include/keys/user-type.h

   1 /* user-type.h: User-defined key type
   2  *
   3  * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #ifndef _KEYS_USER_TYPE_H
  13 #define _KEYS_USER_TYPE_H
  14
  15 #include <linux/key.h>
  16 #include <linux/rcupdate.h>
  17
  18 /*****************************************************************************/
  19 /*
  20  * the payload for a key of type "user"
  21  * - once filled in and attached to a key:
  22  *   - the payload struct is invariant may not be changed, only replaced
  23  *   - the payload must be read with RCU procedures or with the key semaphore
  24  *     held
  25  *   - the payload may only be replaced with the key semaphore write-locked
  26  * - the key's data length is the size of the actual data, not including the
  27  *   payload wrapper
  28  */
  29 struct user_key_payload {
  30         struct rcu_head rcu;            /* RCU destructor */
  31         unsigned short  datalen;        /* length of this data */
  32         char            data[0];        /* actual data */
  33 };
  34
  35 extern struct key_type key_type_user;
  36
  37 extern int user_instantiate(struct key *key, const void *data, size_t datalen);
  38 extern int user_update(struct key *key, const void *data, size_t datalen);
  39 extern int user_match(const struct key *key, const void *criterion);
  40 extern void user_destroy(struct key *key);
  41 extern void user_describe(const struct key *user, struct seq_file *m);
  42 extern long user_read(const struct key *key,
  43                       char __user *buffer, size_t buflen);
  44
  45
  46 #endif /* _KEYS_USER_TYPE_H */