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/namei.h>
13 #include <linux/module.h>
16 static const struct dentry_operations proc_sys_dentry_operations
;
17 static const struct file_operations proc_sys_file_operations
;
18 static const struct inode_operations proc_sys_inode_operations
;
19 static const struct file_operations proc_sys_dir_file_operations
;
20 static const struct inode_operations proc_sys_dir_operations
;
22 /* Support for permanently empty directories */
24 struct ctl_table sysctl_mount_point
[] = {
28 static bool is_empty_dir(struct ctl_table_header
*head
)
30 return head
->ctl_table
[0].child
== sysctl_mount_point
;
33 static void set_empty_dir(struct ctl_dir
*dir
)
35 dir
->header
.ctl_table
[0].child
= sysctl_mount_point
;
38 static void clear_empty_dir(struct ctl_dir
*dir
)
41 dir
->header
.ctl_table
[0].child
= NULL
;
44 void proc_sys_poll_notify(struct ctl_table_poll
*poll
)
49 atomic_inc(&poll
->event
);
50 wake_up_interruptible(&poll
->wait
);
53 static struct ctl_table root_table
[] = {
56 .mode
= S_IFDIR
|S_IRUGO
|S_IXUGO
,
60 static struct ctl_table_root sysctl_table_root
= {
61 .default_set
.dir
.header
= {
64 .ctl_table
= root_table
}},
65 .ctl_table_arg
= root_table
,
66 .root
= &sysctl_table_root
,
67 .set
= &sysctl_table_root
.default_set
,
71 static DEFINE_SPINLOCK(sysctl_lock
);
73 static void drop_sysctl_table(struct ctl_table_header
*header
);
74 static int sysctl_follow_link(struct ctl_table_header
**phead
,
75 struct ctl_table
**pentry
);
76 static int insert_links(struct ctl_table_header
*head
);
77 static void put_links(struct ctl_table_header
*header
);
79 static void sysctl_print_dir(struct ctl_dir
*dir
)
81 if (dir
->header
.parent
)
82 sysctl_print_dir(dir
->header
.parent
);
83 pr_cont("%s/", dir
->header
.ctl_table
[0].procname
);
86 static int namecmp(const char *name1
, int len1
, const char *name2
, int len2
)
95 cmp
= memcmp(name1
, name2
, minlen
);
101 /* Called under sysctl_lock */
102 static struct ctl_table
*find_entry(struct ctl_table_header
**phead
,
103 struct ctl_dir
*dir
, const char *name
, int namelen
)
105 struct ctl_table_header
*head
;
106 struct ctl_table
*entry
;
107 struct rb_node
*node
= dir
->root
.rb_node
;
111 struct ctl_node
*ctl_node
;
112 const char *procname
;
115 ctl_node
= rb_entry(node
, struct ctl_node
, node
);
116 head
= ctl_node
->header
;
117 entry
= &head
->ctl_table
[ctl_node
- head
->node
];
118 procname
= entry
->procname
;
120 cmp
= namecmp(name
, namelen
, procname
, strlen(procname
));
122 node
= node
->rb_left
;
124 node
= node
->rb_right
;
133 static int insert_entry(struct ctl_table_header
*head
, struct ctl_table
*entry
)
135 struct rb_node
*node
= &head
->node
[entry
- head
->ctl_table
].node
;
136 struct rb_node
**p
= &head
->parent
->root
.rb_node
;
137 struct rb_node
*parent
= NULL
;
138 const char *name
= entry
->procname
;
139 int namelen
= strlen(name
);
142 struct ctl_table_header
*parent_head
;
143 struct ctl_table
*parent_entry
;
144 struct ctl_node
*parent_node
;
145 const char *parent_name
;
149 parent_node
= rb_entry(parent
, struct ctl_node
, node
);
150 parent_head
= parent_node
->header
;
151 parent_entry
= &parent_head
->ctl_table
[parent_node
- parent_head
->node
];
152 parent_name
= parent_entry
->procname
;
154 cmp
= namecmp(name
, namelen
, parent_name
, strlen(parent_name
));
160 pr_err("sysctl duplicate entry: ");
161 sysctl_print_dir(head
->parent
);
162 pr_cont("/%s\n", entry
->procname
);
167 rb_link_node(node
, parent
, p
);
168 rb_insert_color(node
, &head
->parent
->root
);
172 static void erase_entry(struct ctl_table_header
*head
, struct ctl_table
*entry
)
174 struct rb_node
*node
= &head
->node
[entry
- head
->ctl_table
].node
;
176 rb_erase(node
, &head
->parent
->root
);
179 static void init_header(struct ctl_table_header
*head
,
180 struct ctl_table_root
*root
, struct ctl_table_set
*set
,
181 struct ctl_node
*node
, struct ctl_table
*table
)
183 head
->ctl_table
= table
;
184 head
->ctl_table_arg
= table
;
188 head
->unregistering
= NULL
;
193 INIT_LIST_HEAD(&head
->inodes
);
195 struct ctl_table
*entry
;
196 for (entry
= table
; entry
->procname
; entry
++, node
++)
201 static void erase_header(struct ctl_table_header
*head
)
203 struct ctl_table
*entry
;
204 for (entry
= head
->ctl_table
; entry
->procname
; entry
++)
205 erase_entry(head
, entry
);
208 static int insert_header(struct ctl_dir
*dir
, struct ctl_table_header
*header
)
210 struct ctl_table
*entry
;
213 /* Is this a permanently empty directory? */
214 if (is_empty_dir(&dir
->header
))
217 /* Am I creating a permanently empty directory? */
218 if (header
->ctl_table
== sysctl_mount_point
) {
219 if (!RB_EMPTY_ROOT(&dir
->root
))
225 header
->parent
= dir
;
226 err
= insert_links(header
);
229 for (entry
= header
->ctl_table
; entry
->procname
; entry
++) {
230 err
= insert_entry(header
, entry
);
236 erase_header(header
);
239 if (header
->ctl_table
== sysctl_mount_point
)
240 clear_empty_dir(dir
);
241 header
->parent
= NULL
;
242 drop_sysctl_table(&dir
->header
);
246 /* called under sysctl_lock */
247 static int use_table(struct ctl_table_header
*p
)
249 if (unlikely(p
->unregistering
))
255 /* called under sysctl_lock */
256 static void unuse_table(struct ctl_table_header
*p
)
259 if (unlikely(p
->unregistering
))
260 complete(p
->unregistering
);
263 /* called under sysctl_lock */
264 static void proc_sys_prune_dcache(struct ctl_table_header
*head
)
266 struct inode
*inode
, *prev
= NULL
;
267 struct proc_inode
*ei
;
270 list_for_each_entry_rcu(ei
, &head
->inodes
, sysctl_inodes
) {
271 inode
= igrab(&ei
->vfs_inode
);
276 d_prune_aliases(inode
);
284 /* called under sysctl_lock, will reacquire if has to wait */
285 static void start_unregistering(struct ctl_table_header
*p
)
288 * if p->used is 0, nobody will ever touch that entry again;
289 * we'll eliminate all paths to it before dropping sysctl_lock
291 if (unlikely(p
->used
)) {
292 struct completion wait
;
293 init_completion(&wait
);
294 p
->unregistering
= &wait
;
295 spin_unlock(&sysctl_lock
);
296 wait_for_completion(&wait
);
298 /* anything non-NULL; we'll never dereference it */
299 p
->unregistering
= ERR_PTR(-EINVAL
);
300 spin_unlock(&sysctl_lock
);
303 * Prune dentries for unregistered sysctls: namespaced sysctls
304 * can have duplicate names and contaminate dcache very badly.
306 proc_sys_prune_dcache(p
);
308 * do not remove from the list until nobody holds it; walking the
309 * list in do_sysctl() relies on that.
311 spin_lock(&sysctl_lock
);
315 static struct ctl_table_header
*sysctl_head_grab(struct ctl_table_header
*head
)
318 spin_lock(&sysctl_lock
);
319 if (!use_table(head
))
320 head
= ERR_PTR(-ENOENT
);
321 spin_unlock(&sysctl_lock
);
325 static void sysctl_head_finish(struct ctl_table_header
*head
)
329 spin_lock(&sysctl_lock
);
331 spin_unlock(&sysctl_lock
);
334 static struct ctl_table_set
*
335 lookup_header_set(struct ctl_table_root
*root
)
337 struct ctl_table_set
*set
= &root
->default_set
;
339 set
= root
->lookup(root
);
343 static struct ctl_table
*lookup_entry(struct ctl_table_header
**phead
,
345 const char *name
, int namelen
)
347 struct ctl_table_header
*head
;
348 struct ctl_table
*entry
;
350 spin_lock(&sysctl_lock
);
351 entry
= find_entry(&head
, dir
, name
, namelen
);
352 if (entry
&& use_table(head
))
356 spin_unlock(&sysctl_lock
);
360 static struct ctl_node
*first_usable_entry(struct rb_node
*node
)
362 struct ctl_node
*ctl_node
;
364 for (;node
; node
= rb_next(node
)) {
365 ctl_node
= rb_entry(node
, struct ctl_node
, node
);
366 if (use_table(ctl_node
->header
))
372 static void first_entry(struct ctl_dir
*dir
,
373 struct ctl_table_header
**phead
, struct ctl_table
**pentry
)
375 struct ctl_table_header
*head
= NULL
;
376 struct ctl_table
*entry
= NULL
;
377 struct ctl_node
*ctl_node
;
379 spin_lock(&sysctl_lock
);
380 ctl_node
= first_usable_entry(rb_first(&dir
->root
));
381 spin_unlock(&sysctl_lock
);
383 head
= ctl_node
->header
;
384 entry
= &head
->ctl_table
[ctl_node
- head
->node
];
390 static void next_entry(struct ctl_table_header
**phead
, struct ctl_table
**pentry
)
392 struct ctl_table_header
*head
= *phead
;
393 struct ctl_table
*entry
= *pentry
;
394 struct ctl_node
*ctl_node
= &head
->node
[entry
- head
->ctl_table
];
396 spin_lock(&sysctl_lock
);
399 ctl_node
= first_usable_entry(rb_next(&ctl_node
->node
));
400 spin_unlock(&sysctl_lock
);
403 head
= ctl_node
->header
;
404 entry
= &head
->ctl_table
[ctl_node
- head
->node
];
410 void register_sysctl_root(struct ctl_table_root
*root
)
415 * sysctl_perm does NOT grant the superuser all rights automatically, because
416 * some sysctl variables are readonly even to root.
419 static int test_perm(int mode
, int op
)
421 if (uid_eq(current_euid(), GLOBAL_ROOT_UID
))
423 else if (in_egroup_p(GLOBAL_ROOT_GID
))
425 if ((op
& ~mode
& (MAY_READ
|MAY_WRITE
|MAY_EXEC
)) == 0)
430 static int sysctl_perm(struct ctl_table_header
*head
, struct ctl_table
*table
, int op
)
432 struct ctl_table_root
*root
= head
->root
;
435 if (root
->permissions
)
436 mode
= root
->permissions(head
, table
);
440 return test_perm(mode
, op
);
443 static struct inode
*proc_sys_make_inode(struct super_block
*sb
,
444 struct ctl_table_header
*head
, struct ctl_table
*table
)
446 struct ctl_table_root
*root
= head
->root
;
448 struct proc_inode
*ei
;
450 inode
= new_inode(sb
);
454 inode
->i_ino
= get_next_ino();
458 spin_lock(&sysctl_lock
);
459 if (unlikely(head
->unregistering
)) {
460 spin_unlock(&sysctl_lock
);
466 ei
->sysctl_entry
= table
;
467 list_add_rcu(&ei
->sysctl_inodes
, &head
->inodes
);
469 spin_unlock(&sysctl_lock
);
471 inode
->i_mtime
= inode
->i_atime
= inode
->i_ctime
= current_time(inode
);
472 inode
->i_mode
= table
->mode
;
473 if (!S_ISDIR(table
->mode
)) {
474 inode
->i_mode
|= S_IFREG
;
475 inode
->i_op
= &proc_sys_inode_operations
;
476 inode
->i_fop
= &proc_sys_file_operations
;
478 inode
->i_mode
|= S_IFDIR
;
479 inode
->i_op
= &proc_sys_dir_operations
;
480 inode
->i_fop
= &proc_sys_dir_file_operations
;
481 if (is_empty_dir(head
))
482 make_empty_dir_inode(inode
);
485 if (root
->set_ownership
)
486 root
->set_ownership(head
, table
, &inode
->i_uid
, &inode
->i_gid
);
492 void proc_sys_evict_inode(struct inode
*inode
, struct ctl_table_header
*head
)
494 spin_lock(&sysctl_lock
);
495 list_del_rcu(&PROC_I(inode
)->sysctl_inodes
);
497 kfree_rcu(head
, rcu
);
498 spin_unlock(&sysctl_lock
);
501 static struct ctl_table_header
*grab_header(struct inode
*inode
)
503 struct ctl_table_header
*head
= PROC_I(inode
)->sysctl
;
505 head
= &sysctl_table_root
.default_set
.dir
.header
;
506 return sysctl_head_grab(head
);
509 static struct dentry
*proc_sys_lookup(struct inode
*dir
, struct dentry
*dentry
,
512 struct ctl_table_header
*head
= grab_header(dir
);
513 struct ctl_table_header
*h
= NULL
;
514 const struct qstr
*name
= &dentry
->d_name
;
517 struct dentry
*err
= ERR_PTR(-ENOENT
);
518 struct ctl_dir
*ctl_dir
;
522 return ERR_CAST(head
);
524 ctl_dir
= container_of(head
, struct ctl_dir
, header
);
526 p
= lookup_entry(&h
, ctl_dir
, name
->name
, name
->len
);
530 if (S_ISLNK(p
->mode
)) {
531 ret
= sysctl_follow_link(&h
, &p
);
537 err
= ERR_PTR(-ENOMEM
);
538 inode
= proc_sys_make_inode(dir
->i_sb
, h
? h
: head
, p
);
543 d_set_d_op(dentry
, &proc_sys_dentry_operations
);
544 d_add(dentry
, inode
);
548 sysctl_head_finish(h
);
549 sysctl_head_finish(head
);
553 static ssize_t
proc_sys_call_handler(struct file
*filp
, void __user
*buf
,
554 size_t count
, loff_t
*ppos
, int write
)
556 struct inode
*inode
= file_inode(filp
);
557 struct ctl_table_header
*head
= grab_header(inode
);
558 struct ctl_table
*table
= PROC_I(inode
)->sysctl_entry
;
563 return PTR_ERR(head
);
566 * At this point we know that the sysctl was not unregistered
567 * and won't be until we finish.
570 if (sysctl_perm(head
, table
, write
? MAY_WRITE
: MAY_READ
))
573 /* if that can happen at all, it should be -EINVAL, not -EISDIR */
575 if (!table
->proc_handler
)
578 /* careful: calling conventions are nasty here */
580 error
= table
->proc_handler(table
, write
, buf
, &res
, ppos
);
584 sysctl_head_finish(head
);
589 static ssize_t
proc_sys_read(struct file
*filp
, char __user
*buf
,
590 size_t count
, loff_t
*ppos
)
592 return proc_sys_call_handler(filp
, (void __user
*)buf
, count
, ppos
, 0);
595 static ssize_t
proc_sys_write(struct file
*filp
, const char __user
*buf
,
596 size_t count
, loff_t
*ppos
)
598 return proc_sys_call_handler(filp
, (void __user
*)buf
, count
, ppos
, 1);
601 static int proc_sys_open(struct inode
*inode
, struct file
*filp
)
603 struct ctl_table_header
*head
= grab_header(inode
);
604 struct ctl_table
*table
= PROC_I(inode
)->sysctl_entry
;
606 /* sysctl was unregistered */
608 return PTR_ERR(head
);
611 filp
->private_data
= proc_sys_poll_event(table
->poll
);
613 sysctl_head_finish(head
);
618 static unsigned int proc_sys_poll(struct file
*filp
, poll_table
*wait
)
620 struct inode
*inode
= file_inode(filp
);
621 struct ctl_table_header
*head
= grab_header(inode
);
622 struct ctl_table
*table
= PROC_I(inode
)->sysctl_entry
;
623 unsigned int ret
= DEFAULT_POLLMASK
;
626 /* sysctl was unregistered */
628 return POLLERR
| POLLHUP
;
630 if (!table
->proc_handler
)
636 event
= (unsigned long)filp
->private_data
;
637 poll_wait(filp
, &table
->poll
->wait
, wait
);
639 if (event
!= atomic_read(&table
->poll
->event
)) {
640 filp
->private_data
= proc_sys_poll_event(table
->poll
);
641 ret
= POLLIN
| POLLRDNORM
| POLLERR
| POLLPRI
;
645 sysctl_head_finish(head
);
650 static bool proc_sys_fill_cache(struct file
*file
,
651 struct dir_context
*ctx
,
652 struct ctl_table_header
*head
,
653 struct ctl_table
*table
)
655 struct dentry
*child
, *dir
= file
->f_path
.dentry
;
659 unsigned type
= DT_UNKNOWN
;
661 qname
.name
= table
->procname
;
662 qname
.len
= strlen(table
->procname
);
663 qname
.hash
= full_name_hash(dir
, qname
.name
, qname
.len
);
665 child
= d_lookup(dir
, &qname
);
667 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq
);
668 child
= d_alloc_parallel(dir
, &qname
, &wq
);
671 if (d_in_lookup(child
)) {
672 inode
= proc_sys_make_inode(dir
->d_sb
, head
, table
);
674 d_lookup_done(child
);
678 d_set_d_op(child
, &proc_sys_dentry_operations
);
682 inode
= d_inode(child
);
684 type
= inode
->i_mode
>> 12;
686 return dir_emit(ctx
, qname
.name
, qname
.len
, ino
, type
);
689 static bool proc_sys_link_fill_cache(struct file
*file
,
690 struct dir_context
*ctx
,
691 struct ctl_table_header
*head
,
692 struct ctl_table
*table
)
695 head
= sysctl_head_grab(head
);
697 if (S_ISLNK(table
->mode
)) {
698 /* It is not an error if we can not follow the link ignore it */
699 int err
= sysctl_follow_link(&head
, &table
);
704 ret
= proc_sys_fill_cache(file
, ctx
, head
, table
);
706 sysctl_head_finish(head
);
710 static int scan(struct ctl_table_header
*head
, struct ctl_table
*table
,
711 unsigned long *pos
, struct file
*file
,
712 struct dir_context
*ctx
)
716 if ((*pos
)++ < ctx
->pos
)
719 if (unlikely(S_ISLNK(table
->mode
)))
720 res
= proc_sys_link_fill_cache(file
, ctx
, head
, table
);
722 res
= proc_sys_fill_cache(file
, ctx
, head
, table
);
730 static int proc_sys_readdir(struct file
*file
, struct dir_context
*ctx
)
732 struct ctl_table_header
*head
= grab_header(file_inode(file
));
733 struct ctl_table_header
*h
= NULL
;
734 struct ctl_table
*entry
;
735 struct ctl_dir
*ctl_dir
;
739 return PTR_ERR(head
);
741 ctl_dir
= container_of(head
, struct ctl_dir
, header
);
743 if (!dir_emit_dots(file
, ctx
))
748 for (first_entry(ctl_dir
, &h
, &entry
); h
; next_entry(&h
, &entry
)) {
749 if (!scan(h
, entry
, &pos
, file
, ctx
)) {
750 sysctl_head_finish(h
);
755 sysctl_head_finish(head
);
759 static int proc_sys_permission(struct inode
*inode
, int mask
)
762 * sysctl entries that are not writeable,
763 * are _NOT_ writeable, capabilities or not.
765 struct ctl_table_header
*head
;
766 struct ctl_table
*table
;
769 /* Executable files are not allowed under /proc/sys/ */
770 if ((mask
& MAY_EXEC
) && S_ISREG(inode
->i_mode
))
773 head
= grab_header(inode
);
775 return PTR_ERR(head
);
777 table
= PROC_I(inode
)->sysctl_entry
;
778 if (!table
) /* global root - r-xr-xr-x */
779 error
= mask
& MAY_WRITE
? -EACCES
: 0;
780 else /* Use the permissions on the sysctl table entry */
781 error
= sysctl_perm(head
, table
, mask
& ~MAY_NOT_BLOCK
);
783 sysctl_head_finish(head
);
787 static int proc_sys_setattr(struct dentry
*dentry
, struct iattr
*attr
)
789 struct inode
*inode
= d_inode(dentry
);
792 if (attr
->ia_valid
& (ATTR_MODE
| ATTR_UID
| ATTR_GID
))
795 error
= setattr_prepare(dentry
, attr
);
799 setattr_copy(inode
, attr
);
800 mark_inode_dirty(inode
);
804 static int proc_sys_getattr(struct vfsmount
*mnt
, struct dentry
*dentry
, struct kstat
*stat
)
806 struct inode
*inode
= d_inode(dentry
);
807 struct ctl_table_header
*head
= grab_header(inode
);
808 struct ctl_table
*table
= PROC_I(inode
)->sysctl_entry
;
811 return PTR_ERR(head
);
813 generic_fillattr(inode
, stat
);
815 stat
->mode
= (stat
->mode
& S_IFMT
) | table
->mode
;
817 sysctl_head_finish(head
);
821 static const struct file_operations proc_sys_file_operations
= {
822 .open
= proc_sys_open
,
823 .poll
= proc_sys_poll
,
824 .read
= proc_sys_read
,
825 .write
= proc_sys_write
,
826 .llseek
= default_llseek
,
829 static const struct file_operations proc_sys_dir_file_operations
= {
830 .read
= generic_read_dir
,
831 .iterate_shared
= proc_sys_readdir
,
832 .llseek
= generic_file_llseek
,
835 static const struct inode_operations proc_sys_inode_operations
= {
836 .permission
= proc_sys_permission
,
837 .setattr
= proc_sys_setattr
,
838 .getattr
= proc_sys_getattr
,
841 static const struct inode_operations proc_sys_dir_operations
= {
842 .lookup
= proc_sys_lookup
,
843 .permission
= proc_sys_permission
,
844 .setattr
= proc_sys_setattr
,
845 .getattr
= proc_sys_getattr
,
848 static int proc_sys_revalidate(struct dentry
*dentry
, unsigned int flags
)
850 if (flags
& LOOKUP_RCU
)
852 return !PROC_I(d_inode(dentry
))->sysctl
->unregistering
;
855 static int proc_sys_delete(const struct dentry
*dentry
)
857 return !!PROC_I(d_inode(dentry
))->sysctl
->unregistering
;
860 static int sysctl_is_seen(struct ctl_table_header
*p
)
862 struct ctl_table_set
*set
= p
->set
;
864 spin_lock(&sysctl_lock
);
865 if (p
->unregistering
)
867 else if (!set
->is_seen
)
870 res
= set
->is_seen(set
);
871 spin_unlock(&sysctl_lock
);
875 static int proc_sys_compare(const struct dentry
*dentry
,
876 unsigned int len
, const char *str
, const struct qstr
*name
)
878 struct ctl_table_header
*head
;
881 /* Although proc doesn't have negative dentries, rcu-walk means
882 * that inode here can be NULL */
883 /* AV: can it, indeed? */
884 inode
= d_inode_rcu(dentry
);
887 if (name
->len
!= len
)
889 if (memcmp(name
->name
, str
, len
))
891 head
= rcu_dereference(PROC_I(inode
)->sysctl
);
892 return !head
|| !sysctl_is_seen(head
);
895 static const struct dentry_operations proc_sys_dentry_operations
= {
896 .d_revalidate
= proc_sys_revalidate
,
897 .d_delete
= proc_sys_delete
,
898 .d_compare
= proc_sys_compare
,
901 static struct ctl_dir
*find_subdir(struct ctl_dir
*dir
,
902 const char *name
, int namelen
)
904 struct ctl_table_header
*head
;
905 struct ctl_table
*entry
;
907 entry
= find_entry(&head
, dir
, name
, namelen
);
909 return ERR_PTR(-ENOENT
);
910 if (!S_ISDIR(entry
->mode
))
911 return ERR_PTR(-ENOTDIR
);
912 return container_of(head
, struct ctl_dir
, header
);
915 static struct ctl_dir
*new_dir(struct ctl_table_set
*set
,
916 const char *name
, int namelen
)
918 struct ctl_table
*table
;
920 struct ctl_node
*node
;
923 new = kzalloc(sizeof(*new) + sizeof(struct ctl_node
) +
924 sizeof(struct ctl_table
)*2 + namelen
+ 1,
929 node
= (struct ctl_node
*)(new + 1);
930 table
= (struct ctl_table
*)(node
+ 1);
931 new_name
= (char *)(table
+ 2);
932 memcpy(new_name
, name
, namelen
);
933 new_name
[namelen
] = '\0';
934 table
[0].procname
= new_name
;
935 table
[0].mode
= S_IFDIR
|S_IRUGO
|S_IXUGO
;
936 init_header(&new->header
, set
->dir
.header
.root
, set
, node
, table
);
942 * get_subdir - find or create a subdir with the specified name.
943 * @dir: Directory to create the subdirectory in
944 * @name: The name of the subdirectory to find or create
945 * @namelen: The length of name
947 * Takes a directory with an elevated reference count so we know that
948 * if we drop the lock the directory will not go away. Upon success
949 * the reference is moved from @dir to the returned subdirectory.
950 * Upon error an error code is returned and the reference on @dir is
953 static struct ctl_dir
*get_subdir(struct ctl_dir
*dir
,
954 const char *name
, int namelen
)
956 struct ctl_table_set
*set
= dir
->header
.set
;
957 struct ctl_dir
*subdir
, *new = NULL
;
960 spin_lock(&sysctl_lock
);
961 subdir
= find_subdir(dir
, name
, namelen
);
964 if (PTR_ERR(subdir
) != -ENOENT
)
967 spin_unlock(&sysctl_lock
);
968 new = new_dir(set
, name
, namelen
);
969 spin_lock(&sysctl_lock
);
970 subdir
= ERR_PTR(-ENOMEM
);
974 /* Was the subdir added while we dropped the lock? */
975 subdir
= find_subdir(dir
, name
, namelen
);
978 if (PTR_ERR(subdir
) != -ENOENT
)
981 /* Nope. Use the our freshly made directory entry. */
982 err
= insert_header(dir
, &new->header
);
983 subdir
= ERR_PTR(err
);
988 subdir
->header
.nreg
++;
990 if (IS_ERR(subdir
)) {
991 pr_err("sysctl could not get directory: ");
992 sysctl_print_dir(dir
);
993 pr_cont("/%*.*s %ld\n",
994 namelen
, namelen
, name
, PTR_ERR(subdir
));
996 drop_sysctl_table(&dir
->header
);
998 drop_sysctl_table(&new->header
);
999 spin_unlock(&sysctl_lock
);
1003 static struct ctl_dir
*xlate_dir(struct ctl_table_set
*set
, struct ctl_dir
*dir
)
1005 struct ctl_dir
*parent
;
1006 const char *procname
;
1007 if (!dir
->header
.parent
)
1009 parent
= xlate_dir(set
, dir
->header
.parent
);
1012 procname
= dir
->header
.ctl_table
[0].procname
;
1013 return find_subdir(parent
, procname
, strlen(procname
));
1016 static int sysctl_follow_link(struct ctl_table_header
**phead
,
1017 struct ctl_table
**pentry
)
1019 struct ctl_table_header
*head
;
1020 struct ctl_table_root
*root
;
1021 struct ctl_table_set
*set
;
1022 struct ctl_table
*entry
;
1023 struct ctl_dir
*dir
;
1027 spin_lock(&sysctl_lock
);
1028 root
= (*pentry
)->data
;
1029 set
= lookup_header_set(root
);
1030 dir
= xlate_dir(set
, (*phead
)->parent
);
1034 const char *procname
= (*pentry
)->procname
;
1036 entry
= find_entry(&head
, dir
, procname
, strlen(procname
));
1038 if (entry
&& use_table(head
)) {
1039 unuse_table(*phead
);
1046 spin_unlock(&sysctl_lock
);
1050 static int sysctl_err(const char *path
, struct ctl_table
*table
, char *fmt
, ...)
1052 struct va_format vaf
;
1055 va_start(args
, fmt
);
1059 pr_err("sysctl table check failed: %s/%s %pV\n",
1060 path
, table
->procname
, &vaf
);
1066 static int sysctl_check_table(const char *path
, struct ctl_table
*table
)
1069 for (; table
->procname
; table
++) {
1071 err
= sysctl_err(path
, table
, "Not a file");
1073 if ((table
->proc_handler
== proc_dostring
) ||
1074 (table
->proc_handler
== proc_dointvec
) ||
1075 (table
->proc_handler
== proc_dointvec_minmax
) ||
1076 (table
->proc_handler
== proc_dointvec_jiffies
) ||
1077 (table
->proc_handler
== proc_dointvec_userhz_jiffies
) ||
1078 (table
->proc_handler
== proc_dointvec_ms_jiffies
) ||
1079 (table
->proc_handler
== proc_doulongvec_minmax
) ||
1080 (table
->proc_handler
== proc_doulongvec_ms_jiffies_minmax
)) {
1082 err
= sysctl_err(path
, table
, "No data");
1084 err
= sysctl_err(path
, table
, "No maxlen");
1086 if (!table
->proc_handler
)
1087 err
= sysctl_err(path
, table
, "No proc_handler");
1089 if ((table
->mode
& (S_IRUGO
|S_IWUGO
)) != table
->mode
)
1090 err
= sysctl_err(path
, table
, "bogus .mode 0%o",
1096 static struct ctl_table_header
*new_links(struct ctl_dir
*dir
, struct ctl_table
*table
,
1097 struct ctl_table_root
*link_root
)
1099 struct ctl_table
*link_table
, *entry
, *link
;
1100 struct ctl_table_header
*links
;
1101 struct ctl_node
*node
;
1103 int nr_entries
, name_bytes
;
1107 for (entry
= table
; entry
->procname
; entry
++) {
1109 name_bytes
+= strlen(entry
->procname
) + 1;
1112 links
= kzalloc(sizeof(struct ctl_table_header
) +
1113 sizeof(struct ctl_node
)*nr_entries
+
1114 sizeof(struct ctl_table
)*(nr_entries
+ 1) +
1121 node
= (struct ctl_node
*)(links
+ 1);
1122 link_table
= (struct ctl_table
*)(node
+ nr_entries
);
1123 link_name
= (char *)&link_table
[nr_entries
+ 1];
1125 for (link
= link_table
, entry
= table
; entry
->procname
; link
++, entry
++) {
1126 int len
= strlen(entry
->procname
) + 1;
1127 memcpy(link_name
, entry
->procname
, len
);
1128 link
->procname
= link_name
;
1129 link
->mode
= S_IFLNK
|S_IRWXUGO
;
1130 link
->data
= link_root
;
1133 init_header(links
, dir
->header
.root
, dir
->header
.set
, node
, link_table
);
1134 links
->nreg
= nr_entries
;
1139 static bool get_links(struct ctl_dir
*dir
,
1140 struct ctl_table
*table
, struct ctl_table_root
*link_root
)
1142 struct ctl_table_header
*head
;
1143 struct ctl_table
*entry
, *link
;
1145 /* Are there links available for every entry in table? */
1146 for (entry
= table
; entry
->procname
; entry
++) {
1147 const char *procname
= entry
->procname
;
1148 link
= find_entry(&head
, dir
, procname
, strlen(procname
));
1151 if (S_ISDIR(link
->mode
) && S_ISDIR(entry
->mode
))
1153 if (S_ISLNK(link
->mode
) && (link
->data
== link_root
))
1158 /* The checks passed. Increase the registration count on the links */
1159 for (entry
= table
; entry
->procname
; entry
++) {
1160 const char *procname
= entry
->procname
;
1161 link
= find_entry(&head
, dir
, procname
, strlen(procname
));
1167 static int insert_links(struct ctl_table_header
*head
)
1169 struct ctl_table_set
*root_set
= &sysctl_table_root
.default_set
;
1170 struct ctl_dir
*core_parent
= NULL
;
1171 struct ctl_table_header
*links
;
1174 if (head
->set
== root_set
)
1177 core_parent
= xlate_dir(root_set
, head
->parent
);
1178 if (IS_ERR(core_parent
))
1181 if (get_links(core_parent
, head
->ctl_table
, head
->root
))
1184 core_parent
->header
.nreg
++;
1185 spin_unlock(&sysctl_lock
);
1187 links
= new_links(core_parent
, head
->ctl_table
, head
->root
);
1189 spin_lock(&sysctl_lock
);
1195 if (get_links(core_parent
, head
->ctl_table
, head
->root
)) {
1200 err
= insert_header(core_parent
, links
);
1204 drop_sysctl_table(&core_parent
->header
);
1209 * __register_sysctl_table - register a leaf sysctl table
1210 * @set: Sysctl tree to register on
1211 * @path: The path to the directory the sysctl table is in.
1212 * @table: the top-level table structure
1214 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1215 * array. A completely 0 filled entry terminates the table.
1217 * The members of the &struct ctl_table structure are used as follows:
1219 * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
1220 * enter a sysctl file
1222 * data - a pointer to data for use by proc_handler
1224 * maxlen - the maximum size in bytes of the data
1226 * mode - the file permissions for the /proc/sys file
1228 * child - must be %NULL.
1230 * proc_handler - the text handler routine (described below)
1232 * extra1, extra2 - extra pointers usable by the proc handler routines
1234 * Leaf nodes in the sysctl tree will be represented by a single file
1235 * under /proc; non-leaf nodes will be represented by directories.
1237 * There must be a proc_handler routine for any terminal nodes.
1238 * Several default handlers are available to cover common cases -
1240 * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
1241 * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
1242 * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
1244 * It is the handler's job to read the input buffer from user memory
1245 * and process it. The handler should return 0 on success.
1247 * This routine returns %NULL on a failure to register, and a pointer
1248 * to the table header on success.
1250 struct ctl_table_header
*__register_sysctl_table(
1251 struct ctl_table_set
*set
,
1252 const char *path
, struct ctl_table
*table
)
1254 struct ctl_table_root
*root
= set
->dir
.header
.root
;
1255 struct ctl_table_header
*header
;
1256 const char *name
, *nextname
;
1257 struct ctl_dir
*dir
;
1258 struct ctl_table
*entry
;
1259 struct ctl_node
*node
;
1262 for (entry
= table
; entry
->procname
; entry
++)
1265 header
= kzalloc(sizeof(struct ctl_table_header
) +
1266 sizeof(struct ctl_node
)*nr_entries
, GFP_KERNEL
);
1270 node
= (struct ctl_node
*)(header
+ 1);
1271 init_header(header
, root
, set
, node
, table
);
1272 if (sysctl_check_table(path
, table
))
1275 spin_lock(&sysctl_lock
);
1277 /* Reference moved down the diretory tree get_subdir */
1279 spin_unlock(&sysctl_lock
);
1281 /* Find the directory for the ctl_table */
1282 for (name
= path
; name
; name
= nextname
) {
1284 nextname
= strchr(name
, '/');
1286 namelen
= nextname
- name
;
1289 namelen
= strlen(name
);
1294 dir
= get_subdir(dir
, name
, namelen
);
1299 spin_lock(&sysctl_lock
);
1300 if (insert_header(dir
, header
))
1301 goto fail_put_dir_locked
;
1303 drop_sysctl_table(&dir
->header
);
1304 spin_unlock(&sysctl_lock
);
1308 fail_put_dir_locked
:
1309 drop_sysctl_table(&dir
->header
);
1310 spin_unlock(&sysctl_lock
);
1318 * register_sysctl - register a sysctl table
1319 * @path: The path to the directory the sysctl table is in.
1320 * @table: the table structure
1322 * Register a sysctl table. @table should be a filled in ctl_table
1323 * array. A completely 0 filled entry terminates the table.
1325 * See __register_sysctl_table for more details.
1327 struct ctl_table_header
*register_sysctl(const char *path
, struct ctl_table
*table
)
1329 return __register_sysctl_table(&sysctl_table_root
.default_set
,
1332 EXPORT_SYMBOL(register_sysctl
);
1334 static char *append_path(const char *path
, char *pos
, const char *name
)
1337 namelen
= strlen(name
);
1338 if (((pos
- path
) + namelen
+ 2) >= PATH_MAX
)
1340 memcpy(pos
, name
, namelen
);
1342 pos
[namelen
+ 1] = '\0';
1347 static int count_subheaders(struct ctl_table
*table
)
1350 int nr_subheaders
= 0;
1351 struct ctl_table
*entry
;
1353 /* special case: no directory and empty directory */
1354 if (!table
|| !table
->procname
)
1357 for (entry
= table
; entry
->procname
; entry
++) {
1359 nr_subheaders
+= count_subheaders(entry
->child
);
1363 return nr_subheaders
+ has_files
;
1366 static int register_leaf_sysctl_tables(const char *path
, char *pos
,
1367 struct ctl_table_header
***subheader
, struct ctl_table_set
*set
,
1368 struct ctl_table
*table
)
1370 struct ctl_table
*ctl_table_arg
= NULL
;
1371 struct ctl_table
*entry
, *files
;
1376 for (entry
= table
; entry
->procname
; entry
++) {
1384 /* If there are mixed files and directories we need a new table */
1385 if (nr_dirs
&& nr_files
) {
1386 struct ctl_table
*new;
1387 files
= kzalloc(sizeof(struct ctl_table
) * (nr_files
+ 1),
1392 ctl_table_arg
= files
;
1393 for (new = files
, entry
= table
; entry
->procname
; entry
++) {
1401 /* Register everything except a directory full of subdirectories */
1402 if (nr_files
|| !nr_dirs
) {
1403 struct ctl_table_header
*header
;
1404 header
= __register_sysctl_table(set
, path
, files
);
1406 kfree(ctl_table_arg
);
1410 /* Remember if we need to free the file table */
1411 header
->ctl_table_arg
= ctl_table_arg
;
1412 **subheader
= header
;
1416 /* Recurse into the subdirectories. */
1417 for (entry
= table
; entry
->procname
; entry
++) {
1423 err
= -ENAMETOOLONG
;
1424 child_pos
= append_path(path
, pos
, entry
->procname
);
1428 err
= register_leaf_sysctl_tables(path
, child_pos
, subheader
,
1436 /* On failure our caller will unregister all registered subheaders */
1441 * __register_sysctl_paths - register a sysctl table hierarchy
1442 * @set: Sysctl tree to register on
1443 * @path: The path to the directory the sysctl table is in.
1444 * @table: the top-level table structure
1446 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1447 * array. A completely 0 filled entry terminates the table.
1449 * See __register_sysctl_table for more details.
1451 struct ctl_table_header
*__register_sysctl_paths(
1452 struct ctl_table_set
*set
,
1453 const struct ctl_path
*path
, struct ctl_table
*table
)
1455 struct ctl_table
*ctl_table_arg
= table
;
1456 int nr_subheaders
= count_subheaders(table
);
1457 struct ctl_table_header
*header
= NULL
, **subheaders
, **subheader
;
1458 const struct ctl_path
*component
;
1459 char *new_path
, *pos
;
1461 pos
= new_path
= kmalloc(PATH_MAX
, GFP_KERNEL
);
1466 for (component
= path
; component
->procname
; component
++) {
1467 pos
= append_path(new_path
, pos
, component
->procname
);
1471 while (table
->procname
&& table
->child
&& !table
[1].procname
) {
1472 pos
= append_path(new_path
, pos
, table
->procname
);
1475 table
= table
->child
;
1477 if (nr_subheaders
== 1) {
1478 header
= __register_sysctl_table(set
, new_path
, table
);
1480 header
->ctl_table_arg
= ctl_table_arg
;
1482 header
= kzalloc(sizeof(*header
) +
1483 sizeof(*subheaders
)*nr_subheaders
, GFP_KERNEL
);
1487 subheaders
= (struct ctl_table_header
**) (header
+ 1);
1488 subheader
= subheaders
;
1489 header
->ctl_table_arg
= ctl_table_arg
;
1491 if (register_leaf_sysctl_tables(new_path
, pos
, &subheader
,
1493 goto err_register_leaves
;
1500 err_register_leaves
:
1501 while (subheader
> subheaders
) {
1502 struct ctl_table_header
*subh
= *(--subheader
);
1503 struct ctl_table
*table
= subh
->ctl_table_arg
;
1504 unregister_sysctl_table(subh
);
1513 * register_sysctl_table_path - register a sysctl table hierarchy
1514 * @path: The path to the directory the sysctl table is in.
1515 * @table: the top-level table structure
1517 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1518 * array. A completely 0 filled entry terminates the table.
1520 * See __register_sysctl_paths for more details.
1522 struct ctl_table_header
*register_sysctl_paths(const struct ctl_path
*path
,
1523 struct ctl_table
*table
)
1525 return __register_sysctl_paths(&sysctl_table_root
.default_set
,
1528 EXPORT_SYMBOL(register_sysctl_paths
);
1531 * register_sysctl_table - register a sysctl table hierarchy
1532 * @table: the top-level table structure
1534 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1535 * array. A completely 0 filled entry terminates the table.
1537 * See register_sysctl_paths for more details.
1539 struct ctl_table_header
*register_sysctl_table(struct ctl_table
*table
)
1541 static const struct ctl_path null_path
[] = { {} };
1543 return register_sysctl_paths(null_path
, table
);
1545 EXPORT_SYMBOL(register_sysctl_table
);
1547 static void put_links(struct ctl_table_header
*header
)
1549 struct ctl_table_set
*root_set
= &sysctl_table_root
.default_set
;
1550 struct ctl_table_root
*root
= header
->root
;
1551 struct ctl_dir
*parent
= header
->parent
;
1552 struct ctl_dir
*core_parent
;
1553 struct ctl_table
*entry
;
1555 if (header
->set
== root_set
)
1558 core_parent
= xlate_dir(root_set
, parent
);
1559 if (IS_ERR(core_parent
))
1562 for (entry
= header
->ctl_table
; entry
->procname
; entry
++) {
1563 struct ctl_table_header
*link_head
;
1564 struct ctl_table
*link
;
1565 const char *name
= entry
->procname
;
1567 link
= find_entry(&link_head
, core_parent
, name
, strlen(name
));
1569 ((S_ISDIR(link
->mode
) && S_ISDIR(entry
->mode
)) ||
1570 (S_ISLNK(link
->mode
) && (link
->data
== root
)))) {
1571 drop_sysctl_table(link_head
);
1574 pr_err("sysctl link missing during unregister: ");
1575 sysctl_print_dir(parent
);
1576 pr_cont("/%s\n", name
);
1581 static void drop_sysctl_table(struct ctl_table_header
*header
)
1583 struct ctl_dir
*parent
= header
->parent
;
1589 start_unregistering(header
);
1590 if (!--header
->count
)
1591 kfree_rcu(header
, rcu
);
1594 drop_sysctl_table(&parent
->header
);
1598 * unregister_sysctl_table - unregister a sysctl table hierarchy
1599 * @header: the header returned from register_sysctl_table
1601 * Unregisters the sysctl table and all children. proc entries may not
1602 * actually be removed until they are no longer used by anyone.
1604 void unregister_sysctl_table(struct ctl_table_header
* header
)
1612 nr_subheaders
= count_subheaders(header
->ctl_table_arg
);
1613 if (unlikely(nr_subheaders
> 1)) {
1614 struct ctl_table_header
**subheaders
;
1617 subheaders
= (struct ctl_table_header
**)(header
+ 1);
1618 for (i
= nr_subheaders
-1; i
>= 0; i
--) {
1619 struct ctl_table_header
*subh
= subheaders
[i
];
1620 struct ctl_table
*table
= subh
->ctl_table_arg
;
1621 unregister_sysctl_table(subh
);
1628 spin_lock(&sysctl_lock
);
1629 drop_sysctl_table(header
);
1630 spin_unlock(&sysctl_lock
);
1632 EXPORT_SYMBOL(unregister_sysctl_table
);
1634 void setup_sysctl_set(struct ctl_table_set
*set
,
1635 struct ctl_table_root
*root
,
1636 int (*is_seen
)(struct ctl_table_set
*))
1638 memset(set
, 0, sizeof(*set
));
1639 set
->is_seen
= is_seen
;
1640 init_header(&set
->dir
.header
, root
, set
, NULL
, root_table
);
1643 void retire_sysctl_set(struct ctl_table_set
*set
)
1645 WARN_ON(!RB_EMPTY_ROOT(&set
->dir
.root
));
1648 int __init
proc_sys_init(void)
1650 struct proc_dir_entry
*proc_sys_root
;
1652 proc_sys_root
= proc_mkdir("sys", NULL
);
1653 proc_sys_root
->proc_iops
= &proc_sys_dir_operations
;
1654 proc_sys_root
->proc_fops
= &proc_sys_dir_file_operations
;
1655 proc_sys_root
->nlink
= 0;
1657 return sysctl_init();