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/*
File: linux/posix_acl.h
(C) 2002 Andreas Gruenbacher, <a.gruenbacher@computer.org>
*/
#ifndef __LINUX_POSIX_ACL_H
#define __LINUX_POSIX_ACL_H
#include <linux/slab.h>
#define ACL_UNDEFINED_ID (-1)
/* a_type field in acl_user_posix_entry_t */
#define ACL_TYPE_ACCESS (0x8000)
#define ACL_TYPE_DEFAULT (0x4000)
/* e_tag entry in struct posix_acl_entry */
#define ACL_USER_OBJ (0x01)
#define ACL_USER (0x02)
#define ACL_GROUP_OBJ (0x04)
#define ACL_GROUP (0x08)
#define ACL_MASK (0x10)
#define ACL_OTHER (0x20)
/* permissions in the e_perm field */
#define ACL_READ (0x04)
#define ACL_WRITE (0x02)
#define ACL_EXECUTE (0x01)
//#define ACL_ADD (0x08)
//#define ACL_DELETE (0x10)
struct posix_acl_entry {
short e_tag;
unsigned short e_perm;
unsigned int e_id;
};
struct posix_acl {
atomic_t a_refcount;
unsigned int a_count;
struct posix_acl_entry a_entries[0];
};
#define FOREACH_ACL_ENTRY(pa, acl, pe) \
for(pa=(acl)->a_entries, pe=pa+(acl)->a_count; pa<pe; pa++)
/*
* Duplicate an ACL handle.
*/
static inline struct posix_acl *
posix_acl_dup(struct posix_acl *acl)
{
if (acl)
atomic_inc(&acl->a_refcount);
return acl;
}
/*
* Free an ACL handle.
*/
static inline void
posix_acl_release(struct posix_acl *acl)
{
if (acl && atomic_dec_and_test(&acl->a_refcount))
kfree(acl);
}
/* posix_acl.c */
extern struct posix_acl *posix_acl_alloc(int, gfp_t);
extern struct posix_acl *posix_acl_clone(const struct posix_acl *, gfp_t);
extern int posix_acl_valid(const struct posix_acl *);
extern int posix_acl_permission(struct inode *, const struct posix_acl *, int);
extern struct posix_acl *posix_acl_from_mode(mode_t, gfp_t);
extern int posix_acl_equiv_mode(const struct posix_acl *, mode_t *);
extern int posix_acl_create_masq(struct posix_acl *, mode_t *);
extern int posix_acl_chmod_masq(struct posix_acl *, mode_t);
extern struct posix_acl *get_posix_acl(struct inode *, int);
extern int set_posix_acl(struct inode *, int, struct posix_acl *);
static inline struct posix_acl *get_cached_acl(struct inode *inode, int type)
{
struct posix_acl **p, *acl;
switch (type) {
case ACL_TYPE_ACCESS:
p = &inode->i_acl;
break;
case ACL_TYPE_DEFAULT:
p = &inode->i_default_acl;
break;
default:
return ERR_PTR(-EINVAL);
}
acl = ACCESS_ONCE(*p);
if (acl) {
spin_lock(&inode->i_lock);
acl = *p;
if (acl != ACL_NOT_CACHED)
acl = posix_acl_dup(acl);
spin_unlock(&inode->i_lock);
}
return acl;
}
static inline void set_cached_acl(struct inode *inode,
int type,
struct posix_acl *acl)
{
struct posix_acl *old = NULL;
spin_lock(&inode->i_lock);
switch (type) {
case ACL_TYPE_ACCESS:
old = inode->i_acl;
inode->i_acl = posix_acl_dup(acl);
break;
case ACL_TYPE_DEFAULT:
old = inode->i_default_acl;
inode->i_default_acl = posix_acl_dup(acl);
break;
}
spin_unlock(&inode->i_lock);
if (old != ACL_NOT_CACHED)
posix_acl_release(old);
}
static inline void forget_cached_acl(struct inode *inode, int type)
{
struct posix_acl *old = NULL;
spin_lock(&inode->i_lock);
switch (type) {
case ACL_TYPE_ACCESS:
old = inode->i_acl;
inode->i_acl = ACL_NOT_CACHED;
break;
case ACL_TYPE_DEFAULT:
old = inode->i_default_acl;
inode->i_default_acl = ACL_NOT_CACHED;
break;
}
spin_unlock(&inode->i_lock);
if (old != ACL_NOT_CACHED)
posix_acl_release(old);
}
#endif /* __LINUX_POSIX_ACL_H */
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