static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry,
struct nameidata *nd)
{
struct ctl_table_header *head = grab_header(dir);
struct ctl_table *table = PROC_I(dir)->sysctl_entry;
struct ctl_table_header *h = NULL;
struct qstr *name = &dentry->d_name;
struct ctl_table *p;
struct inode *inode;
struct dentry *err = ERR_PTR(-ENOENT);
if (IS_ERR(head))
return ERR_CAST(head);
if (table && !table->child) {
WARN_ON(1);
goto out;
}
table = table ? table->child : head->ctl_table;
p = find_in_table(table, name);
if (!p) {
for (h = sysctl_head_next(NULL); h; h = sysctl_head_next(h)) {
if (h->attached_to != table)
continue;
p = find_in_table(h->attached_by, name);
if (p)
break;
}
}
if (!p)
goto out;
err = ERR_PTR(-ENOMEM);
inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
if (h)
sysctl_head_finish(h);
if (!inode)
goto out;
err = NULL;
dentry->d_op = &proc_sys_dentry_operations;
d_add(dentry, inode);
out:
sysctl_head_finish(head);
return err;
}
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->root, table, mask & ~MAY_NOT_BLOCK);
sysctl_head_finish(head);
return error;
}
static unsigned int proc_sys_poll(struct file *filp, poll_table *wait)
{
struct inode *inode = filp->f_path.dentry->d_inode;
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 ssize_t proc_sys_call_handler(struct file *filp, void __user *buf,
size_t count, loff_t *ppos, int write)
{
struct inode *inode = filp->f_path.dentry->d_inode;
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->root, 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 int proc_sys_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
{
struct inode *inode = dentry->d_inode;
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 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 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 = grab_header(inode);
struct ctl_table *table = PROC_I(inode)->sysctl_entry;
int error;
if (IS_ERR(head))
return PTR_ERR(head);
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->root, table, mask);
sysctl_head_finish(head);
return error;
}
static struct ctl_table *sysctl_check_lookup(struct nsproxy *namespaces,
struct ctl_table *table)
{
struct ctl_table_header *head;
struct ctl_table *ref, *test;
int depth, cur_depth;
depth = sysctl_depth(table);
for (head = __sysctl_head_next(namespaces, NULL); head;
head = __sysctl_head_next(namespaces, head)) {
cur_depth = depth;
ref = head->ctl_table;
repeat:
test = sysctl_parent(table, cur_depth);
for (; ref->procname; ref++) {
int match = 0;
if (cur_depth && !ref->child)
continue;
if (test->procname && ref->procname &&
(strcmp(test->procname, ref->procname) == 0))
match++;
if (match) {
if (cur_depth != 0) {
cur_depth--;
ref = ref->child;
goto repeat;
}
goto out;
}
}
}
ref = NULL;
out:
sysctl_head_finish(head);
return ref;
}
