1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* Daemon interface
3 *
4 * Copyright (C) 2007, 2021 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8 #include <linux/module.h>
9 #include <linux/init.h>
10 #include <linux/sched.h>
11 #include <linux/completion.h>
12 #include <linux/slab.h>
13 #include <linux/fs.h>
14 #include <linux/file.h>
15 #include <linux/namei.h>
16 #include <linux/poll.h>
17 #include <linux/mount.h>
18 #include <linux/statfs.h>
19 #include <linux/ctype.h>
20 #include <linux/string.h>
21 #include <linux/fs_struct.h>
22 #include "internal.h"
23
24 static int cachefiles_daemon_open(struct inode *, struct file *);
25 static int cachefiles_daemon_release(struct inode *, struct file *);
26 static ssize_t cachefiles_daemon_read(struct file *, char __user *, size_t,
27 loff_t *);
28 static ssize_t cachefiles_daemon_write(struct file *, const char __user *,
29 size_t, loff_t *);
30 static __poll_t cachefiles_daemon_poll(struct file *,
31 struct poll_table_struct *);
32 static int cachefiles_daemon_frun(struct cachefiles_cache *, char *);
33 static int cachefiles_daemon_fcull(struct cachefiles_cache *, char *);
34 static int cachefiles_daemon_fstop(struct cachefiles_cache *, char *);
35 static int cachefiles_daemon_brun(struct cachefiles_cache *, char *);
36 static int cachefiles_daemon_bcull(struct cachefiles_cache *, char *);
37 static int cachefiles_daemon_bstop(struct cachefiles_cache *, char *);
38 static int cachefiles_daemon_cull(struct cachefiles_cache *, char *);
39 static int cachefiles_daemon_debug(struct cachefiles_cache *, char *);
40 static int cachefiles_daemon_dir(struct cachefiles_cache *, char *);
41 static int cachefiles_daemon_inuse(struct cachefiles_cache *, char *);
42 static int cachefiles_daemon_secctx(struct cachefiles_cache *, char *);
43 static int cachefiles_daemon_tag(struct cachefiles_cache *, char *);
44 static int cachefiles_daemon_bind(struct cachefiles_cache *, char *);
45 static void cachefiles_daemon_unbind(struct cachefiles_cache *);
46
47 static unsigned long cachefiles_open;
48
49 const struct file_operations cachefiles_daemon_fops = {
50 .owner = THIS_MODULE,
51 .open = cachefiles_daemon_open,
52 .release = cachefiles_daemon_release,
53 .read = cachefiles_daemon_read,
54 .write = cachefiles_daemon_write,
55 .poll = cachefiles_daemon_poll,
56 .llseek = noop_llseek,
57 };
58
59 struct cachefiles_daemon_cmd {
60 char name[8];
61 int (*handler)(struct cachefiles_cache *cache, char *args);
62 };
63
64 static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = {
65 { "bind", cachefiles_daemon_bind },
66 { "brun", cachefiles_daemon_brun },
67 { "bcull", cachefiles_daemon_bcull },
68 { "bstop", cachefiles_daemon_bstop },
69 { "cull", cachefiles_daemon_cull },
70 { "debug", cachefiles_daemon_debug },
71 { "dir", cachefiles_daemon_dir },
72 { "frun", cachefiles_daemon_frun },
73 { "fcull", cachefiles_daemon_fcull },
74 { "fstop", cachefiles_daemon_fstop },
75 { "inuse", cachefiles_daemon_inuse },
76 { "secctx", cachefiles_daemon_secctx },
77 { "tag", cachefiles_daemon_tag },
78 #ifdef CONFIG_CACHEFILES_ONDEMAND
79 { "copen", cachefiles_ondemand_copen },
80 { "restore", cachefiles_ondemand_restore },
81 #endif
82 { "", NULL }
83 };
84
85
86 /*
87 * Prepare a cache for caching.
88 */
cachefiles_daemon_open(struct inode * inode,struct file * file)89 static int cachefiles_daemon_open(struct inode *inode, struct file *file)
90 {
91 struct cachefiles_cache *cache;
92
93 _enter("");
94
95 /* only the superuser may do this */
96 if (!capable(CAP_SYS_ADMIN))
97 return -EPERM;
98
99 /* the cachefiles device may only be open once at a time */
100 if (xchg(&cachefiles_open, 1) == 1)
101 return -EBUSY;
102
103 /* allocate a cache record */
104 cache = kzalloc(sizeof(struct cachefiles_cache), GFP_KERNEL);
105 if (!cache) {
106 cachefiles_open = 0;
107 return -ENOMEM;
108 }
109
110 mutex_init(&cache->daemon_mutex);
111 init_waitqueue_head(&cache->daemon_pollwq);
112 INIT_LIST_HEAD(&cache->volumes);
113 INIT_LIST_HEAD(&cache->object_list);
114 spin_lock_init(&cache->object_list_lock);
115 refcount_set(&cache->unbind_pincount, 1);
116 xa_init_flags(&cache->reqs, XA_FLAGS_ALLOC);
117 xa_init_flags(&cache->ondemand_ids, XA_FLAGS_ALLOC1);
118
119 /* set default caching limits
120 * - limit at 1% free space and/or free files
121 * - cull below 5% free space and/or free files
122 * - cease culling above 7% free space and/or free files
123 */
124 cache->frun_percent = 7;
125 cache->fcull_percent = 5;
126 cache->fstop_percent = 1;
127 cache->brun_percent = 7;
128 cache->bcull_percent = 5;
129 cache->bstop_percent = 1;
130
131 file->private_data = cache;
132 cache->cachefilesd = file;
133 return 0;
134 }
135
cachefiles_flush_reqs(struct cachefiles_cache * cache)136 void cachefiles_flush_reqs(struct cachefiles_cache *cache)
137 {
138 struct xarray *xa = &cache->reqs;
139 struct cachefiles_req *req;
140 unsigned long index;
141
142 /*
143 * Make sure the following two operations won't be reordered.
144 * 1) set CACHEFILES_DEAD bit
145 * 2) flush requests in the xarray
146 * Otherwise the request may be enqueued after xarray has been
147 * flushed, leaving the orphan request never being completed.
148 *
149 * CPU 1 CPU 2
150 * ===== =====
151 * flush requests in the xarray
152 * test CACHEFILES_DEAD bit
153 * enqueue the request
154 * set CACHEFILES_DEAD bit
155 */
156 smp_mb();
157
158 xa_lock(xa);
159 xa_for_each(xa, index, req) {
160 req->error = -EIO;
161 complete(&req->done);
162 __xa_erase(xa, index);
163 }
164 xa_unlock(xa);
165
166 xa_destroy(&cache->reqs);
167 xa_destroy(&cache->ondemand_ids);
168 }
169
cachefiles_put_unbind_pincount(struct cachefiles_cache * cache)170 void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache)
171 {
172 if (refcount_dec_and_test(&cache->unbind_pincount)) {
173 cachefiles_daemon_unbind(cache);
174 cachefiles_open = 0;
175 kfree(cache);
176 }
177 }
178
cachefiles_get_unbind_pincount(struct cachefiles_cache * cache)179 void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache)
180 {
181 refcount_inc(&cache->unbind_pincount);
182 }
183
184 /*
185 * Release a cache.
186 */
cachefiles_daemon_release(struct inode * inode,struct file * file)187 static int cachefiles_daemon_release(struct inode *inode, struct file *file)
188 {
189 struct cachefiles_cache *cache = file->private_data;
190
191 _enter("");
192
193 ASSERT(cache);
194
195 set_bit(CACHEFILES_DEAD, &cache->flags);
196
197 if (cachefiles_in_ondemand_mode(cache))
198 cachefiles_flush_reqs(cache);
199
200 /* clean up the control file interface */
201 cache->cachefilesd = NULL;
202 file->private_data = NULL;
203
204 cachefiles_put_unbind_pincount(cache);
205
206 _leave("");
207 return 0;
208 }
209
cachefiles_do_daemon_read(struct cachefiles_cache * cache,char __user * _buffer,size_t buflen)210 static ssize_t cachefiles_do_daemon_read(struct cachefiles_cache *cache,
211 char __user *_buffer, size_t buflen)
212 {
213 unsigned long long b_released;
214 unsigned f_released;
215 char buffer[256];
216 int n;
217
218 /* check how much space the cache has */
219 cachefiles_has_space(cache, 0, 0, cachefiles_has_space_check);
220
221 /* summarise */
222 f_released = atomic_xchg(&cache->f_released, 0);
223 b_released = atomic_long_xchg(&cache->b_released, 0);
224 clear_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
225
226 n = snprintf(buffer, sizeof(buffer),
227 "cull=%c"
228 " frun=%llx"
229 " fcull=%llx"
230 " fstop=%llx"
231 " brun=%llx"
232 " bcull=%llx"
233 " bstop=%llx"
234 " freleased=%x"
235 " breleased=%llx",
236 test_bit(CACHEFILES_CULLING, &cache->flags) ? '1' : '0',
237 (unsigned long long) cache->frun,
238 (unsigned long long) cache->fcull,
239 (unsigned long long) cache->fstop,
240 (unsigned long long) cache->brun,
241 (unsigned long long) cache->bcull,
242 (unsigned long long) cache->bstop,
243 f_released,
244 b_released);
245
246 if (n > buflen)
247 return -EMSGSIZE;
248
249 if (copy_to_user(_buffer, buffer, n) != 0)
250 return -EFAULT;
251
252 return n;
253 }
254
255 /*
256 * Read the cache state.
257 */
cachefiles_daemon_read(struct file * file,char __user * _buffer,size_t buflen,loff_t * pos)258 static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer,
259 size_t buflen, loff_t *pos)
260 {
261 struct cachefiles_cache *cache = file->private_data;
262
263 //_enter(",,%zu,", buflen);
264
265 if (!test_bit(CACHEFILES_READY, &cache->flags))
266 return 0;
267
268 if (cachefiles_in_ondemand_mode(cache))
269 return cachefiles_ondemand_daemon_read(cache, _buffer, buflen);
270 else
271 return cachefiles_do_daemon_read(cache, _buffer, buflen);
272 }
273
274 /*
275 * Take a command from cachefilesd, parse it and act on it.
276 */
cachefiles_daemon_write(struct file * file,const char __user * _data,size_t datalen,loff_t * pos)277 static ssize_t cachefiles_daemon_write(struct file *file,
278 const char __user *_data,
279 size_t datalen,
280 loff_t *pos)
281 {
282 const struct cachefiles_daemon_cmd *cmd;
283 struct cachefiles_cache *cache = file->private_data;
284 ssize_t ret;
285 char *data, *args, *cp;
286
287 //_enter(",,%zu,", datalen);
288
289 ASSERT(cache);
290
291 if (test_bit(CACHEFILES_DEAD, &cache->flags))
292 return -EIO;
293
294 if (datalen > PAGE_SIZE - 1)
295 return -EOPNOTSUPP;
296
297 /* drag the command string into the kernel so we can parse it */
298 data = memdup_user_nul(_data, datalen);
299 if (IS_ERR(data))
300 return PTR_ERR(data);
301
302 ret = -EINVAL;
303 if (memchr(data, '\0', datalen))
304 goto error;
305
306 /* strip any newline */
307 cp = memchr(data, '\n', datalen);
308 if (cp) {
309 if (cp == data)
310 goto error;
311
312 *cp = '\0';
313 }
314
315 /* parse the command */
316 ret = -EOPNOTSUPP;
317
318 for (args = data; *args; args++)
319 if (isspace(*args))
320 break;
321 if (*args) {
322 if (args == data)
323 goto error;
324 *args = '\0';
325 args = skip_spaces(++args);
326 }
327
328 /* run the appropriate command handler */
329 for (cmd = cachefiles_daemon_cmds; cmd->name[0]; cmd++)
330 if (strcmp(cmd->name, data) == 0)
331 goto found_command;
332
333 error:
334 kfree(data);
335 //_leave(" = %zd", ret);
336 return ret;
337
338 found_command:
339 mutex_lock(&cache->daemon_mutex);
340
341 ret = -EIO;
342 if (!test_bit(CACHEFILES_DEAD, &cache->flags))
343 ret = cmd->handler(cache, args);
344
345 mutex_unlock(&cache->daemon_mutex);
346
347 if (ret == 0)
348 ret = datalen;
349 goto error;
350 }
351
352 /*
353 * Poll for culling state
354 * - use EPOLLOUT to indicate culling state
355 */
cachefiles_daemon_poll(struct file * file,struct poll_table_struct * poll)356 static __poll_t cachefiles_daemon_poll(struct file *file,
357 struct poll_table_struct *poll)
358 {
359 struct cachefiles_cache *cache = file->private_data;
360 XA_STATE(xas, &cache->reqs, 0);
361 struct cachefiles_req *req;
362 __poll_t mask;
363
364 poll_wait(file, &cache->daemon_pollwq, poll);
365 mask = 0;
366
367 if (cachefiles_in_ondemand_mode(cache)) {
368 if (!xa_empty(&cache->reqs)) {
369 rcu_read_lock();
370 xas_for_each_marked(&xas, req, ULONG_MAX, CACHEFILES_REQ_NEW) {
371 if (!cachefiles_ondemand_is_reopening_read(req)) {
372 mask |= EPOLLIN;
373 break;
374 }
375 }
376 rcu_read_unlock();
377 }
378 } else {
379 if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
380 mask |= EPOLLIN;
381 }
382
383 if (test_bit(CACHEFILES_CULLING, &cache->flags))
384 mask |= EPOLLOUT;
385
386 return mask;
387 }
388
389 /*
390 * Give a range error for cache space constraints
391 * - can be tail-called
392 */
cachefiles_daemon_range_error(struct cachefiles_cache * cache,char * args)393 static int cachefiles_daemon_range_error(struct cachefiles_cache *cache,
394 char *args)
395 {
396 pr_err("Free space limits must be in range 0%%<=stop<cull<run<100%%\n");
397
398 return -EINVAL;
399 }
400
401 /*
402 * Set the percentage of files at which to stop culling
403 * - command: "frun <N>%"
404 */
cachefiles_daemon_frun(struct cachefiles_cache * cache,char * args)405 static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args)
406 {
407 unsigned long frun;
408
409 _enter(",%s", args);
410
411 if (!*args)
412 return -EINVAL;
413
414 frun = simple_strtoul(args, &args, 10);
415 if (args[0] != '%' || args[1] != '\0')
416 return -EINVAL;
417
418 if (frun <= cache->fcull_percent || frun >= 100)
419 return cachefiles_daemon_range_error(cache, args);
420
421 cache->frun_percent = frun;
422 return 0;
423 }
424
425 /*
426 * Set the percentage of files at which to start culling
427 * - command: "fcull <N>%"
428 */
cachefiles_daemon_fcull(struct cachefiles_cache * cache,char * args)429 static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args)
430 {
431 unsigned long fcull;
432
433 _enter(",%s", args);
434
435 if (!*args)
436 return -EINVAL;
437
438 fcull = simple_strtoul(args, &args, 10);
439 if (args[0] != '%' || args[1] != '\0')
440 return -EINVAL;
441
442 if (fcull <= cache->fstop_percent || fcull >= cache->frun_percent)
443 return cachefiles_daemon_range_error(cache, args);
444
445 cache->fcull_percent = fcull;
446 return 0;
447 }
448
449 /*
450 * Set the percentage of files at which to stop allocating
451 * - command: "fstop <N>%"
452 */
cachefiles_daemon_fstop(struct cachefiles_cache * cache,char * args)453 static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args)
454 {
455 unsigned long fstop;
456
457 _enter(",%s", args);
458
459 if (!*args)
460 return -EINVAL;
461
462 fstop = simple_strtoul(args, &args, 10);
463 if (args[0] != '%' || args[1] != '\0')
464 return -EINVAL;
465
466 if (fstop >= cache->fcull_percent)
467 return cachefiles_daemon_range_error(cache, args);
468
469 cache->fstop_percent = fstop;
470 return 0;
471 }
472
473 /*
474 * Set the percentage of blocks at which to stop culling
475 * - command: "brun <N>%"
476 */
cachefiles_daemon_brun(struct cachefiles_cache * cache,char * args)477 static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args)
478 {
479 unsigned long brun;
480
481 _enter(",%s", args);
482
483 if (!*args)
484 return -EINVAL;
485
486 brun = simple_strtoul(args, &args, 10);
487 if (args[0] != '%' || args[1] != '\0')
488 return -EINVAL;
489
490 if (brun <= cache->bcull_percent || brun >= 100)
491 return cachefiles_daemon_range_error(cache, args);
492
493 cache->brun_percent = brun;
494 return 0;
495 }
496
497 /*
498 * Set the percentage of blocks at which to start culling
499 * - command: "bcull <N>%"
500 */
cachefiles_daemon_bcull(struct cachefiles_cache * cache,char * args)501 static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args)
502 {
503 unsigned long bcull;
504
505 _enter(",%s", args);
506
507 if (!*args)
508 return -EINVAL;
509
510 bcull = simple_strtoul(args, &args, 10);
511 if (args[0] != '%' || args[1] != '\0')
512 return -EINVAL;
513
514 if (bcull <= cache->bstop_percent || bcull >= cache->brun_percent)
515 return cachefiles_daemon_range_error(cache, args);
516
517 cache->bcull_percent = bcull;
518 return 0;
519 }
520
521 /*
522 * Set the percentage of blocks at which to stop allocating
523 * - command: "bstop <N>%"
524 */
cachefiles_daemon_bstop(struct cachefiles_cache * cache,char * args)525 static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args)
526 {
527 unsigned long bstop;
528
529 _enter(",%s", args);
530
531 if (!*args)
532 return -EINVAL;
533
534 bstop = simple_strtoul(args, &args, 10);
535 if (args[0] != '%' || args[1] != '\0')
536 return -EINVAL;
537
538 if (bstop >= cache->bcull_percent)
539 return cachefiles_daemon_range_error(cache, args);
540
541 cache->bstop_percent = bstop;
542 return 0;
543 }
544
545 /*
546 * Set the cache directory
547 * - command: "dir <name>"
548 */
cachefiles_daemon_dir(struct cachefiles_cache * cache,char * args)549 static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args)
550 {
551 char *dir;
552
553 _enter(",%s", args);
554
555 if (!*args) {
556 pr_err("Empty directory specified\n");
557 return -EINVAL;
558 }
559
560 if (cache->rootdirname) {
561 pr_err("Second cache directory specified\n");
562 return -EEXIST;
563 }
564
565 dir = kstrdup(args, GFP_KERNEL);
566 if (!dir)
567 return -ENOMEM;
568
569 cache->rootdirname = dir;
570 return 0;
571 }
572
573 /*
574 * Set the cache security context
575 * - command: "secctx <ctx>"
576 */
cachefiles_daemon_secctx(struct cachefiles_cache * cache,char * args)577 static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args)
578 {
579 char *secctx;
580
581 _enter(",%s", args);
582
583 if (!*args) {
584 pr_err("Empty security context specified\n");
585 return -EINVAL;
586 }
587
588 if (cache->secctx) {
589 pr_err("Second security context specified\n");
590 return -EINVAL;
591 }
592
593 secctx = kstrdup(args, GFP_KERNEL);
594 if (!secctx)
595 return -ENOMEM;
596
597 cache->secctx = secctx;
598 return 0;
599 }
600
601 /*
602 * Set the cache tag
603 * - command: "tag <name>"
604 */
cachefiles_daemon_tag(struct cachefiles_cache * cache,char * args)605 static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args)
606 {
607 char *tag;
608
609 _enter(",%s", args);
610
611 if (!*args) {
612 pr_err("Empty tag specified\n");
613 return -EINVAL;
614 }
615
616 if (cache->tag)
617 return -EEXIST;
618
619 tag = kstrdup(args, GFP_KERNEL);
620 if (!tag)
621 return -ENOMEM;
622
623 cache->tag = tag;
624 return 0;
625 }
626
627 /*
628 * Request a node in the cache be culled from the current working directory
629 * - command: "cull <name>"
630 */
cachefiles_daemon_cull(struct cachefiles_cache * cache,char * args)631 static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args)
632 {
633 struct path path;
634 const struct cred *saved_cred;
635 int ret;
636
637 _enter(",%s", args);
638
639 if (strchr(args, '/'))
640 goto inval;
641
642 if (!test_bit(CACHEFILES_READY, &cache->flags)) {
643 pr_err("cull applied to unready cache\n");
644 return -EIO;
645 }
646
647 if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
648 pr_err("cull applied to dead cache\n");
649 return -EIO;
650 }
651
652 get_fs_pwd(current->fs, &path);
653
654 if (!d_can_lookup(path.dentry))
655 goto notdir;
656
657 cachefiles_begin_secure(cache, &saved_cred);
658 ret = cachefiles_cull(cache, path.dentry, args);
659 cachefiles_end_secure(cache, saved_cred);
660
661 path_put(&path);
662 _leave(" = %d", ret);
663 return ret;
664
665 notdir:
666 path_put(&path);
667 pr_err("cull command requires dirfd to be a directory\n");
668 return -ENOTDIR;
669
670 inval:
671 pr_err("cull command requires dirfd and filename\n");
672 return -EINVAL;
673 }
674
675 /*
676 * Set debugging mode
677 * - command: "debug <mask>"
678 */
cachefiles_daemon_debug(struct cachefiles_cache * cache,char * args)679 static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args)
680 {
681 unsigned long mask;
682
683 _enter(",%s", args);
684
685 mask = simple_strtoul(args, &args, 0);
686 if (args[0] != '\0')
687 goto inval;
688
689 cachefiles_debug = mask;
690 _leave(" = 0");
691 return 0;
692
693 inval:
694 pr_err("debug command requires mask\n");
695 return -EINVAL;
696 }
697
698 /*
699 * Find out whether an object in the current working directory is in use or not
700 * - command: "inuse <name>"
701 */
cachefiles_daemon_inuse(struct cachefiles_cache * cache,char * args)702 static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args)
703 {
704 struct path path;
705 const struct cred *saved_cred;
706 int ret;
707
708 //_enter(",%s", args);
709
710 if (strchr(args, '/'))
711 goto inval;
712
713 if (!test_bit(CACHEFILES_READY, &cache->flags)) {
714 pr_err("inuse applied to unready cache\n");
715 return -EIO;
716 }
717
718 if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
719 pr_err("inuse applied to dead cache\n");
720 return -EIO;
721 }
722
723 get_fs_pwd(current->fs, &path);
724
725 if (!d_can_lookup(path.dentry))
726 goto notdir;
727
728 cachefiles_begin_secure(cache, &saved_cred);
729 ret = cachefiles_check_in_use(cache, path.dentry, args);
730 cachefiles_end_secure(cache, saved_cred);
731
732 path_put(&path);
733 //_leave(" = %d", ret);
734 return ret;
735
736 notdir:
737 path_put(&path);
738 pr_err("inuse command requires dirfd to be a directory\n");
739 return -ENOTDIR;
740
741 inval:
742 pr_err("inuse command requires dirfd and filename\n");
743 return -EINVAL;
744 }
745
746 /*
747 * Bind a directory as a cache
748 */
cachefiles_daemon_bind(struct cachefiles_cache * cache,char * args)749 static int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args)
750 {
751 _enter("{%u,%u,%u,%u,%u,%u},%s",
752 cache->frun_percent,
753 cache->fcull_percent,
754 cache->fstop_percent,
755 cache->brun_percent,
756 cache->bcull_percent,
757 cache->bstop_percent,
758 args);
759
760 if (cache->fstop_percent >= cache->fcull_percent ||
761 cache->fcull_percent >= cache->frun_percent ||
762 cache->frun_percent >= 100)
763 return -ERANGE;
764
765 if (cache->bstop_percent >= cache->bcull_percent ||
766 cache->bcull_percent >= cache->brun_percent ||
767 cache->brun_percent >= 100)
768 return -ERANGE;
769
770 if (!cache->rootdirname) {
771 pr_err("No cache directory specified\n");
772 return -EINVAL;
773 }
774
775 /* Don't permit already bound caches to be re-bound */
776 if (test_bit(CACHEFILES_READY, &cache->flags)) {
777 pr_err("Cache already bound\n");
778 return -EBUSY;
779 }
780
781 if (IS_ENABLED(CONFIG_CACHEFILES_ONDEMAND)) {
782 if (!strcmp(args, "ondemand")) {
783 set_bit(CACHEFILES_ONDEMAND_MODE, &cache->flags);
784 } else if (*args) {
785 pr_err("Invalid argument to the 'bind' command\n");
786 return -EINVAL;
787 }
788 } else if (*args) {
789 pr_err("'bind' command doesn't take an argument\n");
790 return -EINVAL;
791 }
792
793 /* Make sure we have copies of the tag string */
794 if (!cache->tag) {
795 /*
796 * The tag string is released by the fops->release()
797 * function, so we don't release it on error here
798 */
799 cache->tag = kstrdup("CacheFiles", GFP_KERNEL);
800 if (!cache->tag)
801 return -ENOMEM;
802 }
803
804 return cachefiles_add_cache(cache);
805 }
806
807 /*
808 * Unbind a cache.
809 */
cachefiles_daemon_unbind(struct cachefiles_cache * cache)810 static void cachefiles_daemon_unbind(struct cachefiles_cache *cache)
811 {
812 _enter("");
813
814 if (test_bit(CACHEFILES_READY, &cache->flags))
815 cachefiles_withdraw_cache(cache);
816
817 cachefiles_put_directory(cache->graveyard);
818 cachefiles_put_directory(cache->store);
819 mntput(cache->mnt);
820 put_cred(cache->cache_cred);
821
822 kfree(cache->rootdirname);
823 kfree(cache->secctx);
824 kfree(cache->tag);
825
826 _leave("");
827 }
828