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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/proc/inode.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 */
7
8#include <linux/cache.h>
9#include <linux/time.h>
10#include <linux/proc_fs.h>
11#include <linux/kernel.h>
12#include <linux/pid_namespace.h>
13#include <linux/mm.h>
14#include <linux/string.h>
15#include <linux/stat.h>
16#include <linux/completion.h>
17#include <linux/poll.h>
18#include <linux/printk.h>
19#include <linux/file.h>
20#include <linux/limits.h>
21#include <linux/init.h>
22#include <linux/module.h>
23#include <linux/sysctl.h>
24#include <linux/seq_file.h>
25#include <linux/slab.h>
26#include <linux/mount.h>
27#include <linux/bug.h>
28
29#include <linux/uaccess.h>
30
31#include "internal.h"
32
33static void proc_evict_inode(struct inode *inode)
34{
35 struct proc_dir_entry *de;
36 struct ctl_table_header *head;
37 struct proc_inode *ei = PROC_I(inode);
38
39 truncate_inode_pages_final(&inode->i_data);
40 clear_inode(inode);
41
42 /* Stop tracking associated processes */
43 if (ei->pid) {
44 proc_pid_evict_inode(ei);
45 ei->pid = NULL;
46 }
47
48 /* Let go of any associated proc directory entry */
49 de = ei->pde;
50 if (de) {
51 pde_put(de);
52 ei->pde = NULL;
53 }
54
55 head = ei->sysctl;
56 if (head) {
57 RCU_INIT_POINTER(ei->sysctl, NULL);
58 proc_sys_evict_inode(inode, head);
59 }
60}
61
62static struct kmem_cache *proc_inode_cachep __ro_after_init;
63static struct kmem_cache *pde_opener_cache __ro_after_init;
64
65static struct inode *proc_alloc_inode(struct super_block *sb)
66{
67 struct proc_inode *ei;
68
69 ei = kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
70 if (!ei)
71 return NULL;
72 ei->pid = NULL;
73 ei->fd = 0;
74 ei->op.proc_get_link = NULL;
75 ei->pde = NULL;
76 ei->sysctl = NULL;
77 ei->sysctl_entry = NULL;
78 INIT_HLIST_NODE(&ei->sibling_inodes);
79 ei->ns_ops = NULL;
80 return &ei->vfs_inode;
81}
82
83static void proc_free_inode(struct inode *inode)
84{
85 kmem_cache_free(proc_inode_cachep, PROC_I(inode));
86}
87
88static void init_once(void *foo)
89{
90 struct proc_inode *ei = (struct proc_inode *) foo;
91
92 inode_init_once(&ei->vfs_inode);
93}
94
95void __init proc_init_kmemcache(void)
96{
97 proc_inode_cachep = kmem_cache_create("proc_inode_cache",
98 sizeof(struct proc_inode),
99 0, (SLAB_RECLAIM_ACCOUNT|
100 SLAB_MEM_SPREAD|SLAB_ACCOUNT|
101 SLAB_PANIC),
102 init_once);
103 pde_opener_cache =
104 kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,
105 SLAB_ACCOUNT|SLAB_PANIC, NULL);
106 proc_dir_entry_cache = kmem_cache_create_usercopy(
107 "proc_dir_entry", SIZEOF_PDE, 0, SLAB_PANIC,
108 offsetof(struct proc_dir_entry, inline_name),
109 SIZEOF_PDE_INLINE_NAME, NULL);
110 BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);
111}
112
113void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock)
114{
115 struct inode *inode;
116 struct proc_inode *ei;
117 struct hlist_node *node;
118 struct super_block *old_sb = NULL;
119
120 rcu_read_lock();
121 for (;;) {
122 struct super_block *sb;
123 node = hlist_first_rcu(inodes);
124 if (!node)
125 break;
126 ei = hlist_entry(node, struct proc_inode, sibling_inodes);
127 spin_lock(lock);
128 hlist_del_init_rcu(&ei->sibling_inodes);
129 spin_unlock(lock);
130
131 inode = &ei->vfs_inode;
132 sb = inode->i_sb;
133 if ((sb != old_sb) && !atomic_inc_not_zero(&sb->s_active))
134 continue;
135 inode = igrab(inode);
136 rcu_read_unlock();
137 if (sb != old_sb) {
138 if (old_sb)
139 deactivate_super(old_sb);
140 old_sb = sb;
141 }
142 if (unlikely(!inode)) {
143 rcu_read_lock();
144 continue;
145 }
146
147 if (S_ISDIR(inode->i_mode)) {
148 struct dentry *dir = d_find_any_alias(inode);
149 if (dir) {
150 d_invalidate(dir);
151 dput(dir);
152 }
153 } else {
154 struct dentry *dentry;
155 while ((dentry = d_find_alias(inode))) {
156 d_invalidate(dentry);
157 dput(dentry);
158 }
159 }
160 iput(inode);
161
162 rcu_read_lock();
163 }
164 rcu_read_unlock();
165 if (old_sb)
166 deactivate_super(old_sb);
167}
168
169static inline const char *hidepid2str(enum proc_hidepid v)
170{
171 switch (v) {
172 case HIDEPID_OFF: return "off";
173 case HIDEPID_NO_ACCESS: return "noaccess";
174 case HIDEPID_INVISIBLE: return "invisible";
175 case HIDEPID_NOT_PTRACEABLE: return "ptraceable";
176 }
177 WARN_ONCE(1, "bad hide_pid value: %d\n", v);
178 return "unknown";
179}
180
181static int proc_show_options(struct seq_file *seq, struct dentry *root)
182{
183 struct proc_fs_info *fs_info = proc_sb_info(root->d_sb);
184
185 if (!gid_eq(fs_info->pid_gid, GLOBAL_ROOT_GID))
186 seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, fs_info->pid_gid));
187 if (fs_info->hide_pid != HIDEPID_OFF)
188 seq_printf(seq, ",hidepid=%s", hidepid2str(fs_info->hide_pid));
189 if (fs_info->pidonly != PROC_PIDONLY_OFF)
190 seq_printf(seq, ",subset=pid");
191
192 return 0;
193}
194
195const struct super_operations proc_sops = {
196 .alloc_inode = proc_alloc_inode,
197 .free_inode = proc_free_inode,
198 .drop_inode = generic_delete_inode,
199 .evict_inode = proc_evict_inode,
200 .statfs = simple_statfs,
201 .show_options = proc_show_options,
202};
203
204enum {BIAS = -1U<<31};
205
206static inline int use_pde(struct proc_dir_entry *pde)
207{
208 return likely(atomic_inc_unless_negative(&pde->in_use));
209}
210
211static void unuse_pde(struct proc_dir_entry *pde)
212{
213 if (unlikely(atomic_dec_return(&pde->in_use) == BIAS))
214 complete(pde->pde_unload_completion);
215}
216
217/* pde is locked on entry, unlocked on exit */
218static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
219 __releases(&pde->pde_unload_lock)
220{
221 /*
222 * close() (proc_reg_release()) can't delete an entry and proceed:
223 * ->release hook needs to be available at the right moment.
224 *
225 * rmmod (remove_proc_entry() et al) can't delete an entry and proceed:
226 * "struct file" needs to be available at the right moment.
227 *
228 * Therefore, first process to enter this function does ->release() and
229 * signals its completion to the other process which does nothing.
230 */
231 if (pdeo->closing) {
232 /* somebody else is doing that, just wait */
233 DECLARE_COMPLETION_ONSTACK(c);
234 pdeo->c = &c;
235 spin_unlock(&pde->pde_unload_lock);
236 wait_for_completion(&c);
237 } else {
238 struct file *file;
239 struct completion *c;
240
241 pdeo->closing = true;
242 spin_unlock(&pde->pde_unload_lock);
243 file = pdeo->file;
244 pde->proc_ops->proc_release(file_inode(file), file);
245 spin_lock(&pde->pde_unload_lock);
246 /* After ->release. */
247 list_del(&pdeo->lh);
248 c = pdeo->c;
249 spin_unlock(&pde->pde_unload_lock);
250 if (unlikely(c))
251 complete(c);
252 kmem_cache_free(pde_opener_cache, pdeo);
253 }
254}
255
256void proc_entry_rundown(struct proc_dir_entry *de)
257{
258 DECLARE_COMPLETION_ONSTACK(c);
259 /* Wait until all existing callers into module are done. */
260 de->pde_unload_completion = &c;
261 if (atomic_add_return(BIAS, &de->in_use) != BIAS)
262 wait_for_completion(&c);
263
264 /* ->pde_openers list can't grow from now on. */
265
266 spin_lock(&de->pde_unload_lock);
267 while (!list_empty(&de->pde_openers)) {
268 struct pde_opener *pdeo;
269 pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
270 close_pdeo(de, pdeo);
271 spin_lock(&de->pde_unload_lock);
272 }
273 spin_unlock(&de->pde_unload_lock);
274}
275
276static loff_t pde_lseek(struct proc_dir_entry *pde, struct file *file, loff_t offset, int whence)
277{
278 typeof_member(struct proc_ops, proc_lseek) lseek;
279
280 lseek = pde->proc_ops->proc_lseek;
281 if (!lseek)
282 lseek = default_llseek;
283 return lseek(file, offset, whence);
284}
285
286static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
287{
288 struct proc_dir_entry *pde = PDE(file_inode(file));
289 loff_t rv = -EINVAL;
290
291 if (pde_is_permanent(pde)) {
292 return pde_lseek(pde, file, offset, whence);
293 } else if (use_pde(pde)) {
294 rv = pde_lseek(pde, file, offset, whence);
295 unuse_pde(pde);
296 }
297 return rv;
298}
299
300static ssize_t pde_read(struct proc_dir_entry *pde, struct file *file, char __user *buf, size_t count, loff_t *ppos)
301{
302 typeof_member(struct proc_ops, proc_read) read;
303
304 read = pde->proc_ops->proc_read;
305 if (read)
306 return read(file, buf, count, ppos);
307 return -EIO;
308}
309
310static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
311{
312 struct proc_dir_entry *pde = PDE(file_inode(file));
313 ssize_t rv = -EIO;
314
315 if (pde_is_permanent(pde)) {
316 return pde_read(pde, file, buf, count, ppos);
317 } else if (use_pde(pde)) {
318 rv = pde_read(pde, file, buf, count, ppos);
319 unuse_pde(pde);
320 }
321 return rv;
322}
323
324static ssize_t pde_write(struct proc_dir_entry *pde, struct file *file, const char __user *buf, size_t count, loff_t *ppos)
325{
326 typeof_member(struct proc_ops, proc_write) write;
327
328 write = pde->proc_ops->proc_write;
329 if (write)
330 return write(file, buf, count, ppos);
331 return -EIO;
332}
333
334static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
335{
336 struct proc_dir_entry *pde = PDE(file_inode(file));
337 ssize_t rv = -EIO;
338
339 if (pde_is_permanent(pde)) {
340 return pde_write(pde, file, buf, count, ppos);
341 } else if (use_pde(pde)) {
342 rv = pde_write(pde, file, buf, count, ppos);
343 unuse_pde(pde);
344 }
345 return rv;
346}
347
348static __poll_t pde_poll(struct proc_dir_entry *pde, struct file *file, struct poll_table_struct *pts)
349{
350 typeof_member(struct proc_ops, proc_poll) poll;
351
352 poll = pde->proc_ops->proc_poll;
353 if (poll)
354 return poll(file, pts);
355 return DEFAULT_POLLMASK;
356}
357
358static __poll_t proc_reg_poll(struct file *file, struct poll_table_struct *pts)
359{
360 struct proc_dir_entry *pde = PDE(file_inode(file));
361 __poll_t rv = DEFAULT_POLLMASK;
362
363 if (pde_is_permanent(pde)) {
364 return pde_poll(pde, file, pts);
365 } else if (use_pde(pde)) {
366 rv = pde_poll(pde, file, pts);
367 unuse_pde(pde);
368 }
369 return rv;
370}
371
372static long pde_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
373{
374 typeof_member(struct proc_ops, proc_ioctl) ioctl;
375
376 ioctl = pde->proc_ops->proc_ioctl;
377 if (ioctl)
378 return ioctl(file, cmd, arg);
379 return -ENOTTY;
380}
381
382static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
383{
384 struct proc_dir_entry *pde = PDE(file_inode(file));
385 long rv = -ENOTTY;
386
387 if (pde_is_permanent(pde)) {
388 return pde_ioctl(pde, file, cmd, arg);
389 } else if (use_pde(pde)) {
390 rv = pde_ioctl(pde, file, cmd, arg);
391 unuse_pde(pde);
392 }
393 return rv;
394}
395
396#ifdef CONFIG_COMPAT
397static long pde_compat_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
398{
399 typeof_member(struct proc_ops, proc_compat_ioctl) compat_ioctl;
400
401 compat_ioctl = pde->proc_ops->proc_compat_ioctl;
402 if (compat_ioctl)
403 return compat_ioctl(file, cmd, arg);
404 return -ENOTTY;
405}
406
407static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
408{
409 struct proc_dir_entry *pde = PDE(file_inode(file));
410 long rv = -ENOTTY;
411 if (pde_is_permanent(pde)) {
412 return pde_compat_ioctl(pde, file, cmd, arg);
413 } else if (use_pde(pde)) {
414 rv = pde_compat_ioctl(pde, file, cmd, arg);
415 unuse_pde(pde);
416 }
417 return rv;
418}
419#endif
420
421static int pde_mmap(struct proc_dir_entry *pde, struct file *file, struct vm_area_struct *vma)
422{
423 typeof_member(struct proc_ops, proc_mmap) mmap;
424
425 mmap = pde->proc_ops->proc_mmap;
426 if (mmap)
427 return mmap(file, vma);
428 return -EIO;
429}
430
431static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
432{
433 struct proc_dir_entry *pde = PDE(file_inode(file));
434 int rv = -EIO;
435
436 if (pde_is_permanent(pde)) {
437 return pde_mmap(pde, file, vma);
438 } else if (use_pde(pde)) {
439 rv = pde_mmap(pde, file, vma);
440 unuse_pde(pde);
441 }
442 return rv;
443}
444
445static unsigned long
446pde_get_unmapped_area(struct proc_dir_entry *pde, struct file *file, unsigned long orig_addr,
447 unsigned long len, unsigned long pgoff,
448 unsigned long flags)
449{
450 typeof_member(struct proc_ops, proc_get_unmapped_area) get_area;
451
452 get_area = pde->proc_ops->proc_get_unmapped_area;
453#ifdef CONFIG_MMU
454 if (!get_area)
455 get_area = current->mm->get_unmapped_area;
456#endif
457 if (get_area)
458 return get_area(file, orig_addr, len, pgoff, flags);
459 return orig_addr;
460}
461
462static unsigned long
463proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
464 unsigned long len, unsigned long pgoff,
465 unsigned long flags)
466{
467 struct proc_dir_entry *pde = PDE(file_inode(file));
468 unsigned long rv = -EIO;
469
470 if (pde_is_permanent(pde)) {
471 return pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);
472 } else if (use_pde(pde)) {
473 rv = pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);
474 unuse_pde(pde);
475 }
476 return rv;
477}
478
479static int proc_reg_open(struct inode *inode, struct file *file)
480{
481 struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
482 struct proc_dir_entry *pde = PDE(inode);
483 int rv = 0;
484 typeof_member(struct proc_ops, proc_open) open;
485 typeof_member(struct proc_ops, proc_release) release;
486 struct pde_opener *pdeo;
487
488 if (pde_is_permanent(pde)) {
489 open = pde->proc_ops->proc_open;
490 if (open)
491 rv = open(inode, file);
492 return rv;
493 }
494
495 if (fs_info->pidonly == PROC_PIDONLY_ON)
496 return -ENOENT;
497
498 /*
499 * Ensure that
500 * 1) PDE's ->release hook will be called no matter what
501 * either normally by close()/->release, or forcefully by
502 * rmmod/remove_proc_entry.
503 *
504 * 2) rmmod isn't blocked by opening file in /proc and sitting on
505 * the descriptor (including "rmmod foo </proc/foo" scenario).
506 *
507 * Save every "struct file" with custom ->release hook.
508 */
509 if (!use_pde(pde))
510 return -ENOENT;
511
512 release = pde->proc_ops->proc_release;
513 if (release) {
514 pdeo = kmem_cache_alloc(pde_opener_cache, GFP_KERNEL);
515 if (!pdeo) {
516 rv = -ENOMEM;
517 goto out_unuse;
518 }
519 }
520
521 open = pde->proc_ops->proc_open;
522 if (open)
523 rv = open(inode, file);
524
525 if (release) {
526 if (rv == 0) {
527 /* To know what to release. */
528 pdeo->file = file;
529 pdeo->closing = false;
530 pdeo->c = NULL;
531 spin_lock(&pde->pde_unload_lock);
532 list_add(&pdeo->lh, &pde->pde_openers);
533 spin_unlock(&pde->pde_unload_lock);
534 } else
535 kmem_cache_free(pde_opener_cache, pdeo);
536 }
537
538out_unuse:
539 unuse_pde(pde);
540 return rv;
541}
542
543static int proc_reg_release(struct inode *inode, struct file *file)
544{
545 struct proc_dir_entry *pde = PDE(inode);
546 struct pde_opener *pdeo;
547
548 if (pde_is_permanent(pde)) {
549 typeof_member(struct proc_ops, proc_release) release;
550
551 release = pde->proc_ops->proc_release;
552 if (release) {
553 return release(inode, file);
554 }
555 return 0;
556 }
557
558 spin_lock(&pde->pde_unload_lock);
559 list_for_each_entry(pdeo, &pde->pde_openers, lh) {
560 if (pdeo->file == file) {
561 close_pdeo(pde, pdeo);
562 return 0;
563 }
564 }
565 spin_unlock(&pde->pde_unload_lock);
566 return 0;
567}
568
569static const struct file_operations proc_reg_file_ops = {
570 .llseek = proc_reg_llseek,
571 .read = proc_reg_read,
572 .write = proc_reg_write,
573 .poll = proc_reg_poll,
574 .unlocked_ioctl = proc_reg_unlocked_ioctl,
575#ifdef CONFIG_COMPAT
576 .compat_ioctl = proc_reg_compat_ioctl,
577#endif
578 .mmap = proc_reg_mmap,
579 .get_unmapped_area = proc_reg_get_unmapped_area,
580 .open = proc_reg_open,
581 .release = proc_reg_release,
582};
583
584#ifdef CONFIG_COMPAT
585static const struct file_operations proc_reg_file_ops_no_compat = {
586 .llseek = proc_reg_llseek,
587 .read = proc_reg_read,
588 .write = proc_reg_write,
589 .poll = proc_reg_poll,
590 .unlocked_ioctl = proc_reg_unlocked_ioctl,
591 .mmap = proc_reg_mmap,
592 .get_unmapped_area = proc_reg_get_unmapped_area,
593 .open = proc_reg_open,
594 .release = proc_reg_release,
595};
596#endif
597
598static void proc_put_link(void *p)
599{
600 unuse_pde(p);
601}
602
603static const char *proc_get_link(struct dentry *dentry,
604 struct inode *inode,
605 struct delayed_call *done)
606{
607 struct proc_dir_entry *pde = PDE(inode);
608 if (!use_pde(pde))
609 return ERR_PTR(-EINVAL);
610 set_delayed_call(done, proc_put_link, pde);
611 return pde->data;
612}
613
614const struct inode_operations proc_link_inode_operations = {
615 .get_link = proc_get_link,
616};
617
618struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
619{
620 struct inode *inode = new_inode(sb);
621
622 if (inode) {
623 inode->i_ino = de->low_ino;
624 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
625 PROC_I(inode)->pde = de;
626
627 if (is_empty_pde(de)) {
628 make_empty_dir_inode(inode);
629 return inode;
630 }
631 if (de->mode) {
632 inode->i_mode = de->mode;
633 inode->i_uid = de->uid;
634 inode->i_gid = de->gid;
635 }
636 if (de->size)
637 inode->i_size = de->size;
638 if (de->nlink)
639 set_nlink(inode, de->nlink);
640
641 if (S_ISREG(inode->i_mode)) {
642 inode->i_op = de->proc_iops;
643 inode->i_fop = &proc_reg_file_ops;
644#ifdef CONFIG_COMPAT
645 if (!de->proc_ops->proc_compat_ioctl) {
646 inode->i_fop = &proc_reg_file_ops_no_compat;
647 }
648#endif
649 } else if (S_ISDIR(inode->i_mode)) {
650 inode->i_op = de->proc_iops;
651 inode->i_fop = de->proc_dir_ops;
652 } else if (S_ISLNK(inode->i_mode)) {
653 inode->i_op = de->proc_iops;
654 inode->i_fop = NULL;
655 } else
656 BUG();
657 } else
658 pde_put(de);
659 return inode;
660}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/proc/inode.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 */
7
8#include <linux/cache.h>
9#include <linux/time.h>
10#include <linux/proc_fs.h>
11#include <linux/kernel.h>
12#include <linux/pid_namespace.h>
13#include <linux/mm.h>
14#include <linux/string.h>
15#include <linux/stat.h>
16#include <linux/completion.h>
17#include <linux/poll.h>
18#include <linux/printk.h>
19#include <linux/file.h>
20#include <linux/limits.h>
21#include <linux/init.h>
22#include <linux/module.h>
23#include <linux/sysctl.h>
24#include <linux/seq_file.h>
25#include <linux/slab.h>
26#include <linux/mount.h>
27
28#include <linux/uaccess.h>
29
30#include "internal.h"
31
32static void proc_evict_inode(struct inode *inode)
33{
34 struct proc_dir_entry *de;
35 struct ctl_table_header *head;
36
37 truncate_inode_pages_final(&inode->i_data);
38 clear_inode(inode);
39
40 /* Stop tracking associated processes */
41 put_pid(PROC_I(inode)->pid);
42
43 /* Let go of any associated proc directory entry */
44 de = PDE(inode);
45 if (de)
46 pde_put(de);
47
48 head = PROC_I(inode)->sysctl;
49 if (head) {
50 RCU_INIT_POINTER(PROC_I(inode)->sysctl, NULL);
51 proc_sys_evict_inode(inode, head);
52 }
53}
54
55static struct kmem_cache *proc_inode_cachep __ro_after_init;
56static struct kmem_cache *pde_opener_cache __ro_after_init;
57
58static struct inode *proc_alloc_inode(struct super_block *sb)
59{
60 struct proc_inode *ei;
61
62 ei = kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);
63 if (!ei)
64 return NULL;
65 ei->pid = NULL;
66 ei->fd = 0;
67 ei->op.proc_get_link = NULL;
68 ei->pde = NULL;
69 ei->sysctl = NULL;
70 ei->sysctl_entry = NULL;
71 ei->ns_ops = NULL;
72 return &ei->vfs_inode;
73}
74
75static void proc_free_inode(struct inode *inode)
76{
77 kmem_cache_free(proc_inode_cachep, PROC_I(inode));
78}
79
80static void init_once(void *foo)
81{
82 struct proc_inode *ei = (struct proc_inode *) foo;
83
84 inode_init_once(&ei->vfs_inode);
85}
86
87void __init proc_init_kmemcache(void)
88{
89 proc_inode_cachep = kmem_cache_create("proc_inode_cache",
90 sizeof(struct proc_inode),
91 0, (SLAB_RECLAIM_ACCOUNT|
92 SLAB_MEM_SPREAD|SLAB_ACCOUNT|
93 SLAB_PANIC),
94 init_once);
95 pde_opener_cache =
96 kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,
97 SLAB_ACCOUNT|SLAB_PANIC, NULL);
98 proc_dir_entry_cache = kmem_cache_create_usercopy(
99 "proc_dir_entry", SIZEOF_PDE, 0, SLAB_PANIC,
100 offsetof(struct proc_dir_entry, inline_name),
101 SIZEOF_PDE_INLINE_NAME, NULL);
102 BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);
103}
104
105static int proc_show_options(struct seq_file *seq, struct dentry *root)
106{
107 struct super_block *sb = root->d_sb;
108 struct pid_namespace *pid = sb->s_fs_info;
109
110 if (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID))
111 seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, pid->pid_gid));
112 if (pid->hide_pid != HIDEPID_OFF)
113 seq_printf(seq, ",hidepid=%u", pid->hide_pid);
114
115 return 0;
116}
117
118const struct super_operations proc_sops = {
119 .alloc_inode = proc_alloc_inode,
120 .free_inode = proc_free_inode,
121 .drop_inode = generic_delete_inode,
122 .evict_inode = proc_evict_inode,
123 .statfs = simple_statfs,
124 .show_options = proc_show_options,
125};
126
127enum {BIAS = -1U<<31};
128
129static inline int use_pde(struct proc_dir_entry *pde)
130{
131 return likely(atomic_inc_unless_negative(&pde->in_use));
132}
133
134static void unuse_pde(struct proc_dir_entry *pde)
135{
136 if (unlikely(atomic_dec_return(&pde->in_use) == BIAS))
137 complete(pde->pde_unload_completion);
138}
139
140/* pde is locked on entry, unlocked on exit */
141static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
142{
143 /*
144 * close() (proc_reg_release()) can't delete an entry and proceed:
145 * ->release hook needs to be available at the right moment.
146 *
147 * rmmod (remove_proc_entry() et al) can't delete an entry and proceed:
148 * "struct file" needs to be available at the right moment.
149 *
150 * Therefore, first process to enter this function does ->release() and
151 * signals its completion to the other process which does nothing.
152 */
153 if (pdeo->closing) {
154 /* somebody else is doing that, just wait */
155 DECLARE_COMPLETION_ONSTACK(c);
156 pdeo->c = &c;
157 spin_unlock(&pde->pde_unload_lock);
158 wait_for_completion(&c);
159 } else {
160 struct file *file;
161 struct completion *c;
162
163 pdeo->closing = true;
164 spin_unlock(&pde->pde_unload_lock);
165 file = pdeo->file;
166 pde->proc_fops->release(file_inode(file), file);
167 spin_lock(&pde->pde_unload_lock);
168 /* After ->release. */
169 list_del(&pdeo->lh);
170 c = pdeo->c;
171 spin_unlock(&pde->pde_unload_lock);
172 if (unlikely(c))
173 complete(c);
174 kmem_cache_free(pde_opener_cache, pdeo);
175 }
176}
177
178void proc_entry_rundown(struct proc_dir_entry *de)
179{
180 DECLARE_COMPLETION_ONSTACK(c);
181 /* Wait until all existing callers into module are done. */
182 de->pde_unload_completion = &c;
183 if (atomic_add_return(BIAS, &de->in_use) != BIAS)
184 wait_for_completion(&c);
185
186 /* ->pde_openers list can't grow from now on. */
187
188 spin_lock(&de->pde_unload_lock);
189 while (!list_empty(&de->pde_openers)) {
190 struct pde_opener *pdeo;
191 pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
192 close_pdeo(de, pdeo);
193 spin_lock(&de->pde_unload_lock);
194 }
195 spin_unlock(&de->pde_unload_lock);
196}
197
198static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
199{
200 struct proc_dir_entry *pde = PDE(file_inode(file));
201 loff_t rv = -EINVAL;
202 if (use_pde(pde)) {
203 typeof_member(struct file_operations, llseek) llseek;
204
205 llseek = pde->proc_fops->llseek;
206 if (!llseek)
207 llseek = default_llseek;
208 rv = llseek(file, offset, whence);
209 unuse_pde(pde);
210 }
211 return rv;
212}
213
214static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
215{
216 struct proc_dir_entry *pde = PDE(file_inode(file));
217 ssize_t rv = -EIO;
218 if (use_pde(pde)) {
219 typeof_member(struct file_operations, read) read;
220
221 read = pde->proc_fops->read;
222 if (read)
223 rv = read(file, buf, count, ppos);
224 unuse_pde(pde);
225 }
226 return rv;
227}
228
229static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
230{
231 struct proc_dir_entry *pde = PDE(file_inode(file));
232 ssize_t rv = -EIO;
233 if (use_pde(pde)) {
234 typeof_member(struct file_operations, write) write;
235
236 write = pde->proc_fops->write;
237 if (write)
238 rv = write(file, buf, count, ppos);
239 unuse_pde(pde);
240 }
241 return rv;
242}
243
244static __poll_t proc_reg_poll(struct file *file, struct poll_table_struct *pts)
245{
246 struct proc_dir_entry *pde = PDE(file_inode(file));
247 __poll_t rv = DEFAULT_POLLMASK;
248 if (use_pde(pde)) {
249 typeof_member(struct file_operations, poll) poll;
250
251 poll = pde->proc_fops->poll;
252 if (poll)
253 rv = poll(file, pts);
254 unuse_pde(pde);
255 }
256 return rv;
257}
258
259static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
260{
261 struct proc_dir_entry *pde = PDE(file_inode(file));
262 long rv = -ENOTTY;
263 if (use_pde(pde)) {
264 typeof_member(struct file_operations, unlocked_ioctl) ioctl;
265
266 ioctl = pde->proc_fops->unlocked_ioctl;
267 if (ioctl)
268 rv = ioctl(file, cmd, arg);
269 unuse_pde(pde);
270 }
271 return rv;
272}
273
274#ifdef CONFIG_COMPAT
275static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
276{
277 struct proc_dir_entry *pde = PDE(file_inode(file));
278 long rv = -ENOTTY;
279 if (use_pde(pde)) {
280 typeof_member(struct file_operations, compat_ioctl) compat_ioctl;
281
282 compat_ioctl = pde->proc_fops->compat_ioctl;
283 if (compat_ioctl)
284 rv = compat_ioctl(file, cmd, arg);
285 unuse_pde(pde);
286 }
287 return rv;
288}
289#endif
290
291static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
292{
293 struct proc_dir_entry *pde = PDE(file_inode(file));
294 int rv = -EIO;
295 if (use_pde(pde)) {
296 typeof_member(struct file_operations, mmap) mmap;
297
298 mmap = pde->proc_fops->mmap;
299 if (mmap)
300 rv = mmap(file, vma);
301 unuse_pde(pde);
302 }
303 return rv;
304}
305
306static unsigned long
307proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
308 unsigned long len, unsigned long pgoff,
309 unsigned long flags)
310{
311 struct proc_dir_entry *pde = PDE(file_inode(file));
312 unsigned long rv = -EIO;
313
314 if (use_pde(pde)) {
315 typeof_member(struct file_operations, get_unmapped_area) get_area;
316
317 get_area = pde->proc_fops->get_unmapped_area;
318#ifdef CONFIG_MMU
319 if (!get_area)
320 get_area = current->mm->get_unmapped_area;
321#endif
322
323 if (get_area)
324 rv = get_area(file, orig_addr, len, pgoff, flags);
325 else
326 rv = orig_addr;
327 unuse_pde(pde);
328 }
329 return rv;
330}
331
332static int proc_reg_open(struct inode *inode, struct file *file)
333{
334 struct proc_dir_entry *pde = PDE(inode);
335 int rv = 0;
336 typeof_member(struct file_operations, open) open;
337 typeof_member(struct file_operations, release) release;
338 struct pde_opener *pdeo;
339
340 /*
341 * Ensure that
342 * 1) PDE's ->release hook will be called no matter what
343 * either normally by close()/->release, or forcefully by
344 * rmmod/remove_proc_entry.
345 *
346 * 2) rmmod isn't blocked by opening file in /proc and sitting on
347 * the descriptor (including "rmmod foo </proc/foo" scenario).
348 *
349 * Save every "struct file" with custom ->release hook.
350 */
351 if (!use_pde(pde))
352 return -ENOENT;
353
354 release = pde->proc_fops->release;
355 if (release) {
356 pdeo = kmem_cache_alloc(pde_opener_cache, GFP_KERNEL);
357 if (!pdeo) {
358 rv = -ENOMEM;
359 goto out_unuse;
360 }
361 }
362
363 open = pde->proc_fops->open;
364 if (open)
365 rv = open(inode, file);
366
367 if (release) {
368 if (rv == 0) {
369 /* To know what to release. */
370 pdeo->file = file;
371 pdeo->closing = false;
372 pdeo->c = NULL;
373 spin_lock(&pde->pde_unload_lock);
374 list_add(&pdeo->lh, &pde->pde_openers);
375 spin_unlock(&pde->pde_unload_lock);
376 } else
377 kmem_cache_free(pde_opener_cache, pdeo);
378 }
379
380out_unuse:
381 unuse_pde(pde);
382 return rv;
383}
384
385static int proc_reg_release(struct inode *inode, struct file *file)
386{
387 struct proc_dir_entry *pde = PDE(inode);
388 struct pde_opener *pdeo;
389 spin_lock(&pde->pde_unload_lock);
390 list_for_each_entry(pdeo, &pde->pde_openers, lh) {
391 if (pdeo->file == file) {
392 close_pdeo(pde, pdeo);
393 return 0;
394 }
395 }
396 spin_unlock(&pde->pde_unload_lock);
397 return 0;
398}
399
400static const struct file_operations proc_reg_file_ops = {
401 .llseek = proc_reg_llseek,
402 .read = proc_reg_read,
403 .write = proc_reg_write,
404 .poll = proc_reg_poll,
405 .unlocked_ioctl = proc_reg_unlocked_ioctl,
406#ifdef CONFIG_COMPAT
407 .compat_ioctl = proc_reg_compat_ioctl,
408#endif
409 .mmap = proc_reg_mmap,
410 .get_unmapped_area = proc_reg_get_unmapped_area,
411 .open = proc_reg_open,
412 .release = proc_reg_release,
413};
414
415#ifdef CONFIG_COMPAT
416static const struct file_operations proc_reg_file_ops_no_compat = {
417 .llseek = proc_reg_llseek,
418 .read = proc_reg_read,
419 .write = proc_reg_write,
420 .poll = proc_reg_poll,
421 .unlocked_ioctl = proc_reg_unlocked_ioctl,
422 .mmap = proc_reg_mmap,
423 .get_unmapped_area = proc_reg_get_unmapped_area,
424 .open = proc_reg_open,
425 .release = proc_reg_release,
426};
427#endif
428
429static void proc_put_link(void *p)
430{
431 unuse_pde(p);
432}
433
434static const char *proc_get_link(struct dentry *dentry,
435 struct inode *inode,
436 struct delayed_call *done)
437{
438 struct proc_dir_entry *pde = PDE(inode);
439 if (!use_pde(pde))
440 return ERR_PTR(-EINVAL);
441 set_delayed_call(done, proc_put_link, pde);
442 return pde->data;
443}
444
445const struct inode_operations proc_link_inode_operations = {
446 .get_link = proc_get_link,
447};
448
449struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
450{
451 struct inode *inode = new_inode_pseudo(sb);
452
453 if (inode) {
454 inode->i_ino = de->low_ino;
455 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
456 PROC_I(inode)->pde = de;
457
458 if (is_empty_pde(de)) {
459 make_empty_dir_inode(inode);
460 return inode;
461 }
462 if (de->mode) {
463 inode->i_mode = de->mode;
464 inode->i_uid = de->uid;
465 inode->i_gid = de->gid;
466 }
467 if (de->size)
468 inode->i_size = de->size;
469 if (de->nlink)
470 set_nlink(inode, de->nlink);
471 WARN_ON(!de->proc_iops);
472 inode->i_op = de->proc_iops;
473 if (de->proc_fops) {
474 if (S_ISREG(inode->i_mode)) {
475#ifdef CONFIG_COMPAT
476 if (!de->proc_fops->compat_ioctl)
477 inode->i_fop =
478 &proc_reg_file_ops_no_compat;
479 else
480#endif
481 inode->i_fop = &proc_reg_file_ops;
482 } else {
483 inode->i_fop = de->proc_fops;
484 }
485 }
486 } else
487 pde_put(de);
488 return inode;
489}