4 #include <linux/init.h>
5 #include <linux/sysctl.h>
6 #include <linux/poll.h>
7 #include <linux/proc_fs.h>
8 #include <linux/printk.h>
9 #include <linux/security.h>
10 #include <linux/sched.h>
11 #include <linux/cred.h>
12 #include <linux/namei.h>
14 #include <linux/module.h>
17 static const struct dentry_operations proc_sys_dentry_operations
;
18 static const struct file_operations proc_sys_file_operations
;
19 static const struct inode_operations proc_sys_inode_operations
;
20 static const struct file_operations proc_sys_dir_file_operations
;
21 static const struct inode_operations proc_sys_dir_operations
;
23 /* Support for permanently empty directories */
25 struct ctl_table sysctl_mount_point
[] = {
29 static bool is_empty_dir(struct ctl_table_header
*head
)
31 return head
->ctl_table
[0].child
== sysctl_mount_point
;
34 static void set_empty_dir(struct ctl_dir
*dir
)
36 dir
->header
.ctl_table
[0].child
= sysctl_mount_point
;
39 static void clear_empty_dir(struct ctl_dir
*dir
)
42 dir
->header
.ctl_table
[0].child
= NULL
;
45 void proc_sys_poll_notify(struct ctl_table_poll
*poll
)
50 atomic_inc(&poll
->event
);
51 wake_up_interruptible(&poll
->wait
);
54 static struct ctl_table root_table
[] = {
57 .mode
= S_IFDIR
|S_IRUGO
|S_IXUGO
,
61 static struct ctl_table_root sysctl_table_root
= {
62 .default_set
.dir
.header
= {
65 .ctl_table
= root_table
}},
66 .ctl_table_arg
= root_table
,
67 .root
= &sysctl_table_root
,
68 .set
= &sysctl_table_root
.default_set
,
72 static DEFINE_SPINLOCK(sysctl_lock
);
74 static void drop_sysctl_table(struct ctl_table_header
*header
);
75 static int sysctl_follow_link(struct ctl_table_header
**phead
,
76 struct ctl_table
**pentry
);
77 static int insert_links(struct ctl_table_header
*head
);
78 static void put_links(struct ctl_table_header
*header
);
80 static void sysctl_print_dir(struct ctl_dir
*dir
)
82 if (dir
->header
.parent
)
83 sysctl_print_dir(dir
->header
.parent
);
84 pr_cont("%s/", dir
->header
.ctl_table
[0].procname
);
87 static int namecmp(const char *name1
, int len1
, const char *name2
, int len2
)
96 cmp
= memcmp(name1
, name2
, minlen
);
102 /* Called under sysctl_lock */
103 static struct ctl_table
*find_entry(struct ctl_table_header
**phead
,
104 struct ctl_dir
*dir
, const char *name
, int namelen
)
106 struct ctl_table_header
*head
;
107 struct ctl_table
*entry
;
108 struct rb_node
*node
= dir
->root
.rb_node
;
112 struct ctl_node
*ctl_node
;
113 const char *procname
;
116 ctl_node
= rb_entry(node
, struct ctl_node
, node
);
117 head
= ctl_node
->header
;
118 entry
= &head
->ctl_table
[ctl_node
- head
->node
];
119 procname
= entry
->procname
;
121 cmp
= namecmp(name
, namelen
, procname
, strlen(procname
));
123 node
= node
->rb_left
;
125 node
= node
->rb_right
;
134 static int insert_entry(struct ctl_table_header
*head
, struct ctl_table
*entry
)
136 struct rb_node
*node
= &head
->node
[entry
- head
->ctl_table
].node
;
137 struct rb_node
**p
= &head
->parent
->root
.rb_node
;
138 struct rb_node
*parent
= NULL
;
139 const char *name
= entry
->procname
;
140 int namelen
= strlen(name
);
143 struct ctl_table_header
*parent_head
;
144 struct ctl_table
*parent_entry
;
145 struct ctl_node
*parent_node
;
146 const char *parent_name
;
150 parent_node
= rb_entry(parent
, struct ctl_node
, node
);
151 parent_head
= parent_node
->header
;
152 parent_entry
= &parent_head
->ctl_table
[parent_node
- parent_head
->node
];
153 parent_name
= parent_entry
->procname
;
155 cmp
= namecmp(name
, namelen
, parent_name
, strlen(parent_name
));
161 pr_err("sysctl duplicate entry: ");
162 sysctl_print_dir(head
->parent
);
163 pr_cont("/%s\n", entry
->procname
);
168 rb_link_node(node
, parent
, p
);
169 rb_insert_color(node
, &head
->parent
->root
);
173 static void erase_entry(struct ctl_table_header
*head
, struct ctl_table
*entry
)
175 struct rb_node
*node
= &head
->node
[entry
- head
->ctl_table
].node
;
177 rb_erase(node
, &head
->parent
->root
);
180 static void init_header(struct ctl_table_header
*head
,
181 struct ctl_table_root
*root
, struct ctl_table_set
*set
,
182 struct ctl_node
*node
, struct ctl_table
*table
)
184 head
->ctl_table
= table
;
185 head
->ctl_table_arg
= table
;
189 head
->unregistering
= NULL
;
194 INIT_LIST_HEAD(&head
->inodes
);
196 struct ctl_table
*entry
;
197 for (entry
= table
; entry
->procname
; entry
++, node
++)
202 static void erase_header(struct ctl_table_header
*head
)
204 struct ctl_table
*entry
;
205 for (entry
= head
->ctl_table
; entry
->procname
; entry
++)
206 erase_entry(head
, entry
);
209 static int insert_header(struct ctl_dir
*dir
, struct ctl_table_header
*header
)
211 struct ctl_table
*entry
;
214 /* Is this a permanently empty directory? */
215 if (is_empty_dir(&dir
->header
))
218 /* Am I creating a permanently empty directory? */
219 if (header
->ctl_table
== sysctl_mount_point
) {
220 if (!RB_EMPTY_ROOT(&dir
->root
))
226 header
->parent
= dir
;
227 err
= insert_links(header
);
230 for (entry
= header
->ctl_table
; entry
->procname
; entry
++) {
231 err
= insert_entry(header
, entry
);
237 erase_header(header
);
240 if (header
->ctl_table
== sysctl_mount_point
)
241 clear_empty_dir(dir
);
242 header
->parent
= NULL
;
243 drop_sysctl_table(&dir
->header
);
247 /* called under sysctl_lock */
248 static int use_table(struct ctl_table_header
*p
)
250 if (unlikely(p
->unregistering
))
256 /* called under sysctl_lock */
257 static void unuse_table(struct ctl_table_header
*p
)
260 if (unlikely(p
->unregistering
))
261 complete(p
->unregistering
);
264 /* called under sysctl_lock */
265 static void proc_sys_prune_dcache(struct ctl_table_header
*head
)
267 struct inode
*inode
, *prev
= NULL
;
268 struct proc_inode
*ei
;
271 list_for_each_entry_rcu(ei
, &head
->inodes
, sysctl_inodes
) {
272 inode
= igrab(&ei
->vfs_inode
);
277 d_prune_aliases(inode
);
285 /* called under sysctl_lock, will reacquire if has to wait */
286 static void start_unregistering(struct ctl_table_header
*p
)
289 * if p->used is 0, nobody will ever touch that entry again;
290 * we'll eliminate all paths to it before dropping sysctl_lock
292 if (unlikely(p
->used
)) {
293 struct completion wait
;
294 init_completion(&wait
);
295 p
->unregistering
= &wait
;
296 spin_unlock(&sysctl_lock
);
297 wait_for_completion(&wait
);
299 /* anything non-NULL; we'll never dereference it */
300 p
->unregistering
= ERR_PTR(-EINVAL
);
301 spin_unlock(&sysctl_lock
);
304 * Prune dentries for unregistered sysctls: namespaced sysctls
305 * can have duplicate names and contaminate dcache very badly.
307 proc_sys_prune_dcache(p
);
309 * do not remove from the list until nobody holds it; walking the
310 * list in do_sysctl() relies on that.
312 spin_lock(&sysctl_lock
);
316 static struct ctl_table_header
*sysctl_head_grab(struct ctl_table_header
*head
)
319 spin_lock(&sysctl_lock
);
320 if (!use_table(head
))
321 head
= ERR_PTR(-ENOENT
);
322 spin_unlock(&sysctl_lock
);
326 static void sysctl_head_finish(struct ctl_table_header
*head
)
330 spin_lock(&sysctl_lock
);
332 spin_unlock(&sysctl_lock
);
335 static struct ctl_table_set
*
336 lookup_header_set(struct ctl_table_root
*root
)
338 struct ctl_table_set
*set
= &root
->default_set
;
340 set
= root
->lookup(root
);
344 static struct ctl_table
*lookup_entry(struct ctl_table_header
**phead
,
346 const char *name
, int namelen
)
348 struct ctl_table_header
*head
;
349 struct ctl_table
*entry
;
351 spin_lock(&sysctl_lock
);
352 entry
= find_entry(&head
, dir
, name
, namelen
);
353 if (entry
&& use_table(head
))
357 spin_unlock(&sysctl_lock
);
361 static struct ctl_node
*first_usable_entry(struct rb_node
*node
)
363 struct ctl_node
*ctl_node
;
365 for (;node
; node
= rb_next(node
)) {
366 ctl_node
= rb_entry(node
, struct ctl_node
, node
);
367 if (use_table(ctl_node
->header
))
373 static void first_entry(struct ctl_dir
*dir
,
374 struct ctl_table_header
**phead
, struct ctl_table
**pentry
)
376 struct ctl_table_header
*head
= NULL
;
377 struct ctl_table
*entry
= NULL
;
378 struct ctl_node
*ctl_node
;
380 spin_lock(&sysctl_lock
);
381 ctl_node
= first_usable_entry(rb_first(&dir
->root
));
382 spin_unlock(&sysctl_lock
);
384 head
= ctl_node
->header
;
385 entry
= &head
->ctl_table
[ctl_node
- head
->node
];
391 static void next_entry(struct ctl_table_header
**phead
, struct ctl_table
**pentry
)
393 struct ctl_table_header
*head
= *phead
;
394 struct ctl_table
*entry
= *pentry
;
395 struct ctl_node
*ctl_node
= &head
->node
[entry
- head
->ctl_table
];
397 spin_lock(&sysctl_lock
);
400 ctl_node
= first_usable_entry(rb_next(&ctl_node
->node
));
401 spin_unlock(&sysctl_lock
);
404 head
= ctl_node
->header
;
405 entry
= &head
->ctl_table
[ctl_node
- head
->node
];
411 void register_sysctl_root(struct ctl_table_root
*root
)
416 * sysctl_perm does NOT grant the superuser all rights automatically, because
417 * some sysctl variables are readonly even to root.
420 static int test_perm(int mode
, int op
)
422 if (uid_eq(current_euid(), GLOBAL_ROOT_UID
))
424 else if (in_egroup_p(GLOBAL_ROOT_GID
))
426 if ((op
& ~mode
& (MAY_READ
|MAY_WRITE
|MAY_EXEC
)) == 0)
431 static int sysctl_perm(struct ctl_table_header
*head
, struct ctl_table
*table
, int op
)
433 struct ctl_table_root
*root
= head
->root
;
436 if (root
->permissions
)
437 mode
= root
->permissions(head
, table
);
441 return test_perm(mode
, op
);
444 static struct inode
*proc_sys_make_inode(struct super_block
*sb
,
445 struct ctl_table_header
*head
, struct ctl_table
*table
)
447 struct ctl_table_root
*root
= head
->root
;
449 struct proc_inode
*ei
;
451 inode
= new_inode(sb
);
455 inode
->i_ino
= get_next_ino();
459 spin_lock(&sysctl_lock
);
460 if (unlikely(head
->unregistering
)) {
461 spin_unlock(&sysctl_lock
);
467 ei
->sysctl_entry
= table
;
468 list_add_rcu(&ei
->sysctl_inodes
, &head
->inodes
);
470 spin_unlock(&sysctl_lock
);
472 inode
->i_mtime
= inode
->i_atime
= inode
->i_ctime
= current_time(inode
);
473 inode
->i_mode
= table
->mode
;
474 if (!S_ISDIR(table
->mode
)) {
475 inode
->i_mode
|= S_IFREG
;
476 inode
->i_op
= &proc_sys_inode_operations
;
477 inode
->i_fop
= &proc_sys_file_operations
;
479 inode
->i_mode
|= S_IFDIR
;
480 inode
->i_op
= &proc_sys_dir_operations
;
481 inode
->i_fop
= &proc_sys_dir_file_operations
;
482 if (is_empty_dir(head
))
483 make_empty_dir_inode(inode
);
486 if (root
->set_ownership
)
487 root
->set_ownership(head
, table
, &inode
->i_uid
, &inode
->i_gid
);
493 void proc_sys_evict_inode(struct inode
*inode
, struct ctl_table_header
*head
)
495 spin_lock(&sysctl_lock
);
496 list_del_rcu(&PROC_I(inode
)->sysctl_inodes
);
498 kfree_rcu(head
, rcu
);
499 spin_unlock(&sysctl_lock
);
502 static struct ctl_table_header
*grab_header(struct inode
*inode
)
504 struct ctl_table_header
*head
= PROC_I(inode
)->sysctl
;
506 head
= &sysctl_table_root
.default_set
.dir
.header
;
507 return sysctl_head_grab(head
);
510 static struct dentry
*proc_sys_lookup(struct inode
*dir
, struct dentry
*dentry
,
513 struct ctl_table_header
*head
= grab_header(dir
);
514 struct ctl_table_header
*h
= NULL
;
515 const struct qstr
*name
= &dentry
->d_name
;
518 struct dentry
*err
= ERR_PTR(-ENOENT
);
519 struct ctl_dir
*ctl_dir
;
523 return ERR_CAST(head
);
525 ctl_dir
= container_of(head
, struct ctl_dir
, header
);
527 p
= lookup_entry(&h
, ctl_dir
, name
->name
, name
->len
);
531 if (S_ISLNK(p
->mode
)) {
532 ret
= sysctl_follow_link(&h
, &p
);
538 err
= ERR_PTR(-ENOMEM
);
539 inode
= proc_sys_make_inode(dir
->i_sb
, h
? h
: head
, p
);
544 d_set_d_op(dentry
, &proc_sys_dentry_operations
);
545 d_add(dentry
, inode
);
549 sysctl_head_finish(h
);
550 sysctl_head_finish(head
);
554 static ssize_t
proc_sys_call_handler(struct file
*filp
, void __user
*buf
,
555 size_t count
, loff_t
*ppos
, int write
)
557 struct inode
*inode
= file_inode(filp
);
558 struct ctl_table_header
*head
= grab_header(inode
);
559 struct ctl_table
*table
= PROC_I(inode
)->sysctl_entry
;
564 return PTR_ERR(head
);
567 * At this point we know that the sysctl was not unregistered
568 * and won't be until we finish.
571 if (sysctl_perm(head
, table
, write
? MAY_WRITE
: MAY_READ
))
574 /* if that can happen at all, it should be -EINVAL, not -EISDIR */
576 if (!table
->proc_handler
)
579 /* careful: calling conventions are nasty here */
581 error
= table
->proc_handler(table
, write
, buf
, &res
, ppos
);
585 sysctl_head_finish(head
);
590 static ssize_t
proc_sys_read(struct file
*filp
, char __user
*buf
,
591 size_t count
, loff_t
*ppos
)
593 return proc_sys_call_handler(filp
, (void __user
*)buf
, count
, ppos
, 0);
596 static ssize_t
proc_sys_write(struct file
*filp
, const char __user
*buf
,
597 size_t count
, loff_t
*ppos
)
599 return proc_sys_call_handler(filp
, (void __user
*)buf
, count
, ppos
, 1);
602 static int proc_sys_open(struct inode
*inode
, struct file
*filp
)
604 struct ctl_table_header
*head
= grab_header(inode
);
605 struct ctl_table
*table
= PROC_I(inode
)->sysctl_entry
;
607 /* sysctl was unregistered */
609 return PTR_ERR(head
);
612 filp
->private_data
= proc_sys_poll_event(table
->poll
);
614 sysctl_head_finish(head
);
619 static unsigned int proc_sys_poll(struct file
*filp
, poll_table
*wait
)
621 struct inode
*inode
= file_inode(filp
);
622 struct ctl_table_header
*head
= grab_header(inode
);
623 struct ctl_table
*table
= PROC_I(inode
)->sysctl_entry
;
624 unsigned int ret
= DEFAULT_POLLMASK
;
627 /* sysctl was unregistered */
629 return POLLERR
| POLLHUP
;
631 if (!table
->proc_handler
)
637 event
= (unsigned long)filp
->private_data
;
638 poll_wait(filp
, &table
->poll
->wait
, wait
);
640 if (event
!= atomic_read(&table
->poll
->event
)) {
641 filp
->private_data
= proc_sys_poll_event(table
->poll
);
642 ret
= POLLIN
| POLLRDNORM
| POLLERR
| POLLPRI
;
646 sysctl_head_finish(head
);
651 static bool proc_sys_fill_cache(struct file
*file
,
652 struct dir_context
*ctx
,
653 struct ctl_table_header
*head
,
654 struct ctl_table
*table
)
656 struct dentry
*child
, *dir
= file
->f_path
.dentry
;
660 unsigned type
= DT_UNKNOWN
;
662 qname
.name
= table
->procname
;
663 qname
.len
= strlen(table
->procname
);
664 qname
.hash
= full_name_hash(dir
, qname
.name
, qname
.len
);
666 child
= d_lookup(dir
, &qname
);
668 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq
);
669 child
= d_alloc_parallel(dir
, &qname
, &wq
);
672 if (d_in_lookup(child
)) {
673 inode
= proc_sys_make_inode(dir
->d_sb
, head
, table
);
675 d_lookup_done(child
);
679 d_set_d_op(child
, &proc_sys_dentry_operations
);
683 inode
= d_inode(child
);
685 type
= inode
->i_mode
>> 12;
687 return dir_emit(ctx
, qname
.name
, qname
.len
, ino
, type
);
690 static bool proc_sys_link_fill_cache(struct file
*file
,
691 struct dir_context
*ctx
,
692 struct ctl_table_header
*head
,
693 struct ctl_table
*table
)
696 head
= sysctl_head_grab(head
);
698 if (S_ISLNK(table
->mode
)) {
699 /* It is not an error if we can not follow the link ignore it */
700 int err
= sysctl_follow_link(&head
, &table
);
705 ret
= proc_sys_fill_cache(file
, ctx
, head
, table
);
707 sysctl_head_finish(head
);
711 static int scan(struct ctl_table_header
*head
, struct ctl_table
*table
,
712 unsigned long *pos
, struct file
*file
,
713 struct dir_context
*ctx
)
717 if ((*pos
)++ < ctx
->pos
)
720 if (unlikely(S_ISLNK(table
->mode
)))
721 res
= proc_sys_link_fill_cache(file
, ctx
, head
, table
);
723 res
= proc_sys_fill_cache(file
, ctx
, head
, table
);
731 static int proc_sys_readdir(struct file
*file
, struct dir_context
*ctx
)
733 struct ctl_table_header
*head
= grab_header(file_inode(file
));
734 struct ctl_table_header
*h
= NULL
;
735 struct ctl_table
*entry
;
736 struct ctl_dir
*ctl_dir
;
740 return PTR_ERR(head
);
742 ctl_dir
= container_of(head
, struct ctl_dir
, header
);
744 if (!dir_emit_dots(file
, ctx
))
749 for (first_entry(ctl_dir
, &h
, &entry
); h
; next_entry(&h
, &entry
)) {
750 if (!scan(h
, entry
, &pos
, file
, ctx
)) {
751 sysctl_head_finish(h
);
756 sysctl_head_finish(head
);
760 static int proc_sys_permission(struct inode
*inode
, int mask
)
763 * sysctl entries that are not writeable,
764 * are _NOT_ writeable, capabilities or not.
766 struct ctl_table_header
*head
;
767 struct ctl_table
*table
;
770 /* Executable files are not allowed under /proc/sys/ */
771 if ((mask
& MAY_EXEC
) && S_ISREG(inode
->i_mode
))
774 head
= grab_header(inode
);
776 return PTR_ERR(head
);
778 table
= PROC_I(inode
)->sysctl_entry
;
779 if (!table
) /* global root - r-xr-xr-x */
780 error
= mask
& MAY_WRITE
? -EACCES
: 0;
781 else /* Use the permissions on the sysctl table entry */
782 error
= sysctl_perm(head
, table
, mask
& ~MAY_NOT_BLOCK
);
784 sysctl_head_finish(head
);
788 static int proc_sys_setattr(struct dentry
*dentry
, struct iattr
*attr
)
790 struct inode
*inode
= d_inode(dentry
);
793 if (attr
->ia_valid
& (ATTR_MODE
| ATTR_UID
| ATTR_GID
))
796 error
= setattr_prepare(dentry
, attr
);
800 setattr_copy(inode
, attr
);
801 mark_inode_dirty(inode
);
805 static int proc_sys_getattr(const struct path
*path
, struct kstat
*stat
,
806 u32 request_mask
, unsigned int query_flags
)
808 struct inode
*inode
= d_inode(path
->dentry
);
809 struct ctl_table_header
*head
= grab_header(inode
);
810 struct ctl_table
*table
= PROC_I(inode
)->sysctl_entry
;
813 return PTR_ERR(head
);
815 generic_fillattr(inode
, stat
);
817 stat
->mode
= (stat
->mode
& S_IFMT
) | table
->mode
;
819 sysctl_head_finish(head
);
823 static const struct file_operations proc_sys_file_operations
= {
824 .open
= proc_sys_open
,
825 .poll
= proc_sys_poll
,
826 .read
= proc_sys_read
,
827 .write
= proc_sys_write
,
828 .llseek
= default_llseek
,
831 static const struct file_operations proc_sys_dir_file_operations
= {
832 .read
= generic_read_dir
,
833 .iterate_shared
= proc_sys_readdir
,
834 .llseek
= generic_file_llseek
,
837 static const struct inode_operations proc_sys_inode_operations
= {
838 .permission
= proc_sys_permission
,
839 .setattr
= proc_sys_setattr
,
840 .getattr
= proc_sys_getattr
,
843 static const struct inode_operations proc_sys_dir_operations
= {
844 .lookup
= proc_sys_lookup
,
845 .permission
= proc_sys_permission
,
846 .setattr
= proc_sys_setattr
,
847 .getattr
= proc_sys_getattr
,
850 static int proc_sys_revalidate(struct dentry
*dentry
, unsigned int flags
)
852 if (flags
& LOOKUP_RCU
)
854 return !PROC_I(d_inode(dentry
))->sysctl
->unregistering
;
857 static int proc_sys_delete(const struct dentry
*dentry
)
859 return !!PROC_I(d_inode(dentry
))->sysctl
->unregistering
;
862 static int sysctl_is_seen(struct ctl_table_header
*p
)
864 struct ctl_table_set
*set
= p
->set
;
866 spin_lock(&sysctl_lock
);
867 if (p
->unregistering
)
869 else if (!set
->is_seen
)
872 res
= set
->is_seen(set
);
873 spin_unlock(&sysctl_lock
);
877 static int proc_sys_compare(const struct dentry
*dentry
,
878 unsigned int len
, const char *str
, const struct qstr
*name
)
880 struct ctl_table_header
*head
;
883 /* Although proc doesn't have negative dentries, rcu-walk means
884 * that inode here can be NULL */
885 /* AV: can it, indeed? */
886 inode
= d_inode_rcu(dentry
);
889 if (name
->len
!= len
)
891 if (memcmp(name
->name
, str
, len
))
893 head
= rcu_dereference(PROC_I(inode
)->sysctl
);
894 return !head
|| !sysctl_is_seen(head
);
897 static const struct dentry_operations proc_sys_dentry_operations
= {
898 .d_revalidate
= proc_sys_revalidate
,
899 .d_delete
= proc_sys_delete
,
900 .d_compare
= proc_sys_compare
,
903 static struct ctl_dir
*find_subdir(struct ctl_dir
*dir
,
904 const char *name
, int namelen
)
906 struct ctl_table_header
*head
;
907 struct ctl_table
*entry
;
909 entry
= find_entry(&head
, dir
, name
, namelen
);
911 return ERR_PTR(-ENOENT
);
912 if (!S_ISDIR(entry
->mode
))
913 return ERR_PTR(-ENOTDIR
);
914 return container_of(head
, struct ctl_dir
, header
);
917 static struct ctl_dir
*new_dir(struct ctl_table_set
*set
,
918 const char *name
, int namelen
)
920 struct ctl_table
*table
;
922 struct ctl_node
*node
;
925 new = kzalloc(sizeof(*new) + sizeof(struct ctl_node
) +
926 sizeof(struct ctl_table
)*2 + namelen
+ 1,
931 node
= (struct ctl_node
*)(new + 1);
932 table
= (struct ctl_table
*)(node
+ 1);
933 new_name
= (char *)(table
+ 2);
934 memcpy(new_name
, name
, namelen
);
935 new_name
[namelen
] = '\0';
936 table
[0].procname
= new_name
;
937 table
[0].mode
= S_IFDIR
|S_IRUGO
|S_IXUGO
;
938 init_header(&new->header
, set
->dir
.header
.root
, set
, node
, table
);
944 * get_subdir - find or create a subdir with the specified name.
945 * @dir: Directory to create the subdirectory in
946 * @name: The name of the subdirectory to find or create
947 * @namelen: The length of name
949 * Takes a directory with an elevated reference count so we know that
950 * if we drop the lock the directory will not go away. Upon success
951 * the reference is moved from @dir to the returned subdirectory.
952 * Upon error an error code is returned and the reference on @dir is
955 static struct ctl_dir
*get_subdir(struct ctl_dir
*dir
,
956 const char *name
, int namelen
)
958 struct ctl_table_set
*set
= dir
->header
.set
;
959 struct ctl_dir
*subdir
, *new = NULL
;
962 spin_lock(&sysctl_lock
);
963 subdir
= find_subdir(dir
, name
, namelen
);
966 if (PTR_ERR(subdir
) != -ENOENT
)
969 spin_unlock(&sysctl_lock
);
970 new = new_dir(set
, name
, namelen
);
971 spin_lock(&sysctl_lock
);
972 subdir
= ERR_PTR(-ENOMEM
);
976 /* Was the subdir added while we dropped the lock? */
977 subdir
= find_subdir(dir
, name
, namelen
);
980 if (PTR_ERR(subdir
) != -ENOENT
)
983 /* Nope. Use the our freshly made directory entry. */
984 err
= insert_header(dir
, &new->header
);
985 subdir
= ERR_PTR(err
);
990 subdir
->header
.nreg
++;
992 if (IS_ERR(subdir
)) {
993 pr_err("sysctl could not get directory: ");
994 sysctl_print_dir(dir
);
995 pr_cont("/%*.*s %ld\n",
996 namelen
, namelen
, name
, PTR_ERR(subdir
));
998 drop_sysctl_table(&dir
->header
);
1000 drop_sysctl_table(&new->header
);
1001 spin_unlock(&sysctl_lock
);
1005 static struct ctl_dir
*xlate_dir(struct ctl_table_set
*set
, struct ctl_dir
*dir
)
1007 struct ctl_dir
*parent
;
1008 const char *procname
;
1009 if (!dir
->header
.parent
)
1011 parent
= xlate_dir(set
, dir
->header
.parent
);
1014 procname
= dir
->header
.ctl_table
[0].procname
;
1015 return find_subdir(parent
, procname
, strlen(procname
));
1018 static int sysctl_follow_link(struct ctl_table_header
**phead
,
1019 struct ctl_table
**pentry
)
1021 struct ctl_table_header
*head
;
1022 struct ctl_table_root
*root
;
1023 struct ctl_table_set
*set
;
1024 struct ctl_table
*entry
;
1025 struct ctl_dir
*dir
;
1029 spin_lock(&sysctl_lock
);
1030 root
= (*pentry
)->data
;
1031 set
= lookup_header_set(root
);
1032 dir
= xlate_dir(set
, (*phead
)->parent
);
1036 const char *procname
= (*pentry
)->procname
;
1038 entry
= find_entry(&head
, dir
, procname
, strlen(procname
));
1040 if (entry
&& use_table(head
)) {
1041 unuse_table(*phead
);
1048 spin_unlock(&sysctl_lock
);
1052 static int sysctl_err(const char *path
, struct ctl_table
*table
, char *fmt
, ...)
1054 struct va_format vaf
;
1057 va_start(args
, fmt
);
1061 pr_err("sysctl table check failed: %s/%s %pV\n",
1062 path
, table
->procname
, &vaf
);
1068 static int sysctl_check_table(const char *path
, struct ctl_table
*table
)
1071 for (; table
->procname
; table
++) {
1073 err
= sysctl_err(path
, table
, "Not a file");
1075 if ((table
->proc_handler
== proc_dostring
) ||
1076 (table
->proc_handler
== proc_dointvec
) ||
1077 (table
->proc_handler
== proc_dointvec_minmax
) ||
1078 (table
->proc_handler
== proc_dointvec_jiffies
) ||
1079 (table
->proc_handler
== proc_dointvec_userhz_jiffies
) ||
1080 (table
->proc_handler
== proc_dointvec_ms_jiffies
) ||
1081 (table
->proc_handler
== proc_doulongvec_minmax
) ||
1082 (table
->proc_handler
== proc_doulongvec_ms_jiffies_minmax
)) {
1084 err
= sysctl_err(path
, table
, "No data");
1086 err
= sysctl_err(path
, table
, "No maxlen");
1088 if (!table
->proc_handler
)
1089 err
= sysctl_err(path
, table
, "No proc_handler");
1091 if ((table
->mode
& (S_IRUGO
|S_IWUGO
)) != table
->mode
)
1092 err
= sysctl_err(path
, table
, "bogus .mode 0%o",
1098 static struct ctl_table_header
*new_links(struct ctl_dir
*dir
, struct ctl_table
*table
,
1099 struct ctl_table_root
*link_root
)
1101 struct ctl_table
*link_table
, *entry
, *link
;
1102 struct ctl_table_header
*links
;
1103 struct ctl_node
*node
;
1105 int nr_entries
, name_bytes
;
1109 for (entry
= table
; entry
->procname
; entry
++) {
1111 name_bytes
+= strlen(entry
->procname
) + 1;
1114 links
= kzalloc(sizeof(struct ctl_table_header
) +
1115 sizeof(struct ctl_node
)*nr_entries
+
1116 sizeof(struct ctl_table
)*(nr_entries
+ 1) +
1123 node
= (struct ctl_node
*)(links
+ 1);
1124 link_table
= (struct ctl_table
*)(node
+ nr_entries
);
1125 link_name
= (char *)&link_table
[nr_entries
+ 1];
1127 for (link
= link_table
, entry
= table
; entry
->procname
; link
++, entry
++) {
1128 int len
= strlen(entry
->procname
) + 1;
1129 memcpy(link_name
, entry
->procname
, len
);
1130 link
->procname
= link_name
;
1131 link
->mode
= S_IFLNK
|S_IRWXUGO
;
1132 link
->data
= link_root
;
1135 init_header(links
, dir
->header
.root
, dir
->header
.set
, node
, link_table
);
1136 links
->nreg
= nr_entries
;
1141 static bool get_links(struct ctl_dir
*dir
,
1142 struct ctl_table
*table
, struct ctl_table_root
*link_root
)
1144 struct ctl_table_header
*head
;
1145 struct ctl_table
*entry
, *link
;
1147 /* Are there links available for every entry in table? */
1148 for (entry
= table
; entry
->procname
; entry
++) {
1149 const char *procname
= entry
->procname
;
1150 link
= find_entry(&head
, dir
, procname
, strlen(procname
));
1153 if (S_ISDIR(link
->mode
) && S_ISDIR(entry
->mode
))
1155 if (S_ISLNK(link
->mode
) && (link
->data
== link_root
))
1160 /* The checks passed. Increase the registration count on the links */
1161 for (entry
= table
; entry
->procname
; entry
++) {
1162 const char *procname
= entry
->procname
;
1163 link
= find_entry(&head
, dir
, procname
, strlen(procname
));
1169 static int insert_links(struct ctl_table_header
*head
)
1171 struct ctl_table_set
*root_set
= &sysctl_table_root
.default_set
;
1172 struct ctl_dir
*core_parent
= NULL
;
1173 struct ctl_table_header
*links
;
1176 if (head
->set
== root_set
)
1179 core_parent
= xlate_dir(root_set
, head
->parent
);
1180 if (IS_ERR(core_parent
))
1183 if (get_links(core_parent
, head
->ctl_table
, head
->root
))
1186 core_parent
->header
.nreg
++;
1187 spin_unlock(&sysctl_lock
);
1189 links
= new_links(core_parent
, head
->ctl_table
, head
->root
);
1191 spin_lock(&sysctl_lock
);
1197 if (get_links(core_parent
, head
->ctl_table
, head
->root
)) {
1202 err
= insert_header(core_parent
, links
);
1206 drop_sysctl_table(&core_parent
->header
);
1211 * __register_sysctl_table - register a leaf sysctl table
1212 * @set: Sysctl tree to register on
1213 * @path: The path to the directory the sysctl table is in.
1214 * @table: the top-level table structure
1216 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1217 * array. A completely 0 filled entry terminates the table.
1219 * The members of the &struct ctl_table structure are used as follows:
1221 * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
1222 * enter a sysctl file
1224 * data - a pointer to data for use by proc_handler
1226 * maxlen - the maximum size in bytes of the data
1228 * mode - the file permissions for the /proc/sys file
1230 * child - must be %NULL.
1232 * proc_handler - the text handler routine (described below)
1234 * extra1, extra2 - extra pointers usable by the proc handler routines
1236 * Leaf nodes in the sysctl tree will be represented by a single file
1237 * under /proc; non-leaf nodes will be represented by directories.
1239 * There must be a proc_handler routine for any terminal nodes.
1240 * Several default handlers are available to cover common cases -
1242 * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
1243 * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
1244 * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
1246 * It is the handler's job to read the input buffer from user memory
1247 * and process it. The handler should return 0 on success.
1249 * This routine returns %NULL on a failure to register, and a pointer
1250 * to the table header on success.
1252 struct ctl_table_header
*__register_sysctl_table(
1253 struct ctl_table_set
*set
,
1254 const char *path
, struct ctl_table
*table
)
1256 struct ctl_table_root
*root
= set
->dir
.header
.root
;
1257 struct ctl_table_header
*header
;
1258 const char *name
, *nextname
;
1259 struct ctl_dir
*dir
;
1260 struct ctl_table
*entry
;
1261 struct ctl_node
*node
;
1264 for (entry
= table
; entry
->procname
; entry
++)
1267 header
= kzalloc(sizeof(struct ctl_table_header
) +
1268 sizeof(struct ctl_node
)*nr_entries
, GFP_KERNEL
);
1272 node
= (struct ctl_node
*)(header
+ 1);
1273 init_header(header
, root
, set
, node
, table
);
1274 if (sysctl_check_table(path
, table
))
1277 spin_lock(&sysctl_lock
);
1279 /* Reference moved down the diretory tree get_subdir */
1281 spin_unlock(&sysctl_lock
);
1283 /* Find the directory for the ctl_table */
1284 for (name
= path
; name
; name
= nextname
) {
1286 nextname
= strchr(name
, '/');
1288 namelen
= nextname
- name
;
1291 namelen
= strlen(name
);
1296 dir
= get_subdir(dir
, name
, namelen
);
1301 spin_lock(&sysctl_lock
);
1302 if (insert_header(dir
, header
))
1303 goto fail_put_dir_locked
;
1305 drop_sysctl_table(&dir
->header
);
1306 spin_unlock(&sysctl_lock
);
1310 fail_put_dir_locked
:
1311 drop_sysctl_table(&dir
->header
);
1312 spin_unlock(&sysctl_lock
);
1320 * register_sysctl - register a sysctl table
1321 * @path: The path to the directory the sysctl table is in.
1322 * @table: the table structure
1324 * Register a sysctl table. @table should be a filled in ctl_table
1325 * array. A completely 0 filled entry terminates the table.
1327 * See __register_sysctl_table for more details.
1329 struct ctl_table_header
*register_sysctl(const char *path
, struct ctl_table
*table
)
1331 return __register_sysctl_table(&sysctl_table_root
.default_set
,
1334 EXPORT_SYMBOL(register_sysctl
);
1336 static char *append_path(const char *path
, char *pos
, const char *name
)
1339 namelen
= strlen(name
);
1340 if (((pos
- path
) + namelen
+ 2) >= PATH_MAX
)
1342 memcpy(pos
, name
, namelen
);
1344 pos
[namelen
+ 1] = '\0';
1349 static int count_subheaders(struct ctl_table
*table
)
1352 int nr_subheaders
= 0;
1353 struct ctl_table
*entry
;
1355 /* special case: no directory and empty directory */
1356 if (!table
|| !table
->procname
)
1359 for (entry
= table
; entry
->procname
; entry
++) {
1361 nr_subheaders
+= count_subheaders(entry
->child
);
1365 return nr_subheaders
+ has_files
;
1368 static int register_leaf_sysctl_tables(const char *path
, char *pos
,
1369 struct ctl_table_header
***subheader
, struct ctl_table_set
*set
,
1370 struct ctl_table
*table
)
1372 struct ctl_table
*ctl_table_arg
= NULL
;
1373 struct ctl_table
*entry
, *files
;
1378 for (entry
= table
; entry
->procname
; entry
++) {
1386 /* If there are mixed files and directories we need a new table */
1387 if (nr_dirs
&& nr_files
) {
1388 struct ctl_table
*new;
1389 files
= kzalloc(sizeof(struct ctl_table
) * (nr_files
+ 1),
1394 ctl_table_arg
= files
;
1395 for (new = files
, entry
= table
; entry
->procname
; entry
++) {
1403 /* Register everything except a directory full of subdirectories */
1404 if (nr_files
|| !nr_dirs
) {
1405 struct ctl_table_header
*header
;
1406 header
= __register_sysctl_table(set
, path
, files
);
1408 kfree(ctl_table_arg
);
1412 /* Remember if we need to free the file table */
1413 header
->ctl_table_arg
= ctl_table_arg
;
1414 **subheader
= header
;
1418 /* Recurse into the subdirectories. */
1419 for (entry
= table
; entry
->procname
; entry
++) {
1425 err
= -ENAMETOOLONG
;
1426 child_pos
= append_path(path
, pos
, entry
->procname
);
1430 err
= register_leaf_sysctl_tables(path
, child_pos
, subheader
,
1438 /* On failure our caller will unregister all registered subheaders */
1443 * __register_sysctl_paths - register a sysctl table hierarchy
1444 * @set: Sysctl tree to register on
1445 * @path: The path to the directory the sysctl table is in.
1446 * @table: the top-level table structure
1448 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1449 * array. A completely 0 filled entry terminates the table.
1451 * See __register_sysctl_table for more details.
1453 struct ctl_table_header
*__register_sysctl_paths(
1454 struct ctl_table_set
*set
,
1455 const struct ctl_path
*path
, struct ctl_table
*table
)
1457 struct ctl_table
*ctl_table_arg
= table
;
1458 int nr_subheaders
= count_subheaders(table
);
1459 struct ctl_table_header
*header
= NULL
, **subheaders
, **subheader
;
1460 const struct ctl_path
*component
;
1461 char *new_path
, *pos
;
1463 pos
= new_path
= kmalloc(PATH_MAX
, GFP_KERNEL
);
1468 for (component
= path
; component
->procname
; component
++) {
1469 pos
= append_path(new_path
, pos
, component
->procname
);
1473 while (table
->procname
&& table
->child
&& !table
[1].procname
) {
1474 pos
= append_path(new_path
, pos
, table
->procname
);
1477 table
= table
->child
;
1479 if (nr_subheaders
== 1) {
1480 header
= __register_sysctl_table(set
, new_path
, table
);
1482 header
->ctl_table_arg
= ctl_table_arg
;
1484 header
= kzalloc(sizeof(*header
) +
1485 sizeof(*subheaders
)*nr_subheaders
, GFP_KERNEL
);
1489 subheaders
= (struct ctl_table_header
**) (header
+ 1);
1490 subheader
= subheaders
;
1491 header
->ctl_table_arg
= ctl_table_arg
;
1493 if (register_leaf_sysctl_tables(new_path
, pos
, &subheader
,
1495 goto err_register_leaves
;
1502 err_register_leaves
:
1503 while (subheader
> subheaders
) {
1504 struct ctl_table_header
*subh
= *(--subheader
);
1505 struct ctl_table
*table
= subh
->ctl_table_arg
;
1506 unregister_sysctl_table(subh
);
1515 * register_sysctl_table_path - register a sysctl table hierarchy
1516 * @path: The path to the directory the sysctl table is in.
1517 * @table: the top-level table structure
1519 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1520 * array. A completely 0 filled entry terminates the table.
1522 * See __register_sysctl_paths for more details.
1524 struct ctl_table_header
*register_sysctl_paths(const struct ctl_path
*path
,
1525 struct ctl_table
*table
)
1527 return __register_sysctl_paths(&sysctl_table_root
.default_set
,
1530 EXPORT_SYMBOL(register_sysctl_paths
);
1533 * register_sysctl_table - register a sysctl table hierarchy
1534 * @table: the top-level table structure
1536 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1537 * array. A completely 0 filled entry terminates the table.
1539 * See register_sysctl_paths for more details.
1541 struct ctl_table_header
*register_sysctl_table(struct ctl_table
*table
)
1543 static const struct ctl_path null_path
[] = { {} };
1545 return register_sysctl_paths(null_path
, table
);
1547 EXPORT_SYMBOL(register_sysctl_table
);
1549 static void put_links(struct ctl_table_header
*header
)
1551 struct ctl_table_set
*root_set
= &sysctl_table_root
.default_set
;
1552 struct ctl_table_root
*root
= header
->root
;
1553 struct ctl_dir
*parent
= header
->parent
;
1554 struct ctl_dir
*core_parent
;
1555 struct ctl_table
*entry
;
1557 if (header
->set
== root_set
)
1560 core_parent
= xlate_dir(root_set
, parent
);
1561 if (IS_ERR(core_parent
))
1564 for (entry
= header
->ctl_table
; entry
->procname
; entry
++) {
1565 struct ctl_table_header
*link_head
;
1566 struct ctl_table
*link
;
1567 const char *name
= entry
->procname
;
1569 link
= find_entry(&link_head
, core_parent
, name
, strlen(name
));
1571 ((S_ISDIR(link
->mode
) && S_ISDIR(entry
->mode
)) ||
1572 (S_ISLNK(link
->mode
) && (link
->data
== root
)))) {
1573 drop_sysctl_table(link_head
);
1576 pr_err("sysctl link missing during unregister: ");
1577 sysctl_print_dir(parent
);
1578 pr_cont("/%s\n", name
);
1583 static void drop_sysctl_table(struct ctl_table_header
*header
)
1585 struct ctl_dir
*parent
= header
->parent
;
1591 start_unregistering(header
);
1592 if (!--header
->count
)
1593 kfree_rcu(header
, rcu
);
1596 drop_sysctl_table(&parent
->header
);
1600 * unregister_sysctl_table - unregister a sysctl table hierarchy
1601 * @header: the header returned from register_sysctl_table
1603 * Unregisters the sysctl table and all children. proc entries may not
1604 * actually be removed until they are no longer used by anyone.
1606 void unregister_sysctl_table(struct ctl_table_header
* header
)
1614 nr_subheaders
= count_subheaders(header
->ctl_table_arg
);
1615 if (unlikely(nr_subheaders
> 1)) {
1616 struct ctl_table_header
**subheaders
;
1619 subheaders
= (struct ctl_table_header
**)(header
+ 1);
1620 for (i
= nr_subheaders
-1; i
>= 0; i
--) {
1621 struct ctl_table_header
*subh
= subheaders
[i
];
1622 struct ctl_table
*table
= subh
->ctl_table_arg
;
1623 unregister_sysctl_table(subh
);
1630 spin_lock(&sysctl_lock
);
1631 drop_sysctl_table(header
);
1632 spin_unlock(&sysctl_lock
);
1634 EXPORT_SYMBOL(unregister_sysctl_table
);
1636 void setup_sysctl_set(struct ctl_table_set
*set
,
1637 struct ctl_table_root
*root
,
1638 int (*is_seen
)(struct ctl_table_set
*))
1640 memset(set
, 0, sizeof(*set
));
1641 set
->is_seen
= is_seen
;
1642 init_header(&set
->dir
.header
, root
, set
, NULL
, root_table
);
1645 void retire_sysctl_set(struct ctl_table_set
*set
)
1647 WARN_ON(!RB_EMPTY_ROOT(&set
->dir
.root
));
1650 int __init
proc_sys_init(void)
1652 struct proc_dir_entry
*proc_sys_root
;
1654 proc_sys_root
= proc_mkdir("sys", NULL
);
1655 proc_sys_root
->proc_iops
= &proc_sys_dir_operations
;
1656 proc_sys_root
->proc_fops
= &proc_sys_dir_file_operations
;
1657 proc_sys_root
->nlink
= 0;
1659 return sysctl_init();