2 * linux/fs/proc/inode.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
7 #include <linux/time.h>
8 #include <linux/proc_fs.h>
9 #include <linux/kernel.h>
11 #include <linux/string.h>
12 #include <linux/stat.h>
13 #include <linux/completion.h>
14 #include <linux/poll.h>
15 #include <linux/file.h>
16 #include <linux/limits.h>
17 #include <linux/init.h>
18 #include <linux/module.h>
19 #include <linux/sysctl.h>
20 #include <linux/slab.h>
22 #include <asm/system.h>
23 #include <asm/uaccess.h>
27 static void proc_evict_inode(struct inode
*inode
)
29 struct proc_dir_entry
*de
;
31 truncate_inode_pages(&inode
->i_data
, 0);
34 /* Stop tracking associated processes */
35 put_pid(PROC_I(inode
)->pid
);
37 /* Let go of any associated proc directory entry */
38 de
= PROC_I(inode
)->pde
;
41 if (PROC_I(inode
)->sysctl
)
42 sysctl_head_put(PROC_I(inode
)->sysctl
);
45 struct vfsmount
*proc_mnt
;
47 static struct kmem_cache
* proc_inode_cachep
;
49 static struct inode
*proc_alloc_inode(struct super_block
*sb
)
51 struct proc_inode
*ei
;
54 ei
= (struct proc_inode
*)kmem_cache_alloc(proc_inode_cachep
, GFP_KERNEL
);
59 ei
->op
.proc_get_link
= NULL
;
62 ei
->sysctl_entry
= NULL
;
63 inode
= &ei
->vfs_inode
;
64 inode
->i_mtime
= inode
->i_atime
= inode
->i_ctime
= CURRENT_TIME
;
68 static void proc_destroy_inode(struct inode
*inode
)
70 kmem_cache_free(proc_inode_cachep
, PROC_I(inode
));
73 static void init_once(void *foo
)
75 struct proc_inode
*ei
= (struct proc_inode
*) foo
;
77 inode_init_once(&ei
->vfs_inode
);
80 void __init
proc_init_inodecache(void)
82 proc_inode_cachep
= kmem_cache_create("proc_inode_cache",
83 sizeof(struct proc_inode
),
84 0, (SLAB_RECLAIM_ACCOUNT
|
85 SLAB_MEM_SPREAD
|SLAB_PANIC
),
89 static const struct super_operations proc_sops
= {
90 .alloc_inode
= proc_alloc_inode
,
91 .destroy_inode
= proc_destroy_inode
,
92 .drop_inode
= generic_delete_inode
,
93 .evict_inode
= proc_evict_inode
,
94 .statfs
= simple_statfs
,
97 static void __pde_users_dec(struct proc_dir_entry
*pde
)
100 if (pde
->pde_unload_completion
&& pde
->pde_users
== 0)
101 complete(pde
->pde_unload_completion
);
104 void pde_users_dec(struct proc_dir_entry
*pde
)
106 spin_lock(&pde
->pde_unload_lock
);
107 __pde_users_dec(pde
);
108 spin_unlock(&pde
->pde_unload_lock
);
111 static loff_t
proc_reg_llseek(struct file
*file
, loff_t offset
, int whence
)
113 struct proc_dir_entry
*pde
= PDE(file
->f_path
.dentry
->d_inode
);
115 loff_t (*llseek
)(struct file
*, loff_t
, int);
117 spin_lock(&pde
->pde_unload_lock
);
119 * remove_proc_entry() is going to delete PDE (as part of module
120 * cleanup sequence). No new callers into module allowed.
122 if (!pde
->proc_fops
) {
123 spin_unlock(&pde
->pde_unload_lock
);
127 * Bump refcount so that remove_proc_entry will wail for ->llseek to
132 * Save function pointer under lock, to protect against ->proc_fops
133 * NULL'ifying right after ->pde_unload_lock is dropped.
135 llseek
= pde
->proc_fops
->llseek
;
136 spin_unlock(&pde
->pde_unload_lock
);
139 llseek
= default_llseek
;
140 rv
= llseek(file
, offset
, whence
);
146 static ssize_t
proc_reg_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
148 struct proc_dir_entry
*pde
= PDE(file
->f_path
.dentry
->d_inode
);
150 ssize_t (*read
)(struct file
*, char __user
*, size_t, loff_t
*);
152 spin_lock(&pde
->pde_unload_lock
);
153 if (!pde
->proc_fops
) {
154 spin_unlock(&pde
->pde_unload_lock
);
158 read
= pde
->proc_fops
->read
;
159 spin_unlock(&pde
->pde_unload_lock
);
162 rv
= read(file
, buf
, count
, ppos
);
168 static ssize_t
proc_reg_write(struct file
*file
, const char __user
*buf
, size_t count
, loff_t
*ppos
)
170 struct proc_dir_entry
*pde
= PDE(file
->f_path
.dentry
->d_inode
);
172 ssize_t (*write
)(struct file
*, const char __user
*, size_t, loff_t
*);
174 spin_lock(&pde
->pde_unload_lock
);
175 if (!pde
->proc_fops
) {
176 spin_unlock(&pde
->pde_unload_lock
);
180 write
= pde
->proc_fops
->write
;
181 spin_unlock(&pde
->pde_unload_lock
);
184 rv
= write(file
, buf
, count
, ppos
);
190 static unsigned int proc_reg_poll(struct file
*file
, struct poll_table_struct
*pts
)
192 struct proc_dir_entry
*pde
= PDE(file
->f_path
.dentry
->d_inode
);
193 unsigned int rv
= DEFAULT_POLLMASK
;
194 unsigned int (*poll
)(struct file
*, struct poll_table_struct
*);
196 spin_lock(&pde
->pde_unload_lock
);
197 if (!pde
->proc_fops
) {
198 spin_unlock(&pde
->pde_unload_lock
);
202 poll
= pde
->proc_fops
->poll
;
203 spin_unlock(&pde
->pde_unload_lock
);
206 rv
= poll(file
, pts
);
212 static long proc_reg_unlocked_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
214 struct proc_dir_entry
*pde
= PDE(file
->f_path
.dentry
->d_inode
);
216 long (*ioctl
)(struct file
*, unsigned int, unsigned long);
218 spin_lock(&pde
->pde_unload_lock
);
219 if (!pde
->proc_fops
) {
220 spin_unlock(&pde
->pde_unload_lock
);
224 ioctl
= pde
->proc_fops
->unlocked_ioctl
;
225 spin_unlock(&pde
->pde_unload_lock
);
228 rv
= ioctl(file
, cmd
, arg
);
235 static long proc_reg_compat_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
237 struct proc_dir_entry
*pde
= PDE(file
->f_path
.dentry
->d_inode
);
239 long (*compat_ioctl
)(struct file
*, unsigned int, unsigned long);
241 spin_lock(&pde
->pde_unload_lock
);
242 if (!pde
->proc_fops
) {
243 spin_unlock(&pde
->pde_unload_lock
);
247 compat_ioctl
= pde
->proc_fops
->compat_ioctl
;
248 spin_unlock(&pde
->pde_unload_lock
);
251 rv
= compat_ioctl(file
, cmd
, arg
);
258 static int proc_reg_mmap(struct file
*file
, struct vm_area_struct
*vma
)
260 struct proc_dir_entry
*pde
= PDE(file
->f_path
.dentry
->d_inode
);
262 int (*mmap
)(struct file
*, struct vm_area_struct
*);
264 spin_lock(&pde
->pde_unload_lock
);
265 if (!pde
->proc_fops
) {
266 spin_unlock(&pde
->pde_unload_lock
);
270 mmap
= pde
->proc_fops
->mmap
;
271 spin_unlock(&pde
->pde_unload_lock
);
274 rv
= mmap(file
, vma
);
280 static int proc_reg_open(struct inode
*inode
, struct file
*file
)
282 struct proc_dir_entry
*pde
= PDE(inode
);
284 int (*open
)(struct inode
*, struct file
*);
285 int (*release
)(struct inode
*, struct file
*);
286 struct pde_opener
*pdeo
;
289 * What for, you ask? Well, we can have open, rmmod, remove_proc_entry
290 * sequence. ->release won't be called because ->proc_fops will be
291 * cleared. Depending on complexity of ->release, consequences vary.
293 * We can't wait for mercy when close will be done for real, it's
294 * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release
295 * by hand in remove_proc_entry(). For this, save opener's credentials
298 pdeo
= kmalloc(sizeof(struct pde_opener
), GFP_KERNEL
);
302 spin_lock(&pde
->pde_unload_lock
);
303 if (!pde
->proc_fops
) {
304 spin_unlock(&pde
->pde_unload_lock
);
309 open
= pde
->proc_fops
->open
;
310 release
= pde
->proc_fops
->release
;
311 spin_unlock(&pde
->pde_unload_lock
);
314 rv
= open(inode
, file
);
316 spin_lock(&pde
->pde_unload_lock
);
317 if (rv
== 0 && release
) {
318 /* To know what to release. */
321 /* Strictly for "too late" ->release in proc_reg_release(). */
322 pdeo
->release
= release
;
323 list_add(&pdeo
->lh
, &pde
->pde_openers
);
326 __pde_users_dec(pde
);
327 spin_unlock(&pde
->pde_unload_lock
);
331 static struct pde_opener
*find_pde_opener(struct proc_dir_entry
*pde
,
332 struct inode
*inode
, struct file
*file
)
334 struct pde_opener
*pdeo
;
336 list_for_each_entry(pdeo
, &pde
->pde_openers
, lh
) {
337 if (pdeo
->inode
== inode
&& pdeo
->file
== file
)
343 static int proc_reg_release(struct inode
*inode
, struct file
*file
)
345 struct proc_dir_entry
*pde
= PDE(inode
);
347 int (*release
)(struct inode
*, struct file
*);
348 struct pde_opener
*pdeo
;
350 spin_lock(&pde
->pde_unload_lock
);
351 pdeo
= find_pde_opener(pde
, inode
, file
);
352 if (!pde
->proc_fops
) {
354 * Can't simply exit, __fput() will think that everything is OK,
355 * and move on to freeing struct file. remove_proc_entry() will
356 * find slacker in opener's list and will try to do non-trivial
357 * things with struct file. Therefore, remove opener from list.
359 * But if opener is removed from list, who will ->release it?
363 spin_unlock(&pde
->pde_unload_lock
);
364 rv
= pdeo
->release(inode
, file
);
367 spin_unlock(&pde
->pde_unload_lock
);
371 release
= pde
->proc_fops
->release
;
376 spin_unlock(&pde
->pde_unload_lock
);
379 rv
= release(inode
, file
);
385 static const struct file_operations proc_reg_file_ops
= {
386 .llseek
= proc_reg_llseek
,
387 .read
= proc_reg_read
,
388 .write
= proc_reg_write
,
389 .poll
= proc_reg_poll
,
390 .unlocked_ioctl
= proc_reg_unlocked_ioctl
,
392 .compat_ioctl
= proc_reg_compat_ioctl
,
394 .mmap
= proc_reg_mmap
,
395 .open
= proc_reg_open
,
396 .release
= proc_reg_release
,
400 static const struct file_operations proc_reg_file_ops_no_compat
= {
401 .llseek
= proc_reg_llseek
,
402 .read
= proc_reg_read
,
403 .write
= proc_reg_write
,
404 .poll
= proc_reg_poll
,
405 .unlocked_ioctl
= proc_reg_unlocked_ioctl
,
406 .mmap
= proc_reg_mmap
,
407 .open
= proc_reg_open
,
408 .release
= proc_reg_release
,
412 struct inode
*proc_get_inode(struct super_block
*sb
, unsigned int ino
,
413 struct proc_dir_entry
*de
)
415 struct inode
* inode
;
417 inode
= iget_locked(sb
, ino
);
420 if (inode
->i_state
& I_NEW
) {
421 inode
->i_mtime
= inode
->i_atime
= inode
->i_ctime
= CURRENT_TIME
;
422 PROC_I(inode
)->fd
= 0;
423 PROC_I(inode
)->pde
= de
;
426 inode
->i_mode
= de
->mode
;
427 inode
->i_uid
= de
->uid
;
428 inode
->i_gid
= de
->gid
;
431 inode
->i_size
= de
->size
;
433 inode
->i_nlink
= de
->nlink
;
435 inode
->i_op
= de
->proc_iops
;
437 if (S_ISREG(inode
->i_mode
)) {
439 if (!de
->proc_fops
->compat_ioctl
)
441 &proc_reg_file_ops_no_compat
;
444 inode
->i_fop
= &proc_reg_file_ops
;
446 inode
->i_fop
= de
->proc_fops
;
449 unlock_new_inode(inode
);
455 int proc_fill_super(struct super_block
*s
)
457 struct inode
* root_inode
;
459 s
->s_flags
|= MS_NODIRATIME
| MS_NOSUID
| MS_NOEXEC
;
460 s
->s_blocksize
= 1024;
461 s
->s_blocksize_bits
= 10;
462 s
->s_magic
= PROC_SUPER_MAGIC
;
463 s
->s_op
= &proc_sops
;
467 root_inode
= proc_get_inode(s
, PROC_ROOT_INO
, &proc_root
);
470 root_inode
->i_uid
= 0;
471 root_inode
->i_gid
= 0;
472 s
->s_root
= d_alloc_root(root_inode
);
478 printk("proc_read_super: get root inode failed\n");