mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-30 12:49:36 +00:00
![Linus Torvalds](/assets/img/avatar_default.png)
Pull more vfs updates from Al Viro: ">rename2() work from Miklos + current_time() from Deepa" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs: Replace current_fs_time() with current_time() fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps fs: Replace CURRENT_TIME with current_time() for inode timestamps fs: proc: Delete inode time initializations in proc_alloc_inode() vfs: Add current_time() api vfs: add note about i_op->rename changes to porting fs: rename "rename2" i_op to "rename" vfs: remove unused i_op->rename fs: make remaining filesystems use .rename2 libfs: support RENAME_NOREPLACE in simple_rename() fs: support RENAME_NOREPLACE for local filesystems ncpfs: fix unused variable warning
1625 lines
39 KiB
C
1625 lines
39 KiB
C
/*
|
|
* /proc/sys support
|
|
*/
|
|
#include <linux/init.h>
|
|
#include <linux/sysctl.h>
|
|
#include <linux/poll.h>
|
|
#include <linux/proc_fs.h>
|
|
#include <linux/printk.h>
|
|
#include <linux/security.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/namei.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/module.h>
|
|
#include "internal.h"
|
|
|
|
static const struct dentry_operations proc_sys_dentry_operations;
|
|
static const struct file_operations proc_sys_file_operations;
|
|
static const struct inode_operations proc_sys_inode_operations;
|
|
static const struct file_operations proc_sys_dir_file_operations;
|
|
static const struct inode_operations proc_sys_dir_operations;
|
|
|
|
/* Support for permanently empty directories */
|
|
|
|
struct ctl_table sysctl_mount_point[] = {
|
|
{ }
|
|
};
|
|
|
|
static bool is_empty_dir(struct ctl_table_header *head)
|
|
{
|
|
return head->ctl_table[0].child == sysctl_mount_point;
|
|
}
|
|
|
|
static void set_empty_dir(struct ctl_dir *dir)
|
|
{
|
|
dir->header.ctl_table[0].child = sysctl_mount_point;
|
|
}
|
|
|
|
static void clear_empty_dir(struct ctl_dir *dir)
|
|
|
|
{
|
|
dir->header.ctl_table[0].child = NULL;
|
|
}
|
|
|
|
void proc_sys_poll_notify(struct ctl_table_poll *poll)
|
|
{
|
|
if (!poll)
|
|
return;
|
|
|
|
atomic_inc(&poll->event);
|
|
wake_up_interruptible(&poll->wait);
|
|
}
|
|
|
|
static struct ctl_table root_table[] = {
|
|
{
|
|
.procname = "",
|
|
.mode = S_IFDIR|S_IRUGO|S_IXUGO,
|
|
},
|
|
{ }
|
|
};
|
|
static struct ctl_table_root sysctl_table_root = {
|
|
.default_set.dir.header = {
|
|
{{.count = 1,
|
|
.nreg = 1,
|
|
.ctl_table = root_table }},
|
|
.ctl_table_arg = root_table,
|
|
.root = &sysctl_table_root,
|
|
.set = &sysctl_table_root.default_set,
|
|
},
|
|
};
|
|
|
|
static DEFINE_SPINLOCK(sysctl_lock);
|
|
|
|
static void drop_sysctl_table(struct ctl_table_header *header);
|
|
static int sysctl_follow_link(struct ctl_table_header **phead,
|
|
struct ctl_table **pentry);
|
|
static int insert_links(struct ctl_table_header *head);
|
|
static void put_links(struct ctl_table_header *header);
|
|
|
|
static void sysctl_print_dir(struct ctl_dir *dir)
|
|
{
|
|
if (dir->header.parent)
|
|
sysctl_print_dir(dir->header.parent);
|
|
pr_cont("%s/", dir->header.ctl_table[0].procname);
|
|
}
|
|
|
|
static int namecmp(const char *name1, int len1, const char *name2, int len2)
|
|
{
|
|
int minlen;
|
|
int cmp;
|
|
|
|
minlen = len1;
|
|
if (minlen > len2)
|
|
minlen = len2;
|
|
|
|
cmp = memcmp(name1, name2, minlen);
|
|
if (cmp == 0)
|
|
cmp = len1 - len2;
|
|
return cmp;
|
|
}
|
|
|
|
/* Called under sysctl_lock */
|
|
static struct ctl_table *find_entry(struct ctl_table_header **phead,
|
|
struct ctl_dir *dir, const char *name, int namelen)
|
|
{
|
|
struct ctl_table_header *head;
|
|
struct ctl_table *entry;
|
|
struct rb_node *node = dir->root.rb_node;
|
|
|
|
while (node)
|
|
{
|
|
struct ctl_node *ctl_node;
|
|
const char *procname;
|
|
int cmp;
|
|
|
|
ctl_node = rb_entry(node, struct ctl_node, node);
|
|
head = ctl_node->header;
|
|
entry = &head->ctl_table[ctl_node - head->node];
|
|
procname = entry->procname;
|
|
|
|
cmp = namecmp(name, namelen, procname, strlen(procname));
|
|
if (cmp < 0)
|
|
node = node->rb_left;
|
|
else if (cmp > 0)
|
|
node = node->rb_right;
|
|
else {
|
|
*phead = head;
|
|
return entry;
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry)
|
|
{
|
|
struct rb_node *node = &head->node[entry - head->ctl_table].node;
|
|
struct rb_node **p = &head->parent->root.rb_node;
|
|
struct rb_node *parent = NULL;
|
|
const char *name = entry->procname;
|
|
int namelen = strlen(name);
|
|
|
|
while (*p) {
|
|
struct ctl_table_header *parent_head;
|
|
struct ctl_table *parent_entry;
|
|
struct ctl_node *parent_node;
|
|
const char *parent_name;
|
|
int cmp;
|
|
|
|
parent = *p;
|
|
parent_node = rb_entry(parent, struct ctl_node, node);
|
|
parent_head = parent_node->header;
|
|
parent_entry = &parent_head->ctl_table[parent_node - parent_head->node];
|
|
parent_name = parent_entry->procname;
|
|
|
|
cmp = namecmp(name, namelen, parent_name, strlen(parent_name));
|
|
if (cmp < 0)
|
|
p = &(*p)->rb_left;
|
|
else if (cmp > 0)
|
|
p = &(*p)->rb_right;
|
|
else {
|
|
pr_err("sysctl duplicate entry: ");
|
|
sysctl_print_dir(head->parent);
|
|
pr_cont("/%s\n", entry->procname);
|
|
return -EEXIST;
|
|
}
|
|
}
|
|
|
|
rb_link_node(node, parent, p);
|
|
rb_insert_color(node, &head->parent->root);
|
|
return 0;
|
|
}
|
|
|
|
static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry)
|
|
{
|
|
struct rb_node *node = &head->node[entry - head->ctl_table].node;
|
|
|
|
rb_erase(node, &head->parent->root);
|
|
}
|
|
|
|
static void init_header(struct ctl_table_header *head,
|
|
struct ctl_table_root *root, struct ctl_table_set *set,
|
|
struct ctl_node *node, struct ctl_table *table)
|
|
{
|
|
head->ctl_table = table;
|
|
head->ctl_table_arg = table;
|
|
head->used = 0;
|
|
head->count = 1;
|
|
head->nreg = 1;
|
|
head->unregistering = NULL;
|
|
head->root = root;
|
|
head->set = set;
|
|
head->parent = NULL;
|
|
head->node = node;
|
|
if (node) {
|
|
struct ctl_table *entry;
|
|
for (entry = table; entry->procname; entry++, node++)
|
|
node->header = head;
|
|
}
|
|
}
|
|
|
|
static void erase_header(struct ctl_table_header *head)
|
|
{
|
|
struct ctl_table *entry;
|
|
for (entry = head->ctl_table; entry->procname; entry++)
|
|
erase_entry(head, entry);
|
|
}
|
|
|
|
static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header)
|
|
{
|
|
struct ctl_table *entry;
|
|
int err;
|
|
|
|
/* Is this a permanently empty directory? */
|
|
if (is_empty_dir(&dir->header))
|
|
return -EROFS;
|
|
|
|
/* Am I creating a permanently empty directory? */
|
|
if (header->ctl_table == sysctl_mount_point) {
|
|
if (!RB_EMPTY_ROOT(&dir->root))
|
|
return -EINVAL;
|
|
set_empty_dir(dir);
|
|
}
|
|
|
|
dir->header.nreg++;
|
|
header->parent = dir;
|
|
err = insert_links(header);
|
|
if (err)
|
|
goto fail_links;
|
|
for (entry = header->ctl_table; entry->procname; entry++) {
|
|
err = insert_entry(header, entry);
|
|
if (err)
|
|
goto fail;
|
|
}
|
|
return 0;
|
|
fail:
|
|
erase_header(header);
|
|
put_links(header);
|
|
fail_links:
|
|
if (header->ctl_table == sysctl_mount_point)
|
|
clear_empty_dir(dir);
|
|
header->parent = NULL;
|
|
drop_sysctl_table(&dir->header);
|
|
return err;
|
|
}
|
|
|
|
/* called under sysctl_lock */
|
|
static int use_table(struct ctl_table_header *p)
|
|
{
|
|
if (unlikely(p->unregistering))
|
|
return 0;
|
|
p->used++;
|
|
return 1;
|
|
}
|
|
|
|
/* called under sysctl_lock */
|
|
static void unuse_table(struct ctl_table_header *p)
|
|
{
|
|
if (!--p->used)
|
|
if (unlikely(p->unregistering))
|
|
complete(p->unregistering);
|
|
}
|
|
|
|
/* called under sysctl_lock, will reacquire if has to wait */
|
|
static void start_unregistering(struct ctl_table_header *p)
|
|
{
|
|
/*
|
|
* if p->used is 0, nobody will ever touch that entry again;
|
|
* we'll eliminate all paths to it before dropping sysctl_lock
|
|
*/
|
|
if (unlikely(p->used)) {
|
|
struct completion wait;
|
|
init_completion(&wait);
|
|
p->unregistering = &wait;
|
|
spin_unlock(&sysctl_lock);
|
|
wait_for_completion(&wait);
|
|
spin_lock(&sysctl_lock);
|
|
} else {
|
|
/* anything non-NULL; we'll never dereference it */
|
|
p->unregistering = ERR_PTR(-EINVAL);
|
|
}
|
|
/*
|
|
* do not remove from the list until nobody holds it; walking the
|
|
* list in do_sysctl() relies on that.
|
|
*/
|
|
erase_header(p);
|
|
}
|
|
|
|
static void sysctl_head_get(struct ctl_table_header *head)
|
|
{
|
|
spin_lock(&sysctl_lock);
|
|
head->count++;
|
|
spin_unlock(&sysctl_lock);
|
|
}
|
|
|
|
void sysctl_head_put(struct ctl_table_header *head)
|
|
{
|
|
spin_lock(&sysctl_lock);
|
|
if (!--head->count)
|
|
kfree_rcu(head, rcu);
|
|
spin_unlock(&sysctl_lock);
|
|
}
|
|
|
|
static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
|
|
{
|
|
BUG_ON(!head);
|
|
spin_lock(&sysctl_lock);
|
|
if (!use_table(head))
|
|
head = ERR_PTR(-ENOENT);
|
|
spin_unlock(&sysctl_lock);
|
|
return head;
|
|
}
|
|
|
|
static void sysctl_head_finish(struct ctl_table_header *head)
|
|
{
|
|
if (!head)
|
|
return;
|
|
spin_lock(&sysctl_lock);
|
|
unuse_table(head);
|
|
spin_unlock(&sysctl_lock);
|
|
}
|
|
|
|
static struct ctl_table_set *
|
|
lookup_header_set(struct ctl_table_root *root)
|
|
{
|
|
struct ctl_table_set *set = &root->default_set;
|
|
if (root->lookup)
|
|
set = root->lookup(root);
|
|
return set;
|
|
}
|
|
|
|
static struct ctl_table *lookup_entry(struct ctl_table_header **phead,
|
|
struct ctl_dir *dir,
|
|
const char *name, int namelen)
|
|
{
|
|
struct ctl_table_header *head;
|
|
struct ctl_table *entry;
|
|
|
|
spin_lock(&sysctl_lock);
|
|
entry = find_entry(&head, dir, name, namelen);
|
|
if (entry && use_table(head))
|
|
*phead = head;
|
|
else
|
|
entry = NULL;
|
|
spin_unlock(&sysctl_lock);
|
|
return entry;
|
|
}
|
|
|
|
static struct ctl_node *first_usable_entry(struct rb_node *node)
|
|
{
|
|
struct ctl_node *ctl_node;
|
|
|
|
for (;node; node = rb_next(node)) {
|
|
ctl_node = rb_entry(node, struct ctl_node, node);
|
|
if (use_table(ctl_node->header))
|
|
return ctl_node;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static void first_entry(struct ctl_dir *dir,
|
|
struct ctl_table_header **phead, struct ctl_table **pentry)
|
|
{
|
|
struct ctl_table_header *head = NULL;
|
|
struct ctl_table *entry = NULL;
|
|
struct ctl_node *ctl_node;
|
|
|
|
spin_lock(&sysctl_lock);
|
|
ctl_node = first_usable_entry(rb_first(&dir->root));
|
|
spin_unlock(&sysctl_lock);
|
|
if (ctl_node) {
|
|
head = ctl_node->header;
|
|
entry = &head->ctl_table[ctl_node - head->node];
|
|
}
|
|
*phead = head;
|
|
*pentry = entry;
|
|
}
|
|
|
|
static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry)
|
|
{
|
|
struct ctl_table_header *head = *phead;
|
|
struct ctl_table *entry = *pentry;
|
|
struct ctl_node *ctl_node = &head->node[entry - head->ctl_table];
|
|
|
|
spin_lock(&sysctl_lock);
|
|
unuse_table(head);
|
|
|
|
ctl_node = first_usable_entry(rb_next(&ctl_node->node));
|
|
spin_unlock(&sysctl_lock);
|
|
head = NULL;
|
|
if (ctl_node) {
|
|
head = ctl_node->header;
|
|
entry = &head->ctl_table[ctl_node - head->node];
|
|
}
|
|
*phead = head;
|
|
*pentry = entry;
|
|
}
|
|
|
|
void register_sysctl_root(struct ctl_table_root *root)
|
|
{
|
|
}
|
|
|
|
/*
|
|
* sysctl_perm does NOT grant the superuser all rights automatically, because
|
|
* some sysctl variables are readonly even to root.
|
|
*/
|
|
|
|
static int test_perm(int mode, int op)
|
|
{
|
|
if (uid_eq(current_euid(), GLOBAL_ROOT_UID))
|
|
mode >>= 6;
|
|
else if (in_egroup_p(GLOBAL_ROOT_GID))
|
|
mode >>= 3;
|
|
if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
|
|
return 0;
|
|
return -EACCES;
|
|
}
|
|
|
|
static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op)
|
|
{
|
|
struct ctl_table_root *root = head->root;
|
|
int mode;
|
|
|
|
if (root->permissions)
|
|
mode = root->permissions(head, table);
|
|
else
|
|
mode = table->mode;
|
|
|
|
return test_perm(mode, op);
|
|
}
|
|
|
|
static struct inode *proc_sys_make_inode(struct super_block *sb,
|
|
struct ctl_table_header *head, struct ctl_table *table)
|
|
{
|
|
struct ctl_table_root *root = head->root;
|
|
struct inode *inode;
|
|
struct proc_inode *ei;
|
|
|
|
inode = new_inode(sb);
|
|
if (!inode)
|
|
goto out;
|
|
|
|
inode->i_ino = get_next_ino();
|
|
|
|
sysctl_head_get(head);
|
|
ei = PROC_I(inode);
|
|
ei->sysctl = head;
|
|
ei->sysctl_entry = table;
|
|
|
|
inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
|
|
inode->i_mode = table->mode;
|
|
if (!S_ISDIR(table->mode)) {
|
|
inode->i_mode |= S_IFREG;
|
|
inode->i_op = &proc_sys_inode_operations;
|
|
inode->i_fop = &proc_sys_file_operations;
|
|
} else {
|
|
inode->i_mode |= S_IFDIR;
|
|
inode->i_op = &proc_sys_dir_operations;
|
|
inode->i_fop = &proc_sys_dir_file_operations;
|
|
if (is_empty_dir(head))
|
|
make_empty_dir_inode(inode);
|
|
}
|
|
|
|
if (root->set_ownership)
|
|
root->set_ownership(head, table, &inode->i_uid, &inode->i_gid);
|
|
|
|
out:
|
|
return inode;
|
|
}
|
|
|
|
static struct ctl_table_header *grab_header(struct inode *inode)
|
|
{
|
|
struct ctl_table_header *head = PROC_I(inode)->sysctl;
|
|
if (!head)
|
|
head = &sysctl_table_root.default_set.dir.header;
|
|
return sysctl_head_grab(head);
|
|
}
|
|
|
|
static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
|
|
unsigned int flags)
|
|
{
|
|
struct ctl_table_header *head = grab_header(dir);
|
|
struct ctl_table_header *h = NULL;
|
|
const struct qstr *name = &dentry->d_name;
|
|
struct ctl_table *p;
|
|
struct inode *inode;
|
|
struct dentry *err = ERR_PTR(-ENOENT);
|
|
struct ctl_dir *ctl_dir;
|
|
int ret;
|
|
|
|
if (IS_ERR(head))
|
|
return ERR_CAST(head);
|
|
|
|
ctl_dir = container_of(head, struct ctl_dir, header);
|
|
|
|
p = lookup_entry(&h, ctl_dir, name->name, name->len);
|
|
if (!p)
|
|
goto out;
|
|
|
|
if (S_ISLNK(p->mode)) {
|
|
ret = sysctl_follow_link(&h, &p);
|
|
err = ERR_PTR(ret);
|
|
if (ret)
|
|
goto out;
|
|
}
|
|
|
|
err = ERR_PTR(-ENOMEM);
|
|
inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
|
|
if (!inode)
|
|
goto out;
|
|
|
|
err = NULL;
|
|
d_set_d_op(dentry, &proc_sys_dentry_operations);
|
|
d_add(dentry, inode);
|
|
|
|
out:
|
|
if (h)
|
|
sysctl_head_finish(h);
|
|
sysctl_head_finish(head);
|
|
return err;
|
|
}
|
|
|
|
static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,
|
|
size_t count, loff_t *ppos, int write)
|
|
{
|
|
struct inode *inode = file_inode(filp);
|
|
struct ctl_table_header *head = grab_header(inode);
|
|
struct ctl_table *table = PROC_I(inode)->sysctl_entry;
|
|
ssize_t error;
|
|
size_t res;
|
|
|
|
if (IS_ERR(head))
|
|
return PTR_ERR(head);
|
|
|
|
/*
|
|
* At this point we know that the sysctl was not unregistered
|
|
* and won't be until we finish.
|
|
*/
|
|
error = -EPERM;
|
|
if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ))
|
|
goto out;
|
|
|
|
/* if that can happen at all, it should be -EINVAL, not -EISDIR */
|
|
error = -EINVAL;
|
|
if (!table->proc_handler)
|
|
goto out;
|
|
|
|
/* careful: calling conventions are nasty here */
|
|
res = count;
|
|
error = table->proc_handler(table, write, buf, &res, ppos);
|
|
if (!error)
|
|
error = res;
|
|
out:
|
|
sysctl_head_finish(head);
|
|
|
|
return error;
|
|
}
|
|
|
|
static ssize_t proc_sys_read(struct file *filp, char __user *buf,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0);
|
|
}
|
|
|
|
static ssize_t proc_sys_write(struct file *filp, const char __user *buf,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1);
|
|
}
|
|
|
|
static int proc_sys_open(struct inode *inode, struct file *filp)
|
|
{
|
|
struct ctl_table_header *head = grab_header(inode);
|
|
struct ctl_table *table = PROC_I(inode)->sysctl_entry;
|
|
|
|
/* sysctl was unregistered */
|
|
if (IS_ERR(head))
|
|
return PTR_ERR(head);
|
|
|
|
if (table->poll)
|
|
filp->private_data = proc_sys_poll_event(table->poll);
|
|
|
|
sysctl_head_finish(head);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static unsigned int proc_sys_poll(struct file *filp, poll_table *wait)
|
|
{
|
|
struct inode *inode = file_inode(filp);
|
|
struct ctl_table_header *head = grab_header(inode);
|
|
struct ctl_table *table = PROC_I(inode)->sysctl_entry;
|
|
unsigned int ret = DEFAULT_POLLMASK;
|
|
unsigned long event;
|
|
|
|
/* sysctl was unregistered */
|
|
if (IS_ERR(head))
|
|
return POLLERR | POLLHUP;
|
|
|
|
if (!table->proc_handler)
|
|
goto out;
|
|
|
|
if (!table->poll)
|
|
goto out;
|
|
|
|
event = (unsigned long)filp->private_data;
|
|
poll_wait(filp, &table->poll->wait, wait);
|
|
|
|
if (event != atomic_read(&table->poll->event)) {
|
|
filp->private_data = proc_sys_poll_event(table->poll);
|
|
ret = POLLIN | POLLRDNORM | POLLERR | POLLPRI;
|
|
}
|
|
|
|
out:
|
|
sysctl_head_finish(head);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static bool proc_sys_fill_cache(struct file *file,
|
|
struct dir_context *ctx,
|
|
struct ctl_table_header *head,
|
|
struct ctl_table *table)
|
|
{
|
|
struct dentry *child, *dir = file->f_path.dentry;
|
|
struct inode *inode;
|
|
struct qstr qname;
|
|
ino_t ino = 0;
|
|
unsigned type = DT_UNKNOWN;
|
|
|
|
qname.name = table->procname;
|
|
qname.len = strlen(table->procname);
|
|
qname.hash = full_name_hash(dir, qname.name, qname.len);
|
|
|
|
child = d_lookup(dir, &qname);
|
|
if (!child) {
|
|
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
|
|
child = d_alloc_parallel(dir, &qname, &wq);
|
|
if (IS_ERR(child))
|
|
return false;
|
|
if (d_in_lookup(child)) {
|
|
inode = proc_sys_make_inode(dir->d_sb, head, table);
|
|
if (!inode) {
|
|
d_lookup_done(child);
|
|
dput(child);
|
|
return false;
|
|
}
|
|
d_set_d_op(child, &proc_sys_dentry_operations);
|
|
d_add(child, inode);
|
|
}
|
|
}
|
|
inode = d_inode(child);
|
|
ino = inode->i_ino;
|
|
type = inode->i_mode >> 12;
|
|
dput(child);
|
|
return dir_emit(ctx, qname.name, qname.len, ino, type);
|
|
}
|
|
|
|
static bool proc_sys_link_fill_cache(struct file *file,
|
|
struct dir_context *ctx,
|
|
struct ctl_table_header *head,
|
|
struct ctl_table *table)
|
|
{
|
|
bool ret = true;
|
|
head = sysctl_head_grab(head);
|
|
|
|
if (S_ISLNK(table->mode)) {
|
|
/* It is not an error if we can not follow the link ignore it */
|
|
int err = sysctl_follow_link(&head, &table);
|
|
if (err)
|
|
goto out;
|
|
}
|
|
|
|
ret = proc_sys_fill_cache(file, ctx, head, table);
|
|
out:
|
|
sysctl_head_finish(head);
|
|
return ret;
|
|
}
|
|
|
|
static int scan(struct ctl_table_header *head, struct ctl_table *table,
|
|
unsigned long *pos, struct file *file,
|
|
struct dir_context *ctx)
|
|
{
|
|
bool res;
|
|
|
|
if ((*pos)++ < ctx->pos)
|
|
return true;
|
|
|
|
if (unlikely(S_ISLNK(table->mode)))
|
|
res = proc_sys_link_fill_cache(file, ctx, head, table);
|
|
else
|
|
res = proc_sys_fill_cache(file, ctx, head, table);
|
|
|
|
if (res)
|
|
ctx->pos = *pos;
|
|
|
|
return res;
|
|
}
|
|
|
|
static int proc_sys_readdir(struct file *file, struct dir_context *ctx)
|
|
{
|
|
struct ctl_table_header *head = grab_header(file_inode(file));
|
|
struct ctl_table_header *h = NULL;
|
|
struct ctl_table *entry;
|
|
struct ctl_dir *ctl_dir;
|
|
unsigned long pos;
|
|
|
|
if (IS_ERR(head))
|
|
return PTR_ERR(head);
|
|
|
|
ctl_dir = container_of(head, struct ctl_dir, header);
|
|
|
|
if (!dir_emit_dots(file, ctx))
|
|
return 0;
|
|
|
|
pos = 2;
|
|
|
|
for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) {
|
|
if (!scan(h, entry, &pos, file, ctx)) {
|
|
sysctl_head_finish(h);
|
|
break;
|
|
}
|
|
}
|
|
sysctl_head_finish(head);
|
|
return 0;
|
|
}
|
|
|
|
static int proc_sys_permission(struct inode *inode, int mask)
|
|
{
|
|
/*
|
|
* sysctl entries that are not writeable,
|
|
* are _NOT_ writeable, capabilities or not.
|
|
*/
|
|
struct ctl_table_header *head;
|
|
struct ctl_table *table;
|
|
int error;
|
|
|
|
/* Executable files are not allowed under /proc/sys/ */
|
|
if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode))
|
|
return -EACCES;
|
|
|
|
head = grab_header(inode);
|
|
if (IS_ERR(head))
|
|
return PTR_ERR(head);
|
|
|
|
table = PROC_I(inode)->sysctl_entry;
|
|
if (!table) /* global root - r-xr-xr-x */
|
|
error = mask & MAY_WRITE ? -EACCES : 0;
|
|
else /* Use the permissions on the sysctl table entry */
|
|
error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK);
|
|
|
|
sysctl_head_finish(head);
|
|
return error;
|
|
}
|
|
|
|
static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr)
|
|
{
|
|
struct inode *inode = d_inode(dentry);
|
|
int error;
|
|
|
|
if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))
|
|
return -EPERM;
|
|
|
|
error = setattr_prepare(dentry, attr);
|
|
if (error)
|
|
return error;
|
|
|
|
setattr_copy(inode, attr);
|
|
mark_inode_dirty(inode);
|
|
return 0;
|
|
}
|
|
|
|
static int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
|
|
{
|
|
struct inode *inode = d_inode(dentry);
|
|
struct ctl_table_header *head = grab_header(inode);
|
|
struct ctl_table *table = PROC_I(inode)->sysctl_entry;
|
|
|
|
if (IS_ERR(head))
|
|
return PTR_ERR(head);
|
|
|
|
generic_fillattr(inode, stat);
|
|
if (table)
|
|
stat->mode = (stat->mode & S_IFMT) | table->mode;
|
|
|
|
sysctl_head_finish(head);
|
|
return 0;
|
|
}
|
|
|
|
static const struct file_operations proc_sys_file_operations = {
|
|
.open = proc_sys_open,
|
|
.poll = proc_sys_poll,
|
|
.read = proc_sys_read,
|
|
.write = proc_sys_write,
|
|
.llseek = default_llseek,
|
|
};
|
|
|
|
static const struct file_operations proc_sys_dir_file_operations = {
|
|
.read = generic_read_dir,
|
|
.iterate_shared = proc_sys_readdir,
|
|
.llseek = generic_file_llseek,
|
|
};
|
|
|
|
static const struct inode_operations proc_sys_inode_operations = {
|
|
.permission = proc_sys_permission,
|
|
.setattr = proc_sys_setattr,
|
|
.getattr = proc_sys_getattr,
|
|
};
|
|
|
|
static const struct inode_operations proc_sys_dir_operations = {
|
|
.lookup = proc_sys_lookup,
|
|
.permission = proc_sys_permission,
|
|
.setattr = proc_sys_setattr,
|
|
.getattr = proc_sys_getattr,
|
|
};
|
|
|
|
static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags)
|
|
{
|
|
if (flags & LOOKUP_RCU)
|
|
return -ECHILD;
|
|
return !PROC_I(d_inode(dentry))->sysctl->unregistering;
|
|
}
|
|
|
|
static int proc_sys_delete(const struct dentry *dentry)
|
|
{
|
|
return !!PROC_I(d_inode(dentry))->sysctl->unregistering;
|
|
}
|
|
|
|
static int sysctl_is_seen(struct ctl_table_header *p)
|
|
{
|
|
struct ctl_table_set *set = p->set;
|
|
int res;
|
|
spin_lock(&sysctl_lock);
|
|
if (p->unregistering)
|
|
res = 0;
|
|
else if (!set->is_seen)
|
|
res = 1;
|
|
else
|
|
res = set->is_seen(set);
|
|
spin_unlock(&sysctl_lock);
|
|
return res;
|
|
}
|
|
|
|
static int proc_sys_compare(const struct dentry *dentry,
|
|
unsigned int len, const char *str, const struct qstr *name)
|
|
{
|
|
struct ctl_table_header *head;
|
|
struct inode *inode;
|
|
|
|
/* Although proc doesn't have negative dentries, rcu-walk means
|
|
* that inode here can be NULL */
|
|
/* AV: can it, indeed? */
|
|
inode = d_inode_rcu(dentry);
|
|
if (!inode)
|
|
return 1;
|
|
if (name->len != len)
|
|
return 1;
|
|
if (memcmp(name->name, str, len))
|
|
return 1;
|
|
head = rcu_dereference(PROC_I(inode)->sysctl);
|
|
return !head || !sysctl_is_seen(head);
|
|
}
|
|
|
|
static const struct dentry_operations proc_sys_dentry_operations = {
|
|
.d_revalidate = proc_sys_revalidate,
|
|
.d_delete = proc_sys_delete,
|
|
.d_compare = proc_sys_compare,
|
|
};
|
|
|
|
static struct ctl_dir *find_subdir(struct ctl_dir *dir,
|
|
const char *name, int namelen)
|
|
{
|
|
struct ctl_table_header *head;
|
|
struct ctl_table *entry;
|
|
|
|
entry = find_entry(&head, dir, name, namelen);
|
|
if (!entry)
|
|
return ERR_PTR(-ENOENT);
|
|
if (!S_ISDIR(entry->mode))
|
|
return ERR_PTR(-ENOTDIR);
|
|
return container_of(head, struct ctl_dir, header);
|
|
}
|
|
|
|
static struct ctl_dir *new_dir(struct ctl_table_set *set,
|
|
const char *name, int namelen)
|
|
{
|
|
struct ctl_table *table;
|
|
struct ctl_dir *new;
|
|
struct ctl_node *node;
|
|
char *new_name;
|
|
|
|
new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) +
|
|
sizeof(struct ctl_table)*2 + namelen + 1,
|
|
GFP_KERNEL);
|
|
if (!new)
|
|
return NULL;
|
|
|
|
node = (struct ctl_node *)(new + 1);
|
|
table = (struct ctl_table *)(node + 1);
|
|
new_name = (char *)(table + 2);
|
|
memcpy(new_name, name, namelen);
|
|
new_name[namelen] = '\0';
|
|
table[0].procname = new_name;
|
|
table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO;
|
|
init_header(&new->header, set->dir.header.root, set, node, table);
|
|
|
|
return new;
|
|
}
|
|
|
|
/**
|
|
* get_subdir - find or create a subdir with the specified name.
|
|
* @dir: Directory to create the subdirectory in
|
|
* @name: The name of the subdirectory to find or create
|
|
* @namelen: The length of name
|
|
*
|
|
* Takes a directory with an elevated reference count so we know that
|
|
* if we drop the lock the directory will not go away. Upon success
|
|
* the reference is moved from @dir to the returned subdirectory.
|
|
* Upon error an error code is returned and the reference on @dir is
|
|
* simply dropped.
|
|
*/
|
|
static struct ctl_dir *get_subdir(struct ctl_dir *dir,
|
|
const char *name, int namelen)
|
|
{
|
|
struct ctl_table_set *set = dir->header.set;
|
|
struct ctl_dir *subdir, *new = NULL;
|
|
int err;
|
|
|
|
spin_lock(&sysctl_lock);
|
|
subdir = find_subdir(dir, name, namelen);
|
|
if (!IS_ERR(subdir))
|
|
goto found;
|
|
if (PTR_ERR(subdir) != -ENOENT)
|
|
goto failed;
|
|
|
|
spin_unlock(&sysctl_lock);
|
|
new = new_dir(set, name, namelen);
|
|
spin_lock(&sysctl_lock);
|
|
subdir = ERR_PTR(-ENOMEM);
|
|
if (!new)
|
|
goto failed;
|
|
|
|
/* Was the subdir added while we dropped the lock? */
|
|
subdir = find_subdir(dir, name, namelen);
|
|
if (!IS_ERR(subdir))
|
|
goto found;
|
|
if (PTR_ERR(subdir) != -ENOENT)
|
|
goto failed;
|
|
|
|
/* Nope. Use the our freshly made directory entry. */
|
|
err = insert_header(dir, &new->header);
|
|
subdir = ERR_PTR(err);
|
|
if (err)
|
|
goto failed;
|
|
subdir = new;
|
|
found:
|
|
subdir->header.nreg++;
|
|
failed:
|
|
if (IS_ERR(subdir)) {
|
|
pr_err("sysctl could not get directory: ");
|
|
sysctl_print_dir(dir);
|
|
pr_cont("/%*.*s %ld\n",
|
|
namelen, namelen, name, PTR_ERR(subdir));
|
|
}
|
|
drop_sysctl_table(&dir->header);
|
|
if (new)
|
|
drop_sysctl_table(&new->header);
|
|
spin_unlock(&sysctl_lock);
|
|
return subdir;
|
|
}
|
|
|
|
static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir)
|
|
{
|
|
struct ctl_dir *parent;
|
|
const char *procname;
|
|
if (!dir->header.parent)
|
|
return &set->dir;
|
|
parent = xlate_dir(set, dir->header.parent);
|
|
if (IS_ERR(parent))
|
|
return parent;
|
|
procname = dir->header.ctl_table[0].procname;
|
|
return find_subdir(parent, procname, strlen(procname));
|
|
}
|
|
|
|
static int sysctl_follow_link(struct ctl_table_header **phead,
|
|
struct ctl_table **pentry)
|
|
{
|
|
struct ctl_table_header *head;
|
|
struct ctl_table_root *root;
|
|
struct ctl_table_set *set;
|
|
struct ctl_table *entry;
|
|
struct ctl_dir *dir;
|
|
int ret;
|
|
|
|
ret = 0;
|
|
spin_lock(&sysctl_lock);
|
|
root = (*pentry)->data;
|
|
set = lookup_header_set(root);
|
|
dir = xlate_dir(set, (*phead)->parent);
|
|
if (IS_ERR(dir))
|
|
ret = PTR_ERR(dir);
|
|
else {
|
|
const char *procname = (*pentry)->procname;
|
|
head = NULL;
|
|
entry = find_entry(&head, dir, procname, strlen(procname));
|
|
ret = -ENOENT;
|
|
if (entry && use_table(head)) {
|
|
unuse_table(*phead);
|
|
*phead = head;
|
|
*pentry = entry;
|
|
ret = 0;
|
|
}
|
|
}
|
|
|
|
spin_unlock(&sysctl_lock);
|
|
return ret;
|
|
}
|
|
|
|
static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...)
|
|
{
|
|
struct va_format vaf;
|
|
va_list args;
|
|
|
|
va_start(args, fmt);
|
|
vaf.fmt = fmt;
|
|
vaf.va = &args;
|
|
|
|
pr_err("sysctl table check failed: %s/%s %pV\n",
|
|
path, table->procname, &vaf);
|
|
|
|
va_end(args);
|
|
return -EINVAL;
|
|
}
|
|
|
|
static int sysctl_check_table(const char *path, struct ctl_table *table)
|
|
{
|
|
int err = 0;
|
|
for (; table->procname; table++) {
|
|
if (table->child)
|
|
err = sysctl_err(path, table, "Not a file");
|
|
|
|
if ((table->proc_handler == proc_dostring) ||
|
|
(table->proc_handler == proc_dointvec) ||
|
|
(table->proc_handler == proc_dointvec_minmax) ||
|
|
(table->proc_handler == proc_dointvec_jiffies) ||
|
|
(table->proc_handler == proc_dointvec_userhz_jiffies) ||
|
|
(table->proc_handler == proc_dointvec_ms_jiffies) ||
|
|
(table->proc_handler == proc_doulongvec_minmax) ||
|
|
(table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) {
|
|
if (!table->data)
|
|
err = sysctl_err(path, table, "No data");
|
|
if (!table->maxlen)
|
|
err = sysctl_err(path, table, "No maxlen");
|
|
}
|
|
if (!table->proc_handler)
|
|
err = sysctl_err(path, table, "No proc_handler");
|
|
|
|
if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode)
|
|
err = sysctl_err(path, table, "bogus .mode 0%o",
|
|
table->mode);
|
|
}
|
|
return err;
|
|
}
|
|
|
|
static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table,
|
|
struct ctl_table_root *link_root)
|
|
{
|
|
struct ctl_table *link_table, *entry, *link;
|
|
struct ctl_table_header *links;
|
|
struct ctl_node *node;
|
|
char *link_name;
|
|
int nr_entries, name_bytes;
|
|
|
|
name_bytes = 0;
|
|
nr_entries = 0;
|
|
for (entry = table; entry->procname; entry++) {
|
|
nr_entries++;
|
|
name_bytes += strlen(entry->procname) + 1;
|
|
}
|
|
|
|
links = kzalloc(sizeof(struct ctl_table_header) +
|
|
sizeof(struct ctl_node)*nr_entries +
|
|
sizeof(struct ctl_table)*(nr_entries + 1) +
|
|
name_bytes,
|
|
GFP_KERNEL);
|
|
|
|
if (!links)
|
|
return NULL;
|
|
|
|
node = (struct ctl_node *)(links + 1);
|
|
link_table = (struct ctl_table *)(node + nr_entries);
|
|
link_name = (char *)&link_table[nr_entries + 1];
|
|
|
|
for (link = link_table, entry = table; entry->procname; link++, entry++) {
|
|
int len = strlen(entry->procname) + 1;
|
|
memcpy(link_name, entry->procname, len);
|
|
link->procname = link_name;
|
|
link->mode = S_IFLNK|S_IRWXUGO;
|
|
link->data = link_root;
|
|
link_name += len;
|
|
}
|
|
init_header(links, dir->header.root, dir->header.set, node, link_table);
|
|
links->nreg = nr_entries;
|
|
|
|
return links;
|
|
}
|
|
|
|
static bool get_links(struct ctl_dir *dir,
|
|
struct ctl_table *table, struct ctl_table_root *link_root)
|
|
{
|
|
struct ctl_table_header *head;
|
|
struct ctl_table *entry, *link;
|
|
|
|
/* Are there links available for every entry in table? */
|
|
for (entry = table; entry->procname; entry++) {
|
|
const char *procname = entry->procname;
|
|
link = find_entry(&head, dir, procname, strlen(procname));
|
|
if (!link)
|
|
return false;
|
|
if (S_ISDIR(link->mode) && S_ISDIR(entry->mode))
|
|
continue;
|
|
if (S_ISLNK(link->mode) && (link->data == link_root))
|
|
continue;
|
|
return false;
|
|
}
|
|
|
|
/* The checks passed. Increase the registration count on the links */
|
|
for (entry = table; entry->procname; entry++) {
|
|
const char *procname = entry->procname;
|
|
link = find_entry(&head, dir, procname, strlen(procname));
|
|
head->nreg++;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
static int insert_links(struct ctl_table_header *head)
|
|
{
|
|
struct ctl_table_set *root_set = &sysctl_table_root.default_set;
|
|
struct ctl_dir *core_parent = NULL;
|
|
struct ctl_table_header *links;
|
|
int err;
|
|
|
|
if (head->set == root_set)
|
|
return 0;
|
|
|
|
core_parent = xlate_dir(root_set, head->parent);
|
|
if (IS_ERR(core_parent))
|
|
return 0;
|
|
|
|
if (get_links(core_parent, head->ctl_table, head->root))
|
|
return 0;
|
|
|
|
core_parent->header.nreg++;
|
|
spin_unlock(&sysctl_lock);
|
|
|
|
links = new_links(core_parent, head->ctl_table, head->root);
|
|
|
|
spin_lock(&sysctl_lock);
|
|
err = -ENOMEM;
|
|
if (!links)
|
|
goto out;
|
|
|
|
err = 0;
|
|
if (get_links(core_parent, head->ctl_table, head->root)) {
|
|
kfree(links);
|
|
goto out;
|
|
}
|
|
|
|
err = insert_header(core_parent, links);
|
|
if (err)
|
|
kfree(links);
|
|
out:
|
|
drop_sysctl_table(&core_parent->header);
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* __register_sysctl_table - register a leaf sysctl table
|
|
* @set: Sysctl tree to register on
|
|
* @path: The path to the directory the sysctl table is in.
|
|
* @table: the top-level table structure
|
|
*
|
|
* Register a sysctl table hierarchy. @table should be a filled in ctl_table
|
|
* array. A completely 0 filled entry terminates the table.
|
|
*
|
|
* The members of the &struct ctl_table structure are used as follows:
|
|
*
|
|
* procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
|
|
* enter a sysctl file
|
|
*
|
|
* data - a pointer to data for use by proc_handler
|
|
*
|
|
* maxlen - the maximum size in bytes of the data
|
|
*
|
|
* mode - the file permissions for the /proc/sys file
|
|
*
|
|
* child - must be %NULL.
|
|
*
|
|
* proc_handler - the text handler routine (described below)
|
|
*
|
|
* extra1, extra2 - extra pointers usable by the proc handler routines
|
|
*
|
|
* Leaf nodes in the sysctl tree will be represented by a single file
|
|
* under /proc; non-leaf nodes will be represented by directories.
|
|
*
|
|
* There must be a proc_handler routine for any terminal nodes.
|
|
* Several default handlers are available to cover common cases -
|
|
*
|
|
* proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
|
|
* proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
|
|
* proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
|
|
*
|
|
* It is the handler's job to read the input buffer from user memory
|
|
* and process it. The handler should return 0 on success.
|
|
*
|
|
* This routine returns %NULL on a failure to register, and a pointer
|
|
* to the table header on success.
|
|
*/
|
|
struct ctl_table_header *__register_sysctl_table(
|
|
struct ctl_table_set *set,
|
|
const char *path, struct ctl_table *table)
|
|
{
|
|
struct ctl_table_root *root = set->dir.header.root;
|
|
struct ctl_table_header *header;
|
|
const char *name, *nextname;
|
|
struct ctl_dir *dir;
|
|
struct ctl_table *entry;
|
|
struct ctl_node *node;
|
|
int nr_entries = 0;
|
|
|
|
for (entry = table; entry->procname; entry++)
|
|
nr_entries++;
|
|
|
|
header = kzalloc(sizeof(struct ctl_table_header) +
|
|
sizeof(struct ctl_node)*nr_entries, GFP_KERNEL);
|
|
if (!header)
|
|
return NULL;
|
|
|
|
node = (struct ctl_node *)(header + 1);
|
|
init_header(header, root, set, node, table);
|
|
if (sysctl_check_table(path, table))
|
|
goto fail;
|
|
|
|
spin_lock(&sysctl_lock);
|
|
dir = &set->dir;
|
|
/* Reference moved down the diretory tree get_subdir */
|
|
dir->header.nreg++;
|
|
spin_unlock(&sysctl_lock);
|
|
|
|
/* Find the directory for the ctl_table */
|
|
for (name = path; name; name = nextname) {
|
|
int namelen;
|
|
nextname = strchr(name, '/');
|
|
if (nextname) {
|
|
namelen = nextname - name;
|
|
nextname++;
|
|
} else {
|
|
namelen = strlen(name);
|
|
}
|
|
if (namelen == 0)
|
|
continue;
|
|
|
|
dir = get_subdir(dir, name, namelen);
|
|
if (IS_ERR(dir))
|
|
goto fail;
|
|
}
|
|
|
|
spin_lock(&sysctl_lock);
|
|
if (insert_header(dir, header))
|
|
goto fail_put_dir_locked;
|
|
|
|
drop_sysctl_table(&dir->header);
|
|
spin_unlock(&sysctl_lock);
|
|
|
|
return header;
|
|
|
|
fail_put_dir_locked:
|
|
drop_sysctl_table(&dir->header);
|
|
spin_unlock(&sysctl_lock);
|
|
fail:
|
|
kfree(header);
|
|
dump_stack();
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* register_sysctl - register a sysctl table
|
|
* @path: The path to the directory the sysctl table is in.
|
|
* @table: the table structure
|
|
*
|
|
* Register a sysctl table. @table should be a filled in ctl_table
|
|
* array. A completely 0 filled entry terminates the table.
|
|
*
|
|
* See __register_sysctl_table for more details.
|
|
*/
|
|
struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table)
|
|
{
|
|
return __register_sysctl_table(&sysctl_table_root.default_set,
|
|
path, table);
|
|
}
|
|
EXPORT_SYMBOL(register_sysctl);
|
|
|
|
static char *append_path(const char *path, char *pos, const char *name)
|
|
{
|
|
int namelen;
|
|
namelen = strlen(name);
|
|
if (((pos - path) + namelen + 2) >= PATH_MAX)
|
|
return NULL;
|
|
memcpy(pos, name, namelen);
|
|
pos[namelen] = '/';
|
|
pos[namelen + 1] = '\0';
|
|
pos += namelen + 1;
|
|
return pos;
|
|
}
|
|
|
|
static int count_subheaders(struct ctl_table *table)
|
|
{
|
|
int has_files = 0;
|
|
int nr_subheaders = 0;
|
|
struct ctl_table *entry;
|
|
|
|
/* special case: no directory and empty directory */
|
|
if (!table || !table->procname)
|
|
return 1;
|
|
|
|
for (entry = table; entry->procname; entry++) {
|
|
if (entry->child)
|
|
nr_subheaders += count_subheaders(entry->child);
|
|
else
|
|
has_files = 1;
|
|
}
|
|
return nr_subheaders + has_files;
|
|
}
|
|
|
|
static int register_leaf_sysctl_tables(const char *path, char *pos,
|
|
struct ctl_table_header ***subheader, struct ctl_table_set *set,
|
|
struct ctl_table *table)
|
|
{
|
|
struct ctl_table *ctl_table_arg = NULL;
|
|
struct ctl_table *entry, *files;
|
|
int nr_files = 0;
|
|
int nr_dirs = 0;
|
|
int err = -ENOMEM;
|
|
|
|
for (entry = table; entry->procname; entry++) {
|
|
if (entry->child)
|
|
nr_dirs++;
|
|
else
|
|
nr_files++;
|
|
}
|
|
|
|
files = table;
|
|
/* If there are mixed files and directories we need a new table */
|
|
if (nr_dirs && nr_files) {
|
|
struct ctl_table *new;
|
|
files = kzalloc(sizeof(struct ctl_table) * (nr_files + 1),
|
|
GFP_KERNEL);
|
|
if (!files)
|
|
goto out;
|
|
|
|
ctl_table_arg = files;
|
|
for (new = files, entry = table; entry->procname; entry++) {
|
|
if (entry->child)
|
|
continue;
|
|
*new = *entry;
|
|
new++;
|
|
}
|
|
}
|
|
|
|
/* Register everything except a directory full of subdirectories */
|
|
if (nr_files || !nr_dirs) {
|
|
struct ctl_table_header *header;
|
|
header = __register_sysctl_table(set, path, files);
|
|
if (!header) {
|
|
kfree(ctl_table_arg);
|
|
goto out;
|
|
}
|
|
|
|
/* Remember if we need to free the file table */
|
|
header->ctl_table_arg = ctl_table_arg;
|
|
**subheader = header;
|
|
(*subheader)++;
|
|
}
|
|
|
|
/* Recurse into the subdirectories. */
|
|
for (entry = table; entry->procname; entry++) {
|
|
char *child_pos;
|
|
|
|
if (!entry->child)
|
|
continue;
|
|
|
|
err = -ENAMETOOLONG;
|
|
child_pos = append_path(path, pos, entry->procname);
|
|
if (!child_pos)
|
|
goto out;
|
|
|
|
err = register_leaf_sysctl_tables(path, child_pos, subheader,
|
|
set, entry->child);
|
|
pos[0] = '\0';
|
|
if (err)
|
|
goto out;
|
|
}
|
|
err = 0;
|
|
out:
|
|
/* On failure our caller will unregister all registered subheaders */
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* __register_sysctl_paths - register a sysctl table hierarchy
|
|
* @set: Sysctl tree to register on
|
|
* @path: The path to the directory the sysctl table is in.
|
|
* @table: the top-level table structure
|
|
*
|
|
* Register a sysctl table hierarchy. @table should be a filled in ctl_table
|
|
* array. A completely 0 filled entry terminates the table.
|
|
*
|
|
* See __register_sysctl_table for more details.
|
|
*/
|
|
struct ctl_table_header *__register_sysctl_paths(
|
|
struct ctl_table_set *set,
|
|
const struct ctl_path *path, struct ctl_table *table)
|
|
{
|
|
struct ctl_table *ctl_table_arg = table;
|
|
int nr_subheaders = count_subheaders(table);
|
|
struct ctl_table_header *header = NULL, **subheaders, **subheader;
|
|
const struct ctl_path *component;
|
|
char *new_path, *pos;
|
|
|
|
pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL);
|
|
if (!new_path)
|
|
return NULL;
|
|
|
|
pos[0] = '\0';
|
|
for (component = path; component->procname; component++) {
|
|
pos = append_path(new_path, pos, component->procname);
|
|
if (!pos)
|
|
goto out;
|
|
}
|
|
while (table->procname && table->child && !table[1].procname) {
|
|
pos = append_path(new_path, pos, table->procname);
|
|
if (!pos)
|
|
goto out;
|
|
table = table->child;
|
|
}
|
|
if (nr_subheaders == 1) {
|
|
header = __register_sysctl_table(set, new_path, table);
|
|
if (header)
|
|
header->ctl_table_arg = ctl_table_arg;
|
|
} else {
|
|
header = kzalloc(sizeof(*header) +
|
|
sizeof(*subheaders)*nr_subheaders, GFP_KERNEL);
|
|
if (!header)
|
|
goto out;
|
|
|
|
subheaders = (struct ctl_table_header **) (header + 1);
|
|
subheader = subheaders;
|
|
header->ctl_table_arg = ctl_table_arg;
|
|
|
|
if (register_leaf_sysctl_tables(new_path, pos, &subheader,
|
|
set, table))
|
|
goto err_register_leaves;
|
|
}
|
|
|
|
out:
|
|
kfree(new_path);
|
|
return header;
|
|
|
|
err_register_leaves:
|
|
while (subheader > subheaders) {
|
|
struct ctl_table_header *subh = *(--subheader);
|
|
struct ctl_table *table = subh->ctl_table_arg;
|
|
unregister_sysctl_table(subh);
|
|
kfree(table);
|
|
}
|
|
kfree(header);
|
|
header = NULL;
|
|
goto out;
|
|
}
|
|
|
|
/**
|
|
* register_sysctl_table_path - register a sysctl table hierarchy
|
|
* @path: The path to the directory the sysctl table is in.
|
|
* @table: the top-level table structure
|
|
*
|
|
* Register a sysctl table hierarchy. @table should be a filled in ctl_table
|
|
* array. A completely 0 filled entry terminates the table.
|
|
*
|
|
* See __register_sysctl_paths for more details.
|
|
*/
|
|
struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
|
|
struct ctl_table *table)
|
|
{
|
|
return __register_sysctl_paths(&sysctl_table_root.default_set,
|
|
path, table);
|
|
}
|
|
EXPORT_SYMBOL(register_sysctl_paths);
|
|
|
|
/**
|
|
* register_sysctl_table - register a sysctl table hierarchy
|
|
* @table: the top-level table structure
|
|
*
|
|
* Register a sysctl table hierarchy. @table should be a filled in ctl_table
|
|
* array. A completely 0 filled entry terminates the table.
|
|
*
|
|
* See register_sysctl_paths for more details.
|
|
*/
|
|
struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
|
|
{
|
|
static const struct ctl_path null_path[] = { {} };
|
|
|
|
return register_sysctl_paths(null_path, table);
|
|
}
|
|
EXPORT_SYMBOL(register_sysctl_table);
|
|
|
|
static void put_links(struct ctl_table_header *header)
|
|
{
|
|
struct ctl_table_set *root_set = &sysctl_table_root.default_set;
|
|
struct ctl_table_root *root = header->root;
|
|
struct ctl_dir *parent = header->parent;
|
|
struct ctl_dir *core_parent;
|
|
struct ctl_table *entry;
|
|
|
|
if (header->set == root_set)
|
|
return;
|
|
|
|
core_parent = xlate_dir(root_set, parent);
|
|
if (IS_ERR(core_parent))
|
|
return;
|
|
|
|
for (entry = header->ctl_table; entry->procname; entry++) {
|
|
struct ctl_table_header *link_head;
|
|
struct ctl_table *link;
|
|
const char *name = entry->procname;
|
|
|
|
link = find_entry(&link_head, core_parent, name, strlen(name));
|
|
if (link &&
|
|
((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) ||
|
|
(S_ISLNK(link->mode) && (link->data == root)))) {
|
|
drop_sysctl_table(link_head);
|
|
}
|
|
else {
|
|
pr_err("sysctl link missing during unregister: ");
|
|
sysctl_print_dir(parent);
|
|
pr_cont("/%s\n", name);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void drop_sysctl_table(struct ctl_table_header *header)
|
|
{
|
|
struct ctl_dir *parent = header->parent;
|
|
|
|
if (--header->nreg)
|
|
return;
|
|
|
|
put_links(header);
|
|
start_unregistering(header);
|
|
if (!--header->count)
|
|
kfree_rcu(header, rcu);
|
|
|
|
if (parent)
|
|
drop_sysctl_table(&parent->header);
|
|
}
|
|
|
|
/**
|
|
* unregister_sysctl_table - unregister a sysctl table hierarchy
|
|
* @header: the header returned from register_sysctl_table
|
|
*
|
|
* Unregisters the sysctl table and all children. proc entries may not
|
|
* actually be removed until they are no longer used by anyone.
|
|
*/
|
|
void unregister_sysctl_table(struct ctl_table_header * header)
|
|
{
|
|
int nr_subheaders;
|
|
might_sleep();
|
|
|
|
if (header == NULL)
|
|
return;
|
|
|
|
nr_subheaders = count_subheaders(header->ctl_table_arg);
|
|
if (unlikely(nr_subheaders > 1)) {
|
|
struct ctl_table_header **subheaders;
|
|
int i;
|
|
|
|
subheaders = (struct ctl_table_header **)(header + 1);
|
|
for (i = nr_subheaders -1; i >= 0; i--) {
|
|
struct ctl_table_header *subh = subheaders[i];
|
|
struct ctl_table *table = subh->ctl_table_arg;
|
|
unregister_sysctl_table(subh);
|
|
kfree(table);
|
|
}
|
|
kfree(header);
|
|
return;
|
|
}
|
|
|
|
spin_lock(&sysctl_lock);
|
|
drop_sysctl_table(header);
|
|
spin_unlock(&sysctl_lock);
|
|
}
|
|
EXPORT_SYMBOL(unregister_sysctl_table);
|
|
|
|
void setup_sysctl_set(struct ctl_table_set *set,
|
|
struct ctl_table_root *root,
|
|
int (*is_seen)(struct ctl_table_set *))
|
|
{
|
|
memset(set, 0, sizeof(*set));
|
|
set->is_seen = is_seen;
|
|
init_header(&set->dir.header, root, set, NULL, root_table);
|
|
}
|
|
|
|
void retire_sysctl_set(struct ctl_table_set *set)
|
|
{
|
|
WARN_ON(!RB_EMPTY_ROOT(&set->dir.root));
|
|
}
|
|
|
|
int __init proc_sys_init(void)
|
|
{
|
|
struct proc_dir_entry *proc_sys_root;
|
|
|
|
proc_sys_root = proc_mkdir("sys", NULL);
|
|
proc_sys_root->proc_iops = &proc_sys_dir_operations;
|
|
proc_sys_root->proc_fops = &proc_sys_dir_file_operations;
|
|
proc_sys_root->nlink = 0;
|
|
|
|
return sysctl_init();
|
|
}
|