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/*
* Copyright IBM Corporation, 2010
* Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of version 2.1 of the GNU Lesser 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.
*
*/
#include <linux/module.h>
#include <linux/fs.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/posix_acl_xattr.h>
#include "xattr.h"
#include "acl.h"
#include "v9fs_vfs.h"
static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, char *name)
{
ssize_t size;
void *value = NULL;
struct posix_acl *acl = NULL;;
size = v9fs_fid_xattr_get(fid, name, NULL, 0);
if (size > 0) {
value = kzalloc(size, GFP_NOFS);
if (!value)
return ERR_PTR(-ENOMEM);
size = v9fs_fid_xattr_get(fid, name, value, size);
if (size > 0) {
acl = posix_acl_from_xattr(value, size);
if (IS_ERR(acl))
goto err_out;
}
} else if (size == -ENODATA || size == 0 ||
size == -ENOSYS || size == -EOPNOTSUPP) {
acl = NULL;
} else
acl = ERR_PTR(-EIO);
err_out:
kfree(value);
return acl;
}
int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
{
int retval = 0;
struct posix_acl *pacl, *dacl;
/* get the default/access acl values and cache them */
dacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_DEFAULT);
pacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_ACCESS);
if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
posix_acl_release(dacl);
posix_acl_release(pacl);
} else
retval = -EIO;
return retval;
}
static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
{
struct posix_acl *acl;
/*
* 9p Always cache the acl value when
* instantiating the inode (v9fs_inode_from_fid)
*/
acl = get_cached_acl(inode, type);
BUG_ON(acl == ACL_NOT_CACHED);
return acl;
}
int v9fs_check_acl(struct inode *inode, int mask)
{
struct posix_acl *acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl) {
int error = posix_acl_permission(inode, acl, mask);
posix_acl_release(acl);
return error;
}
return -EAGAIN;
}
static int v9fs_xattr_get_acl(struct dentry *dentry, const char *name,
void *buffer, size_t size, int type)
{
struct posix_acl *acl;
int error;
if (strcmp(name, "") != 0)
return -EINVAL;
acl = v9fs_get_cached_acl(dentry->d_inode, type);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl == NULL)
return -ENODATA;
error = posix_acl_to_xattr(acl, buffer, size);
posix_acl_release(acl);
return error;
}
static int v9fs_xattr_set_acl(struct dentry *dentry, const char *name,
const void *value, size_t size,
int flags, int type)
{
int retval;
struct posix_acl *acl;
struct inode *inode = dentry->d_inode;
if (strcmp(name, "") != 0)
return -EINVAL;
if (S_ISLNK(inode->i_mode))
return -EOPNOTSUPP;
if (!is_owner_or_cap(inode))
return -EPERM;
if (value) {
/* update the cached acl value */
acl = posix_acl_from_xattr(value, size);
if (IS_ERR(acl))
return PTR_ERR(acl);
else if (acl) {
retval = posix_acl_valid(acl);
if (retval)
goto err_out;
}
} else
acl = NULL;
switch (type) {
case ACL_TYPE_ACCESS:
name = POSIX_ACL_XATTR_ACCESS;
if (acl) {
mode_t mode = inode->i_mode;
retval = posix_acl_equiv_mode(acl, &mode);
if (retval < 0)
goto err_out;
else {
struct iattr iattr;
if (retval == 0) {
/*
* ACL can be represented
* by the mode bits. So don't
* update ACL.
*/
acl = NULL;
value = NULL;
size = 0;
}
/* Updte the mode bits */
iattr.ia_mode = ((mode & S_IALLUGO) |
(inode->i_mode & ~S_IALLUGO));
iattr.ia_valid = ATTR_MODE;
/* FIXME should we update ctime ?
* What is the following setxattr update the
* mode ?
*/
v9fs_vfs_setattr_dotl(dentry, &iattr);
}
}
break;
case ACL_TYPE_DEFAULT:
name = POSIX_ACL_XATTR_DEFAULT;
if (!S_ISDIR(inode->i_mode)) {
retval = -EINVAL;
goto err_out;
}
break;
default:
BUG();
}
retval = v9fs_xattr_set(dentry, name, value, size, flags);
if (!retval)
set_cached_acl(inode, type, acl);
err_out:
posix_acl_release(acl);
return retval;
}
const struct xattr_handler v9fs_xattr_acl_access_handler = {
.prefix = POSIX_ACL_XATTR_ACCESS,
.flags = ACL_TYPE_ACCESS,
.get = v9fs_xattr_get_acl,
.set = v9fs_xattr_set_acl,
};
const struct xattr_handler v9fs_xattr_acl_default_handler = {
.prefix = POSIX_ACL_XATTR_DEFAULT,
.flags = ACL_TYPE_DEFAULT,
.get = v9fs_xattr_get_acl,
.set = v9fs_xattr_set_acl,
};
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