1 // SPDX-License-Identifier: GPL-2.0
5 #include <linux/init.h>
6 #include <linux/sysctl.h>
7 #include <linux/poll.h>
8 #include <linux/proc_fs.h>
9 #include <linux/printk.h>
10 #include <linux/security.h>
11 #include <linux/sched.h>
12 #include <linux/cred.h>
13 #include <linux/namei.h>
15 #include <linux/uio.h>
16 #include <linux/module.h>
17 #include <linux/bpf-cgroup.h>
18 #include <linux/mount.h>
19 #include <linux/kmemleak.h>
22 #define list_for_each_table_entry(entry, table) \
23 for ((entry) = (table); (entry)->procname; (entry)++)
25 static const struct dentry_operations proc_sys_dentry_operations
;
26 static const struct file_operations proc_sys_file_operations
;
27 static const struct inode_operations proc_sys_inode_operations
;
28 static const struct file_operations proc_sys_dir_file_operations
;
29 static const struct inode_operations proc_sys_dir_operations
;
31 /* Support for permanently empty directories */
32 struct ctl_table sysctl_mount_point
[] = {
33 {.type
= SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY
}
37 * register_sysctl_mount_point() - registers a sysctl mount point
38 * @path: path for the mount point
40 * Used to create a permanently empty directory to serve as mount point.
41 * There are some subtle but important permission checks this allows in the
42 * case of unprivileged mounts.
44 struct ctl_table_header
*register_sysctl_mount_point(const char *path
)
46 return register_sysctl(path
, sysctl_mount_point
);
48 EXPORT_SYMBOL(register_sysctl_mount_point
);
50 #define sysctl_is_perm_empty_ctl_table(tptr) \
51 (tptr[0].type == SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY)
52 #define sysctl_is_perm_empty_ctl_header(hptr) \
53 (sysctl_is_perm_empty_ctl_table(hptr->ctl_table))
54 #define sysctl_set_perm_empty_ctl_header(hptr) \
55 (hptr->ctl_table[0].type = SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY)
56 #define sysctl_clear_perm_empty_ctl_header(hptr) \
57 (hptr->ctl_table[0].type = SYSCTL_TABLE_TYPE_DEFAULT)
59 void proc_sys_poll_notify(struct ctl_table_poll
*poll
)
64 atomic_inc(&poll
->event
);
65 wake_up_interruptible(&poll
->wait
);
68 static struct ctl_table root_table
[] = {
71 .mode
= S_IFDIR
|S_IRUGO
|S_IXUGO
,
75 static struct ctl_table_root sysctl_table_root
= {
76 .default_set
.dir
.header
= {
79 .ctl_table
= root_table
}},
80 .ctl_table_arg
= root_table
,
81 .root
= &sysctl_table_root
,
82 .set
= &sysctl_table_root
.default_set
,
86 static DEFINE_SPINLOCK(sysctl_lock
);
88 static void drop_sysctl_table(struct ctl_table_header
*header
);
89 static int sysctl_follow_link(struct ctl_table_header
**phead
,
90 struct ctl_table
**pentry
);
91 static int insert_links(struct ctl_table_header
*head
);
92 static void put_links(struct ctl_table_header
*header
);
94 static void sysctl_print_dir(struct ctl_dir
*dir
)
96 if (dir
->header
.parent
)
97 sysctl_print_dir(dir
->header
.parent
);
98 pr_cont("%s/", dir
->header
.ctl_table
[0].procname
);
101 static int namecmp(const char *name1
, int len1
, const char *name2
, int len2
)
105 cmp
= memcmp(name1
, name2
, min(len1
, len2
));
111 /* Called under sysctl_lock */
112 static struct ctl_table
*find_entry(struct ctl_table_header
**phead
,
113 struct ctl_dir
*dir
, const char *name
, int namelen
)
115 struct ctl_table_header
*head
;
116 struct ctl_table
*entry
;
117 struct rb_node
*node
= dir
->root
.rb_node
;
121 struct ctl_node
*ctl_node
;
122 const char *procname
;
125 ctl_node
= rb_entry(node
, struct ctl_node
, node
);
126 head
= ctl_node
->header
;
127 entry
= &head
->ctl_table
[ctl_node
- head
->node
];
128 procname
= entry
->procname
;
130 cmp
= namecmp(name
, namelen
, procname
, strlen(procname
));
132 node
= node
->rb_left
;
134 node
= node
->rb_right
;
143 static int insert_entry(struct ctl_table_header
*head
, struct ctl_table
*entry
)
145 struct rb_node
*node
= &head
->node
[entry
- head
->ctl_table
].node
;
146 struct rb_node
**p
= &head
->parent
->root
.rb_node
;
147 struct rb_node
*parent
= NULL
;
148 const char *name
= entry
->procname
;
149 int namelen
= strlen(name
);
152 struct ctl_table_header
*parent_head
;
153 struct ctl_table
*parent_entry
;
154 struct ctl_node
*parent_node
;
155 const char *parent_name
;
159 parent_node
= rb_entry(parent
, struct ctl_node
, node
);
160 parent_head
= parent_node
->header
;
161 parent_entry
= &parent_head
->ctl_table
[parent_node
- parent_head
->node
];
162 parent_name
= parent_entry
->procname
;
164 cmp
= namecmp(name
, namelen
, parent_name
, strlen(parent_name
));
170 pr_err("sysctl duplicate entry: ");
171 sysctl_print_dir(head
->parent
);
172 pr_cont("%s\n", entry
->procname
);
177 rb_link_node(node
, parent
, p
);
178 rb_insert_color(node
, &head
->parent
->root
);
182 static void erase_entry(struct ctl_table_header
*head
, struct ctl_table
*entry
)
184 struct rb_node
*node
= &head
->node
[entry
- head
->ctl_table
].node
;
186 rb_erase(node
, &head
->parent
->root
);
189 static void init_header(struct ctl_table_header
*head
,
190 struct ctl_table_root
*root
, struct ctl_table_set
*set
,
191 struct ctl_node
*node
, struct ctl_table
*table
)
193 head
->ctl_table
= table
;
194 head
->ctl_table_arg
= table
;
198 head
->unregistering
= NULL
;
203 INIT_HLIST_HEAD(&head
->inodes
);
205 struct ctl_table
*entry
;
207 list_for_each_table_entry(entry
, table
) {
214 static void erase_header(struct ctl_table_header
*head
)
216 struct ctl_table
*entry
;
218 list_for_each_table_entry(entry
, head
->ctl_table
)
219 erase_entry(head
, entry
);
222 static int insert_header(struct ctl_dir
*dir
, struct ctl_table_header
*header
)
224 struct ctl_table
*entry
;
225 struct ctl_table_header
*dir_h
= &dir
->header
;
229 /* Is this a permanently empty directory? */
230 if (sysctl_is_perm_empty_ctl_header(dir_h
))
233 /* Am I creating a permanently empty directory? */
234 if (sysctl_is_perm_empty_ctl_table(header
->ctl_table
)) {
235 if (!RB_EMPTY_ROOT(&dir
->root
))
237 sysctl_set_perm_empty_ctl_header(dir_h
);
241 header
->parent
= dir
;
242 err
= insert_links(header
);
245 list_for_each_table_entry(entry
, header
->ctl_table
) {
246 err
= insert_entry(header
, entry
);
252 erase_header(header
);
255 if (header
->ctl_table
== sysctl_mount_point
)
256 sysctl_clear_perm_empty_ctl_header(dir_h
);
257 header
->parent
= NULL
;
258 drop_sysctl_table(dir_h
);
262 /* called under sysctl_lock */
263 static int use_table(struct ctl_table_header
*p
)
265 if (unlikely(p
->unregistering
))
271 /* called under sysctl_lock */
272 static void unuse_table(struct ctl_table_header
*p
)
275 if (unlikely(p
->unregistering
))
276 complete(p
->unregistering
);
279 static void proc_sys_invalidate_dcache(struct ctl_table_header
*head
)
281 proc_invalidate_siblings_dcache(&head
->inodes
, &sysctl_lock
);
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 * Invalidate dentries for unregistered sysctls: namespaced sysctls
304 * can have duplicate names and contaminate dcache very badly.
306 proc_sys_invalidate_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
];
411 * sysctl_perm does NOT grant the superuser all rights automatically, because
412 * some sysctl variables are readonly even to root.
415 static int test_perm(int mode
, int op
)
417 if (uid_eq(current_euid(), GLOBAL_ROOT_UID
))
419 else if (in_egroup_p(GLOBAL_ROOT_GID
))
421 if ((op
& ~mode
& (MAY_READ
|MAY_WRITE
|MAY_EXEC
)) == 0)
426 static int sysctl_perm(struct ctl_table_header
*head
, struct ctl_table
*table
, int op
)
428 struct ctl_table_root
*root
= head
->root
;
431 if (root
->permissions
)
432 mode
= root
->permissions(head
, table
);
436 return test_perm(mode
, op
);
439 static struct inode
*proc_sys_make_inode(struct super_block
*sb
,
440 struct ctl_table_header
*head
, struct ctl_table
*table
)
442 struct ctl_table_root
*root
= head
->root
;
444 struct proc_inode
*ei
;
446 inode
= new_inode(sb
);
448 return ERR_PTR(-ENOMEM
);
450 inode
->i_ino
= get_next_ino();
454 spin_lock(&sysctl_lock
);
455 if (unlikely(head
->unregistering
)) {
456 spin_unlock(&sysctl_lock
);
458 return ERR_PTR(-ENOENT
);
461 ei
->sysctl_entry
= table
;
462 hlist_add_head_rcu(&ei
->sibling_inodes
, &head
->inodes
);
464 spin_unlock(&sysctl_lock
);
466 inode
->i_mtime
= inode
->i_atime
= inode
->i_ctime
= current_time(inode
);
467 inode
->i_mode
= table
->mode
;
468 if (!S_ISDIR(table
->mode
)) {
469 inode
->i_mode
|= S_IFREG
;
470 inode
->i_op
= &proc_sys_inode_operations
;
471 inode
->i_fop
= &proc_sys_file_operations
;
473 inode
->i_mode
|= S_IFDIR
;
474 inode
->i_op
= &proc_sys_dir_operations
;
475 inode
->i_fop
= &proc_sys_dir_file_operations
;
476 if (sysctl_is_perm_empty_ctl_header(head
))
477 make_empty_dir_inode(inode
);
480 if (root
->set_ownership
)
481 root
->set_ownership(head
, table
, &inode
->i_uid
, &inode
->i_gid
);
483 inode
->i_uid
= GLOBAL_ROOT_UID
;
484 inode
->i_gid
= GLOBAL_ROOT_GID
;
490 void proc_sys_evict_inode(struct inode
*inode
, struct ctl_table_header
*head
)
492 spin_lock(&sysctl_lock
);
493 hlist_del_init_rcu(&PROC_I(inode
)->sibling_inodes
);
495 kfree_rcu(head
, rcu
);
496 spin_unlock(&sysctl_lock
);
499 static struct ctl_table_header
*grab_header(struct inode
*inode
)
501 struct ctl_table_header
*head
= PROC_I(inode
)->sysctl
;
503 head
= &sysctl_table_root
.default_set
.dir
.header
;
504 return sysctl_head_grab(head
);
507 static struct dentry
*proc_sys_lookup(struct inode
*dir
, struct dentry
*dentry
,
510 struct ctl_table_header
*head
= grab_header(dir
);
511 struct ctl_table_header
*h
= NULL
;
512 const struct qstr
*name
= &dentry
->d_name
;
515 struct dentry
*err
= ERR_PTR(-ENOENT
);
516 struct ctl_dir
*ctl_dir
;
520 return ERR_CAST(head
);
522 ctl_dir
= container_of(head
, struct ctl_dir
, header
);
524 p
= lookup_entry(&h
, ctl_dir
, name
->name
, name
->len
);
528 if (S_ISLNK(p
->mode
)) {
529 ret
= sysctl_follow_link(&h
, &p
);
535 inode
= proc_sys_make_inode(dir
->i_sb
, h
? h
: head
, p
);
537 err
= ERR_CAST(inode
);
541 d_set_d_op(dentry
, &proc_sys_dentry_operations
);
542 err
= d_splice_alias(inode
, dentry
);
546 sysctl_head_finish(h
);
547 sysctl_head_finish(head
);
551 static ssize_t
proc_sys_call_handler(struct kiocb
*iocb
, struct iov_iter
*iter
,
554 struct inode
*inode
= file_inode(iocb
->ki_filp
);
555 struct ctl_table_header
*head
= grab_header(inode
);
556 struct ctl_table
*table
= PROC_I(inode
)->sysctl_entry
;
557 size_t count
= iov_iter_count(iter
);
562 return PTR_ERR(head
);
565 * At this point we know that the sysctl was not unregistered
566 * and won't be until we finish.
569 if (sysctl_perm(head
, table
, write
? MAY_WRITE
: MAY_READ
))
572 /* if that can happen at all, it should be -EINVAL, not -EISDIR */
574 if (!table
->proc_handler
)
577 /* don't even try if the size is too large */
579 if (count
>= KMALLOC_MAX_SIZE
)
581 kbuf
= kvzalloc(count
+ 1, GFP_KERNEL
);
587 if (!copy_from_iter_full(kbuf
, count
, iter
))
592 error
= BPF_CGROUP_RUN_PROG_SYSCTL(head
, table
, write
, &kbuf
, &count
,
597 /* careful: calling conventions are nasty here */
598 error
= table
->proc_handler(table
, write
, kbuf
, &count
, &iocb
->ki_pos
);
604 if (copy_to_iter(kbuf
, count
, iter
) < count
)
612 sysctl_head_finish(head
);
617 static ssize_t
proc_sys_read(struct kiocb
*iocb
, struct iov_iter
*iter
)
619 return proc_sys_call_handler(iocb
, iter
, 0);
622 static ssize_t
proc_sys_write(struct kiocb
*iocb
, struct iov_iter
*iter
)
624 return proc_sys_call_handler(iocb
, iter
, 1);
627 static int proc_sys_open(struct inode
*inode
, struct file
*filp
)
629 struct ctl_table_header
*head
= grab_header(inode
);
630 struct ctl_table
*table
= PROC_I(inode
)->sysctl_entry
;
632 /* sysctl was unregistered */
634 return PTR_ERR(head
);
637 filp
->private_data
= proc_sys_poll_event(table
->poll
);
639 sysctl_head_finish(head
);
644 static __poll_t
proc_sys_poll(struct file
*filp
, poll_table
*wait
)
646 struct inode
*inode
= file_inode(filp
);
647 struct ctl_table_header
*head
= grab_header(inode
);
648 struct ctl_table
*table
= PROC_I(inode
)->sysctl_entry
;
649 __poll_t ret
= DEFAULT_POLLMASK
;
652 /* sysctl was unregistered */
654 return EPOLLERR
| EPOLLHUP
;
656 if (!table
->proc_handler
)
662 event
= (unsigned long)filp
->private_data
;
663 poll_wait(filp
, &table
->poll
->wait
, wait
);
665 if (event
!= atomic_read(&table
->poll
->event
)) {
666 filp
->private_data
= proc_sys_poll_event(table
->poll
);
667 ret
= EPOLLIN
| EPOLLRDNORM
| EPOLLERR
| EPOLLPRI
;
671 sysctl_head_finish(head
);
676 static bool proc_sys_fill_cache(struct file
*file
,
677 struct dir_context
*ctx
,
678 struct ctl_table_header
*head
,
679 struct ctl_table
*table
)
681 struct dentry
*child
, *dir
= file
->f_path
.dentry
;
685 unsigned type
= DT_UNKNOWN
;
687 qname
.name
= table
->procname
;
688 qname
.len
= strlen(table
->procname
);
689 qname
.hash
= full_name_hash(dir
, qname
.name
, qname
.len
);
691 child
= d_lookup(dir
, &qname
);
693 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq
);
694 child
= d_alloc_parallel(dir
, &qname
, &wq
);
697 if (d_in_lookup(child
)) {
699 inode
= proc_sys_make_inode(dir
->d_sb
, head
, table
);
701 d_lookup_done(child
);
705 d_set_d_op(child
, &proc_sys_dentry_operations
);
706 res
= d_splice_alias(inode
, child
);
707 d_lookup_done(child
);
718 inode
= d_inode(child
);
720 type
= inode
->i_mode
>> 12;
722 return dir_emit(ctx
, qname
.name
, qname
.len
, ino
, type
);
725 static bool proc_sys_link_fill_cache(struct file
*file
,
726 struct dir_context
*ctx
,
727 struct ctl_table_header
*head
,
728 struct ctl_table
*table
)
732 head
= sysctl_head_grab(head
);
736 /* It is not an error if we can not follow the link ignore it */
737 if (sysctl_follow_link(&head
, &table
))
740 ret
= proc_sys_fill_cache(file
, ctx
, head
, table
);
742 sysctl_head_finish(head
);
746 static int scan(struct ctl_table_header
*head
, struct ctl_table
*table
,
747 unsigned long *pos
, struct file
*file
,
748 struct dir_context
*ctx
)
752 if ((*pos
)++ < ctx
->pos
)
755 if (unlikely(S_ISLNK(table
->mode
)))
756 res
= proc_sys_link_fill_cache(file
, ctx
, head
, table
);
758 res
= proc_sys_fill_cache(file
, ctx
, head
, table
);
766 static int proc_sys_readdir(struct file
*file
, struct dir_context
*ctx
)
768 struct ctl_table_header
*head
= grab_header(file_inode(file
));
769 struct ctl_table_header
*h
= NULL
;
770 struct ctl_table
*entry
;
771 struct ctl_dir
*ctl_dir
;
775 return PTR_ERR(head
);
777 ctl_dir
= container_of(head
, struct ctl_dir
, header
);
779 if (!dir_emit_dots(file
, ctx
))
784 for (first_entry(ctl_dir
, &h
, &entry
); h
; next_entry(&h
, &entry
)) {
785 if (!scan(h
, entry
, &pos
, file
, ctx
)) {
786 sysctl_head_finish(h
);
791 sysctl_head_finish(head
);
795 static int proc_sys_permission(struct mnt_idmap
*idmap
,
796 struct inode
*inode
, int mask
)
799 * sysctl entries that are not writeable,
800 * are _NOT_ writeable, capabilities or not.
802 struct ctl_table_header
*head
;
803 struct ctl_table
*table
;
806 /* Executable files are not allowed under /proc/sys/ */
807 if ((mask
& MAY_EXEC
) && S_ISREG(inode
->i_mode
))
810 head
= grab_header(inode
);
812 return PTR_ERR(head
);
814 table
= PROC_I(inode
)->sysctl_entry
;
815 if (!table
) /* global root - r-xr-xr-x */
816 error
= mask
& MAY_WRITE
? -EACCES
: 0;
817 else /* Use the permissions on the sysctl table entry */
818 error
= sysctl_perm(head
, table
, mask
& ~MAY_NOT_BLOCK
);
820 sysctl_head_finish(head
);
824 static int proc_sys_setattr(struct mnt_idmap
*idmap
,
825 struct dentry
*dentry
, struct iattr
*attr
)
827 struct inode
*inode
= d_inode(dentry
);
830 if (attr
->ia_valid
& (ATTR_MODE
| ATTR_UID
| ATTR_GID
))
833 error
= setattr_prepare(&nop_mnt_idmap
, dentry
, attr
);
837 setattr_copy(&nop_mnt_idmap
, inode
, attr
);
841 static int proc_sys_getattr(struct mnt_idmap
*idmap
,
842 const struct path
*path
, struct kstat
*stat
,
843 u32 request_mask
, unsigned int query_flags
)
845 struct inode
*inode
= d_inode(path
->dentry
);
846 struct ctl_table_header
*head
= grab_header(inode
);
847 struct ctl_table
*table
= PROC_I(inode
)->sysctl_entry
;
850 return PTR_ERR(head
);
852 generic_fillattr(&nop_mnt_idmap
, inode
, stat
);
854 stat
->mode
= (stat
->mode
& S_IFMT
) | table
->mode
;
856 sysctl_head_finish(head
);
860 static const struct file_operations proc_sys_file_operations
= {
861 .open
= proc_sys_open
,
862 .poll
= proc_sys_poll
,
863 .read_iter
= proc_sys_read
,
864 .write_iter
= proc_sys_write
,
865 .splice_read
= copy_splice_read
,
866 .splice_write
= iter_file_splice_write
,
867 .llseek
= default_llseek
,
870 static const struct file_operations proc_sys_dir_file_operations
= {
871 .read
= generic_read_dir
,
872 .iterate_shared
= proc_sys_readdir
,
873 .llseek
= generic_file_llseek
,
876 static const struct inode_operations proc_sys_inode_operations
= {
877 .permission
= proc_sys_permission
,
878 .setattr
= proc_sys_setattr
,
879 .getattr
= proc_sys_getattr
,
882 static const struct inode_operations proc_sys_dir_operations
= {
883 .lookup
= proc_sys_lookup
,
884 .permission
= proc_sys_permission
,
885 .setattr
= proc_sys_setattr
,
886 .getattr
= proc_sys_getattr
,
889 static int proc_sys_revalidate(struct dentry
*dentry
, unsigned int flags
)
891 if (flags
& LOOKUP_RCU
)
893 return !PROC_I(d_inode(dentry
))->sysctl
->unregistering
;
896 static int proc_sys_delete(const struct dentry
*dentry
)
898 return !!PROC_I(d_inode(dentry
))->sysctl
->unregistering
;
901 static int sysctl_is_seen(struct ctl_table_header
*p
)
903 struct ctl_table_set
*set
= p
->set
;
905 spin_lock(&sysctl_lock
);
906 if (p
->unregistering
)
908 else if (!set
->is_seen
)
911 res
= set
->is_seen(set
);
912 spin_unlock(&sysctl_lock
);
916 static int proc_sys_compare(const struct dentry
*dentry
,
917 unsigned int len
, const char *str
, const struct qstr
*name
)
919 struct ctl_table_header
*head
;
922 /* Although proc doesn't have negative dentries, rcu-walk means
923 * that inode here can be NULL */
924 /* AV: can it, indeed? */
925 inode
= d_inode_rcu(dentry
);
928 if (name
->len
!= len
)
930 if (memcmp(name
->name
, str
, len
))
932 head
= rcu_dereference(PROC_I(inode
)->sysctl
);
933 return !head
|| !sysctl_is_seen(head
);
936 static const struct dentry_operations proc_sys_dentry_operations
= {
937 .d_revalidate
= proc_sys_revalidate
,
938 .d_delete
= proc_sys_delete
,
939 .d_compare
= proc_sys_compare
,
942 static struct ctl_dir
*find_subdir(struct ctl_dir
*dir
,
943 const char *name
, int namelen
)
945 struct ctl_table_header
*head
;
946 struct ctl_table
*entry
;
948 entry
= find_entry(&head
, dir
, name
, namelen
);
950 return ERR_PTR(-ENOENT
);
951 if (!S_ISDIR(entry
->mode
))
952 return ERR_PTR(-ENOTDIR
);
953 return container_of(head
, struct ctl_dir
, header
);
956 static struct ctl_dir
*new_dir(struct ctl_table_set
*set
,
957 const char *name
, int namelen
)
959 struct ctl_table
*table
;
961 struct ctl_node
*node
;
964 new = kzalloc(sizeof(*new) + sizeof(struct ctl_node
) +
965 sizeof(struct ctl_table
)*2 + namelen
+ 1,
970 node
= (struct ctl_node
*)(new + 1);
971 table
= (struct ctl_table
*)(node
+ 1);
972 new_name
= (char *)(table
+ 2);
973 memcpy(new_name
, name
, namelen
);
974 table
[0].procname
= new_name
;
975 table
[0].mode
= S_IFDIR
|S_IRUGO
|S_IXUGO
;
976 init_header(&new->header
, set
->dir
.header
.root
, set
, node
, table
);
982 * get_subdir - find or create a subdir with the specified name.
983 * @dir: Directory to create the subdirectory in
984 * @name: The name of the subdirectory to find or create
985 * @namelen: The length of name
987 * Takes a directory with an elevated reference count so we know that
988 * if we drop the lock the directory will not go away. Upon success
989 * the reference is moved from @dir to the returned subdirectory.
990 * Upon error an error code is returned and the reference on @dir is
993 static struct ctl_dir
*get_subdir(struct ctl_dir
*dir
,
994 const char *name
, int namelen
)
996 struct ctl_table_set
*set
= dir
->header
.set
;
997 struct ctl_dir
*subdir
, *new = NULL
;
1000 spin_lock(&sysctl_lock
);
1001 subdir
= find_subdir(dir
, name
, namelen
);
1002 if (!IS_ERR(subdir
))
1004 if (PTR_ERR(subdir
) != -ENOENT
)
1007 spin_unlock(&sysctl_lock
);
1008 new = new_dir(set
, name
, namelen
);
1009 spin_lock(&sysctl_lock
);
1010 subdir
= ERR_PTR(-ENOMEM
);
1014 /* Was the subdir added while we dropped the lock? */
1015 subdir
= find_subdir(dir
, name
, namelen
);
1016 if (!IS_ERR(subdir
))
1018 if (PTR_ERR(subdir
) != -ENOENT
)
1021 /* Nope. Use the our freshly made directory entry. */
1022 err
= insert_header(dir
, &new->header
);
1023 subdir
= ERR_PTR(err
);
1028 subdir
->header
.nreg
++;
1030 if (IS_ERR(subdir
)) {
1031 pr_err("sysctl could not get directory: ");
1032 sysctl_print_dir(dir
);
1033 pr_cont("%*.*s %ld\n", namelen
, namelen
, name
,
1036 drop_sysctl_table(&dir
->header
);
1038 drop_sysctl_table(&new->header
);
1039 spin_unlock(&sysctl_lock
);
1043 static struct ctl_dir
*xlate_dir(struct ctl_table_set
*set
, struct ctl_dir
*dir
)
1045 struct ctl_dir
*parent
;
1046 const char *procname
;
1047 if (!dir
->header
.parent
)
1049 parent
= xlate_dir(set
, dir
->header
.parent
);
1052 procname
= dir
->header
.ctl_table
[0].procname
;
1053 return find_subdir(parent
, procname
, strlen(procname
));
1056 static int sysctl_follow_link(struct ctl_table_header
**phead
,
1057 struct ctl_table
**pentry
)
1059 struct ctl_table_header
*head
;
1060 struct ctl_table_root
*root
;
1061 struct ctl_table_set
*set
;
1062 struct ctl_table
*entry
;
1063 struct ctl_dir
*dir
;
1066 spin_lock(&sysctl_lock
);
1067 root
= (*pentry
)->data
;
1068 set
= lookup_header_set(root
);
1069 dir
= xlate_dir(set
, (*phead
)->parent
);
1073 const char *procname
= (*pentry
)->procname
;
1075 entry
= find_entry(&head
, dir
, procname
, strlen(procname
));
1077 if (entry
&& use_table(head
)) {
1078 unuse_table(*phead
);
1085 spin_unlock(&sysctl_lock
);
1089 static int sysctl_err(const char *path
, struct ctl_table
*table
, char *fmt
, ...)
1091 struct va_format vaf
;
1094 va_start(args
, fmt
);
1098 pr_err("sysctl table check failed: %s/%s %pV\n",
1099 path
, table
->procname
, &vaf
);
1105 static int sysctl_check_table_array(const char *path
, struct ctl_table
*table
)
1109 if ((table
->proc_handler
== proc_douintvec
) ||
1110 (table
->proc_handler
== proc_douintvec_minmax
)) {
1111 if (table
->maxlen
!= sizeof(unsigned int))
1112 err
|= sysctl_err(path
, table
, "array not allowed");
1115 if (table
->proc_handler
== proc_dou8vec_minmax
) {
1116 if (table
->maxlen
!= sizeof(u8
))
1117 err
|= sysctl_err(path
, table
, "array not allowed");
1120 if (table
->proc_handler
== proc_dobool
) {
1121 if (table
->maxlen
!= sizeof(bool))
1122 err
|= sysctl_err(path
, table
, "array not allowed");
1128 static int sysctl_check_table(const char *path
, struct ctl_table
*table
)
1130 struct ctl_table
*entry
;
1132 list_for_each_table_entry(entry
, table
) {
1133 if ((entry
->proc_handler
== proc_dostring
) ||
1134 (entry
->proc_handler
== proc_dobool
) ||
1135 (entry
->proc_handler
== proc_dointvec
) ||
1136 (entry
->proc_handler
== proc_douintvec
) ||
1137 (entry
->proc_handler
== proc_douintvec_minmax
) ||
1138 (entry
->proc_handler
== proc_dointvec_minmax
) ||
1139 (entry
->proc_handler
== proc_dou8vec_minmax
) ||
1140 (entry
->proc_handler
== proc_dointvec_jiffies
) ||
1141 (entry
->proc_handler
== proc_dointvec_userhz_jiffies
) ||
1142 (entry
->proc_handler
== proc_dointvec_ms_jiffies
) ||
1143 (entry
->proc_handler
== proc_doulongvec_minmax
) ||
1144 (entry
->proc_handler
== proc_doulongvec_ms_jiffies_minmax
)) {
1146 err
|= sysctl_err(path
, entry
, "No data");
1148 err
|= sysctl_err(path
, entry
, "No maxlen");
1150 err
|= sysctl_check_table_array(path
, entry
);
1152 if (!entry
->proc_handler
)
1153 err
|= sysctl_err(path
, entry
, "No proc_handler");
1155 if ((entry
->mode
& (S_IRUGO
|S_IWUGO
)) != entry
->mode
)
1156 err
|= sysctl_err(path
, entry
, "bogus .mode 0%o",
1162 static struct ctl_table_header
*new_links(struct ctl_dir
*dir
, struct ctl_table
*table
,
1163 struct ctl_table_root
*link_root
)
1165 struct ctl_table
*link_table
, *entry
, *link
;
1166 struct ctl_table_header
*links
;
1167 struct ctl_node
*node
;
1169 int nr_entries
, name_bytes
;
1173 list_for_each_table_entry(entry
, table
) {
1175 name_bytes
+= strlen(entry
->procname
) + 1;
1178 links
= kzalloc(sizeof(struct ctl_table_header
) +
1179 sizeof(struct ctl_node
)*nr_entries
+
1180 sizeof(struct ctl_table
)*(nr_entries
+ 1) +
1187 node
= (struct ctl_node
*)(links
+ 1);
1188 link_table
= (struct ctl_table
*)(node
+ nr_entries
);
1189 link_name
= (char *)&link_table
[nr_entries
+ 1];
1192 list_for_each_table_entry(entry
, table
) {
1193 int len
= strlen(entry
->procname
) + 1;
1194 memcpy(link_name
, entry
->procname
, len
);
1195 link
->procname
= link_name
;
1196 link
->mode
= S_IFLNK
|S_IRWXUGO
;
1197 link
->data
= link_root
;
1201 init_header(links
, dir
->header
.root
, dir
->header
.set
, node
, link_table
);
1202 links
->nreg
= nr_entries
;
1207 static bool get_links(struct ctl_dir
*dir
,
1208 struct ctl_table
*table
, struct ctl_table_root
*link_root
)
1210 struct ctl_table_header
*head
;
1211 struct ctl_table
*entry
, *link
;
1213 /* Are there links available for every entry in table? */
1214 list_for_each_table_entry(entry
, table
) {
1215 const char *procname
= entry
->procname
;
1216 link
= find_entry(&head
, dir
, procname
, strlen(procname
));
1219 if (S_ISDIR(link
->mode
) && S_ISDIR(entry
->mode
))
1221 if (S_ISLNK(link
->mode
) && (link
->data
== link_root
))
1226 /* The checks passed. Increase the registration count on the links */
1227 list_for_each_table_entry(entry
, table
) {
1228 const char *procname
= entry
->procname
;
1229 link
= find_entry(&head
, dir
, procname
, strlen(procname
));
1235 static int insert_links(struct ctl_table_header
*head
)
1237 struct ctl_table_set
*root_set
= &sysctl_table_root
.default_set
;
1238 struct ctl_dir
*core_parent
;
1239 struct ctl_table_header
*links
;
1242 if (head
->set
== root_set
)
1245 core_parent
= xlate_dir(root_set
, head
->parent
);
1246 if (IS_ERR(core_parent
))
1249 if (get_links(core_parent
, head
->ctl_table
, head
->root
))
1252 core_parent
->header
.nreg
++;
1253 spin_unlock(&sysctl_lock
);
1255 links
= new_links(core_parent
, head
->ctl_table
, head
->root
);
1257 spin_lock(&sysctl_lock
);
1263 if (get_links(core_parent
, head
->ctl_table
, head
->root
)) {
1268 err
= insert_header(core_parent
, links
);
1272 drop_sysctl_table(&core_parent
->header
);
1276 /* Find the directory for the ctl_table. If one is not found create it. */
1277 static struct ctl_dir
*sysctl_mkdir_p(struct ctl_dir
*dir
, const char *path
)
1279 const char *name
, *nextname
;
1281 for (name
= path
; name
; name
= nextname
) {
1283 nextname
= strchr(name
, '/');
1285 namelen
= nextname
- name
;
1288 namelen
= strlen(name
);
1294 * namelen ensures if name is "foo/bar/yay" only foo is
1295 * registered first. We traverse as if using mkdir -p and
1296 * return a ctl_dir for the last directory entry.
1298 dir
= get_subdir(dir
, name
, namelen
);
1306 * __register_sysctl_table - register a leaf sysctl table
1307 * @set: Sysctl tree to register on
1308 * @path: The path to the directory the sysctl table is in.
1309 * @table: the top-level table structure without any child. This table
1310 * should not be free'd after registration. So it should not be
1311 * used on stack. It can either be a global or dynamically allocated
1312 * by the caller and free'd later after sysctl unregistration.
1314 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1315 * array. A completely 0 filled entry terminates the table.
1317 * The members of the &struct ctl_table structure are used as follows:
1319 * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
1320 * enter a sysctl file
1322 * data - a pointer to data for use by proc_handler
1324 * maxlen - the maximum size in bytes of the data
1326 * mode - the file permissions for the /proc/sys file
1328 * child - must be %NULL.
1330 * proc_handler - the text handler routine (described below)
1332 * extra1, extra2 - extra pointers usable by the proc handler routines
1333 * XXX: we should eventually modify these to use long min / max [0]
1334 * [0] https://lkml.kernel.org/87zgpte9o4.fsf@email.froward.int.ebiederm.org
1336 * Leaf nodes in the sysctl tree will be represented by a single file
1337 * under /proc; non-leaf nodes (where child is not NULL) are not allowed,
1338 * sysctl_check_table() verifies this.
1340 * There must be a proc_handler routine for any terminal nodes.
1341 * Several default handlers are available to cover common cases -
1343 * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
1344 * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
1345 * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
1347 * It is the handler's job to read the input buffer from user memory
1348 * and process it. The handler should return 0 on success.
1350 * This routine returns %NULL on a failure to register, and a pointer
1351 * to the table header on success.
1353 struct ctl_table_header
*__register_sysctl_table(
1354 struct ctl_table_set
*set
,
1355 const char *path
, struct ctl_table
*table
)
1357 struct ctl_table_root
*root
= set
->dir
.header
.root
;
1358 struct ctl_table_header
*header
;
1359 struct ctl_dir
*dir
;
1360 struct ctl_table
*entry
;
1361 struct ctl_node
*node
;
1364 list_for_each_table_entry(entry
, table
)
1367 header
= kzalloc(sizeof(struct ctl_table_header
) +
1368 sizeof(struct ctl_node
)*nr_entries
, GFP_KERNEL_ACCOUNT
);
1372 node
= (struct ctl_node
*)(header
+ 1);
1373 init_header(header
, root
, set
, node
, table
);
1374 if (sysctl_check_table(path
, table
))
1377 spin_lock(&sysctl_lock
);
1379 /* Reference moved down the directory tree get_subdir */
1381 spin_unlock(&sysctl_lock
);
1383 dir
= sysctl_mkdir_p(dir
, path
);
1386 spin_lock(&sysctl_lock
);
1387 if (insert_header(dir
, header
))
1388 goto fail_put_dir_locked
;
1390 drop_sysctl_table(&dir
->header
);
1391 spin_unlock(&sysctl_lock
);
1395 fail_put_dir_locked
:
1396 drop_sysctl_table(&dir
->header
);
1397 spin_unlock(&sysctl_lock
);
1404 * register_sysctl - register a sysctl table
1405 * @path: The path to the directory the sysctl table is in. If the path
1406 * doesn't exist we will create it for you.
1407 * @table: the table structure. The calller must ensure the life of the @table
1408 * will be kept during the lifetime use of the syctl. It must not be freed
1409 * until unregister_sysctl_table() is called with the given returned table
1410 * with this registration. If your code is non modular then you don't need
1411 * to call unregister_sysctl_table() and can instead use something like
1412 * register_sysctl_init() which does not care for the result of the syctl
1415 * Register a sysctl table. @table should be a filled in ctl_table
1416 * array. A completely 0 filled entry terminates the table.
1418 * See __register_sysctl_table for more details.
1420 struct ctl_table_header
*register_sysctl(const char *path
, struct ctl_table
*table
)
1422 return __register_sysctl_table(&sysctl_table_root
.default_set
,
1425 EXPORT_SYMBOL(register_sysctl
);
1428 * __register_sysctl_init() - register sysctl table to path
1429 * @path: path name for sysctl base. If that path doesn't exist we will create
1431 * @table: This is the sysctl table that needs to be registered to the path.
1432 * The caller must ensure the life of the @table will be kept during the
1433 * lifetime use of the sysctl.
1434 * @table_name: The name of sysctl table, only used for log printing when
1435 * registration fails
1437 * The sysctl interface is used by userspace to query or modify at runtime
1438 * a predefined value set on a variable. These variables however have default
1439 * values pre-set. Code which depends on these variables will always work even
1440 * if register_sysctl() fails. If register_sysctl() fails you'd just loose the
1441 * ability to query or modify the sysctls dynamically at run time. Chances of
1442 * register_sysctl() failing on init are extremely low, and so for both reasons
1443 * this function does not return any error as it is used by initialization code.
1445 * Context: if your base directory does not exist it will be created for you.
1447 void __init
__register_sysctl_init(const char *path
, struct ctl_table
*table
,
1448 const char *table_name
)
1450 struct ctl_table_header
*hdr
= register_sysctl(path
, table
);
1452 if (unlikely(!hdr
)) {
1453 pr_err("failed when register_sysctl %s to %s\n", table_name
, path
);
1456 kmemleak_not_leak(hdr
);
1459 static void put_links(struct ctl_table_header
*header
)
1461 struct ctl_table_set
*root_set
= &sysctl_table_root
.default_set
;
1462 struct ctl_table_root
*root
= header
->root
;
1463 struct ctl_dir
*parent
= header
->parent
;
1464 struct ctl_dir
*core_parent
;
1465 struct ctl_table
*entry
;
1467 if (header
->set
== root_set
)
1470 core_parent
= xlate_dir(root_set
, parent
);
1471 if (IS_ERR(core_parent
))
1474 list_for_each_table_entry(entry
, header
->ctl_table
) {
1475 struct ctl_table_header
*link_head
;
1476 struct ctl_table
*link
;
1477 const char *name
= entry
->procname
;
1479 link
= find_entry(&link_head
, core_parent
, name
, strlen(name
));
1481 ((S_ISDIR(link
->mode
) && S_ISDIR(entry
->mode
)) ||
1482 (S_ISLNK(link
->mode
) && (link
->data
== root
)))) {
1483 drop_sysctl_table(link_head
);
1486 pr_err("sysctl link missing during unregister: ");
1487 sysctl_print_dir(parent
);
1488 pr_cont("%s\n", name
);
1493 static void drop_sysctl_table(struct ctl_table_header
*header
)
1495 struct ctl_dir
*parent
= header
->parent
;
1502 start_unregistering(header
);
1505 if (!--header
->count
)
1506 kfree_rcu(header
, rcu
);
1509 drop_sysctl_table(&parent
->header
);
1513 * unregister_sysctl_table - unregister a sysctl table hierarchy
1514 * @header: the header returned from register_sysctl or __register_sysctl_table
1516 * Unregisters the sysctl table and all children. proc entries may not
1517 * actually be removed until they are no longer used by anyone.
1519 void unregister_sysctl_table(struct ctl_table_header
* header
)
1526 spin_lock(&sysctl_lock
);
1527 drop_sysctl_table(header
);
1528 spin_unlock(&sysctl_lock
);
1530 EXPORT_SYMBOL(unregister_sysctl_table
);
1532 void setup_sysctl_set(struct ctl_table_set
*set
,
1533 struct ctl_table_root
*root
,
1534 int (*is_seen
)(struct ctl_table_set
*))
1536 memset(set
, 0, sizeof(*set
));
1537 set
->is_seen
= is_seen
;
1538 init_header(&set
->dir
.header
, root
, set
, NULL
, root_table
);
1541 void retire_sysctl_set(struct ctl_table_set
*set
)
1543 WARN_ON(!RB_EMPTY_ROOT(&set
->dir
.root
));
1546 int __init
proc_sys_init(void)
1548 struct proc_dir_entry
*proc_sys_root
;
1550 proc_sys_root
= proc_mkdir("sys", NULL
);
1551 proc_sys_root
->proc_iops
= &proc_sys_dir_operations
;
1552 proc_sys_root
->proc_dir_ops
= &proc_sys_dir_file_operations
;
1553 proc_sys_root
->nlink
= 0;
1555 return sysctl_init_bases();
1558 struct sysctl_alias
{
1559 const char *kernel_param
;
1560 const char *sysctl_param
;
1564 * Historically some settings had both sysctl and a command line parameter.
1565 * With the generic sysctl. parameter support, we can handle them at a single
1566 * place and only keep the historical name for compatibility. This is not meant
1567 * to add brand new aliases. When adding existing aliases, consider whether
1568 * the possibly different moment of changing the value (e.g. from early_param
1569 * to the moment do_sysctl_args() is called) is an issue for the specific
1572 static const struct sysctl_alias sysctl_aliases
[] = {
1573 {"hardlockup_all_cpu_backtrace", "kernel.hardlockup_all_cpu_backtrace" },
1574 {"hung_task_panic", "kernel.hung_task_panic" },
1575 {"numa_zonelist_order", "vm.numa_zonelist_order" },
1576 {"softlockup_all_cpu_backtrace", "kernel.softlockup_all_cpu_backtrace" },
1577 {"softlockup_panic", "kernel.softlockup_panic" },
1581 static const char *sysctl_find_alias(char *param
)
1583 const struct sysctl_alias
*alias
;
1585 for (alias
= &sysctl_aliases
[0]; alias
->kernel_param
!= NULL
; alias
++) {
1586 if (strcmp(alias
->kernel_param
, param
) == 0)
1587 return alias
->sysctl_param
;
1593 /* Set sysctl value passed on kernel command line. */
1594 static int process_sysctl_arg(char *param
, char *val
,
1595 const char *unused
, void *arg
)
1598 struct vfsmount
**proc_mnt
= arg
;
1599 struct file_system_type
*proc_fs_type
;
1606 if (strncmp(param
, "sysctl", sizeof("sysctl") - 1) == 0) {
1607 param
+= sizeof("sysctl") - 1;
1609 if (param
[0] != '/' && param
[0] != '.')
1614 param
= (char *) sysctl_find_alias(param
);
1626 * To set sysctl options, we use a temporary mount of proc, look up the
1627 * respective sys/ file and write to it. To avoid mounting it when no
1628 * options were given, we mount it only when the first sysctl option is
1629 * found. Why not a persistent mount? There are problems with a
1630 * persistent mount of proc in that it forces userspace not to use any
1631 * proc mount options.
1634 proc_fs_type
= get_fs_type("proc");
1635 if (!proc_fs_type
) {
1636 pr_err("Failed to find procfs to set sysctl from command line\n");
1639 *proc_mnt
= kern_mount(proc_fs_type
);
1640 put_filesystem(proc_fs_type
);
1641 if (IS_ERR(*proc_mnt
)) {
1642 pr_err("Failed to mount procfs to set sysctl from command line\n");
1647 path
= kasprintf(GFP_KERNEL
, "sys/%s", param
);
1649 panic("%s: Failed to allocate path for %s\n", __func__
, param
);
1650 strreplace(path
, '.', '/');
1652 file
= file_open_root_mnt(*proc_mnt
, path
, O_WRONLY
, 0);
1654 err
= PTR_ERR(file
);
1656 pr_err("Failed to set sysctl parameter '%s=%s': parameter not found\n",
1658 else if (err
== -EACCES
)
1659 pr_err("Failed to set sysctl parameter '%s=%s': permission denied (read-only?)\n",
1662 pr_err("Error %pe opening proc file to set sysctl parameter '%s=%s'\n",
1666 wret
= kernel_write(file
, val
, len
, &pos
);
1670 pr_err("Failed to set sysctl parameter '%s=%s': invalid value\n",
1673 pr_err("Error %pe writing to proc file to set sysctl parameter '%s=%s'\n",
1674 ERR_PTR(err
), param
, val
);
1675 } else if (wret
!= len
) {
1676 pr_err("Wrote only %zd bytes of %d writing to proc file %s to set sysctl parameter '%s=%s\n",
1677 wret
, len
, path
, param
, val
);
1680 err
= filp_close(file
, NULL
);
1682 pr_err("Error %pe closing proc file to set sysctl parameter '%s=%s\n",
1683 ERR_PTR(err
), param
, val
);
1689 void do_sysctl_args(void)
1692 struct vfsmount
*proc_mnt
= NULL
;
1694 command_line
= kstrdup(saved_command_line
, GFP_KERNEL
);
1696 panic("%s: Failed to allocate copy of command line\n", __func__
);
1698 parse_args("Setting sysctl args", command_line
,
1699 NULL
, 0, -1, -1, &proc_mnt
, process_sysctl_arg
);
1702 kern_unmount(proc_mnt
);
1704 kfree(command_line
);