linux/fs/generic_acl.c
Stephen Hemminger bb4354538e fs: xattr_handler table should be const
The entries in xattr handler table should be immutable (ie const)
like other operation tables.

Later patches convert common filesystems. Uncoverted filesystems
will still work, but will generate a compiler warning.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-21 18:31:18 -04:00

219 lines
4.5 KiB
C

/*
* (C) 2005 Andreas Gruenbacher <agruen@suse.de>
*
* This file is released under the GPL.
*
* Generic ACL support for in-memory filesystems.
*/
#include <linux/sched.h>
#include <linux/gfp.h>
#include <linux/fs.h>
#include <linux/generic_acl.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
static size_t
generic_acl_list(struct dentry *dentry, char *list, size_t list_size,
const char *name, size_t name_len, int type)
{
struct posix_acl *acl;
const char *xname;
size_t size;
acl = get_cached_acl(dentry->d_inode, type);
if (!acl)
return 0;
posix_acl_release(acl);
switch (type) {
case ACL_TYPE_ACCESS:
xname = POSIX_ACL_XATTR_ACCESS;
break;
case ACL_TYPE_DEFAULT:
xname = POSIX_ACL_XATTR_DEFAULT;
break;
default:
return 0;
}
size = strlen(xname) + 1;
if (list && size <= list_size)
memcpy(list, xname, size);
return size;
}
static int
generic_acl_get(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 = get_cached_acl(dentry->d_inode, type);
if (!acl)
return -ENODATA;
error = posix_acl_to_xattr(acl, buffer, size);
posix_acl_release(acl);
return error;
}
static int
generic_acl_set(struct dentry *dentry, const char *name, const void *value,
size_t size, int flags, int type)
{
struct inode *inode = dentry->d_inode;
struct posix_acl *acl = NULL;
int error;
if (strcmp(name, "") != 0)
return -EINVAL;
if (S_ISLNK(inode->i_mode))
return -EOPNOTSUPP;
if (!is_owner_or_cap(inode))
return -EPERM;
if (value) {
acl = posix_acl_from_xattr(value, size);
if (IS_ERR(acl))
return PTR_ERR(acl);
}
if (acl) {
mode_t mode;
error = posix_acl_valid(acl);
if (error)
goto failed;
switch (type) {
case ACL_TYPE_ACCESS:
mode = inode->i_mode;
error = posix_acl_equiv_mode(acl, &mode);
if (error < 0)
goto failed;
inode->i_mode = mode;
if (error == 0) {
posix_acl_release(acl);
acl = NULL;
}
break;
case ACL_TYPE_DEFAULT:
if (!S_ISDIR(inode->i_mode)) {
error = -EINVAL;
goto failed;
}
break;
}
}
set_cached_acl(inode, type, acl);
error = 0;
failed:
posix_acl_release(acl);
return error;
}
/**
* generic_acl_init - Take care of acl inheritance at @inode create time
*
* Files created inside a directory with a default ACL inherit the
* directory's default ACL.
*/
int
generic_acl_init(struct inode *inode, struct inode *dir)
{
struct posix_acl *acl = NULL;
mode_t mode = inode->i_mode;
int error;
inode->i_mode = mode & ~current_umask();
if (!S_ISLNK(inode->i_mode))
acl = get_cached_acl(dir, ACL_TYPE_DEFAULT);
if (acl) {
struct posix_acl *clone;
if (S_ISDIR(inode->i_mode)) {
clone = posix_acl_clone(acl, GFP_KERNEL);
error = -ENOMEM;
if (!clone)
goto cleanup;
set_cached_acl(inode, ACL_TYPE_DEFAULT, clone);
posix_acl_release(clone);
}
clone = posix_acl_clone(acl, GFP_KERNEL);
error = -ENOMEM;
if (!clone)
goto cleanup;
error = posix_acl_create_masq(clone, &mode);
if (error >= 0) {
inode->i_mode = mode;
if (error > 0)
set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
}
posix_acl_release(clone);
}
error = 0;
cleanup:
posix_acl_release(acl);
return error;
}
/**
* generic_acl_chmod - change the access acl of @inode upon chmod()
*
* A chmod also changes the permissions of the owner, group/mask, and
* other ACL entries.
*/
int
generic_acl_chmod(struct inode *inode)
{
struct posix_acl *acl, *clone;
int error = 0;
if (S_ISLNK(inode->i_mode))
return -EOPNOTSUPP;
acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
if (acl) {
clone = posix_acl_clone(acl, GFP_KERNEL);
posix_acl_release(acl);
if (!clone)
return -ENOMEM;
error = posix_acl_chmod_masq(clone, inode->i_mode);
if (!error)
set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
posix_acl_release(clone);
}
return error;
}
int
generic_check_acl(struct inode *inode, int mask)
{
struct posix_acl *acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
if (acl) {
int error = posix_acl_permission(inode, acl, mask);
posix_acl_release(acl);
return error;
}
return -EAGAIN;
}
const struct xattr_handler generic_acl_access_handler = {
.prefix = POSIX_ACL_XATTR_ACCESS,
.flags = ACL_TYPE_ACCESS,
.list = generic_acl_list,
.get = generic_acl_get,
.set = generic_acl_set,
};
const struct xattr_handler generic_acl_default_handler = {
.prefix = POSIX_ACL_XATTR_DEFAULT,
.flags = ACL_TYPE_DEFAULT,
.list = generic_acl_list,
.get = generic_acl_get,
.set = generic_acl_set,
};