xref: /openbmc/linux/fs/proc/inode.c (revision 86e281fc) 
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 inode *inode;
114 	struct proc_inode *ei;
115 	struct hlist_node *node;
116 	struct super_block *old_sb = NULL;
117 
118 	rcu_read_lock();
119 	for (;;) {
120 		struct super_block *sb;
121 		node = hlist_first_rcu(inodes);
122 		if (!node)
123 			break;
124 		ei = hlist_entry(node, struct proc_inode, sibling_inodes);
125 		spin_lock(lock);
126 		hlist_del_init_rcu(&ei->sibling_inodes);
127 		spin_unlock(lock);
128 
129 		inode = &ei->vfs_inode;
130 		sb = inode->i_sb;
131 		if ((sb != old_sb) && !atomic_inc_not_zero(&sb->s_active))
132 			continue;
133 		inode = igrab(inode);
134 		rcu_read_unlock();
135 		if (sb != old_sb) {
136 			if (old_sb)
137 				deactivate_super(old_sb);
138 			old_sb = sb;
139 		}
140 		if (unlikely(!inode)) {
141 			rcu_read_lock();
142 			continue;
143 		}
144 
145 		if (S_ISDIR(inode->i_mode)) {
146 			struct dentry *dir = d_find_any_alias(inode);
147 			if (dir) {
148 				d_invalidate(dir);
149 				dput(dir);
150 			}
151 		} else {
152 			struct dentry *dentry;
153 			while ((dentry = d_find_alias(inode))) {
154 				d_invalidate(dentry);
155 				dput(dentry);
156 			}
157 		}
158 		iput(inode);
159 
160 		rcu_read_lock();
161 	}
162 	rcu_read_unlock();
163 	if (old_sb)
164 		deactivate_super(old_sb);
165 }
166 
167 static inline const char *hidepid2str(enum proc_hidepid v)
168 {
169 	switch (v) {
170 		case HIDEPID_OFF: return "off";
171 		case HIDEPID_NO_ACCESS: return "noaccess";
172 		case HIDEPID_INVISIBLE: return "invisible";
173 		case HIDEPID_NOT_PTRACEABLE: return "ptraceable";
174 	}
175 	WARN_ONCE(1, "bad hide_pid value: %d\n", v);
176 	return "unknown";
177 }
178 
179 static int proc_show_options(struct seq_file *seq, struct dentry *root)
180 {
181 	struct proc_fs_info *fs_info = proc_sb_info(root->d_sb);
182 
183 	if (!gid_eq(fs_info->pid_gid, GLOBAL_ROOT_GID))
184 		seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, fs_info->pid_gid));
185 	if (fs_info->hide_pid != HIDEPID_OFF)
186 		seq_printf(seq, ",hidepid=%s", hidepid2str(fs_info->hide_pid));
187 	if (fs_info->pidonly != PROC_PIDONLY_OFF)
188 		seq_printf(seq, ",subset=pid");
189 
190 	return 0;
191 }
192 
193 const struct super_operations proc_sops = {
194 	.alloc_inode	= proc_alloc_inode,
195 	.free_inode	= proc_free_inode,
196 	.drop_inode	= generic_delete_inode,
197 	.evict_inode	= proc_evict_inode,
198 	.statfs		= simple_statfs,
199 	.show_options	= proc_show_options,
200 };
201 
202 enum {BIAS = -1U<<31};
203 
204 static inline int use_pde(struct proc_dir_entry *pde)
205 {
206 	return likely(atomic_inc_unless_negative(&pde->in_use));
207 }
208 
209 static void unuse_pde(struct proc_dir_entry *pde)
210 {
211 	if (unlikely(atomic_dec_return(&pde->in_use) == BIAS))
212 		complete(pde->pde_unload_completion);
213 }
214 
215 /*
216  * At most 2 contexts can enter this function: the one doing the last
217  * close on the descriptor and whoever is deleting PDE itself.
218  *
219  * First to enter calls ->proc_release hook and signals its completion
220  * to the second one which waits and then does nothing.
221  *
222  * PDE is locked on entry, unlocked on exit.
223  */
224 static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)
225 	__releases(&pde->pde_unload_lock)
226 {
227 	/*
228 	 * close() (proc_reg_release()) can't delete an entry and proceed:
229 	 * ->release hook needs to be available at the right moment.
230 	 *
231 	 * rmmod (remove_proc_entry() et al) can't delete an entry and proceed:
232 	 * "struct file" needs to be available at the right moment.
233 	 */
234 	if (pdeo->closing) {
235 		/* somebody else is doing that, just wait */
236 		DECLARE_COMPLETION_ONSTACK(c);
237 		pdeo->c = &c;
238 		spin_unlock(&pde->pde_unload_lock);
239 		wait_for_completion(&c);
240 	} else {
241 		struct file *file;
242 		struct completion *c;
243 
244 		pdeo->closing = true;
245 		spin_unlock(&pde->pde_unload_lock);
246 
247 		file = pdeo->file;
248 		pde->proc_ops->proc_release(file_inode(file), file);
249 
250 		spin_lock(&pde->pde_unload_lock);
251 		/* Strictly after ->proc_release, see above. */
252 		list_del(&pdeo->lh);
253 		c = pdeo->c;
254 		spin_unlock(&pde->pde_unload_lock);
255 		if (unlikely(c))
256 			complete(c);
257 		kmem_cache_free(pde_opener_cache, pdeo);
258 	}
259 }
260 
261 void proc_entry_rundown(struct proc_dir_entry *de)
262 {
263 	DECLARE_COMPLETION_ONSTACK(c);
264 	/* Wait until all existing callers into module are done. */
265 	de->pde_unload_completion = &c;
266 	if (atomic_add_return(BIAS, &de->in_use) != BIAS)
267 		wait_for_completion(&c);
268 
269 	/* ->pde_openers list can't grow from now on. */
270 
271 	spin_lock(&de->pde_unload_lock);
272 	while (!list_empty(&de->pde_openers)) {
273 		struct pde_opener *pdeo;
274 		pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
275 		close_pdeo(de, pdeo);
276 		spin_lock(&de->pde_unload_lock);
277 	}
278 	spin_unlock(&de->pde_unload_lock);
279 }
280 
281 static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence)
282 {
283 	struct proc_dir_entry *pde = PDE(file_inode(file));
284 	loff_t rv = -EINVAL;
285 
286 	if (pde_is_permanent(pde)) {
287 		return pde->proc_ops->proc_lseek(file, offset, whence);
288 	} else if (use_pde(pde)) {
289 		rv = pde->proc_ops->proc_lseek(file, offset, whence);
290 		unuse_pde(pde);
291 	}
292 	return rv;
293 }
294 
295 static ssize_t proc_reg_read_iter(struct kiocb *iocb, struct iov_iter *iter)
296 {
297 	struct proc_dir_entry *pde = PDE(file_inode(iocb->ki_filp));
298 	ssize_t ret;
299 
300 	if (pde_is_permanent(pde))
301 		return pde->proc_ops->proc_read_iter(iocb, iter);
302 
303 	if (!use_pde(pde))
304 		return -EIO;
305 	ret = pde->proc_ops->proc_read_iter(iocb, iter);
306 	unuse_pde(pde);
307 	return ret;
308 }
309 
310 static ssize_t pde_read(struct proc_dir_entry *pde, struct file *file, char __user *buf, size_t count, loff_t *ppos)
311 {
312 	typeof_member(struct proc_ops, proc_read) read;
313 
314 	read = pde->proc_ops->proc_read;
315 	if (read)
316 		return read(file, buf, count, ppos);
317 	return -EIO;
318 }
319 
320 static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
321 {
322 	struct proc_dir_entry *pde = PDE(file_inode(file));
323 	ssize_t rv = -EIO;
324 
325 	if (pde_is_permanent(pde)) {
326 		return pde_read(pde, file, buf, count, ppos);
327 	} else if (use_pde(pde)) {
328 		rv = pde_read(pde, file, buf, count, ppos);
329 		unuse_pde(pde);
330 	}
331 	return rv;
332 }
333 
334 static ssize_t pde_write(struct proc_dir_entry *pde, struct file *file, const char __user *buf, size_t count, loff_t *ppos)
335 {
336 	typeof_member(struct proc_ops, proc_write) write;
337 
338 	write = pde->proc_ops->proc_write;
339 	if (write)
340 		return write(file, buf, count, ppos);
341 	return -EIO;
342 }
343 
344 static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
345 {
346 	struct proc_dir_entry *pde = PDE(file_inode(file));
347 	ssize_t rv = -EIO;
348 
349 	if (pde_is_permanent(pde)) {
350 		return pde_write(pde, file, buf, count, ppos);
351 	} else if (use_pde(pde)) {
352 		rv = pde_write(pde, file, buf, count, ppos);
353 		unuse_pde(pde);
354 	}
355 	return rv;
356 }
357 
358 static __poll_t pde_poll(struct proc_dir_entry *pde, struct file *file, struct poll_table_struct *pts)
359 {
360 	typeof_member(struct proc_ops, proc_poll) poll;
361 
362 	poll = pde->proc_ops->proc_poll;
363 	if (poll)
364 		return poll(file, pts);
365 	return DEFAULT_POLLMASK;
366 }
367 
368 static __poll_t proc_reg_poll(struct file *file, struct poll_table_struct *pts)
369 {
370 	struct proc_dir_entry *pde = PDE(file_inode(file));
371 	__poll_t rv = DEFAULT_POLLMASK;
372 
373 	if (pde_is_permanent(pde)) {
374 		return pde_poll(pde, file, pts);
375 	} else if (use_pde(pde)) {
376 		rv = pde_poll(pde, file, pts);
377 		unuse_pde(pde);
378 	}
379 	return rv;
380 }
381 
382 static long pde_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
383 {
384 	typeof_member(struct proc_ops, proc_ioctl) ioctl;
385 
386 	ioctl = pde->proc_ops->proc_ioctl;
387 	if (ioctl)
388 		return ioctl(file, cmd, arg);
389 	return -ENOTTY;
390 }
391 
392 static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
393 {
394 	struct proc_dir_entry *pde = PDE(file_inode(file));
395 	long rv = -ENOTTY;
396 
397 	if (pde_is_permanent(pde)) {
398 		return pde_ioctl(pde, file, cmd, arg);
399 	} else if (use_pde(pde)) {
400 		rv = pde_ioctl(pde, file, cmd, arg);
401 		unuse_pde(pde);
402 	}
403 	return rv;
404 }
405 
406 #ifdef CONFIG_COMPAT
407 static long pde_compat_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg)
408 {
409 	typeof_member(struct proc_ops, proc_compat_ioctl) compat_ioctl;
410 
411 	compat_ioctl = pde->proc_ops->proc_compat_ioctl;
412 	if (compat_ioctl)
413 		return compat_ioctl(file, cmd, arg);
414 	return -ENOTTY;
415 }
416 
417 static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
418 {
419 	struct proc_dir_entry *pde = PDE(file_inode(file));
420 	long rv = -ENOTTY;
421 	if (pde_is_permanent(pde)) {
422 		return pde_compat_ioctl(pde, file, cmd, arg);
423 	} else if (use_pde(pde)) {
424 		rv = pde_compat_ioctl(pde, file, cmd, arg);
425 		unuse_pde(pde);
426 	}
427 	return rv;
428 }
429 #endif
430 
431 static int pde_mmap(struct proc_dir_entry *pde, struct file *file, struct vm_area_struct *vma)
432 {
433 	typeof_member(struct proc_ops, proc_mmap) mmap;
434 
435 	mmap = pde->proc_ops->proc_mmap;
436 	if (mmap)
437 		return mmap(file, vma);
438 	return -EIO;
439 }
440 
441 static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma)
442 {
443 	struct proc_dir_entry *pde = PDE(file_inode(file));
444 	int rv = -EIO;
445 
446 	if (pde_is_permanent(pde)) {
447 		return pde_mmap(pde, file, vma);
448 	} else if (use_pde(pde)) {
449 		rv = pde_mmap(pde, file, vma);
450 		unuse_pde(pde);
451 	}
452 	return rv;
453 }
454 
455 static unsigned long
456 pde_get_unmapped_area(struct proc_dir_entry *pde, struct file *file, unsigned long orig_addr,
457 			   unsigned long len, unsigned long pgoff,
458 			   unsigned long flags)
459 {
460 	typeof_member(struct proc_ops, proc_get_unmapped_area) get_area;
461 
462 	get_area = pde->proc_ops->proc_get_unmapped_area;
463 #ifdef CONFIG_MMU
464 	if (!get_area)
465 		get_area = current->mm->get_unmapped_area;
466 #endif
467 	if (get_area)
468 		return get_area(file, orig_addr, len, pgoff, flags);
469 	return orig_addr;
470 }
471 
472 static unsigned long
473 proc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,
474 			   unsigned long len, unsigned long pgoff,
475 			   unsigned long flags)
476 {
477 	struct proc_dir_entry *pde = PDE(file_inode(file));
478 	unsigned long rv = -EIO;
479 
480 	if (pde_is_permanent(pde)) {
481 		return pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);
482 	} else if (use_pde(pde)) {
483 		rv = pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);
484 		unuse_pde(pde);
485 	}
486 	return rv;
487 }
488 
489 static int proc_reg_open(struct inode *inode, struct file *file)
490 {
491 	struct proc_dir_entry *pde = PDE(inode);
492 	int rv = 0;
493 	typeof_member(struct proc_ops, proc_open) open;
494 	typeof_member(struct proc_ops, proc_release) release;
495 	struct pde_opener *pdeo;
496 
497 	if (!pde->proc_ops->proc_lseek)
498 		file->f_mode &= ~FMODE_LSEEK;
499 
500 	if (pde_is_permanent(pde)) {
501 		open = pde->proc_ops->proc_open;
502 		if (open)
503 			rv = open(inode, file);
504 		return rv;
505 	}
506 
507 	/*
508 	 * Ensure that
509 	 * 1) PDE's ->release hook will be called no matter what
510 	 *    either normally by close()/->release, or forcefully by
511 	 *    rmmod/remove_proc_entry.
512 	 *
513 	 * 2) rmmod isn't blocked by opening file in /proc and sitting on
514 	 *    the descriptor (including "rmmod foo </proc/foo" scenario).
515 	 *
516 	 * Save every "struct file" with custom ->release hook.
517 	 */
518 	if (!use_pde(pde))
519 		return -ENOENT;
520 
521 	release = pde->proc_ops->proc_release;
522 	if (release) {
523 		pdeo = kmem_cache_alloc(pde_opener_cache, GFP_KERNEL);
524 		if (!pdeo) {
525 			rv = -ENOMEM;
526 			goto out_unuse;
527 		}
528 	}
529 
530 	open = pde->proc_ops->proc_open;
531 	if (open)
532 		rv = open(inode, file);
533 
534 	if (release) {
535 		if (rv == 0) {
536 			/* To know what to release. */
537 			pdeo->file = file;
538 			pdeo->closing = false;
539 			pdeo->c = NULL;
540 			spin_lock(&pde->pde_unload_lock);
541 			list_add(&pdeo->lh, &pde->pde_openers);
542 			spin_unlock(&pde->pde_unload_lock);
543 		} else
544 			kmem_cache_free(pde_opener_cache, pdeo);
545 	}
546 
547 out_unuse:
548 	unuse_pde(pde);
549 	return rv;
550 }
551 
552 static int proc_reg_release(struct inode *inode, struct file *file)
553 {
554 	struct proc_dir_entry *pde = PDE(inode);
555 	struct pde_opener *pdeo;
556 
557 	if (pde_is_permanent(pde)) {
558 		typeof_member(struct proc_ops, proc_release) release;
559 
560 		release = pde->proc_ops->proc_release;
561 		if (release) {
562 			return release(inode, file);
563 		}
564 		return 0;
565 	}
566 
567 	spin_lock(&pde->pde_unload_lock);
568 	list_for_each_entry(pdeo, &pde->pde_openers, lh) {
569 		if (pdeo->file == file) {
570 			close_pdeo(pde, pdeo);
571 			return 0;
572 		}
573 	}
574 	spin_unlock(&pde->pde_unload_lock);
575 	return 0;
576 }
577 
578 static const struct file_operations proc_reg_file_ops = {
579 	.llseek		= proc_reg_llseek,
580 	.read		= proc_reg_read,
581 	.write		= proc_reg_write,
582 	.poll		= proc_reg_poll,
583 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
584 	.mmap		= proc_reg_mmap,
585 	.get_unmapped_area = proc_reg_get_unmapped_area,
586 	.open		= proc_reg_open,
587 	.release	= proc_reg_release,
588 };
589 
590 static const struct file_operations proc_iter_file_ops = {
591 	.llseek		= proc_reg_llseek,
592 	.read_iter	= proc_reg_read_iter,
593 	.write		= proc_reg_write,
594 	.splice_read	= copy_splice_read,
595 	.poll		= proc_reg_poll,
596 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
597 	.mmap		= proc_reg_mmap,
598 	.get_unmapped_area = proc_reg_get_unmapped_area,
599 	.open		= proc_reg_open,
600 	.release	= proc_reg_release,
601 };
602 
603 #ifdef CONFIG_COMPAT
604 static const struct file_operations proc_reg_file_ops_compat = {
605 	.llseek		= proc_reg_llseek,
606 	.read		= proc_reg_read,
607 	.write		= proc_reg_write,
608 	.poll		= proc_reg_poll,
609 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
610 	.compat_ioctl	= proc_reg_compat_ioctl,
611 	.mmap		= proc_reg_mmap,
612 	.get_unmapped_area = proc_reg_get_unmapped_area,
613 	.open		= proc_reg_open,
614 	.release	= proc_reg_release,
615 };
616 
617 static const struct file_operations proc_iter_file_ops_compat = {
618 	.llseek		= proc_reg_llseek,
619 	.read_iter	= proc_reg_read_iter,
620 	.splice_read	= copy_splice_read,
621 	.write		= proc_reg_write,
622 	.poll		= proc_reg_poll,
623 	.unlocked_ioctl	= proc_reg_unlocked_ioctl,
624 	.compat_ioctl	= proc_reg_compat_ioctl,
625 	.mmap		= proc_reg_mmap,
626 	.get_unmapped_area = proc_reg_get_unmapped_area,
627 	.open		= proc_reg_open,
628 	.release	= proc_reg_release,
629 };
630 #endif
631 
632 static void proc_put_link(void *p)
633 {
634 	unuse_pde(p);
635 }
636 
637 static const char *proc_get_link(struct dentry *dentry,
638 				 struct inode *inode,
639 				 struct delayed_call *done)
640 {
641 	struct proc_dir_entry *pde = PDE(inode);
642 	if (!use_pde(pde))
643 		return ERR_PTR(-EINVAL);
644 	set_delayed_call(done, proc_put_link, pde);
645 	return pde->data;
646 }
647 
648 const struct inode_operations proc_link_inode_operations = {
649 	.get_link	= proc_get_link,
650 };
651 
652 struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)
653 {
654 	struct inode *inode = new_inode(sb);
655 
656 	if (!inode) {
657 		pde_put(de);
658 		return NULL;
659 	}
660 
661 	inode->i_private = de->data;
662 	inode->i_ino = de->low_ino;
663 	inode->i_mtime = inode->i_atime = inode_set_ctime_current(inode);
664 	PROC_I(inode)->pde = de;
665 	if (is_empty_pde(de)) {
666 		make_empty_dir_inode(inode);
667 		return inode;
668 	}
669 
670 	if (de->mode) {
671 		inode->i_mode = de->mode;
672 		inode->i_uid = de->uid;
673 		inode->i_gid = de->gid;
674 	}
675 	if (de->size)
676 		inode->i_size = de->size;
677 	if (de->nlink)
678 		set_nlink(inode, de->nlink);
679 
680 	if (S_ISREG(inode->i_mode)) {
681 		inode->i_op = de->proc_iops;
682 		if (de->proc_ops->proc_read_iter)
683 			inode->i_fop = &proc_iter_file_ops;
684 		else
685 			inode->i_fop = &proc_reg_file_ops;
686 #ifdef CONFIG_COMPAT
687 		if (de->proc_ops->proc_compat_ioctl) {
688 			if (de->proc_ops->proc_read_iter)
689 				inode->i_fop = &proc_iter_file_ops_compat;
690 			else
691 				inode->i_fop = &proc_reg_file_ops_compat;
692 		}
693 #endif
694 	} else if (S_ISDIR(inode->i_mode)) {
695 		inode->i_op = de->proc_iops;
696 		inode->i_fop = de->proc_dir_ops;
697 	} else if (S_ISLNK(inode->i_mode)) {
698 		inode->i_op = de->proc_iops;
699 		inode->i_fop = NULL;
700 	} else {
701 		BUG();
702 	}
703 	return inode;
704 }
705