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1 /*
2  * proc/fs/generic.c --- generic routines for the proc-fs
3  *
4  * This file contains generic proc-fs routines for handling
5  * directories and files.
6  *
7  * Copyright (C) 1991, 1992 Linus Torvalds.
8  * Copyright (C) 1997 Theodore Ts'o
9  */
10 
11 #include <linux/errno.h>
12 #include <linux/time.h>
13 #include <linux/proc_fs.h>
14 #include <linux/stat.h>
15 #include <linux/mm.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/mount.h>
19 #include <linux/init.h>
20 #include <linux/idr.h>
21 #include <linux/namei.h>
22 #include <linux/bitops.h>
23 #include <linux/spinlock.h>
24 #include <linux/completion.h>
25 #include <asm/uaccess.h>
26 
27 #include "internal.h"
28 
29 DEFINE_SPINLOCK(proc_subdir_lock);
30 
proc_match(unsigned int len,const char * name,struct proc_dir_entry * de)31 static int proc_match(unsigned int len, const char *name, struct proc_dir_entry *de)
32 {
33 	if (de->namelen != len)
34 		return 0;
35 	return !memcmp(name, de->name, len);
36 }
37 
38 /* buffer size is one page but our output routines use some slack for overruns */
39 #define PROC_BLOCK_SIZE	(PAGE_SIZE - 1024)
40 
41 static ssize_t
__proc_file_read(struct file * file,char __user * buf,size_t nbytes,loff_t * ppos)42 __proc_file_read(struct file *file, char __user *buf, size_t nbytes,
43 	       loff_t *ppos)
44 {
45 	struct inode * inode = file->f_path.dentry->d_inode;
46 	char 	*page;
47 	ssize_t	retval=0;
48 	int	eof=0;
49 	ssize_t	n, count;
50 	char	*start;
51 	struct proc_dir_entry * dp;
52 	unsigned long long pos;
53 
54 	/*
55 	 * Gaah, please just use "seq_file" instead. The legacy /proc
56 	 * interfaces cut loff_t down to off_t for reads, and ignore
57 	 * the offset entirely for writes..
58 	 */
59 	pos = *ppos;
60 	if (pos > MAX_NON_LFS)
61 		return 0;
62 	if (nbytes > MAX_NON_LFS - pos)
63 		nbytes = MAX_NON_LFS - pos;
64 
65 	dp = PDE(inode);
66 	if (!(page = (char*) __get_free_page(GFP_TEMPORARY)))
67 		return -ENOMEM;
68 
69 	while ((nbytes > 0) && !eof) {
70 		count = min_t(size_t, PROC_BLOCK_SIZE, nbytes);
71 
72 		start = NULL;
73 		if (dp->read_proc) {
74 			/*
75 			 * How to be a proc read function
76 			 * ------------------------------
77 			 * Prototype:
78 			 *    int f(char *buffer, char **start, off_t offset,
79 			 *          int count, int *peof, void *dat)
80 			 *
81 			 * Assume that the buffer is "count" bytes in size.
82 			 *
83 			 * If you know you have supplied all the data you
84 			 * have, set *peof.
85 			 *
86 			 * You have three ways to return data:
87 			 * 0) Leave *start = NULL.  (This is the default.)
88 			 *    Put the data of the requested offset at that
89 			 *    offset within the buffer.  Return the number (n)
90 			 *    of bytes there are from the beginning of the
91 			 *    buffer up to the last byte of data.  If the
92 			 *    number of supplied bytes (= n - offset) is
93 			 *    greater than zero and you didn't signal eof
94 			 *    and the reader is prepared to take more data
95 			 *    you will be called again with the requested
96 			 *    offset advanced by the number of bytes
97 			 *    absorbed.  This interface is useful for files
98 			 *    no larger than the buffer.
99 			 * 1) Set *start = an unsigned long value less than
100 			 *    the buffer address but greater than zero.
101 			 *    Put the data of the requested offset at the
102 			 *    beginning of the buffer.  Return the number of
103 			 *    bytes of data placed there.  If this number is
104 			 *    greater than zero and you didn't signal eof
105 			 *    and the reader is prepared to take more data
106 			 *    you will be called again with the requested
107 			 *    offset advanced by *start.  This interface is
108 			 *    useful when you have a large file consisting
109 			 *    of a series of blocks which you want to count
110 			 *    and return as wholes.
111 			 *    (Hack by Paul.Russell@rustcorp.com.au)
112 			 * 2) Set *start = an address within the buffer.
113 			 *    Put the data of the requested offset at *start.
114 			 *    Return the number of bytes of data placed there.
115 			 *    If this number is greater than zero and you
116 			 *    didn't signal eof and the reader is prepared to
117 			 *    take more data you will be called again with the
118 			 *    requested offset advanced by the number of bytes
119 			 *    absorbed.
120 			 */
121 			n = dp->read_proc(page, &start, *ppos,
122 					  count, &eof, dp->data);
123 		} else
124 			break;
125 
126 		if (n == 0)   /* end of file */
127 			break;
128 		if (n < 0) {  /* error */
129 			if (retval == 0)
130 				retval = n;
131 			break;
132 		}
133 
134 		if (start == NULL) {
135 			if (n > PAGE_SIZE) {
136 				printk(KERN_ERR
137 				       "proc_file_read: Apparent buffer overflow!\n");
138 				n = PAGE_SIZE;
139 			}
140 			n -= *ppos;
141 			if (n <= 0)
142 				break;
143 			if (n > count)
144 				n = count;
145 			start = page + *ppos;
146 		} else if (start < page) {
147 			if (n > PAGE_SIZE) {
148 				printk(KERN_ERR
149 				       "proc_file_read: Apparent buffer overflow!\n");
150 				n = PAGE_SIZE;
151 			}
152 			if (n > count) {
153 				/*
154 				 * Don't reduce n because doing so might
155 				 * cut off part of a data block.
156 				 */
157 				printk(KERN_WARNING
158 				       "proc_file_read: Read count exceeded\n");
159 			}
160 		} else /* start >= page */ {
161 			unsigned long startoff = (unsigned long)(start - page);
162 			if (n > (PAGE_SIZE - startoff)) {
163 				printk(KERN_ERR
164 				       "proc_file_read: Apparent buffer overflow!\n");
165 				n = PAGE_SIZE - startoff;
166 			}
167 			if (n > count)
168 				n = count;
169 		}
170 
171  		n -= copy_to_user(buf, start < page ? page : start, n);
172 		if (n == 0) {
173 			if (retval == 0)
174 				retval = -EFAULT;
175 			break;
176 		}
177 
178 		*ppos += start < page ? (unsigned long)start : n;
179 		nbytes -= n;
180 		buf += n;
181 		retval += n;
182 	}
183 	free_page((unsigned long) page);
184 	return retval;
185 }
186 
187 static ssize_t
proc_file_read(struct file * file,char __user * buf,size_t nbytes,loff_t * ppos)188 proc_file_read(struct file *file, char __user *buf, size_t nbytes,
189 	       loff_t *ppos)
190 {
191 	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
192 	ssize_t rv = -EIO;
193 
194 	spin_lock(&pde->pde_unload_lock);
195 	if (!pde->proc_fops) {
196 		spin_unlock(&pde->pde_unload_lock);
197 		return rv;
198 	}
199 	pde->pde_users++;
200 	spin_unlock(&pde->pde_unload_lock);
201 
202 	rv = __proc_file_read(file, buf, nbytes, ppos);
203 
204 	pde_users_dec(pde);
205 	return rv;
206 }
207 
208 static ssize_t
proc_file_write(struct file * file,const char __user * buffer,size_t count,loff_t * ppos)209 proc_file_write(struct file *file, const char __user *buffer,
210 		size_t count, loff_t *ppos)
211 {
212 	struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
213 	ssize_t rv = -EIO;
214 
215 	if (pde->write_proc) {
216 		spin_lock(&pde->pde_unload_lock);
217 		if (!pde->proc_fops) {
218 			spin_unlock(&pde->pde_unload_lock);
219 			return rv;
220 		}
221 		pde->pde_users++;
222 		spin_unlock(&pde->pde_unload_lock);
223 
224 		/* FIXME: does this routine need ppos?  probably... */
225 		rv = pde->write_proc(file, buffer, count, pde->data);
226 		pde_users_dec(pde);
227 	}
228 	return rv;
229 }
230 
231 
232 static loff_t
proc_file_lseek(struct file * file,loff_t offset,int orig)233 proc_file_lseek(struct file *file, loff_t offset, int orig)
234 {
235 	loff_t retval = -EINVAL;
236 	switch (orig) {
237 	case 1:
238 		offset += file->f_pos;
239 	/* fallthrough */
240 	case 0:
241 		if (offset < 0 || offset > MAX_NON_LFS)
242 			break;
243 		file->f_pos = retval = offset;
244 	}
245 	return retval;
246 }
247 
248 static const struct file_operations proc_file_operations = {
249 	.llseek		= proc_file_lseek,
250 	.read		= proc_file_read,
251 	.write		= proc_file_write,
252 };
253 
proc_notify_change(struct dentry * dentry,struct iattr * iattr)254 static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
255 {
256 	struct inode *inode = dentry->d_inode;
257 	struct proc_dir_entry *de = PDE(inode);
258 	int error;
259 
260 	error = inode_change_ok(inode, iattr);
261 	if (error)
262 		return error;
263 
264 	if ((iattr->ia_valid & ATTR_SIZE) &&
265 	    iattr->ia_size != i_size_read(inode)) {
266 		error = vmtruncate(inode, iattr->ia_size);
267 		if (error)
268 			return error;
269 	}
270 
271 	setattr_copy(inode, iattr);
272 	mark_inode_dirty(inode);
273 
274 	de->uid = inode->i_uid;
275 	de->gid = inode->i_gid;
276 	de->mode = inode->i_mode;
277 	return 0;
278 }
279 
proc_getattr(struct vfsmount * mnt,struct dentry * dentry,struct kstat * stat)280 static int proc_getattr(struct vfsmount *mnt, struct dentry *dentry,
281 			struct kstat *stat)
282 {
283 	struct inode *inode = dentry->d_inode;
284 	struct proc_dir_entry *de = PROC_I(inode)->pde;
285 	if (de && de->nlink)
286 		set_nlink(inode, de->nlink);
287 
288 	generic_fillattr(inode, stat);
289 	return 0;
290 }
291 
292 static const struct inode_operations proc_file_inode_operations = {
293 	.setattr	= proc_notify_change,
294 };
295 
296 /*
297  * This function parses a name such as "tty/driver/serial", and
298  * returns the struct proc_dir_entry for "/proc/tty/driver", and
299  * returns "serial" in residual.
300  */
__xlate_proc_name(const char * name,struct proc_dir_entry ** ret,const char ** residual)301 static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
302 			     const char **residual)
303 {
304 	const char     		*cp = name, *next;
305 	struct proc_dir_entry	*de;
306 	unsigned int		len;
307 
308 	de = *ret;
309 	if (!de)
310 		de = &proc_root;
311 
312 	while (1) {
313 		next = strchr(cp, '/');
314 		if (!next)
315 			break;
316 
317 		len = next - cp;
318 		for (de = de->subdir; de ; de = de->next) {
319 			if (proc_match(len, cp, de))
320 				break;
321 		}
322 		if (!de) {
323 			WARN(1, "name '%s'\n", name);
324 			return -ENOENT;
325 		}
326 		cp += len + 1;
327 	}
328 	*residual = cp;
329 	*ret = de;
330 	return 0;
331 }
332 
xlate_proc_name(const char * name,struct proc_dir_entry ** ret,const char ** residual)333 static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
334 			   const char **residual)
335 {
336 	int rv;
337 
338 	spin_lock(&proc_subdir_lock);
339 	rv = __xlate_proc_name(name, ret, residual);
340 	spin_unlock(&proc_subdir_lock);
341 	return rv;
342 }
343 
344 static DEFINE_IDA(proc_inum_ida);
345 static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */
346 
347 #define PROC_DYNAMIC_FIRST 0xF0000000U
348 
349 /*
350  * Return an inode number between PROC_DYNAMIC_FIRST and
351  * 0xffffffff, or zero on failure.
352  */
proc_alloc_inum(unsigned int * inum)353 int proc_alloc_inum(unsigned int *inum)
354 {
355 	unsigned int i;
356 	int error;
357 
358 retry:
359 	if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL))
360 		return -ENOMEM;
361 
362 	spin_lock_irq(&proc_inum_lock);
363 	error = ida_get_new(&proc_inum_ida, &i);
364 	spin_unlock_irq(&proc_inum_lock);
365 	if (error == -EAGAIN)
366 		goto retry;
367 	else if (error)
368 		return error;
369 
370 	if (i > UINT_MAX - PROC_DYNAMIC_FIRST) {
371 		spin_lock_irq(&proc_inum_lock);
372 		ida_remove(&proc_inum_ida, i);
373 		spin_unlock_irq(&proc_inum_lock);
374 		return -ENOSPC;
375 	}
376 	*inum = PROC_DYNAMIC_FIRST + i;
377 	return 0;
378 }
379 
proc_free_inum(unsigned int inum)380 void proc_free_inum(unsigned int inum)
381 {
382 	unsigned long flags;
383 	spin_lock_irqsave(&proc_inum_lock, flags);
384 	ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
385 	spin_unlock_irqrestore(&proc_inum_lock, flags);
386 }
387 
proc_follow_link(struct dentry * dentry,struct nameidata * nd)388 static void *proc_follow_link(struct dentry *dentry, struct nameidata *nd)
389 {
390 	nd_set_link(nd, PDE(dentry->d_inode)->data);
391 	return NULL;
392 }
393 
394 static const struct inode_operations proc_link_inode_operations = {
395 	.readlink	= generic_readlink,
396 	.follow_link	= proc_follow_link,
397 };
398 
399 /*
400  * As some entries in /proc are volatile, we want to
401  * get rid of unused dentries.  This could be made
402  * smarter: we could keep a "volatile" flag in the
403  * inode to indicate which ones to keep.
404  */
proc_delete_dentry(const struct dentry * dentry)405 static int proc_delete_dentry(const struct dentry * dentry)
406 {
407 	return 1;
408 }
409 
410 static const struct dentry_operations proc_dentry_operations =
411 {
412 	.d_delete	= proc_delete_dentry,
413 };
414 
415 /*
416  * Don't create negative dentries here, return -ENOENT by hand
417  * instead.
418  */
proc_lookup_de(struct proc_dir_entry * de,struct inode * dir,struct dentry * dentry)419 struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
420 		struct dentry *dentry)
421 {
422 	struct inode *inode = NULL;
423 	int error = -ENOENT;
424 
425 	spin_lock(&proc_subdir_lock);
426 	for (de = de->subdir; de ; de = de->next) {
427 		if (de->namelen != dentry->d_name.len)
428 			continue;
429 		if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
430 			pde_get(de);
431 			spin_unlock(&proc_subdir_lock);
432 			error = -EINVAL;
433 			inode = proc_get_inode(dir->i_sb, de);
434 			goto out_unlock;
435 		}
436 	}
437 	spin_unlock(&proc_subdir_lock);
438 out_unlock:
439 
440 	if (inode) {
441 		d_set_d_op(dentry, &proc_dentry_operations);
442 		d_add(dentry, inode);
443 		return NULL;
444 	}
445 	if (de)
446 		pde_put(de);
447 	return ERR_PTR(error);
448 }
449 
proc_lookup(struct inode * dir,struct dentry * dentry,struct nameidata * nd)450 struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
451 		struct nameidata *nd)
452 {
453 	return proc_lookup_de(PDE(dir), dir, dentry);
454 }
455 
456 /*
457  * This returns non-zero if at EOF, so that the /proc
458  * root directory can use this and check if it should
459  * continue with the <pid> entries..
460  *
461  * Note that the VFS-layer doesn't care about the return
462  * value of the readdir() call, as long as it's non-negative
463  * for success..
464  */
proc_readdir_de(struct proc_dir_entry * de,struct file * filp,void * dirent,filldir_t filldir)465 int proc_readdir_de(struct proc_dir_entry *de, struct file *filp, void *dirent,
466 		filldir_t filldir)
467 {
468 	unsigned int ino;
469 	int i;
470 	struct inode *inode = filp->f_path.dentry->d_inode;
471 	int ret = 0;
472 
473 	ino = inode->i_ino;
474 	i = filp->f_pos;
475 	switch (i) {
476 		case 0:
477 			if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
478 				goto out;
479 			i++;
480 			filp->f_pos++;
481 			/* fall through */
482 		case 1:
483 			if (filldir(dirent, "..", 2, i,
484 				    parent_ino(filp->f_path.dentry),
485 				    DT_DIR) < 0)
486 				goto out;
487 			i++;
488 			filp->f_pos++;
489 			/* fall through */
490 		default:
491 			spin_lock(&proc_subdir_lock);
492 			de = de->subdir;
493 			i -= 2;
494 			for (;;) {
495 				if (!de) {
496 					ret = 1;
497 					spin_unlock(&proc_subdir_lock);
498 					goto out;
499 				}
500 				if (!i)
501 					break;
502 				de = de->next;
503 				i--;
504 			}
505 
506 			do {
507 				struct proc_dir_entry *next;
508 
509 				/* filldir passes info to user space */
510 				pde_get(de);
511 				spin_unlock(&proc_subdir_lock);
512 				if (filldir(dirent, de->name, de->namelen, filp->f_pos,
513 					    de->low_ino, de->mode >> 12) < 0) {
514 					pde_put(de);
515 					goto out;
516 				}
517 				spin_lock(&proc_subdir_lock);
518 				filp->f_pos++;
519 				next = de->next;
520 				pde_put(de);
521 				de = next;
522 			} while (de);
523 			spin_unlock(&proc_subdir_lock);
524 	}
525 	ret = 1;
526 out:
527 	return ret;
528 }
529 
proc_readdir(struct file * filp,void * dirent,filldir_t filldir)530 int proc_readdir(struct file *filp, void *dirent, filldir_t filldir)
531 {
532 	struct inode *inode = filp->f_path.dentry->d_inode;
533 
534 	return proc_readdir_de(PDE(inode), filp, dirent, filldir);
535 }
536 
537 /*
538  * These are the generic /proc directory operations. They
539  * use the in-memory "struct proc_dir_entry" tree to parse
540  * the /proc directory.
541  */
542 static const struct file_operations proc_dir_operations = {
543 	.llseek			= generic_file_llseek,
544 	.read			= generic_read_dir,
545 	.readdir		= proc_readdir,
546 };
547 
548 /*
549  * proc directories can do almost nothing..
550  */
551 static const struct inode_operations proc_dir_inode_operations = {
552 	.lookup		= proc_lookup,
553 	.getattr	= proc_getattr,
554 	.setattr	= proc_notify_change,
555 };
556 
proc_register(struct proc_dir_entry * dir,struct proc_dir_entry * dp)557 static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
558 {
559 	struct proc_dir_entry *tmp;
560 	int ret;
561 
562 	ret = proc_alloc_inum(&dp->low_ino);
563 	if (ret)
564 		return ret;
565 
566 	if (S_ISDIR(dp->mode)) {
567 		if (dp->proc_iops == NULL) {
568 			dp->proc_fops = &proc_dir_operations;
569 			dp->proc_iops = &proc_dir_inode_operations;
570 		}
571 		dir->nlink++;
572 	} else if (S_ISLNK(dp->mode)) {
573 		if (dp->proc_iops == NULL)
574 			dp->proc_iops = &proc_link_inode_operations;
575 	} else if (S_ISREG(dp->mode)) {
576 		if (dp->proc_fops == NULL)
577 			dp->proc_fops = &proc_file_operations;
578 		if (dp->proc_iops == NULL)
579 			dp->proc_iops = &proc_file_inode_operations;
580 	}
581 
582 	spin_lock(&proc_subdir_lock);
583 
584 	for (tmp = dir->subdir; tmp; tmp = tmp->next)
585 		if (strcmp(tmp->name, dp->name) == 0) {
586 			WARN(1, KERN_WARNING "proc_dir_entry '%s/%s' already registered\n",
587 				dir->name, dp->name);
588 			break;
589 		}
590 
591 	dp->next = dir->subdir;
592 	dp->parent = dir;
593 	dir->subdir = dp;
594 	spin_unlock(&proc_subdir_lock);
595 
596 	return 0;
597 }
598 
__proc_create(struct proc_dir_entry ** parent,const char * name,umode_t mode,nlink_t nlink)599 static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
600 					  const char *name,
601 					  umode_t mode,
602 					  nlink_t nlink)
603 {
604 	struct proc_dir_entry *ent = NULL;
605 	const char *fn = name;
606 	unsigned int len;
607 
608 	/* make sure name is valid */
609 	if (!name || !strlen(name)) goto out;
610 
611 	if (xlate_proc_name(name, parent, &fn) != 0)
612 		goto out;
613 
614 	/* At this point there must not be any '/' characters beyond *fn */
615 	if (strchr(fn, '/'))
616 		goto out;
617 
618 	len = strlen(fn);
619 
620 	ent = kmalloc(sizeof(struct proc_dir_entry) + len + 1, GFP_KERNEL);
621 	if (!ent) goto out;
622 
623 	memset(ent, 0, sizeof(struct proc_dir_entry));
624 	memcpy(ent->name, fn, len + 1);
625 	ent->namelen = len;
626 	ent->mode = mode;
627 	ent->nlink = nlink;
628 	atomic_set(&ent->count, 1);
629 	ent->pde_users = 0;
630 	spin_lock_init(&ent->pde_unload_lock);
631 	ent->pde_unload_completion = NULL;
632 	INIT_LIST_HEAD(&ent->pde_openers);
633  out:
634 	return ent;
635 }
636 
proc_symlink(const char * name,struct proc_dir_entry * parent,const char * dest)637 struct proc_dir_entry *proc_symlink(const char *name,
638 		struct proc_dir_entry *parent, const char *dest)
639 {
640 	struct proc_dir_entry *ent;
641 
642 	ent = __proc_create(&parent, name,
643 			  (S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
644 
645 	if (ent) {
646 		ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
647 		if (ent->data) {
648 			strcpy((char*)ent->data,dest);
649 			if (proc_register(parent, ent) < 0) {
650 				kfree(ent->data);
651 				kfree(ent);
652 				ent = NULL;
653 			}
654 		} else {
655 			kfree(ent);
656 			ent = NULL;
657 		}
658 	}
659 	return ent;
660 }
661 EXPORT_SYMBOL(proc_symlink);
662 
proc_mkdir_mode(const char * name,umode_t mode,struct proc_dir_entry * parent)663 struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
664 		struct proc_dir_entry *parent)
665 {
666 	struct proc_dir_entry *ent;
667 
668 	ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
669 	if (ent) {
670 		if (proc_register(parent, ent) < 0) {
671 			kfree(ent);
672 			ent = NULL;
673 		}
674 	}
675 	return ent;
676 }
677 EXPORT_SYMBOL(proc_mkdir_mode);
678 
proc_net_mkdir(struct net * net,const char * name,struct proc_dir_entry * parent)679 struct proc_dir_entry *proc_net_mkdir(struct net *net, const char *name,
680 		struct proc_dir_entry *parent)
681 {
682 	struct proc_dir_entry *ent;
683 
684 	ent = __proc_create(&parent, name, S_IFDIR | S_IRUGO | S_IXUGO, 2);
685 	if (ent) {
686 		ent->data = net;
687 		if (proc_register(parent, ent) < 0) {
688 			kfree(ent);
689 			ent = NULL;
690 		}
691 	}
692 	return ent;
693 }
694 EXPORT_SYMBOL_GPL(proc_net_mkdir);
695 
proc_mkdir(const char * name,struct proc_dir_entry * parent)696 struct proc_dir_entry *proc_mkdir(const char *name,
697 		struct proc_dir_entry *parent)
698 {
699 	return proc_mkdir_mode(name, S_IRUGO | S_IXUGO, parent);
700 }
701 EXPORT_SYMBOL(proc_mkdir);
702 
create_proc_entry(const char * name,umode_t mode,struct proc_dir_entry * parent)703 struct proc_dir_entry *create_proc_entry(const char *name, umode_t mode,
704 					 struct proc_dir_entry *parent)
705 {
706 	struct proc_dir_entry *ent;
707 	nlink_t nlink;
708 
709 	if (S_ISDIR(mode)) {
710 		if ((mode & S_IALLUGO) == 0)
711 			mode |= S_IRUGO | S_IXUGO;
712 		nlink = 2;
713 	} else {
714 		if ((mode & S_IFMT) == 0)
715 			mode |= S_IFREG;
716 		if ((mode & S_IALLUGO) == 0)
717 			mode |= S_IRUGO;
718 		nlink = 1;
719 	}
720 
721 	ent = __proc_create(&parent, name, mode, nlink);
722 	if (ent) {
723 		if (proc_register(parent, ent) < 0) {
724 			kfree(ent);
725 			ent = NULL;
726 		}
727 	}
728 	return ent;
729 }
730 EXPORT_SYMBOL(create_proc_entry);
731 
proc_create_data(const char * name,umode_t mode,struct proc_dir_entry * parent,const struct file_operations * proc_fops,void * data)732 struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
733 					struct proc_dir_entry *parent,
734 					const struct file_operations *proc_fops,
735 					void *data)
736 {
737 	struct proc_dir_entry *pde;
738 	nlink_t nlink;
739 
740 	if (S_ISDIR(mode)) {
741 		if ((mode & S_IALLUGO) == 0)
742 			mode |= S_IRUGO | S_IXUGO;
743 		nlink = 2;
744 	} else {
745 		if ((mode & S_IFMT) == 0)
746 			mode |= S_IFREG;
747 		if ((mode & S_IALLUGO) == 0)
748 			mode |= S_IRUGO;
749 		nlink = 1;
750 	}
751 
752 	pde = __proc_create(&parent, name, mode, nlink);
753 	if (!pde)
754 		goto out;
755 	pde->proc_fops = proc_fops;
756 	pde->data = data;
757 	if (proc_register(parent, pde) < 0)
758 		goto out_free;
759 	return pde;
760 out_free:
761 	kfree(pde);
762 out:
763 	return NULL;
764 }
765 EXPORT_SYMBOL(proc_create_data);
766 
free_proc_entry(struct proc_dir_entry * de)767 static void free_proc_entry(struct proc_dir_entry *de)
768 {
769 	proc_free_inum(de->low_ino);
770 
771 	if (S_ISLNK(de->mode))
772 		kfree(de->data);
773 	kfree(de);
774 }
775 
pde_put(struct proc_dir_entry * pde)776 void pde_put(struct proc_dir_entry *pde)
777 {
778 	if (atomic_dec_and_test(&pde->count))
779 		free_proc_entry(pde);
780 }
781 
782 /*
783  * Remove a /proc entry and free it if it's not currently in use.
784  */
remove_proc_entry(const char * name,struct proc_dir_entry * parent)785 void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
786 {
787 	struct proc_dir_entry **p;
788 	struct proc_dir_entry *de = NULL;
789 	const char *fn = name;
790 	unsigned int len;
791 
792 	spin_lock(&proc_subdir_lock);
793 	if (__xlate_proc_name(name, &parent, &fn) != 0) {
794 		spin_unlock(&proc_subdir_lock);
795 		return;
796 	}
797 	len = strlen(fn);
798 
799 	for (p = &parent->subdir; *p; p=&(*p)->next ) {
800 		if (proc_match(len, fn, *p)) {
801 			de = *p;
802 			*p = de->next;
803 			de->next = NULL;
804 			break;
805 		}
806 	}
807 	spin_unlock(&proc_subdir_lock);
808 	if (!de) {
809 		WARN(1, "name '%s'\n", name);
810 		return;
811 	}
812 
813 	spin_lock(&de->pde_unload_lock);
814 	/*
815 	 * Stop accepting new callers into module. If you're
816 	 * dynamically allocating ->proc_fops, save a pointer somewhere.
817 	 */
818 	de->proc_fops = NULL;
819 	/* Wait until all existing callers into module are done. */
820 	if (de->pde_users > 0) {
821 		DECLARE_COMPLETION_ONSTACK(c);
822 
823 		if (!de->pde_unload_completion)
824 			de->pde_unload_completion = &c;
825 
826 		spin_unlock(&de->pde_unload_lock);
827 
828 		wait_for_completion(de->pde_unload_completion);
829 
830 		spin_lock(&de->pde_unload_lock);
831 	}
832 
833 	while (!list_empty(&de->pde_openers)) {
834 		struct pde_opener *pdeo;
835 
836 		pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);
837 		list_del(&pdeo->lh);
838 		spin_unlock(&de->pde_unload_lock);
839 		pdeo->release(pdeo->inode, pdeo->file);
840 		kfree(pdeo);
841 		spin_lock(&de->pde_unload_lock);
842 	}
843 	spin_unlock(&de->pde_unload_lock);
844 
845 	if (S_ISDIR(de->mode))
846 		parent->nlink--;
847 	de->nlink = 0;
848 	WARN(de->subdir, KERN_WARNING "%s: removing non-empty directory "
849 			"'%s/%s', leaking at least '%s'\n", __func__,
850 			de->parent->name, de->name, de->subdir->name);
851 	pde_put(de);
852 }
853 EXPORT_SYMBOL(remove_proc_entry);
854