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1/*
2 * proc/fs/generic.c --- generic routines for the proc-fs
3 *
4 * This file contains generic proc-fs routines for handling
5 * directories and files.
6 *
7 * Copyright (C) 1991, 1992 Linus Torvalds.
8 * Copyright (C) 1997 Theodore Ts'o
9 */
10
11#include <linux/errno.h>
12#include <linux/time.h>
13#include <linux/proc_fs.h>
14#include <linux/stat.h>
15#include <linux/mm.h>
16#include <linux/module.h>
17#include <linux/slab.h>
18#include <linux/mount.h>
19#include <linux/init.h>
20#include <linux/idr.h>
21#include <linux/namei.h>
22#include <linux/bitops.h>
23#include <linux/spinlock.h>
24#include <linux/completion.h>
25#include <asm/uaccess.h>
26
27#include "internal.h"
28
29DEFINE_SPINLOCK(proc_subdir_lock);
30
31static int proc_match(unsigned int len, const char *name, struct proc_dir_entry *de)
32{
33 if (de->namelen != len)
34 return 0;
35 return !memcmp(name, de->name, len);
36}
37
38/* buffer size is one page but our output routines use some slack for overruns */
39#define PROC_BLOCK_SIZE (PAGE_SIZE - 1024)
40
41static ssize_t
42__proc_file_read(struct file *file, char __user *buf, size_t nbytes,
43 loff_t *ppos)
44{
45 struct inode * inode = file->f_path.dentry->d_inode;
46 char *page;
47 ssize_t retval=0;
48 int eof=0;
49 ssize_t n, count;
50 char *start;
51 struct proc_dir_entry * dp;
52 unsigned long long pos;
53
54 /*
55 * Gaah, please just use "seq_file" instead. The legacy /proc
56 * interfaces cut loff_t down to off_t for reads, and ignore
57 * the offset entirely for writes..
58 */
59 pos = *ppos;
60 if (pos > MAX_NON_LFS)
61 return 0;
62 if (nbytes > MAX_NON_LFS - pos)
63 nbytes = MAX_NON_LFS - pos;
64
65 dp = PDE(inode);
66 if (!(page = (char*) __get_free_page(GFP_TEMPORARY)))
67 return -ENOMEM;
68
69 while ((nbytes > 0) && !eof) {
70 count = min_t(size_t, PROC_BLOCK_SIZE, nbytes);
71
72 start = NULL;
73 if (dp->read_proc) {
74 /*
75 * How to be a proc read function
76 * ------------------------------
77 * Prototype:
78 * int f(char *buffer, char **start, off_t offset,
79 * int count, int *peof, void *dat)
80 *
81 * Assume that the buffer is "count" bytes in size.
82 *
83 * If you know you have supplied all the data you
84 * have, set *peof.
85 *
86 * You have three ways to return data:
87 * 0) Leave *start = NULL. (This is the default.)
88 * Put the data of the requested offset at that
89 * offset within the buffer. Return the number (n)
90 * of bytes there are from the beginning of the
91 * buffer up to the last byte of data. If the
92 * number of supplied bytes (= n - offset) is
93 * greater than zero and you didn't signal eof
94 * and the reader is prepared to take more data
95 * you will be called again with the requested
96 * offset advanced by the number of bytes
97 * absorbed. This interface is useful for files
98 * no larger than the buffer.
99 * 1) Set *start = an unsigned long value less than
100 * the buffer address but greater than zero.
101 * Put the data of the requested offset at the
102 * beginning of the buffer. Return the number of
103 * bytes of data placed there. If this number is
104 * greater than zero and you didn't signal eof
105 * and the reader is prepared to take more data
106 * you will be called again with the requested
107 * offset advanced by *start. This interface is
108 * useful when you have a large file consisting
109 * of a series of blocks which you want to count
110 * and return as wholes.
111 * (Hack by Paul.Russell@rustcorp.com.au)
112 * 2) Set *start = an address within the buffer.
113 * Put the data of the requested offset at *start.
114 * Return the number of bytes of data placed there.
115 * If this number is greater than zero and you
116 * didn't signal eof and the reader is prepared to
117 * take more data you will be called again with the
118 * requested offset advanced by the number of bytes
119 * absorbed.
120 */
121 n = dp->read_proc(page, &start, *ppos,
122 count, &eof, dp->data);
123 } else
124 break;
125
126 if (n == 0) /* end of file */
127 break;
128 if (n < 0) { /* error */
129 if (retval == 0)
130 retval = n;
131 break;
132 }
133
134 if (start == NULL) {
135 if (n > PAGE_SIZE) {
136 printk(KERN_ERR
137 "proc_file_read: Apparent buffer overflow!\n");
138 n = PAGE_SIZE;
139 }
140 n -= *ppos;
141 if (n <= 0)
142 break;
143 if (n > count)
144 n = count;
145 start = page + *ppos;
146 } else if (start < page) {
147 if (n > PAGE_SIZE) {
148 printk(KERN_ERR
149 "proc_file_read: Apparent buffer overflow!\n");
150 n = PAGE_SIZE;
151 }
152 if (n > count) {
153 /*
154 * Don't reduce n because doing so might
155 * cut off part of a data block.
156 */
157 printk(KERN_WARNING
158 "proc_file_read: Read count exceeded\n");
159 }
160 } else /* start >= page */ {
161 unsigned long startoff = (unsigned long)(start - page);
162 if (n > (PAGE_SIZE - startoff)) {
163 printk(KERN_ERR
164 "proc_file_read: Apparent buffer overflow!\n");
165 n = PAGE_SIZE - startoff;
166 }
167 if (n > count)
168 n = count;
169 }
170
171 n -= copy_to_user(buf, start < page ? page : start, n);
172 if (n == 0) {
173 if (retval == 0)
174 retval = -EFAULT;
175 break;
176 }
177
178 *ppos += start < page ? (unsigned long)start : n;
179 nbytes -= n;
180 buf += n;
181 retval += n;
182 }
183 free_page((unsigned long) page);
184 return retval;
185}
186
187static ssize_t
188proc_file_read(struct file *file, char __user *buf, size_t nbytes,
189 loff_t *ppos)
190{
191 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
192 ssize_t rv = -EIO;
193
194 spin_lock(&pde->pde_unload_lock);
195 if (!pde->proc_fops) {
196 spin_unlock(&pde->pde_unload_lock);
197 return rv;
198 }
199 pde->pde_users++;
200 spin_unlock(&pde->pde_unload_lock);
201
202 rv = __proc_file_read(file, buf, nbytes, ppos);
203
204 pde_users_dec(pde);
205 return rv;
206}
207
208static ssize_t
209proc_file_write(struct file *file, const char __user *buffer,
210 size_t count, loff_t *ppos)
211{
212 struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
213 ssize_t rv = -EIO;
214
215 if (pde->write_proc) {
216 spin_lock(&pde->pde_unload_lock);
217 if (!pde->proc_fops) {
218 spin_unlock(&pde->pde_unload_lock);
219 return rv;
220 }
221 pde->pde_users++;
222 spin_unlock(&pde->pde_unload_lock);
223
224 /* FIXME: does this routine need ppos? probably... */
225 rv = pde->write_proc(file, buffer, count, pde->data);
226 pde_users_dec(pde);
227 }
228 return rv;
229}
230
231
232static loff_t
233proc_file_lseek(struct file *file, loff_t offset, int orig)
234{
235 loff_t retval = -EINVAL;
236 switch (orig) {
237 case 1:
238 offset += file->f_pos;
239 /* fallthrough */
240 case 0:
241 if (offset < 0 || offset > MAX_NON_LFS)
242 break;
243 file->f_pos = retval = offset;
244 }
245 return retval;
246}
247
248static const struct file_operations proc_file_operations = {
249 .llseek = proc_file_lseek,
250 .read = proc_file_read,
251 .write = proc_file_write,
252};
253
254static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
255{
256 struct inode *inode = dentry->d_inode;
257 struct proc_dir_entry *de = PDE(inode);
258 int error;
259
260 error = inode_change_ok(inode, iattr);
261 if (error)
262 return error;
263
264 if ((iattr->ia_valid & ATTR_SIZE) &&
265 iattr->ia_size != i_size_read(inode)) {
266 error = vmtruncate(inode, iattr->ia_size);
267 if (error)
268 return error;
269 }
270
271 setattr_copy(inode, iattr);
272 mark_inode_dirty(inode);
273
274 de->uid = inode->i_uid;
275 de->gid = inode->i_gid;
276 de->mode = inode->i_mode;
277 return 0;
278}
279
280static int proc_getattr(struct vfsmount *mnt, struct dentry *dentry,
281 struct kstat *stat)
282{
283 struct inode *inode = dentry->d_inode;
284 struct proc_dir_entry *de = PROC_I(inode)->pde;
285 if (de && de->nlink)
286 inode->i_nlink = de->nlink;
287
288 generic_fillattr(inode, stat);
289 return 0;
290}
291
292static const struct inode_operations proc_file_inode_operations = {
293 .setattr = proc_notify_change,
294};
295
296/*
297 * This function parses a name such as "tty/driver/serial", and
298 * returns the struct proc_dir_entry for "/proc/tty/driver", and
299 * returns "serial" in residual.
300 */
301static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
302 const char **residual)
303{
304 const char *cp = name, *next;
305 struct proc_dir_entry *de;
306 unsigned int len;
307
308 de = *ret;
309 if (!de)
310 de = &proc_root;
311
312 while (1) {
313 next = strchr(cp, '/');
314 if (!next)
315 break;
316
317 len = next - cp;
318 for (de = de->subdir; de ; de = de->next) {
319 if (proc_match(len, cp, de))
320 break;
321 }
322 if (!de) {
323 WARN(1, "name '%s'\n", name);
324 return -ENOENT;
325 }
326 cp += len + 1;
327 }
328 *residual = cp;
329 *ret = de;
330 return 0;
331}
332
333static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
334 const char **residual)
335{
336 int rv;
337
338 spin_lock(&proc_subdir_lock);
339 rv = __xlate_proc_name(name, ret, residual);
340 spin_unlock(&proc_subdir_lock);
341 return rv;
342}
343
344static DEFINE_IDA(proc_inum_ida);
345static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */
346
347#define PROC_DYNAMIC_FIRST 0xF0000000U
348
349/*
350 * Return an inode number between PROC_DYNAMIC_FIRST and
351 * 0xffffffff, or zero on failure.
352 */
353static unsigned int get_inode_number(void)
354{
355 unsigned int i;
356 int error;
357
358retry:
359 if (ida_pre_get(&proc_inum_ida, GFP_KERNEL) == 0)
360 return 0;
361
362 spin_lock(&proc_inum_lock);
363 error = ida_get_new(&proc_inum_ida, &i);
364 spin_unlock(&proc_inum_lock);
365 if (error == -EAGAIN)
366 goto retry;
367 else if (error)
368 return 0;
369
370 if (i > UINT_MAX - PROC_DYNAMIC_FIRST) {
371 spin_lock(&proc_inum_lock);
372 ida_remove(&proc_inum_ida, i);
373 spin_unlock(&proc_inum_lock);
374 return 0;
375 }
376 return PROC_DYNAMIC_FIRST + i;
377}
378
379static void release_inode_number(unsigned int inum)
380{
381 spin_lock(&proc_inum_lock);
382 ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
383 spin_unlock(&proc_inum_lock);
384}
385
386static void *proc_follow_link(struct dentry *dentry, struct nameidata *nd)
387{
388 nd_set_link(nd, PDE(dentry->d_inode)->data);
389 return NULL;
390}
391
392static const struct inode_operations proc_link_inode_operations = {
393 .readlink = generic_readlink,
394 .follow_link = proc_follow_link,
395};
396
397/*
398 * As some entries in /proc are volatile, we want to
399 * get rid of unused dentries. This could be made
400 * smarter: we could keep a "volatile" flag in the
401 * inode to indicate which ones to keep.
402 */
403static int proc_delete_dentry(const struct dentry * dentry)
404{
405 return 1;
406}
407
408static const struct dentry_operations proc_dentry_operations =
409{
410 .d_delete = proc_delete_dentry,
411};
412
413/*
414 * Don't create negative dentries here, return -ENOENT by hand
415 * instead.
416 */
417struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
418 struct dentry *dentry)
419{
420 struct inode *inode = NULL;
421 int error = -ENOENT;
422
423 spin_lock(&proc_subdir_lock);
424 for (de = de->subdir; de ; de = de->next) {
425 if (de->namelen != dentry->d_name.len)
426 continue;
427 if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
428 pde_get(de);
429 spin_unlock(&proc_subdir_lock);
430 error = -EINVAL;
431 inode = proc_get_inode(dir->i_sb, de);
432 goto out_unlock;
433 }
434 }
435 spin_unlock(&proc_subdir_lock);
436out_unlock:
437
438 if (inode) {
439 d_set_d_op(dentry, &proc_dentry_operations);
440 d_add(dentry, inode);
441 return NULL;
442 }
443 if (de)
444 pde_put(de);
445 return ERR_PTR(error);
446}
447
448struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
449 struct nameidata *nd)
450{
451 return proc_lookup_de(PDE(dir), dir, dentry);
452}
453
454/*
455 * This returns non-zero if at EOF, so that the /proc
456 * root directory can use this and check if it should
457 * continue with the <pid> entries..
458 *
459 * Note that the VFS-layer doesn't care about the return
460 * value of the readdir() call, as long as it's non-negative
461 * for success..
462 */
463int proc_readdir_de(struct proc_dir_entry *de, struct file *filp, void *dirent,
464 filldir_t filldir)
465{
466 unsigned int ino;
467 int i;
468 struct inode *inode = filp->f_path.dentry->d_inode;
469 int ret = 0;
470
471 ino = inode->i_ino;
472 i = filp->f_pos;
473 switch (i) {
474 case 0:
475 if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
476 goto out;
477 i++;
478 filp->f_pos++;
479 /* fall through */
480 case 1:
481 if (filldir(dirent, "..", 2, i,
482 parent_ino(filp->f_path.dentry),
483 DT_DIR) < 0)
484 goto out;
485 i++;
486 filp->f_pos++;
487 /* fall through */
488 default:
489 spin_lock(&proc_subdir_lock);
490 de = de->subdir;
491 i -= 2;
492 for (;;) {
493 if (!de) {
494 ret = 1;
495 spin_unlock(&proc_subdir_lock);
496 goto out;
497 }
498 if (!i)
499 break;
500 de = de->next;
501 i--;
502 }
503
504 do {
505 struct proc_dir_entry *next;
506
507 /* filldir passes info to user space */
508 pde_get(de);
509 spin_unlock(&proc_subdir_lock);
510 if (filldir(dirent, de->name, de->namelen, filp->f_pos,
511 de->low_ino, de->mode >> 12) < 0) {
512 pde_put(de);
513 goto out;
514 }
515 spin_lock(&proc_subdir_lock);
516 filp->f_pos++;
517 next = de->next;
518 pde_put(de);
519 de = next;
520 } while (de);
521 spin_unlock(&proc_subdir_lock);
522 }
523 ret = 1;
524out:
525 return ret;
526}
527
528int proc_readdir(struct file *filp, void *dirent, filldir_t filldir)
529{
530 struct inode *inode = filp->f_path.dentry->d_inode;
531
532 return proc_readdir_de(PDE(inode), filp, dirent, filldir);
533}
534
535/*
536 * These are the generic /proc directory operations. They
537 * use the in-memory "struct proc_dir_entry" tree to parse
538 * the /proc directory.
539 */
540static const struct file_operations proc_dir_operations = {
541 .llseek = generic_file_llseek,
542 .read = generic_read_dir,
543 .readdir = proc_readdir,
544};
545
546/*
547 * proc directories can do almost nothing..
548 */
549static const struct inode_operations proc_dir_inode_operations = {
550 .lookup = proc_lookup,
551 .getattr = proc_getattr,
552 .setattr = proc_notify_change,
553};
554
555static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
556{
557 unsigned int i;
558 struct proc_dir_entry *tmp;
559
560 i = get_inode_number();
561 if (i == 0)
562 return -EAGAIN;
563 dp->low_ino = i;
564
565 if (S_ISDIR(dp->mode)) {
566 if (dp->proc_iops == NULL) {
567 dp->proc_fops = &proc_dir_operations;
568 dp->proc_iops = &proc_dir_inode_operations;
569 }
570 dir->nlink++;
571 } else if (S_ISLNK(dp->mode)) {
572 if (dp->proc_iops == NULL)
573 dp->proc_iops = &proc_link_inode_operations;
574 } else if (S_ISREG(dp->mode)) {
575 if (dp->proc_fops == NULL)
576 dp->proc_fops = &proc_file_operations;
577 if (dp->proc_iops == NULL)
578 dp->proc_iops = &proc_file_inode_operations;
579 }
580
581 spin_lock(&proc_subdir_lock);
582
583 for (tmp = dir->subdir; tmp; tmp = tmp->next)
584 if (strcmp(tmp->name, dp->name) == 0) {
585 WARN(1, KERN_WARNING "proc_dir_entry '%s/%s' already registered\n",
586 dir->name, dp->name);
587 break;
588 }
589
590 dp->next = dir->subdir;
591 dp->parent = dir;
592 dir->subdir = dp;
593 spin_unlock(&proc_subdir_lock);
594
595 return 0;
596}
597
598static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
599 const char *name,
600 mode_t mode,
601 nlink_t nlink)
602{
603 struct proc_dir_entry *ent = NULL;
604 const char *fn = name;
605 unsigned int len;
606
607 /* make sure name is valid */
608 if (!name || !strlen(name)) goto out;
609
610 if (xlate_proc_name(name, parent, &fn) != 0)
611 goto out;
612
613 /* At this point there must not be any '/' characters beyond *fn */
614 if (strchr(fn, '/'))
615 goto out;
616
617 len = strlen(fn);
618
619 ent = kmalloc(sizeof(struct proc_dir_entry) + len + 1, GFP_KERNEL);
620 if (!ent) goto out;
621
622 memset(ent, 0, sizeof(struct proc_dir_entry));
623 memcpy(ent->name, fn, len + 1);
624 ent->namelen = len;
625 ent->mode = mode;
626 ent->nlink = nlink;
627 atomic_set(&ent->count, 1);
628 ent->pde_users = 0;
629 spin_lock_init(&ent->pde_unload_lock);
630 ent->pde_unload_completion = NULL;
631 INIT_LIST_HEAD(&ent->pde_openers);
632 out:
633 return ent;
634}
635
636struct proc_dir_entry *proc_symlink(const char *name,
637 struct proc_dir_entry *parent, const char *dest)
638{
639 struct proc_dir_entry *ent;
640
641 ent = __proc_create(&parent, name,
642 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
643
644 if (ent) {
645 ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
646 if (ent->data) {
647 strcpy((char*)ent->data,dest);
648 if (proc_register(parent, ent) < 0) {
649 kfree(ent->data);
650 kfree(ent);
651 ent = NULL;
652 }
653 } else {
654 kfree(ent);
655 ent = NULL;
656 }
657 }
658 return ent;
659}
660EXPORT_SYMBOL(proc_symlink);
661
662struct proc_dir_entry *proc_mkdir_mode(const char *name, mode_t mode,
663 struct proc_dir_entry *parent)
664{
665 struct proc_dir_entry *ent;
666
667 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
668 if (ent) {
669 if (proc_register(parent, ent) < 0) {
670 kfree(ent);
671 ent = NULL;
672 }
673 }
674 return ent;
675}
676EXPORT_SYMBOL(proc_mkdir_mode);
677
678struct proc_dir_entry *proc_net_mkdir(struct net *net, const char *name,
679 struct proc_dir_entry *parent)
680{
681 struct proc_dir_entry *ent;
682
683 ent = __proc_create(&parent, name, S_IFDIR | S_IRUGO | S_IXUGO, 2);
684 if (ent) {
685 ent->data = net;
686 if (proc_register(parent, ent) < 0) {
687 kfree(ent);
688 ent = NULL;
689 }
690 }
691 return ent;
692}
693EXPORT_SYMBOL_GPL(proc_net_mkdir);
694
695struct proc_dir_entry *proc_mkdir(const char *name,
696 struct proc_dir_entry *parent)
697{
698 return proc_mkdir_mode(name, S_IRUGO | S_IXUGO, parent);
699}
700EXPORT_SYMBOL(proc_mkdir);
701
702struct proc_dir_entry *create_proc_entry(const char *name, mode_t mode,
703 struct proc_dir_entry *parent)
704{
705 struct proc_dir_entry *ent;
706 nlink_t nlink;
707
708 if (S_ISDIR(mode)) {
709 if ((mode & S_IALLUGO) == 0)
710 mode |= S_IRUGO | S_IXUGO;
711 nlink = 2;
712 } else {
713 if ((mode & S_IFMT) == 0)
714 mode |= S_IFREG;
715 if ((mode & S_IALLUGO) == 0)
716 mode |= S_IRUGO;
717 nlink = 1;
718 }
719
720 ent = __proc_create(&parent, name, mode, nlink);
721 if (ent) {
722 if (proc_register(parent, ent) < 0) {
723 kfree(ent);
724 ent = NULL;
725 }
726 }
727 return ent;
728}
729EXPORT_SYMBOL(create_proc_entry);
730
731struct proc_dir_entry *proc_create_data(const char *name, mode_t mode,
732 struct proc_dir_entry *parent,
733 const struct file_operations *proc_fops,
734 void *data)
735{
736 struct proc_dir_entry *pde;
737 nlink_t nlink;
738
739 if (S_ISDIR(mode)) {
740 if ((mode & S_IALLUGO) == 0)
741 mode |= S_IRUGO | S_IXUGO;
742 nlink = 2;
743 } else {
744 if ((mode & S_IFMT) == 0)
745 mode |= S_IFREG;
746 if ((mode & S_IALLUGO) == 0)
747 mode |= S_IRUGO;
748 nlink = 1;
749 }
750
751 pde = __proc_create(&parent, name, mode, nlink);
752 if (!pde)
753 goto out;
754 pde->proc_fops = proc_fops;
755 pde->data = data;
756 if (proc_register(parent, pde) < 0)
757 goto out_free;
758 return pde;
759out_free:
760 kfree(pde);
761out:
762 return NULL;
763}
764EXPORT_SYMBOL(proc_create_data);
765
766static void free_proc_entry(struct proc_dir_entry *de)
767{
768 release_inode_number(de->low_ino);
769
770 if (S_ISLNK(de->mode))
771 kfree(de->data);
772 kfree(de);
773}
774
775void pde_put(struct proc_dir_entry *pde)
776{
777 if (atomic_dec_and_test(&pde->count))
778 free_proc_entry(pde);
779}
780
781/*
782 * Remove a /proc entry and free it if it's not currently in use.
783 */
784void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
785{
786 struct proc_dir_entry **p;
787 struct proc_dir_entry *de = NULL;
788 const char *fn = name;
789 unsigned int len;
790
791 spin_lock(&proc_subdir_lock);
792 if (__xlate_proc_name(name, &parent, &fn) != 0) {
793 spin_unlock(&proc_subdir_lock);
794 return;
795 }
796 len = strlen(fn);
797
798 for (p = &parent->subdir; *p; p=&(*p)->next ) {
799 if (proc_match(len, fn, *p)) {
800 de = *p;
801 *p = de->next;
802 de->next = NULL;
803 break;
804 }
805 }
806 spin_unlock(&proc_subdir_lock);
807 if (!de) {
808 WARN(1, "name '%s'\n", name);
809 return;
810 }
811
812 spin_lock(&de->pde_unload_lock);
813 /*
814 * Stop accepting new callers into module. If you're
815 * dynamically allocating ->proc_fops, save a pointer somewhere.
816 */
817 de->proc_fops = NULL;
818 /* Wait until all existing callers into module are done. */
819 if (de->pde_users > 0) {
820 DECLARE_COMPLETION_ONSTACK(c);
821
822 if (!de->pde_unload_completion)
823 de->pde_unload_completion = &c;
824
825 spin_unlock(&de->pde_unload_lock);
826
827 wait_for_completion(de->pde_unload_completion);
828
829 spin_lock(&de->pde_unload_lock);
830 }
831
832 while (!list_empty(&de->pde_openers)) {
833 struct pde_opener *pdeo;
834
835 pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
836 list_del(&pdeo->lh);
837 spin_unlock(&de->pde_unload_lock);
838 pdeo->release(pdeo->inode, pdeo->file);
839 kfree(pdeo);
840 spin_lock(&de->pde_unload_lock);
841 }
842 spin_unlock(&de->pde_unload_lock);
843
844 if (S_ISDIR(de->mode))
845 parent->nlink--;
846 de->nlink = 0;
847 WARN(de->subdir, KERN_WARNING "%s: removing non-empty directory "
848 "'%s/%s', leaking at least '%s'\n", __func__,
849 de->parent->name, de->name, de->subdir->name);
850 pde_put(de);
851}
852EXPORT_SYMBOL(remove_proc_entry);
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}