xref: /linux/fs/proc/inode.c (revision f6154d8babbb8a98f0d3ea325aafae2e33bfd8be) 
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 "internal.h"
30 
31 static void proc_evict_inode(struct inode *inode)
32 {
33 	struct proc_dir_entry *de;
34 	struct ctl_table_header *head;
35 	struct proc_inode *ei = PROC_I(inode);
36 
37 	truncate_inode_pages_final(&inode->i_data);
38 	clear_inode(inode);
39 
40 	/* Stop tracking associated processes */
41 	if (ei->pid) {
42 		proc_pid_evict_inode(ei);
43 		ei->pid = NULL;
44 	}
45 
46 	/* Let go of any associated proc directory entry */
47 	de = ei->pde;
48 	if (de) {
49 		pde_put(de);
50 		ei->pde = NULL;
51 	}
52 
53 	head = ei->sysctl;
54 	if (head) {
55 		RCU_INIT_POINTER(ei->sysctl, NULL);
56 		proc_sys_evict_inode(inode, head);
57 	}
58 }
59 
60 static struct kmem_cache *proc_inode_cachep __ro_after_init;
61 static struct kmem_cache *pde_opener_cache __ro_after_init;
62 
63 static struct inode *proc_alloc_inode(struct super_block *sb)
64 {
65 	struct proc_inode *ei;
66 
67 	ei = alloc_inode_sb(sb, proc_inode_cachep, GFP_KERNEL);
68 	if (!ei)
69 		return NULL;
70 	ei->pid = NULL;
71 	ei->fd = 0;
72 	ei->op.proc_get_link = NULL;
73 	ei->pde = NULL;
74 	ei->sysctl = NULL;
75 	ei->sysctl_entry = NULL;
76 	INIT_HLIST_NODE(&ei->sibling_inodes);
77 	ei->ns_ops = NULL;
78 	return &ei->vfs_inode;
79 }
80 
81 static void proc_free_inode(struct inode *inode)
82 {
83 	kmem_cache_free(proc_inode_cachep, PROC_I(inode));
84 }
85 
86 static void init_once(void *foo)
87 {
88 	struct proc_inode *ei = (struct proc_inode *) foo;
89 
90 	inode_init_once(&ei->vfs_inode);
91 }
92 
93 void __init proc_init_kmemcache(void)
94 {
95 	proc_inode_cachep = kmem_cache_create("proc_inode_cache",
96 					     sizeof(struct proc_inode),
97 					     0, (SLAB_RECLAIM_ACCOUNT|
98 						SLAB_MEM_SPREAD|SLAB_ACCOUNT|
99 						SLAB_PANIC),
100 					     init_once);
101 	pde_opener_cache =
102 		kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,
103 				  SLAB_ACCOUNT|SLAB_PANIC, NULL);
104 	proc_dir_entry_cache = kmem_cache_create_usercopy(
105 		"proc_dir_entry", SIZEOF_PDE, 0, SLAB_PANIC,
106 		offsetof(struct proc_dir_entry, inline_name),
107 		SIZEOF_PDE_INLINE_NAME, NULL);
108 	BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);
109 }
110 
111 void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock)
112 {
113 	struct hlist_node *node;
114 	struct super_block *old_sb = NULL;
115 
116 	rcu_read_lock();
117 	while ((node = hlist_first_rcu(inodes))) {
118 		struct proc_inode *ei = hlist_entry(node, struct proc_inode, sibling_inodes);
119 		struct super_block *sb;
120 		struct inode *inode;
121 
122 		spin_lock(lock);
123 		hlist_del_init_rcu(&ei->sibling_inodes);
124 		spin_unlock(lock);
125 
126 		inode = &ei->vfs_inode;
127 		sb = inode->i_sb;
128 		if ((sb != old_sb) && !atomic_inc_not_zero(&sb->s_active))
129 			continue;
130 		inode = igrab(inode);
131 		rcu_read_unlock();
132 		if (sb != old_sb) {
133 			if (old_sb)
134 				deactivate_super(old_sb);
135 			old_sb = sb;
136 		}
137 		if (unlikely(!inode)) {
138 			rcu_read_lock();
139 			continue;
140 		}
141 
142 		if (S_ISDIR(inode->i_mode)) {
143 			struct dentry *dir = d_find_any_alias(inode);
144 			if (dir) {
145 				d_invalidate(dir);
146 				dput(dir);
147 			}
148 		} else {
149 			struct dentry *dentry;
150 			while ((dentry = d_find_alias(inode))) {
151 				d_invalidate(dentry);
152 				dput(dentry);
153 			}
154 		}
155 		iput(inode);
156 
157 		rcu_read_lock();
158 	}
159 	rcu_read_unlock();
160 	if (old_sb)
161 		deactivate_super(old_sb);
162 }
163 
164 static inline const char *hidepid2str(enum proc_hidepid v)
165 {
166 	switch (v) {
167 		case HIDEPID_OFF: return "off";
168 		case HIDEPID_NO_ACCESS: return "noaccess";
169 		case HIDEPID_INVISIBLE: return "invisible";
170 		case HIDEPID_NOT_PTRACEABLE: return "ptraceable";
171 	}
172 	WARN_ONCE(1, "bad hide_pid value: %d\n", v);
173 	return "unknown";
174 }
175 
176 static int proc_show_options(struct seq_file *seq, struct dentry *root)
177 {
178 	struct proc_fs_info *fs_info = proc_sb_info(root->d_sb);
179 
180 	if (!gid_eq(fs_info->pid_gid, GLOBAL_ROOT_GID))
181 		seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, fs_info->pid_gid));
182 	if (fs_info->hide_pid != HIDEPID_OFF)
183 		seq_printf(seq, ",hidepid=%s", hidepid2str(fs_info->hide_pid));
184 	if (fs_info->pidonly != PROC_PIDONLY_OFF)
185 		seq_printf(seq, ",subset=pid");
186 
187 	return 0;
188 }
189 
190 const struct super_operations proc_sops = {
191 	.alloc_inode	= proc_alloc_inode,
192 	.free_inode	= proc_free_inode,
193 	.drop_inode	= generic_delete_inode,
194 	.evict_inode	= proc_evict_inode,
195 	.statfs		= simple_statfs,
196 	.show_options	= proc_show_options,
197 };
198 
199 enum {BIAS = -1U<<31};
200 
201 static inline int use_pde(struct proc_dir_entry *pde)
202 {
203 	return likely(atomic_inc_unless_negative(&pde->in_use));
204 }
205 
206 static void unuse_pde(struct proc_dir_entry *pde)
207 {
208 	if (unlikely(atomic_dec_return(&pde->in_use) == BIAS))
209 		complete(pde->pde_unload_completion);
210 }
211 
212 /*
213  * At most 2 contexts can enter this function: the one doing the last
214  * close on the descriptor and whoever is deleting PDE itself.
215  *
216  * First to enter calls ->proc_release hook and signals its completion
217  * to the second one which waits and then does nothing.
218  *
219  * PDE is locked on entry, unlocked on exit.
220  */
221 static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
222 	__releases(&pde->pde_unload_lock)
223 {
224 	/*
225 	 * close() (proc_reg_release()) can't delete an entry and proceed:
226 	 * ->release hook needs to be available at the right moment.
227 	 *
228 	 * rmmod (remove_proc_entry() et al) can't delete an entry and proceed:
229 	 * "struct file" needs to be available at the right moment.
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 
244 		file = pdeo->file;
245 		pde->proc_ops->proc_release(file_inode(file), file);
246 
247 		spin_lock(&pde->pde_unload_lock);
248 		/* Strictly after ->proc_release, see above. */
249 		list_del(&pdeo->lh);
250 		c = pdeo->c;
251 		spin_unlock(&pde->pde_unload_lock);
252 		if (unlikely(c))
253 			complete(c);
254 		kmem_cache_free(pde_opener_cache, pdeo);
255 	}
256 }
257 
258 void proc_entry_rundown(struct proc_dir_entry *de)
259 {
260 	DECLARE_COMPLETION_ONSTACK(c);
261 	/* Wait until all existing callers into module are done. */
262 	de->pde_unload_completion = &c;
263 	if (atomic_add_return(BIAS, &de->in_use) != BIAS)
264 		wait_for_completion(&c);
265 
266 	/* ->pde_openers list can't grow from now on. */
267 
268 	spin_lock(&de->pde_unload_lock);
269 	while (!list_empty(&de->pde_openers)) {
270 		struct pde_opener *pdeo;
271 		pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
272 		close_pdeo(de, pdeo);
273 		spin_lock(&de->pde_unload_lock);
274 	}
275 	spin_unlock(&de->pde_unload_lock);
276 }
277 
278 static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
279 {
280 	struct proc_dir_entry *pde = PDE(file_inode(file));
281 	loff_t rv = -EINVAL;
282 
283 	if (pde_is_permanent(pde)) {
284 		return pde->proc_ops->proc_lseek(file, offset, whence);
285 	} else if (use_pde(pde)) {
286 		rv = pde->proc_ops->proc_lseek(file, offset, whence);
287 		unuse_pde(pde);
288 	}
289 	return rv;
290 }
291 
292 static ssize_t proc_reg_read_iter(struct kiocb *iocb, struct iov_iter *iter)
293 {
294 	struct proc_dir_entry *pde = PDE(file_inode(iocb->ki_filp));
295 	ssize_t ret;
296 
297 	if (pde_is_permanent(pde))
298 		return pde->proc_ops->proc_read_iter(iocb, iter);
299 
300 	if (!use_pde(pde))
301 		return -EIO;
302 	ret = pde->proc_ops->proc_read_iter(iocb, iter);
303 	unuse_pde(pde);
304 	return ret;
305 }
306 
307 static ssize_t pde_read(struct proc_dir_entry *pde, struct file *file, char __user *buf, size_t count, loff_t *ppos)
308 {
309 	typeof_member(struct proc_ops, proc_read) read;
310 
311 	read = pde->proc_ops->proc_read;
312 	if (read)
313 		return read(file, buf, count, ppos);
314 	return -EIO;
315 }
316 
317 static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
318 {
319 	struct proc_dir_entry *pde = PDE(file_inode(file));
320 	ssize_t rv = -EIO;
321 
322 	if (pde_is_permanent(pde)) {
323 		return pde_read(pde, file, buf, count, ppos);
324 	} else if (use_pde(pde)) {
325 		rv = pde_read(pde, file, buf, count, ppos);
326 		unuse_pde(pde);
327 	}
328 	return rv;
329 }
330 
331 static ssize_t pde_write(struct proc_dir_entry *pde, struct file *file, const char __user *buf, size_t count, loff_t *ppos)
332 {
333 	typeof_member(struct proc_ops, proc_write) write;
334 
335 	write = pde->proc_ops->proc_write;
336 	if (write)
337 		return write(file, buf, count, ppos);
338 	return -EIO;
339 }
340 
341 static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
342 {
343 	struct proc_dir_entry *pde = PDE(file_inode(file));
344 	ssize_t rv = -EIO;
345 
346 	if (pde_is_permanent(pde)) {
347 		return pde_write(pde, file, buf, count, ppos);
348 	} else if (use_pde(pde)) {
349 		rv = pde_write(pde, file, buf, count, ppos);
350 		unuse_pde(pde);
351 	}
352 	return rv;
353 }
354 
355 static __poll_t pde_poll(struct proc_dir_entry *pde, struct file *file, struct poll_table_struct *pts)
356 {
357 	typeof_member(struct proc_ops, proc_poll) poll;
358 
359 	poll = pde->proc_ops->proc_poll;
360 	if (poll)
361 		return poll(file, pts);
362 	return DEFAULT_POLLMASK;
363 }
364 
365 static __poll_t proc_reg_poll(struct file *file, struct poll_table_struct *pts)
366 {
367 	struct proc_dir_entry *pde = PDE(file_inode(file));
368 	__poll_t rv = DEFAULT_POLLMASK;
369 
370 	if (pde_is_permanent(pde)) {
371 		return pde_poll(pde, file, pts);
372 	} else if (use_pde(pde)) {
373 		rv = pde_poll(pde, file, pts);
374 		unuse_pde(pde);
375 	}
376 	return rv;
377 }
378 
379 static long pde_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
380 {
381 	typeof_member(struct proc_ops, proc_ioctl) ioctl;
382 
383 	ioctl = pde->proc_ops->proc_ioctl;
384 	if (ioctl)
385 		return ioctl(file, cmd, arg);
386 	return -ENOTTY;
387 }
388 
389 static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
390 {
391 	struct proc_dir_entry *pde = PDE(file_inode(file));
392 	long rv = -ENOTTY;
393 
394 	if (pde_is_permanent(pde)) {
395 		return pde_ioctl(pde, file, cmd, arg);
396 	} else if (use_pde(pde)) {
397 		rv = pde_ioctl(pde, file, cmd, arg);
398 		unuse_pde(pde);
399 	}
400 	return rv;
401 }
402 
403 #ifdef CONFIG_COMPAT
404 static long pde_compat_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
405 {
406 	typeof_member(struct proc_ops, proc_compat_ioctl) compat_ioctl;
407 
408 	compat_ioctl = pde->proc_ops->proc_compat_ioctl;
409 	if (compat_ioctl)
410 		return compat_ioctl(file, cmd, arg);
411 	return -ENOTTY;
412 }
413 
414 static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
415 {
416 	struct proc_dir_entry *pde = PDE(file_inode(file));
417 	long rv = -ENOTTY;
418 	if (pde_is_permanent(pde)) {
419 		return pde_compat_ioctl(pde, file, cmd, arg);
420 	} else if (use_pde(pde)) {
421 		rv = pde_compat_ioctl(pde, file, cmd, arg);
422 		unuse_pde(pde);
423 	}
424 	return rv;
425 }
426 #endif
427 
428 static int pde_mmap(struct proc_dir_entry *pde, struct file *file, struct vm_area_struct *vma)
429 {
430 	typeof_member(struct proc_ops, proc_mmap) mmap;
431 
432 	mmap = pde->proc_ops->proc_mmap;
433 	if (mmap)
434 		return mmap(file, vma);
435 	return -EIO;
436 }
437 
438 static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
439 {
440 	struct proc_dir_entry *pde = PDE(file_inode(file));
441 	int rv = -EIO;
442 
443 	if (pde_is_permanent(pde)) {
444 		return pde_mmap(pde, file, vma);
445 	} else if (use_pde(pde)) {
446 		rv = pde_mmap(pde, file, vma);
447 		unuse_pde(pde);
448 	}
449 	return rv;
450 }
451 
452 static unsigned long
453 pde_get_unmapped_area(struct proc_dir_entry *pde, struct file *file, unsigned long orig_addr,
454 			   unsigned long len, unsigned long pgoff,
455 			   unsigned long flags)
456 {
457 	typeof_member(struct proc_ops, proc_get_unmapped_area) get_area;
458 
459 	get_area = pde->proc_ops->proc_get_unmapped_area;
460 #ifdef CONFIG_MMU
461 	if (!get_area)
462 		get_area = current->mm->get_unmapped_area;
463 #endif
464 	if (get_area)
465 		return get_area(file, orig_addr, len, pgoff, flags);
466 	return orig_addr;
467 }
468 
469 static unsigned long
470 proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
471 			   unsigned long len, unsigned long pgoff,
472 			   unsigned long flags)
473 {
474 	struct proc_dir_entry *pde = PDE(file_inode(file));
475 	unsigned long rv = -EIO;
476 
477 	if (pde_is_permanent(pde)) {
478 		return pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);
479 	} else if (use_pde(pde)) {
480 		rv = pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);
481 		unuse_pde(pde);
482 	}
483 	return rv;
484 }
485 
486 static int proc_reg_open(struct inode *inode, struct file *file)
487 {
488 	struct proc_dir_entry *pde = PDE(inode);
489 	int rv = 0;
490 	typeof_member(struct proc_ops, proc_open) open;
491 	typeof_member(struct proc_ops, proc_release) release;
492 	struct pde_opener *pdeo;
493 
494 	if (!pde->proc_ops->proc_lseek)
495 		file->f_mode &= ~FMODE_LSEEK;
496 
497 	if (pde_is_permanent(pde)) {
498 		open = pde->proc_ops->proc_open;
499 		if (open)
500 			rv = open(inode, file);
501 		return rv;
502 	}
503 
504 	/*
505 	 * Ensure that
506 	 * 1) PDE's ->release hook will be called no matter what
507 	 *    either normally by close()/->release, or forcefully by
508 	 *    rmmod/remove_proc_entry.
509 	 *
510 	 * 2) rmmod isn't blocked by opening file in /proc and sitting on
511 	 *    the descriptor (including "rmmod foo </proc/foo" scenario).
512 	 *
513 	 * Save every "struct file" with custom ->release hook.
514 	 */
515 	if (!use_pde(pde))
516 		return -ENOENT;
517 
518 	release = pde->proc_ops->proc_release;
519 	if (release) {
520 		pdeo = kmem_cache_alloc(pde_opener_cache, GFP_KERNEL);
521 		if (!pdeo) {
522 			rv = -ENOMEM;
523 			goto out_unuse;
524 		}
525 	}
526 
527 	open = pde->proc_ops->proc_open;
528 	if (open)
529 		rv = open(inode, file);
530 
531 	if (release) {
532 		if (rv == 0) {
533 			/* To know what to release. */
534 			pdeo->file = file;
535 			pdeo->closing = false;
536 			pdeo->c = NULL;
537 			spin_lock(&pde->pde_unload_lock);
538 			list_add(&pdeo->lh, &pde->pde_openers);
539 			spin_unlock(&pde->pde_unload_lock);
540 		} else
541 			kmem_cache_free(pde_opener_cache, pdeo);
542 	}
543 
544 out_unuse:
545 	unuse_pde(pde);
546 	return rv;
547 }
548 
549 static int proc_reg_release(struct inode *inode, struct file *file)
550 {
551 	struct proc_dir_entry *pde = PDE(inode);
552 	struct pde_opener *pdeo;
553 
554 	if (pde_is_permanent(pde)) {
555 		typeof_member(struct proc_ops, proc_release) release;
556 
557 		release = pde->proc_ops->proc_release;
558 		if (release) {
559 			return release(inode, file);
560 		}
561 		return 0;
562 	}
563 
564 	spin_lock(&pde->pde_unload_lock);
565 	list_for_each_entry(pdeo, &pde->pde_openers, lh) {
566 		if (pdeo->file == file) {
567 			close_pdeo(pde, pdeo);
568 			return 0;
569 		}
570 	}
571 	spin_unlock(&pde->pde_unload_lock);
572 	return 0;
573 }
574 
575 static const struct file_operations proc_reg_file_ops = {
576 	.llseek		= proc_reg_llseek,
577 	.read		= proc_reg_read,
578 	.write		= proc_reg_write,
579 	.poll		= proc_reg_poll,
580 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
581 	.mmap		= proc_reg_mmap,
582 	.get_unmapped_area = proc_reg_get_unmapped_area,
583 	.open		= proc_reg_open,
584 	.release	= proc_reg_release,
585 };
586 
587 static const struct file_operations proc_iter_file_ops = {
588 	.llseek		= proc_reg_llseek,
589 	.read_iter	= proc_reg_read_iter,
590 	.write		= proc_reg_write,
591 	.splice_read	= copy_splice_read,
592 	.poll		= proc_reg_poll,
593 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
594 	.mmap		= proc_reg_mmap,
595 	.get_unmapped_area = proc_reg_get_unmapped_area,
596 	.open		= proc_reg_open,
597 	.release	= proc_reg_release,
598 };
599 
600 #ifdef CONFIG_COMPAT
601 static const struct file_operations proc_reg_file_ops_compat = {
602 	.llseek		= proc_reg_llseek,
603 	.read		= proc_reg_read,
604 	.write		= proc_reg_write,
605 	.poll		= proc_reg_poll,
606 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
607 	.compat_ioctl	= proc_reg_compat_ioctl,
608 	.mmap		= proc_reg_mmap,
609 	.get_unmapped_area = proc_reg_get_unmapped_area,
610 	.open		= proc_reg_open,
611 	.release	= proc_reg_release,
612 };
613 
614 static const struct file_operations proc_iter_file_ops_compat = {
615 	.llseek		= proc_reg_llseek,
616 	.read_iter	= proc_reg_read_iter,
617 	.splice_read	= copy_splice_read,
618 	.write		= proc_reg_write,
619 	.poll		= proc_reg_poll,
620 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
621 	.compat_ioctl	= proc_reg_compat_ioctl,
622 	.mmap		= proc_reg_mmap,
623 	.get_unmapped_area = proc_reg_get_unmapped_area,
624 	.open		= proc_reg_open,
625 	.release	= proc_reg_release,
626 };
627 #endif
628 
629 static void proc_put_link(void *p)
630 {
631 	unuse_pde(p);
632 }
633 
634 static const char *proc_get_link(struct dentry *dentry,
635 				 struct inode *inode,
636 				 struct delayed_call *done)
637 {
638 	struct proc_dir_entry *pde = PDE(inode);
639 	if (!use_pde(pde))
640 		return ERR_PTR(-EINVAL);
641 	set_delayed_call(done, proc_put_link, pde);
642 	return pde->data;
643 }
644 
645 const struct inode_operations proc_link_inode_operations = {
646 	.get_link	= proc_get_link,
647 };
648 
649 struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
650 {
651 	struct inode *inode = new_inode(sb);
652 
653 	if (!inode) {
654 		pde_put(de);
655 		return NULL;
656 	}
657 
658 	inode->i_private = de->data;
659 	inode->i_ino = de->low_ino;
660 	simple_inode_init_ts(inode);
661 	PROC_I(inode)->pde = de;
662 	if (is_empty_pde(de)) {
663 		make_empty_dir_inode(inode);
664 		return inode;
665 	}
666 
667 	if (de->mode) {
668 		inode->i_mode = de->mode;
669 		inode->i_uid = de->uid;
670 		inode->i_gid = de->gid;
671 	}
672 	if (de->size)
673 		inode->i_size = de->size;
674 	if (de->nlink)
675 		set_nlink(inode, de->nlink);
676 
677 	if (S_ISREG(inode->i_mode)) {
678 		inode->i_op = de->proc_iops;
679 		if (de->proc_ops->proc_read_iter)
680 			inode->i_fop = &proc_iter_file_ops;
681 		else
682 			inode->i_fop = &proc_reg_file_ops;
683 #ifdef CONFIG_COMPAT
684 		if (de->proc_ops->proc_compat_ioctl) {
685 			if (de->proc_ops->proc_read_iter)
686 				inode->i_fop = &proc_iter_file_ops_compat;
687 			else
688 				inode->i_fop = &proc_reg_file_ops_compat;
689 		}
690 #endif
691 	} else if (S_ISDIR(inode->i_mode)) {
692 		inode->i_op = de->proc_iops;
693 		inode->i_fop = de->proc_dir_ops;
694 	} else if (S_ISLNK(inode->i_mode)) {
695 		inode->i_op = de->proc_iops;
696 		inode->i_fop = NULL;
697 	} else {
698 		BUG();
699 	}
700 	return inode;
701 }
702