/*
* Copyright (C) 2007 Red Hat. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
#include <linux/posix_acl.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include "ctree.h"
#include "btrfs_inode.h"
#include "xattr.h"
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
static struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
{
int size;
const char *name;
char *value = NULL;
struct posix_acl *acl;
acl = get_cached_acl(inode, type);
if (acl != ACL_NOT_CACHED)
return acl;
switch (type) {
case ACL_TYPE_ACCESS:
name = POSIX_ACL_XATTR_ACCESS;
break;
case ACL_TYPE_DEFAULT:
name = POSIX_ACL_XATTR_DEFAULT;
break;
default:
BUG();
}
size = __btrfs_getxattr(inode, name, "", 0);
if (size > 0) {
value = kzalloc(size, GFP_NOFS);
if (!value)
return ERR_PTR(-ENOMEM);
size = __btrfs_getxattr(inode, name, value, size);
if (size > 0) {
acl = posix_acl_from_xattr(value, size);
if (IS_ERR(acl)) {
kfree(value);
return acl;
}
set_cached_acl(inode, type, acl);
}
kfree(value);
} else if (size == -ENOENT || size == -ENODATA || size == 0) {
/* FIXME, who returns -ENOENT? I think nobody */
acl = NULL;
set_cached_acl(inode, type, acl);
} else {
acl = ERR_PTR(-EIO);
}
return acl;
}
static int btrfs_xattr_acl_get(struct dentry *dentry, const char *name,
void *value, size_t size, int type)
{
struct posix_acl *acl;
int ret = 0;
acl = btrfs_get_acl(dentry->d_inode, type);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl == NULL)
return -ENODATA;
ret = posix_acl_to_xattr(acl, value, size);
posix_acl_release(acl);
return ret;
}
/*
* Needs to be called with fs_mutex held
*/
static int btrfs_set_acl(struct btrfs_trans_handle *trans,
struct inode *inode, struct posix_acl *acl, int type)
{
int ret, size = 0;
const char *name;
char *value = NULL;
mode_t mode;
if (acl) {
ret = posix_acl_valid(acl);
if (ret < 0)
return ret;
ret = 0;
}
switch (type) {
case ACL_TYPE_ACCESS:
mode = inode->i_mode;
name = POSIX_ACL_XATTR_ACCESS;
if (acl) {
ret = posix_acl_equiv_mode(acl, &mode);
if (ret < 0)
return ret;
inode->i_mode = mode;
}
ret = 0;
break;
case ACL_TYPE_DEFAULT:
if (!S_ISDIR(inode->i_mode))
return acl ? -EINVAL : 0;
name = POSIX_ACL_XATTR_DEFAULT;
break;
default:
return -EINVAL;
}
if (acl) {
size = posix_acl_xattr_size(acl->a_count);
value = kmalloc(size, GFP_NOFS);
if (!value) {
ret = -ENOMEM;
goto out;
}
ret = posix_acl_to_xattr(acl, value, size);
if (ret < 0)
goto out;
}
ret = __btrfs_setxattr(trans, inode, name, value, size, 0);
out:
kfree(value);
if (!ret)
set_cached_acl(inode, type, acl);
return ret;
}
static int btrfs_xattr_acl_set(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags, int type)
{
int ret;
struct posix_acl *acl = NULL;
if (!is_owner_or_cap(dentry->d_inode))
return -EPERM;
if (!IS_POSIXACL(dentry->d_inode))
return -EOPNOTSUPP;
if (value) {
acl = posix_acl_from_xattr(value, size);
if (acl == NULL) {
value = NULL;
size = 0;
} else if (IS_ERR(acl)) {
return PTR_ERR(acl);
}
}
ret = btrfs_set_acl(NULL, dentry->d_inode, acl, type);
posix_acl_release(acl);
return ret;
}
int btrfs_check_acl(struct inode *inode, int mask, unsigned int flags)
{
int error = -EAGAIN;
if (flags & IPERM_FLAG_RCU) {
if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
error = -ECHILD;
} else {
struct posix_acl *acl;
acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl) {
error = posix_acl_permission(inode, acl, mask);
posix_acl_release(acl);
}
}
return error;
}
/*
* btrfs_init_acl is already generally called under fs_mutex, so the locking
* stuff has been fixed to work with that. If the locking stuff changes, we
* need to re-evaluate the acl locking stuff.
*/
int btrfs_init_acl(struct btrfs_trans_handle *trans,
struct inode *inode, struct inode *dir)
{
struct posix_acl *acl = NULL;
int ret = 0;
/* this happens with subvols */
if (!dir)
return 0;
if (!S_ISLNK(inode->i_mode)) {
if (IS_POSIXACL(dir)) {
acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT);
if (IS_ERR(acl))
return PTR_ERR(acl);
}
if (!acl)
inode->i_mode &= ~current_umask();
}
if (IS_POSIXACL(dir) && acl) {
struct posix_acl *clone;
mode_t mode;
if (S_ISDIR(inode->i_mode)) {
ret = btrfs_set_acl(trans, inode, acl,
ACL_TYPE_DEFAULT);
if (ret)
goto failed;
}
clone = posix_acl_clone(acl, GFP_NOFS);
ret = -ENOMEM;
if (!clone)
goto failed;
mode = inode->i_mode;
ret = posix_acl_create_masq(clone, &mode);
if (ret >= 0) {
inode->i_mode = mode;
if (ret > 0) {
/* we need an acl */
ret = btrfs_set_acl(trans, inode, clone,
ACL_TYPE_ACCESS);
}
}
posix_acl_release(clone);
}
failed:
posix_acl_release(acl);
return ret;
}
int btrfs_acl_chmod(struct inode *inode)
{
struct posix_acl *acl, *clone;
int ret = 0;
if (S_ISLNK(inode->i_mode))
return -EOPNOTSUPP;
if (!IS_POSIXACL(inode))
return 0;
acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl) || !acl)
return PTR_ERR(acl);
clone = posix_acl_clone(acl, GFP_KERNEL);
posix_acl_release(acl);
if (!clone)
return -ENOMEM;
ret = posix_acl_chmod_masq(clone, inode->i_mode);
if (!ret)
ret = btrfs_set_acl(NULL, inode, clone, ACL_TYPE_ACCESS);
posix_acl_release(clone);
return ret;
}
const struct xattr_handler btrfs_xattr_acl_default_handler = {
.prefix = POSIX_ACL_XATTR_DEFAULT,
.flags = ACL_TYPE_DEFAULT,
.get = btrfs_xattr_acl_get,
.set = btrfs_xattr_acl_set,
};
const struct xattr_handler btrfs_xattr_acl_access_handler = {
.prefix = POSIX_ACL_XATTR_ACCESS,
.flags = ACL_TYPE_ACCESS,
.get = btrfs_xattr_acl_get,
.set = btrfs_xattr_acl_set,
};
#else /* CONFIG_BTRFS_FS_POSIX_ACL */
int btrfs_acl_chmod(struct inode *inode)
{
return 0;
}
int btrfs_init_acl(struct btrfs_trans_handle *trans,
struct inode *inode, struct inode *dir)
{
return 0;
}
#endif /* CONFIG_BTRFS_FS_POSIX_ACL */
