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>
10 #include <linux/pid_namespace.h>
12 #include <linux/string.h>
13 #include <linux/stat.h>
14 #include <linux/completion.h>
15 #include <linux/poll.h>
16 #include <linux/printk.h>
17 #include <linux/file.h>
18 #include <linux/limits.h>
19 #include <linux/init.h>
20 #include <linux/module.h>
21 #include <linux/sysctl.h>
22 #include <linux/seq_file.h>
23 #include <linux/slab.h>
24 #include <linux/mount.h>
25 #include <linux/magic.h>
27 #include <asm/uaccess.h>
31 static void proc_evict_inode(struct inode
*inode
)
33 struct proc_dir_entry
*de
;
34 struct ctl_table_header
*head
;
36 truncate_inode_pages_final(&inode
->i_data
);
39 /* Stop tracking associated processes */
40 put_pid(PROC_I(inode
)->pid
);
42 /* Let go of any associated proc directory entry */
46 head
= PROC_I(inode
)->sysctl
;
48 RCU_INIT_POINTER(PROC_I(inode
)->sysctl
, NULL
);
49 sysctl_head_put(head
);
53 static struct kmem_cache
* proc_inode_cachep
;
55 static struct inode
*proc_alloc_inode(struct super_block
*sb
)
57 struct proc_inode
*ei
;
60 ei
= (struct proc_inode
*)kmem_cache_alloc(proc_inode_cachep
, GFP_KERNEL
);
65 ei
->op
.proc_get_link
= NULL
;
68 ei
->sysctl_entry
= NULL
;
70 inode
= &ei
->vfs_inode
;
71 inode
->i_mtime
= inode
->i_atime
= inode
->i_ctime
= CURRENT_TIME
;
75 static void proc_i_callback(struct rcu_head
*head
)
77 struct inode
*inode
= container_of(head
, struct inode
, i_rcu
);
78 kmem_cache_free(proc_inode_cachep
, PROC_I(inode
));
81 static void proc_destroy_inode(struct inode
*inode
)
83 call_rcu(&inode
->i_rcu
, proc_i_callback
);
86 static void init_once(void *foo
)
88 struct proc_inode
*ei
= (struct proc_inode
*) foo
;
90 inode_init_once(&ei
->vfs_inode
);
93 void __init
proc_init_inodecache(void)
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
|
103 static int proc_show_options(struct seq_file
*seq
, struct dentry
*root
)
105 struct super_block
*sb
= root
->d_sb
;
106 struct pid_namespace
*pid
= sb
->s_fs_info
;
108 if (!gid_eq(pid
->pid_gid
, GLOBAL_ROOT_GID
))
109 seq_printf(seq
, ",gid=%u", from_kgid_munged(&init_user_ns
, pid
->pid_gid
));
110 if (pid
->hide_pid
!= 0)
111 seq_printf(seq
, ",hidepid=%u", pid
->hide_pid
);
116 static const struct super_operations proc_sops
= {
117 .alloc_inode
= proc_alloc_inode
,
118 .destroy_inode
= proc_destroy_inode
,
119 .drop_inode
= generic_delete_inode
,
120 .evict_inode
= proc_evict_inode
,
121 .statfs
= simple_statfs
,
122 .remount_fs
= proc_remount
,
123 .show_options
= proc_show_options
,
126 enum {BIAS
= -1U<<31};
128 static inline int use_pde(struct proc_dir_entry
*pde
)
130 return atomic_inc_unless_negative(&pde
->in_use
);
133 static void unuse_pde(struct proc_dir_entry
*pde
)
135 if (atomic_dec_return(&pde
->in_use
) == BIAS
)
136 complete(pde
->pde_unload_completion
);
140 static void close_pdeo(struct proc_dir_entry
*pde
, struct pde_opener
*pdeo
)
143 /* somebody else is doing that, just wait */
144 DECLARE_COMPLETION_ONSTACK(c
);
146 spin_unlock(&pde
->pde_unload_lock
);
147 wait_for_completion(&c
);
148 spin_lock(&pde
->pde_unload_lock
);
152 spin_unlock(&pde
->pde_unload_lock
);
154 pde
->proc_fops
->release(file_inode(file
), file
);
155 spin_lock(&pde
->pde_unload_lock
);
156 list_del_init(&pdeo
->lh
);
163 void proc_entry_rundown(struct proc_dir_entry
*de
)
165 DECLARE_COMPLETION_ONSTACK(c
);
166 /* Wait until all existing callers into module are done. */
167 de
->pde_unload_completion
= &c
;
168 if (atomic_add_return(BIAS
, &de
->in_use
) != BIAS
)
169 wait_for_completion(&c
);
171 spin_lock(&de
->pde_unload_lock
);
172 while (!list_empty(&de
->pde_openers
)) {
173 struct pde_opener
*pdeo
;
174 pdeo
= list_first_entry(&de
->pde_openers
, struct pde_opener
, lh
);
175 close_pdeo(de
, pdeo
);
177 spin_unlock(&de
->pde_unload_lock
);
180 static loff_t
proc_reg_llseek(struct file
*file
, loff_t offset
, int whence
)
182 struct proc_dir_entry
*pde
= PDE(file_inode(file
));
185 loff_t (*llseek
)(struct file
*, loff_t
, int);
186 llseek
= pde
->proc_fops
->llseek
;
188 llseek
= default_llseek
;
189 rv
= llseek(file
, offset
, whence
);
195 static ssize_t
proc_reg_read(struct file
*file
, char __user
*buf
, size_t count
, loff_t
*ppos
)
197 ssize_t (*read
)(struct file
*, char __user
*, size_t, loff_t
*);
198 struct proc_dir_entry
*pde
= PDE(file_inode(file
));
201 read
= pde
->proc_fops
->read
;
203 rv
= read(file
, buf
, count
, ppos
);
209 static ssize_t
proc_reg_write(struct file
*file
, const char __user
*buf
, size_t count
, loff_t
*ppos
)
211 ssize_t (*write
)(struct file
*, const char __user
*, size_t, loff_t
*);
212 struct proc_dir_entry
*pde
= PDE(file_inode(file
));
215 write
= pde
->proc_fops
->write
;
217 rv
= write(file
, buf
, count
, ppos
);
223 static unsigned int proc_reg_poll(struct file
*file
, struct poll_table_struct
*pts
)
225 struct proc_dir_entry
*pde
= PDE(file_inode(file
));
226 unsigned int rv
= DEFAULT_POLLMASK
;
227 unsigned int (*poll
)(struct file
*, struct poll_table_struct
*);
229 poll
= pde
->proc_fops
->poll
;
231 rv
= poll(file
, pts
);
237 static long proc_reg_unlocked_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
239 struct proc_dir_entry
*pde
= PDE(file_inode(file
));
241 long (*ioctl
)(struct file
*, unsigned int, unsigned long);
243 ioctl
= pde
->proc_fops
->unlocked_ioctl
;
245 rv
= ioctl(file
, cmd
, arg
);
252 static long proc_reg_compat_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
254 struct proc_dir_entry
*pde
= PDE(file_inode(file
));
256 long (*compat_ioctl
)(struct file
*, unsigned int, unsigned long);
258 compat_ioctl
= pde
->proc_fops
->compat_ioctl
;
260 rv
= compat_ioctl(file
, cmd
, arg
);
267 static int proc_reg_mmap(struct file
*file
, struct vm_area_struct
*vma
)
269 struct proc_dir_entry
*pde
= PDE(file_inode(file
));
271 int (*mmap
)(struct file
*, struct vm_area_struct
*);
273 mmap
= pde
->proc_fops
->mmap
;
275 rv
= mmap(file
, vma
);
282 proc_reg_get_unmapped_area(struct file
*file
, unsigned long orig_addr
,
283 unsigned long len
, unsigned long pgoff
,
286 struct proc_dir_entry
*pde
= PDE(file_inode(file
));
287 unsigned long rv
= -EIO
;
290 typeof(proc_reg_get_unmapped_area
) *get_area
;
292 get_area
= pde
->proc_fops
->get_unmapped_area
;
295 get_area
= current
->mm
->get_unmapped_area
;
299 rv
= get_area(file
, orig_addr
, len
, pgoff
, flags
);
307 static int proc_reg_open(struct inode
*inode
, struct file
*file
)
309 struct proc_dir_entry
*pde
= PDE(inode
);
311 int (*open
)(struct inode
*, struct file
*);
312 int (*release
)(struct inode
*, struct file
*);
313 struct pde_opener
*pdeo
;
316 * What for, you ask? Well, we can have open, rmmod, remove_proc_entry
317 * sequence. ->release won't be called because ->proc_fops will be
318 * cleared. Depending on complexity of ->release, consequences vary.
320 * We can't wait for mercy when close will be done for real, it's
321 * deadlockable: rmmod foo </proc/foo . So, we're going to do ->release
322 * by hand in remove_proc_entry(). For this, save opener's credentials
325 pdeo
= kzalloc(sizeof(struct pde_opener
), GFP_KERNEL
);
333 open
= pde
->proc_fops
->open
;
334 release
= pde
->proc_fops
->release
;
337 rv
= open(inode
, file
);
339 if (rv
== 0 && release
) {
340 /* To know what to release. */
342 /* Strictly for "too late" ->release in proc_reg_release(). */
343 spin_lock(&pde
->pde_unload_lock
);
344 list_add(&pdeo
->lh
, &pde
->pde_openers
);
345 spin_unlock(&pde
->pde_unload_lock
);
353 static int proc_reg_release(struct inode
*inode
, struct file
*file
)
355 struct proc_dir_entry
*pde
= PDE(inode
);
356 struct pde_opener
*pdeo
;
357 spin_lock(&pde
->pde_unload_lock
);
358 list_for_each_entry(pdeo
, &pde
->pde_openers
, lh
) {
359 if (pdeo
->file
== file
) {
360 close_pdeo(pde
, pdeo
);
364 spin_unlock(&pde
->pde_unload_lock
);
368 static const struct file_operations proc_reg_file_ops
= {
369 .llseek
= proc_reg_llseek
,
370 .read
= proc_reg_read
,
371 .write
= proc_reg_write
,
372 .poll
= proc_reg_poll
,
373 .unlocked_ioctl
= proc_reg_unlocked_ioctl
,
375 .compat_ioctl
= proc_reg_compat_ioctl
,
377 .mmap
= proc_reg_mmap
,
378 .get_unmapped_area
= proc_reg_get_unmapped_area
,
379 .open
= proc_reg_open
,
380 .release
= proc_reg_release
,
384 static const struct file_operations proc_reg_file_ops_no_compat
= {
385 .llseek
= proc_reg_llseek
,
386 .read
= proc_reg_read
,
387 .write
= proc_reg_write
,
388 .poll
= proc_reg_poll
,
389 .unlocked_ioctl
= proc_reg_unlocked_ioctl
,
390 .mmap
= proc_reg_mmap
,
391 .get_unmapped_area
= proc_reg_get_unmapped_area
,
392 .open
= proc_reg_open
,
393 .release
= proc_reg_release
,
397 static void proc_put_link(void *p
)
402 static const char *proc_get_link(struct dentry
*dentry
,
404 struct delayed_call
*done
)
406 struct proc_dir_entry
*pde
= PDE(inode
);
407 if (unlikely(!use_pde(pde
)))
408 return ERR_PTR(-EINVAL
);
409 set_delayed_call(done
, proc_put_link
, pde
);
413 const struct inode_operations proc_link_inode_operations
= {
414 .readlink
= generic_readlink
,
415 .get_link
= proc_get_link
,
418 struct inode
*proc_get_inode(struct super_block
*sb
, struct proc_dir_entry
*de
)
420 struct inode
*inode
= new_inode_pseudo(sb
);
423 inode
->i_ino
= de
->low_ino
;
424 inode
->i_mtime
= inode
->i_atime
= inode
->i_ctime
= CURRENT_TIME
;
425 PROC_I(inode
)->pde
= de
;
427 if (is_empty_pde(de
)) {
428 make_empty_dir_inode(inode
);
432 inode
->i_mode
= de
->mode
;
433 inode
->i_uid
= de
->uid
;
434 inode
->i_gid
= de
->gid
;
437 inode
->i_size
= de
->size
;
439 set_nlink(inode
, de
->nlink
);
440 WARN_ON(!de
->proc_iops
);
441 inode
->i_op
= de
->proc_iops
;
443 if (S_ISREG(inode
->i_mode
)) {
445 if (!de
->proc_fops
->compat_ioctl
)
447 &proc_reg_file_ops_no_compat
;
450 inode
->i_fop
= &proc_reg_file_ops
;
452 inode
->i_fop
= de
->proc_fops
;
460 int proc_fill_super(struct super_block
*s
, void *data
, int silent
)
462 struct pid_namespace
*ns
= get_pid_ns(s
->s_fs_info
);
463 struct inode
*root_inode
;
466 if (!proc_parse_options(data
, ns
))
469 /* User space would break if executables or devices appear on proc */
470 s
->s_iflags
|= SB_I_USERNS_VISIBLE
| SB_I_NOEXEC
| SB_I_NODEV
;
471 s
->s_flags
|= MS_NODIRATIME
| MS_NOSUID
| MS_NOEXEC
;
472 s
->s_blocksize
= 1024;
473 s
->s_blocksize_bits
= 10;
474 s
->s_magic
= PROC_SUPER_MAGIC
;
475 s
->s_op
= &proc_sops
;
479 * procfs isn't actually a stacking filesystem; however, there is
480 * too much magic going on inside it to permit stacking things on
483 s
->s_stack_depth
= FILESYSTEM_MAX_STACK_DEPTH
;
486 root_inode
= proc_get_inode(s
, &proc_root
);
488 pr_err("proc_fill_super: get root inode failed\n");
492 s
->s_root
= d_make_root(root_inode
);
494 pr_err("proc_fill_super: allocate dentry failed\n");
498 ret
= proc_setup_self(s
);
502 return proc_setup_thread_self(s
);