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 user_namespace * mnt_userns,struct dentry * dentry,struct iattr * iattr)118 static 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
proc_getattr(struct user_namespace * mnt_userns,const struct path * path,struct kstat * stat,u32 request_mask,unsigned int query_flags)137 static 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
154 static 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 */
__xlate_proc_name(const char * name,struct proc_dir_entry ** ret,const char ** residual)163 static 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
xlate_proc_name(const char * name,struct proc_dir_entry ** ret,const char ** residual)183 static 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
194 static 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 */
proc_alloc_inum(unsigned int * inum)202 int 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
proc_free_inum(unsigned int inum)215 void proc_free_inum(unsigned int inum)
216 {
217 ida_simple_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
218 }
219
proc_misc_d_revalidate(struct dentry * dentry,unsigned int flags)220 static 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
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 dentry * dentry,unsigned int flags)347 static int proc_net_d_revalidate(struct dentry *dentry, unsigned int flags)
348 {
349 return 0;
350 }
351
352 const 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 */
360 static 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 */
proc_register(struct proc_dir_entry * dir,struct proc_dir_entry * dp)367 struct 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;
385 out_free_inum:
386 proc_free_inum(dp->low_ino);
387 out_free_entry:
388 pde_free(dp);
389 return NULL;
390 }
391
__proc_create(struct proc_dir_entry ** parent,const char * name,umode_t mode,nlink_t nlink)392 static 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
452 out:
453 return ent;
454 }
455
proc_symlink(const char * name,struct proc_dir_entry * parent,const char * dest)456 struct 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 }
477 EXPORT_SYMBOL(proc_symlink);
478
_proc_mkdir(const char * name,umode_t mode,struct proc_dir_entry * parent,void * data,bool force_lookup)479 struct 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 }
499 EXPORT_SYMBOL_GPL(_proc_mkdir);
500
proc_mkdir_data(const char * name,umode_t mode,struct proc_dir_entry * parent,void * data)501 struct 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 }
506 EXPORT_SYMBOL_GPL(proc_mkdir_data);
507
proc_mkdir_mode(const char * name,umode_t mode,struct proc_dir_entry * parent)508 struct 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 }
513 EXPORT_SYMBOL(proc_mkdir_mode);
514
proc_mkdir(const char * name,struct proc_dir_entry * parent)515 struct 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 }
520 EXPORT_SYMBOL(proc_mkdir);
521
proc_create_mount_point(const char * name)522 struct 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 }
536 EXPORT_SYMBOL(proc_create_mount_point);
537
proc_create_reg(const char * name,umode_t mode,struct proc_dir_entry ** parent,void * data)538 struct 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
pde_set_flags(struct proc_dir_entry * pde)558 static 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
proc_create_data(const char * name,umode_t mode,struct proc_dir_entry * parent,const struct proc_ops * proc_ops,void * data)564 struct 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 }
577 EXPORT_SYMBOL(proc_create_data);
578
proc_create(const char * name,umode_t mode,struct proc_dir_entry * parent,const struct proc_ops * proc_ops)579 struct 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 }
585 EXPORT_SYMBOL(proc_create);
586
proc_seq_open(struct inode * inode,struct file * file)587 static 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
proc_seq_release(struct inode * inode,struct file * file)596 static 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
605 static 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
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)613 struct 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 }
627 EXPORT_SYMBOL(proc_create_seq_private);
628
proc_single_open(struct inode * inode,struct file * file)629 static 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
636 static 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
proc_create_single_data(const char * name,umode_t mode,struct proc_dir_entry * parent,int (* show)(struct seq_file *,void *),void * data)644 struct 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 }
657 EXPORT_SYMBOL(proc_create_single_data);
658
proc_set_size(struct proc_dir_entry * de,loff_t size)659 void proc_set_size(struct proc_dir_entry *de, loff_t size)
660 {
661 de->size = size;
662 }
663 EXPORT_SYMBOL(proc_set_size);
664
proc_set_user(struct proc_dir_entry * de,kuid_t uid,kgid_t gid)665 void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
666 {
667 de->uid = uid;
668 de->gid = gid;
669 }
670 EXPORT_SYMBOL(proc_set_user);
671
pde_put(struct proc_dir_entry * pde)672 void 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 */
remove_proc_entry(const char * name,struct proc_dir_entry * parent)683 void 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 }
720 EXPORT_SYMBOL(remove_proc_entry);
721
remove_proc_subtree(const char * name,struct proc_dir_entry * parent)722 int 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 }
778 EXPORT_SYMBOL(remove_proc_subtree);
779
proc_get_parent_data(const struct inode * inode)780 void *proc_get_parent_data(const struct inode *inode)
781 {
782 struct proc_dir_entry *de = PDE(inode);
783 return de->parent->data;
784 }
785 EXPORT_SYMBOL_GPL(proc_get_parent_data);
786
proc_remove(struct proc_dir_entry * de)787 void proc_remove(struct proc_dir_entry *de)
788 {
789 if (de)
790 remove_proc_subtree(de->name, de->parent);
791 }
792 EXPORT_SYMBOL(proc_remove);
793
PDE_DATA(const struct inode * inode)794 void *PDE_DATA(const struct inode *inode)
795 {
796 return __PDE_DATA(inode);
797 }
798 EXPORT_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 */
proc_simple_write(struct file * f,const char __user * ubuf,size_t size,loff_t * _pos)805 ssize_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 }
823