1// SPDX-License-Identifier: GPL-2.0-only
2/*
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(objp: pde->data);
41 if (pde->name != pde->inline_name)
42 kfree(objp: pde->name);
43 kmem_cache_free(s: proc_dir_entry_cache, objp: 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(name: de->name, de: this, len: 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(node: &de->subdir_node, parent, rb_link: new);
114 rb_insert_color(&de->subdir_node, root);
115 return true;
116}
117
118static int proc_notify_change(struct mnt_idmap *idmap,
119 struct dentry *dentry, struct iattr *iattr)
120{
121 struct inode *inode = d_inode(dentry);
122 struct proc_dir_entry *de = PDE(inode);
123 int error;
124
125 error = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
126 if (error)
127 return error;
128
129 setattr_copy(&nop_mnt_idmap, inode, attr: iattr);
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(struct mnt_idmap *idmap,
137 const struct path *path, struct kstat *stat,
138 u32 request_mask, unsigned int query_flags)
139{
140 struct inode *inode = d_inode(dentry: path->dentry);
141 struct proc_dir_entry *de = PDE(inode);
142 if (de) {
143 nlink_t nlink = READ_ONCE(de->nlink);
144 if (nlink > 0) {
145 set_nlink(inode, nlink);
146 }
147 }
148
149 generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
150 return 0;
151}
152
153static const struct inode_operations proc_file_inode_operations = {
154 .setattr = proc_notify_change,
155};
156
157/*
158 * This function parses a name such as "tty/driver/serial", and
159 * returns the struct proc_dir_entry for "/proc/tty/driver", and
160 * returns "serial" in residual.
161 */
162static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
163 const char **residual)
164{
165 const char *cp = name, *next;
166 struct proc_dir_entry *de;
167
168 de = *ret ?: &proc_root;
169 while ((next = strchr(cp, '/')) != NULL) {
170 de = pde_subdir_find(dir: de, name: cp, len: next - cp);
171 if (!de) {
172 WARN(1, "name '%s'\n", name);
173 return -ENOENT;
174 }
175 cp = next + 1;
176 }
177 *residual = cp;
178 *ret = de;
179 return 0;
180}
181
182static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
183 const char **residual)
184{
185 int rv;
186
187 read_lock(&proc_subdir_lock);
188 rv = __xlate_proc_name(name, ret, residual);
189 read_unlock(&proc_subdir_lock);
190 return rv;
191}
192
193static DEFINE_IDA(proc_inum_ida);
194
195#define PROC_DYNAMIC_FIRST 0xF0000000U
196
197/*
198 * Return an inode number between PROC_DYNAMIC_FIRST and
199 * 0xffffffff, or zero on failure.
200 */
201int proc_alloc_inum(unsigned int *inum)
202{
203 int i;
204
205 i = ida_alloc_max(ida: &proc_inum_ida, UINT_MAX - PROC_DYNAMIC_FIRST,
206 GFP_KERNEL);
207 if (i < 0)
208 return i;
209
210 *inum = PROC_DYNAMIC_FIRST + (unsigned int)i;
211 return 0;
212}
213
214void proc_free_inum(unsigned int inum)
215{
216 ida_free(&proc_inum_ida, id: inum - PROC_DYNAMIC_FIRST);
217}
218
219static int proc_misc_d_revalidate(struct inode *dir, const struct qstr *name,
220 struct dentry *dentry, unsigned int flags)
221{
222 if (flags & LOOKUP_RCU)
223 return -ECHILD;
224
225 if (atomic_read(v: &PDE(inode: d_inode(dentry))->in_use) < 0)
226 return 0; /* revalidate */
227 return 1;
228}
229
230static int proc_misc_d_delete(const struct dentry *dentry)
231{
232 return atomic_read(v: &PDE(inode: d_inode(dentry))->in_use) < 0;
233}
234
235static const struct dentry_operations proc_misc_dentry_ops = {
236 .d_revalidate = proc_misc_d_revalidate,
237 .d_delete = proc_misc_d_delete,
238};
239
240/*
241 * Don't create negative dentries here, return -ENOENT by hand
242 * instead.
243 */
244struct dentry *proc_lookup_de(struct inode *dir, struct dentry *dentry,
245 struct proc_dir_entry *de)
246{
247 struct inode *inode;
248
249 read_lock(&proc_subdir_lock);
250 de = pde_subdir_find(dir: de, name: dentry->d_name.name, len: dentry->d_name.len);
251 if (de) {
252 pde_get(pde: de);
253 read_unlock(&proc_subdir_lock);
254 inode = proc_get_inode(dir->i_sb, de);
255 if (!inode)
256 return ERR_PTR(error: -ENOMEM);
257 if (de->flags & PROC_ENTRY_FORCE_LOOKUP)
258 return d_splice_alias_ops(inode, dentry,
259 &proc_net_dentry_ops);
260 return d_splice_alias_ops(inode, dentry,
261 &proc_misc_dentry_ops);
262 }
263 read_unlock(&proc_subdir_lock);
264 return ERR_PTR(error: -ENOENT);
265}
266
267struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
268 unsigned int flags)
269{
270 struct proc_fs_info *fs_info = proc_sb_info(sb: dir->i_sb);
271
272 if (fs_info->pidonly == PROC_PIDONLY_ON)
273 return ERR_PTR(error: -ENOENT);
274
275 return proc_lookup_de(dir, dentry, de: PDE(inode: dir));
276}
277
278/*
279 * This returns non-zero if at EOF, so that the /proc
280 * root directory can use this and check if it should
281 * continue with the <pid> entries..
282 *
283 * Note that the VFS-layer doesn't care about the return
284 * value of the readdir() call, as long as it's non-negative
285 * for success..
286 */
287int proc_readdir_de(struct file *file, struct dir_context *ctx,
288 struct proc_dir_entry *de)
289{
290 int i;
291
292 if (!dir_emit_dots(file, ctx))
293 return 0;
294
295 i = ctx->pos - 2;
296 read_lock(&proc_subdir_lock);
297 de = pde_subdir_first(dir: de);
298 for (;;) {
299 if (!de) {
300 read_unlock(&proc_subdir_lock);
301 return 0;
302 }
303 if (!i)
304 break;
305 de = pde_subdir_next(dir: de);
306 i--;
307 }
308
309 do {
310 struct proc_dir_entry *next;
311 pde_get(pde: de);
312 read_unlock(&proc_subdir_lock);
313 if (!dir_emit(ctx, name: de->name, namelen: de->namelen,
314 ino: de->low_ino, type: de->mode >> 12)) {
315 pde_put(de);
316 return 0;
317 }
318 ctx->pos++;
319 read_lock(&proc_subdir_lock);
320 next = pde_subdir_next(dir: de);
321 pde_put(de);
322 de = next;
323 } while (de);
324 read_unlock(&proc_subdir_lock);
325 return 1;
326}
327
328int proc_readdir(struct file *file, struct dir_context *ctx)
329{
330 struct inode *inode = file_inode(f: file);
331 struct proc_fs_info *fs_info = proc_sb_info(sb: inode->i_sb);
332
333 if (fs_info->pidonly == PROC_PIDONLY_ON)
334 return 1;
335
336 return proc_readdir_de(file, ctx, de: PDE(inode));
337}
338
339/*
340 * These are the generic /proc directory operations. They
341 * use the in-memory "struct proc_dir_entry" tree to parse
342 * the /proc directory.
343 */
344static const struct file_operations proc_dir_operations = {
345 .llseek = generic_file_llseek,
346 .read = generic_read_dir,
347 .iterate_shared = proc_readdir,
348};
349
350static int proc_net_d_revalidate(struct inode *dir, const struct qstr *name,
351 struct dentry *dentry, unsigned int flags)
352{
353 return 0;
354}
355
356const struct dentry_operations proc_net_dentry_ops = {
357 .d_revalidate = proc_net_d_revalidate,
358 .d_delete = always_delete_dentry,
359};
360
361/*
362 * proc directories can do almost nothing..
363 */
364static const struct inode_operations proc_dir_inode_operations = {
365 .lookup = proc_lookup,
366 .getattr = proc_getattr,
367 .setattr = proc_notify_change,
368};
369
370static void pde_set_flags(struct proc_dir_entry *pde)
371{
372 const struct proc_ops *proc_ops = pde->proc_ops;
373
374 if (!proc_ops)
375 return;
376
377 if (proc_ops->proc_flags & PROC_ENTRY_PERMANENT)
378 pde->flags |= PROC_ENTRY_PERMANENT;
379 if (proc_ops->proc_read_iter)
380 pde->flags |= PROC_ENTRY_proc_read_iter;
381#ifdef CONFIG_COMPAT
382 if (proc_ops->proc_compat_ioctl)
383 pde->flags |= PROC_ENTRY_proc_compat_ioctl;
384#endif
385 if (proc_ops->proc_lseek)
386 pde->flags |= PROC_ENTRY_proc_lseek;
387}
388
389/* returns the registered entry, or frees dp and returns NULL on failure */
390struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
391 struct proc_dir_entry *dp)
392{
393 if (proc_alloc_inum(inum: &dp->low_ino))
394 goto out_free_entry;
395
396 if (!S_ISDIR(dp->mode))
397 pde_set_flags(pde: dp);
398
399 write_lock(&proc_subdir_lock);
400 dp->parent = dir;
401 if (pde_subdir_insert(dir, de: dp) == false) {
402 WARN(1, "proc_dir_entry '%s/%s' already registered\n",
403 dir->name, dp->name);
404 write_unlock(&proc_subdir_lock);
405 goto out_free_inum;
406 }
407 dir->nlink++;
408 write_unlock(&proc_subdir_lock);
409
410 return dp;
411out_free_inum:
412 proc_free_inum(inum: dp->low_ino);
413out_free_entry:
414 pde_free(pde: dp);
415 return NULL;
416}
417
418static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
419 const char *name,
420 umode_t mode,
421 nlink_t nlink)
422{
423 struct proc_dir_entry *ent = NULL;
424 const char *fn;
425 struct qstr qstr;
426
427 if (xlate_proc_name(name, ret: parent, residual: &fn) != 0)
428 goto out;
429 qstr.name = fn;
430 qstr.len = strlen(fn);
431 if (qstr.len == 0 || qstr.len >= 256) {
432 WARN(1, "name len %u\n", qstr.len);
433 return NULL;
434 }
435 if (qstr.len == 1 && fn[0] == '.') {
436 WARN(1, "name '.'\n");
437 return NULL;
438 }
439 if (qstr.len == 2 && fn[0] == '.' && fn[1] == '.') {
440 WARN(1, "name '..'\n");
441 return NULL;
442 }
443 if (*parent == &proc_root && name_to_int(qstr: &qstr) != ~0U) {
444 WARN(1, "create '/proc/%s' by hand\n", qstr.name);
445 return NULL;
446 }
447 if (is_empty_pde(pde: *parent)) {
448 WARN(1, "attempt to add to permanently empty directory");
449 return NULL;
450 }
451
452 ent = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL);
453 if (!ent)
454 goto out;
455
456 if (qstr.len + 1 <= SIZEOF_PDE_INLINE_NAME) {
457 ent->name = ent->inline_name;
458 } else {
459 ent->name = kmalloc(qstr.len + 1, GFP_KERNEL);
460 if (!ent->name) {
461 pde_free(pde: ent);
462 return NULL;
463 }
464 }
465
466 memcpy(to: ent->name, from: fn, len: qstr.len + 1);
467 ent->namelen = qstr.len;
468 ent->mode = mode;
469 ent->nlink = nlink;
470 ent->subdir = RB_ROOT;
471 refcount_set(r: &ent->refcnt, n: 1);
472 spin_lock_init(&ent->pde_unload_lock);
473 INIT_LIST_HEAD(list: &ent->pde_openers);
474 proc_set_user(ent, (*parent)->uid, (*parent)->gid);
475
476 /* Revalidate everything under /proc/${pid}/net */
477 if ((*parent)->flags & PROC_ENTRY_FORCE_LOOKUP)
478 pde_force_lookup(pde: ent);
479
480out:
481 return ent;
482}
483
484struct proc_dir_entry *proc_symlink(const char *name,
485 struct proc_dir_entry *parent, const char *dest)
486{
487 struct proc_dir_entry *ent;
488
489 ent = __proc_create(parent: &parent, name,
490 mode: (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),nlink: 1);
491
492 if (ent) {
493 ent->size = strlen(dest);
494 ent->data = kmemdup(dest, ent->size + 1, GFP_KERNEL);
495 if (ent->data) {
496 ent->proc_iops = &proc_link_inode_operations;
497 ent = proc_register(dir: parent, dp: ent);
498 } else {
499 pde_free(pde: ent);
500 ent = NULL;
501 }
502 }
503 return ent;
504}
505EXPORT_SYMBOL(proc_symlink);
506
507struct proc_dir_entry *_proc_mkdir(const char *name, umode_t mode,
508 struct proc_dir_entry *parent, void *data, bool force_lookup)
509{
510 struct proc_dir_entry *ent;
511
512 if (mode == 0)
513 mode = S_IRUGO | S_IXUGO;
514
515 ent = __proc_create(parent: &parent, name, S_IFDIR | mode, nlink: 2);
516 if (ent) {
517 ent->data = data;
518 ent->proc_dir_ops = &proc_dir_operations;
519 ent->proc_iops = &proc_dir_inode_operations;
520 if (force_lookup) {
521 pde_force_lookup(pde: ent);
522 }
523 ent = proc_register(dir: parent, dp: ent);
524 }
525 return ent;
526}
527EXPORT_SYMBOL_GPL(_proc_mkdir);
528
529struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
530 struct proc_dir_entry *parent, void *data)
531{
532 return _proc_mkdir(name, mode, parent, data, false);
533}
534EXPORT_SYMBOL_GPL(proc_mkdir_data);
535
536struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
537 struct proc_dir_entry *parent)
538{
539 return proc_mkdir_data(name, mode, parent, NULL);
540}
541EXPORT_SYMBOL(proc_mkdir_mode);
542
543struct proc_dir_entry *proc_mkdir(const char *name,
544 struct proc_dir_entry *parent)
545{
546 return proc_mkdir_data(name, 0, parent, NULL);
547}
548EXPORT_SYMBOL(proc_mkdir);
549
550struct proc_dir_entry *proc_create_mount_point(const char *name)
551{
552 umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO;
553 struct proc_dir_entry *ent, *parent = NULL;
554
555 ent = __proc_create(parent: &parent, name, mode, nlink: 2);
556 if (ent) {
557 ent->data = NULL;
558 ent->proc_dir_ops = NULL;
559 ent->proc_iops = NULL;
560 ent = proc_register(dir: parent, dp: ent);
561 }
562 return ent;
563}
564EXPORT_SYMBOL(proc_create_mount_point);
565
566struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
567 struct proc_dir_entry **parent, void *data)
568{
569 struct proc_dir_entry *p;
570
571 if ((mode & S_IFMT) == 0)
572 mode |= S_IFREG;
573 if ((mode & S_IALLUGO) == 0)
574 mode |= S_IRUGO;
575 if (WARN_ON_ONCE(!S_ISREG(mode)))
576 return NULL;
577
578 p = __proc_create(parent, name, mode, nlink: 1);
579 if (p) {
580 p->proc_iops = &proc_file_inode_operations;
581 p->data = data;
582 }
583 return p;
584}
585
586struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
587 struct proc_dir_entry *parent,
588 const struct proc_ops *proc_ops, void *data)
589{
590 struct proc_dir_entry *p;
591
592 p = proc_create_reg(name, mode, parent: &parent, data);
593 if (!p)
594 return NULL;
595 p->proc_ops = proc_ops;
596 return proc_register(dir: parent, dp: p);
597}
598EXPORT_SYMBOL(proc_create_data);
599
600struct proc_dir_entry *proc_create(const char *name, umode_t mode,
601 struct proc_dir_entry *parent,
602 const struct proc_ops *proc_ops)
603{
604 return proc_create_data(name, mode, parent, proc_ops, NULL);
605}
606EXPORT_SYMBOL(proc_create);
607
608static int proc_seq_open(struct inode *inode, struct file *file)
609{
610 struct proc_dir_entry *de = PDE(inode);
611
612 if (de->state_size)
613 return seq_open_private(file, de->seq_ops, de->state_size);
614 return seq_open(file, de->seq_ops);
615}
616
617static int proc_seq_release(struct inode *inode, struct file *file)
618{
619 struct proc_dir_entry *de = PDE(inode);
620
621 if (de->state_size)
622 return seq_release_private(inode, file);
623 return seq_release(inode, file);
624}
625
626static const struct proc_ops proc_seq_ops = {
627 /* not permanent -- can call into arbitrary seq_operations */
628 .proc_open = proc_seq_open,
629 .proc_read_iter = seq_read_iter,
630 .proc_lseek = seq_lseek,
631 .proc_release = proc_seq_release,
632};
633
634struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode,
635 struct proc_dir_entry *parent, const struct seq_operations *ops,
636 unsigned int state_size, void *data)
637{
638 struct proc_dir_entry *p;
639
640 p = proc_create_reg(name, mode, parent: &parent, data);
641 if (!p)
642 return NULL;
643 p->proc_ops = &proc_seq_ops;
644 p->seq_ops = ops;
645 p->state_size = state_size;
646 return proc_register(dir: parent, dp: p);
647}
648EXPORT_SYMBOL(proc_create_seq_private);
649
650static int proc_single_open(struct inode *inode, struct file *file)
651{
652 struct proc_dir_entry *de = PDE(inode);
653
654 return single_open(file, de->single_show, de->data);
655}
656
657static const struct proc_ops proc_single_ops = {
658 /* not permanent -- can call into arbitrary ->single_show */
659 .proc_open = proc_single_open,
660 .proc_read_iter = seq_read_iter,
661 .proc_lseek = seq_lseek,
662 .proc_release = single_release,
663};
664
665struct proc_dir_entry *proc_create_single_data(const char *name, umode_t mode,
666 struct proc_dir_entry *parent,
667 int (*show)(struct seq_file *, void *), void *data)
668{
669 struct proc_dir_entry *p;
670
671 p = proc_create_reg(name, mode, parent: &parent, data);
672 if (!p)
673 return NULL;
674 p->proc_ops = &proc_single_ops;
675 p->single_show = show;
676 return proc_register(dir: parent, dp: p);
677}
678EXPORT_SYMBOL(proc_create_single_data);
679
680void proc_set_size(struct proc_dir_entry *de, loff_t size)
681{
682 de->size = size;
683}
684EXPORT_SYMBOL(proc_set_size);
685
686void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
687{
688 de->uid = uid;
689 de->gid = gid;
690}
691EXPORT_SYMBOL(proc_set_user);
692
693void pde_put(struct proc_dir_entry *pde)
694{
695 if (refcount_dec_and_test(r: &pde->refcnt)) {
696 proc_free_inum(inum: pde->low_ino);
697 pde_free(pde);
698 }
699}
700
701/*
702 * Remove a /proc entry and free it if it's not currently in use.
703 */
704void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
705{
706 struct proc_dir_entry *de = NULL;
707 const char *fn = name;
708 unsigned int len;
709
710 write_lock(&proc_subdir_lock);
711 if (__xlate_proc_name(name, ret: &parent, residual: &fn) != 0) {
712 write_unlock(&proc_subdir_lock);
713 return;
714 }
715 len = strlen(fn);
716
717 de = pde_subdir_find(dir: parent, name: fn, len);
718 if (de) {
719 if (unlikely(pde_is_permanent(de))) {
720 WARN(1, "removing permanent /proc entry '%s'", de->name);
721 de = NULL;
722 } else {
723 rb_erase(&de->subdir_node, &parent->subdir);
724 if (S_ISDIR(de->mode))
725 parent->nlink--;
726 }
727 }
728 write_unlock(&proc_subdir_lock);
729 if (!de) {
730 WARN(1, "name '%s'\n", name);
731 return;
732 }
733
734 proc_entry_rundown(de);
735
736 WARN(pde_subdir_first(de),
737 "%s: removing non-empty directory '%s/%s', leaking at least '%s'\n",
738 __func__, de->parent->name, de->name, pde_subdir_first(de)->name);
739 pde_put(pde: de);
740}
741EXPORT_SYMBOL(remove_proc_entry);
742
743int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
744{
745 struct proc_dir_entry *root = NULL, *de, *next;
746 const char *fn = name;
747 unsigned int len;
748
749 write_lock(&proc_subdir_lock);
750 if (__xlate_proc_name(name, ret: &parent, residual: &fn) != 0) {
751 write_unlock(&proc_subdir_lock);
752 return -ENOENT;
753 }
754 len = strlen(fn);
755
756 root = pde_subdir_find(dir: parent, name: fn, len);
757 if (!root) {
758 write_unlock(&proc_subdir_lock);
759 return -ENOENT;
760 }
761 if (unlikely(pde_is_permanent(root))) {
762 write_unlock(&proc_subdir_lock);
763 WARN(1, "removing permanent /proc entry '%s/%s'",
764 root->parent->name, root->name);
765 return -EINVAL;
766 }
767 rb_erase(&root->subdir_node, &parent->subdir);
768
769 de = root;
770 while (1) {
771 next = pde_subdir_first(dir: de);
772 if (next) {
773 if (unlikely(pde_is_permanent(next))) {
774 write_unlock(&proc_subdir_lock);
775 WARN(1, "removing permanent /proc entry '%s/%s'",
776 next->parent->name, next->name);
777 return -EINVAL;
778 }
779 rb_erase(&next->subdir_node, &de->subdir);
780 de = next;
781 continue;
782 }
783 next = de->parent;
784 if (S_ISDIR(de->mode))
785 next->nlink--;
786 write_unlock(&proc_subdir_lock);
787
788 proc_entry_rundown(de);
789 if (de == root)
790 break;
791 pde_put(pde: de);
792
793 write_lock(&proc_subdir_lock);
794 de = next;
795 }
796 pde_put(pde: root);
797 return 0;
798}
799EXPORT_SYMBOL(remove_proc_subtree);
800
801void *proc_get_parent_data(const struct inode *inode)
802{
803 struct proc_dir_entry *de = PDE(inode);
804 return de->parent->data;
805}
806EXPORT_SYMBOL_GPL(proc_get_parent_data);
807
808void proc_remove(struct proc_dir_entry *de)
809{
810 if (de)
811 remove_proc_subtree(de->name, de->parent);
812}
813EXPORT_SYMBOL(proc_remove);
814
815/*
816 * Pull a user buffer into memory and pass it to the file's write handler if
817 * one is supplied. The ->write() method is permitted to modify the
818 * kernel-side buffer.
819 */
820ssize_t proc_simple_write(struct file *f, const char __user *ubuf, size_t size,
821 loff_t *_pos)
822{
823 struct proc_dir_entry *pde = PDE(inode: file_inode(f));
824 char *buf;
825 int ret;
826
827 if (!pde->write)
828 return -EACCES;
829 if (size == 0 || size > PAGE_SIZE - 1)
830 return -EINVAL;
831 buf = memdup_user_nul(ubuf, size);
832 if (IS_ERR(ptr: buf))
833 return PTR_ERR(ptr: buf);
834 ret = pde->write(f, buf, size);
835 kfree(objp: buf);
836 return ret == 0 ? size : ret;
837}
838