[PATCH] Keys: Export user-defined keyring operations

Export user-defined key operations so that those who wish to define their
own key type based on the user-defined key operations may do so (as has
been requested).

The header file created has been placed into include/keys/user-type.h, thus
creating a directory where other key types may also be placed.  Any
objections to doing this?

Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-Off-By: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 47 insertions, 0 deletions

diff --git a/include/keys/user-type.h b/include/keys/user-type.h
new file mode 100644
index 000000000000..26f6ec38577a
--- /dev/null
+++ b/include/keys/user-type.h
@@ -0,0 +1,47 @@
+/* user-type.h: User-defined key type
+ *
+ * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _KEYS_USER_TYPE_H
+#define _KEYS_USER_TYPE_H
+
+#include <linux/key.h>
+#include <linux/rcupdate.h>
+
+/*****************************************************************************/
+/*
+ * the payload for a key of type "user"
+ * - once filled in and attached to a key:
+ *   - the payload struct is invariant may not be changed, only replaced
+ *   - the payload must be read with RCU procedures or with the key semaphore
+ *     held
+ *   - the payload may only be replaced with the key semaphore write-locked
+ * - the key's data length is the size of the actual data, not including the
+ *   payload wrapper
+ */
+struct user_key_payload {
+        struct rcu_head rcu;            /* RCU destructor */
+        unsigned short  datalen;        /* length of this data */
+        char            data[0];        /* actual data */
+};
+
+extern struct key_type key_type_user;
+
+extern int user_instantiate(struct key *key, const void *data, size_t datalen);
+extern int user_duplicate(struct key *key, const struct key *source);
+extern int user_update(struct key *key, const void *data, size_t datalen);
+extern int user_match(const struct key *key, const void *criterion);
+extern void user_destroy(struct key *key);
+extern void user_describe(const struct key *user, struct seq_file *m);
+extern long user_read(const struct key *key,
+                      char __user *buffer, size_t buflen);
+
+
+#endif /* _KEYS_USER_TYPE_H */