 return -EAGAIN;
1161
1162 /* Already on it! */
1163 if (IN_SET(m->state, MOUNT_MOUNTING, MOUNT_MOUNTING_DONE))
1164 return 0;
1165
1166 assert(IN_SET(m->state, MOUNT_DEAD, MOUNT_FAILED));
1167
1168 r = unit_acquire_invocation_id(u);
1169 if (r < 0)
1170 return r;
1171
1172 mount_cycle_clear(m);
1173 mount_enter_mounting(m);
1174
1175 return 1;
1176 }
1177
mount_stop(Unit * u)1178 static int mount_stop(Unit *u) {
1179 Mount *m = MOUNT(u);
1180
1181 assert(m);
1182
1183 switch (m->state) {
1184
1185 case MOUNT_UNMOUNTING:
1186 case MOUNT_UNMOUNTING_SIGKILL:
1187 case MOUNT_UNMOUNTING_SIGTERM:
1188 /* Already on it */
1189 return 0;
1190
1191 case MOUNT_MOUNTING:
1192 case MOUNT_MOUNTING_DONE:
1193 case MOUNT_REMOUNTING:
1194 /* If we are still waiting for /bin/mount, we go directly into kill mode. */
1195 mount_enter_signal(m, MOUNT_UNMOUNTING_SIGTERM, MOUNT_SUCCESS);
1196 return 0;
1197
1198 case MOUNT_REMOUNTING_SIGTERM:
1199 /* If we are already waiting for a hung remount, convert this to the matching unmounting state */
1200 mount_set_state(m, MOUNT_UNMOUNTING_SIGTERM);
1201 return 0;
1202
1203 case MOUNT_REMOUNTING_SIGKILL:
1204 /* as above */
1205 mount_set_state(m, MOUNT_UNMOUNTING_SIGKILL);
1206 return 0;
1207
1208 case MOUNT_MOUNTED:
1209 mount_enter_unmounting(m);
1210 return 1;
1211
1212 case MOUNT_CLEANING:
1213 /* If we are currently cleaning, then abort it, brutally. */
1214 mount_enter_signal(m, MOUNT_UNMOUNTING_SIGKILL, MOUNT_SUCCESS);
1215 return 0;
1216
1217 default:
1218 assert_not_reached();
1219 }
1220 }
1221
mount_reload(Unit * u)1222 static int mount_reload(Unit *u) {
1223 Mount *m = MOUNT(u);
1224
1225 assert(m);
1226 assert(m->state == MOUNT_MOUNTED);
1227
1228 mount_enter_remounting(m);
1229
1230 return 1;
1231 }
1232
mount_serialize(Unit * u,FILE * f,FDSet * fds)1233 static int mount_serialize(Unit *u, FILE *f, FDSet *fds) {
1234 Mount *m = MOUNT(u);
1235
1236 assert(m);
1237 assert(f);
1238 assert(fds);
1239
1240 (void) serialize_item(f, "state", mount_state_to_string(m->state));
1241 (void) serialize_item(f, "result", mount_result_to_string(m->result));
1242 (void) serialize_item(f, "reload-result", mount_result_to_string(m->reload_result));
1243 (void) serialize_item_format(f, "n-retry-umount", "%u", m->n_retry_umount);
1244
1245 if (m->control_pid > 0)
1246 (void) serialize_item_format(f, "control-pid", PID_FMT, m->control_pid);
1247
1248 if (m->control_command_id >= 0)
1249 (void) serialize_item(f, "control-command", mount_exec_command_to_string(m->control_command_id));
1250
1251 return 0;
1252 }
1253
mount_deserialize_item(Unit * u,const char * key,const char * value,FDSet * fds)1254 static int mount_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
1255 Mount *m = MOUNT(u);
1256 int r;
1257
1258 assert(m);
1259 assert(u);
1260 assert(key);
1261 assert(value);
1262 assert(fds);
1263
1264 if (streq(key, "state")) {
1265 MountState state;
1266
1267 state = mount_state_from_string(value);
1268 if (state < 0)
1269 log_unit_debug_errno(u, state, "Failed to parse state value: %s", value);
1270 else
1271 m->deserialized_state = state;
1272
1273 } else if (streq(key, "result")) {
1274 MountResult f;
1275
1276 f = mount_result_from_string(value);
1277 if (f < 0)
1278 log_unit_debug_errno(u, f, "Failed to parse result value: %s", value);
1279 else if (f != MOUNT_SUCCESS)
1280 m->result = f;
1281
1282 } else if (streq(key, "reload-result")) {
1283 MountResult f;
1284
1285 f = mount_result_from_string(value);
1286 if (f < 0)
1287 log_unit_debug_errno(u, f, "Failed to parse reload result value: %s", value);
1288 else if (f != MOUNT_SUCCESS)
1289 m->reload_result = f;
1290
1291 } else if (streq(key, "n-retry-umount")) {
1292
1293 r = safe_atou(value, &m->n_retry_umount);
1294 if (r < 0)
1295 log_unit_debug_errno(u, r, "Failed to parse n-retry-umount value: %s", value);
1296
1297 } else if (streq(key, "control-pid")) {
1298
1299 r = parse_pid(value, &m->control_pid);
1300 if (r < 0)
1301 log_unit_debug_errno(u, r, "Failed to parse control-pid value: %s", value);
1302
1303 } else if (streq(key, "control-command")) {
1304 MountExecCommand id;
1305
1306 id = mount_exec_command_from_string(value);
1307 if (id < 0)
1308 log_unit_debug_errno(u, id, "Failed to parse exec-command value: %s", value);
1309 else {
1310 m->control_command_id = id;
1311 m->control_command = m->exec_command + id;
1312 }
1313 } else
1314 log_unit_debug(u, "Unknown serialization key: %s", key);
1315
1316 return 0;
1317 }
1318
mount_active_state(Unit * u)1319 _pure_ static UnitActiveState mount_active_state(Unit *u) {
1320 assert(u);
1321
1322 return state_translation_table[MOUNT(u)->state];
1323 }
1324
mount_sub_state_to_string(Unit * u)1325 _pure_ static const char *mount_sub_state_to_string(Unit *u) {
1326 assert(u);
1327
1328 return mount_state_to_string(MOUNT(u)->state);
1329 }
1330
mount_may_gc(Unit * u)1331 _pure_ static bool mount_may_gc(Unit *u) {
1332 Mount *m = MOUNT(u);
1333
1334 assert(m);
1335
1336 if (m->from_proc_self_mountinfo)
1337 return false;
1338
1339 return true;
1340 }
1341
mount_sigchld_event(Unit * u,pid_t pid,int code,int status)1342 static void mount_sigchld_event(Unit *u, pid_t pid, int code, int status) {
1343 Mount *m = MOUNT(u);
1344 MountResult f;
1345
1346 assert(m);
1347 assert(pid >= 0);
1348
1349 if (pid != m->control_pid)
1350 return;
1351
1352 /* So here's the thing, we really want to know before /usr/bin/mount or /usr/bin/umount exit whether
1353 * they established/remove a mount. This is important when mounting, but even more so when unmounting
1354 * since we need to deal with nested mounts and otherwise cannot safely determine whether to repeat
1355 * the unmounts. In theory, the kernel fires /proc/self/mountinfo changes off before returning from
1356 * the mount() or umount() syscalls, and thus we should see the changes to the proc file before we
1357 * process the waitid() for the /usr/bin/(u)mount processes. However, this is unfortunately racy: we
1358 * have to waitid() for processes using P_ALL (since we need to reap unexpected children that got
1359 * reparented to PID 1), but when using P_ALL we might end up reaping processes that terminated just
1360 * instants ago, i.e. already after our last event loop iteration (i.e. after the last point we might
1361 * have noticed /proc/self/mountinfo events via epoll). This means event loop priorities for
1362 * processing SIGCHLD vs. /proc/self/mountinfo IO events are not as relevant as we want. To fix that
1363 * race, let's explicitly scan /proc/self/mountinfo before we start processing /usr/bin/(u)mount
1364 * dying. It's ugly, but it makes our ordering systematic again, and makes sure we always see
1365 * /proc/self/mountinfo changes before our mount/umount exits. */
1366 (void) mount_process_proc_self_mountinfo(u->manager);
1367
1368 m->control_pid = 0;
1369
1370 if (is_clean_exit(code, status, EXIT_CLEAN_COMMAND, NULL))
1371 f = MOUNT_SUCCESS;
1372 else if (code == CLD_EXITED)
1373 f = MOUNT_FAILURE_EXIT_CODE;
1374 else if (code == CLD_KILLED)
1375 f = MOUNT_FAILURE_SIGNAL;
1376 else if (code == CLD_DUMPED)
1377 f = MOUNT_FAILURE_CORE_DUMP;
1378 else
1379 assert_not_reached();
1380
1381 if (IN_SET(m->state, MOUNT_REMOUNTING, MOUNT_REMOUNTING_SIGKILL, MOUNT_REMOUNTING_SIGTERM))
1382 mount_set_reload_result(m, f);
1383 else if (m->result == MOUNT_SUCCESS)
1384 m->result = f;
1385
1386 if (m->control_command) {
1387 exec_status_exit(&m->control_command->exec_status, &m->exec_context, pid, code, status);
1388
1389 m->control_command = NULL;
1390 m->control_command_id = _MOUNT_EXEC_COMMAND_INVALID;
1391 }
1392
1393 unit_log_process_exit(
1394 u,
1395 "Mount process",
1396 mount_exec_command_to_string(m->control_command_id),
1397 f == MOUNT_SUCCESS,
1398 code, status);
1399
1400 /* Note that due to the io event priority logic, we can be sure the new mountinfo is loaded
1401 * before we process the SIGCHLD for the mount command. */
1402
1403 switch (m->state) {
1404
1405 case MOUNT_MOUNTING:
1406 /* Our mount point has not appeared in mountinfo. Something went wrong. */
1407
1408 if (f == MOUNT_SUCCESS) {
1409 /* Either /bin/mount has an unexpected definition of success,
1410 * or someone raced us and we lost. */
1411 log_unit_warning(UNIT(m), "Mount process finished, but there is no mount.");
1412 f = MOUNT_FAILURE_PROTOCOL;
1413 }
1414 mount_enter_dead(m, f);
1415 break;
1416
1417 case MOUNT_MOUNTING_DONE:
1418 mount_enter_mounted(m, f);
1419 break;
1420
1421 case MOUNT_REMOUNTING:
1422 case MOUNT_REMOUNTING_SIGTERM:
1423 case MOUNT_REMOUNTING_SIGKILL:
1424 mount_enter_dead_or_mounted(m, MOUNT_SUCCESS);
1425 break;
1426
1427 case MOUNT_UNMOUNTING:
1428
1429 if (f == MOUNT_SUCCESS && m->from_proc_self_mountinfo) {
1430
1431 /* Still a mount point? If so, let's try again. Most likely there were multiple mount points
1432 * stacked on top of each other. We might exceed the timeout specified by the user overall,
1433 * but we will stop as soon as any one umount times out. */
1434
1435 if (m->n_retry_umount < RETRY_UMOUNT_MAX) {
1436 log_unit_debug(u, "Mount still present, trying again.");
1437 m->n_retry_umount++;
1438 mount_enter_unmounting(m);
1439 } else {
1440 log_unit_warning(u, "Mount still present after %u attempts to unmount, giving up.", m->n_retry_umount);
1441 mount_enter_mounted(m, f);
1442 }
1443 } else
1444 mount_enter_dead_or_mounted(m, f);
1445
1446 break;
1447
1448 case MOUNT_UNMOUNTING_SIGKILL:
1449 case MOUNT_UNMOUNTING_SIGTERM:
1450 mount_enter_dead_or_mounted(m, f);
1451 break;
1452
1453 case MOUNT_CLEANING:
1454 if (m->clean_result == MOUNT_SUCCESS)
1455 m->clean_result = f;
1456
1457 mount_enter_dead(m, MOUNT_SUCCESS);
1458 break;
1459
1460 default:
1461 assert_not_reached();
1462 }
1463
1464 /* Notify clients about changed exit status */
1465 unit_add_to_dbus_queue(u);
1466 }
1467
mount_dispatch_timer(sd_event_source * source,usec_t usec,void * userdata)1468 static int mount_dispatch_timer(sd_event_source *source, usec_t usec, void *userdata) {
1469 Mount *m = MOUNT(userdata);
1470
1471 assert(m);
1472 assert(m->timer_event_source == source);
1473
1474 switch (m->state) {
1475
1476 case MOUNT_MOUNTING:
1477 case MOUNT_MOUNTING_DONE:
1478 log_unit_warning(UNIT(m), "Mounting timed out. Terminating.");
1479 mount_enter_signal(m, MOUNT_UNMOUNTING_SIGTERM, MOUNT_FAILURE_TIMEOUT);
1480 break;
1481
1482 case MOUNT_REMOUNTING:
1483 log_unit_warning(UNIT(m), "Remounting timed out. Terminating remount process.");
1484 mount_set_reload_result(m, MOUNT_FAILURE_TIMEOUT);
1485 mount_enter_signal(m, MOUNT_REMOUNTING_SIGTERM, MOUNT_SUCCESS);
1486 break;
1487
1488 case MOUNT_REMOUNTING_SIGTERM:
1489 mount_set_reload_result(m, MOUNT_FAILURE_TIMEOUT);
1490
1491 if (m->kill_context.send_sigkill) {
1492 log_unit_warning(UNIT(m), "Remounting timed out. Killing.");
1493 mount_enter_signal(m, MOUNT_REMOUNTING_SIGKILL, MOUNT_SUCCESS);
1494 } else {
1495 log_unit_warning(UNIT(m), "Remounting timed out. Skipping SIGKILL. Ignoring.");
1496 mount_enter_dead_or_mounted(m, MOUNT_SUCCESS);
1497 }
1498 break;
1499
1500 case MOUNT_REMOUNTING_SIGKILL:
1501 mount_set_reload_result(m, MOUNT_FAILURE_TIMEOUT);
1502
1503 log_unit_warning(UNIT(m), "Mount process still around after SIGKILL. Ignoring.");
1504 mount_enter_dead_or_mounted(m, MOUNT_SUCCESS);
1505 break;
1506
1507 case MOUNT_UNMOUNTING:
1508 log_unit_warning(UNIT(m), "Unmounting timed out. Terminating.");
1509 mount_enter_signal(m, MOUNT_UNMOUNTING_SIGTERM, MOUNT_FAILURE_TIMEOUT);
1510 break;
1511
1512 case MOUNT_UNMOUNTING_SIGTERM:
1513 if (m->kill_context.send_sigkill) {
1514 log_unit_warning(UNIT(m), "Mount process timed out. Killing.");
1515 mount_enter_signal(m, MOUNT_UNMOUNTING_SIGKILL, MOUNT_FAILURE_TIMEOUT);
1516 } else {
1517 log_unit_warning(UNIT(m), "Mount process timed out. Skipping SIGKILL. Ignoring.");
1518 mount_enter_dead_or_mounted(m, MOUNT_FAILURE_TIMEOUT);
1519 }
1520 break;
1521
1522 case MOUNT_UNMOUNTING_SIGKILL:
1523 log_unit_warning(UNIT(m), "Mount process still around after SIGKILL. Ignoring.");
1524 mount_enter_dead_or_mounted(m, MOUNT_FAILURE_TIMEOUT);
1525 break;
1526
1527 case MOUNT_CLEANING:
1528 log_unit_warning(UNIT(m), "Cleaning timed out. killing.");
1529
1530 if (m->clean_result == MOUNT_SUCCESS)
1531 m->clean_result = MOUNT_FAILURE_TIMEOUT;
1532
1533 mount_enter_signal(m, MOUNT_UNMOUNTING_SIGKILL, 0);
1534 break;
1535
1536 default:
1537 assert_not_reached();
1538 }
1539
1540 return 0;
1541 }
1542
mount_setup_new_unit(Manager * m,const char * name,const char * what,const char * where,const char * options,const char * fstype,MountProcFlags * ret_flags,Unit ** ret)1543 static int mount_setup_new_unit(
1544 Manager *m,
1545 const char *name,
1546 const char *what,
1547 const char *where,
1548 const char *options,
1549 const char *fstype,
1550 MountProcFlags *ret_flags,
1551 Unit **ret) {
1552
1553 _cleanup_(unit_freep) Unit *u = NULL;
1554 int r;
1555
1556 assert(m);
1557 assert(name);
1558 assert(ret_flags);
1559 assert(ret);
1560
1561 r = unit_new_for_name(m, sizeof(Mount), name, &u);
1562 if (r < 0)
1563 return r;
1564
1565 r = free_and_strdup(&u->source_path, "/proc/self/mountinfo");
1566 if (r < 0)
1567 return r;
1568
1569 r = free_and_strdup(&MOUNT(u)->where, where);
1570 if (r < 0)
1571 return r;
1572
1573 r = update_parameters_proc_self_mountinfo(MOUNT(u), what, options, fstype);
1574 if (r < 0)
1575 return r;
1576
1577 r = mount_add_non_exec_dependencies(MOUNT(u));
1578 if (r < 0)
1579 return r;
1580
1581 /* This unit was generated because /proc/self/mountinfo reported it. Remember this, so that by the time we load
1582 * the unit file for it (and thus add in extra deps right after) we know what source to attributes the deps
1583 * to. */
1584 MOUNT(u)->from_proc_self_mountinfo = true;
1585
1586 /* We have only allocated the stub now, let's enqueue this unit for loading now, so that everything else is
1587 * loaded in now. */
1588 unit_add_to_load_queue(u);
1589
1590 *ret_flags = MOUNT_PROC_IS_MOUNTED | MOUNT_PROC_JUST_MOUNTED | MOUNT_PROC_JUST_CHANGED;
1591 *ret = TAKE_PTR(u);
1592 return 0;
1593 }
1594
mount_setup_existing_unit(Unit * u,const char * what,const char * where,const char * options,const char * fstype,MountProcFlags * ret_flags)1595 static int mount_setup_existing_unit(
1596 Unit *u,
1597 const char *what,
1598 const char *where,
1599 const char *options,
1600 const char *fstype,
1601 MountProcFlags *ret_flags) {
1602
1603 int r;
1604
1605 assert(u);
1606 assert(ret_flags);
1607
1608 if (!MOUNT(u)->where) {
1609 MOUNT(u)->where = strdup(where);
1610 if (!MOUNT(u)->where)
1611 return -ENOMEM;
1612 }
1613
1614 /* In case we have multiple mounts established on the same mount point, let's merge flags set already
1615 * for the current unit. Note that the flags field is reset on each iteration of reading
1616 * /proc/self/mountinfo, hence we know for sure anything already set here is from the current
1617 * iteration and thus worthy of taking into account. */
1618 MountProcFlags flags =
1619 MOUNT(u)->proc_flags | MOUNT_PROC_IS_MOUNTED;
1620
1621 r = update_parameters_proc_self_mountinfo(MOUNT(u), what, options, fstype);
1622 if (r < 0)
1623 return r;
1624 if (r > 0)
1625 flags |= MOUNT_PROC_JUST_CHANGED;
1626
1627 /* There are two conditions when we consider a mount point just mounted: when we haven't seen it in
1628 * /proc/self/mountinfo before or when MOUNT_MOUNTING is our current state. Why bother with the
1629 * latter? Shouldn't that be covered by the former? No, during reload it is not because we might then
1630 * encounter a new /proc/self/mountinfo in combination with an old mount unit state (since it stems
1631 * from the serialized state), and need to catch up. Since we know that the MOUNT_MOUNTING state is
1632 * reached when we wait for the mount to appear we hence can assume that if we are in it, we are
1633 * actually seeing it established for the first time. */
1634 if (!MOUNT(u)->from_proc_self_mountinfo || MOUNT(u)->state == MOUNT_MOUNTING)
1635 flags |= MOUNT_PROC_JUST_MOUNTED;
1636
1637 MOUNT(u)->from_proc_self_mountinfo = true;
1638
1639 if (IN_SET(u->load_state, UNIT_NOT_FOUND, UNIT_BAD_SETTING, UNIT_ERROR)) {
1640 /* The unit was previously not found or otherwise not loaded. Now that the unit shows up in
1641 * /proc/self/mountinfo we should reconsider it this, hence set it to UNIT_LOADED. */
1642 u->load_state = UNIT_LOADED;
1643 u->load_error = 0;
1644
1645 flags |= MOUNT_PROC_JUST_CHANGED;
1646 }
1647
1648 if (FLAGS_SET(flags, MOUNT_PROC_JUST_CHANGED)) {
1649 /* If things changed, then make sure that all deps are regenerated. Let's
1650 * first remove all automatic deps, and then add in the new ones. */
1651
1652 unit_remove_dependencies(u, UNIT_DEPENDENCY_MOUNTINFO_IMPLICIT);
1653
1654 r = mount_add_non_exec_dependencies(MOUNT(u));
1655 if (r < 0)
1656 return r;
1657 }
1658
1659 *ret_flags = flags;
1660 return 0;
1661 }
1662
mount_setup_unit(Manager * m,const char * what,const char * where,const char * options,const char * fstype,bool set_flags)1663 static int mount_setup_unit(
1664 Manager *m,
1665 const char *what,
1666 const char *where,
1667 const char *options,
1668 const char *fstype,
1669 bool set_flags) {
1670
1671 _cleanup_free_ char *e = NULL;
1672 MountProcFlags flags;
1673 Unit *u;
1674 int r;
1675
1676 assert(m);
1677 assert(what);
1678 assert(where);
1679 assert(options);
1680 assert(fstype);
1681
1682 /* Ignore API mount points. They should never be referenced in
1683 * dependencies ever. */
1684 if (mount_point_is_api(where) || mount_point_ignore(where))
1685 return 0;
1686
1687 if (streq(fstype, "autofs"))
1688 return 0;
1689
1690 /* probably some kind of swap, ignore */
1691 if (!is_path(where))
1692 return 0;
1693
1694 /* Mount unit names have to be (like all other unit names) short enough to fit into file names. This
1695 * means there's a good chance that overly long mount point paths after mangling them to look like a
1696 * unit name would result in unit names we don't actually consider valid. This should be OK however
1697 * as such long mount point paths should not happen on regular systems — and if they appear
1698 * nonetheless they are generally synthesized by software, and thus managed by that other
1699 * software. Having such long names just means you cannot use systemd to manage those specific mount
1700 * points, which should be an OK restriction to make. After all we don't have to be able to manage
1701 * all mount points in the world — as long as we don't choke on them when we encounter them. */
1702 r = unit_name_from_path(where, ".mount", &e);
1703 if (r < 0) {
1704 static RateLimit rate_limit = { /* Let's log about this at warning level at most once every
1705 * 5s. Given that we generate this whenever we read the file
1706 * otherwise we probably shouldn't flood the logs with
1707 * this */
1708 .interval = 5 * USEC_PER_SEC,
1709 .burst = 1,
1710 };
1711
1712 if (r == -ENAMETOOLONG)
1713 return log_struct_errno(
1714 ratelimit_below(&rate_limit) ? LOG_WARNING : LOG_DEBUG, r,
1715 "MESSAGE_ID=" SD_MESSAGE_MOUNT_POINT_PATH_NOT_SUITABLE_STR,
1716 "MOUNT_POINT=%s", where,
1717 LOG_MESSAGE("Mount point path '%s' too long to fit into unit name, ignoring mount point.", where));
1718
1719 return log_struct_errno(
1720 ratelimit_below(&rate_limit) ? LOG_WARNING : LOG_DEBUG, r,
1721 "MESSAGE_ID=" SD_MESSAGE_MOUNT_POINT_PATH_NOT_SUITABLE_STR,
1722 "MOUNT_POINT=%s", where,
1723 LOG_MESSAGE("Failed to generate valid unit name from mount point path '%s', ignoring mount point: %m", where));
1724 }
1725
1726 u = manager_get_unit(m, e);
1727 if (u)
1728 r = mount_setup_existing_unit(u, what, where, options, fstype, &flags);
1729 else
1730 /* First time we see this mount point meaning that it's not been initiated by a mount unit but rather
1731 * by the sysadmin having called mount(8) directly. */
1732 r = mount_setup_new_unit(m, e, what, where, options, fstype, &flags, &u);
1733 if (r < 0)
1734 return log_warning_errno(r, "Failed to set up mount unit for '%s': %m", where);
1735
1736 /* If the mount changed properties or state, let's notify our clients */
1737 if (flags & (MOUNT_PROC_JUST_CHANGED|MOUNT_PROC_JUST_MOUNTED))
1738 unit_add_to_dbus_queue(u);
1739
1740 if (set_flags)
1741 MOUNT(u)->proc_flags = flags;
1742
1743 return 0;
1744 }
1745
mount_load_proc_self_mountinfo(Manager * m,bool set_flags)1746 static int mount_load_proc_self_mountinfo(Manager *m, bool set_flags) {
1747 _cleanup_(mnt_free_tablep) struct libmnt_table *table = NULL;
1748 _cleanup_(mnt_free_iterp) struct libmnt_iter *iter = NULL;
1749 int r;
1750
1751 assert(m);
1752
1753 r = libmount_parse(NULL, NULL, &table, &iter);
1754 if (r < 0)
1755 return log_error_errno(r, "Failed to parse /proc/self/mountinfo: %m");
1756
1757 for (;;) {
1758 struct libmnt_fs *fs;
1759 const char *device, *path, *options, *fstype;
1760
1761 r = mnt_table_next_fs(table, iter, &fs);
1762 if (r == 1)
1763 break;
1764 if (r < 0)
1765 return log_error_errno(r, "Failed to get next entry from /proc/self/mountinfo: %m");
1766
1767 device = mnt_fs_get_source(fs);
1768 path = mnt_fs_get_target(fs);
1769 options = mnt_fs_get_options(fs);
1770 fstype = mnt_fs_get_fstype(fs);
1771
1772 if (!device || !path)
1773 continue;
1774
1775 device_found_node(m, device, DEVICE_FOUND_MOUNT, DEVICE_FOUND_MOUNT);
1776
1777 (void) mount_setup_unit(m, device, path, options, fstype, set_flags);
1778 }
1779
1780 return 0;
1781 }
1782
mount_shutdown(Manager * m)1783 static void mount_shutdown(Manager *m) {
1784 assert(m);
1785
1786 m->mount_event_source = sd_event_source_disable_unref(m->mount_event_source);
1787
1788 mnt_unref_monitor(m->mount_monitor);
1789 m->mount_monitor = NULL;
1790 }
1791
mount_get_timeout(Unit * u,usec_t * timeout)1792 static int mount_get_timeout(Unit *u, usec_t *timeout) {
1793 Mount *m = MOUNT(u);
1794 usec_t t;
1795 int r;
1796
1797 assert(m);
1798 assert(u);
1799
1800 if (!m->timer_event_source)
1801 return 0;
1802
1803 r = sd_event_source_get_time(m->timer_event_source, &t);
1804 if (r < 0)
1805 return r;
1806 if (t == USEC_INFINITY)
1807 return 0;
1808
1809 *timeout = t;
1810 return 1;
1811 }
1812
mount_enumerate_perpetual(Manager * m)1813 static void mount_enumerate_perpetual(Manager *m) {
1814 Unit *u;
1815 int r;
1816
1817 assert(m);
1818
1819 /* Whatever happens, we know for sure that the root directory is around, and cannot go away. Let's
1820 * unconditionally synthesize it here and mark it as perpetual. */
1821
1822 u = manager_get_unit(m, SPECIAL_ROOT_MOUNT);
1823 if (!u) {
1824 r = unit_new_for_name(m, sizeof(Mount), SPECIAL_ROOT_MOUNT, &u);
1825 if (r < 0) {
1826 log_error_errno(r, "Failed to allocate the special " SPECIAL_ROOT_MOUNT " unit: %m");
1827 return;
1828 }
1829 }
1830
1831 u->perpetual = true;
1832 MOUNT(u)->deserialized_state = MOUNT_MOUNTED;
1833
1834 unit_add_to_load_queue(u);
1835 unit_add_to_dbus_queue(u);
1836 }
1837
mount_is_mounted(Mount * m)1838 static bool mount_is_mounted(Mount *m) {
1839 assert(m);
1840
1841 return UNIT(m)->perpetual || FLAGS_SET(m->proc_flags, MOUNT_PROC_IS_MOUNTED);
1842 }
1843
mount_on_ratelimit_expire(sd_event_source * s,void * userdata)1844 static int mount_on_ratelimit_expire(sd_event_source *s, void *userdata) {
1845 Manager *m = userdata;
1846 Job *j;
1847
1848 assert(m);
1849
1850 /* Let's enqueue all start jobs that were previously skipped because of active ratelimit. */
1851 HASHMAP_FOREACH(j, m->jobs) {
1852 if (j->unit->type != UNIT_MOUNT)
1853 continue;
1854
1855 job_add_to_run_queue(j);
1856 }
1857
1858 /* By entering ratelimited state we made all mount start jobs not runnable, now rate limit is over so
1859 * let's make sure we dispatch them in the next iteration. */
1860 manager_trigger_run_queue(m);
1861
1862 return 0;
1863 }
1864
mount_enumerate(Manager * m)1865 static void mount_enumerate(Manager *m) {
1866 int r;
1867
1868 assert(m);
1869
1870 mnt_init_debug(0);
1871
1872 if (!m->mount_monitor) {
1873 int fd;
1874
1875 m->mount_monitor = mnt_new_monitor();
1876 if (!m->mount_monitor) {
1877 log_oom();
1878 goto fail;
1879 }
1880
1881 r = mnt_monitor_enable_kernel(m->mount_monitor, 1);
1882 if (r < 0) {
1883 log_error_errno(r, "Failed to enable watching of kernel mount events: %m");
1884 goto fail;
1885 }
1886
1887 r = mnt_monitor_enable_userspace(m->mount_monitor, 1, NULL);
1888 if (r < 0) {
1889 log_error_errno(r, "Failed to enable watching of userspace mount events: %m");
1890 goto fail;
1891 }
1892
1893 /* mnt_unref_monitor() will close the fd */
1894 fd = r = mnt_monitor_get_fd(m->mount_monitor);
1895 if (r < 0) {
1896 log_error_errno(r, "Failed to acquire watch file descriptor: %m");
1897 goto fail;
1898 }
1899
1900 r = sd_event_add_io(m->event, &m->mount_event_source, fd, EPOLLIN, mount_dispatch_io, m);
1901 if (r < 0) {
1902 log_error_errno(r, "Failed to watch mount file descriptor: %m");
1903 goto fail;
1904 }
1905
1906 r = sd_event_source_set_priority(m->mount_event_source, SD_EVENT_PRIORITY_NORMAL-10);
1907 if (r < 0) {
1908 log_error_errno(r, "Failed to adjust mount watch priority: %m");
1909 goto fail;
1910 }
1911
1912 r = sd_event_source_set_ratelimit(m->mount_event_source, 1 * USEC_PER_SEC, 5);
1913 if (r < 0) {
1914 log_error_errno(r, "Failed to enable rate limit for mount events: %m");
1915 goto fail;
1916 }
1917
1918 r = sd_event_source_set_ratelimit_expire_callback(m->mount_event_source, mount_on_ratelimit_expire);
1919 if (r < 0) {
1920 log_error_errno(r, "Failed to enable rate limit for mount events: %m");
1921 goto fail;
1922 }
1923
1924 (void) sd_event_source_set_description(m->mount_event_source, "mount-monitor-dispatch");
1925 }
1926
1927 r = mount_load_proc_self_mountinfo(m, false);
1928 if (r < 0)
1929 goto fail;
1930
1931 return;
1932
1933 fail:
1934 mount_shutdown(m);
1935 }
1936
drain_libmount(Manager * m)1937 static int drain_libmount(Manager *m) {
1938 bool rescan = false;
1939 int r;
1940
1941 assert(m);
1942
1943 /* Drain all events and verify that the event is valid.
1944 *
1945 * Note that libmount also monitors /run/mount mkdir if the directory does not exist yet. The mkdir
1946 * may generate event which is irrelevant for us.
1947 *
1948 * error: r < 0; valid: r == 0, false positive: r == 1 */
1949 do {
1950 r = mnt_monitor_next_change(m->mount_monitor, NULL, NULL);
1951 if (r < 0)
1952 return log_error_errno(r, "Failed to drain libmount events: %m");
1953 if (r == 0)
1954 rescan = true;
1955 } while (r == 0);
1956
1957 return rescan;
1958 }
1959
mount_process_proc_self_mountinfo(Manager * m)1960 static int mount_process_proc_self_mountinfo(Manager *m) {
1961 _cleanup_set_free_free_ Set *around = NULL, *gone = NULL;
1962 const char *what;
1963 int r;
1964
1965 assert(m);
1966
1967 r = drain_libmount(m);
1968 if (r <= 0)
1969 return r;
1970
1971 r = mount_load_proc_self_mountinfo(m, true);
1972 if (r < 0) {
1973 /* Reset flags, just in case, for later calls */
1974 LIST_FOREACH(units_by_type, u, m->units_by_type[UNIT_MOUNT])
1975 MOUNT(u)->proc_flags = 0;
1976
1977 return 0;
1978 }
1979
1980 manager_dispatch_load_queue(m);
1981
1982 LIST_FOREACH(units_by_type, u, m->units_by_type[UNIT_MOUNT]) {
1983 Mount *mount = MOUNT(u);
1984
1985 if (!mount_is_mounted(mount)) {
1986
1987 /* A mount point is not around right now. It
1988 * might be gone, or might never have
1989 * existed. */
1990
1991 if (mount->from_proc_self_mountinfo &&
1992 mount->parameters_proc_self_mountinfo.what) {
1993
1994 /* Remember that this device might just have disappeared */
1995 if (set_ensure_allocated(&gone, &path_hash_ops) < 0 ||
1996 set_put_strdup(&gone, mount->parameters_proc_self_mountinfo.what) < 0)
1997 log_oom(); /* we don't care too much about OOM here... */
1998 }
1999
2000 mount->from_proc_self_mountinfo = false;
2001 assert_se(update_parameters_proc_self_mountinfo(mount, NULL, NULL, NULL) >= 0);
2002
2003 switch (mount->state) {
2004
2005 case MOUNT_MOUNTED:
2006 /* This has just been unmounted by somebody else, follow the state change. */
2007 mount_enter_dead(mount, MOUNT_SUCCESS);
2008 break;
2009
2010 case MOUNT_MOUNTING_DONE:
2011 /* The mount command may add the corresponding proc mountinfo entry and
2012 * then remove it because of an internal error. E.g., fuse.sshfs seems
2013 * to do that when the connection fails. See #17617. To handle such the
2014 * case, let's once set the state back to mounting. Then, the unit can
2015 * correctly enter the failed state later in mount_sigchld(). */
2016 mount_set_state(mount, MOUNT_MOUNTING);
2017 break;
2018
2019 default:
2020 break;
2021 }
2022
2023 } else if (mount->proc_flags & (MOUNT_PROC_JUST_MOUNTED|MOUNT_PROC_JUST_CHANGED)) {
2024
2025 /* A mount point was added or changed */
2026
2027 switch (mount->state) {
2028
2029 case MOUNT_DEAD:
2030 case MOUNT_FAILED:
2031
2032 /* This has just been mounted by somebody else, follow the state change, but let's
2033 * generate a new invocation ID for this implicitly and automatically. */
2034 (void) unit_acquire_invocation_id(u);
2035 mount_cycle_clear(mount);
2036 mount_enter_mounted(mount, MOUNT_SUCCESS);
2037 break;
2038
2039 case MOUNT_MOUNTING:
2040 mount_set_state(mount, MOUNT_MOUNTING_DONE);
2041 break;
2042
2043 default:
2044 /* Nothing really changed, but let's
2045 * issue an notification call
2046 * nonetheless, in case somebody is
2047 * waiting for this. (e.g. file system
2048 * ro/rw remounts.) */
2049 mount_set_state(mount, mount->state);
2050 break;
2051 }
2052 }
2053
2054 if (mount_is_mounted(mount) &&
2055 mount->from_proc_self_mountinfo &&
2056 mount->parameters_proc_self_mountinfo.what) {
2057 /* Track devices currently used */
2058
2059 if (set_ensure_allocated(&around, &path_hash_ops) < 0 ||
2060 set_put_strdup(&around, mount->parameters_proc_self_mountinfo.what) < 0)
2061 log_oom();
2062 }
2063
2064 /* Reset the flags for later calls */
2065 mount->proc_flags = 0;
2066 }
2067
2068 SET_FOREACH(what, gone) {
2069 if (set_contains(around, what))
2070 continue;
2071
2072 /* Let the device units know that the device is no longer mounted */
2073 device_found_node(m, what, DEVICE_NOT_FOUND, DEVICE_FOUND_MOUNT);
2074 }
2075
2076 return 0;
2077 }
2078
mount_dispatch_io(sd_event_source * source,int fd,uint32_t revents,void * userdata)2079 static int mount_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
2080 Manager *m = userdata;
2081
2082 assert(m);
2083 assert(revents & EPOLLIN);
2084
2085 return mount_process_proc_self_mountinfo(m);
2086 }
2087
mount_reset_failed(Unit * u)2088 static void mount_reset_failed(Unit *u) {
2089 Mount *m = MOUNT(u);
2090
2091 assert(m);
2092
2093 if (m->state == MOUNT_FAILED)
2094 mount_set_state(m, MOUNT_DEAD);
2095
2096 m->result = MOUNT_SUCCESS;
2097 m->reload_result = MOUNT_SUCCESS;
2098 m->clean_result = MOUNT_SUCCESS;
2099 }
2100
mount_kill(Unit * u,KillWho who,int signo,sd_bus_error * error)2101 static int mount_kill(Unit *u, KillWho who, int signo, sd_bus_error *error) {
2102 Mount *m = MOUNT(u);
2103
2104 assert(m);
2105
2106 return unit_kill_common(u, who, signo, -1, m->control_pid, error);
2107 }
2108
mount_control_pid(Unit * u)2109 static int mount_control_pid(Unit *u) {
2110 Mount *m = MOUNT(u);
2111
2112 assert(m);
2113
2114 return m->control_pid;
2115 }
2116
mount_clean(Unit * u,ExecCleanMask mask)2117 static int mount_clean(Unit *u, ExecCleanMask mask) {
2118 _cleanup_strv_free_ char **l = NULL;
2119 Mount *m = MOUNT(u);
2120 int r;
2121
2122 assert(m);
2123 assert(mask != 0);
2124
2125 if (m->state != MOUNT_DEAD)
2126 return -EBUSY;
2127
2128 r = exec_context_get_clean_directories(&m->exec_context, u->manager->prefix, mask, &l);
2129 if (r < 0)
2130 return r;
2131
2132 if (strv_isempty(l))
2133 return -EUNATCH;
2134
2135 mount_unwatch_control_pid(m);
2136 m->clean_result = MOUNT_SUCCESS;
2137 m->control_command = NULL;
2138 m->control_command_id = _MOUNT_EXEC_COMMAND_INVALID;
2139
2140 r = mount_arm_timer(m, usec_add(now(CLOCK_MONOTONIC), m->exec_context.timeout_clean_usec));
2141 if (r < 0)
2142 goto fail;
2143
2144 r = unit_fork_and_watch_rm_rf(u, l, &m->control_pid);
2145 if (r < 0)
2146 goto fail;
2147
2148 mount_set_state(m, MOUNT_CLEANING);
2149
2150 return 0;
2151
2152 fail:
2153 log_unit_warning_errno(u, r, "Failed to initiate cleaning: %m");
2154 m->clean_result = MOUNT_FAILURE_RESOURCES;
2155 m->timer_event_source = sd_event_source_disable_unref(m->timer_event_source);
2156 return r;
2157 }
2158
mount_can_clean(Unit * u,ExecCleanMask * ret)2159 static int mount_can_clean(Unit *u, ExecCleanMask *ret) {
2160 Mount *m = MOUNT(u);
2161
2162 assert(m);
2163
2164 return exec_context_get_clean_mask(&m->exec_context, ret);
2165 }
2166
mount_can_start(Unit * u)2167 static int mount_can_start(Unit *u) {
2168 Mount *m = MOUNT(u);
2169 int r;
2170
2171 assert(m);
2172
2173 if (sd_event_source_is_ratelimited(u->manager->mount_event_source))
2174 return -EAGAIN;
2175
2176 r = unit_test_start_limit(u);
2177 if (r < 0) {
2178 mount_enter_dead(m, MOUNT_FAILURE_START_LIMIT_HIT);
2179 return r;
2180 }
2181
2182 return 1;
2183 }
2184
2185 static const char* const mount_exec_command_table[_MOUNT_EXEC_COMMAND_MAX] = {
2186 [MOUNT_EXEC_MOUNT] = "ExecMount",
2187 [MOUNT_EXEC_UNMOUNT] = "ExecUnmount",
2188 [MOUNT_EXEC_REMOUNT] = "ExecRemount",
2189 };
2190
2191 DEFINE_STRING_TABLE_LOOKUP(mount_exec_command, MountExecCommand);
2192
2193 static const char* const mount_result_table[_MOUNT_RESULT_MAX] = {
2194 [MOUNT_SUCCESS] = "success",
2195 [MOUNT_FAILURE_RESOURCES] = "resources",
2196 [MOUNT_FAILURE_TIMEOUT] = "timeout",
2197 [MOUNT_FAILURE_EXIT_CODE] = "exit-code",
2198 [MOUNT_FAILURE_SIGNAL] = "signal",
2199 [MOUNT_FAILURE_CORE_DUMP] = "core-dump",
2200 [MOUNT_FAILURE_START_LIMIT_HIT] = "start-limit-hit",
2201 [MOUNT_FAILURE_PROTOCOL] = "protocol",
2202 };
2203
2204 DEFINE_STRING_TABLE_LOOKUP(mount_result, MountResult);
2205
2206 const UnitVTable mount_vtable = {
2207 .object_size = sizeof(Mount),
2208 .exec_context_offset = offsetof(Mount, exec_context),
2209 .cgroup_context_offset = offsetof(Mount, cgroup_context),
2210 .kill_context_offset = offsetof(Mount, kill_context),
2211 .exec_runtime_offset = offsetof(Mount, exec_runtime),
2212 .dynamic_creds_offset = offsetof(Mount, dynamic_creds),
2213
2214 .sections =
2215 "Unit\0"
2216 "Mount\0"
2217 "Install\0",
2218 .private_section = "Mount",
2219
2220 .can_transient = true,
2221 .can_fail = true,
2222 .exclude_from_switch_root_serialization = true,
2223
2224 .init = mount_init,
2225 .load = mount_load,
2226 .done = mount_done,
2227
2228 .coldplug = mount_coldplug,
2229
2230 .dump = mount_dump,
2231
2232 .start = mount_start,
2233 .stop = mount_stop,
2234 .reload = mount_reload,
2235
2236 .kill = mount_kill,
2237 .clean = mount_clean,
2238 .can_clean = mount_can_clean,
2239
2240 .serialize = mount_serialize,
2241 .deserialize_item = mount_deserialize_item,
2242
2243 .active_state = mount_active_state,
2244 .sub_state_to_string = mount_sub_state_to_string,
2245
2246 .will_restart = unit_will_restart_default,
2247
2248 .may_gc = mount_may_gc,
2249 .is_extrinsic = mount_is_extrinsic,
2250
2251 .sigchld_event = mount_sigchld_event,
2252
2253 .reset_failed = mount_reset_failed,
2254
2255 .control_pid = mount_control_pid,
2256
2257 .bus_set_property = bus_mount_set_property,
2258 .bus_commit_properties = bus_mount_commit_properties,
2259
2260 .get_timeout = mount_get_timeout,
2261
2262 .enumerate_perpetual = mount_enumerate_perpetual,
2263 .enumerate = mount_enumerate,
2264 .shutdown = mount_shutdown,
2265
2266 .status_message_formats = {
2267 .starting_stopping = {
2268 [0] = "Mounting %s...",
2269 [1] = "Unmounting %s...",
2270 },
2271 .finished_start_job = {
2272 [JOB_DONE] = "Mounted %s.",
2273 [JOB_FAILED] = "Failed to mount %s.",
2274 [JOB_TIMEOUT] = "Timed out mounting %s.",
2275 },
2276 .finished_stop_job = {
2277 [JOB_DONE] = "Unmounted %s.",
2278 [JOB_FAILED] = "Failed unmounting %s.",
2279 [JOB_TIMEOUT] = "Timed out unmounting %s.",
2280 },
2281 },
2282
2283 .can_start = mount_can_start,
2284 };
2285