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