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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
0a268dbd TH |
2 | #include "cgroup-internal.h" |
3 | ||
1592c9b2 | 4 | #include <linux/ctype.h> |
0a268dbd TH |
5 | #include <linux/kmod.h> |
6 | #include <linux/sort.h> | |
1592c9b2 | 7 | #include <linux/delay.h> |
0a268dbd | 8 | #include <linux/mm.h> |
c3edc401 | 9 | #include <linux/sched/signal.h> |
56cd6973 | 10 | #include <linux/sched/task.h> |
50ff9d13 | 11 | #include <linux/magic.h> |
0a268dbd TH |
12 | #include <linux/slab.h> |
13 | #include <linux/vmalloc.h> | |
14 | #include <linux/delayacct.h> | |
15 | #include <linux/pid_namespace.h> | |
16 | #include <linux/cgroupstats.h> | |
8d2451f4 | 17 | #include <linux/fs_parser.h> |
0a268dbd TH |
18 | |
19 | #include <trace/events/cgroup.h> | |
20 | ||
21 | /* | |
22 | * pidlists linger the following amount before being destroyed. The goal | |
23 | * is avoiding frequent destruction in the middle of consecutive read calls | |
24 | * Expiring in the middle is a performance problem not a correctness one. | |
25 | * 1 sec should be enough. | |
26 | */ | |
27 | #define CGROUP_PIDLIST_DESTROY_DELAY HZ | |
28 | ||
29 | /* Controllers blocked by the commandline in v1 */ | |
30 | static u16 cgroup_no_v1_mask; | |
31 | ||
3fc9c12d TH |
32 | /* disable named v1 mounts */ |
33 | static bool cgroup_no_v1_named; | |
34 | ||
0a268dbd TH |
35 | /* |
36 | * pidlist destructions need to be flushed on cgroup destruction. Use a | |
37 | * separate workqueue as flush domain. | |
38 | */ | |
39 | static struct workqueue_struct *cgroup_pidlist_destroy_wq; | |
40 | ||
e7b20d97 | 41 | /* protects cgroup_subsys->release_agent_path */ |
1592c9b2 | 42 | static DEFINE_SPINLOCK(release_agent_path_lock); |
0a268dbd | 43 | |
d62beb7f | 44 | bool cgroup1_ssid_disabled(int ssid) |
0a268dbd TH |
45 | { |
46 | return cgroup_no_v1_mask & (1 << ssid); | |
47 | } | |
48 | ||
49 | /** | |
50 | * cgroup_attach_task_all - attach task 'tsk' to all cgroups of task 'from' | |
51 | * @from: attach to all cgroups of a given task | |
52 | * @tsk: the task to be attached | |
b4cc6196 RD |
53 | * |
54 | * Return: %0 on success or a negative errno code on failure | |
0a268dbd TH |
55 | */ |
56 | int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk) | |
57 | { | |
58 | struct cgroup_root *root; | |
59 | int retval = 0; | |
60 | ||
61 | mutex_lock(&cgroup_mutex); | |
62 | percpu_down_write(&cgroup_threadgroup_rwsem); | |
63 | for_each_root(root) { | |
64 | struct cgroup *from_cgrp; | |
65 | ||
0a268dbd TH |
66 | spin_lock_irq(&css_set_lock); |
67 | from_cgrp = task_cgroup_from_root(from, root); | |
68 | spin_unlock_irq(&css_set_lock); | |
69 | ||
70 | retval = cgroup_attach_task(from_cgrp, tsk, false); | |
71 | if (retval) | |
72 | break; | |
73 | } | |
74 | percpu_up_write(&cgroup_threadgroup_rwsem); | |
75 | mutex_unlock(&cgroup_mutex); | |
76 | ||
77 | return retval; | |
78 | } | |
79 | EXPORT_SYMBOL_GPL(cgroup_attach_task_all); | |
80 | ||
81 | /** | |
b4cc6196 | 82 | * cgroup_transfer_tasks - move tasks from one cgroup to another |
0a268dbd TH |
83 | * @to: cgroup to which the tasks will be moved |
84 | * @from: cgroup in which the tasks currently reside | |
85 | * | |
86 | * Locking rules between cgroup_post_fork() and the migration path | |
87 | * guarantee that, if a task is forking while being migrated, the new child | |
88 | * is guaranteed to be either visible in the source cgroup after the | |
89 | * parent's migration is complete or put into the target cgroup. No task | |
90 | * can slip out of migration through forking. | |
b4cc6196 RD |
91 | * |
92 | * Return: %0 on success or a negative errno code on failure | |
0a268dbd TH |
93 | */ |
94 | int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from) | |
95 | { | |
e595cd70 | 96 | DEFINE_CGROUP_MGCTX(mgctx); |
0a268dbd TH |
97 | struct cgrp_cset_link *link; |
98 | struct css_task_iter it; | |
99 | struct task_struct *task; | |
100 | int ret; | |
101 | ||
102 | if (cgroup_on_dfl(to)) | |
103 | return -EINVAL; | |
104 | ||
8cfd8147 TH |
105 | ret = cgroup_migrate_vet_dst(to); |
106 | if (ret) | |
107 | return ret; | |
0a268dbd TH |
108 | |
109 | mutex_lock(&cgroup_mutex); | |
110 | ||
111 | percpu_down_write(&cgroup_threadgroup_rwsem); | |
112 | ||
113 | /* all tasks in @from are being moved, all csets are source */ | |
114 | spin_lock_irq(&css_set_lock); | |
115 | list_for_each_entry(link, &from->cset_links, cset_link) | |
e595cd70 | 116 | cgroup_migrate_add_src(link->cset, to, &mgctx); |
0a268dbd TH |
117 | spin_unlock_irq(&css_set_lock); |
118 | ||
e595cd70 | 119 | ret = cgroup_migrate_prepare_dst(&mgctx); |
0a268dbd TH |
120 | if (ret) |
121 | goto out_err; | |
122 | ||
123 | /* | |
124 | * Migrate tasks one-by-one until @from is empty. This fails iff | |
125 | * ->can_attach() fails. | |
126 | */ | |
127 | do { | |
bc2fb7ed | 128 | css_task_iter_start(&from->self, 0, &it); |
116d2f74 PS |
129 | |
130 | do { | |
131 | task = css_task_iter_next(&it); | |
132 | } while (task && (task->flags & PF_EXITING)); | |
133 | ||
0a268dbd TH |
134 | if (task) |
135 | get_task_struct(task); | |
136 | css_task_iter_end(&it); | |
137 | ||
138 | if (task) { | |
bfc2cf6f | 139 | ret = cgroup_migrate(task, false, &mgctx); |
0a268dbd | 140 | if (!ret) |
e4f8d81c | 141 | TRACE_CGROUP_PATH(transfer_tasks, to, task, false); |
0a268dbd TH |
142 | put_task_struct(task); |
143 | } | |
144 | } while (task && !ret); | |
145 | out_err: | |
e595cd70 | 146 | cgroup_migrate_finish(&mgctx); |
0a268dbd TH |
147 | percpu_up_write(&cgroup_threadgroup_rwsem); |
148 | mutex_unlock(&cgroup_mutex); | |
149 | return ret; | |
150 | } | |
151 | ||
152 | /* | |
153 | * Stuff for reading the 'tasks'/'procs' files. | |
154 | * | |
155 | * Reading this file can return large amounts of data if a cgroup has | |
156 | * *lots* of attached tasks. So it may need several calls to read(), | |
157 | * but we cannot guarantee that the information we produce is correct | |
158 | * unless we produce it entirely atomically. | |
159 | * | |
160 | */ | |
161 | ||
162 | /* which pidlist file are we talking about? */ | |
163 | enum cgroup_filetype { | |
164 | CGROUP_FILE_PROCS, | |
165 | CGROUP_FILE_TASKS, | |
166 | }; | |
167 | ||
168 | /* | |
169 | * A pidlist is a list of pids that virtually represents the contents of one | |
170 | * of the cgroup files ("procs" or "tasks"). We keep a list of such pidlists, | |
171 | * a pair (one each for procs, tasks) for each pid namespace that's relevant | |
172 | * to the cgroup. | |
173 | */ | |
174 | struct cgroup_pidlist { | |
175 | /* | |
176 | * used to find which pidlist is wanted. doesn't change as long as | |
177 | * this particular list stays in the list. | |
178 | */ | |
179 | struct { enum cgroup_filetype type; struct pid_namespace *ns; } key; | |
180 | /* array of xids */ | |
181 | pid_t *list; | |
182 | /* how many elements the above list has */ | |
183 | int length; | |
184 | /* each of these stored in a list by its cgroup */ | |
185 | struct list_head links; | |
186 | /* pointer to the cgroup we belong to, for list removal purposes */ | |
187 | struct cgroup *owner; | |
188 | /* for delayed destruction */ | |
189 | struct delayed_work destroy_dwork; | |
190 | }; | |
191 | ||
0a268dbd TH |
192 | /* |
193 | * Used to destroy all pidlists lingering waiting for destroy timer. None | |
194 | * should be left afterwards. | |
195 | */ | |
d62beb7f | 196 | void cgroup1_pidlist_destroy_all(struct cgroup *cgrp) |
0a268dbd TH |
197 | { |
198 | struct cgroup_pidlist *l, *tmp_l; | |
199 | ||
200 | mutex_lock(&cgrp->pidlist_mutex); | |
201 | list_for_each_entry_safe(l, tmp_l, &cgrp->pidlists, links) | |
202 | mod_delayed_work(cgroup_pidlist_destroy_wq, &l->destroy_dwork, 0); | |
203 | mutex_unlock(&cgrp->pidlist_mutex); | |
204 | ||
205 | flush_workqueue(cgroup_pidlist_destroy_wq); | |
206 | BUG_ON(!list_empty(&cgrp->pidlists)); | |
207 | } | |
208 | ||
209 | static void cgroup_pidlist_destroy_work_fn(struct work_struct *work) | |
210 | { | |
211 | struct delayed_work *dwork = to_delayed_work(work); | |
212 | struct cgroup_pidlist *l = container_of(dwork, struct cgroup_pidlist, | |
213 | destroy_dwork); | |
214 | struct cgroup_pidlist *tofree = NULL; | |
215 | ||
216 | mutex_lock(&l->owner->pidlist_mutex); | |
217 | ||
218 | /* | |
219 | * Destroy iff we didn't get queued again. The state won't change | |
220 | * as destroy_dwork can only be queued while locked. | |
221 | */ | |
222 | if (!delayed_work_pending(dwork)) { | |
223 | list_del(&l->links); | |
653a23ca | 224 | kvfree(l->list); |
0a268dbd TH |
225 | put_pid_ns(l->key.ns); |
226 | tofree = l; | |
227 | } | |
228 | ||
229 | mutex_unlock(&l->owner->pidlist_mutex); | |
230 | kfree(tofree); | |
231 | } | |
232 | ||
233 | /* | |
234 | * pidlist_uniq - given a kmalloc()ed list, strip out all duplicate entries | |
235 | * Returns the number of unique elements. | |
236 | */ | |
237 | static int pidlist_uniq(pid_t *list, int length) | |
238 | { | |
239 | int src, dest = 1; | |
240 | ||
241 | /* | |
242 | * we presume the 0th element is unique, so i starts at 1. trivial | |
243 | * edge cases first; no work needs to be done for either | |
244 | */ | |
245 | if (length == 0 || length == 1) | |
246 | return length; | |
247 | /* src and dest walk down the list; dest counts unique elements */ | |
248 | for (src = 1; src < length; src++) { | |
249 | /* find next unique element */ | |
250 | while (list[src] == list[src-1]) { | |
251 | src++; | |
252 | if (src == length) | |
253 | goto after; | |
254 | } | |
255 | /* dest always points to where the next unique element goes */ | |
256 | list[dest] = list[src]; | |
257 | dest++; | |
258 | } | |
259 | after: | |
260 | return dest; | |
261 | } | |
262 | ||
263 | /* | |
264 | * The two pid files - task and cgroup.procs - guaranteed that the result | |
265 | * is sorted, which forced this whole pidlist fiasco. As pid order is | |
266 | * different per namespace, each namespace needs differently sorted list, | |
267 | * making it impossible to use, for example, single rbtree of member tasks | |
268 | * sorted by task pointer. As pidlists can be fairly large, allocating one | |
269 | * per open file is dangerous, so cgroup had to implement shared pool of | |
270 | * pidlists keyed by cgroup and namespace. | |
271 | */ | |
272 | static int cmppid(const void *a, const void *b) | |
273 | { | |
274 | return *(pid_t *)a - *(pid_t *)b; | |
275 | } | |
276 | ||
277 | static struct cgroup_pidlist *cgroup_pidlist_find(struct cgroup *cgrp, | |
278 | enum cgroup_filetype type) | |
279 | { | |
280 | struct cgroup_pidlist *l; | |
281 | /* don't need task_nsproxy() if we're looking at ourself */ | |
282 | struct pid_namespace *ns = task_active_pid_ns(current); | |
283 | ||
284 | lockdep_assert_held(&cgrp->pidlist_mutex); | |
285 | ||
286 | list_for_each_entry(l, &cgrp->pidlists, links) | |
287 | if (l->key.type == type && l->key.ns == ns) | |
288 | return l; | |
289 | return NULL; | |
290 | } | |
291 | ||
292 | /* | |
293 | * find the appropriate pidlist for our purpose (given procs vs tasks) | |
294 | * returns with the lock on that pidlist already held, and takes care | |
295 | * of the use count, or returns NULL with no locks held if we're out of | |
296 | * memory. | |
297 | */ | |
298 | static struct cgroup_pidlist *cgroup_pidlist_find_create(struct cgroup *cgrp, | |
299 | enum cgroup_filetype type) | |
300 | { | |
301 | struct cgroup_pidlist *l; | |
302 | ||
303 | lockdep_assert_held(&cgrp->pidlist_mutex); | |
304 | ||
305 | l = cgroup_pidlist_find(cgrp, type); | |
306 | if (l) | |
307 | return l; | |
308 | ||
309 | /* entry not found; create a new one */ | |
310 | l = kzalloc(sizeof(struct cgroup_pidlist), GFP_KERNEL); | |
311 | if (!l) | |
312 | return l; | |
313 | ||
314 | INIT_DELAYED_WORK(&l->destroy_dwork, cgroup_pidlist_destroy_work_fn); | |
315 | l->key.type = type; | |
316 | /* don't need task_nsproxy() if we're looking at ourself */ | |
317 | l->key.ns = get_pid_ns(task_active_pid_ns(current)); | |
318 | l->owner = cgrp; | |
319 | list_add(&l->links, &cgrp->pidlists); | |
320 | return l; | |
321 | } | |
322 | ||
0a268dbd TH |
323 | /* |
324 | * Load a cgroup's pidarray with either procs' tgids or tasks' pids | |
325 | */ | |
326 | static int pidlist_array_load(struct cgroup *cgrp, enum cgroup_filetype type, | |
327 | struct cgroup_pidlist **lp) | |
328 | { | |
329 | pid_t *array; | |
330 | int length; | |
331 | int pid, n = 0; /* used for populating the array */ | |
332 | struct css_task_iter it; | |
333 | struct task_struct *tsk; | |
334 | struct cgroup_pidlist *l; | |
335 | ||
336 | lockdep_assert_held(&cgrp->pidlist_mutex); | |
337 | ||
338 | /* | |
339 | * If cgroup gets more users after we read count, we won't have | |
340 | * enough space - tough. This race is indistinguishable to the | |
341 | * caller from the case that the additional cgroup users didn't | |
342 | * show up until sometime later on. | |
343 | */ | |
344 | length = cgroup_task_count(cgrp); | |
653a23ca | 345 | array = kvmalloc_array(length, sizeof(pid_t), GFP_KERNEL); |
0a268dbd TH |
346 | if (!array) |
347 | return -ENOMEM; | |
348 | /* now, populate the array */ | |
bc2fb7ed | 349 | css_task_iter_start(&cgrp->self, 0, &it); |
0a268dbd TH |
350 | while ((tsk = css_task_iter_next(&it))) { |
351 | if (unlikely(n == length)) | |
352 | break; | |
353 | /* get tgid or pid for procs or tasks file respectively */ | |
354 | if (type == CGROUP_FILE_PROCS) | |
355 | pid = task_tgid_vnr(tsk); | |
356 | else | |
357 | pid = task_pid_vnr(tsk); | |
358 | if (pid > 0) /* make sure to only use valid results */ | |
359 | array[n++] = pid; | |
360 | } | |
361 | css_task_iter_end(&it); | |
362 | length = n; | |
363 | /* now sort & (if procs) strip out duplicates */ | |
364 | sort(array, length, sizeof(pid_t), cmppid, NULL); | |
365 | if (type == CGROUP_FILE_PROCS) | |
366 | length = pidlist_uniq(array, length); | |
367 | ||
368 | l = cgroup_pidlist_find_create(cgrp, type); | |
369 | if (!l) { | |
653a23ca | 370 | kvfree(array); |
0a268dbd TH |
371 | return -ENOMEM; |
372 | } | |
373 | ||
374 | /* store array, freeing old if necessary */ | |
653a23ca | 375 | kvfree(l->list); |
0a268dbd TH |
376 | l->list = array; |
377 | l->length = length; | |
378 | *lp = l; | |
379 | return 0; | |
380 | } | |
381 | ||
382 | /* | |
383 | * seq_file methods for the tasks/procs files. The seq_file position is the | |
384 | * next pid to display; the seq_file iterator is a pointer to the pid | |
385 | * in the cgroup->l->list array. | |
386 | */ | |
387 | ||
388 | static void *cgroup_pidlist_start(struct seq_file *s, loff_t *pos) | |
389 | { | |
390 | /* | |
391 | * Initially we receive a position value that corresponds to | |
392 | * one more than the last pid shown (or 0 on the first call or | |
393 | * after a seek to the start). Use a binary-search to find the | |
394 | * next pid to display, if any | |
395 | */ | |
396 | struct kernfs_open_file *of = s->private; | |
397 | struct cgroup *cgrp = seq_css(s)->cgroup; | |
398 | struct cgroup_pidlist *l; | |
399 | enum cgroup_filetype type = seq_cft(s)->private; | |
400 | int index = 0, pid = *pos; | |
401 | int *iter, ret; | |
402 | ||
403 | mutex_lock(&cgrp->pidlist_mutex); | |
404 | ||
405 | /* | |
406 | * !NULL @of->priv indicates that this isn't the first start() | |
407 | * after open. If the matching pidlist is around, we can use that. | |
408 | * Look for it. Note that @of->priv can't be used directly. It | |
409 | * could already have been destroyed. | |
410 | */ | |
411 | if (of->priv) | |
412 | of->priv = cgroup_pidlist_find(cgrp, type); | |
413 | ||
414 | /* | |
415 | * Either this is the first start() after open or the matching | |
416 | * pidlist has been destroyed inbetween. Create a new one. | |
417 | */ | |
418 | if (!of->priv) { | |
419 | ret = pidlist_array_load(cgrp, type, | |
420 | (struct cgroup_pidlist **)&of->priv); | |
421 | if (ret) | |
422 | return ERR_PTR(ret); | |
423 | } | |
424 | l = of->priv; | |
425 | ||
426 | if (pid) { | |
427 | int end = l->length; | |
428 | ||
429 | while (index < end) { | |
430 | int mid = (index + end) / 2; | |
431 | if (l->list[mid] == pid) { | |
432 | index = mid; | |
433 | break; | |
434 | } else if (l->list[mid] <= pid) | |
435 | index = mid + 1; | |
436 | else | |
437 | end = mid; | |
438 | } | |
439 | } | |
440 | /* If we're off the end of the array, we're done */ | |
441 | if (index >= l->length) | |
442 | return NULL; | |
443 | /* Update the abstract position to be the actual pid that we found */ | |
444 | iter = l->list + index; | |
445 | *pos = *iter; | |
446 | return iter; | |
447 | } | |
448 | ||
449 | static void cgroup_pidlist_stop(struct seq_file *s, void *v) | |
450 | { | |
451 | struct kernfs_open_file *of = s->private; | |
452 | struct cgroup_pidlist *l = of->priv; | |
453 | ||
454 | if (l) | |
455 | mod_delayed_work(cgroup_pidlist_destroy_wq, &l->destroy_dwork, | |
456 | CGROUP_PIDLIST_DESTROY_DELAY); | |
457 | mutex_unlock(&seq_css(s)->cgroup->pidlist_mutex); | |
458 | } | |
459 | ||
460 | static void *cgroup_pidlist_next(struct seq_file *s, void *v, loff_t *pos) | |
461 | { | |
462 | struct kernfs_open_file *of = s->private; | |
463 | struct cgroup_pidlist *l = of->priv; | |
464 | pid_t *p = v; | |
465 | pid_t *end = l->list + l->length; | |
466 | /* | |
467 | * Advance to the next pid in the array. If this goes off the | |
468 | * end, we're done | |
469 | */ | |
470 | p++; | |
471 | if (p >= end) { | |
db8dd969 | 472 | (*pos)++; |
0a268dbd TH |
473 | return NULL; |
474 | } else { | |
475 | *pos = *p; | |
476 | return p; | |
477 | } | |
478 | } | |
479 | ||
480 | static int cgroup_pidlist_show(struct seq_file *s, void *v) | |
481 | { | |
482 | seq_printf(s, "%d\n", *(int *)v); | |
483 | ||
484 | return 0; | |
485 | } | |
486 | ||
715c809d TH |
487 | static ssize_t __cgroup1_procs_write(struct kernfs_open_file *of, |
488 | char *buf, size_t nbytes, loff_t off, | |
489 | bool threadgroup) | |
0a268dbd | 490 | { |
715c809d TH |
491 | struct cgroup *cgrp; |
492 | struct task_struct *task; | |
493 | const struct cred *cred, *tcred; | |
494 | ssize_t ret; | |
9a3284fa | 495 | bool locked; |
715c809d TH |
496 | |
497 | cgrp = cgroup_kn_lock_live(of->kn, false); | |
498 | if (!cgrp) | |
499 | return -ENODEV; | |
500 | ||
9a3284fa | 501 | task = cgroup_procs_write_start(buf, threadgroup, &locked); |
715c809d TH |
502 | ret = PTR_ERR_OR_ZERO(task); |
503 | if (ret) | |
504 | goto out_unlock; | |
505 | ||
506 | /* | |
507 | * Even if we're attaching all tasks in the thread group, we only | |
508 | * need to check permissions on one of them. | |
509 | */ | |
510 | cred = current_cred(); | |
511 | tcred = get_task_cred(task); | |
512 | if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) && | |
513 | !uid_eq(cred->euid, tcred->uid) && | |
514 | !uid_eq(cred->euid, tcred->suid)) | |
515 | ret = -EACCES; | |
516 | put_cred(tcred); | |
517 | if (ret) | |
518 | goto out_finish; | |
519 | ||
520 | ret = cgroup_attach_task(cgrp, task, threadgroup); | |
521 | ||
522 | out_finish: | |
9a3284fa | 523 | cgroup_procs_write_finish(task, locked); |
715c809d TH |
524 | out_unlock: |
525 | cgroup_kn_unlock(of->kn); | |
526 | ||
527 | return ret ?: nbytes; | |
528 | } | |
529 | ||
530 | static ssize_t cgroup1_procs_write(struct kernfs_open_file *of, | |
531 | char *buf, size_t nbytes, loff_t off) | |
532 | { | |
533 | return __cgroup1_procs_write(of, buf, nbytes, off, true); | |
534 | } | |
535 | ||
536 | static ssize_t cgroup1_tasks_write(struct kernfs_open_file *of, | |
537 | char *buf, size_t nbytes, loff_t off) | |
538 | { | |
539 | return __cgroup1_procs_write(of, buf, nbytes, off, false); | |
0a268dbd TH |
540 | } |
541 | ||
542 | static ssize_t cgroup_release_agent_write(struct kernfs_open_file *of, | |
543 | char *buf, size_t nbytes, loff_t off) | |
544 | { | |
545 | struct cgroup *cgrp; | |
546 | ||
547 | BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX); | |
548 | ||
549 | cgrp = cgroup_kn_lock_live(of->kn, false); | |
550 | if (!cgrp) | |
551 | return -ENODEV; | |
552 | spin_lock(&release_agent_path_lock); | |
553 | strlcpy(cgrp->root->release_agent_path, strstrip(buf), | |
554 | sizeof(cgrp->root->release_agent_path)); | |
555 | spin_unlock(&release_agent_path_lock); | |
556 | cgroup_kn_unlock(of->kn); | |
557 | return nbytes; | |
558 | } | |
559 | ||
560 | static int cgroup_release_agent_show(struct seq_file *seq, void *v) | |
561 | { | |
562 | struct cgroup *cgrp = seq_css(seq)->cgroup; | |
563 | ||
564 | spin_lock(&release_agent_path_lock); | |
565 | seq_puts(seq, cgrp->root->release_agent_path); | |
566 | spin_unlock(&release_agent_path_lock); | |
567 | seq_putc(seq, '\n'); | |
568 | return 0; | |
569 | } | |
570 | ||
571 | static int cgroup_sane_behavior_show(struct seq_file *seq, void *v) | |
572 | { | |
573 | seq_puts(seq, "0\n"); | |
574 | return 0; | |
575 | } | |
576 | ||
577 | static u64 cgroup_read_notify_on_release(struct cgroup_subsys_state *css, | |
578 | struct cftype *cft) | |
579 | { | |
580 | return notify_on_release(css->cgroup); | |
581 | } | |
582 | ||
583 | static int cgroup_write_notify_on_release(struct cgroup_subsys_state *css, | |
584 | struct cftype *cft, u64 val) | |
585 | { | |
586 | if (val) | |
587 | set_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags); | |
588 | else | |
589 | clear_bit(CGRP_NOTIFY_ON_RELEASE, &css->cgroup->flags); | |
590 | return 0; | |
591 | } | |
592 | ||
593 | static u64 cgroup_clone_children_read(struct cgroup_subsys_state *css, | |
594 | struct cftype *cft) | |
595 | { | |
596 | return test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags); | |
597 | } | |
598 | ||
599 | static int cgroup_clone_children_write(struct cgroup_subsys_state *css, | |
600 | struct cftype *cft, u64 val) | |
601 | { | |
602 | if (val) | |
603 | set_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags); | |
604 | else | |
605 | clear_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags); | |
606 | return 0; | |
607 | } | |
608 | ||
609 | /* cgroup core interface files for the legacy hierarchies */ | |
d62beb7f | 610 | struct cftype cgroup1_base_files[] = { |
0a268dbd TH |
611 | { |
612 | .name = "cgroup.procs", | |
613 | .seq_start = cgroup_pidlist_start, | |
614 | .seq_next = cgroup_pidlist_next, | |
615 | .seq_stop = cgroup_pidlist_stop, | |
616 | .seq_show = cgroup_pidlist_show, | |
617 | .private = CGROUP_FILE_PROCS, | |
715c809d | 618 | .write = cgroup1_procs_write, |
0a268dbd TH |
619 | }, |
620 | { | |
621 | .name = "cgroup.clone_children", | |
622 | .read_u64 = cgroup_clone_children_read, | |
623 | .write_u64 = cgroup_clone_children_write, | |
624 | }, | |
625 | { | |
626 | .name = "cgroup.sane_behavior", | |
627 | .flags = CFTYPE_ONLY_ON_ROOT, | |
628 | .seq_show = cgroup_sane_behavior_show, | |
629 | }, | |
630 | { | |
631 | .name = "tasks", | |
632 | .seq_start = cgroup_pidlist_start, | |
633 | .seq_next = cgroup_pidlist_next, | |
634 | .seq_stop = cgroup_pidlist_stop, | |
635 | .seq_show = cgroup_pidlist_show, | |
636 | .private = CGROUP_FILE_TASKS, | |
715c809d | 637 | .write = cgroup1_tasks_write, |
0a268dbd TH |
638 | }, |
639 | { | |
640 | .name = "notify_on_release", | |
641 | .read_u64 = cgroup_read_notify_on_release, | |
642 | .write_u64 = cgroup_write_notify_on_release, | |
643 | }, | |
644 | { | |
645 | .name = "release_agent", | |
646 | .flags = CFTYPE_ONLY_ON_ROOT, | |
647 | .seq_show = cgroup_release_agent_show, | |
648 | .write = cgroup_release_agent_write, | |
649 | .max_write_len = PATH_MAX - 1, | |
650 | }, | |
651 | { } /* terminate */ | |
652 | }; | |
653 | ||
654 | /* Display information about each subsystem and each hierarchy */ | |
3f3942ac | 655 | int proc_cgroupstats_show(struct seq_file *m, void *v) |
0a268dbd TH |
656 | { |
657 | struct cgroup_subsys *ss; | |
658 | int i; | |
659 | ||
660 | seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\tenabled\n"); | |
661 | /* | |
822bc9ba SB |
662 | * Grab the subsystems state racily. No need to add avenue to |
663 | * cgroup_mutex contention. | |
0a268dbd | 664 | */ |
0a268dbd TH |
665 | |
666 | for_each_subsys(ss, i) | |
667 | seq_printf(m, "%s\t%d\t%d\t%d\n", | |
668 | ss->legacy_name, ss->root->hierarchy_id, | |
669 | atomic_read(&ss->root->nr_cgrps), | |
670 | cgroup_ssid_enabled(i)); | |
671 | ||
0a268dbd TH |
672 | return 0; |
673 | } | |
674 | ||
0a268dbd TH |
675 | /** |
676 | * cgroupstats_build - build and fill cgroupstats | |
677 | * @stats: cgroupstats to fill information into | |
678 | * @dentry: A dentry entry belonging to the cgroup for which stats have | |
679 | * been requested. | |
680 | * | |
681 | * Build and fill cgroupstats so that taskstats can export it to user | |
682 | * space. | |
b4cc6196 RD |
683 | * |
684 | * Return: %0 on success or a negative errno code on failure | |
0a268dbd TH |
685 | */ |
686 | int cgroupstats_build(struct cgroupstats *stats, struct dentry *dentry) | |
687 | { | |
688 | struct kernfs_node *kn = kernfs_node_from_dentry(dentry); | |
689 | struct cgroup *cgrp; | |
690 | struct css_task_iter it; | |
691 | struct task_struct *tsk; | |
692 | ||
693 | /* it should be kernfs_node belonging to cgroupfs and is a directory */ | |
694 | if (dentry->d_sb->s_type != &cgroup_fs_type || !kn || | |
695 | kernfs_type(kn) != KERNFS_DIR) | |
696 | return -EINVAL; | |
697 | ||
0a268dbd TH |
698 | /* |
699 | * We aren't being called from kernfs and there's no guarantee on | |
700 | * @kn->priv's validity. For this and css_tryget_online_from_dir(), | |
701 | * @kn->priv is RCU safe. Let's do the RCU dancing. | |
702 | */ | |
703 | rcu_read_lock(); | |
e0aed7c7 | 704 | cgrp = rcu_dereference(*(void __rcu __force **)&kn->priv); |
bb758421 | 705 | if (!cgrp || !cgroup_tryget(cgrp)) { |
0a268dbd | 706 | rcu_read_unlock(); |
0a268dbd TH |
707 | return -ENOENT; |
708 | } | |
709 | rcu_read_unlock(); | |
710 | ||
bc2fb7ed | 711 | css_task_iter_start(&cgrp->self, 0, &it); |
0a268dbd | 712 | while ((tsk = css_task_iter_next(&it))) { |
2f064a59 | 713 | switch (READ_ONCE(tsk->__state)) { |
0a268dbd TH |
714 | case TASK_RUNNING: |
715 | stats->nr_running++; | |
716 | break; | |
717 | case TASK_INTERRUPTIBLE: | |
718 | stats->nr_sleeping++; | |
719 | break; | |
720 | case TASK_UNINTERRUPTIBLE: | |
721 | stats->nr_uninterruptible++; | |
722 | break; | |
723 | case TASK_STOPPED: | |
724 | stats->nr_stopped++; | |
725 | break; | |
726 | default: | |
ffeee417 | 727 | if (tsk->in_iowait) |
0a268dbd TH |
728 | stats->nr_io_wait++; |
729 | break; | |
730 | } | |
731 | } | |
732 | css_task_iter_end(&it); | |
733 | ||
bb758421 | 734 | cgroup_put(cgrp); |
0a268dbd TH |
735 | return 0; |
736 | } | |
737 | ||
d62beb7f | 738 | void cgroup1_check_for_release(struct cgroup *cgrp) |
0a268dbd TH |
739 | { |
740 | if (notify_on_release(cgrp) && !cgroup_is_populated(cgrp) && | |
741 | !css_has_online_children(&cgrp->self) && !cgroup_is_dead(cgrp)) | |
742 | schedule_work(&cgrp->release_agent_work); | |
743 | } | |
744 | ||
745 | /* | |
746 | * Notify userspace when a cgroup is released, by running the | |
747 | * configured release agent with the name of the cgroup (path | |
748 | * relative to the root of cgroup file system) as the argument. | |
749 | * | |
750 | * Most likely, this user command will try to rmdir this cgroup. | |
751 | * | |
752 | * This races with the possibility that some other task will be | |
753 | * attached to this cgroup before it is removed, or that some other | |
754 | * user task will 'mkdir' a child cgroup of this cgroup. That's ok. | |
755 | * The presumed 'rmdir' will fail quietly if this cgroup is no longer | |
756 | * unused, and this cgroup will be reprieved from its death sentence, | |
757 | * to continue to serve a useful existence. Next time it's released, | |
758 | * we will get notified again, if it still has 'notify_on_release' set. | |
759 | * | |
760 | * The final arg to call_usermodehelper() is UMH_WAIT_EXEC, which | |
761 | * means only wait until the task is successfully execve()'d. The | |
762 | * separate release agent task is forked by call_usermodehelper(), | |
763 | * then control in this thread returns here, without waiting for the | |
764 | * release agent task. We don't bother to wait because the caller of | |
765 | * this routine has no use for the exit status of the release agent | |
766 | * task, so no sense holding our caller up for that. | |
767 | */ | |
d62beb7f | 768 | void cgroup1_release_agent(struct work_struct *work) |
0a268dbd TH |
769 | { |
770 | struct cgroup *cgrp = | |
771 | container_of(work, struct cgroup, release_agent_work); | |
e7b20d97 | 772 | char *pathbuf, *agentbuf; |
0a268dbd TH |
773 | char *argv[3], *envp[3]; |
774 | int ret; | |
775 | ||
e7b20d97 TH |
776 | /* snoop agent path and exit early if empty */ |
777 | if (!cgrp->root->release_agent_path[0]) | |
778 | return; | |
0a268dbd | 779 | |
e7b20d97 | 780 | /* prepare argument buffers */ |
0a268dbd | 781 | pathbuf = kmalloc(PATH_MAX, GFP_KERNEL); |
e7b20d97 TH |
782 | agentbuf = kmalloc(PATH_MAX, GFP_KERNEL); |
783 | if (!pathbuf || !agentbuf) | |
784 | goto out_free; | |
0a268dbd | 785 | |
e7b20d97 TH |
786 | spin_lock(&release_agent_path_lock); |
787 | strlcpy(agentbuf, cgrp->root->release_agent_path, PATH_MAX); | |
788 | spin_unlock(&release_agent_path_lock); | |
789 | if (!agentbuf[0]) | |
790 | goto out_free; | |
791 | ||
792 | ret = cgroup_path_ns(cgrp, pathbuf, PATH_MAX, &init_cgroup_ns); | |
0a268dbd | 793 | if (ret < 0 || ret >= PATH_MAX) |
e7b20d97 | 794 | goto out_free; |
0a268dbd TH |
795 | |
796 | argv[0] = agentbuf; | |
797 | argv[1] = pathbuf; | |
798 | argv[2] = NULL; | |
799 | ||
800 | /* minimal command environment */ | |
801 | envp[0] = "HOME=/"; | |
802 | envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin"; | |
803 | envp[2] = NULL; | |
804 | ||
0a268dbd | 805 | call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC); |
0a268dbd TH |
806 | out_free: |
807 | kfree(agentbuf); | |
808 | kfree(pathbuf); | |
809 | } | |
810 | ||
811 | /* | |
812 | * cgroup_rename - Only allow simple rename of directories in place. | |
813 | */ | |
1592c9b2 TH |
814 | static int cgroup1_rename(struct kernfs_node *kn, struct kernfs_node *new_parent, |
815 | const char *new_name_str) | |
0a268dbd TH |
816 | { |
817 | struct cgroup *cgrp = kn->priv; | |
818 | int ret; | |
819 | ||
b7e24eb1 AK |
820 | /* do not accept '\n' to prevent making /proc/<pid>/cgroup unparsable */ |
821 | if (strchr(new_name_str, '\n')) | |
822 | return -EINVAL; | |
823 | ||
0a268dbd TH |
824 | if (kernfs_type(kn) != KERNFS_DIR) |
825 | return -ENOTDIR; | |
826 | if (kn->parent != new_parent) | |
827 | return -EIO; | |
828 | ||
0a268dbd TH |
829 | /* |
830 | * We're gonna grab cgroup_mutex which nests outside kernfs | |
831 | * active_ref. kernfs_rename() doesn't require active_ref | |
832 | * protection. Break them before grabbing cgroup_mutex. | |
833 | */ | |
834 | kernfs_break_active_protection(new_parent); | |
835 | kernfs_break_active_protection(kn); | |
836 | ||
837 | mutex_lock(&cgroup_mutex); | |
838 | ||
839 | ret = kernfs_rename(kn, new_parent, new_name_str); | |
840 | if (!ret) | |
e4f8d81c | 841 | TRACE_CGROUP_PATH(rename, cgrp); |
0a268dbd TH |
842 | |
843 | mutex_unlock(&cgroup_mutex); | |
844 | ||
845 | kernfs_unbreak_active_protection(kn); | |
846 | kernfs_unbreak_active_protection(new_parent); | |
847 | return ret; | |
848 | } | |
849 | ||
1592c9b2 TH |
850 | static int cgroup1_show_options(struct seq_file *seq, struct kernfs_root *kf_root) |
851 | { | |
852 | struct cgroup_root *root = cgroup_root_from_kf(kf_root); | |
853 | struct cgroup_subsys *ss; | |
854 | int ssid; | |
855 | ||
856 | for_each_subsys(ss, ssid) | |
857 | if (root->subsys_mask & (1 << ssid)) | |
858 | seq_show_option(seq, ss->legacy_name, NULL); | |
859 | if (root->flags & CGRP_ROOT_NOPREFIX) | |
860 | seq_puts(seq, ",noprefix"); | |
861 | if (root->flags & CGRP_ROOT_XATTR) | |
862 | seq_puts(seq, ",xattr"); | |
e1cba4b8 WL |
863 | if (root->flags & CGRP_ROOT_CPUSET_V2_MODE) |
864 | seq_puts(seq, ",cpuset_v2_mode"); | |
1592c9b2 TH |
865 | |
866 | spin_lock(&release_agent_path_lock); | |
867 | if (strlen(root->release_agent_path)) | |
868 | seq_show_option(seq, "release_agent", | |
869 | root->release_agent_path); | |
870 | spin_unlock(&release_agent_path_lock); | |
871 | ||
872 | if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags)) | |
873 | seq_puts(seq, ",clone_children"); | |
874 | if (strlen(root->name)) | |
875 | seq_show_option(seq, "name", root->name); | |
876 | return 0; | |
877 | } | |
878 | ||
8d2451f4 AV |
879 | enum cgroup1_param { |
880 | Opt_all, | |
881 | Opt_clone_children, | |
882 | Opt_cpuset_v2_mode, | |
883 | Opt_name, | |
884 | Opt_none, | |
885 | Opt_noprefix, | |
886 | Opt_release_agent, | |
887 | Opt_xattr, | |
888 | }; | |
1592c9b2 | 889 | |
d7167b14 | 890 | const struct fs_parameter_spec cgroup1_fs_parameters[] = { |
8d2451f4 AV |
891 | fsparam_flag ("all", Opt_all), |
892 | fsparam_flag ("clone_children", Opt_clone_children), | |
893 | fsparam_flag ("cpuset_v2_mode", Opt_cpuset_v2_mode), | |
894 | fsparam_string("name", Opt_name), | |
895 | fsparam_flag ("none", Opt_none), | |
896 | fsparam_flag ("noprefix", Opt_noprefix), | |
897 | fsparam_string("release_agent", Opt_release_agent), | |
898 | fsparam_flag ("xattr", Opt_xattr), | |
899 | {} | |
900 | }; | |
1592c9b2 | 901 | |
8d2451f4 AV |
902 | int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param) |
903 | { | |
904 | struct cgroup_fs_context *ctx = cgroup_fc2context(fc); | |
905 | struct cgroup_subsys *ss; | |
906 | struct fs_parse_result result; | |
907 | int opt, i; | |
908 | ||
d7167b14 | 909 | opt = fs_parse(fc, cgroup1_fs_parameters, param, &result); |
8d2451f4 | 910 | if (opt == -ENOPARAM) { |
d1d488d8 CB |
911 | int ret; |
912 | ||
913 | ret = vfs_parse_fs_param_source(fc, param); | |
914 | if (ret != -ENOPARAM) | |
915 | return ret; | |
1592c9b2 | 916 | for_each_subsys(ss, i) { |
8d2451f4 | 917 | if (strcmp(param->key, ss->legacy_name)) |
1592c9b2 | 918 | continue; |
61e960b0 CZ |
919 | if (!cgroup_ssid_enabled(i) || cgroup1_ssid_disabled(i)) |
920 | return invalfc(fc, "Disabled controller '%s'", | |
921 | param->key); | |
f5dfb531 | 922 | ctx->subsys_mask |= (1 << i); |
8d2451f4 | 923 | return 0; |
1592c9b2 | 924 | } |
58c025f0 | 925 | return invalfc(fc, "Unknown subsys name '%s'", param->key); |
8d2451f4 AV |
926 | } |
927 | if (opt < 0) | |
928 | return opt; | |
929 | ||
930 | switch (opt) { | |
931 | case Opt_none: | |
932 | /* Explicitly have no subsystems */ | |
933 | ctx->none = true; | |
934 | break; | |
935 | case Opt_all: | |
936 | ctx->all_ss = true; | |
937 | break; | |
938 | case Opt_noprefix: | |
939 | ctx->flags |= CGRP_ROOT_NOPREFIX; | |
940 | break; | |
941 | case Opt_clone_children: | |
942 | ctx->cpuset_clone_children = true; | |
943 | break; | |
944 | case Opt_cpuset_v2_mode: | |
945 | ctx->flags |= CGRP_ROOT_CPUSET_V2_MODE; | |
946 | break; | |
947 | case Opt_xattr: | |
948 | ctx->flags |= CGRP_ROOT_XATTR; | |
949 | break; | |
950 | case Opt_release_agent: | |
951 | /* Specifying two release agents is forbidden */ | |
952 | if (ctx->release_agent) | |
58c025f0 | 953 | return invalfc(fc, "release_agent respecified"); |
8d2451f4 AV |
954 | ctx->release_agent = param->string; |
955 | param->string = NULL; | |
956 | break; | |
957 | case Opt_name: | |
958 | /* blocked by boot param? */ | |
959 | if (cgroup_no_v1_named) | |
1592c9b2 | 960 | return -ENOENT; |
8d2451f4 AV |
961 | /* Can't specify an empty name */ |
962 | if (!param->size) | |
58c025f0 | 963 | return invalfc(fc, "Empty name"); |
8d2451f4 | 964 | if (param->size > MAX_CGROUP_ROOT_NAMELEN - 1) |
58c025f0 | 965 | return invalfc(fc, "Name too long"); |
8d2451f4 AV |
966 | /* Must match [\w.-]+ */ |
967 | for (i = 0; i < param->size; i++) { | |
968 | char c = param->string[i]; | |
969 | if (isalnum(c)) | |
970 | continue; | |
971 | if ((c == '.') || (c == '-') || (c == '_')) | |
972 | continue; | |
58c025f0 | 973 | return invalfc(fc, "Invalid name"); |
8d2451f4 AV |
974 | } |
975 | /* Specifying two names is forbidden */ | |
976 | if (ctx->name) | |
58c025f0 | 977 | return invalfc(fc, "name respecified"); |
8d2451f4 AV |
978 | ctx->name = param->string; |
979 | param->string = NULL; | |
980 | break; | |
1592c9b2 | 981 | } |
f5dfb531 AV |
982 | return 0; |
983 | } | |
984 | ||
8d2451f4 | 985 | static int check_cgroupfs_options(struct fs_context *fc) |
f5dfb531 | 986 | { |
8d2451f4 | 987 | struct cgroup_fs_context *ctx = cgroup_fc2context(fc); |
f5dfb531 AV |
988 | u16 mask = U16_MAX; |
989 | u16 enabled = 0; | |
990 | struct cgroup_subsys *ss; | |
991 | int i; | |
992 | ||
993 | #ifdef CONFIG_CPUSETS | |
994 | mask = ~((u16)1 << cpuset_cgrp_id); | |
995 | #endif | |
996 | for_each_subsys(ss, i) | |
997 | if (cgroup_ssid_enabled(i) && !cgroup1_ssid_disabled(i)) | |
998 | enabled |= 1 << i; | |
999 | ||
1000 | ctx->subsys_mask &= enabled; | |
1592c9b2 TH |
1001 | |
1002 | /* | |
08b2b6fd | 1003 | * In absence of 'none', 'name=' and subsystem name options, |
f5dfb531 | 1004 | * let's default to 'all'. |
1592c9b2 | 1005 | */ |
f5dfb531 AV |
1006 | if (!ctx->subsys_mask && !ctx->none && !ctx->name) |
1007 | ctx->all_ss = true; | |
1008 | ||
1009 | if (ctx->all_ss) { | |
1010 | /* Mutually exclusive option 'all' + subsystem name */ | |
1011 | if (ctx->subsys_mask) | |
58c025f0 | 1012 | return invalfc(fc, "subsys name conflicts with all"); |
f5dfb531 AV |
1013 | /* 'all' => select all the subsystems */ |
1014 | ctx->subsys_mask = enabled; | |
1015 | } | |
1592c9b2 TH |
1016 | |
1017 | /* | |
1018 | * We either have to specify by name or by subsystems. (So all | |
1019 | * empty hierarchies must have a name). | |
1020 | */ | |
f5dfb531 | 1021 | if (!ctx->subsys_mask && !ctx->name) |
58c025f0 | 1022 | return invalfc(fc, "Need name or subsystem set"); |
1592c9b2 TH |
1023 | |
1024 | /* | |
1025 | * Option noprefix was introduced just for backward compatibility | |
1026 | * with the old cpuset, so we allow noprefix only if mounting just | |
1027 | * the cpuset subsystem. | |
1028 | */ | |
f5dfb531 | 1029 | if ((ctx->flags & CGRP_ROOT_NOPREFIX) && (ctx->subsys_mask & mask)) |
58c025f0 | 1030 | return invalfc(fc, "noprefix used incorrectly"); |
1592c9b2 TH |
1031 | |
1032 | /* Can't specify "none" and some subsystems */ | |
f5dfb531 | 1033 | if (ctx->subsys_mask && ctx->none) |
58c025f0 | 1034 | return invalfc(fc, "none used incorrectly"); |
1592c9b2 TH |
1035 | |
1036 | return 0; | |
1037 | } | |
1038 | ||
90129625 | 1039 | int cgroup1_reconfigure(struct fs_context *fc) |
1592c9b2 | 1040 | { |
90129625 AV |
1041 | struct cgroup_fs_context *ctx = cgroup_fc2context(fc); |
1042 | struct kernfs_root *kf_root = kernfs_root_from_sb(fc->root->d_sb); | |
1592c9b2 | 1043 | struct cgroup_root *root = cgroup_root_from_kf(kf_root); |
90129625 | 1044 | int ret = 0; |
1592c9b2 TH |
1045 | u16 added_mask, removed_mask; |
1046 | ||
1047 | cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp); | |
1048 | ||
1049 | /* See what subsystems are wanted */ | |
8d2451f4 | 1050 | ret = check_cgroupfs_options(fc); |
1592c9b2 TH |
1051 | if (ret) |
1052 | goto out_unlock; | |
1053 | ||
f5dfb531 | 1054 | if (ctx->subsys_mask != root->subsys_mask || ctx->release_agent) |
1592c9b2 TH |
1055 | pr_warn("option changes via remount are deprecated (pid=%d comm=%s)\n", |
1056 | task_tgid_nr(current), current->comm); | |
1057 | ||
f5dfb531 AV |
1058 | added_mask = ctx->subsys_mask & ~root->subsys_mask; |
1059 | removed_mask = root->subsys_mask & ~ctx->subsys_mask; | |
1592c9b2 TH |
1060 | |
1061 | /* Don't allow flags or name to change at remount */ | |
f5dfb531 AV |
1062 | if ((ctx->flags ^ root->flags) || |
1063 | (ctx->name && strcmp(ctx->name, root->name))) { | |
58c025f0 | 1064 | errorfc(fc, "option or name mismatch, new: 0x%x \"%s\", old: 0x%x \"%s\"", |
f5dfb531 | 1065 | ctx->flags, ctx->name ?: "", root->flags, root->name); |
1592c9b2 TH |
1066 | ret = -EINVAL; |
1067 | goto out_unlock; | |
1068 | } | |
1069 | ||
1070 | /* remounting is not allowed for populated hierarchies */ | |
1071 | if (!list_empty(&root->cgrp.self.children)) { | |
1072 | ret = -EBUSY; | |
1073 | goto out_unlock; | |
1074 | } | |
1075 | ||
1076 | ret = rebind_subsystems(root, added_mask); | |
1077 | if (ret) | |
1078 | goto out_unlock; | |
1079 | ||
1080 | WARN_ON(rebind_subsystems(&cgrp_dfl_root, removed_mask)); | |
1081 | ||
f5dfb531 | 1082 | if (ctx->release_agent) { |
1592c9b2 | 1083 | spin_lock(&release_agent_path_lock); |
f5dfb531 | 1084 | strcpy(root->release_agent_path, ctx->release_agent); |
1592c9b2 TH |
1085 | spin_unlock(&release_agent_path_lock); |
1086 | } | |
1087 | ||
1088 | trace_cgroup_remount(root); | |
1089 | ||
1090 | out_unlock: | |
1592c9b2 TH |
1091 | mutex_unlock(&cgroup_mutex); |
1092 | return ret; | |
1093 | } | |
1094 | ||
1095 | struct kernfs_syscall_ops cgroup1_kf_syscall_ops = { | |
1096 | .rename = cgroup1_rename, | |
1097 | .show_options = cgroup1_show_options, | |
1592c9b2 TH |
1098 | .mkdir = cgroup_mkdir, |
1099 | .rmdir = cgroup_rmdir, | |
1100 | .show_path = cgroup_show_path, | |
1101 | }; | |
1102 | ||
6678889f AV |
1103 | /* |
1104 | * The guts of cgroup1 mount - find or create cgroup_root to use. | |
1105 | * Called with cgroup_mutex held; returns 0 on success, -E... on | |
1106 | * error and positive - in case when the candidate is busy dying. | |
1107 | * On success it stashes a reference to cgroup_root into given | |
1108 | * cgroup_fs_context; that reference is *NOT* counting towards the | |
1109 | * cgroup_root refcount. | |
1110 | */ | |
1111 | static int cgroup1_root_to_use(struct fs_context *fc) | |
1592c9b2 | 1112 | { |
7feeef58 | 1113 | struct cgroup_fs_context *ctx = cgroup_fc2context(fc); |
1592c9b2 TH |
1114 | struct cgroup_root *root; |
1115 | struct cgroup_subsys *ss; | |
1592c9b2 TH |
1116 | int i, ret; |
1117 | ||
1592c9b2 | 1118 | /* First find the desired set of subsystems */ |
8d2451f4 | 1119 | ret = check_cgroupfs_options(fc); |
1592c9b2 | 1120 | if (ret) |
6678889f | 1121 | return ret; |
1592c9b2 TH |
1122 | |
1123 | /* | |
1124 | * Destruction of cgroup root is asynchronous, so subsystems may | |
1125 | * still be dying after the previous unmount. Let's drain the | |
1126 | * dying subsystems. We just need to ensure that the ones | |
1127 | * unmounted previously finish dying and don't care about new ones | |
1128 | * starting. Testing ref liveliness is good enough. | |
1129 | */ | |
1130 | for_each_subsys(ss, i) { | |
f5dfb531 | 1131 | if (!(ctx->subsys_mask & (1 << i)) || |
1592c9b2 TH |
1132 | ss->root == &cgrp_dfl_root) |
1133 | continue; | |
1134 | ||
6678889f AV |
1135 | if (!percpu_ref_tryget_live(&ss->root->cgrp.self.refcnt)) |
1136 | return 1; /* restart */ | |
1592c9b2 TH |
1137 | cgroup_put(&ss->root->cgrp); |
1138 | } | |
1139 | ||
1140 | for_each_root(root) { | |
1141 | bool name_match = false; | |
1142 | ||
1143 | if (root == &cgrp_dfl_root) | |
1144 | continue; | |
1145 | ||
1146 | /* | |
1147 | * If we asked for a name then it must match. Also, if | |
1148 | * name matches but sybsys_mask doesn't, we should fail. | |
1149 | * Remember whether name matched. | |
1150 | */ | |
f5dfb531 AV |
1151 | if (ctx->name) { |
1152 | if (strcmp(ctx->name, root->name)) | |
1592c9b2 TH |
1153 | continue; |
1154 | name_match = true; | |
1155 | } | |
1156 | ||
1157 | /* | |
1158 | * If we asked for subsystems (or explicitly for no | |
1159 | * subsystems) then they must match. | |
1160 | */ | |
f5dfb531 AV |
1161 | if ((ctx->subsys_mask || ctx->none) && |
1162 | (ctx->subsys_mask != root->subsys_mask)) { | |
1592c9b2 TH |
1163 | if (!name_match) |
1164 | continue; | |
6678889f | 1165 | return -EBUSY; |
1592c9b2 TH |
1166 | } |
1167 | ||
f5dfb531 | 1168 | if (root->flags ^ ctx->flags) |
1592c9b2 TH |
1169 | pr_warn("new mount options do not match the existing superblock, will be ignored\n"); |
1170 | ||
cf6299b1 | 1171 | ctx->root = root; |
6678889f | 1172 | return 0; |
1592c9b2 TH |
1173 | } |
1174 | ||
1175 | /* | |
1176 | * No such thing, create a new one. name= matching without subsys | |
1177 | * specification is allowed for already existing hierarchies but we | |
1178 | * can't create new one without subsys specification. | |
1179 | */ | |
6678889f | 1180 | if (!ctx->subsys_mask && !ctx->none) |
58c025f0 | 1181 | return invalfc(fc, "No subsys list or none specified"); |
1592c9b2 TH |
1182 | |
1183 | /* Hierarchies may only be created in the initial cgroup namespace. */ | |
cca8f327 | 1184 | if (ctx->ns != &init_cgroup_ns) |
6678889f | 1185 | return -EPERM; |
1592c9b2 TH |
1186 | |
1187 | root = kzalloc(sizeof(*root), GFP_KERNEL); | |
6678889f AV |
1188 | if (!root) |
1189 | return -ENOMEM; | |
1592c9b2 | 1190 | |
cf6299b1 AV |
1191 | ctx->root = root; |
1192 | init_cgroup_root(ctx); | |
1592c9b2 | 1193 | |
f5dfb531 | 1194 | ret = cgroup_setup_root(root, ctx->subsys_mask); |
1592c9b2 TH |
1195 | if (ret) |
1196 | cgroup_free_root(root); | |
6678889f AV |
1197 | return ret; |
1198 | } | |
1199 | ||
1200 | int cgroup1_get_tree(struct fs_context *fc) | |
1201 | { | |
6678889f AV |
1202 | struct cgroup_fs_context *ctx = cgroup_fc2context(fc); |
1203 | int ret; | |
1204 | ||
1205 | /* Check if the caller has permission to mount. */ | |
cca8f327 | 1206 | if (!ns_capable(ctx->ns->user_ns, CAP_SYS_ADMIN)) |
6678889f AV |
1207 | return -EPERM; |
1208 | ||
1209 | cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp); | |
1210 | ||
1211 | ret = cgroup1_root_to_use(fc); | |
1212 | if (!ret && !percpu_ref_tryget_live(&ctx->root->cgrp.self.refcnt)) | |
1213 | ret = 1; /* restart */ | |
1592c9b2 | 1214 | |
1592c9b2 | 1215 | mutex_unlock(&cgroup_mutex); |
1592c9b2 | 1216 | |
6678889f | 1217 | if (!ret) |
cca8f327 | 1218 | ret = cgroup_do_get_tree(fc); |
6678889f AV |
1219 | |
1220 | if (!ret && percpu_ref_is_dying(&ctx->root->cgrp.self.refcnt)) { | |
1e7107c5 | 1221 | fc_drop_locked(fc); |
6678889f AV |
1222 | ret = 1; |
1223 | } | |
1224 | ||
1225 | if (unlikely(ret > 0)) { | |
35ac1184 | 1226 | msleep(10); |
7feeef58 | 1227 | return restart_syscall(); |
9732adc5 | 1228 | } |
71d883c3 | 1229 | return ret; |
1592c9b2 TH |
1230 | } |
1231 | ||
0a268dbd TH |
1232 | static int __init cgroup1_wq_init(void) |
1233 | { | |
1234 | /* | |
1235 | * Used to destroy pidlists and separate to serve as flush domain. | |
1236 | * Cap @max_active to 1 too. | |
1237 | */ | |
1238 | cgroup_pidlist_destroy_wq = alloc_workqueue("cgroup_pidlist_destroy", | |
1239 | 0, 1); | |
1240 | BUG_ON(!cgroup_pidlist_destroy_wq); | |
1241 | return 0; | |
1242 | } | |
1243 | core_initcall(cgroup1_wq_init); | |
1244 | ||
1245 | static int __init cgroup_no_v1(char *str) | |
1246 | { | |
1247 | struct cgroup_subsys *ss; | |
1248 | char *token; | |
1249 | int i; | |
1250 | ||
1251 | while ((token = strsep(&str, ",")) != NULL) { | |
1252 | if (!*token) | |
1253 | continue; | |
1254 | ||
1255 | if (!strcmp(token, "all")) { | |
1256 | cgroup_no_v1_mask = U16_MAX; | |
3fc9c12d TH |
1257 | continue; |
1258 | } | |
1259 | ||
1260 | if (!strcmp(token, "named")) { | |
1261 | cgroup_no_v1_named = true; | |
1262 | continue; | |
0a268dbd TH |
1263 | } |
1264 | ||
1265 | for_each_subsys(ss, i) { | |
1266 | if (strcmp(token, ss->name) && | |
1267 | strcmp(token, ss->legacy_name)) | |
1268 | continue; | |
1269 | ||
1270 | cgroup_no_v1_mask |= 1 << i; | |
1271 | } | |
1272 | } | |
1273 | return 1; | |
1274 | } | |
1275 | __setup("cgroup_no_v1=", cgroup_no_v1); |