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
33 static DEFINE_RWLOCK(proc_subdir_lock);
34
35 struct kmem_cache *proc_dir_entry_cache __ro_after_init;
36
pde_free(struct proc_dir_entry * pde)37 void 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
proc_match(const char * name,struct proc_dir_entry * de,unsigned int len)46 static 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
pde_subdir_first(struct proc_dir_entry * dir)56 static 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
pde_subdir_next(struct proc_dir_entry * dir)62 static 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
pde_subdir_find(struct proc_dir_entry * dir,const char * name,unsigned int len)68 static 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
pde_subdir_insert(struct proc_dir_entry * dir,struct proc_dir_entry * de)90 static 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
proc_notify_change(struct mnt_idmap * idmap,struct dentry * dentry,struct iattr * iattr)118 static 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
proc_getattr(struct mnt_idmap * idmap,const struct path * path,struct kstat * stat,u32 request_mask,unsigned int query_flags)136 static 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
153 static 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 */
__xlate_proc_name(const char * name,struct proc_dir_entry ** ret,const char ** residual)162 static 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
xlate_proc_name(const char * name,struct proc_dir_entry ** ret,const char ** residual)182 static 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
193 static 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 */
proc_alloc_inum(unsigned int * inum)201 int proc_alloc_inum(unsigned int *inum)
202 {
203 int i;
204
205 i = ida_alloc_max(&proc_inum_ida, UINT_MAX - PROC_DYNAMIC_FIRST,
206 GFP_KERNEL);
207 if (i < 0)
208 return i;
209
210 *inum = PROC_DYNAMIC_FIRST + (unsigned int)i;
211 return 0;
212 }
213
proc_free_inum(unsigned int inum)214 void proc_free_inum(unsigned int inum)
215 {
216 ida_free(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
217 }
218
proc_misc_d_revalidate(struct inode * dir,const struct qstr * name,struct dentry * dentry,unsigned int flags)219 static int proc_misc_d_revalidate(struct inode *dir, const struct qstr *name,
220 struct dentry *dentry, unsigned int flags)
221 {
222 if (flags & LOOKUP_RCU)
223 return -ECHILD;
224
225 if (atomic_read(&PDE(d_inode(dentry))->in_use) < 0)
226 return 0; /* revalidate */
227 return 1;
228 }
229
proc_misc_d_delete(const struct dentry * dentry)230 static int proc_misc_d_delete(const struct dentry *dentry)
231 {
232 return atomic_read(&PDE(d_inode(dentry))->in_use) < 0;
233 }
234
235 static 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 */
proc_lookup_de(struct inode * dir,struct dentry * dentry,struct proc_dir_entry * de)244 struct 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
proc_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)264 struct 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 */
proc_readdir_de(struct file * file,struct dir_context * ctx,struct proc_dir_entry * de)284 int 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
proc_readdir(struct file * file,struct dir_context * ctx)325 int 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 */
341 static const struct file_operations proc_dir_operations = {
342 .llseek = generic_file_llseek,
343 .read = generic_read_dir,
344 .iterate_shared = proc_readdir,
345 };
346
proc_net_d_revalidate(struct inode * dir,const struct qstr * name,struct dentry * dentry,unsigned int flags)347 static int proc_net_d_revalidate(struct inode *dir, const struct qstr *name,
348 struct dentry *dentry, unsigned int flags)
349 {
350 return 0;
351 }
352
353 const struct dentry_operations proc_net_dentry_ops = {
354 .d_revalidate = proc_net_d_revalidate,
355 .d_delete = always_delete_dentry,
356 };
357
358 /*
359 * proc directories can do almost nothing..
360 */
361 static const struct inode_operations proc_dir_inode_operations = {
362 .lookup = proc_lookup,
363 .getattr = proc_getattr,
364 .setattr = proc_notify_change,
365 };
366
367 /* returns the registered entry, or frees dp and returns NULL on failure */
proc_register(struct proc_dir_entry * dir,struct proc_dir_entry * dp)368 struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
369 struct proc_dir_entry *dp)
370 {
371 if (proc_alloc_inum(&dp->low_ino))
372 goto out_free_entry;
373
374 write_lock(&proc_subdir_lock);
375 dp->parent = dir;
376 if (pde_subdir_insert(dir, dp) == false) {
377 WARN(1, "proc_dir_entry '%s/%s' already registered\n",
378 dir->name, dp->name);
379 write_unlock(&proc_subdir_lock);
380 goto out_free_inum;
381 }
382 dir->nlink++;
383 write_unlock(&proc_subdir_lock);
384
385 return dp;
386 out_free_inum:
387 proc_free_inum(dp->low_ino);
388 out_free_entry:
389 pde_free(dp);
390 return NULL;
391 }
392
__proc_create(struct proc_dir_entry ** parent,const char * name,umode_t mode,nlink_t nlink)393 static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
394 const char *name,
395 umode_t mode,
396 nlink_t nlink)
397 {
398 struct proc_dir_entry *ent = NULL;
399 const char *fn;
400 struct qstr qstr;
401
402 if (xlate_proc_name(name, parent, &fn) != 0)
403 goto out;
404 qstr.name = fn;
405 qstr.len = strlen(fn);
406 if (qstr.len == 0 || qstr.len >= 256) {
407 WARN(1, "name len %u\n", qstr.len);
408 return NULL;
409 }
410 if (qstr.len == 1 && fn[0] == '.') {
411 WARN(1, "name '.'\n");
412 return NULL;
413 }
414 if (qstr.len == 2 && fn[0] == '.' && fn[1] == '.') {
415 WARN(1, "name '..'\n");
416 return NULL;
417 }
418 if (*parent == &proc_root && name_to_int(&qstr) != ~0U) {
419 WARN(1, "create '/proc/%s' by hand\n", qstr.name);
420 return NULL;
421 }
422 if (is_empty_pde(*parent)) {
423 WARN(1, "attempt to add to permanently empty directory");
424 return NULL;
425 }
426
427 ent = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL);
428 if (!ent)
429 goto out;
430
431 if (qstr.len + 1 <= SIZEOF_PDE_INLINE_NAME) {
432 ent->name = ent->inline_name;
433 } else {
434 ent->name = kmalloc(qstr.len + 1, GFP_KERNEL);
435 if (!ent->name) {
436 pde_free(ent);
437 return NULL;
438 }
439 }
440
441 memcpy(ent->name, fn, qstr.len + 1);
442 ent->namelen = qstr.len;
443 ent->mode = mode;
444 ent->nlink = nlink;
445 ent->subdir = RB_ROOT;
446 refcount_set(&ent->refcnt, 1);
447 spin_lock_init(&ent->pde_unload_lock);
448 INIT_LIST_HEAD(&ent->pde_openers);
449 proc_set_user(ent, (*parent)->uid, (*parent)->gid);
450
451 ent->proc_dops = &proc_misc_dentry_ops;
452 /* Revalidate everything under /proc/${pid}/net */
453 if ((*parent)->proc_dops == &proc_net_dentry_ops)
454 pde_force_lookup(ent);
455
456 out:
457 return ent;
458 }
459
proc_symlink(const char * name,struct proc_dir_entry * parent,const char * dest)460 struct proc_dir_entry *proc_symlink(const char *name,
461 struct proc_dir_entry *parent, const char *dest)
462 {
463 struct proc_dir_entry *ent;
464
465 ent = __proc_create(&parent, name,
466 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
467
468 if (ent) {
469 ent->size = strlen(dest);
470 ent->data = kmemdup(dest, ent->size + 1, GFP_KERNEL);
471 if (ent->data) {
472 ent->proc_iops = &proc_link_inode_operations;
473 ent = proc_register(parent, ent);
474 } else {
475 pde_free(ent);
476 ent = NULL;
477 }
478 }
479 return ent;
480 }
481 EXPORT_SYMBOL(proc_symlink);
482
_proc_mkdir(const char * name,umode_t mode,struct proc_dir_entry * parent,void * data,bool force_lookup)483 struct proc_dir_entry *_proc_mkdir(const char *name, umode_t mode,
484 struct proc_dir_entry *parent, void *data, bool force_lookup)
485 {
486 struct proc_dir_entry *ent;
487
488 if (mode == 0)
489 mode = S_IRUGO | S_IXUGO;
490
491 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
492 if (ent) {
493 ent->data = data;
494 ent->proc_dir_ops = &proc_dir_operations;
495 ent->proc_iops = &proc_dir_inode_operations;
496 if (force_lookup) {
497 pde_force_lookup(ent);
498 }
499 ent = proc_register(parent, ent);
500 }
501 return ent;
502 }
503 EXPORT_SYMBOL_GPL(_proc_mkdir);
504
proc_mkdir_data(const char * name,umode_t mode,struct proc_dir_entry * parent,void * data)505 struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
506 struct proc_dir_entry *parent, void *data)
507 {
508 return _proc_mkdir(name, mode, parent, data, false);
509 }
510 EXPORT_SYMBOL_GPL(proc_mkdir_data);
511
proc_mkdir_mode(const char * name,umode_t mode,struct proc_dir_entry * parent)512 struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
513 struct proc_dir_entry *parent)
514 {
515 return proc_mkdir_data(name, mode, parent, NULL);
516 }
517 EXPORT_SYMBOL(proc_mkdir_mode);
518
proc_mkdir(const char * name,struct proc_dir_entry * parent)519 struct proc_dir_entry *proc_mkdir(const char *name,
520 struct proc_dir_entry *parent)
521 {
522 return proc_mkdir_data(name, 0, parent, NULL);
523 }
524 EXPORT_SYMBOL(proc_mkdir);
525
proc_create_mount_point(const char * name)526 struct proc_dir_entry *proc_create_mount_point(const char *name)
527 {
528 umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO;
529 struct proc_dir_entry *ent, *parent = NULL;
530
531 ent = __proc_create(&parent, name, mode, 2);
532 if (ent) {
533 ent->data = NULL;
534 ent->proc_dir_ops = NULL;
535 ent->proc_iops = NULL;
536 ent = proc_register(parent, ent);
537 }
538 return ent;
539 }
540 EXPORT_SYMBOL(proc_create_mount_point);
541
proc_create_reg(const char * name,umode_t mode,struct proc_dir_entry ** parent,void * data)542 struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
543 struct proc_dir_entry **parent, void *data)
544 {
545 struct proc_dir_entry *p;
546
547 if ((mode & S_IFMT) == 0)
548 mode |= S_IFREG;
549 if ((mode & S_IALLUGO) == 0)
550 mode |= S_IRUGO;
551 if (WARN_ON_ONCE(!S_ISREG(mode)))
552 return NULL;
553
554 p = __proc_create(parent, name, mode, 1);
555 if (p) {
556 p->proc_iops = &proc_file_inode_operations;
557 p->data = data;
558 }
559 return p;
560 }
561
pde_set_flags(struct proc_dir_entry * pde)562 static void pde_set_flags(struct proc_dir_entry *pde)
563 {
564 if (pde->proc_ops->proc_flags & PROC_ENTRY_PERMANENT)
565 pde->flags |= PROC_ENTRY_PERMANENT;
566 if (pde->proc_ops->proc_read_iter)
567 pde->flags |= PROC_ENTRY_proc_read_iter;
568 #ifdef CONFIG_COMPAT
569 if (pde->proc_ops->proc_compat_ioctl)
570 pde->flags |= PROC_ENTRY_proc_compat_ioctl;
571 #endif
572 }
573
proc_create_data(const char * name,umode_t mode,struct proc_dir_entry * parent,const struct proc_ops * proc_ops,void * data)574 struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
575 struct proc_dir_entry *parent,
576 const struct proc_ops *proc_ops, void *data)
577 {
578 struct proc_dir_entry *p;
579
580 p = proc_create_reg(name, mode, &parent, data);
581 if (!p)
582 return NULL;
583 p->proc_ops = proc_ops;
584 pde_set_flags(p);
585 return proc_register(parent, p);
586 }
587 EXPORT_SYMBOL(proc_create_data);
588
proc_create(const char * name,umode_t mode,struct proc_dir_entry * parent,const struct proc_ops * proc_ops)589 struct proc_dir_entry *proc_create(const char *name, umode_t mode,
590 struct proc_dir_entry *parent,
591 const struct proc_ops *proc_ops)
592 {
593 return proc_create_data(name, mode, parent, proc_ops, NULL);
594 }
595 EXPORT_SYMBOL(proc_create);
596
proc_seq_open(struct inode * inode,struct file * file)597 static int proc_seq_open(struct inode *inode, struct file *file)
598 {
599 struct proc_dir_entry *de = PDE(inode);
600
601 if (de->state_size)
602 return seq_open_private(file, de->seq_ops, de->state_size);
603 return seq_open(file, de->seq_ops);
604 }
605
proc_seq_release(struct inode * inode,struct file * file)606 static int proc_seq_release(struct inode *inode, struct file *file)
607 {
608 struct proc_dir_entry *de = PDE(inode);
609
610 if (de->state_size)
611 return seq_release_private(inode, file);
612 return seq_release(inode, file);
613 }
614
615 static const struct proc_ops proc_seq_ops = {
616 /* not permanent -- can call into arbitrary seq_operations */
617 .proc_open = proc_seq_open,
618 .proc_read_iter = seq_read_iter,
619 .proc_lseek = seq_lseek,
620 .proc_release = proc_seq_release,
621 };
622
proc_create_seq_private(const char * name,umode_t mode,struct proc_dir_entry * parent,const struct seq_operations * ops,unsigned int state_size,void * data)623 struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode,
624 struct proc_dir_entry *parent, const struct seq_operations *ops,
625 unsigned int state_size, void *data)
626 {
627 struct proc_dir_entry *p;
628
629 p = proc_create_reg(name, mode, &parent, data);
630 if (!p)
631 return NULL;
632 p->proc_ops = &proc_seq_ops;
633 p->seq_ops = ops;
634 p->state_size = state_size;
635 pde_set_flags(p);
636 return proc_register(parent, p);
637 }
638 EXPORT_SYMBOL(proc_create_seq_private);
639
proc_single_open(struct inode * inode,struct file * file)640 static int proc_single_open(struct inode *inode, struct file *file)
641 {
642 struct proc_dir_entry *de = PDE(inode);
643
644 return single_open(file, de->single_show, de->data);
645 }
646
647 static const struct proc_ops proc_single_ops = {
648 /* not permanent -- can call into arbitrary ->single_show */
649 .proc_open = proc_single_open,
650 .proc_read_iter = seq_read_iter,
651 .proc_lseek = seq_lseek,
652 .proc_release = single_release,
653 };
654
proc_create_single_data(const char * name,umode_t mode,struct proc_dir_entry * parent,int (* show)(struct seq_file *,void *),void * data)655 struct proc_dir_entry *proc_create_single_data(const char *name, umode_t mode,
656 struct proc_dir_entry *parent,
657 int (*show)(struct seq_file *, void *), void *data)
658 {
659 struct proc_dir_entry *p;
660
661 p = proc_create_reg(name, mode, &parent, data);
662 if (!p)
663 return NULL;
664 p->proc_ops = &proc_single_ops;
665 p->single_show = show;
666 pde_set_flags(p);
667 return proc_register(parent, p);
668 }
669 EXPORT_SYMBOL(proc_create_single_data);
670
proc_set_size(struct proc_dir_entry * de,loff_t size)671 void proc_set_size(struct proc_dir_entry *de, loff_t size)
672 {
673 de->size = size;
674 }
675 EXPORT_SYMBOL(proc_set_size);
676
proc_set_user(struct proc_dir_entry * de,kuid_t uid,kgid_t gid)677 void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
678 {
679 de->uid = uid;
680 de->gid = gid;
681 }
682 EXPORT_SYMBOL(proc_set_user);
683
pde_put(struct proc_dir_entry * pde)684 void pde_put(struct proc_dir_entry *pde)
685 {
686 if (refcount_dec_and_test(&pde->refcnt)) {
687 proc_free_inum(pde->low_ino);
688 pde_free(pde);
689 }
690 }
691
692 /*
693 * Remove a /proc entry and free it if it's not currently in use.
694 */
remove_proc_entry(const char * name,struct proc_dir_entry * parent)695 void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
696 {
697 struct proc_dir_entry *de = NULL;
698 const char *fn = name;
699 unsigned int len;
700
701 write_lock(&proc_subdir_lock);
702 if (__xlate_proc_name(name, &parent, &fn) != 0) {
703 write_unlock(&proc_subdir_lock);
704 return;
705 }
706 len = strlen(fn);
707
708 de = pde_subdir_find(parent, fn, len);
709 if (de) {
710 if (unlikely(pde_is_permanent(de))) {
711 WARN(1, "removing permanent /proc entry '%s'", de->name);
712 de = NULL;
713 } else {
714 rb_erase(&de->subdir_node, &parent->subdir);
715 if (S_ISDIR(de->mode))
716 parent->nlink--;
717 }
718 }
719 write_unlock(&proc_subdir_lock);
720 if (!de) {
721 WARN(1, "name '%s'\n", name);
722 return;
723 }
724
725 proc_entry_rundown(de);
726
727 WARN(pde_subdir_first(de),
728 "%s: removing non-empty directory '%s/%s', leaking at least '%s'\n",
729 __func__, de->parent->name, de->name, pde_subdir_first(de)->name);
730 pde_put(de);
731 }
732 EXPORT_SYMBOL(remove_proc_entry);
733
remove_proc_subtree(const char * name,struct proc_dir_entry * parent)734 int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
735 {
736 struct proc_dir_entry *root = NULL, *de, *next;
737 const char *fn = name;
738 unsigned int len;
739
740 write_lock(&proc_subdir_lock);
741 if (__xlate_proc_name(name, &parent, &fn) != 0) {
742 write_unlock(&proc_subdir_lock);
743 return -ENOENT;
744 }
745 len = strlen(fn);
746
747 root = pde_subdir_find(parent, fn, len);
748 if (!root) {
749 write_unlock(&proc_subdir_lock);
750 return -ENOENT;
751 }
752 if (unlikely(pde_is_permanent(root))) {
753 write_unlock(&proc_subdir_lock);
754 WARN(1, "removing permanent /proc entry '%s/%s'",
755 root->parent->name, root->name);
756 return -EINVAL;
757 }
758 rb_erase(&root->subdir_node, &parent->subdir);
759
760 de = root;
761 while (1) {
762 next = pde_subdir_first(de);
763 if (next) {
764 if (unlikely(pde_is_permanent(next))) {
765 write_unlock(&proc_subdir_lock);
766 WARN(1, "removing permanent /proc entry '%s/%s'",
767 next->parent->name, next->name);
768 return -EINVAL;
769 }
770 rb_erase(&next->subdir_node, &de->subdir);
771 de = next;
772 continue;
773 }
774 next = de->parent;
775 if (S_ISDIR(de->mode))
776 next->nlink--;
777 write_unlock(&proc_subdir_lock);
778
779 proc_entry_rundown(de);
780 if (de == root)
781 break;
782 pde_put(de);
783
784 write_lock(&proc_subdir_lock);
785 de = next;
786 }
787 pde_put(root);
788 return 0;
789 }
790 EXPORT_SYMBOL(remove_proc_subtree);
791
proc_get_parent_data(const struct inode * inode)792 void *proc_get_parent_data(const struct inode *inode)
793 {
794 struct proc_dir_entry *de = PDE(inode);
795 return de->parent->data;
796 }
797 EXPORT_SYMBOL_GPL(proc_get_parent_data);
798
proc_remove(struct proc_dir_entry * de)799 void proc_remove(struct proc_dir_entry *de)
800 {
801 if (de)
802 remove_proc_subtree(de->name, de->parent);
803 }
804 EXPORT_SYMBOL(proc_remove);
805
806 /*
807 * Pull a user buffer into memory and pass it to the file's write handler if
808 * one is supplied. The ->write() method is permitted to modify the
809 * kernel-side buffer.
810 */
proc_simple_write(struct file * f,const char __user * ubuf,size_t size,loff_t * _pos)811 ssize_t proc_simple_write(struct file *f, const char __user *ubuf, size_t size,
812 loff_t *_pos)
813 {
814 struct proc_dir_entry *pde = PDE(file_inode(f));
815 char *buf;
816 int ret;
817
818 if (!pde->write)
819 return -EACCES;
820 if (size == 0 || size > PAGE_SIZE - 1)
821 return -EINVAL;
822 buf = memdup_user_nul(ubuf, size);
823 if (IS_ERR(buf))
824 return PTR_ERR(buf);
825 ret = pde->write(f, buf, size);
826 kfree(buf);
827 return ret == 0 ? size : ret;
828 }
829