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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(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 if (S_ISDIR(de->mode))
116 dir->nlink++;
117 return true;
118}
119
120static int proc_setattr(const struct mnt_idmap *idmap, struct dentry *dentry,
121 struct iattr *iattr)
122{
123 struct inode *inode = d_inode(dentry);
124 struct proc_dir_entry *de = PDE(inode);
125 int error;
126
127 error = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
128 if (error)
129 return error;
130
131 setattr_copy(&nop_mnt_idmap, inode, iattr);
132
133 proc_set_user(de, inode->i_uid, inode->i_gid);
134 de->mode = inode->i_mode;
135 return 0;
136}
137
138static int proc_getattr(const struct mnt_idmap *idmap,
139 const struct path *path, struct kstat *stat,
140 u32 request_mask, unsigned int query_flags)
141{
142 struct inode *inode = d_inode(path->dentry);
143 struct proc_dir_entry *de = PDE(inode);
144 if (de) {
145 nlink_t nlink = READ_ONCE(de->nlink);
146 if (nlink > 0) {
147 set_nlink(inode, nlink);
148 }
149 }
150
151 generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
152 return 0;
153}
154
155static const struct inode_operations proc_file_inode_operations = {
156 .setattr = proc_setattr,
157};
158
159/*
160 * This function parses a name such as "tty/driver/serial", and
161 * returns the struct proc_dir_entry for "/proc/tty/driver", and
162 * returns "serial" in residual.
163 */
164static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
165 const char **residual)
166{
167 const char *cp = name, *next;
168 struct proc_dir_entry *de;
169
170 de = *ret ?: &proc_root;
171 while ((next = strchr(cp, '/')) != NULL) {
172 de = pde_subdir_find(de, cp, next - cp);
173 if (!de) {
174 WARN(1, "name '%s'\n", name);
175 return -ENOENT;
176 }
177 cp = next + 1;
178 }
179 *residual = cp;
180 *ret = de;
181 return 0;
182}
183
184static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
185 const char **residual)
186{
187 int rv;
188
189 read_lock(&proc_subdir_lock);
190 rv = __xlate_proc_name(name, ret, residual);
191 read_unlock(&proc_subdir_lock);
192 return rv;
193}
194
195static DEFINE_IDA(proc_inum_ida);
196
197#define PROC_DYNAMIC_FIRST 0xF0000000U
198
199/*
200 * Return an inode number between PROC_DYNAMIC_FIRST and
201 * 0xffffffff, or zero on failure.
202 */
203int proc_alloc_inum(unsigned int *inum)
204{
205 int i;
206
207 i = ida_alloc_max(&proc_inum_ida, UINT_MAX - PROC_DYNAMIC_FIRST,
208 GFP_KERNEL);
209 if (i < 0)
210 return i;
211
212 *inum = PROC_DYNAMIC_FIRST + (unsigned int)i;
213 return 0;
214}
215
216void proc_free_inum(unsigned int inum)
217{
218 ida_free(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
219}
220
221static int proc_misc_d_revalidate(struct inode *dir, const struct qstr *name,
222 struct dentry *dentry, unsigned int flags)
223{
224 if (flags & LOOKUP_RCU)
225 return -ECHILD;
226
227 if (atomic_read(&PDE(d_inode(dentry))->in_use) < 0)
228 return 0; /* revalidate */
229 return 1;
230}
231
232static int proc_misc_d_delete(const struct dentry *dentry)
233{
234 return atomic_read(&PDE(d_inode(dentry))->in_use) < 0;
235}
236
237static const struct dentry_operations proc_misc_dentry_ops = {
238 .d_revalidate = proc_misc_d_revalidate,
239 .d_delete = proc_misc_d_delete,
240};
241
242/*
243 * Don't create negative dentries here, return -ENOENT by hand
244 * instead.
245 */
246struct dentry *proc_lookup_de(struct inode *dir, struct dentry *dentry,
247 struct proc_dir_entry *de)
248{
249 struct inode *inode;
250
251 read_lock(&proc_subdir_lock);
252 de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len);
253 if (de) {
254 pde_get(de);
255 read_unlock(&proc_subdir_lock);
256 inode = proc_get_inode(dir->i_sb, de);
257 if (!inode)
258 return ERR_PTR(-ENOMEM);
259 if (de->flags & PROC_ENTRY_FORCE_LOOKUP)
260 return d_splice_alias_ops(inode, dentry,
261 &proc_net_dentry_ops);
262 return d_splice_alias_ops(inode, dentry,
263 &proc_misc_dentry_ops);
264 }
265 read_unlock(&proc_subdir_lock);
266 return ERR_PTR(-ENOENT);
267}
268
269struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
270 unsigned int flags)
271{
272 struct proc_fs_info *fs_info = proc_sb_info(dir->i_sb);
273
274 if (fs_info->pidonly == PROC_PIDONLY_ON)
275 return ERR_PTR(-ENOENT);
276
277 return proc_lookup_de(dir, dentry, PDE(dir));
278}
279
280/*
281 * This returns non-zero if at EOF, so that the /proc
282 * root directory can use this and check if it should
283 * continue with the <pid> entries..
284 *
285 * Note that the VFS-layer doesn't care about the return
286 * value of the readdir() call, as long as it's non-negative
287 * for success..
288 */
289int proc_readdir_de(struct file *file, struct dir_context *ctx,
290 struct proc_dir_entry *de)
291{
292 int i;
293
294 if (!dir_emit_dots(file, ctx))
295 return 0;
296
297 i = ctx->pos - 2;
298 read_lock(&proc_subdir_lock);
299 de = pde_subdir_first(de);
300 for (;;) {
301 if (!de) {
302 read_unlock(&proc_subdir_lock);
303 return 0;
304 }
305 if (!i)
306 break;
307 de = pde_subdir_next(de);
308 i--;
309 }
310
311 do {
312 struct proc_dir_entry *next;
313 pde_get(de);
314 read_unlock(&proc_subdir_lock);
315 if (!dir_emit(ctx, de->name, de->namelen,
316 de->low_ino, de->mode >> 12)) {
317 pde_put(de);
318 return 0;
319 }
320 ctx->pos++;
321 read_lock(&proc_subdir_lock);
322 next = pde_subdir_next(de);
323 pde_put(de);
324 de = next;
325 } while (de);
326 read_unlock(&proc_subdir_lock);
327 return 1;
328}
329
330int proc_readdir(struct file *file, struct dir_context *ctx)
331{
332 struct inode *inode = file_inode(file);
333 struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
334
335 if (fs_info->pidonly == PROC_PIDONLY_ON)
336 return 1;
337
338 return proc_readdir_de(file, ctx, PDE(inode));
339}
340
341/*
342 * These are the generic /proc directory operations. They
343 * use the in-memory "struct proc_dir_entry" tree to parse
344 * the /proc directory.
345 */
346static const struct file_operations proc_dir_operations = {
347 .llseek = generic_file_llseek,
348 .read = generic_read_dir,
349 .iterate_shared = proc_readdir,
350};
351
352static int proc_net_d_revalidate(struct inode *dir, const struct qstr *name,
353 struct dentry *dentry, unsigned int flags)
354{
355 return 0;
356}
357
358const struct dentry_operations proc_net_dentry_ops = {
359 .d_revalidate = proc_net_d_revalidate,
360 .d_delete = always_delete_dentry,
361};
362
363/*
364 * proc directories can do almost nothing..
365 */
366static const struct inode_operations proc_dir_inode_operations = {
367 .lookup = proc_lookup,
368 .getattr = proc_getattr,
369 .setattr = proc_setattr,
370};
371
372static void pde_set_flags(struct proc_dir_entry *pde)
373{
374 const struct proc_ops *proc_ops = pde->proc_ops;
375
376 if (!proc_ops)
377 return;
378
379 if (proc_ops->proc_flags & PROC_ENTRY_PERMANENT)
380 pde->flags |= PROC_ENTRY_PERMANENT;
381 if (proc_ops->proc_read_iter)
382 pde->flags |= PROC_ENTRY_proc_read_iter;
383#ifdef CONFIG_COMPAT
384 if (proc_ops->proc_compat_ioctl)
385 pde->flags |= PROC_ENTRY_proc_compat_ioctl;
386#endif
387 if (proc_ops->proc_lseek)
388 pde->flags |= PROC_ENTRY_proc_lseek;
389}
390
391/* returns the registered entry, or frees dp and returns NULL on failure */
392struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
393 struct proc_dir_entry *dp)
394{
395 if (proc_alloc_inum(&dp->low_ino))
396 goto out_free_entry;
397
398 if (!S_ISDIR(dp->mode))
399 pde_set_flags(dp);
400
401 write_lock(&proc_subdir_lock);
402 dp->parent = dir;
403 if (pde_subdir_insert(dir, dp) == false) {
404 WARN(1, "proc_dir_entry '%s/%s' already registered\n",
405 dir->name, dp->name);
406 write_unlock(&proc_subdir_lock);
407 goto out_free_inum;
408 }
409 write_unlock(&proc_subdir_lock);
410
411 return dp;
412out_free_inum:
413 proc_free_inum(dp->low_ino);
414out_free_entry:
415 pde_free(dp);
416 return NULL;
417}
418
419static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
420 const char *name,
421 umode_t mode,
422 nlink_t nlink)
423{
424 struct proc_dir_entry *ent = NULL;
425 const char *fn;
426 struct qstr qstr;
427
428 if (xlate_proc_name(name, parent, &fn) != 0)
429 goto out;
430 qstr.name = fn;
431 qstr.len = strnlen(fn, NAME_MAX + 1);
432 if (qstr.len == 0) {
433 WARN(1, "empty name\n");
434 return NULL;
435 }
436 if (qstr.len > NAME_MAX) {
437 WARN(1, "name too long\n");
438 return NULL;
439 }
440 if (qstr.len == 1 && fn[0] == '.') {
441 WARN(1, "name '.'\n");
442 return NULL;
443 }
444 if (qstr.len == 2 && fn[0] == '.' && fn[1] == '.') {
445 WARN(1, "name '..'\n");
446 return NULL;
447 }
448 if (*parent == &proc_root && name_to_int(&qstr) != ~0U) {
449 WARN(1, "create '/proc/%s' by hand\n", qstr.name);
450 return NULL;
451 }
452 if (is_empty_pde(*parent)) {
453 WARN(1, "attempt to add to permanently empty directory");
454 return NULL;
455 }
456
457 ent = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL);
458 if (!ent)
459 goto out;
460
461 if (qstr.len + 1 <= SIZEOF_PDE_INLINE_NAME) {
462 ent->name = ent->inline_name;
463 } else {
464 ent->name = kmalloc(qstr.len + 1, GFP_KERNEL);
465 if (!ent->name) {
466 pde_free(ent);
467 return NULL;
468 }
469 }
470
471 memcpy(ent->name, fn, qstr.len + 1);
472 ent->namelen = qstr.len;
473 ent->mode = mode;
474 ent->nlink = nlink;
475 ent->subdir = RB_ROOT;
476 refcount_set(&ent->refcnt, 1);
477 spin_lock_init(&ent->pde_unload_lock);
478 INIT_LIST_HEAD(&ent->pde_openers);
479 proc_set_user(ent, (*parent)->uid, (*parent)->gid);
480
481 /* Revalidate everything under /proc/${pid}/net */
482 if ((*parent)->flags & PROC_ENTRY_FORCE_LOOKUP)
483 pde_force_lookup(ent);
484
485out:
486 return ent;
487}
488
489struct proc_dir_entry *proc_symlink(const char *name,
490 struct proc_dir_entry *parent, const char *dest)
491{
492 struct proc_dir_entry *ent;
493
494 ent = __proc_create(&parent, name,
495 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
496
497 if (ent) {
498 ent->size = strlen(dest);
499 ent->data = kmemdup(dest, ent->size + 1, GFP_KERNEL);
500 if (ent->data) {
501 ent->proc_iops = &proc_link_inode_operations;
502 ent = proc_register(parent, ent);
503 } else {
504 pde_free(ent);
505 ent = NULL;
506 }
507 }
508 return ent;
509}
510EXPORT_SYMBOL(proc_symlink);
511
512struct proc_dir_entry *_proc_mkdir(const char *name, umode_t mode,
513 struct proc_dir_entry *parent, void *data, bool force_lookup)
514{
515 struct proc_dir_entry *ent;
516
517 if (mode == 0)
518 mode = S_IRUGO | S_IXUGO;
519
520 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
521 if (ent) {
522 ent->data = data;
523 ent->proc_dir_ops = &proc_dir_operations;
524 ent->proc_iops = &proc_dir_inode_operations;
525 if (force_lookup) {
526 pde_force_lookup(ent);
527 }
528 ent = proc_register(parent, ent);
529 }
530 return ent;
531}
532EXPORT_SYMBOL_GPL(_proc_mkdir);
533
534struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
535 struct proc_dir_entry *parent, void *data)
536{
537 return _proc_mkdir(name, mode, parent, data, false);
538}
539EXPORT_SYMBOL_GPL(proc_mkdir_data);
540
541struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
542 struct proc_dir_entry *parent)
543{
544 return proc_mkdir_data(name, mode, parent, NULL);
545}
546EXPORT_SYMBOL(proc_mkdir_mode);
547
548struct proc_dir_entry *proc_mkdir(const char *name,
549 struct proc_dir_entry *parent)
550{
551 return proc_mkdir_data(name, 0, parent, NULL);
552}
553EXPORT_SYMBOL(proc_mkdir);
554
555struct proc_dir_entry *proc_create_mount_point(const char *name)
556{
557 umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO;
558 struct proc_dir_entry *ent, *parent = NULL;
559
560 ent = __proc_create(&parent, name, mode, 2);
561 if (ent) {
562 ent->data = NULL;
563 ent->proc_dir_ops = NULL;
564 ent->proc_iops = NULL;
565 ent = proc_register(parent, ent);
566 }
567 return ent;
568}
569EXPORT_SYMBOL(proc_create_mount_point);
570
571struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
572 struct proc_dir_entry **parent, void *data)
573{
574 struct proc_dir_entry *p;
575
576 if ((mode & S_IFMT) == 0)
577 mode |= S_IFREG;
578 if ((mode & S_IALLUGO) == 0)
579 mode |= S_IRUGO;
580 if (WARN_ON_ONCE(!S_ISREG(mode)))
581 return NULL;
582
583 p = __proc_create(parent, name, mode, 1);
584 if (p) {
585 p->proc_iops = &proc_file_inode_operations;
586 p->data = data;
587 }
588 return p;
589}
590
591struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
592 struct proc_dir_entry *parent,
593 const struct proc_ops *proc_ops, void *data)
594{
595 struct proc_dir_entry *p;
596
597 p = proc_create_reg(name, mode, &parent, data);
598 if (!p)
599 return NULL;
600 p->proc_ops = proc_ops;
601 return proc_register(parent, p);
602}
603EXPORT_SYMBOL(proc_create_data);
604
605struct proc_dir_entry *proc_create(const char *name, umode_t mode,
606 struct proc_dir_entry *parent,
607 const struct proc_ops *proc_ops)
608{
609 return proc_create_data(name, mode, parent, proc_ops, NULL);
610}
611EXPORT_SYMBOL(proc_create);
612
613static int proc_seq_open(struct inode *inode, struct file *file)
614{
615 struct proc_dir_entry *de = PDE(inode);
616
617 if (de->state_size)
618 return seq_open_private(file, de->seq_ops, de->state_size);
619 return seq_open(file, de->seq_ops);
620}
621
622static int proc_seq_release(struct inode *inode, struct file *file)
623{
624 struct proc_dir_entry *de = PDE(inode);
625
626 if (de->state_size)
627 return seq_release_private(inode, file);
628 return seq_release(inode, file);
629}
630
631static const struct proc_ops proc_seq_ops = {
632 /* not permanent -- can call into arbitrary seq_operations */
633 .proc_open = proc_seq_open,
634 .proc_read_iter = seq_read_iter,
635 .proc_lseek = seq_lseek,
636 .proc_release = proc_seq_release,
637};
638
639struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode,
640 struct proc_dir_entry *parent, const struct seq_operations *ops,
641 unsigned int state_size, void *data)
642{
643 struct proc_dir_entry *p;
644
645 p = proc_create_reg(name, mode, &parent, data);
646 if (!p)
647 return NULL;
648 p->proc_ops = &proc_seq_ops;
649 p->seq_ops = ops;
650 p->state_size = state_size;
651 return proc_register(parent, p);
652}
653EXPORT_SYMBOL(proc_create_seq_private);
654
655static int proc_single_open(struct inode *inode, struct file *file)
656{
657 struct proc_dir_entry *de = PDE(inode);
658
659 return single_open(file, de->single_show, de->data);
660}
661
662static const struct proc_ops proc_single_ops = {
663 /* not permanent -- can call into arbitrary ->single_show */
664 .proc_open = proc_single_open,
665 .proc_read_iter = seq_read_iter,
666 .proc_lseek = seq_lseek,
667 .proc_release = single_release,
668};
669
670struct proc_dir_entry *proc_create_single_data(const char *name, umode_t mode,
671 struct proc_dir_entry *parent,
672 int (*show)(struct seq_file *, void *), void *data)
673{
674 struct proc_dir_entry *p;
675
676 p = proc_create_reg(name, mode, &parent, data);
677 if (!p)
678 return NULL;
679 p->proc_ops = &proc_single_ops;
680 p->single_show = show;
681 return proc_register(parent, p);
682}
683EXPORT_SYMBOL(proc_create_single_data);
684
685void proc_set_size(struct proc_dir_entry *de, loff_t size)
686{
687 de->size = size;
688}
689EXPORT_SYMBOL(proc_set_size);
690
691void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
692{
693 de->uid = uid;
694 de->gid = gid;
695}
696EXPORT_SYMBOL(proc_set_user);
697
698void pde_put(struct proc_dir_entry *pde)
699{
700 if (refcount_dec_and_test(&pde->refcnt)) {
701 proc_free_inum(pde->low_ino);
702 pde_free(pde);
703 }
704}
705
706static void pde_erase(struct proc_dir_entry *pde, struct proc_dir_entry *parent)
707{
708 rb_erase(&pde->subdir_node, &parent->subdir);
709 RB_CLEAR_NODE(&pde->subdir_node);
710 if (S_ISDIR(pde->mode))
711 parent->nlink--;
712}
713
714/*
715 * Remove a /proc entry and free it if it's not currently in use.
716 */
717void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
718{
719 struct proc_dir_entry *de = NULL;
720 const char *fn = name;
721 unsigned int len;
722
723 write_lock(&proc_subdir_lock);
724 if (__xlate_proc_name(name, &parent, &fn) != 0) {
725 write_unlock(&proc_subdir_lock);
726 return;
727 }
728 len = strlen(fn);
729
730 de = pde_subdir_find(parent, fn, len);
731 if (de) {
732 if (unlikely(pde_is_permanent(de))) {
733 WARN(1, "removing permanent /proc entry '%s'", de->name);
734 de = NULL;
735 } else {
736 pde_erase(de, parent);
737 }
738 }
739 write_unlock(&proc_subdir_lock);
740 if (!de) {
741 WARN(1, "name '%s'\n", name);
742 return;
743 }
744
745 proc_entry_rundown(de);
746
747 WARN(pde_subdir_first(de),
748 "%s: removing non-empty directory '%s/%s', leaking at least '%s'\n",
749 __func__, de->parent->name, de->name, pde_subdir_first(de)->name);
750 pde_put(de);
751}
752EXPORT_SYMBOL(remove_proc_entry);
753
754int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
755{
756 struct proc_dir_entry *root = NULL, *de, *next;
757 const char *fn = name;
758 unsigned int len;
759
760 write_lock(&proc_subdir_lock);
761 if (__xlate_proc_name(name, &parent, &fn) != 0) {
762 write_unlock(&proc_subdir_lock);
763 return -ENOENT;
764 }
765 len = strlen(fn);
766
767 root = pde_subdir_find(parent, fn, len);
768 if (!root) {
769 write_unlock(&proc_subdir_lock);
770 return -ENOENT;
771 }
772 if (unlikely(pde_is_permanent(root))) {
773 write_unlock(&proc_subdir_lock);
774 WARN(1, "removing permanent /proc entry '%s/%s'",
775 root->parent->name, root->name);
776 return -EINVAL;
777 }
778 pde_erase(root, parent);
779
780 de = root;
781 while (1) {
782 next = pde_subdir_first(de);
783 if (next) {
784 if (unlikely(pde_is_permanent(next))) {
785 write_unlock(&proc_subdir_lock);
786 WARN(1, "removing permanent /proc entry '%s/%s'",
787 next->parent->name, next->name);
788 return -EINVAL;
789 }
790 pde_erase(next, de);
791 de = next;
792 continue;
793 }
794 next = de->parent;
795 write_unlock(&proc_subdir_lock);
796
797 proc_entry_rundown(de);
798 if (de == root)
799 break;
800 pde_put(de);
801
802 write_lock(&proc_subdir_lock);
803 de = next;
804 }
805 pde_put(root);
806 return 0;
807}
808EXPORT_SYMBOL(remove_proc_subtree);
809
810void *proc_get_parent_data(const struct inode *inode)
811{
812 struct proc_dir_entry *de = PDE(inode);
813 return de->parent->data;
814}
815EXPORT_SYMBOL_GPL(proc_get_parent_data);
816
817void proc_remove(struct proc_dir_entry *de)
818{
819 if (de)
820 remove_proc_subtree(de->name, de->parent);
821}
822EXPORT_SYMBOL(proc_remove);
823
824/*
825 * Pull a user buffer into memory and pass it to the file's write handler if
826 * one is supplied. The ->write() method is permitted to modify the
827 * kernel-side buffer.
828 */
829ssize_t proc_simple_write(struct file *f, const char __user *ubuf, size_t size,
830 loff_t *_pos)
831{
832 struct proc_dir_entry *pde = PDE(file_inode(f));
833 char *buf;
834 int ret;
835
836 if (!pde->write)
837 return -EACCES;
838 if (size == 0 || size > PAGE_SIZE - 1)
839 return -EINVAL;
840 buf = memdup_user_nul(ubuf, size);
841 if (IS_ERR(buf))
842 return PTR_ERR(buf);
843 ret = pde->write(f, buf, size);
844 kfree(buf);
845 return ret == 0 ? size : ret;
846}
847
848/*
849 * Not exported to modules:
850 * modules' /proc files aren't permanent because modules aren't permanent.
851 */
852void impl_proc_make_permanent(struct proc_dir_entry *pde)
853{
854 if (pde)
855 pde_make_permanent(pde);
856}