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 | */ |
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(size: 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(list: &cache->volumes); |
113 | INIT_LIST_HEAD(list: &cache->object_list); |
114 | spin_lock_init(&cache->object_list_lock); |
115 | refcount_set(r: &cache->unbind_pincount, n: 1); |
116 | xa_init_flags(xa: &cache->reqs, XA_FLAGS_ALLOC); |
117 | xa_init_flags(xa: &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 | |
136 | static 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 | } |
163 | xa_unlock(xa); |
164 | |
165 | xa_destroy(&cache->reqs); |
166 | xa_destroy(&cache->ondemand_ids); |
167 | } |
168 | |
169 | void cachefiles_put_unbind_pincount(struct cachefiles_cache *cache) |
170 | { |
171 | if (refcount_dec_and_test(r: &cache->unbind_pincount)) { |
172 | cachefiles_daemon_unbind(cache); |
173 | cachefiles_open = 0; |
174 | kfree(objp: cache); |
175 | } |
176 | } |
177 | |
178 | void cachefiles_get_unbind_pincount(struct cachefiles_cache *cache) |
179 | { |
180 | refcount_inc(r: &cache->unbind_pincount); |
181 | } |
182 | |
183 | /* |
184 | * Release a cache. |
185 | */ |
186 | static int cachefiles_daemon_release(struct inode *inode, struct file *file) |
187 | { |
188 | struct cachefiles_cache *cache = file->private_data; |
189 | |
190 | _enter("" ); |
191 | |
192 | ASSERT(cache); |
193 | |
194 | set_bit(CACHEFILES_DEAD, addr: &cache->flags); |
195 | |
196 | if (cachefiles_in_ondemand_mode(cache)) |
197 | cachefiles_flush_reqs(cache); |
198 | |
199 | /* clean up the control file interface */ |
200 | cache->cachefilesd = NULL; |
201 | file->private_data = NULL; |
202 | |
203 | cachefiles_put_unbind_pincount(cache); |
204 | |
205 | _leave("" ); |
206 | return 0; |
207 | } |
208 | |
209 | static ssize_t cachefiles_do_daemon_read(struct cachefiles_cache *cache, |
210 | char __user *_buffer, size_t buflen) |
211 | { |
212 | unsigned long long b_released; |
213 | unsigned f_released; |
214 | char buffer[256]; |
215 | int n; |
216 | |
217 | /* check how much space the cache has */ |
218 | cachefiles_has_space(cache, fnr: 0, bnr: 0, reason: cachefiles_has_space_check); |
219 | |
220 | /* summarise */ |
221 | f_released = atomic_xchg(v: &cache->f_released, new: 0); |
222 | b_released = atomic_long_xchg(v: &cache->b_released, new: 0); |
223 | clear_bit(CACHEFILES_STATE_CHANGED, addr: &cache->flags); |
224 | |
225 | n = snprintf(buf: buffer, size: sizeof(buffer), |
226 | fmt: "cull=%c" |
227 | " frun=%llx" |
228 | " fcull=%llx" |
229 | " fstop=%llx" |
230 | " brun=%llx" |
231 | " bcull=%llx" |
232 | " bstop=%llx" |
233 | " freleased=%x" |
234 | " breleased=%llx" , |
235 | test_bit(CACHEFILES_CULLING, &cache->flags) ? '1' : '0', |
236 | (unsigned long long) cache->frun, |
237 | (unsigned long long) cache->fcull, |
238 | (unsigned long long) cache->fstop, |
239 | (unsigned long long) cache->brun, |
240 | (unsigned long long) cache->bcull, |
241 | (unsigned long long) cache->bstop, |
242 | f_released, |
243 | b_released); |
244 | |
245 | if (n > buflen) |
246 | return -EMSGSIZE; |
247 | |
248 | if (copy_to_user(to: _buffer, from: buffer, n) != 0) |
249 | return -EFAULT; |
250 | |
251 | return n; |
252 | } |
253 | |
254 | /* |
255 | * Read the cache state. |
256 | */ |
257 | static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer, |
258 | size_t buflen, loff_t *pos) |
259 | { |
260 | struct cachefiles_cache *cache = file->private_data; |
261 | |
262 | //_enter(",,%zu,", buflen); |
263 | |
264 | if (!test_bit(CACHEFILES_READY, &cache->flags)) |
265 | return 0; |
266 | |
267 | if (cachefiles_in_ondemand_mode(cache)) |
268 | return cachefiles_ondemand_daemon_read(cache, _buffer, buflen); |
269 | else |
270 | return cachefiles_do_daemon_read(cache, _buffer, buflen); |
271 | } |
272 | |
273 | /* |
274 | * Take a command from cachefilesd, parse it and act on it. |
275 | */ |
276 | static ssize_t cachefiles_daemon_write(struct file *file, |
277 | const char __user *_data, |
278 | size_t datalen, |
279 | loff_t *pos) |
280 | { |
281 | const struct cachefiles_daemon_cmd *cmd; |
282 | struct cachefiles_cache *cache = file->private_data; |
283 | ssize_t ret; |
284 | char *data, *args, *cp; |
285 | |
286 | //_enter(",,%zu,", datalen); |
287 | |
288 | ASSERT(cache); |
289 | |
290 | if (test_bit(CACHEFILES_DEAD, &cache->flags)) |
291 | return -EIO; |
292 | |
293 | if (datalen > PAGE_SIZE - 1) |
294 | return -EOPNOTSUPP; |
295 | |
296 | /* drag the command string into the kernel so we can parse it */ |
297 | data = memdup_user_nul(_data, datalen); |
298 | if (IS_ERR(ptr: data)) |
299 | return PTR_ERR(ptr: data); |
300 | |
301 | ret = -EINVAL; |
302 | if (memchr(p: data, c: '\0', size: datalen)) |
303 | goto error; |
304 | |
305 | /* strip any newline */ |
306 | cp = memchr(p: data, c: '\n', size: datalen); |
307 | if (cp) { |
308 | if (cp == data) |
309 | goto error; |
310 | |
311 | *cp = '\0'; |
312 | } |
313 | |
314 | /* parse the command */ |
315 | ret = -EOPNOTSUPP; |
316 | |
317 | for (args = data; *args; args++) |
318 | if (isspace(*args)) |
319 | break; |
320 | if (*args) { |
321 | if (args == data) |
322 | goto error; |
323 | *args = '\0'; |
324 | args = skip_spaces(++args); |
325 | } |
326 | |
327 | /* run the appropriate command handler */ |
328 | for (cmd = cachefiles_daemon_cmds; cmd->name[0]; cmd++) |
329 | if (strcmp(cmd->name, data) == 0) |
330 | goto found_command; |
331 | |
332 | error: |
333 | kfree(objp: data); |
334 | //_leave(" = %zd", ret); |
335 | return ret; |
336 | |
337 | found_command: |
338 | mutex_lock(&cache->daemon_mutex); |
339 | |
340 | ret = -EIO; |
341 | if (!test_bit(CACHEFILES_DEAD, &cache->flags)) |
342 | ret = cmd->handler(cache, args); |
343 | |
344 | mutex_unlock(lock: &cache->daemon_mutex); |
345 | |
346 | if (ret == 0) |
347 | ret = datalen; |
348 | goto error; |
349 | } |
350 | |
351 | /* |
352 | * Poll for culling state |
353 | * - use EPOLLOUT to indicate culling state |
354 | */ |
355 | static __poll_t cachefiles_daemon_poll(struct file *file, |
356 | struct poll_table_struct *poll) |
357 | { |
358 | struct cachefiles_cache *cache = file->private_data; |
359 | XA_STATE(xas, &cache->reqs, 0); |
360 | struct cachefiles_req *req; |
361 | __poll_t mask; |
362 | |
363 | poll_wait(filp: file, wait_address: &cache->daemon_pollwq, p: poll); |
364 | mask = 0; |
365 | |
366 | if (cachefiles_in_ondemand_mode(cache)) { |
367 | if (!xa_empty(xa: &cache->reqs)) { |
368 | rcu_read_lock(); |
369 | xas_for_each_marked(&xas, req, ULONG_MAX, CACHEFILES_REQ_NEW) { |
370 | if (!cachefiles_ondemand_is_reopening_read(req)) { |
371 | mask |= EPOLLIN; |
372 | break; |
373 | } |
374 | } |
375 | rcu_read_unlock(); |
376 | } |
377 | } else { |
378 | if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags)) |
379 | mask |= EPOLLIN; |
380 | } |
381 | |
382 | if (test_bit(CACHEFILES_CULLING, &cache->flags)) |
383 | mask |= EPOLLOUT; |
384 | |
385 | return mask; |
386 | } |
387 | |
388 | /* |
389 | * Give a range error for cache space constraints |
390 | * - can be tail-called |
391 | */ |
392 | static int cachefiles_daemon_range_error(struct cachefiles_cache *cache, |
393 | char *args) |
394 | { |
395 | pr_err("Free space limits must be in range 0%%<=stop<cull<run<100%%\n" ); |
396 | |
397 | return -EINVAL; |
398 | } |
399 | |
400 | /* |
401 | * Set the percentage of files at which to stop culling |
402 | * - command: "frun <N>%" |
403 | */ |
404 | static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args) |
405 | { |
406 | unsigned long frun; |
407 | |
408 | _enter(",%s" , args); |
409 | |
410 | if (!*args) |
411 | return -EINVAL; |
412 | |
413 | frun = simple_strtoul(args, &args, 10); |
414 | if (args[0] != '%' || args[1] != '\0') |
415 | return -EINVAL; |
416 | |
417 | if (frun <= cache->fcull_percent || frun >= 100) |
418 | return cachefiles_daemon_range_error(cache, args); |
419 | |
420 | cache->frun_percent = frun; |
421 | return 0; |
422 | } |
423 | |
424 | /* |
425 | * Set the percentage of files at which to start culling |
426 | * - command: "fcull <N>%" |
427 | */ |
428 | static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args) |
429 | { |
430 | unsigned long fcull; |
431 | |
432 | _enter(",%s" , args); |
433 | |
434 | if (!*args) |
435 | return -EINVAL; |
436 | |
437 | fcull = simple_strtoul(args, &args, 10); |
438 | if (args[0] != '%' || args[1] != '\0') |
439 | return -EINVAL; |
440 | |
441 | if (fcull <= cache->fstop_percent || fcull >= cache->frun_percent) |
442 | return cachefiles_daemon_range_error(cache, args); |
443 | |
444 | cache->fcull_percent = fcull; |
445 | return 0; |
446 | } |
447 | |
448 | /* |
449 | * Set the percentage of files at which to stop allocating |
450 | * - command: "fstop <N>%" |
451 | */ |
452 | static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args) |
453 | { |
454 | unsigned long fstop; |
455 | |
456 | _enter(",%s" , args); |
457 | |
458 | if (!*args) |
459 | return -EINVAL; |
460 | |
461 | fstop = simple_strtoul(args, &args, 10); |
462 | if (args[0] != '%' || args[1] != '\0') |
463 | return -EINVAL; |
464 | |
465 | if (fstop >= cache->fcull_percent) |
466 | return cachefiles_daemon_range_error(cache, args); |
467 | |
468 | cache->fstop_percent = fstop; |
469 | return 0; |
470 | } |
471 | |
472 | /* |
473 | * Set the percentage of blocks at which to stop culling |
474 | * - command: "brun <N>%" |
475 | */ |
476 | static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args) |
477 | { |
478 | unsigned long brun; |
479 | |
480 | _enter(",%s" , args); |
481 | |
482 | if (!*args) |
483 | return -EINVAL; |
484 | |
485 | brun = simple_strtoul(args, &args, 10); |
486 | if (args[0] != '%' || args[1] != '\0') |
487 | return -EINVAL; |
488 | |
489 | if (brun <= cache->bcull_percent || brun >= 100) |
490 | return cachefiles_daemon_range_error(cache, args); |
491 | |
492 | cache->brun_percent = brun; |
493 | return 0; |
494 | } |
495 | |
496 | /* |
497 | * Set the percentage of blocks at which to start culling |
498 | * - command: "bcull <N>%" |
499 | */ |
500 | static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args) |
501 | { |
502 | unsigned long bcull; |
503 | |
504 | _enter(",%s" , args); |
505 | |
506 | if (!*args) |
507 | return -EINVAL; |
508 | |
509 | bcull = simple_strtoul(args, &args, 10); |
510 | if (args[0] != '%' || args[1] != '\0') |
511 | return -EINVAL; |
512 | |
513 | if (bcull <= cache->bstop_percent || bcull >= cache->brun_percent) |
514 | return cachefiles_daemon_range_error(cache, args); |
515 | |
516 | cache->bcull_percent = bcull; |
517 | return 0; |
518 | } |
519 | |
520 | /* |
521 | * Set the percentage of blocks at which to stop allocating |
522 | * - command: "bstop <N>%" |
523 | */ |
524 | static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args) |
525 | { |
526 | unsigned long bstop; |
527 | |
528 | _enter(",%s" , args); |
529 | |
530 | if (!*args) |
531 | return -EINVAL; |
532 | |
533 | bstop = simple_strtoul(args, &args, 10); |
534 | if (args[0] != '%' || args[1] != '\0') |
535 | return -EINVAL; |
536 | |
537 | if (bstop >= cache->bcull_percent) |
538 | return cachefiles_daemon_range_error(cache, args); |
539 | |
540 | cache->bstop_percent = bstop; |
541 | return 0; |
542 | } |
543 | |
544 | /* |
545 | * Set the cache directory |
546 | * - command: "dir <name>" |
547 | */ |
548 | static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args) |
549 | { |
550 | char *dir; |
551 | |
552 | _enter(",%s" , args); |
553 | |
554 | if (!*args) { |
555 | pr_err("Empty directory specified\n" ); |
556 | return -EINVAL; |
557 | } |
558 | |
559 | if (cache->rootdirname) { |
560 | pr_err("Second cache directory specified\n" ); |
561 | return -EEXIST; |
562 | } |
563 | |
564 | dir = kstrdup(s: args, GFP_KERNEL); |
565 | if (!dir) |
566 | return -ENOMEM; |
567 | |
568 | cache->rootdirname = dir; |
569 | return 0; |
570 | } |
571 | |
572 | /* |
573 | * Set the cache security context |
574 | * - command: "secctx <ctx>" |
575 | */ |
576 | static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args) |
577 | { |
578 | char *secctx; |
579 | |
580 | _enter(",%s" , args); |
581 | |
582 | if (!*args) { |
583 | pr_err("Empty security context specified\n" ); |
584 | return -EINVAL; |
585 | } |
586 | |
587 | if (cache->secctx) { |
588 | pr_err("Second security context specified\n" ); |
589 | return -EINVAL; |
590 | } |
591 | |
592 | secctx = kstrdup(s: args, GFP_KERNEL); |
593 | if (!secctx) |
594 | return -ENOMEM; |
595 | |
596 | cache->secctx = secctx; |
597 | return 0; |
598 | } |
599 | |
600 | /* |
601 | * Set the cache tag |
602 | * - command: "tag <name>" |
603 | */ |
604 | static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args) |
605 | { |
606 | char *tag; |
607 | |
608 | _enter(",%s" , args); |
609 | |
610 | if (!*args) { |
611 | pr_err("Empty tag specified\n" ); |
612 | return -EINVAL; |
613 | } |
614 | |
615 | if (cache->tag) |
616 | return -EEXIST; |
617 | |
618 | tag = kstrdup(s: args, GFP_KERNEL); |
619 | if (!tag) |
620 | return -ENOMEM; |
621 | |
622 | cache->tag = tag; |
623 | return 0; |
624 | } |
625 | |
626 | /* |
627 | * Request a node in the cache be culled from the current working directory |
628 | * - command: "cull <name>" |
629 | */ |
630 | static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args) |
631 | { |
632 | struct path path; |
633 | const struct cred *saved_cred; |
634 | int ret; |
635 | |
636 | _enter(",%s" , args); |
637 | |
638 | if (strchr(args, '/')) |
639 | goto inval; |
640 | |
641 | if (!test_bit(CACHEFILES_READY, &cache->flags)) { |
642 | pr_err("cull applied to unready cache\n" ); |
643 | return -EIO; |
644 | } |
645 | |
646 | if (test_bit(CACHEFILES_DEAD, &cache->flags)) { |
647 | pr_err("cull applied to dead cache\n" ); |
648 | return -EIO; |
649 | } |
650 | |
651 | get_fs_pwd(current->fs, pwd: &path); |
652 | |
653 | if (!d_can_lookup(dentry: path.dentry)) |
654 | goto notdir; |
655 | |
656 | cachefiles_begin_secure(cache, saved_cred: &saved_cred); |
657 | ret = cachefiles_cull(cache, dir: path.dentry, filename: args); |
658 | cachefiles_end_secure(cache, saved_cred); |
659 | |
660 | path_put(&path); |
661 | _leave(" = %d" , ret); |
662 | return ret; |
663 | |
664 | notdir: |
665 | path_put(&path); |
666 | pr_err("cull command requires dirfd to be a directory\n" ); |
667 | return -ENOTDIR; |
668 | |
669 | inval: |
670 | pr_err("cull command requires dirfd and filename\n" ); |
671 | return -EINVAL; |
672 | } |
673 | |
674 | /* |
675 | * Set debugging mode |
676 | * - command: "debug <mask>" |
677 | */ |
678 | static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args) |
679 | { |
680 | unsigned long mask; |
681 | |
682 | _enter(",%s" , args); |
683 | |
684 | mask = simple_strtoul(args, &args, 0); |
685 | if (args[0] != '\0') |
686 | goto inval; |
687 | |
688 | cachefiles_debug = mask; |
689 | _leave(" = 0" ); |
690 | return 0; |
691 | |
692 | inval: |
693 | pr_err("debug command requires mask\n" ); |
694 | return -EINVAL; |
695 | } |
696 | |
697 | /* |
698 | * Find out whether an object in the current working directory is in use or not |
699 | * - command: "inuse <name>" |
700 | */ |
701 | static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args) |
702 | { |
703 | struct path path; |
704 | const struct cred *saved_cred; |
705 | int ret; |
706 | |
707 | //_enter(",%s", args); |
708 | |
709 | if (strchr(args, '/')) |
710 | goto inval; |
711 | |
712 | if (!test_bit(CACHEFILES_READY, &cache->flags)) { |
713 | pr_err("inuse applied to unready cache\n" ); |
714 | return -EIO; |
715 | } |
716 | |
717 | if (test_bit(CACHEFILES_DEAD, &cache->flags)) { |
718 | pr_err("inuse applied to dead cache\n" ); |
719 | return -EIO; |
720 | } |
721 | |
722 | get_fs_pwd(current->fs, pwd: &path); |
723 | |
724 | if (!d_can_lookup(dentry: path.dentry)) |
725 | goto notdir; |
726 | |
727 | cachefiles_begin_secure(cache, saved_cred: &saved_cred); |
728 | ret = cachefiles_check_in_use(cache, dir: path.dentry, filename: args); |
729 | cachefiles_end_secure(cache, saved_cred); |
730 | |
731 | path_put(&path); |
732 | //_leave(" = %d", ret); |
733 | return ret; |
734 | |
735 | notdir: |
736 | path_put(&path); |
737 | pr_err("inuse command requires dirfd to be a directory\n" ); |
738 | return -ENOTDIR; |
739 | |
740 | inval: |
741 | pr_err("inuse command requires dirfd and filename\n" ); |
742 | return -EINVAL; |
743 | } |
744 | |
745 | /* |
746 | * Bind a directory as a cache |
747 | */ |
748 | static int cachefiles_daemon_bind(struct cachefiles_cache *cache, char *args) |
749 | { |
750 | _enter("{%u,%u,%u,%u,%u,%u},%s" , |
751 | cache->frun_percent, |
752 | cache->fcull_percent, |
753 | cache->fstop_percent, |
754 | cache->brun_percent, |
755 | cache->bcull_percent, |
756 | cache->bstop_percent, |
757 | args); |
758 | |
759 | if (cache->fstop_percent >= cache->fcull_percent || |
760 | cache->fcull_percent >= cache->frun_percent || |
761 | cache->frun_percent >= 100) |
762 | return -ERANGE; |
763 | |
764 | if (cache->bstop_percent >= cache->bcull_percent || |
765 | cache->bcull_percent >= cache->brun_percent || |
766 | cache->brun_percent >= 100) |
767 | return -ERANGE; |
768 | |
769 | if (!cache->rootdirname) { |
770 | pr_err("No cache directory specified\n" ); |
771 | return -EINVAL; |
772 | } |
773 | |
774 | /* Don't permit already bound caches to be re-bound */ |
775 | if (test_bit(CACHEFILES_READY, &cache->flags)) { |
776 | pr_err("Cache already bound\n" ); |
777 | return -EBUSY; |
778 | } |
779 | |
780 | if (IS_ENABLED(CONFIG_CACHEFILES_ONDEMAND)) { |
781 | if (!strcmp(args, "ondemand" )) { |
782 | set_bit(CACHEFILES_ONDEMAND_MODE, addr: &cache->flags); |
783 | } else if (*args) { |
784 | pr_err("Invalid argument to the 'bind' command\n" ); |
785 | return -EINVAL; |
786 | } |
787 | } else if (*args) { |
788 | pr_err("'bind' command doesn't take an argument\n" ); |
789 | return -EINVAL; |
790 | } |
791 | |
792 | /* Make sure we have copies of the tag string */ |
793 | if (!cache->tag) { |
794 | /* |
795 | * The tag string is released by the fops->release() |
796 | * function, so we don't release it on error here |
797 | */ |
798 | cache->tag = kstrdup(s: "CacheFiles" , GFP_KERNEL); |
799 | if (!cache->tag) |
800 | return -ENOMEM; |
801 | } |
802 | |
803 | return cachefiles_add_cache(cache); |
804 | } |
805 | |
806 | /* |
807 | * Unbind a cache. |
808 | */ |
809 | static void cachefiles_daemon_unbind(struct cachefiles_cache *cache) |
810 | { |
811 | _enter("" ); |
812 | |
813 | if (test_bit(CACHEFILES_READY, &cache->flags)) |
814 | cachefiles_withdraw_cache(cache); |
815 | |
816 | cachefiles_put_directory(dir: cache->graveyard); |
817 | cachefiles_put_directory(dir: cache->store); |
818 | mntput(mnt: cache->mnt); |
819 | put_cred(cred: cache->cache_cred); |
820 | |
821 | kfree(objp: cache->rootdirname); |
822 | kfree(objp: cache->secctx); |
823 | kfree(objp: cache->tag); |
824 | |
825 | _leave("" ); |
826 | } |
827 | |