text: /*
    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/bug.h>
  #include <linux/slab.h>
  #include <linux/rcupdate.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;
  	union {
  		kuid_t		e_uid;
  		kgid_t		e_gid;
  	};
  };
  
  struct posix_acl {
  	union {
  		atomic_t		a_refcount;
  		struct rcu_head		a_rcu;
  	};
  	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_rcu(acl, a_rcu);
  }
  
  
  /* posix_acl.c */
  
  extern void posix_acl_init(struct posix_acl *, int);
  extern struct posix_acl *posix_acl_alloc(int, 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(umode_t, gfp_t);
  extern int posix_acl_equiv_mode(const struct posix_acl *, umode_t *);
  extern int __posix_acl_create(struct posix_acl **, gfp_t, umode_t *);
  extern int __posix_acl_chmod(struct posix_acl **, gfp_t, umode_t);
  
  extern struct posix_acl *get_posix_acl(struct inode *, int);
  extern int set_posix_acl(struct inode *, int, struct posix_acl *);
  
  #ifdef CONFIG_FS_POSIX_ACL
  extern int posix_acl_chmod(struct inode *, umode_t);
  extern int posix_acl_create(struct inode *, umode_t *, struct posix_acl **,
  		struct posix_acl **);
  extern int posix_acl_update_mode(struct inode *, umode_t *, struct posix_acl **);
  
  extern int simple_set_acl(struct inode *, struct posix_acl *, int);
  extern int simple_acl_create(struct inode *, struct inode *);
  
  struct posix_acl **acl_by_type(struct inode *inode, int type);
  struct posix_acl *get_cached_acl(struct inode *inode, int type);
  struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type);
  void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl);
  void forget_cached_acl(struct inode *inode, int type);
  void forget_all_cached_acls(struct inode *inode);
  
  static inline void cache_no_acl(struct inode *inode)
  {
  	inode->i_acl = NULL;
  	inode->i_default_acl = NULL;
  }
  #else
  static inline int posix_acl_chmod(struct inode *inode, umode_t mode)
  {
  	return 0;
  }
  
  #define simple_set_acl		NULL
  
  static inline int simple_acl_create(struct inode *dir, struct inode *inode)
  {
  	return 0;
  }
  static inline void cache_no_acl(struct inode *inode)
  {
  }
  
  static inline int posix_acl_create(struct inode *inode, umode_t *mode,
  		struct posix_acl **default_acl, struct posix_acl **acl)
  {
  	*default_acl = *acl = NULL;
  	return 0;
  }
  
  static inline void forget_all_cached_acls(struct inode *inode)
  {
  }
  #endif /* CONFIG_FS_POSIX_ACL */
  
  struct posix_acl *get_acl(struct inode *inode, int type);
  
  #endif  /* __LINUX_POSIX_ACL_H */
  