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David Brazdil0f672f62019-12-10 10:32:29 +00001// SPDX-License-Identifier: GPL-2.0-only
Andrew Scullb4b6d4a2019-01-02 15:54:55 +00002/*
3 * proc/fs/generic.c --- generic routines for the proc-fs
4 *
5 * This file contains generic proc-fs routines for handling
6 * directories and files.
7 *
8 * Copyright (C) 1991, 1992 Linus Torvalds.
9 * Copyright (C) 1997 Theodore Ts'o
10 */
11
12#include <linux/cache.h>
13#include <linux/errno.h>
14#include <linux/time.h>
15#include <linux/proc_fs.h>
16#include <linux/stat.h>
17#include <linux/mm.h>
18#include <linux/module.h>
19#include <linux/namei.h>
20#include <linux/slab.h>
21#include <linux/printk.h>
22#include <linux/mount.h>
23#include <linux/init.h>
24#include <linux/idr.h>
25#include <linux/bitops.h>
26#include <linux/spinlock.h>
27#include <linux/completion.h>
28#include <linux/uaccess.h>
29#include <linux/seq_file.h>
30
31#include "internal.h"
32
33static DEFINE_RWLOCK(proc_subdir_lock);
34
35struct kmem_cache *proc_dir_entry_cache __ro_after_init;
36
37void pde_free(struct proc_dir_entry *pde)
38{
39 if (S_ISLNK(pde->mode))
40 kfree(pde->data);
41 if (pde->name != pde->inline_name)
42 kfree(pde->name);
43 kmem_cache_free(proc_dir_entry_cache, pde);
44}
45
46static int proc_match(const char *name, struct proc_dir_entry *de, unsigned int len)
47{
48 if (len < de->namelen)
49 return -1;
50 if (len > de->namelen)
51 return 1;
52
53 return memcmp(name, de->name, len);
54}
55
56static struct proc_dir_entry *pde_subdir_first(struct proc_dir_entry *dir)
57{
58 return rb_entry_safe(rb_first(&dir->subdir), struct proc_dir_entry,
59 subdir_node);
60}
61
62static struct proc_dir_entry *pde_subdir_next(struct proc_dir_entry *dir)
63{
64 return rb_entry_safe(rb_next(&dir->subdir_node), struct proc_dir_entry,
65 subdir_node);
66}
67
68static struct proc_dir_entry *pde_subdir_find(struct proc_dir_entry *dir,
69 const char *name,
70 unsigned int len)
71{
72 struct rb_node *node = dir->subdir.rb_node;
73
74 while (node) {
75 struct proc_dir_entry *de = rb_entry(node,
76 struct proc_dir_entry,
77 subdir_node);
78 int result = proc_match(name, de, len);
79
80 if (result < 0)
81 node = node->rb_left;
82 else if (result > 0)
83 node = node->rb_right;
84 else
85 return de;
86 }
87 return NULL;
88}
89
90static bool pde_subdir_insert(struct proc_dir_entry *dir,
91 struct proc_dir_entry *de)
92{
93 struct rb_root *root = &dir->subdir;
94 struct rb_node **new = &root->rb_node, *parent = NULL;
95
96 /* Figure out where to put new node */
97 while (*new) {
98 struct proc_dir_entry *this = rb_entry(*new,
99 struct proc_dir_entry,
100 subdir_node);
101 int result = proc_match(de->name, this, de->namelen);
102
103 parent = *new;
104 if (result < 0)
105 new = &(*new)->rb_left;
106 else if (result > 0)
107 new = &(*new)->rb_right;
108 else
109 return false;
110 }
111
112 /* Add new node and rebalance tree. */
113 rb_link_node(&de->subdir_node, parent, new);
114 rb_insert_color(&de->subdir_node, root);
115 return true;
116}
117
118static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
119{
120 struct inode *inode = d_inode(dentry);
121 struct proc_dir_entry *de = PDE(inode);
122 int error;
123
124 error = setattr_prepare(dentry, iattr);
125 if (error)
126 return error;
127
128 setattr_copy(inode, iattr);
129 mark_inode_dirty(inode);
130
131 proc_set_user(de, inode->i_uid, inode->i_gid);
132 de->mode = inode->i_mode;
133 return 0;
134}
135
136static int proc_getattr(const struct path *path, struct kstat *stat,
137 u32 request_mask, unsigned int query_flags)
138{
139 struct inode *inode = d_inode(path->dentry);
140 struct proc_dir_entry *de = PDE(inode);
Olivier Deprez0e641232021-09-23 10:07:05 +0200141 if (de) {
142 nlink_t nlink = READ_ONCE(de->nlink);
143 if (nlink > 0) {
144 set_nlink(inode, nlink);
145 }
146 }
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000147
148 generic_fillattr(inode, stat);
149 return 0;
150}
151
152static const struct inode_operations proc_file_inode_operations = {
153 .setattr = proc_notify_change,
154};
155
156/*
157 * This function parses a name such as "tty/driver/serial", and
158 * returns the struct proc_dir_entry for "/proc/tty/driver", and
159 * returns "serial" in residual.
160 */
161static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
162 const char **residual)
163{
164 const char *cp = name, *next;
165 struct proc_dir_entry *de;
166 unsigned int len;
167
168 de = *ret;
169 if (!de)
170 de = &proc_root;
171
172 while (1) {
173 next = strchr(cp, '/');
174 if (!next)
175 break;
176
177 len = next - cp;
178 de = pde_subdir_find(de, cp, len);
179 if (!de) {
180 WARN(1, "name '%s'\n", name);
181 return -ENOENT;
182 }
183 cp += len + 1;
184 }
185 *residual = cp;
186 *ret = de;
187 return 0;
188}
189
190static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
191 const char **residual)
192{
193 int rv;
194
195 read_lock(&proc_subdir_lock);
196 rv = __xlate_proc_name(name, ret, residual);
197 read_unlock(&proc_subdir_lock);
198 return rv;
199}
200
201static DEFINE_IDA(proc_inum_ida);
202
203#define PROC_DYNAMIC_FIRST 0xF0000000U
204
205/*
206 * Return an inode number between PROC_DYNAMIC_FIRST and
207 * 0xffffffff, or zero on failure.
208 */
209int proc_alloc_inum(unsigned int *inum)
210{
211 int i;
212
213 i = ida_simple_get(&proc_inum_ida, 0, UINT_MAX - PROC_DYNAMIC_FIRST + 1,
214 GFP_KERNEL);
215 if (i < 0)
216 return i;
217
218 *inum = PROC_DYNAMIC_FIRST + (unsigned int)i;
219 return 0;
220}
221
222void proc_free_inum(unsigned int inum)
223{
224 ida_simple_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
225}
226
227static int proc_misc_d_revalidate(struct dentry *dentry, unsigned int flags)
228{
229 if (flags & LOOKUP_RCU)
230 return -ECHILD;
231
232 if (atomic_read(&PDE(d_inode(dentry))->in_use) < 0)
233 return 0; /* revalidate */
234 return 1;
235}
236
237static int proc_misc_d_delete(const struct dentry *dentry)
238{
239 return atomic_read(&PDE(d_inode(dentry))->in_use) < 0;
240}
241
242static const struct dentry_operations proc_misc_dentry_ops = {
243 .d_revalidate = proc_misc_d_revalidate,
244 .d_delete = proc_misc_d_delete,
245};
246
247/*
248 * Don't create negative dentries here, return -ENOENT by hand
249 * instead.
250 */
251struct dentry *proc_lookup_de(struct inode *dir, struct dentry *dentry,
252 struct proc_dir_entry *de)
253{
254 struct inode *inode;
255
256 read_lock(&proc_subdir_lock);
257 de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len);
258 if (de) {
259 pde_get(de);
260 read_unlock(&proc_subdir_lock);
261 inode = proc_get_inode(dir->i_sb, de);
262 if (!inode)
263 return ERR_PTR(-ENOMEM);
David Brazdil0f672f62019-12-10 10:32:29 +0000264 d_set_d_op(dentry, de->proc_dops);
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000265 return d_splice_alias(inode, dentry);
266 }
267 read_unlock(&proc_subdir_lock);
268 return ERR_PTR(-ENOENT);
269}
270
271struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
272 unsigned int flags)
273{
274 return proc_lookup_de(dir, dentry, PDE(dir));
275}
276
277/*
278 * This returns non-zero if at EOF, so that the /proc
279 * root directory can use this and check if it should
280 * continue with the <pid> entries..
281 *
282 * Note that the VFS-layer doesn't care about the return
283 * value of the readdir() call, as long as it's non-negative
284 * for success..
285 */
286int proc_readdir_de(struct file *file, struct dir_context *ctx,
287 struct proc_dir_entry *de)
288{
289 int i;
290
291 if (!dir_emit_dots(file, ctx))
292 return 0;
293
294 i = ctx->pos - 2;
295 read_lock(&proc_subdir_lock);
296 de = pde_subdir_first(de);
297 for (;;) {
298 if (!de) {
299 read_unlock(&proc_subdir_lock);
300 return 0;
301 }
302 if (!i)
303 break;
304 de = pde_subdir_next(de);
305 i--;
306 }
307
308 do {
309 struct proc_dir_entry *next;
310 pde_get(de);
311 read_unlock(&proc_subdir_lock);
312 if (!dir_emit(ctx, de->name, de->namelen,
313 de->low_ino, de->mode >> 12)) {
314 pde_put(de);
315 return 0;
316 }
317 ctx->pos++;
318 read_lock(&proc_subdir_lock);
319 next = pde_subdir_next(de);
320 pde_put(de);
321 de = next;
322 } while (de);
323 read_unlock(&proc_subdir_lock);
324 return 1;
325}
326
327int proc_readdir(struct file *file, struct dir_context *ctx)
328{
329 struct inode *inode = file_inode(file);
330
331 return proc_readdir_de(file, ctx, PDE(inode));
332}
333
334/*
335 * These are the generic /proc directory operations. They
336 * use the in-memory "struct proc_dir_entry" tree to parse
337 * the /proc directory.
338 */
339static const struct file_operations proc_dir_operations = {
340 .llseek = generic_file_llseek,
341 .read = generic_read_dir,
342 .iterate_shared = proc_readdir,
343};
344
Olivier Deprez0e641232021-09-23 10:07:05 +0200345static int proc_net_d_revalidate(struct dentry *dentry, unsigned int flags)
346{
347 return 0;
348}
349
350const struct dentry_operations proc_net_dentry_ops = {
351 .d_revalidate = proc_net_d_revalidate,
352 .d_delete = always_delete_dentry,
353};
354
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000355/*
356 * proc directories can do almost nothing..
357 */
358static const struct inode_operations proc_dir_inode_operations = {
359 .lookup = proc_lookup,
360 .getattr = proc_getattr,
361 .setattr = proc_notify_change,
362};
363
364/* returns the registered entry, or frees dp and returns NULL on failure */
365struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
366 struct proc_dir_entry *dp)
367{
368 if (proc_alloc_inum(&dp->low_ino))
369 goto out_free_entry;
370
371 write_lock(&proc_subdir_lock);
372 dp->parent = dir;
373 if (pde_subdir_insert(dir, dp) == false) {
374 WARN(1, "proc_dir_entry '%s/%s' already registered\n",
375 dir->name, dp->name);
376 write_unlock(&proc_subdir_lock);
377 goto out_free_inum;
378 }
Olivier Deprez0e641232021-09-23 10:07:05 +0200379 dir->nlink++;
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000380 write_unlock(&proc_subdir_lock);
381
382 return dp;
383out_free_inum:
384 proc_free_inum(dp->low_ino);
385out_free_entry:
386 pde_free(dp);
387 return NULL;
388}
389
390static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
391 const char *name,
392 umode_t mode,
393 nlink_t nlink)
394{
395 struct proc_dir_entry *ent = NULL;
396 const char *fn;
397 struct qstr qstr;
398
399 if (xlate_proc_name(name, parent, &fn) != 0)
400 goto out;
401 qstr.name = fn;
402 qstr.len = strlen(fn);
403 if (qstr.len == 0 || qstr.len >= 256) {
404 WARN(1, "name len %u\n", qstr.len);
405 return NULL;
406 }
407 if (qstr.len == 1 && fn[0] == '.') {
408 WARN(1, "name '.'\n");
409 return NULL;
410 }
411 if (qstr.len == 2 && fn[0] == '.' && fn[1] == '.') {
412 WARN(1, "name '..'\n");
413 return NULL;
414 }
415 if (*parent == &proc_root && name_to_int(&qstr) != ~0U) {
416 WARN(1, "create '/proc/%s' by hand\n", qstr.name);
417 return NULL;
418 }
419 if (is_empty_pde(*parent)) {
420 WARN(1, "attempt to add to permanently empty directory");
421 return NULL;
422 }
423
424 ent = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL);
425 if (!ent)
426 goto out;
427
428 if (qstr.len + 1 <= SIZEOF_PDE_INLINE_NAME) {
429 ent->name = ent->inline_name;
430 } else {
431 ent->name = kmalloc(qstr.len + 1, GFP_KERNEL);
432 if (!ent->name) {
433 pde_free(ent);
434 return NULL;
435 }
436 }
437
438 memcpy(ent->name, fn, qstr.len + 1);
439 ent->namelen = qstr.len;
440 ent->mode = mode;
441 ent->nlink = nlink;
442 ent->subdir = RB_ROOT;
443 refcount_set(&ent->refcnt, 1);
444 spin_lock_init(&ent->pde_unload_lock);
445 INIT_LIST_HEAD(&ent->pde_openers);
446 proc_set_user(ent, (*parent)->uid, (*parent)->gid);
447
David Brazdil0f672f62019-12-10 10:32:29 +0000448 ent->proc_dops = &proc_misc_dentry_ops;
449
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000450out:
451 return ent;
452}
453
454struct proc_dir_entry *proc_symlink(const char *name,
455 struct proc_dir_entry *parent, const char *dest)
456{
457 struct proc_dir_entry *ent;
458
459 ent = __proc_create(&parent, name,
460 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
461
462 if (ent) {
463 ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
464 if (ent->data) {
465 strcpy((char*)ent->data,dest);
466 ent->proc_iops = &proc_link_inode_operations;
467 ent = proc_register(parent, ent);
468 } else {
469 pde_free(ent);
470 ent = NULL;
471 }
472 }
473 return ent;
474}
475EXPORT_SYMBOL(proc_symlink);
476
Olivier Deprez0e641232021-09-23 10:07:05 +0200477struct proc_dir_entry *_proc_mkdir(const char *name, umode_t mode,
478 struct proc_dir_entry *parent, void *data, bool force_lookup)
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000479{
480 struct proc_dir_entry *ent;
481
482 if (mode == 0)
483 mode = S_IRUGO | S_IXUGO;
484
485 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
486 if (ent) {
487 ent->data = data;
488 ent->proc_fops = &proc_dir_operations;
489 ent->proc_iops = &proc_dir_inode_operations;
Olivier Deprez0e641232021-09-23 10:07:05 +0200490 if (force_lookup) {
491 pde_force_lookup(ent);
492 }
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000493 ent = proc_register(parent, ent);
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000494 }
495 return ent;
496}
Olivier Deprez0e641232021-09-23 10:07:05 +0200497EXPORT_SYMBOL_GPL(_proc_mkdir);
498
499struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
500 struct proc_dir_entry *parent, void *data)
501{
502 return _proc_mkdir(name, mode, parent, data, false);
503}
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000504EXPORT_SYMBOL_GPL(proc_mkdir_data);
505
506struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
507 struct proc_dir_entry *parent)
508{
509 return proc_mkdir_data(name, mode, parent, NULL);
510}
511EXPORT_SYMBOL(proc_mkdir_mode);
512
513struct proc_dir_entry *proc_mkdir(const char *name,
514 struct proc_dir_entry *parent)
515{
516 return proc_mkdir_data(name, 0, parent, NULL);
517}
518EXPORT_SYMBOL(proc_mkdir);
519
520struct proc_dir_entry *proc_create_mount_point(const char *name)
521{
522 umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO;
523 struct proc_dir_entry *ent, *parent = NULL;
524
525 ent = __proc_create(&parent, name, mode, 2);
526 if (ent) {
527 ent->data = NULL;
528 ent->proc_fops = NULL;
529 ent->proc_iops = NULL;
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000530 ent = proc_register(parent, ent);
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000531 }
532 return ent;
533}
534EXPORT_SYMBOL(proc_create_mount_point);
535
536struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
537 struct proc_dir_entry **parent, void *data)
538{
539 struct proc_dir_entry *p;
540
541 if ((mode & S_IFMT) == 0)
542 mode |= S_IFREG;
543 if ((mode & S_IALLUGO) == 0)
544 mode |= S_IRUGO;
545 if (WARN_ON_ONCE(!S_ISREG(mode)))
546 return NULL;
547
548 p = __proc_create(parent, name, mode, 1);
549 if (p) {
550 p->proc_iops = &proc_file_inode_operations;
551 p->data = data;
552 }
553 return p;
554}
555
556struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
557 struct proc_dir_entry *parent,
558 const struct file_operations *proc_fops, void *data)
559{
560 struct proc_dir_entry *p;
561
562 BUG_ON(proc_fops == NULL);
563
564 p = proc_create_reg(name, mode, &parent, data);
565 if (!p)
566 return NULL;
567 p->proc_fops = proc_fops;
568 return proc_register(parent, p);
569}
570EXPORT_SYMBOL(proc_create_data);
571
572struct proc_dir_entry *proc_create(const char *name, umode_t mode,
573 struct proc_dir_entry *parent,
574 const struct file_operations *proc_fops)
575{
576 return proc_create_data(name, mode, parent, proc_fops, NULL);
577}
578EXPORT_SYMBOL(proc_create);
579
580static int proc_seq_open(struct inode *inode, struct file *file)
581{
582 struct proc_dir_entry *de = PDE(inode);
583
584 if (de->state_size)
585 return seq_open_private(file, de->seq_ops, de->state_size);
586 return seq_open(file, de->seq_ops);
587}
588
589static int proc_seq_release(struct inode *inode, struct file *file)
590{
591 struct proc_dir_entry *de = PDE(inode);
592
593 if (de->state_size)
594 return seq_release_private(inode, file);
595 return seq_release(inode, file);
596}
597
598static const struct file_operations proc_seq_fops = {
599 .open = proc_seq_open,
600 .read = seq_read,
601 .llseek = seq_lseek,
602 .release = proc_seq_release,
603};
604
605struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode,
606 struct proc_dir_entry *parent, const struct seq_operations *ops,
607 unsigned int state_size, void *data)
608{
609 struct proc_dir_entry *p;
610
611 p = proc_create_reg(name, mode, &parent, data);
612 if (!p)
613 return NULL;
614 p->proc_fops = &proc_seq_fops;
615 p->seq_ops = ops;
616 p->state_size = state_size;
617 return proc_register(parent, p);
618}
619EXPORT_SYMBOL(proc_create_seq_private);
620
621static int proc_single_open(struct inode *inode, struct file *file)
622{
623 struct proc_dir_entry *de = PDE(inode);
624
625 return single_open(file, de->single_show, de->data);
626}
627
628static const struct file_operations proc_single_fops = {
629 .open = proc_single_open,
630 .read = seq_read,
631 .llseek = seq_lseek,
632 .release = single_release,
633};
634
635struct proc_dir_entry *proc_create_single_data(const char *name, umode_t mode,
636 struct proc_dir_entry *parent,
637 int (*show)(struct seq_file *, void *), void *data)
638{
639 struct proc_dir_entry *p;
640
641 p = proc_create_reg(name, mode, &parent, data);
642 if (!p)
643 return NULL;
644 p->proc_fops = &proc_single_fops;
645 p->single_show = show;
646 return proc_register(parent, p);
647}
648EXPORT_SYMBOL(proc_create_single_data);
649
650void proc_set_size(struct proc_dir_entry *de, loff_t size)
651{
652 de->size = size;
653}
654EXPORT_SYMBOL(proc_set_size);
655
656void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
657{
658 de->uid = uid;
659 de->gid = gid;
660}
661EXPORT_SYMBOL(proc_set_user);
662
663void pde_put(struct proc_dir_entry *pde)
664{
665 if (refcount_dec_and_test(&pde->refcnt)) {
666 proc_free_inum(pde->low_ino);
667 pde_free(pde);
668 }
669}
670
671/*
672 * Remove a /proc entry and free it if it's not currently in use.
673 */
674void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
675{
676 struct proc_dir_entry *de = NULL;
677 const char *fn = name;
678 unsigned int len;
679
680 write_lock(&proc_subdir_lock);
681 if (__xlate_proc_name(name, &parent, &fn) != 0) {
682 write_unlock(&proc_subdir_lock);
683 return;
684 }
685 len = strlen(fn);
686
687 de = pde_subdir_find(parent, fn, len);
Olivier Deprez0e641232021-09-23 10:07:05 +0200688 if (de) {
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000689 rb_erase(&de->subdir_node, &parent->subdir);
Olivier Deprez0e641232021-09-23 10:07:05 +0200690 if (S_ISDIR(de->mode)) {
691 parent->nlink--;
692 }
693 }
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000694 write_unlock(&proc_subdir_lock);
695 if (!de) {
696 WARN(1, "name '%s'\n", name);
697 return;
698 }
699
700 proc_entry_rundown(de);
701
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000702 WARN(pde_subdir_first(de),
703 "%s: removing non-empty directory '%s/%s', leaking at least '%s'\n",
704 __func__, de->parent->name, de->name, pde_subdir_first(de)->name);
705 pde_put(de);
706}
707EXPORT_SYMBOL(remove_proc_entry);
708
709int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
710{
711 struct proc_dir_entry *root = NULL, *de, *next;
712 const char *fn = name;
713 unsigned int len;
714
715 write_lock(&proc_subdir_lock);
716 if (__xlate_proc_name(name, &parent, &fn) != 0) {
717 write_unlock(&proc_subdir_lock);
718 return -ENOENT;
719 }
720 len = strlen(fn);
721
722 root = pde_subdir_find(parent, fn, len);
723 if (!root) {
724 write_unlock(&proc_subdir_lock);
725 return -ENOENT;
726 }
727 rb_erase(&root->subdir_node, &parent->subdir);
728
729 de = root;
730 while (1) {
731 next = pde_subdir_first(de);
732 if (next) {
733 rb_erase(&next->subdir_node, &de->subdir);
734 de = next;
735 continue;
736 }
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000737 next = de->parent;
738 if (S_ISDIR(de->mode))
739 next->nlink--;
Olivier Deprez0e641232021-09-23 10:07:05 +0200740 write_unlock(&proc_subdir_lock);
741
742 proc_entry_rundown(de);
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000743 if (de == root)
744 break;
745 pde_put(de);
746
747 write_lock(&proc_subdir_lock);
748 de = next;
749 }
750 pde_put(root);
751 return 0;
752}
753EXPORT_SYMBOL(remove_proc_subtree);
754
755void *proc_get_parent_data(const struct inode *inode)
756{
757 struct proc_dir_entry *de = PDE(inode);
758 return de->parent->data;
759}
760EXPORT_SYMBOL_GPL(proc_get_parent_data);
761
762void proc_remove(struct proc_dir_entry *de)
763{
764 if (de)
765 remove_proc_subtree(de->name, de->parent);
766}
767EXPORT_SYMBOL(proc_remove);
768
769void *PDE_DATA(const struct inode *inode)
770{
771 return __PDE_DATA(inode);
772}
773EXPORT_SYMBOL(PDE_DATA);
774
775/*
776 * Pull a user buffer into memory and pass it to the file's write handler if
777 * one is supplied. The ->write() method is permitted to modify the
778 * kernel-side buffer.
779 */
780ssize_t proc_simple_write(struct file *f, const char __user *ubuf, size_t size,
781 loff_t *_pos)
782{
783 struct proc_dir_entry *pde = PDE(file_inode(f));
784 char *buf;
785 int ret;
786
787 if (!pde->write)
788 return -EACCES;
789 if (size == 0 || size > PAGE_SIZE - 1)
790 return -EINVAL;
791 buf = memdup_user_nul(ubuf, size);
792 if (IS_ERR(buf))
793 return PTR_ERR(buf);
794 ret = pde->write(f, buf, size);
795 kfree(buf);
796 return ret == 0 ? size : ret;
797}