SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
char __user *, buf, int, bufsiz)
{
struct path path;
int error;
if (bufsiz <= 0)
return -EINVAL;
error = user_path_at(dfd, pathname, 0, &path);
if (!error) {
struct inode *inode = path.dentry->d_inode;
error = -EINVAL;
if (inode->i_op->readlink) {
error = security_inode_readlink(path.dentry);
if (!error) {
touch_atime(path.mnt, path.dentry);
error = inode->i_op->readlink(path.dentry,
buf, bufsiz);
}
}
path_put(&path);
}
return error;
}
SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
char __user *, buf, int, bufsiz)
{
struct path path;
int error;
int empty = 0;
unsigned int lookup_flags = LOOKUP_EMPTY;
if (bufsiz <= 0)
return -EINVAL;
retry:
error = user_path_at_empty(dfd, pathname, lookup_flags, &path, &empty);
if (!error) {
struct inode *inode = d_backing_inode(path.dentry);
error = empty ? -ENOENT : -EINVAL;
if (inode->i_op->readlink) {
error = security_inode_readlink(path.dentry);
if (!error) {
touch_atime(&path);
error = inode->i_op->readlink(path.dentry,
buf, bufsiz);
}
}
path_put(&path);
if (retry_estale(error, lookup_flags)) {
lookup_flags |= LOOKUP_REVAL;
goto retry;
}
}
return error;
}
asmlinkage long sys_readlinkat(int dfd, const char __user *path,
char __user *buf, int bufsiz)
{
struct nameidata nd;
int error;
if (bufsiz <= 0)
return -EINVAL;
error = __user_walk_fd(dfd, path, 0, &nd);
if (!error) {
struct inode * inode = nd.dentry->d_inode;
error = -EINVAL;
if (inode->i_op && inode->i_op->readlink) {
error = security_inode_readlink(nd.dentry);
if (!error) {
touch_atime(nd.mnt, nd.dentry);
error = inode->i_op->readlink(nd.dentry, buf, bufsiz);
}
}
path_release(&nd);
}
return error;
}
SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname,
char __user *, buf, int, bufsiz)
{
struct path path;
int error;
int empty = 0;
if (bufsiz <= 0)
return -EINVAL;
error = user_path_at_empty(dfd, pathname, LOOKUP_EMPTY, &path, &empty);
if (!error) {
struct inode *inode = path.dentry->d_inode;
error = empty ? -ENOENT : -EINVAL;
if (inode->i_op->readlink) {
error = security_inode_readlink(path.dentry);
if (!error) {
touch_atime(&path);
error = inode->i_op->readlink(path.dentry,
buf, bufsiz);
}
}
path_put(&path);
}
return error;
}
asmlinkage long sys_readlink(const char * path, char * buf, int bufsiz)
{
struct nameidata nd;
int error;
if (bufsiz <= 0)
return -EINVAL;
error = user_path_walk_link(path, &nd);
if (!error) {
struct inode * inode = nd.dentry->d_inode;
error = -EINVAL;
if (inode->i_op && inode->i_op->readlink &&
!(error = do_revalidate(nd.dentry))) {
if (!(error = security_inode_readlink(nd.dentry))) {
UPDATE_ATIME(inode);
error = inode->i_op->readlink(nd.dentry, buf, bufsiz);
}
}
path_release(&nd);
}
return error;
}
