2 * proc/fs/generic.c --- generic routines for the proc-fs
4 * This file contains generic proc-fs routines for handling
5 * directories and files.
7 * Copyright (C) 1991, 1992 Linus Torvalds.
8 * Copyright (C) 1997 Theodore Ts'o
11 #include <linux/errno.h>
12 #include <linux/time.h>
13 #include <linux/proc_fs.h>
14 #include <linux/stat.h>
15 #include <linux/module.h>
16 #include <linux/mount.h>
17 #include <linux/smp_lock.h>
18 #include <linux/init.h>
19 #include <linux/idr.h>
20 #include <linux/namei.h>
21 #include <linux/bitops.h>
22 #include <linux/spinlock.h>
23 #include <linux/completion.h>
24 #include <asm/uaccess.h>
28 DEFINE_SPINLOCK(proc_subdir_lock
);
30 static int proc_match(int len
, const char *name
, struct proc_dir_entry
*de
)
32 if (de
->namelen
!= len
)
34 return !memcmp(name
, de
->name
, len
);
37 /* buffer size is one page but our output routines use some slack for overruns */
38 #define PROC_BLOCK_SIZE (PAGE_SIZE - 1024)
41 proc_file_read(struct file
*file
, char __user
*buf
, size_t nbytes
,
44 struct inode
* inode
= file
->f_path
.dentry
->d_inode
;
50 struct proc_dir_entry
* dp
;
51 unsigned long long pos
;
54 * Gaah, please just use "seq_file" instead. The legacy /proc
55 * interfaces cut loff_t down to off_t for reads, and ignore
56 * the offset entirely for writes..
59 if (pos
> MAX_NON_LFS
)
61 if (nbytes
> MAX_NON_LFS
- pos
)
62 nbytes
= MAX_NON_LFS
- pos
;
65 if (!(page
= (char*) __get_free_page(GFP_TEMPORARY
)))
68 while ((nbytes
> 0) && !eof
) {
69 count
= min_t(size_t, PROC_BLOCK_SIZE
, nbytes
);
73 /* Handle old net routines */
74 n
= dp
->get_info(page
, &start
, *ppos
, count
);
77 } else if (dp
->read_proc
) {
79 * How to be a proc read function
80 * ------------------------------
82 * int f(char *buffer, char **start, off_t offset,
83 * int count, int *peof, void *dat)
85 * Assume that the buffer is "count" bytes in size.
87 * If you know you have supplied all the data you
90 * You have three ways to return data:
91 * 0) Leave *start = NULL. (This is the default.)
92 * Put the data of the requested offset at that
93 * offset within the buffer. Return the number (n)
94 * of bytes there are from the beginning of the
95 * buffer up to the last byte of data. If the
96 * number of supplied bytes (= n - offset) is
97 * greater than zero and you didn't signal eof
98 * and the reader is prepared to take more data
99 * you will be called again with the requested
100 * offset advanced by the number of bytes
101 * absorbed. This interface is useful for files
102 * no larger than the buffer.
103 * 1) Set *start = an unsigned long value less than
104 * the buffer address but greater than zero.
105 * Put the data of the requested offset at the
106 * beginning of the buffer. Return the number of
107 * bytes of data placed there. If this number is
108 * greater than zero and you didn't signal eof
109 * and the reader is prepared to take more data
110 * you will be called again with the requested
111 * offset advanced by *start. This interface is
112 * useful when you have a large file consisting
113 * of a series of blocks which you want to count
114 * and return as wholes.
115 * (Hack by Paul.Russell@rustcorp.com.au)
116 * 2) Set *start = an address within the buffer.
117 * Put the data of the requested offset at *start.
118 * Return the number of bytes of data placed there.
119 * If this number is greater than zero and you
120 * didn't signal eof and the reader is prepared to
121 * take more data you will be called again with the
122 * requested offset advanced by the number of bytes
125 n
= dp
->read_proc(page
, &start
, *ppos
,
126 count
, &eof
, dp
->data
);
130 if (n
== 0) /* end of file */
132 if (n
< 0) { /* error */
141 "proc_file_read: Apparent buffer overflow!\n");
149 start
= page
+ *ppos
;
150 } else if (start
< page
) {
153 "proc_file_read: Apparent buffer overflow!\n");
158 * Don't reduce n because doing so might
159 * cut off part of a data block.
162 "proc_file_read: Read count exceeded\n");
164 } else /* start >= page */ {
165 unsigned long startoff
= (unsigned long)(start
- page
);
166 if (n
> (PAGE_SIZE
- startoff
)) {
168 "proc_file_read: Apparent buffer overflow!\n");
169 n
= PAGE_SIZE
- startoff
;
175 n
-= copy_to_user(buf
, start
< page
? page
: start
, n
);
182 *ppos
+= start
< page
? (unsigned long)start
: n
;
187 free_page((unsigned long) page
);
192 proc_file_write(struct file
*file
, const char __user
*buffer
,
193 size_t count
, loff_t
*ppos
)
195 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
196 struct proc_dir_entry
* dp
;
203 /* FIXME: does this routine need ppos? probably... */
204 return dp
->write_proc(file
, buffer
, count
, dp
->data
);
209 proc_file_lseek(struct file
*file
, loff_t offset
, int orig
)
211 loff_t retval
= -EINVAL
;
214 offset
+= file
->f_pos
;
217 if (offset
< 0 || offset
> MAX_NON_LFS
)
219 file
->f_pos
= retval
= offset
;
224 static const struct file_operations proc_file_operations
= {
225 .llseek
= proc_file_lseek
,
226 .read
= proc_file_read
,
227 .write
= proc_file_write
,
230 static int proc_notify_change(struct dentry
*dentry
, struct iattr
*iattr
)
232 struct inode
*inode
= dentry
->d_inode
;
233 struct proc_dir_entry
*de
= PDE(inode
);
236 error
= inode_change_ok(inode
, iattr
);
240 error
= inode_setattr(inode
, iattr
);
244 de
->uid
= inode
->i_uid
;
245 de
->gid
= inode
->i_gid
;
246 de
->mode
= inode
->i_mode
;
251 static int proc_getattr(struct vfsmount
*mnt
, struct dentry
*dentry
,
254 struct inode
*inode
= dentry
->d_inode
;
255 struct proc_dir_entry
*de
= PROC_I(inode
)->pde
;
257 inode
->i_nlink
= de
->nlink
;
259 generic_fillattr(inode
, stat
);
263 static const struct inode_operations proc_file_inode_operations
= {
264 .setattr
= proc_notify_change
,
268 * This function parses a name such as "tty/driver/serial", and
269 * returns the struct proc_dir_entry for "/proc/tty/driver", and
270 * returns "serial" in residual.
272 static int xlate_proc_name(const char *name
,
273 struct proc_dir_entry
**ret
, const char **residual
)
275 const char *cp
= name
, *next
;
276 struct proc_dir_entry
*de
;
284 spin_lock(&proc_subdir_lock
);
286 next
= strchr(cp
, '/');
291 for (de
= de
->subdir
; de
; de
= de
->next
) {
292 if (proc_match(len
, cp
, de
))
304 spin_unlock(&proc_subdir_lock
);
308 static DEFINE_IDR(proc_inum_idr
);
309 static DEFINE_SPINLOCK(proc_inum_lock
); /* protects the above */
311 #define PROC_DYNAMIC_FIRST 0xF0000000UL
314 * Return an inode number between PROC_DYNAMIC_FIRST and
315 * 0xffffffff, or zero on failure.
317 static unsigned int get_inode_number(void)
323 if (idr_pre_get(&proc_inum_idr
, GFP_KERNEL
) == 0)
326 spin_lock(&proc_inum_lock
);
327 error
= idr_get_new(&proc_inum_idr
, NULL
, &i
);
328 spin_unlock(&proc_inum_lock
);
329 if (error
== -EAGAIN
)
334 inum
= (i
& MAX_ID_MASK
) + PROC_DYNAMIC_FIRST
;
336 /* inum will never be more than 0xf0ffffff, so no check
343 static void release_inode_number(unsigned int inum
)
345 int id
= (inum
- PROC_DYNAMIC_FIRST
) | ~MAX_ID_MASK
;
347 spin_lock(&proc_inum_lock
);
348 idr_remove(&proc_inum_idr
, id
);
349 spin_unlock(&proc_inum_lock
);
352 static void *proc_follow_link(struct dentry
*dentry
, struct nameidata
*nd
)
354 nd_set_link(nd
, PDE(dentry
->d_inode
)->data
);
358 static const struct inode_operations proc_link_inode_operations
= {
359 .readlink
= generic_readlink
,
360 .follow_link
= proc_follow_link
,
364 * As some entries in /proc are volatile, we want to
365 * get rid of unused dentries. This could be made
366 * smarter: we could keep a "volatile" flag in the
367 * inode to indicate which ones to keep.
369 static int proc_delete_dentry(struct dentry
* dentry
)
374 static struct dentry_operations proc_dentry_operations
=
376 .d_delete
= proc_delete_dentry
,
380 * Don't create negative dentries here, return -ENOENT by hand
383 struct dentry
*proc_lookup_de(struct proc_dir_entry
*de
, struct inode
*dir
,
384 struct dentry
*dentry
)
386 struct inode
*inode
= NULL
;
390 spin_lock(&proc_subdir_lock
);
391 for (de
= de
->subdir
; de
; de
= de
->next
) {
392 if (de
->namelen
!= dentry
->d_name
.len
)
394 if (!memcmp(dentry
->d_name
.name
, de
->name
, de
->namelen
)) {
399 spin_unlock(&proc_subdir_lock
);
401 inode
= proc_get_inode(dir
->i_sb
, ino
, de
);
405 spin_unlock(&proc_subdir_lock
);
410 dentry
->d_op
= &proc_dentry_operations
;
411 d_add(dentry
, inode
);
416 return ERR_PTR(error
);
419 struct dentry
*proc_lookup(struct inode
*dir
, struct dentry
*dentry
,
420 struct nameidata
*nd
)
422 return proc_lookup_de(PDE(dir
), dir
, dentry
);
426 * This returns non-zero if at EOF, so that the /proc
427 * root directory can use this and check if it should
428 * continue with the <pid> entries..
430 * Note that the VFS-layer doesn't care about the return
431 * value of the readdir() call, as long as it's non-negative
434 int proc_readdir_de(struct proc_dir_entry
*de
, struct file
*filp
, void *dirent
,
439 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
448 if (filldir(dirent
, ".", 1, i
, ino
, DT_DIR
) < 0)
454 if (filldir(dirent
, "..", 2, i
,
455 parent_ino(filp
->f_path
.dentry
),
462 spin_lock(&proc_subdir_lock
);
468 spin_unlock(&proc_subdir_lock
);
478 struct proc_dir_entry
*next
;
480 /* filldir passes info to user space */
482 spin_unlock(&proc_subdir_lock
);
483 if (filldir(dirent
, de
->name
, de
->namelen
, filp
->f_pos
,
484 de
->low_ino
, de
->mode
>> 12) < 0) {
488 spin_lock(&proc_subdir_lock
);
494 spin_unlock(&proc_subdir_lock
);
497 out
: unlock_kernel();
501 int proc_readdir(struct file
*filp
, void *dirent
, filldir_t filldir
)
503 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
505 return proc_readdir_de(PDE(inode
), filp
, dirent
, filldir
);
509 * These are the generic /proc directory operations. They
510 * use the in-memory "struct proc_dir_entry" tree to parse
511 * the /proc directory.
513 static const struct file_operations proc_dir_operations
= {
514 .read
= generic_read_dir
,
515 .readdir
= proc_readdir
,
519 * proc directories can do almost nothing..
521 static const struct inode_operations proc_dir_inode_operations
= {
522 .lookup
= proc_lookup
,
523 .getattr
= proc_getattr
,
524 .setattr
= proc_notify_change
,
527 static int proc_register(struct proc_dir_entry
* dir
, struct proc_dir_entry
* dp
)
530 struct proc_dir_entry
*tmp
;
532 i
= get_inode_number();
537 if (S_ISDIR(dp
->mode
)) {
538 if (dp
->proc_iops
== NULL
) {
539 dp
->proc_fops
= &proc_dir_operations
;
540 dp
->proc_iops
= &proc_dir_inode_operations
;
543 } else if (S_ISLNK(dp
->mode
)) {
544 if (dp
->proc_iops
== NULL
)
545 dp
->proc_iops
= &proc_link_inode_operations
;
546 } else if (S_ISREG(dp
->mode
)) {
547 if (dp
->proc_fops
== NULL
)
548 dp
->proc_fops
= &proc_file_operations
;
549 if (dp
->proc_iops
== NULL
)
550 dp
->proc_iops
= &proc_file_inode_operations
;
553 spin_lock(&proc_subdir_lock
);
555 for (tmp
= dir
->subdir
; tmp
; tmp
= tmp
->next
)
556 if (strcmp(tmp
->name
, dp
->name
) == 0) {
557 printk(KERN_WARNING
"proc_dir_entry '%s' already "
558 "registered\n", dp
->name
);
563 dp
->next
= dir
->subdir
;
566 spin_unlock(&proc_subdir_lock
);
571 static struct proc_dir_entry
*__proc_create(struct proc_dir_entry
**parent
,
576 struct proc_dir_entry
*ent
= NULL
;
577 const char *fn
= name
;
580 /* make sure name is valid */
581 if (!name
|| !strlen(name
)) goto out
;
583 if (xlate_proc_name(name
, parent
, &fn
) != 0)
586 /* At this point there must not be any '/' characters beyond *fn */
592 ent
= kmalloc(sizeof(struct proc_dir_entry
) + len
+ 1, GFP_KERNEL
);
595 memset(ent
, 0, sizeof(struct proc_dir_entry
));
596 memcpy(((char *) ent
) + sizeof(struct proc_dir_entry
), fn
, len
+ 1);
597 ent
->name
= ((char *) ent
) + sizeof(*ent
);
601 atomic_set(&ent
->count
, 1);
603 spin_lock_init(&ent
->pde_unload_lock
);
604 ent
->pde_unload_completion
= NULL
;
609 struct proc_dir_entry
*proc_symlink(const char *name
,
610 struct proc_dir_entry
*parent
, const char *dest
)
612 struct proc_dir_entry
*ent
;
614 ent
= __proc_create(&parent
, name
,
615 (S_IFLNK
| S_IRUGO
| S_IWUGO
| S_IXUGO
),1);
618 ent
->data
= kmalloc((ent
->size
=strlen(dest
))+1, GFP_KERNEL
);
620 strcpy((char*)ent
->data
,dest
);
621 if (proc_register(parent
, ent
) < 0) {
634 struct proc_dir_entry
*proc_mkdir_mode(const char *name
, mode_t mode
,
635 struct proc_dir_entry
*parent
)
637 struct proc_dir_entry
*ent
;
639 ent
= __proc_create(&parent
, name
, S_IFDIR
| mode
, 2);
641 if (proc_register(parent
, ent
) < 0) {
649 struct proc_dir_entry
*proc_mkdir(const char *name
,
650 struct proc_dir_entry
*parent
)
652 return proc_mkdir_mode(name
, S_IRUGO
| S_IXUGO
, parent
);
655 struct proc_dir_entry
*create_proc_entry(const char *name
, mode_t mode
,
656 struct proc_dir_entry
*parent
)
658 struct proc_dir_entry
*ent
;
662 if ((mode
& S_IALLUGO
) == 0)
663 mode
|= S_IRUGO
| S_IXUGO
;
666 if ((mode
& S_IFMT
) == 0)
668 if ((mode
& S_IALLUGO
) == 0)
673 ent
= __proc_create(&parent
, name
, mode
, nlink
);
675 if (proc_register(parent
, ent
) < 0) {
683 struct proc_dir_entry
*proc_create(const char *name
, mode_t mode
,
684 struct proc_dir_entry
*parent
,
685 const struct file_operations
*proc_fops
)
687 struct proc_dir_entry
*pde
;
691 if ((mode
& S_IALLUGO
) == 0)
692 mode
|= S_IRUGO
| S_IXUGO
;
695 if ((mode
& S_IFMT
) == 0)
697 if ((mode
& S_IALLUGO
) == 0)
702 pde
= __proc_create(&parent
, name
, mode
, nlink
);
705 pde
->proc_fops
= proc_fops
;
706 if (proc_register(parent
, pde
) < 0)
715 void free_proc_entry(struct proc_dir_entry
*de
)
717 unsigned int ino
= de
->low_ino
;
719 if (ino
< PROC_DYNAMIC_FIRST
)
722 release_inode_number(ino
);
724 if (S_ISLNK(de
->mode
))
730 * Remove a /proc entry and free it if it's not currently in use.
732 void remove_proc_entry(const char *name
, struct proc_dir_entry
*parent
)
734 struct proc_dir_entry
**p
;
735 struct proc_dir_entry
*de
= NULL
;
736 const char *fn
= name
;
739 if (xlate_proc_name(name
, &parent
, &fn
) != 0)
743 spin_lock(&proc_subdir_lock
);
744 for (p
= &parent
->subdir
; *p
; p
=&(*p
)->next
) {
745 if (proc_match(len
, fn
, *p
)) {
752 spin_unlock(&proc_subdir_lock
);
756 spin_lock(&de
->pde_unload_lock
);
758 * Stop accepting new callers into module. If you're
759 * dynamically allocating ->proc_fops, save a pointer somewhere.
761 de
->proc_fops
= NULL
;
762 /* Wait until all existing callers into module are done. */
763 if (de
->pde_users
> 0) {
764 DECLARE_COMPLETION_ONSTACK(c
);
766 if (!de
->pde_unload_completion
)
767 de
->pde_unload_completion
= &c
;
769 spin_unlock(&de
->pde_unload_lock
);
771 wait_for_completion(de
->pde_unload_completion
);
773 goto continue_removing
;
775 spin_unlock(&de
->pde_unload_lock
);
778 if (S_ISDIR(de
->mode
))
782 printk(KERN_WARNING
"%s: removing non-empty directory "
783 "'%s/%s', leaking at least '%s'\n", __func__
,
784 de
->parent
->name
, de
->name
, de
->subdir
->name
);
787 if (atomic_dec_and_test(&de
->count
))