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alistair23-linux/fs/gfs2/acl.c
Christoph Hellwig 431547b3c4 sanitize xattr handler prototypes 
Add a flags argument to struct xattr_handler and pass it to all xattr
handler methods.  This allows using the same methods for multiple
handlers, e.g. for the ACL methods which perform exactly the same action
for the access and default ACLs, just using a different underlying
attribute.  With a little more groundwork it'll also allow sharing the
methods for the regular user/trusted/secure handlers in extN, ocfs2 and
jffs2 like it's already done for xfs in this patch.

Also change the inode argument to the handlers to a dentry to allow
using the handlers mechnism for filesystems that require it later,
e.g. cifs.

[with GFS2 bits updated by Steven Whitehouse <swhiteho@redhat.com>]

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-16 12:16:49 -05:00

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/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License version 2.
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/xattr.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#include <linux/gfs2_ondisk.h>
#include "gfs2.h"
#include "incore.h"
#include "acl.h"
#include "xattr.h"
#include "glock.h"
#include "inode.h"
#include "meta_io.h"
#include "trans.h"
#include "util.h"
static const char *gfs2_acl_name(int type)
{
switch (type) {
case ACL_TYPE_ACCESS:
return GFS2_POSIX_ACL_ACCESS;
case ACL_TYPE_DEFAULT:
return GFS2_POSIX_ACL_DEFAULT;
}
return NULL;
}
static struct posix_acl *gfs2_acl_get(struct gfs2_inode *ip, int type)
{
struct posix_acl *acl;
const char *name;
char *data;
int len;
if (!ip->i_eattr)
return NULL;
acl = get_cached_acl(&ip->i_inode, type);
if (acl != ACL_NOT_CACHED)
return acl;
name = gfs2_acl_name(type);
if (name == NULL)
return ERR_PTR(-EINVAL);
len = gfs2_xattr_acl_get(ip, name, &data);
if (len < 0)
return ERR_PTR(len);
if (len == 0)
return NULL;
acl = posix_acl_from_xattr(data, len);
kfree(data);
return acl;
}
/**
* gfs2_check_acl - Check an ACL to see if we're allowed to do something
* @inode: the file we want to do something to
* @mask: what we want to do
*
* Returns: errno
*/
int gfs2_check_acl(struct inode *inode, int mask)
{
struct posix_acl *acl;
int error;
acl = gfs2_acl_get(GFS2_I(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;
}
return -EAGAIN;
}
static int gfs2_set_mode(struct inode *inode, mode_t mode)
{
int error = 0;
if (mode != inode->i_mode) {
struct iattr iattr;
iattr.ia_valid = ATTR_MODE;
iattr.ia_mode = mode;
error = gfs2_setattr_simple(GFS2_I(inode), &iattr);
}
return error;
}
static int gfs2_acl_set(struct inode *inode, int type, struct posix_acl *acl)
{
int error;
int len;
char *data;
const char *name = gfs2_acl_name(type);
BUG_ON(name == NULL);
len = posix_acl_to_xattr(acl, NULL, 0);
if (len == 0)
return 0;
data = kmalloc(len, GFP_NOFS);
if (data == NULL)
return -ENOMEM;
error = posix_acl_to_xattr(acl, data, len);
if (error < 0)
goto out;
error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
if (!error)
set_cached_acl(inode, type, acl);
out:
kfree(data);
return error;
}
int gfs2_acl_create(struct gfs2_inode *dip, struct inode *inode)
{
struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
struct posix_acl *acl, *clone;
mode_t mode = inode->i_mode;
int error = 0;
if (!sdp->sd_args.ar_posix_acl)
return 0;
if (S_ISLNK(inode->i_mode))
return 0;
acl = gfs2_acl_get(dip, ACL_TYPE_DEFAULT);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (!acl) {
mode &= ~current_umask();
if (mode != inode->i_mode)
error = gfs2_set_mode(inode, mode);
return error;
}
if (S_ISDIR(inode->i_mode)) {
error = gfs2_acl_set(inode, ACL_TYPE_DEFAULT, acl);
if (error)
goto out;
}
clone = posix_acl_clone(acl, GFP_NOFS);
error = -ENOMEM;
if (!clone)
goto out;
posix_acl_release(acl);
acl = clone;
error = posix_acl_create_masq(acl, &mode);
if (error < 0)
goto out;
if (error == 0)
goto munge;
error = gfs2_acl_set(inode, ACL_TYPE_ACCESS, acl);
if (error)
goto out;
munge:
error = gfs2_set_mode(inode, mode);
out:
posix_acl_release(acl);
return error;
}
int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr)
{
struct posix_acl *acl, *clone;
char *data;
unsigned int len;
int error;
acl = gfs2_acl_get(ip, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (!acl)
return gfs2_setattr_simple(ip, attr);
clone = posix_acl_clone(acl, GFP_NOFS);
error = -ENOMEM;
if (!clone)
goto out;
posix_acl_release(acl);
acl = clone;
error = posix_acl_chmod_masq(acl, attr->ia_mode);
if (!error) {
len = posix_acl_to_xattr(acl, NULL, 0);
data = kmalloc(len, GFP_NOFS);
error = -ENOMEM;
if (data == NULL)
goto out;
posix_acl_to_xattr(acl, data, len);
error = gfs2_xattr_acl_chmod(ip, attr, data);
kfree(data);
set_cached_acl(&ip->i_inode, ACL_TYPE_ACCESS, acl);
}
out:
posix_acl_release(acl);
return error;
}
static int gfs2_acl_type(const char *name)
{
if (strcmp(name, GFS2_POSIX_ACL_ACCESS) == 0)
return ACL_TYPE_ACCESS;
if (strcmp(name, GFS2_POSIX_ACL_DEFAULT) == 0)
return ACL_TYPE_DEFAULT;
return -EINVAL;
}
static int gfs2_xattr_system_get(struct dentry *dentry, const char *name,
void *buffer, size_t size, int xtype)
{
struct inode *inode = dentry->d_inode;
struct posix_acl *acl;
int type;
int error;
type = gfs2_acl_type(name);
if (type < 0)
return type;
acl = gfs2_acl_get(GFS2_I(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 gfs2_xattr_system_set(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags,
int xtype)
{
struct inode *inode = dentry->d_inode;
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct posix_acl *acl = NULL;
int error = 0, type;
if (!sdp->sd_args.ar_posix_acl)
return -EOPNOTSUPP;
type = gfs2_acl_type(name);
if (type < 0)
return type;
if (flags & XATTR_CREATE)
return -EINVAL;
if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
return value ? -EACCES : 0;
if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
return -EPERM;
if (S_ISLNK(inode->i_mode))
return -EOPNOTSUPP;
if (!value)
goto set_acl;
acl = posix_acl_from_xattr(value, size);
if (!acl) {
/*
* acl_set_file(3) may request that we set default ACLs with
* zero length -- defend (gracefully) against that here.
*/
goto out;
}
if (IS_ERR(acl)) {
error = PTR_ERR(acl);
goto out;
}
error = posix_acl_valid(acl);
if (error)
goto out_release;
error = -EINVAL;
if (acl->a_count > GFS2_ACL_MAX_ENTRIES)
goto out_release;
if (type == ACL_TYPE_ACCESS) {
mode_t mode = inode->i_mode;
error = posix_acl_equiv_mode(acl, &mode);
if (error <= 0) {
posix_acl_release(acl);
acl = NULL;
if (error < 0)
return error;
}
error = gfs2_set_mode(inode, mode);
if (error)
goto out_release;
}
set_acl:
error = __gfs2_xattr_set(inode, name, value, size, 0, GFS2_EATYPE_SYS);
if (!error) {
if (acl)
set_cached_acl(inode, type, acl);
else
forget_cached_acl(inode, type);
}
out_release:
posix_acl_release(acl);
out:
return error;
}
struct xattr_handler gfs2_xattr_system_handler = {
.prefix = XATTR_SYSTEM_PREFIX,
.flags = GFS2_EATYPE_SYS,
.get = gfs2_xattr_system_get,
.set = gfs2_xattr_system_set,
};
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