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
proc_evict_inode(struct inode * inode)33 static 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
62 static struct kmem_cache *proc_inode_cachep __ro_after_init;
63 static struct kmem_cache *pde_opener_cache __ro_after_init;
64
proc_alloc_inode(struct super_block * sb)65 static 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
proc_free_inode(struct inode * inode)83 static void proc_free_inode(struct inode *inode)
84 {
85 kmem_cache_free(proc_inode_cachep, PROC_I(inode));
86 }
87
init_once(void * foo)88 static 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
proc_init_kmemcache(void)95 void __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
proc_invalidate_siblings_dcache(struct hlist_head * inodes,spinlock_t * lock)113 void 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
hidepid2str(enum proc_hidepid v)169 static 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
proc_show_options(struct seq_file * seq,struct dentry * root)181 static 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
195 const 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
204 enum {BIAS = -1U<<31};
205
use_pde(struct proc_dir_entry * pde)206 static inline int use_pde(struct proc_dir_entry *pde)
207 {
208 return likely(atomic_inc_unless_negative(&pde->in_use));
209 }
210
unuse_pde(struct proc_dir_entry * pde)211 static 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 */
close_pdeo(struct proc_dir_entry * pde,struct pde_opener * pdeo)218 static 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
proc_entry_rundown(struct proc_dir_entry * de)256 void 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
pde_lseek(struct proc_dir_entry * pde,struct file * file,loff_t offset,int whence)276 static 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
proc_reg_llseek(struct file * file,loff_t offset,int whence)286 static 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
proc_reg_read_iter(struct kiocb * iocb,struct iov_iter * iter)300 static ssize_t proc_reg_read_iter(struct kiocb *iocb, struct iov_iter *iter)
301 {
302 struct proc_dir_entry *pde = PDE(file_inode(iocb->ki_filp));
303 ssize_t ret;
304
305 if (pde_is_permanent(pde))
306 return pde->proc_ops->proc_read_iter(iocb, iter);
307
308 if (!use_pde(pde))
309 return -EIO;
310 ret = pde->proc_ops->proc_read_iter(iocb, iter);
311 unuse_pde(pde);
312 return ret;
313 }
314
pde_read(struct proc_dir_entry * pde,struct file * file,char __user * buf,size_t count,loff_t * ppos)315 static ssize_t pde_read(struct proc_dir_entry *pde, struct file *file, char __user *buf, size_t count, loff_t *ppos)
316 {
317 typeof_member(struct proc_ops, proc_read) read;
318
319 read = pde->proc_ops->proc_read;
320 if (read)
321 return read(file, buf, count, ppos);
322 return -EIO;
323 }
324
proc_reg_read(struct file * file,char __user * buf,size_t count,loff_t * ppos)325 static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
326 {
327 struct proc_dir_entry *pde = PDE(file_inode(file));
328 ssize_t rv = -EIO;
329
330 if (pde_is_permanent(pde)) {
331 return pde_read(pde, file, buf, count, ppos);
332 } else if (use_pde(pde)) {
333 rv = pde_read(pde, file, buf, count, ppos);
334 unuse_pde(pde);
335 }
336 return rv;
337 }
338
pde_write(struct proc_dir_entry * pde,struct file * file,const char __user * buf,size_t count,loff_t * ppos)339 static ssize_t pde_write(struct proc_dir_entry *pde, struct file *file, const char __user *buf, size_t count, loff_t *ppos)
340 {
341 typeof_member(struct proc_ops, proc_write) write;
342
343 write = pde->proc_ops->proc_write;
344 if (write)
345 return write(file, buf, count, ppos);
346 return -EIO;
347 }
348
proc_reg_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)349 static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
350 {
351 struct proc_dir_entry *pde = PDE(file_inode(file));
352 ssize_t rv = -EIO;
353
354 if (pde_is_permanent(pde)) {
355 return pde_write(pde, file, buf, count, ppos);
356 } else if (use_pde(pde)) {
357 rv = pde_write(pde, file, buf, count, ppos);
358 unuse_pde(pde);
359 }
360 return rv;
361 }
362
pde_poll(struct proc_dir_entry * pde,struct file * file,struct poll_table_struct * pts)363 static __poll_t pde_poll(struct proc_dir_entry *pde, struct file *file, struct poll_table_struct *pts)
364 {
365 typeof_member(struct proc_ops, proc_poll) poll;
366
367 poll = pde->proc_ops->proc_poll;
368 if (poll)
369 return poll(file, pts);
370 return DEFAULT_POLLMASK;
371 }
372
proc_reg_poll(struct file * file,struct poll_table_struct * pts)373 static __poll_t proc_reg_poll(struct file *file, struct poll_table_struct *pts)
374 {
375 struct proc_dir_entry *pde = PDE(file_inode(file));
376 __poll_t rv = DEFAULT_POLLMASK;
377
378 if (pde_is_permanent(pde)) {
379 return pde_poll(pde, file, pts);
380 } else if (use_pde(pde)) {
381 rv = pde_poll(pde, file, pts);
382 unuse_pde(pde);
383 }
384 return rv;
385 }
386
pde_ioctl(struct proc_dir_entry * pde,struct file * file,unsigned int cmd,unsigned long arg)387 static long pde_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
388 {
389 typeof_member(struct proc_ops, proc_ioctl) ioctl;
390
391 ioctl = pde->proc_ops->proc_ioctl;
392 if (ioctl)
393 return ioctl(file, cmd, arg);
394 return -ENOTTY;
395 }
396
proc_reg_unlocked_ioctl(struct file * file,unsigned int cmd,unsigned long arg)397 static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
398 {
399 struct proc_dir_entry *pde = PDE(file_inode(file));
400 long rv = -ENOTTY;
401
402 if (pde_is_permanent(pde)) {
403 return pde_ioctl(pde, file, cmd, arg);
404 } else if (use_pde(pde)) {
405 rv = pde_ioctl(pde, file, cmd, arg);
406 unuse_pde(pde);
407 }
408 return rv;
409 }
410
411 #ifdef CONFIG_COMPAT
pde_compat_ioctl(struct proc_dir_entry * pde,struct file * file,unsigned int cmd,unsigned long arg)412 static long pde_compat_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
413 {
414 typeof_member(struct proc_ops, proc_compat_ioctl) compat_ioctl;
415
416 compat_ioctl = pde->proc_ops->proc_compat_ioctl;
417 if (compat_ioctl)
418 return compat_ioctl(file, cmd, arg);
419 return -ENOTTY;
420 }
421
proc_reg_compat_ioctl(struct file * file,unsigned int cmd,unsigned long arg)422 static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
423 {
424 struct proc_dir_entry *pde = PDE(file_inode(file));
425 long rv = -ENOTTY;
426 if (pde_is_permanent(pde)) {
427 return pde_compat_ioctl(pde, file, cmd, arg);
428 } else if (use_pde(pde)) {
429 rv = pde_compat_ioctl(pde, file, cmd, arg);
430 unuse_pde(pde);
431 }
432 return rv;
433 }
434 #endif
435
pde_mmap(struct proc_dir_entry * pde,struct file * file,struct vm_area_struct * vma)436 static int pde_mmap(struct proc_dir_entry *pde, struct file *file, struct vm_area_struct *vma)
437 {
438 typeof_member(struct proc_ops, proc_mmap) mmap;
439
440 mmap = pde->proc_ops->proc_mmap;
441 if (mmap)
442 return mmap(file, vma);
443 return -EIO;
444 }
445
proc_reg_mmap(struct file * file,struct vm_area_struct * vma)446 static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
447 {
448 struct proc_dir_entry *pde = PDE(file_inode(file));
449 int rv = -EIO;
450
451 if (pde_is_permanent(pde)) {
452 return pde_mmap(pde, file, vma);
453 } else if (use_pde(pde)) {
454 rv = pde_mmap(pde, file, vma);
455 unuse_pde(pde);
456 }
457 return rv;
458 }
459
460 static unsigned long
pde_get_unmapped_area(struct proc_dir_entry * pde,struct file * file,unsigned long orig_addr,unsigned long len,unsigned long pgoff,unsigned long flags)461 pde_get_unmapped_area(struct proc_dir_entry *pde, struct file *file, unsigned long orig_addr,
462 unsigned long len, unsigned long pgoff,
463 unsigned long flags)
464 {
465 typeof_member(struct proc_ops, proc_get_unmapped_area) get_area;
466
467 get_area = pde->proc_ops->proc_get_unmapped_area;
468 #ifdef CONFIG_MMU
469 if (!get_area)
470 get_area = current->mm->get_unmapped_area;
471 #endif
472 if (get_area)
473 return get_area(file, orig_addr, len, pgoff, flags);
474 return orig_addr;
475 }
476
477 static unsigned long
proc_reg_get_unmapped_area(struct file * file,unsigned long orig_addr,unsigned long len,unsigned long pgoff,unsigned long flags)478 proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
479 unsigned long len, unsigned long pgoff,
480 unsigned long flags)
481 {
482 struct proc_dir_entry *pde = PDE(file_inode(file));
483 unsigned long rv = -EIO;
484
485 if (pde_is_permanent(pde)) {
486 return pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);
487 } else if (use_pde(pde)) {
488 rv = pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);
489 unuse_pde(pde);
490 }
491 return rv;
492 }
493
proc_reg_open(struct inode * inode,struct file * file)494 static int proc_reg_open(struct inode *inode, struct file *file)
495 {
496 struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);
497 struct proc_dir_entry *pde = PDE(inode);
498 int rv = 0;
499 typeof_member(struct proc_ops, proc_open) open;
500 typeof_member(struct proc_ops, proc_release) release;
501 struct pde_opener *pdeo;
502
503 if (pde_is_permanent(pde)) {
504 open = pde->proc_ops->proc_open;
505 if (open)
506 rv = open(inode, file);
507 return rv;
508 }
509
510 if (fs_info->pidonly == PROC_PIDONLY_ON)
511 return -ENOENT;
512
513 /*
514 * Ensure that
515 * 1) PDE's ->release hook will be called no matter what
516 * either normally by close()/->release, or forcefully by
517 * rmmod/remove_proc_entry.
518 *
519 * 2) rmmod isn't blocked by opening file in /proc and sitting on
520 * the descriptor (including "rmmod foo </proc/foo" scenario).
521 *
522 * Save every "struct file" with custom ->release hook.
523 */
524 if (!use_pde(pde))
525 return -ENOENT;
526
527 release = pde->proc_ops->proc_release;
528 if (release) {
529 pdeo = kmem_cache_alloc(pde_opener_cache, GFP_KERNEL);
530 if (!pdeo) {
531 rv = -ENOMEM;
532 goto out_unuse;
533 }
534 }
535
536 open = pde->proc_ops->proc_open;
537 if (open)
538 rv = open(inode, file);
539
540 if (release) {
541 if (rv == 0) {
542 /* To know what to release. */
543 pdeo->file = file;
544 pdeo->closing = false;
545 pdeo->c = NULL;
546 spin_lock(&pde->pde_unload_lock);
547 list_add(&pdeo->lh, &pde->pde_openers);
548 spin_unlock(&pde->pde_unload_lock);
549 } else
550 kmem_cache_free(pde_opener_cache, pdeo);
551 }
552
553 out_unuse:
554 unuse_pde(pde);
555 return rv;
556 }
557
proc_reg_release(struct inode * inode,struct file * file)558 static int proc_reg_release(struct inode *inode, struct file *file)
559 {
560 struct proc_dir_entry *pde = PDE(inode);
561 struct pde_opener *pdeo;
562
563 if (pde_is_permanent(pde)) {
564 typeof_member(struct proc_ops, proc_release) release;
565
566 release = pde->proc_ops->proc_release;
567 if (release) {
568 return release(inode, file);
569 }
570 return 0;
571 }
572
573 spin_lock(&pde->pde_unload_lock);
574 list_for_each_entry(pdeo, &pde->pde_openers, lh) {
575 if (pdeo->file == file) {
576 close_pdeo(pde, pdeo);
577 return 0;
578 }
579 }
580 spin_unlock(&pde->pde_unload_lock);
581 return 0;
582 }
583
584 static const struct file_operations proc_reg_file_ops = {
585 .llseek = proc_reg_llseek,
586 .read = proc_reg_read,
587 .write = proc_reg_write,
588 .poll = proc_reg_poll,
589 .unlocked_ioctl = proc_reg_unlocked_ioctl,
590 .mmap = proc_reg_mmap,
591 .get_unmapped_area = proc_reg_get_unmapped_area,
592 .open = proc_reg_open,
593 .release = proc_reg_release,
594 };
595
596 static const struct file_operations proc_iter_file_ops = {
597 .llseek = proc_reg_llseek,
598 .read_iter = proc_reg_read_iter,
599 .write = proc_reg_write,
600 .splice_read = generic_file_splice_read,
601 .poll = proc_reg_poll,
602 .unlocked_ioctl = proc_reg_unlocked_ioctl,
603 .mmap = proc_reg_mmap,
604 .get_unmapped_area = proc_reg_get_unmapped_area,
605 .open = proc_reg_open,
606 .release = proc_reg_release,
607 };
608
609 #ifdef CONFIG_COMPAT
610 static const struct file_operations proc_reg_file_ops_compat = {
611 .llseek = proc_reg_llseek,
612 .read = proc_reg_read,
613 .write = proc_reg_write,
614 .poll = proc_reg_poll,
615 .unlocked_ioctl = proc_reg_unlocked_ioctl,
616 .compat_ioctl = proc_reg_compat_ioctl,
617 .mmap = proc_reg_mmap,
618 .get_unmapped_area = proc_reg_get_unmapped_area,
619 .open = proc_reg_open,
620 .release = proc_reg_release,
621 };
622
623 static const struct file_operations proc_iter_file_ops_compat = {
624 .llseek = proc_reg_llseek,
625 .read_iter = proc_reg_read_iter,
626 .splice_read = generic_file_splice_read,
627 .write = proc_reg_write,
628 .poll = proc_reg_poll,
629 .unlocked_ioctl = proc_reg_unlocked_ioctl,
630 .compat_ioctl = proc_reg_compat_ioctl,
631 .mmap = proc_reg_mmap,
632 .get_unmapped_area = proc_reg_get_unmapped_area,
633 .open = proc_reg_open,
634 .release = proc_reg_release,
635 };
636 #endif
637
proc_put_link(void * p)638 static void proc_put_link(void *p)
639 {
640 unuse_pde(p);
641 }
642
proc_get_link(struct dentry * dentry,struct inode * inode,struct delayed_call * done)643 static const char *proc_get_link(struct dentry *dentry,
644 struct inode *inode,
645 struct delayed_call *done)
646 {
647 struct proc_dir_entry *pde = PDE(inode);
648 if (!use_pde(pde))
649 return ERR_PTR(-EINVAL);
650 set_delayed_call(done, proc_put_link, pde);
651 return pde->data;
652 }
653
654 const struct inode_operations proc_link_inode_operations = {
655 .get_link = proc_get_link,
656 };
657
proc_get_inode(struct super_block * sb,struct proc_dir_entry * de)658 struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
659 {
660 struct inode *inode = new_inode(sb);
661
662 if (!inode) {
663 pde_put(de);
664 return NULL;
665 }
666
667 inode->i_ino = de->low_ino;
668 inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
669 PROC_I(inode)->pde = de;
670 if (is_empty_pde(de)) {
671 make_empty_dir_inode(inode);
672 return inode;
673 }
674
675 if (de->mode) {
676 inode->i_mode = de->mode;
677 inode->i_uid = de->uid;
678 inode->i_gid = de->gid;
679 }
680 if (de->size)
681 inode->i_size = de->size;
682 if (de->nlink)
683 set_nlink(inode, de->nlink);
684
685 if (S_ISREG(inode->i_mode)) {
686 inode->i_op = de->proc_iops;
687 if (de->proc_ops->proc_read_iter)
688 inode->i_fop = &proc_iter_file_ops;
689 else
690 inode->i_fop = &proc_reg_file_ops;
691 #ifdef CONFIG_COMPAT
692 if (de->proc_ops->proc_compat_ioctl) {
693 if (de->proc_ops->proc_read_iter)
694 inode->i_fop = &proc_iter_file_ops_compat;
695 else
696 inode->i_fop = &proc_reg_file_ops_compat;
697 }
698 #endif
699 } else if (S_ISDIR(inode->i_mode)) {
700 inode->i_op = de->proc_iops;
701 inode->i_fop = de->proc_dir_ops;
702 } else if (S_ISLNK(inode->i_mode)) {
703 inode->i_op = de->proc_iops;
704 inode->i_fop = NULL;
705 } else {
706 BUG();
707 }
708 return inode;
709 }
710