4 #include <linux/init.h>
5 #include <linux/sysctl.h>
6 #include <linux/poll.h>
7 #include <linux/proc_fs.h>
8 #include <linux/security.h>
9 #include <linux/namei.h>
10 #include <linux/module.h>
13 static const struct dentry_operations proc_sys_dentry_operations;
14 static const struct file_operations proc_sys_file_operations;
15 static const struct inode_operations proc_sys_inode_operations;
16 static const struct file_operations proc_sys_dir_file_operations;
17 static const struct inode_operations proc_sys_dir_operations;
19 void proc_sys_poll_notify(struct ctl_table_poll *poll)
24 atomic_inc(&poll->event);
25 wake_up_interruptible(&poll->wait);
28 static struct ctl_table root_table[1];
29 static struct ctl_table_root sysctl_table_root;
30 static struct ctl_table_header root_table_header = {
32 .ctl_table = root_table,
33 .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}},
34 .root = &sysctl_table_root,
35 .set = &sysctl_table_root.default_set,
37 static struct ctl_table_root sysctl_table_root = {
38 .root_list = LIST_HEAD_INIT(sysctl_table_root.root_list),
39 .default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry),
42 static DEFINE_SPINLOCK(sysctl_lock);
44 /* called under sysctl_lock */
45 static int use_table(struct ctl_table_header *p)
47 if (unlikely(p->unregistering))
53 /* called under sysctl_lock */
54 static void unuse_table(struct ctl_table_header *p)
57 if (unlikely(p->unregistering))
58 complete(p->unregistering);
61 /* called under sysctl_lock, will reacquire if has to wait */
62 static void start_unregistering(struct ctl_table_header *p)
65 * if p->used is 0, nobody will ever touch that entry again;
66 * we'll eliminate all paths to it before dropping sysctl_lock
68 if (unlikely(p->used)) {
69 struct completion wait;
70 init_completion(&wait);
71 p->unregistering = &wait;
72 spin_unlock(&sysctl_lock);
73 wait_for_completion(&wait);
74 spin_lock(&sysctl_lock);
76 /* anything non-NULL; we'll never dereference it */
77 p->unregistering = ERR_PTR(-EINVAL);
80 * do not remove from the list until nobody holds it; walking the
81 * list in do_sysctl() relies on that.
83 list_del_init(&p->ctl_entry);
86 static void sysctl_head_get(struct ctl_table_header *head)
88 spin_lock(&sysctl_lock);
90 spin_unlock(&sysctl_lock);
93 void sysctl_head_put(struct ctl_table_header *head)
95 spin_lock(&sysctl_lock);
98 spin_unlock(&sysctl_lock);
101 static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
105 spin_lock(&sysctl_lock);
106 if (!use_table(head))
107 head = ERR_PTR(-ENOENT);
108 spin_unlock(&sysctl_lock);
112 static void sysctl_head_finish(struct ctl_table_header *head)
116 spin_lock(&sysctl_lock);
118 spin_unlock(&sysctl_lock);
121 static struct ctl_table_set *
122 lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces)
124 struct ctl_table_set *set = &root->default_set;
126 set = root->lookup(root, namespaces);
130 static struct list_head *
131 lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces)
133 struct ctl_table_set *set = lookup_header_set(root, namespaces);
137 static struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
138 struct ctl_table_header *prev)
140 struct ctl_table_root *root;
141 struct list_head *header_list;
142 struct ctl_table_header *head;
143 struct list_head *tmp;
145 spin_lock(&sysctl_lock);
148 tmp = &prev->ctl_entry;
152 tmp = &root_table_header.ctl_entry;
154 head = list_entry(tmp, struct ctl_table_header, ctl_entry);
156 if (!use_table(head))
158 spin_unlock(&sysctl_lock);
163 header_list = lookup_header_list(root, namespaces);
164 if (tmp != header_list)
168 root = list_entry(root->root_list.next,
169 struct ctl_table_root, root_list);
170 if (root == &sysctl_table_root)
172 header_list = lookup_header_list(root, namespaces);
173 } while (list_empty(header_list));
174 tmp = header_list->next;
177 spin_unlock(&sysctl_lock);
181 static struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev)
183 return __sysctl_head_next(current->nsproxy, prev);
186 void register_sysctl_root(struct ctl_table_root *root)
188 spin_lock(&sysctl_lock);
189 list_add_tail(&root->root_list, &sysctl_table_root.root_list);
190 spin_unlock(&sysctl_lock);
194 * sysctl_perm does NOT grant the superuser all rights automatically, because
195 * some sysctl variables are readonly even to root.
198 static int test_perm(int mode, int op)
202 else if (in_egroup_p(0))
204 if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
209 static int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op)
213 if (root->permissions)
214 mode = root->permissions(root, current->nsproxy, table);
218 return test_perm(mode, op);
221 static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
223 for (; table->procname; table++) {
224 table->parent = parent;
226 sysctl_set_parent(table, table->child);
231 static struct inode *proc_sys_make_inode(struct super_block *sb,
232 struct ctl_table_header *head, struct ctl_table *table)
235 struct proc_inode *ei;
237 inode = new_inode(sb);
241 inode->i_ino = get_next_ino();
243 sysctl_head_get(head);
246 ei->sysctl_entry = table;
248 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
249 inode->i_mode = table->mode;
251 inode->i_mode |= S_IFREG;
252 inode->i_op = &proc_sys_inode_operations;
253 inode->i_fop = &proc_sys_file_operations;
255 inode->i_mode |= S_IFDIR;
256 inode->i_op = &proc_sys_dir_operations;
257 inode->i_fop = &proc_sys_dir_file_operations;
263 static struct ctl_table *find_in_table(struct ctl_table *p, struct qstr *name)
265 for ( ; p->procname; p++) {
266 if (strlen(p->procname) != name->len)
269 if (memcmp(p->procname, name->name, name->len) != 0)
278 static struct ctl_table_header *grab_header(struct inode *inode)
280 if (PROC_I(inode)->sysctl)
281 return sysctl_head_grab(PROC_I(inode)->sysctl);
283 return sysctl_head_next(NULL);
286 static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
287 struct nameidata *nd)
289 struct ctl_table_header *head = grab_header(dir);
290 struct ctl_table *table = PROC_I(dir)->sysctl_entry;
291 struct ctl_table_header *h = NULL;
292 struct qstr *name = &dentry->d_name;
295 struct dentry *err = ERR_PTR(-ENOENT);
298 return ERR_CAST(head);
300 if (table && !table->child) {
305 table = table ? table->child : head->ctl_table;
307 p = find_in_table(table, name);
309 for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
310 if (h->attached_to != table)
312 p = find_in_table(h->attached_by, name);
321 err = ERR_PTR(-ENOMEM);
322 inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
324 sysctl_head_finish(h);
330 d_set_d_op(dentry, &proc_sys_dentry_operations);
331 d_add(dentry, inode);
334 sysctl_head_finish(head);
338 static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,
339 size_t count, loff_t *ppos, int write)
341 struct inode *inode = filp->f_path.dentry->d_inode;
342 struct ctl_table_header *head = grab_header(inode);
343 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
348 return PTR_ERR(head);
351 * At this point we know that the sysctl was not unregistered
352 * and won't be until we finish.
355 if (sysctl_perm(head->root, table, write ? MAY_WRITE : MAY_READ))
358 /* if that can happen at all, it should be -EINVAL, not -EISDIR */
360 if (!table->proc_handler)
363 /* careful: calling conventions are nasty here */
365 error = table->proc_handler(table, write, buf, &res, ppos);
369 sysctl_head_finish(head);
374 static ssize_t proc_sys_read(struct file *filp, char __user *buf,
375 size_t count, loff_t *ppos)
377 return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0);
380 static ssize_t proc_sys_write(struct file *filp, const char __user *buf,
381 size_t count, loff_t *ppos)
383 return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1);
386 static int proc_sys_open(struct inode *inode, struct file *filp)
388 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
391 filp->private_data = proc_sys_poll_event(table->poll);
396 static unsigned int proc_sys_poll(struct file *filp, poll_table *wait)
398 struct inode *inode = filp->f_path.dentry->d_inode;
399 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
400 unsigned long event = (unsigned long)filp->private_data;
401 unsigned int ret = DEFAULT_POLLMASK;
403 if (!table->proc_handler)
409 poll_wait(filp, &table->poll->wait, wait);
411 if (event != atomic_read(&table->poll->event)) {
412 filp->private_data = proc_sys_poll_event(table->poll);
413 ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI;
420 static int proc_sys_fill_cache(struct file *filp, void *dirent,
422 struct ctl_table_header *head,
423 struct ctl_table *table)
425 struct dentry *child, *dir = filp->f_path.dentry;
429 unsigned type = DT_UNKNOWN;
431 qname.name = table->procname;
432 qname.len = strlen(table->procname);
433 qname.hash = full_name_hash(qname.name, qname.len);
435 child = d_lookup(dir, &qname);
437 child = d_alloc(dir, &qname);
439 inode = proc_sys_make_inode(dir->d_sb, head, table);
444 d_set_d_op(child, &proc_sys_dentry_operations);
451 inode = child->d_inode;
453 type = inode->i_mode >> 12;
455 return !!filldir(dirent, qname.name, qname.len, filp->f_pos, ino, type);
458 static int scan(struct ctl_table_header *head, ctl_table *table,
459 unsigned long *pos, struct file *file,
460 void *dirent, filldir_t filldir)
463 for (; table->procname; table++, (*pos)++) {
466 if (*pos < file->f_pos)
469 res = proc_sys_fill_cache(file, dirent, filldir, head, table);
473 file->f_pos = *pos + 1;
478 static int proc_sys_readdir(struct file *filp, void *dirent, filldir_t filldir)
480 struct dentry *dentry = filp->f_path.dentry;
481 struct inode *inode = dentry->d_inode;
482 struct ctl_table_header *head = grab_header(inode);
483 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
484 struct ctl_table_header *h = NULL;
489 return PTR_ERR(head);
491 if (table && !table->child) {
496 table = table ? table->child : head->ctl_table;
499 /* Avoid a switch here: arm builds fail with missing __cmpdi2 */
500 if (filp->f_pos == 0) {
501 if (filldir(dirent, ".", 1, filp->f_pos,
502 inode->i_ino, DT_DIR) < 0)
506 if (filp->f_pos == 1) {
507 if (filldir(dirent, "..", 2, filp->f_pos,
508 parent_ino(dentry), DT_DIR) < 0)
514 ret = scan(head, table, &pos, filp, dirent, filldir);
518 for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
519 if (h->attached_to != table)
521 ret = scan(h, h->attached_by, &pos, filp, dirent, filldir);
523 sysctl_head_finish(h);
529 sysctl_head_finish(head);
533 static int proc_sys_permission(struct inode *inode, int mask)
536 * sysctl entries that are not writeable,
537 * are _NOT_ writeable, capabilities or not.
539 struct ctl_table_header *head;
540 struct ctl_table *table;
543 /* Executable files are not allowed under /proc/sys/ */
544 if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))
547 head = grab_header(inode);
549 return PTR_ERR(head);
551 table = PROC_I(inode)->sysctl_entry;
552 if (!table) /* global root - r-xr-xr-x */
553 error = mask & MAY_WRITE ? -EACCES : 0;
554 else /* Use the permissions on the sysctl table entry */
555 error = sysctl_perm(head->root, table, mask & ~MAY_NOT_BLOCK);
557 sysctl_head_finish(head);
561 static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr)
563 struct inode *inode = dentry->d_inode;
566 if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))
569 error = inode_change_ok(inode, attr);
573 if ((attr->ia_valid & ATTR_SIZE) &&
574 attr->ia_size != i_size_read(inode)) {
575 error = vmtruncate(inode, attr->ia_size);
580 setattr_copy(inode, attr);
581 mark_inode_dirty(inode);
585 static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
587 struct inode *inode = dentry->d_inode;
588 struct ctl_table_header *head = grab_header(inode);
589 struct ctl_table *table = PROC_I(inode)->sysctl_entry;
592 return PTR_ERR(head);
594 generic_fillattr(inode, stat);
596 stat->mode = (stat->mode & S_IFMT) | table->mode;
598 sysctl_head_finish(head);
602 static const struct file_operations proc_sys_file_operations = {
603 .open = proc_sys_open,
604 .poll = proc_sys_poll,
605 .read = proc_sys_read,
606 .write = proc_sys_write,
607 .llseek = default_llseek,
610 static const struct file_operations proc_sys_dir_file_operations = {
611 .read = generic_read_dir,
612 .readdir = proc_sys_readdir,
613 .llseek = generic_file_llseek,
616 static const struct inode_operations proc_sys_inode_operations = {
617 .permission = proc_sys_permission,
618 .setattr = proc_sys_setattr,
619 .getattr = proc_sys_getattr,
622 static const struct inode_operations proc_sys_dir_operations = {
623 .lookup = proc_sys_lookup,
624 .permission = proc_sys_permission,
625 .setattr = proc_sys_setattr,
626 .getattr = proc_sys_getattr,
629 static int proc_sys_revalidate(struct dentry *dentry, struct nameidata *nd)
631 if (nd->flags & LOOKUP_RCU)
633 return !PROC_I(dentry->d_inode)->sysctl->unregistering;
636 static int proc_sys_delete(const struct dentry *dentry)
638 return !!PROC_I(dentry->d_inode)->sysctl->unregistering;
641 static int sysctl_is_seen(struct ctl_table_header *p)
643 struct ctl_table_set *set = p->set;
645 spin_lock(&sysctl_lock);
646 if (p->unregistering)
648 else if (!set->is_seen)
651 res = set->is_seen(set);
652 spin_unlock(&sysctl_lock);
656 static int proc_sys_compare(const struct dentry *parent,
657 const struct inode *pinode,
658 const struct dentry *dentry, const struct inode *inode,
659 unsigned int len, const char *str, const struct qstr *name)
661 struct ctl_table_header *head;
662 /* Although proc doesn't have negative dentries, rcu-walk means
663 * that inode here can be NULL */
664 /* AV: can it, indeed? */
667 if (name->len != len)
669 if (memcmp(name->name, str, len))
671 head = rcu_dereference(PROC_I(inode)->sysctl);
672 return !head || !sysctl_is_seen(head);
675 static const struct dentry_operations proc_sys_dentry_operations = {
676 .d_revalidate = proc_sys_revalidate,
677 .d_delete = proc_sys_delete,
678 .d_compare = proc_sys_compare,
681 static struct ctl_table *is_branch_in(struct ctl_table *branch,
682 struct ctl_table *table)
685 const char *s = branch->procname;
687 /* branch should have named subdirectory as its first element */
688 if (!s || !branch->child)
691 /* ... and nothing else */
692 if (branch[1].procname)
695 /* table should contain subdirectory with the same name */
696 for (p = table; p->procname; p++) {
699 if (p->procname && strcmp(p->procname, s) == 0)
705 /* see if attaching q to p would be an improvement */
706 static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q)
708 struct ctl_table *to = p->ctl_table, *by = q->ctl_table;
709 struct ctl_table *next;
711 int not_in_parent = !p->attached_by;
713 while ((next = is_branch_in(by, to)) != NULL) {
714 if (by == q->attached_by)
716 if (to == p->attached_by)
722 if (is_better && not_in_parent) {
729 #ifdef CONFIG_SYSCTL_SYSCALL_CHECK
730 static int sysctl_depth(struct ctl_table *table)
732 struct ctl_table *tmp;
736 for (tmp = table; tmp->parent; tmp = tmp->parent)
742 static struct ctl_table *sysctl_parent(struct ctl_table *table, int n)
746 for (i = 0; table && i < n; i++)
747 table = table->parent;
753 static void sysctl_print_path(struct ctl_table *table)
755 struct ctl_table *tmp;
757 depth = sysctl_depth(table);
758 if (table->procname) {
759 for (i = depth; i >= 0; i--) {
760 tmp = sysctl_parent(table, i);
761 printk("/%s", tmp->procname?tmp->procname:"");
767 static struct ctl_table *sysctl_check_lookup(struct nsproxy *namespaces,
768 struct ctl_table *table)
770 struct ctl_table_header *head;
771 struct ctl_table *ref, *test;
772 int depth, cur_depth;
774 depth = sysctl_depth(table);
776 for (head = __sysctl_head_next(namespaces, NULL); head;
777 head = __sysctl_head_next(namespaces, head)) {
779 ref = head->ctl_table;
781 test = sysctl_parent(table, cur_depth);
782 for (; ref->procname; ref++) {
784 if (cur_depth && !ref->child)
787 if (test->procname && ref->procname &&
788 (strcmp(test->procname, ref->procname) == 0))
792 if (cur_depth != 0) {
803 sysctl_head_finish(head);
807 static void set_fail(const char **fail, struct ctl_table *table, const char *str)
810 printk(KERN_ERR "sysctl table check failed: ");
811 sysctl_print_path(table);
812 printk(" %s\n", *fail);
818 static void sysctl_check_leaf(struct nsproxy *namespaces,
819 struct ctl_table *table, const char **fail)
821 struct ctl_table *ref;
823 ref = sysctl_check_lookup(namespaces, table);
824 if (ref && (ref != table))
825 set_fail(fail, table, "Sysctl already exists");
828 static int sysctl_check_table(struct nsproxy *namespaces, struct ctl_table *table)
831 for (; table->procname; table++) {
832 const char *fail = NULL;
835 if (!table->parent->procname)
836 set_fail(&fail, table, "Parent without procname");
840 set_fail(&fail, table, "Directory with data?");
842 set_fail(&fail, table, "Directory with maxlen?");
843 if ((table->mode & (S_IRUGO|S_IXUGO)) != table->mode)
844 set_fail(&fail, table, "Writable sysctl directory");
845 if (table->proc_handler)
846 set_fail(&fail, table, "Directory with proc_handler");
848 set_fail(&fail, table, "Directory with extra1");
850 set_fail(&fail, table, "Directory with extra2");
852 if ((table->proc_handler == proc_dostring) ||
853 (table->proc_handler == proc_dointvec) ||
854 (table->proc_handler == proc_dointvec_minmax) ||
855 (table->proc_handler == proc_dointvec_jiffies) ||
856 (table->proc_handler == proc_dointvec_userhz_jiffies) ||
857 (table->proc_handler == proc_dointvec_ms_jiffies) ||
858 (table->proc_handler == proc_doulongvec_minmax) ||
859 (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) {
861 set_fail(&fail, table, "No data");
863 set_fail(&fail, table, "No maxlen");
865 #ifdef CONFIG_PROC_SYSCTL
866 if (!table->proc_handler)
867 set_fail(&fail, table, "No proc_handler");
869 sysctl_check_leaf(namespaces, table, &fail);
871 if (table->mode > 0777)
872 set_fail(&fail, table, "bogus .mode");
874 set_fail(&fail, table, NULL);
878 error |= sysctl_check_table(namespaces, table->child);
882 #endif /* CONFIG_SYSCTL_SYSCALL_CHECK */
885 * __register_sysctl_table - register a sysctl table
886 * @root: List of sysctl headers to register on
887 * @namespaces: Data to compute which lists of sysctl entries are visible
888 * @path: The path to the directory the sysctl table is in.
889 * @table: the top-level table structure
891 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
892 * array. A completely 0 filled entry terminates the table.
894 * The members of the &struct ctl_table structure are used as follows:
896 * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
897 * enter a sysctl file
899 * data - a pointer to data for use by proc_handler
901 * maxlen - the maximum size in bytes of the data
903 * mode - the file permissions for the /proc/sys file, and for sysctl(2)
905 * child - a pointer to the child sysctl table if this entry is a directory, or
908 * proc_handler - the text handler routine (described below)
910 * de - for internal use by the sysctl routines
912 * extra1, extra2 - extra pointers usable by the proc handler routines
914 * Leaf nodes in the sysctl tree will be represented by a single file
915 * under /proc; non-leaf nodes will be represented by directories.
917 * sysctl(2) can automatically manage read and write requests through
918 * the sysctl table. The data and maxlen fields of the ctl_table
919 * struct enable minimal validation of the values being written to be
920 * performed, and the mode field allows minimal authentication.
922 * There must be a proc_handler routine for any terminal nodes
923 * mirrored under /proc/sys (non-terminals are handled by a built-in
924 * directory handler). Several default handlers are available to
925 * cover common cases -
927 * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
928 * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
929 * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
931 * It is the handler's job to read the input buffer from user memory
932 * and process it. The handler should return 0 on success.
934 * This routine returns %NULL on a failure to register, and a pointer
935 * to the table header on success.
937 struct ctl_table_header *__register_sysctl_table(
938 struct ctl_table_root *root,
939 struct nsproxy *namespaces,
940 const char *path, struct ctl_table *table)
942 struct ctl_table_header *header;
943 struct ctl_table *new, **prevp;
944 const char *name, *nextname;
945 unsigned int npath = 0;
946 struct ctl_table_set *set;
947 size_t path_bytes = 0;
950 /* Count the path components */
951 for (name = path; name; name = nextname) {
953 nextname = strchr(name, '/');
955 namelen = nextname - name;
958 namelen = strlen(name);
962 path_bytes += namelen + 1;
967 * For each path component, allocate a 2-element ctl_table array.
968 * The first array element will be filled with the sysctl entry
969 * for this, the second will be the sentinel (procname == 0).
971 * We allocate everything in one go so that we don't have to
972 * worry about freeing additional memory in unregister_sysctl_table.
974 header = kzalloc(sizeof(struct ctl_table_header) + path_bytes +
975 (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL);
979 new = (struct ctl_table *) (header + 1);
980 new_name = (char *)(new + (2 * npath));
982 /* Now connect the dots */
983 prevp = &header->ctl_table;
984 for (name = path; name; name = nextname) {
986 nextname = strchr(name, '/');
988 namelen = nextname - name;
991 namelen = strlen(name);
995 memcpy(new_name, name, namelen);
996 new_name[namelen] = '\0';
998 new->procname = new_name;
1002 prevp = &new->child;
1005 new_name += namelen + 1;
1008 header->ctl_table_arg = table;
1010 INIT_LIST_HEAD(&header->ctl_entry);
1012 header->unregistering = NULL;
1013 header->root = root;
1014 sysctl_set_parent(NULL, header->ctl_table);
1016 #ifdef CONFIG_SYSCTL_SYSCALL_CHECK
1017 if (sysctl_check_table(namespaces, header->ctl_table)) {
1022 spin_lock(&sysctl_lock);
1023 header->set = lookup_header_set(root, namespaces);
1024 header->attached_by = header->ctl_table;
1025 header->attached_to = root_table;
1026 header->parent = &root_table_header;
1028 root = header->root;
1030 struct ctl_table_header *p;
1031 list_for_each_entry(p, &set->list, ctl_entry) {
1032 if (p->unregistering)
1034 try_attach(p, header);
1036 if (root == &sysctl_table_root)
1038 root = list_entry(root->root_list.prev,
1039 struct ctl_table_root, root_list);
1040 set = lookup_header_set(root, namespaces);
1042 header->parent->count++;
1043 list_add_tail(&header->ctl_entry, &header->set->list);
1044 spin_unlock(&sysctl_lock);
1049 static char *append_path(const char *path, char *pos, const char *name)
1052 namelen = strlen(name);
1053 if (((pos - path) + namelen + 2) >= PATH_MAX)
1055 memcpy(pos, name, namelen);
1057 pos[namelen + 1] = '\0';
1063 * __register_sysctl_paths - register a sysctl table hierarchy
1064 * @root: List of sysctl headers to register on
1065 * @namespaces: Data to compute which lists of sysctl entries are visible
1066 * @path: The path to the directory the sysctl table is in.
1067 * @table: the top-level table structure
1069 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1070 * array. A completely 0 filled entry terminates the table.
1072 * See __register_sysctl_table for more details.
1074 struct ctl_table_header *__register_sysctl_paths(
1075 struct ctl_table_root *root,
1076 struct nsproxy *namespaces,
1077 const struct ctl_path *path, struct ctl_table *table)
1079 struct ctl_table *ctl_table_arg = table;
1080 struct ctl_table_header *header = NULL;
1081 const struct ctl_path *component;
1082 char *new_path, *pos;
1084 pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL);
1089 for (component = path; component->procname; component++) {
1090 pos = append_path(new_path, pos, component->procname);
1094 while (table->procname && table->child && !table[1].procname) {
1095 pos = append_path(new_path, pos, table->procname);
1098 table = table->child;
1100 header = __register_sysctl_table(root, namespaces, new_path, table);
1102 header->ctl_table_arg = ctl_table_arg;
1109 * register_sysctl_table_path - register a sysctl table hierarchy
1110 * @path: The path to the directory the sysctl table is in.
1111 * @table: the top-level table structure
1113 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1114 * array. A completely 0 filled entry terminates the table.
1116 * See __register_sysctl_paths for more details.
1118 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
1119 struct ctl_table *table)
1121 return __register_sysctl_paths(&sysctl_table_root, current->nsproxy,
1124 EXPORT_SYMBOL(register_sysctl_paths);
1127 * register_sysctl_table - register a sysctl table hierarchy
1128 * @table: the top-level table structure
1130 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1131 * array. A completely 0 filled entry terminates the table.
1133 * See register_sysctl_paths for more details.
1135 struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
1137 static const struct ctl_path null_path[] = { {} };
1139 return register_sysctl_paths(null_path, table);
1141 EXPORT_SYMBOL(register_sysctl_table);
1144 * unregister_sysctl_table - unregister a sysctl table hierarchy
1145 * @header: the header returned from register_sysctl_table
1147 * Unregisters the sysctl table and all children. proc entries may not
1148 * actually be removed until they are no longer used by anyone.
1150 void unregister_sysctl_table(struct ctl_table_header * header)
1157 spin_lock(&sysctl_lock);
1158 start_unregistering(header);
1159 if (!--header->parent->count) {
1161 kfree_rcu(header->parent, rcu);
1163 if (!--header->count)
1164 kfree_rcu(header, rcu);
1165 spin_unlock(&sysctl_lock);
1167 EXPORT_SYMBOL(unregister_sysctl_table);
1169 void setup_sysctl_set(struct ctl_table_set *p,
1170 int (*is_seen)(struct ctl_table_set *))
1172 INIT_LIST_HEAD(&p->list);
1173 p->is_seen = is_seen;
1176 void retire_sysctl_set(struct ctl_table_set *set)
1178 WARN_ON(!list_empty(&set->list));
1181 int __init proc_sys_init(void)
1183 struct proc_dir_entry *proc_sys_root;
1185 proc_sys_root = proc_mkdir("sys", NULL);
1186 proc_sys_root->proc_iops = &proc_sys_dir_operations;
1187 proc_sys_root->proc_fops = &proc_sys_dir_file_operations;
1188 proc_sys_root->nlink = 0;
1190 return sysctl_init();