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