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/*
* mm/shmem_acl.c
*
* (C) 2005 Andreas Gruenbacher <agruen@suse.de>
*
* This file is released under the GPL.
*/
#include <linux/fs.h>
#include <linux/shmem_fs.h>
#include <linux/xattr.h>
#include <linux/generic_acl.h>
/**
* shmem_get_acl - generic_acl_operations->getacl() operation
*/
static struct posix_acl *
shmem_get_acl(struct inode *inode, int type)
{
struct posix_acl *acl = NULL;
spin_lock(&inode->i_lock);
switch(type) {
case ACL_TYPE_ACCESS:
acl = posix_acl_dup(SHMEM_I(inode)->i_acl);
break;
case ACL_TYPE_DEFAULT:
acl = posix_acl_dup(SHMEM_I(inode)->i_default_acl);
break;
}
spin_unlock(&inode->i_lock);
return acl;
}
/**
* shmem_set_acl - generic_acl_operations->setacl() operation
*/
static void
shmem_set_acl(struct inode *inode, int type, struct posix_acl *acl)
{
struct posix_acl *free = NULL;
spin_lock(&inode->i_lock);
switch(type) {
case ACL_TYPE_ACCESS:
free = SHMEM_I(inode)->i_acl;
SHMEM_I(inode)->i_acl = posix_acl_dup(acl);
break;
case ACL_TYPE_DEFAULT:
free = SHMEM_I(inode)->i_default_acl;
SHMEM_I(inode)->i_default_acl = posix_acl_dup(acl);
break;
}
spin_unlock(&inode->i_lock);
posix_acl_release(free);
}
struct generic_acl_operations shmem_acl_ops = {
.getacl = shmem_get_acl,
.setacl = shmem_set_acl,
};
/**
* shmem_list_acl_access, shmem_get_acl_access, shmem_set_acl_access,
* shmem_xattr_acl_access_handler - plumbing code to implement the
* system.posix_acl_access xattr using the generic acl functions.
*/
static size_t
shmem_list_acl_access(struct inode *inode, char *list, size_t list_size,
const char *name, size_t name_len)
{
return generic_acl_list(inode, &shmem_acl_ops, ACL_TYPE_ACCESS,
list, list_size);
}
static int
shmem_get_acl_access(struct inode *inode, const char *name, void *buffer,
size_t size)
{
if (strcmp(name, "") != 0)
return -EINVAL;
return generic_acl_get(inode, &shmem_acl_ops, ACL_TYPE_ACCESS, buffer,
size);
}
static int
shmem_set_acl_access(struct inode *inode, const char *name, const void *value,
size_t size, int flags)
{
if (strcmp(name, "") != 0)
return -EINVAL;
return generic_acl_set(inode, &shmem_acl_ops, ACL_TYPE_ACCESS, value,
size);
}
struct xattr_handler shmem_xattr_acl_access_handler = {
.prefix = POSIX_ACL_XATTR_ACCESS,
.list = shmem_list_acl_access,
.get = shmem_get_acl_access,
.set = shmem_set_acl_access,
};
/**
* shmem_list_acl_default, shmem_get_acl_default, shmem_set_acl_default,
* shmem_xattr_acl_default_handler - plumbing code to implement the
* system.posix_acl_default xattr using the generic acl functions.
*/
static size_t
shmem_list_acl_default(struct inode *inode, char *list, size_t list_size,
const char *name, size_t name_len)
{
return generic_acl_list(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT,
list, list_size);
}
static int
shmem_get_acl_default(struct inode *inode, const char *name, void *buffer,
size_t size)
{
if (strcmp(name, "") != 0)
return -EINVAL;
return generic_acl_get(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT, buffer,
size);
}
static int
shmem_set_acl_default(struct inode *inode, const char *name, const void *value,
size_t size, int flags)
{
if (strcmp(name, "") != 0)
return -EINVAL;
return generic_acl_set(inode, &shmem_acl_ops, ACL_TYPE_DEFAULT, value,
size);
}
struct xattr_handler shmem_xattr_acl_default_handler = {
.prefix = POSIX_ACL_XATTR_DEFAULT,
.list = shmem_list_acl_default,
.get = shmem_get_acl_default,
.set = shmem_set_acl_default,
};
/**
* shmem_acl_init - Inizialize the acl(s) of a new inode
*/
int
shmem_acl_init(struct inode *inode, struct inode *dir)
{
return generic_acl_init(inode, dir, &shmem_acl_ops);
}
/**
* shmem_acl_destroy_inode - destroy acls hanging off the in-memory inode
*
* This is done before destroying the actual inode.
*/
void
shmem_acl_destroy_inode(struct inode *inode)
{
if (SHMEM_I(inode)->i_acl)
posix_acl_release(SHMEM_I(inode)->i_acl);
SHMEM_I(inode)->i_acl = NULL;
if (SHMEM_I(inode)->i_default_acl)
posix_acl_release(SHMEM_I(inode)->i_default_acl);
SHMEM_I(inode)->i_default_acl = NULL;
}
/**
* shmem_check_acl - check_acl() callback for generic_permission()
*/
static int
shmem_check_acl(struct inode *inode, int mask)
{
struct posix_acl *acl = shmem_get_acl(inode, ACL_TYPE_ACCESS);
if (acl) {
int error = posix_acl_permission(inode, acl, mask);
posix_acl_release(acl);
return error;
}
return -EAGAIN;
}
/**
* shmem_permission - permission() inode operation
*/
int
shmem_permission(struct inode *inode, int mask, struct nameidata *nd)
{
return generic_permission(inode, mask, shmem_check_acl);
}
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