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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/printk.h>
19#include <linux/mount.h>
20#include <linux/init.h>
21#include <linux/idr.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
29static DEFINE_RWLOCK(proc_subdir_lock);
30
31static int proc_match(unsigned int len, const char *name, struct proc_dir_entry *de)
32{
33 if (len < de->namelen)
34 return -1;
35 if (len > de->namelen)
36 return 1;
37
38 return memcmp(name, de->name, len);
39}
40
41static struct proc_dir_entry *pde_subdir_first(struct proc_dir_entry *dir)
42{
43 return rb_entry_safe(rb_first(&dir->subdir), struct proc_dir_entry,
44 subdir_node);
45}
46
47static struct proc_dir_entry *pde_subdir_next(struct proc_dir_entry *dir)
48{
49 return rb_entry_safe(rb_next(&dir->subdir_node), struct proc_dir_entry,
50 subdir_node);
51}
52
53static struct proc_dir_entry *pde_subdir_find(struct proc_dir_entry *dir,
54 const char *name,
55 unsigned int len)
56{
57 struct rb_node *node = dir->subdir.rb_node;
58
59 while (node) {
60 struct proc_dir_entry *de = container_of(node,
61 struct proc_dir_entry,
62 subdir_node);
63 int result = proc_match(len, name, de);
64
65 if (result < 0)
66 node = node->rb_left;
67 else if (result > 0)
68 node = node->rb_right;
69 else
70 return de;
71 }
72 return NULL;
73}
74
75static bool pde_subdir_insert(struct proc_dir_entry *dir,
76 struct proc_dir_entry *de)
77{
78 struct rb_root *root = &dir->subdir;
79 struct rb_node **new = &root->rb_node, *parent = NULL;
80
81 /* Figure out where to put new node */
82 while (*new) {
83 struct proc_dir_entry *this =
84 container_of(*new, struct proc_dir_entry, subdir_node);
85 int result = proc_match(de->namelen, de->name, this);
86
87 parent = *new;
88 if (result < 0)
89 new = &(*new)->rb_left;
90 else if (result > 0)
91 new = &(*new)->rb_right;
92 else
93 return false;
94 }
95
96 /* Add new node and rebalance tree. */
97 rb_link_node(&de->subdir_node, parent, new);
98 rb_insert_color(&de->subdir_node, root);
99 return true;
100}
101
102static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
103{
104 struct inode *inode = d_inode(dentry);
105 struct proc_dir_entry *de = PDE(inode);
106 int error;
107
108 error = inode_change_ok(inode, iattr);
109 if (error)
110 return error;
111
112 setattr_copy(inode, iattr);
113 mark_inode_dirty(inode);
114
115 proc_set_user(de, inode->i_uid, inode->i_gid);
116 de->mode = inode->i_mode;
117 return 0;
118}
119
120static int proc_getattr(struct vfsmount *mnt, struct dentry *dentry,
121 struct kstat *stat)
122{
123 struct inode *inode = d_inode(dentry);
124 struct proc_dir_entry *de = PDE(inode);
125 if (de && de->nlink)
126 set_nlink(inode, de->nlink);
127
128 generic_fillattr(inode, stat);
129 return 0;
130}
131
132static const struct inode_operations proc_file_inode_operations = {
133 .setattr = proc_notify_change,
134};
135
136/*
137 * This function parses a name such as "tty/driver/serial", and
138 * returns the struct proc_dir_entry for "/proc/tty/driver", and
139 * returns "serial" in residual.
140 */
141static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
142 const char **residual)
143{
144 const char *cp = name, *next;
145 struct proc_dir_entry *de;
146 unsigned int len;
147
148 de = *ret;
149 if (!de)
150 de = &proc_root;
151
152 while (1) {
153 next = strchr(cp, '/');
154 if (!next)
155 break;
156
157 len = next - cp;
158 de = pde_subdir_find(de, cp, len);
159 if (!de) {
160 WARN(1, "name '%s'\n", name);
161 return -ENOENT;
162 }
163 cp += len + 1;
164 }
165 *residual = cp;
166 *ret = de;
167 return 0;
168}
169
170static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
171 const char **residual)
172{
173 int rv;
174
175 read_lock(&proc_subdir_lock);
176 rv = __xlate_proc_name(name, ret, residual);
177 read_unlock(&proc_subdir_lock);
178 return rv;
179}
180
181static DEFINE_IDA(proc_inum_ida);
182static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */
183
184#define PROC_DYNAMIC_FIRST 0xF0000000U
185
186/*
187 * Return an inode number between PROC_DYNAMIC_FIRST and
188 * 0xffffffff, or zero on failure.
189 */
190int proc_alloc_inum(unsigned int *inum)
191{
192 unsigned int i;
193 int error;
194
195retry:
196 if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL))
197 return -ENOMEM;
198
199 spin_lock_irq(&proc_inum_lock);
200 error = ida_get_new(&proc_inum_ida, &i);
201 spin_unlock_irq(&proc_inum_lock);
202 if (error == -EAGAIN)
203 goto retry;
204 else if (error)
205 return error;
206
207 if (i > UINT_MAX - PROC_DYNAMIC_FIRST) {
208 spin_lock_irq(&proc_inum_lock);
209 ida_remove(&proc_inum_ida, i);
210 spin_unlock_irq(&proc_inum_lock);
211 return -ENOSPC;
212 }
213 *inum = PROC_DYNAMIC_FIRST + i;
214 return 0;
215}
216
217void proc_free_inum(unsigned int inum)
218{
219 unsigned long flags;
220 spin_lock_irqsave(&proc_inum_lock, flags);
221 ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
222 spin_unlock_irqrestore(&proc_inum_lock, flags);
223}
224
225/*
226 * Don't create negative dentries here, return -ENOENT by hand
227 * instead.
228 */
229struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
230 struct dentry *dentry)
231{
232 struct inode *inode;
233
234 read_lock(&proc_subdir_lock);
235 de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len);
236 if (de) {
237 pde_get(de);
238 read_unlock(&proc_subdir_lock);
239 inode = proc_get_inode(dir->i_sb, de);
240 if (!inode)
241 return ERR_PTR(-ENOMEM);
242 d_set_d_op(dentry, &simple_dentry_operations);
243 d_add(dentry, inode);
244 return NULL;
245 }
246 read_unlock(&proc_subdir_lock);
247 return ERR_PTR(-ENOENT);
248}
249
250struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
251 unsigned int flags)
252{
253 return proc_lookup_de(PDE(dir), dir, dentry);
254}
255
256/*
257 * This returns non-zero if at EOF, so that the /proc
258 * root directory can use this and check if it should
259 * continue with the <pid> entries..
260 *
261 * Note that the VFS-layer doesn't care about the return
262 * value of the readdir() call, as long as it's non-negative
263 * for success..
264 */
265int proc_readdir_de(struct proc_dir_entry *de, struct file *file,
266 struct dir_context *ctx)
267{
268 int i;
269
270 if (!dir_emit_dots(file, ctx))
271 return 0;
272
273 read_lock(&proc_subdir_lock);
274 de = pde_subdir_first(de);
275 i = ctx->pos - 2;
276 for (;;) {
277 if (!de) {
278 read_unlock(&proc_subdir_lock);
279 return 0;
280 }
281 if (!i)
282 break;
283 de = pde_subdir_next(de);
284 i--;
285 }
286
287 do {
288 struct proc_dir_entry *next;
289 pde_get(de);
290 read_unlock(&proc_subdir_lock);
291 if (!dir_emit(ctx, de->name, de->namelen,
292 de->low_ino, de->mode >> 12)) {
293 pde_put(de);
294 return 0;
295 }
296 read_lock(&proc_subdir_lock);
297 ctx->pos++;
298 next = pde_subdir_next(de);
299 pde_put(de);
300 de = next;
301 } while (de);
302 read_unlock(&proc_subdir_lock);
303 return 1;
304}
305
306int proc_readdir(struct file *file, struct dir_context *ctx)
307{
308 struct inode *inode = file_inode(file);
309
310 return proc_readdir_de(PDE(inode), file, ctx);
311}
312
313/*
314 * These are the generic /proc directory operations. They
315 * use the in-memory "struct proc_dir_entry" tree to parse
316 * the /proc directory.
317 */
318static const struct file_operations proc_dir_operations = {
319 .llseek = generic_file_llseek,
320 .read = generic_read_dir,
321 .iterate = proc_readdir,
322};
323
324/*
325 * proc directories can do almost nothing..
326 */
327static const struct inode_operations proc_dir_inode_operations = {
328 .lookup = proc_lookup,
329 .getattr = proc_getattr,
330 .setattr = proc_notify_change,
331};
332
333static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
334{
335 int ret;
336
337 ret = proc_alloc_inum(&dp->low_ino);
338 if (ret)
339 return ret;
340
341 write_lock(&proc_subdir_lock);
342 dp->parent = dir;
343 if (pde_subdir_insert(dir, dp) == false) {
344 WARN(1, "proc_dir_entry '%s/%s' already registered\n",
345 dir->name, dp->name);
346 write_unlock(&proc_subdir_lock);
347 proc_free_inum(dp->low_ino);
348 return -EEXIST;
349 }
350 write_unlock(&proc_subdir_lock);
351
352 return 0;
353}
354
355static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
356 const char *name,
357 umode_t mode,
358 nlink_t nlink)
359{
360 struct proc_dir_entry *ent = NULL;
361 const char *fn;
362 struct qstr qstr;
363
364 if (xlate_proc_name(name, parent, &fn) != 0)
365 goto out;
366 qstr.name = fn;
367 qstr.len = strlen(fn);
368 if (qstr.len == 0 || qstr.len >= 256) {
369 WARN(1, "name len %u\n", qstr.len);
370 return NULL;
371 }
372 if (*parent == &proc_root && name_to_int(&qstr) != ~0U) {
373 WARN(1, "create '/proc/%s' by hand\n", qstr.name);
374 return NULL;
375 }
376 if (is_empty_pde(*parent)) {
377 WARN(1, "attempt to add to permanently empty directory");
378 return NULL;
379 }
380
381 ent = kzalloc(sizeof(struct proc_dir_entry) + qstr.len + 1, GFP_KERNEL);
382 if (!ent)
383 goto out;
384
385 memcpy(ent->name, fn, qstr.len + 1);
386 ent->namelen = qstr.len;
387 ent->mode = mode;
388 ent->nlink = nlink;
389 ent->subdir = RB_ROOT;
390 atomic_set(&ent->count, 1);
391 spin_lock_init(&ent->pde_unload_lock);
392 INIT_LIST_HEAD(&ent->pde_openers);
393out:
394 return ent;
395}
396
397struct proc_dir_entry *proc_symlink(const char *name,
398 struct proc_dir_entry *parent, const char *dest)
399{
400 struct proc_dir_entry *ent;
401
402 ent = __proc_create(&parent, name,
403 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
404
405 if (ent) {
406 ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
407 if (ent->data) {
408 strcpy((char*)ent->data,dest);
409 ent->proc_iops = &proc_link_inode_operations;
410 if (proc_register(parent, ent) < 0) {
411 kfree(ent->data);
412 kfree(ent);
413 ent = NULL;
414 }
415 } else {
416 kfree(ent);
417 ent = NULL;
418 }
419 }
420 return ent;
421}
422EXPORT_SYMBOL(proc_symlink);
423
424struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
425 struct proc_dir_entry *parent, void *data)
426{
427 struct proc_dir_entry *ent;
428
429 if (mode == 0)
430 mode = S_IRUGO | S_IXUGO;
431
432 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
433 if (ent) {
434 ent->data = data;
435 ent->proc_fops = &proc_dir_operations;
436 ent->proc_iops = &proc_dir_inode_operations;
437 parent->nlink++;
438 if (proc_register(parent, ent) < 0) {
439 kfree(ent);
440 parent->nlink--;
441 ent = NULL;
442 }
443 }
444 return ent;
445}
446EXPORT_SYMBOL_GPL(proc_mkdir_data);
447
448struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
449 struct proc_dir_entry *parent)
450{
451 return proc_mkdir_data(name, mode, parent, NULL);
452}
453EXPORT_SYMBOL(proc_mkdir_mode);
454
455struct proc_dir_entry *proc_mkdir(const char *name,
456 struct proc_dir_entry *parent)
457{
458 return proc_mkdir_data(name, 0, parent, NULL);
459}
460EXPORT_SYMBOL(proc_mkdir);
461
462struct proc_dir_entry *proc_create_mount_point(const char *name)
463{
464 umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO;
465 struct proc_dir_entry *ent, *parent = NULL;
466
467 ent = __proc_create(&parent, name, mode, 2);
468 if (ent) {
469 ent->data = NULL;
470 ent->proc_fops = NULL;
471 ent->proc_iops = NULL;
472 if (proc_register(parent, ent) < 0) {
473 kfree(ent);
474 parent->nlink--;
475 ent = NULL;
476 }
477 }
478 return ent;
479}
480
481struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
482 struct proc_dir_entry *parent,
483 const struct file_operations *proc_fops,
484 void *data)
485{
486 struct proc_dir_entry *pde;
487 if ((mode & S_IFMT) == 0)
488 mode |= S_IFREG;
489
490 if (!S_ISREG(mode)) {
491 WARN_ON(1); /* use proc_mkdir() */
492 return NULL;
493 }
494
495 BUG_ON(proc_fops == NULL);
496
497 if ((mode & S_IALLUGO) == 0)
498 mode |= S_IRUGO;
499 pde = __proc_create(&parent, name, mode, 1);
500 if (!pde)
501 goto out;
502 pde->proc_fops = proc_fops;
503 pde->data = data;
504 pde->proc_iops = &proc_file_inode_operations;
505 if (proc_register(parent, pde) < 0)
506 goto out_free;
507 return pde;
508out_free:
509 kfree(pde);
510out:
511 return NULL;
512}
513EXPORT_SYMBOL(proc_create_data);
514
515void proc_set_size(struct proc_dir_entry *de, loff_t size)
516{
517 de->size = size;
518}
519EXPORT_SYMBOL(proc_set_size);
520
521void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
522{
523 de->uid = uid;
524 de->gid = gid;
525}
526EXPORT_SYMBOL(proc_set_user);
527
528static void free_proc_entry(struct proc_dir_entry *de)
529{
530 proc_free_inum(de->low_ino);
531
532 if (S_ISLNK(de->mode))
533 kfree(de->data);
534 kfree(de);
535}
536
537void pde_put(struct proc_dir_entry *pde)
538{
539 if (atomic_dec_and_test(&pde->count))
540 free_proc_entry(pde);
541}
542
543/*
544 * Remove a /proc entry and free it if it's not currently in use.
545 */
546void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
547{
548 struct proc_dir_entry *de = NULL;
549 const char *fn = name;
550 unsigned int len;
551
552 write_lock(&proc_subdir_lock);
553 if (__xlate_proc_name(name, &parent, &fn) != 0) {
554 write_unlock(&proc_subdir_lock);
555 return;
556 }
557 len = strlen(fn);
558
559 de = pde_subdir_find(parent, fn, len);
560 if (de)
561 rb_erase(&de->subdir_node, &parent->subdir);
562 write_unlock(&proc_subdir_lock);
563 if (!de) {
564 WARN(1, "name '%s'\n", name);
565 return;
566 }
567
568 proc_entry_rundown(de);
569
570 if (S_ISDIR(de->mode))
571 parent->nlink--;
572 de->nlink = 0;
573 WARN(pde_subdir_first(de),
574 "%s: removing non-empty directory '%s/%s', leaking at least '%s'\n",
575 __func__, de->parent->name, de->name, pde_subdir_first(de)->name);
576 pde_put(de);
577}
578EXPORT_SYMBOL(remove_proc_entry);
579
580int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
581{
582 struct proc_dir_entry *root = NULL, *de, *next;
583 const char *fn = name;
584 unsigned int len;
585
586 write_lock(&proc_subdir_lock);
587 if (__xlate_proc_name(name, &parent, &fn) != 0) {
588 write_unlock(&proc_subdir_lock);
589 return -ENOENT;
590 }
591 len = strlen(fn);
592
593 root = pde_subdir_find(parent, fn, len);
594 if (!root) {
595 write_unlock(&proc_subdir_lock);
596 return -ENOENT;
597 }
598 rb_erase(&root->subdir_node, &parent->subdir);
599
600 de = root;
601 while (1) {
602 next = pde_subdir_first(de);
603 if (next) {
604 rb_erase(&next->subdir_node, &de->subdir);
605 de = next;
606 continue;
607 }
608 write_unlock(&proc_subdir_lock);
609
610 proc_entry_rundown(de);
611 next = de->parent;
612 if (S_ISDIR(de->mode))
613 next->nlink--;
614 de->nlink = 0;
615 if (de == root)
616 break;
617 pde_put(de);
618
619 write_lock(&proc_subdir_lock);
620 de = next;
621 }
622 pde_put(root);
623 return 0;
624}
625EXPORT_SYMBOL(remove_proc_subtree);
626
627void *proc_get_parent_data(const struct inode *inode)
628{
629 struct proc_dir_entry *de = PDE(inode);
630 return de->parent->data;
631}
632EXPORT_SYMBOL_GPL(proc_get_parent_data);
633
634void proc_remove(struct proc_dir_entry *de)
635{
636 if (de)
637 remove_proc_subtree(de->name, de->parent);
638}
639EXPORT_SYMBOL(proc_remove);
640
641void *PDE_DATA(const struct inode *inode)
642{
643 return __PDE_DATA(inode);
644}
645EXPORT_SYMBOL(PDE_DATA);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * proc/fs/generic.c --- generic routines for the proc-fs
4 *
5 * This file contains generic proc-fs routines for handling
6 * directories and files.
7 *
8 * Copyright (C) 1991, 1992 Linus Torvalds.
9 * Copyright (C) 1997 Theodore Ts'o
10 */
11
12#include <linux/cache.h>
13#include <linux/errno.h>
14#include <linux/time.h>
15#include <linux/proc_fs.h>
16#include <linux/stat.h>
17#include <linux/mm.h>
18#include <linux/module.h>
19#include <linux/namei.h>
20#include <linux/slab.h>
21#include <linux/printk.h>
22#include <linux/mount.h>
23#include <linux/init.h>
24#include <linux/idr.h>
25#include <linux/bitops.h>
26#include <linux/spinlock.h>
27#include <linux/completion.h>
28#include <linux/uaccess.h>
29#include <linux/seq_file.h>
30
31#include "internal.h"
32
33static DEFINE_RWLOCK(proc_subdir_lock);
34
35struct kmem_cache *proc_dir_entry_cache __ro_after_init;
36
37void pde_free(struct proc_dir_entry *pde)
38{
39 if (S_ISLNK(pde->mode))
40 kfree(pde->data);
41 if (pde->name != pde->inline_name)
42 kfree(pde->name);
43 kmem_cache_free(proc_dir_entry_cache, pde);
44}
45
46static int proc_match(const char *name, struct proc_dir_entry *de, unsigned int len)
47{
48 if (len < de->namelen)
49 return -1;
50 if (len > de->namelen)
51 return 1;
52
53 return memcmp(name, de->name, len);
54}
55
56static struct proc_dir_entry *pde_subdir_first(struct proc_dir_entry *dir)
57{
58 return rb_entry_safe(rb_first(&dir->subdir), struct proc_dir_entry,
59 subdir_node);
60}
61
62static struct proc_dir_entry *pde_subdir_next(struct proc_dir_entry *dir)
63{
64 return rb_entry_safe(rb_next(&dir->subdir_node), struct proc_dir_entry,
65 subdir_node);
66}
67
68static struct proc_dir_entry *pde_subdir_find(struct proc_dir_entry *dir,
69 const char *name,
70 unsigned int len)
71{
72 struct rb_node *node = dir->subdir.rb_node;
73
74 while (node) {
75 struct proc_dir_entry *de = rb_entry(node,
76 struct proc_dir_entry,
77 subdir_node);
78 int result = proc_match(name, de, len);
79
80 if (result < 0)
81 node = node->rb_left;
82 else if (result > 0)
83 node = node->rb_right;
84 else
85 return de;
86 }
87 return NULL;
88}
89
90static bool pde_subdir_insert(struct proc_dir_entry *dir,
91 struct proc_dir_entry *de)
92{
93 struct rb_root *root = &dir->subdir;
94 struct rb_node **new = &root->rb_node, *parent = NULL;
95
96 /* Figure out where to put new node */
97 while (*new) {
98 struct proc_dir_entry *this = rb_entry(*new,
99 struct proc_dir_entry,
100 subdir_node);
101 int result = proc_match(de->name, this, de->namelen);
102
103 parent = *new;
104 if (result < 0)
105 new = &(*new)->rb_left;
106 else if (result > 0)
107 new = &(*new)->rb_right;
108 else
109 return false;
110 }
111
112 /* Add new node and rebalance tree. */
113 rb_link_node(&de->subdir_node, parent, new);
114 rb_insert_color(&de->subdir_node, root);
115 return true;
116}
117
118static int proc_notify_change(struct user_namespace *mnt_userns,
119 struct dentry *dentry, struct iattr *iattr)
120{
121 struct inode *inode = d_inode(dentry);
122 struct proc_dir_entry *de = PDE(inode);
123 int error;
124
125 error = setattr_prepare(&init_user_ns, dentry, iattr);
126 if (error)
127 return error;
128
129 setattr_copy(&init_user_ns, inode, iattr);
130 mark_inode_dirty(inode);
131
132 proc_set_user(de, inode->i_uid, inode->i_gid);
133 de->mode = inode->i_mode;
134 return 0;
135}
136
137static int proc_getattr(struct user_namespace *mnt_userns,
138 const struct path *path, struct kstat *stat,
139 u32 request_mask, unsigned int query_flags)
140{
141 struct inode *inode = d_inode(path->dentry);
142 struct proc_dir_entry *de = PDE(inode);
143 if (de) {
144 nlink_t nlink = READ_ONCE(de->nlink);
145 if (nlink > 0) {
146 set_nlink(inode, nlink);
147 }
148 }
149
150 generic_fillattr(&init_user_ns, inode, stat);
151 return 0;
152}
153
154static const struct inode_operations proc_file_inode_operations = {
155 .setattr = proc_notify_change,
156};
157
158/*
159 * This function parses a name such as "tty/driver/serial", and
160 * returns the struct proc_dir_entry for "/proc/tty/driver", and
161 * returns "serial" in residual.
162 */
163static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
164 const char **residual)
165{
166 const char *cp = name, *next;
167 struct proc_dir_entry *de;
168
169 de = *ret ?: &proc_root;
170 while ((next = strchr(cp, '/')) != NULL) {
171 de = pde_subdir_find(de, cp, next - cp);
172 if (!de) {
173 WARN(1, "name '%s'\n", name);
174 return -ENOENT;
175 }
176 cp = next + 1;
177 }
178 *residual = cp;
179 *ret = de;
180 return 0;
181}
182
183static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
184 const char **residual)
185{
186 int rv;
187
188 read_lock(&proc_subdir_lock);
189 rv = __xlate_proc_name(name, ret, residual);
190 read_unlock(&proc_subdir_lock);
191 return rv;
192}
193
194static DEFINE_IDA(proc_inum_ida);
195
196#define PROC_DYNAMIC_FIRST 0xF0000000U
197
198/*
199 * Return an inode number between PROC_DYNAMIC_FIRST and
200 * 0xffffffff, or zero on failure.
201 */
202int proc_alloc_inum(unsigned int *inum)
203{
204 int i;
205
206 i = ida_simple_get(&proc_inum_ida, 0, UINT_MAX - PROC_DYNAMIC_FIRST + 1,
207 GFP_KERNEL);
208 if (i < 0)
209 return i;
210
211 *inum = PROC_DYNAMIC_FIRST + (unsigned int)i;
212 return 0;
213}
214
215void proc_free_inum(unsigned int inum)
216{
217 ida_simple_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
218}
219
220static int proc_misc_d_revalidate(struct dentry *dentry, unsigned int flags)
221{
222 if (flags & LOOKUP_RCU)
223 return -ECHILD;
224
225 if (atomic_read(&PDE(d_inode(dentry))->in_use) < 0)
226 return 0; /* revalidate */
227 return 1;
228}
229
230static int proc_misc_d_delete(const struct dentry *dentry)
231{
232 return atomic_read(&PDE(d_inode(dentry))->in_use) < 0;
233}
234
235static const struct dentry_operations proc_misc_dentry_ops = {
236 .d_revalidate = proc_misc_d_revalidate,
237 .d_delete = proc_misc_d_delete,
238};
239
240/*
241 * Don't create negative dentries here, return -ENOENT by hand
242 * instead.
243 */
244struct dentry *proc_lookup_de(struct inode *dir, struct dentry *dentry,
245 struct proc_dir_entry *de)
246{
247 struct inode *inode;
248
249 read_lock(&proc_subdir_lock);
250 de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len);
251 if (de) {
252 pde_get(de);
253 read_unlock(&proc_subdir_lock);
254 inode = proc_get_inode(dir->i_sb, de);
255 if (!inode)
256 return ERR_PTR(-ENOMEM);
257 d_set_d_op(dentry, de->proc_dops);
258 return d_splice_alias(inode, dentry);
259 }
260 read_unlock(&proc_subdir_lock);
261 return ERR_PTR(-ENOENT);
262}
263
264struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
265 unsigned int flags)
266{
267 struct proc_fs_info *fs_info = proc_sb_info(dir->i_sb);
268
269 if (fs_info->pidonly == PROC_PIDONLY_ON)
270 return ERR_PTR(-ENOENT);
271
272 return proc_lookup_de(dir, dentry, PDE(dir));
273}
274
275/*
276 * This returns non-zero if at EOF, so that the /proc
277 * root directory can use this and check if it should
278 * continue with the <pid> entries..
279 *
280 * Note that the VFS-layer doesn't care about the return
281 * value of the readdir() call, as long as it's non-negative
282 * for success..
283 */
284int proc_readdir_de(struct file *file, struct dir_context *ctx,
285 struct proc_dir_entry *de)
286{
287 int i;
288
289 if (!dir_emit_dots(file, ctx))
290 return 0;
291
292 i = ctx->pos - 2;
293 read_lock(&proc_subdir_lock);
294 de = pde_subdir_first(de);
295 for (;;) {
296 if (!de) {
297 read_unlock(&proc_subdir_lock);
298 return 0;
299 }
300 if (!i)
301 break;
302 de = pde_subdir_next(de);
303 i--;
304 }
305
306 do {
307 struct proc_dir_entry *next;
308 pde_get(de);
309 read_unlock(&proc_subdir_lock);
310 if (!dir_emit(ctx, de->name, de->namelen,
311 de->low_ino, de->mode >> 12)) {
312 pde_put(de);
313 return 0;
314 }
315 ctx->pos++;
316 read_lock(&proc_subdir_lock);
317 next = pde_subdir_next(de);
318 pde_put(de);
319 de = next;
320 } while (de);
321 read_unlock(&proc_subdir_lock);
322 return 1;
323}
324
325int proc_readdir(struct file *file, struct dir_context *ctx)
326{
327 struct inode *inode = file_inode(file);
328 struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
329
330 if (fs_info->pidonly == PROC_PIDONLY_ON)
331 return 1;
332
333 return proc_readdir_de(file, ctx, PDE(inode));
334}
335
336/*
337 * These are the generic /proc directory operations. They
338 * use the in-memory "struct proc_dir_entry" tree to parse
339 * the /proc directory.
340 */
341static const struct file_operations proc_dir_operations = {
342 .llseek = generic_file_llseek,
343 .read = generic_read_dir,
344 .iterate_shared = proc_readdir,
345};
346
347static int proc_net_d_revalidate(struct dentry *dentry, unsigned int flags)
348{
349 return 0;
350}
351
352const struct dentry_operations proc_net_dentry_ops = {
353 .d_revalidate = proc_net_d_revalidate,
354 .d_delete = always_delete_dentry,
355};
356
357/*
358 * proc directories can do almost nothing..
359 */
360static const struct inode_operations proc_dir_inode_operations = {
361 .lookup = proc_lookup,
362 .getattr = proc_getattr,
363 .setattr = proc_notify_change,
364};
365
366/* returns the registered entry, or frees dp and returns NULL on failure */
367struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
368 struct proc_dir_entry *dp)
369{
370 if (proc_alloc_inum(&dp->low_ino))
371 goto out_free_entry;
372
373 write_lock(&proc_subdir_lock);
374 dp->parent = dir;
375 if (pde_subdir_insert(dir, dp) == false) {
376 WARN(1, "proc_dir_entry '%s/%s' already registered\n",
377 dir->name, dp->name);
378 write_unlock(&proc_subdir_lock);
379 goto out_free_inum;
380 }
381 dir->nlink++;
382 write_unlock(&proc_subdir_lock);
383
384 return dp;
385out_free_inum:
386 proc_free_inum(dp->low_ino);
387out_free_entry:
388 pde_free(dp);
389 return NULL;
390}
391
392static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
393 const char *name,
394 umode_t mode,
395 nlink_t nlink)
396{
397 struct proc_dir_entry *ent = NULL;
398 const char *fn;
399 struct qstr qstr;
400
401 if (xlate_proc_name(name, parent, &fn) != 0)
402 goto out;
403 qstr.name = fn;
404 qstr.len = strlen(fn);
405 if (qstr.len == 0 || qstr.len >= 256) {
406 WARN(1, "name len %u\n", qstr.len);
407 return NULL;
408 }
409 if (qstr.len == 1 && fn[0] == '.') {
410 WARN(1, "name '.'\n");
411 return NULL;
412 }
413 if (qstr.len == 2 && fn[0] == '.' && fn[1] == '.') {
414 WARN(1, "name '..'\n");
415 return NULL;
416 }
417 if (*parent == &proc_root && name_to_int(&qstr) != ~0U) {
418 WARN(1, "create '/proc/%s' by hand\n", qstr.name);
419 return NULL;
420 }
421 if (is_empty_pde(*parent)) {
422 WARN(1, "attempt to add to permanently empty directory");
423 return NULL;
424 }
425
426 ent = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL);
427 if (!ent)
428 goto out;
429
430 if (qstr.len + 1 <= SIZEOF_PDE_INLINE_NAME) {
431 ent->name = ent->inline_name;
432 } else {
433 ent->name = kmalloc(qstr.len + 1, GFP_KERNEL);
434 if (!ent->name) {
435 pde_free(ent);
436 return NULL;
437 }
438 }
439
440 memcpy(ent->name, fn, qstr.len + 1);
441 ent->namelen = qstr.len;
442 ent->mode = mode;
443 ent->nlink = nlink;
444 ent->subdir = RB_ROOT;
445 refcount_set(&ent->refcnt, 1);
446 spin_lock_init(&ent->pde_unload_lock);
447 INIT_LIST_HEAD(&ent->pde_openers);
448 proc_set_user(ent, (*parent)->uid, (*parent)->gid);
449
450 ent->proc_dops = &proc_misc_dentry_ops;
451
452out:
453 return ent;
454}
455
456struct proc_dir_entry *proc_symlink(const char *name,
457 struct proc_dir_entry *parent, const char *dest)
458{
459 struct proc_dir_entry *ent;
460
461 ent = __proc_create(&parent, name,
462 (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
463
464 if (ent) {
465 ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
466 if (ent->data) {
467 strcpy((char*)ent->data,dest);
468 ent->proc_iops = &proc_link_inode_operations;
469 ent = proc_register(parent, ent);
470 } else {
471 pde_free(ent);
472 ent = NULL;
473 }
474 }
475 return ent;
476}
477EXPORT_SYMBOL(proc_symlink);
478
479struct proc_dir_entry *_proc_mkdir(const char *name, umode_t mode,
480 struct proc_dir_entry *parent, void *data, bool force_lookup)
481{
482 struct proc_dir_entry *ent;
483
484 if (mode == 0)
485 mode = S_IRUGO | S_IXUGO;
486
487 ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
488 if (ent) {
489 ent->data = data;
490 ent->proc_dir_ops = &proc_dir_operations;
491 ent->proc_iops = &proc_dir_inode_operations;
492 if (force_lookup) {
493 pde_force_lookup(ent);
494 }
495 ent = proc_register(parent, ent);
496 }
497 return ent;
498}
499EXPORT_SYMBOL_GPL(_proc_mkdir);
500
501struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
502 struct proc_dir_entry *parent, void *data)
503{
504 return _proc_mkdir(name, mode, parent, data, false);
505}
506EXPORT_SYMBOL_GPL(proc_mkdir_data);
507
508struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
509 struct proc_dir_entry *parent)
510{
511 return proc_mkdir_data(name, mode, parent, NULL);
512}
513EXPORT_SYMBOL(proc_mkdir_mode);
514
515struct proc_dir_entry *proc_mkdir(const char *name,
516 struct proc_dir_entry *parent)
517{
518 return proc_mkdir_data(name, 0, parent, NULL);
519}
520EXPORT_SYMBOL(proc_mkdir);
521
522struct proc_dir_entry *proc_create_mount_point(const char *name)
523{
524 umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO;
525 struct proc_dir_entry *ent, *parent = NULL;
526
527 ent = __proc_create(&parent, name, mode, 2);
528 if (ent) {
529 ent->data = NULL;
530 ent->proc_dir_ops = NULL;
531 ent->proc_iops = NULL;
532 ent = proc_register(parent, ent);
533 }
534 return ent;
535}
536EXPORT_SYMBOL(proc_create_mount_point);
537
538struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
539 struct proc_dir_entry **parent, void *data)
540{
541 struct proc_dir_entry *p;
542
543 if ((mode & S_IFMT) == 0)
544 mode |= S_IFREG;
545 if ((mode & S_IALLUGO) == 0)
546 mode |= S_IRUGO;
547 if (WARN_ON_ONCE(!S_ISREG(mode)))
548 return NULL;
549
550 p = __proc_create(parent, name, mode, 1);
551 if (p) {
552 p->proc_iops = &proc_file_inode_operations;
553 p->data = data;
554 }
555 return p;
556}
557
558static inline void pde_set_flags(struct proc_dir_entry *pde)
559{
560 if (pde->proc_ops->proc_flags & PROC_ENTRY_PERMANENT)
561 pde->flags |= PROC_ENTRY_PERMANENT;
562}
563
564struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
565 struct proc_dir_entry *parent,
566 const struct proc_ops *proc_ops, void *data)
567{
568 struct proc_dir_entry *p;
569
570 p = proc_create_reg(name, mode, &parent, data);
571 if (!p)
572 return NULL;
573 p->proc_ops = proc_ops;
574 pde_set_flags(p);
575 return proc_register(parent, p);
576}
577EXPORT_SYMBOL(proc_create_data);
578
579struct proc_dir_entry *proc_create(const char *name, umode_t mode,
580 struct proc_dir_entry *parent,
581 const struct proc_ops *proc_ops)
582{
583 return proc_create_data(name, mode, parent, proc_ops, NULL);
584}
585EXPORT_SYMBOL(proc_create);
586
587static int proc_seq_open(struct inode *inode, struct file *file)
588{
589 struct proc_dir_entry *de = PDE(inode);
590
591 if (de->state_size)
592 return seq_open_private(file, de->seq_ops, de->state_size);
593 return seq_open(file, de->seq_ops);
594}
595
596static int proc_seq_release(struct inode *inode, struct file *file)
597{
598 struct proc_dir_entry *de = PDE(inode);
599
600 if (de->state_size)
601 return seq_release_private(inode, file);
602 return seq_release(inode, file);
603}
604
605static const struct proc_ops proc_seq_ops = {
606 /* not permanent -- can call into arbitrary seq_operations */
607 .proc_open = proc_seq_open,
608 .proc_read_iter = seq_read_iter,
609 .proc_lseek = seq_lseek,
610 .proc_release = proc_seq_release,
611};
612
613struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode,
614 struct proc_dir_entry *parent, const struct seq_operations *ops,
615 unsigned int state_size, void *data)
616{
617 struct proc_dir_entry *p;
618
619 p = proc_create_reg(name, mode, &parent, data);
620 if (!p)
621 return NULL;
622 p->proc_ops = &proc_seq_ops;
623 p->seq_ops = ops;
624 p->state_size = state_size;
625 return proc_register(parent, p);
626}
627EXPORT_SYMBOL(proc_create_seq_private);
628
629static int proc_single_open(struct inode *inode, struct file *file)
630{
631 struct proc_dir_entry *de = PDE(inode);
632
633 return single_open(file, de->single_show, de->data);
634}
635
636static const struct proc_ops proc_single_ops = {
637 /* not permanent -- can call into arbitrary ->single_show */
638 .proc_open = proc_single_open,
639 .proc_read_iter = seq_read_iter,
640 .proc_lseek = seq_lseek,
641 .proc_release = single_release,
642};
643
644struct proc_dir_entry *proc_create_single_data(const char *name, umode_t mode,
645 struct proc_dir_entry *parent,
646 int (*show)(struct seq_file *, void *), void *data)
647{
648 struct proc_dir_entry *p;
649
650 p = proc_create_reg(name, mode, &parent, data);
651 if (!p)
652 return NULL;
653 p->proc_ops = &proc_single_ops;
654 p->single_show = show;
655 return proc_register(parent, p);
656}
657EXPORT_SYMBOL(proc_create_single_data);
658
659void proc_set_size(struct proc_dir_entry *de, loff_t size)
660{
661 de->size = size;
662}
663EXPORT_SYMBOL(proc_set_size);
664
665void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
666{
667 de->uid = uid;
668 de->gid = gid;
669}
670EXPORT_SYMBOL(proc_set_user);
671
672void pde_put(struct proc_dir_entry *pde)
673{
674 if (refcount_dec_and_test(&pde->refcnt)) {
675 proc_free_inum(pde->low_ino);
676 pde_free(pde);
677 }
678}
679
680/*
681 * Remove a /proc entry and free it if it's not currently in use.
682 */
683void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
684{
685 struct proc_dir_entry *de = NULL;
686 const char *fn = name;
687 unsigned int len;
688
689 write_lock(&proc_subdir_lock);
690 if (__xlate_proc_name(name, &parent, &fn) != 0) {
691 write_unlock(&proc_subdir_lock);
692 return;
693 }
694 len = strlen(fn);
695
696 de = pde_subdir_find(parent, fn, len);
697 if (de) {
698 if (unlikely(pde_is_permanent(de))) {
699 WARN(1, "removing permanent /proc entry '%s'", de->name);
700 de = NULL;
701 } else {
702 rb_erase(&de->subdir_node, &parent->subdir);
703 if (S_ISDIR(de->mode))
704 parent->nlink--;
705 }
706 }
707 write_unlock(&proc_subdir_lock);
708 if (!de) {
709 WARN(1, "name '%s'\n", name);
710 return;
711 }
712
713 proc_entry_rundown(de);
714
715 WARN(pde_subdir_first(de),
716 "%s: removing non-empty directory '%s/%s', leaking at least '%s'\n",
717 __func__, de->parent->name, de->name, pde_subdir_first(de)->name);
718 pde_put(de);
719}
720EXPORT_SYMBOL(remove_proc_entry);
721
722int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
723{
724 struct proc_dir_entry *root = NULL, *de, *next;
725 const char *fn = name;
726 unsigned int len;
727
728 write_lock(&proc_subdir_lock);
729 if (__xlate_proc_name(name, &parent, &fn) != 0) {
730 write_unlock(&proc_subdir_lock);
731 return -ENOENT;
732 }
733 len = strlen(fn);
734
735 root = pde_subdir_find(parent, fn, len);
736 if (!root) {
737 write_unlock(&proc_subdir_lock);
738 return -ENOENT;
739 }
740 if (unlikely(pde_is_permanent(root))) {
741 write_unlock(&proc_subdir_lock);
742 WARN(1, "removing permanent /proc entry '%s/%s'",
743 root->parent->name, root->name);
744 return -EINVAL;
745 }
746 rb_erase(&root->subdir_node, &parent->subdir);
747
748 de = root;
749 while (1) {
750 next = pde_subdir_first(de);
751 if (next) {
752 if (unlikely(pde_is_permanent(next))) {
753 write_unlock(&proc_subdir_lock);
754 WARN(1, "removing permanent /proc entry '%s/%s'",
755 next->parent->name, next->name);
756 return -EINVAL;
757 }
758 rb_erase(&next->subdir_node, &de->subdir);
759 de = next;
760 continue;
761 }
762 next = de->parent;
763 if (S_ISDIR(de->mode))
764 next->nlink--;
765 write_unlock(&proc_subdir_lock);
766
767 proc_entry_rundown(de);
768 if (de == root)
769 break;
770 pde_put(de);
771
772 write_lock(&proc_subdir_lock);
773 de = next;
774 }
775 pde_put(root);
776 return 0;
777}
778EXPORT_SYMBOL(remove_proc_subtree);
779
780void *proc_get_parent_data(const struct inode *inode)
781{
782 struct proc_dir_entry *de = PDE(inode);
783 return de->parent->data;
784}
785EXPORT_SYMBOL_GPL(proc_get_parent_data);
786
787void proc_remove(struct proc_dir_entry *de)
788{
789 if (de)
790 remove_proc_subtree(de->name, de->parent);
791}
792EXPORT_SYMBOL(proc_remove);
793
794void *PDE_DATA(const struct inode *inode)
795{
796 return __PDE_DATA(inode);
797}
798EXPORT_SYMBOL(PDE_DATA);
799
800/*
801 * Pull a user buffer into memory and pass it to the file's write handler if
802 * one is supplied. The ->write() method is permitted to modify the
803 * kernel-side buffer.
804 */
805ssize_t proc_simple_write(struct file *f, const char __user *ubuf, size_t size,
806 loff_t *_pos)
807{
808 struct proc_dir_entry *pde = PDE(file_inode(f));
809 char *buf;
810 int ret;
811
812 if (!pde->write)
813 return -EACCES;
814 if (size == 0 || size > PAGE_SIZE - 1)
815 return -EINVAL;
816 buf = memdup_user_nul(ubuf, size);
817 if (IS_ERR(buf))
818 return PTR_ERR(buf);
819 ret = pde->write(f, buf, size);
820 kfree(buf);
821 return ret == 0 ? size : ret;
822}