1 /* user_defined.c: user defined key type
3 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/sched.h>
15 #include <linux/slab.h>
16 #include <linux/seq_file.h>
17 #include <linux/err.h>
18 #include <asm/uaccess.h>
21 static int user_instantiate(struct key *key, const void *data, size_t datalen);
22 static int user_duplicate(struct key *key, const struct key *source);
23 static int user_update(struct key *key, const void *data, size_t datalen);
24 static int user_match(const struct key *key, const void *criterion);
25 static void user_destroy(struct key *key);
26 static void user_describe(const struct key *user, struct seq_file *m);
27 static long user_read(const struct key *key,
28 char __user *buffer, size_t buflen);
31 * user defined keys take an arbitrary string as the description and an
32 * arbitrary blob of data as the payload
34 struct key_type key_type_user = {
36 .instantiate = user_instantiate,
37 .duplicate = user_duplicate,
38 .update = user_update,
40 .destroy = user_destroy,
41 .describe = user_describe,
45 /*****************************************************************************/
47 * instantiate a user defined key
49 static int user_instantiate(struct key *key, const void *data, size_t datalen)
54 if (datalen <= 0 || datalen > 32767 || !data)
57 ret = key_payload_reserve(key, datalen);
63 key->payload.data = kmalloc(datalen, GFP_KERNEL);
64 if (!key->payload.data)
67 memcpy(key->payload.data, data, datalen);
73 } /* end user_instantiate() */
75 /*****************************************************************************/
77 * duplicate a user defined key
79 static int user_duplicate(struct key *key, const struct key *source)
83 /* just copy the payload */
85 key->payload.data = kmalloc(source->datalen, GFP_KERNEL);
87 if (key->payload.data) {
88 key->datalen = source->datalen;
89 memcpy(key->payload.data, source->payload.data, source->datalen);
95 } /* end user_duplicate() */
97 /*****************************************************************************/
99 * update a user defined key
101 static int user_update(struct key *key, const void *data, size_t datalen)
107 if (datalen <= 0 || datalen > 32767 || !data)
112 new = kmalloc(datalen, GFP_KERNEL);
116 memcpy(new, data, datalen);
118 /* check the quota and attach the new data */
120 write_lock(&key->lock);
122 ret = key_payload_reserve(key, datalen);
125 /* attach the new data, displacing the old */
126 zap = key->payload.data;
127 key->payload.data = new;
131 write_unlock(&key->lock);
137 } /* end user_update() */
139 /*****************************************************************************/
141 * match users on their name
143 static int user_match(const struct key *key, const void *description)
145 return strcmp(key->description, description) == 0;
147 } /* end user_match() */
149 /*****************************************************************************/
151 * dispose of the data dangling from the corpse of a user
153 static void user_destroy(struct key *key)
155 kfree(key->payload.data);
157 } /* end user_destroy() */
159 /*****************************************************************************/
163 static void user_describe(const struct key *key, struct seq_file *m)
165 seq_puts(m, key->description);
167 seq_printf(m, ": %u", key->datalen);
169 } /* end user_describe() */
171 /*****************************************************************************/
175 static long user_read(const struct key *key,
176 char __user *buffer, size_t buflen)
178 long ret = key->datalen;
180 /* we can return the data as is */
181 if (buffer && buflen > 0) {
182 if (buflen > key->datalen)
183 buflen = key->datalen;
185 if (copy_to_user(buffer, key->payload.data, buflen) != 0)
191 } /* end user_read() */