/*
* Copyright (c) 2008, Christoph Hellwig
* 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 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would 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 the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "xfs.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_acl.h"
#include "xfs_attr.h"
#include "xfs_trace.h"
#include <linux/slab.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
/*
* Locking scheme:
* - all ACL updates are protected by inode->i_mutex, which is taken before
* calling into this file.
*/
STATIC struct posix_acl *
xfs_acl_from_disk(
struct xfs_acl *aclp,
int max_entries)
{
struct posix_acl_entry *acl_e;
struct posix_acl *acl;
struct xfs_acl_entry *ace;
unsigned int count, i;
count = be32_to_cpu(aclp->acl_cnt);
if (count > max_entries)
return ERR_PTR(-EFSCORRUPTED);
acl = posix_acl_alloc(count, GFP_KERNEL);
if (!acl)
return ERR_PTR(-ENOMEM);
for (i = 0; i < count; i++) {
acl_e = &acl->a_entries[i];
ace = &aclp->acl_entry[i];
/*
* The tag is 32 bits on disk and 16 bits in core.
*
* Because every access to it goes through the core
* format first this is not a problem.
*/
acl_e->e_tag = be32_to_cpu(ace->ae_tag);
acl_e->e_perm = be16_to_cpu(ace->ae_perm);
switch (acl_e->e_tag) {
case ACL_USER:
acl_e->e_uid = xfs_uid_to_kuid(be32_to_cpu(ace->ae_id));
break;
case ACL_GROUP:
acl_e->e_gid = xfs_gid_to_kgid(be32_to_cpu(ace->ae_id));
break;
case ACL_USER_OBJ:
case ACL_GROUP_OBJ:
case ACL_MASK:
case ACL_OTHER:
break;
default:
goto fail;
}
}
return acl;
fail:
posix_acl_release(acl);
return ERR_PTR(-EINVAL);
}
STATIC void
xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
{
const struct posix_acl_entry *acl_e;
struct xfs_acl_entry *ace;
int i;
aclp->acl_cnt = cpu_to_be32(acl->a_count);
for (i = 0; i < acl->a_count; i++) {
ace = &aclp->acl_entry[i];
acl_e = &acl->a_entries[i];
ace->ae_tag = cpu_to_be32(acl_e->e_tag);
switch (acl_e->e_tag) {
case ACL_USER:
ace->ae_id = cpu_to_be32(xfs_kuid_to_uid(acl_e->e_uid));
break;
case ACL_GROUP:
ace->ae_id = cpu_to_be32(xfs_kgid_to_gid(acl_e->e_gid));
break;
default:
ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
break;
}
ace->ae_perm = cpu_to_be16(acl_e->e_perm);
}
}
struct posix_acl *
xfs_get_acl(struct inode *inode, int type)
{
struct xfs_inode *ip = XFS_I(inode);
struct posix_acl *acl = NULL;
struct xfs_acl *xfs_acl;
unsigned char *ea_name;
int error;
int len;
trace_xfs_get_acl(ip);
switch (type) {
case ACL_TYPE_ACCESS:
ea_name = SGI_ACL_FILE;
break;
case ACL_TYPE_DEFAULT:
ea_name = SGI_ACL_DEFAULT;
break;
default:
BUG();
}
/*
* If we have a cached ACLs value just return it, not need to
* go out to the disk.
*/
len = XFS_ACL_MAX_SIZE(ip->i_mount);
xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
if (!xfs_acl)
return ERR_PTR(-ENOMEM);
error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
&len, ATTR_ROOT);
if (error) {
/*
* If the attribute doesn't exist make sure we have a negative
* cache entry, for any other error assume it is transient and
* leave the cache entry as ACL_NOT_CACHED.
*/
if (error == -ENOATTR)
goto out_update_cache;
goto out;
}
acl = xfs_acl_from_disk(xfs_acl, XFS_ACL_MAX_ENTRIES(ip->i_mount));
if (IS_ERR(acl))
goto out;
out_update_cache:
set_cached_acl(inode, type, acl);
out:
kmem_free(xfs_acl);
return acl;
}
STATIC int
__xfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
{
struct xfs_inode *ip = XFS_I(inode);
unsigned char *ea_name;
int error;
switch (type) {
case ACL_TYPE_ACCESS:
ea_name = SGI_ACL_FILE;
break;
case ACL_TYPE_DEFAULT:
if (!S_ISDIR(inode->i_mode))
return acl ? -EACCES : 0;
ea_name = SGI_ACL_DEFAULT;
break;
default:
return -EINVAL;
}
if (acl) {
struct xfs_acl *xfs_acl;
int len = XFS_ACL_MAX_SIZE(ip->i_mount);
xfs_acl = kmem_zalloc_large(len, KM_SLEEP);
if (!xfs_acl)
return -ENOMEM;
xfs_acl_to_disk(xfs_acl, acl);
/* subtract away the unused acl entries */
len -= sizeof(struct xfs_acl_entry) *
(XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);
error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
len, ATTR_ROOT);
kmem_free(xfs_acl);
} else {
/*
* A NULL ACL argument means we want to remove the ACL.
*/
error = xfs_attr_remove(ip, ea_name, ATTR_ROOT);
/*
* If the attribute didn't exist to start with that's fine.
*/
if (error == -ENOATTR)
error = 0;
}
if (!error)
set_cached_acl(inode, type, acl);
return error;
}
static int
xfs_set_mode(struct inode *inode, umode_t mode)
{
int error = 0;
if (mode != inode->i_mode) {
struct iattr iattr;
iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
iattr.ia_mode = mode;
iattr.ia_ctime = current_fs_time(inode->i_sb);
error = xfs_setattr_nonsize(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
}
return error;
}
static int
xfs_acl_exists(struct inode *inode, unsigned char *name)
{
int len = XFS_ACL_MAX_SIZE(XFS_M(inode->i_sb));
return (xfs_attr_get(XFS_I(inode), name, NULL, &len,
ATTR_ROOT|ATTR_KERNOVAL) == 0);
}
int
posix_acl_access_exists(struct inode *inode)
{
return xfs_acl_exists(inode, SGI_ACL_FILE);
}
int
posix_acl_default_exists(struct inode *inode)
{
if (!S_ISDIR(inode->i_mode))
return 0;
return xfs_acl_exists(inode, SGI_ACL_DEFAULT);
}
int
xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
int error = 0;
if (!acl)
goto set_acl;
error = -E2BIG;
if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
return error;
if (type == ACL_TYPE_ACCESS) {
umode_t mode = inode->i_mode;
error = posix_acl_equiv_mode(acl, &mode);
if (error <= 0) {
acl = NULL;
if (error < 0)
return error;
}
error = xfs_set_mode(inode, mode);
if (error)
return error;
}
set_acl:
return __xfs_set_acl(inode, type, acl);
}
