blob: efd95a0ed1ea036459667628babd085f7803cd4f [file] [log] [blame]
Michael Halcrow8bf2deb2008-04-29 00:59:50 -07001/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 2008 International Business Machines Corp.
5 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License version
9 * 2 as published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
19 * 02111-1307, USA.
20 */
21
22#include <linux/fs.h>
23#include <linux/hash.h>
24#include <linux/random.h>
25#include <linux/miscdevice.h>
26#include <linux/poll.h>
27#include <linux/wait.h>
28#include <linux/module.h>
29#include "ecryptfs_kernel.h"
30
31static atomic_t ecryptfs_num_miscdev_opens;
32
33/**
34 * ecryptfs_miscdev_poll
35 * @file: dev file (ignored)
36 * @pt: dev poll table (ignored)
37 *
38 * Returns the poll mask
39 */
40static unsigned int
41ecryptfs_miscdev_poll(struct file *file, poll_table *pt)
42{
43 struct ecryptfs_daemon *daemon;
44 unsigned int mask = 0;
David Howells4eea0352008-11-14 10:38:49 +110045 uid_t euid = current_euid();
Michael Halcrow8bf2deb2008-04-29 00:59:50 -070046 int rc;
47
48 mutex_lock(&ecryptfs_daemon_hash_mux);
49 /* TODO: Just use file->private_data? */
Serge Hallyn18b6e042008-10-15 16:38:45 -050050 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
Michael Halcrow8bf2deb2008-04-29 00:59:50 -070051 BUG_ON(rc || !daemon);
52 mutex_lock(&daemon->mux);
53 mutex_unlock(&ecryptfs_daemon_hash_mux);
54 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
55 printk(KERN_WARNING "%s: Attempt to poll on zombified "
56 "daemon\n", __func__);
57 goto out_unlock_daemon;
58 }
59 if (daemon->flags & ECRYPTFS_DAEMON_IN_READ)
60 goto out_unlock_daemon;
61 if (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)
62 goto out_unlock_daemon;
63 daemon->flags |= ECRYPTFS_DAEMON_IN_POLL;
64 mutex_unlock(&daemon->mux);
65 poll_wait(file, &daemon->wait, pt);
66 mutex_lock(&daemon->mux);
67 if (!list_empty(&daemon->msg_ctx_out_queue))
68 mask |= POLLIN | POLLRDNORM;
69out_unlock_daemon:
70 daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL;
71 mutex_unlock(&daemon->mux);
72 return mask;
73}
74
75/**
76 * ecryptfs_miscdev_open
77 * @inode: inode of miscdev handle (ignored)
78 * @file: file for miscdev handle (ignored)
79 *
80 * Returns zero on success; non-zero otherwise
81 */
82static int
83ecryptfs_miscdev_open(struct inode *inode, struct file *file)
84{
85 struct ecryptfs_daemon *daemon = NULL;
David Howells4eea0352008-11-14 10:38:49 +110086 uid_t euid = current_euid();
Michael Halcrow8bf2deb2008-04-29 00:59:50 -070087 int rc;
88
89 mutex_lock(&ecryptfs_daemon_hash_mux);
90 rc = try_module_get(THIS_MODULE);
91 if (rc == 0) {
92 rc = -EIO;
93 printk(KERN_ERR "%s: Error attempting to increment module use "
94 "count; rc = [%d]\n", __func__, rc);
95 goto out_unlock_daemon_list;
96 }
Serge Hallyn18b6e042008-10-15 16:38:45 -050097 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
Michael Halcrow8bf2deb2008-04-29 00:59:50 -070098 if (rc || !daemon) {
Serge Hallyn18b6e042008-10-15 16:38:45 -050099 rc = ecryptfs_spawn_daemon(&daemon, euid, current_user_ns(),
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700100 task_pid(current));
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700101 if (rc) {
102 printk(KERN_ERR "%s: Error attempting to spawn daemon; "
103 "rc = [%d]\n", __func__, rc);
104 goto out_module_put_unlock_daemon_list;
105 }
106 }
107 mutex_lock(&daemon->mux);
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700108 if (daemon->pid != task_pid(current)) {
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700109 rc = -EINVAL;
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700110 printk(KERN_ERR "%s: pid [0x%p] has registered with euid [%d], "
111 "but pid [0x%p] has attempted to open the handle "
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700112 "instead\n", __func__, daemon->pid, daemon->euid,
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700113 task_pid(current));
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700114 goto out_unlock_daemon;
115 }
116 if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) {
117 rc = -EBUSY;
118 printk(KERN_ERR "%s: Miscellaneous device handle may only be "
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700119 "opened once per daemon; pid [0x%p] already has this "
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700120 "handle open\n", __func__, daemon->pid);
121 goto out_unlock_daemon;
122 }
123 daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN;
124 atomic_inc(&ecryptfs_num_miscdev_opens);
125out_unlock_daemon:
126 mutex_unlock(&daemon->mux);
127out_module_put_unlock_daemon_list:
128 if (rc)
129 module_put(THIS_MODULE);
130out_unlock_daemon_list:
131 mutex_unlock(&ecryptfs_daemon_hash_mux);
132 return rc;
133}
134
135/**
136 * ecryptfs_miscdev_release
137 * @inode: inode of fs/ecryptfs/euid handle (ignored)
138 * @file: file for fs/ecryptfs/euid handle (ignored)
139 *
140 * This keeps the daemon registered until the daemon sends another
141 * ioctl to fs/ecryptfs/ctl or until the kernel module unregisters.
142 *
143 * Returns zero on success; non-zero otherwise
144 */
145static int
146ecryptfs_miscdev_release(struct inode *inode, struct file *file)
147{
148 struct ecryptfs_daemon *daemon = NULL;
David Howells4eea0352008-11-14 10:38:49 +1100149 uid_t euid = current_euid();
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700150 int rc;
151
152 mutex_lock(&ecryptfs_daemon_hash_mux);
Serge Hallyn18b6e042008-10-15 16:38:45 -0500153 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700154 BUG_ON(rc || !daemon);
155 mutex_lock(&daemon->mux);
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700156 BUG_ON(daemon->pid != task_pid(current));
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700157 BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN));
158 daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN;
159 atomic_dec(&ecryptfs_num_miscdev_opens);
160 mutex_unlock(&daemon->mux);
161 rc = ecryptfs_exorcise_daemon(daemon);
162 if (rc) {
163 printk(KERN_CRIT "%s: Fatal error whilst attempting to "
164 "shut down daemon; rc = [%d]. Please report this "
165 "bug.\n", __func__, rc);
166 BUG();
167 }
168 module_put(THIS_MODULE);
169 mutex_unlock(&ecryptfs_daemon_hash_mux);
170 return rc;
171}
172
173/**
174 * ecryptfs_send_miscdev
175 * @data: Data to send to daemon; may be NULL
176 * @data_size: Amount of data to send to daemon
177 * @msg_ctx: Message context, which is used to handle the reply. If
178 * this is NULL, then we do not expect a reply.
179 * @msg_type: Type of message
180 * @msg_flags: Flags for message
181 * @daemon: eCryptfs daemon object
182 *
183 * Add msg_ctx to queue and then, if it exists, notify the blocked
184 * miscdevess about the data being available. Must be called with
185 * ecryptfs_daemon_hash_mux held.
186 *
187 * Returns zero on success; non-zero otherwise
188 */
189int ecryptfs_send_miscdev(char *data, size_t data_size,
190 struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
191 u16 msg_flags, struct ecryptfs_daemon *daemon)
192{
193 int rc = 0;
194
195 mutex_lock(&msg_ctx->mux);
196 if (data) {
197 msg_ctx->msg = kmalloc((sizeof(*msg_ctx->msg) + data_size),
198 GFP_KERNEL);
199 if (!msg_ctx->msg) {
200 rc = -ENOMEM;
201 printk(KERN_ERR "%s: Out of memory whilst attempting "
Michael Halcrowf66e8832008-04-29 00:59:51 -0700202 "to kmalloc(%Zd, GFP_KERNEL)\n", __func__,
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700203 (sizeof(*msg_ctx->msg) + data_size));
204 goto out_unlock;
205 }
206 } else
207 msg_ctx->msg = NULL;
208 msg_ctx->msg->index = msg_ctx->index;
209 msg_ctx->msg->data_len = data_size;
210 msg_ctx->type = msg_type;
211 if (data) {
212 memcpy(msg_ctx->msg->data, data, data_size);
213 msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size);
214 } else
215 msg_ctx->msg_size = 0;
216 mutex_lock(&daemon->mux);
217 list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
218 daemon->num_queued_msg_ctx++;
219 wake_up_interruptible(&daemon->wait);
220 mutex_unlock(&daemon->mux);
221out_unlock:
222 mutex_unlock(&msg_ctx->mux);
223 return rc;
224}
225
226/**
227 * ecryptfs_miscdev_read - format and send message from queue
228 * @file: fs/ecryptfs/euid miscdevfs handle (ignored)
229 * @buf: User buffer into which to copy the next message on the daemon queue
230 * @count: Amount of space available in @buf
231 * @ppos: Offset in file (ignored)
232 *
233 * Pulls the most recent message from the daemon queue, formats it for
234 * being sent via a miscdevfs handle, and copies it into @buf
235 *
236 * Returns the number of bytes copied into the user buffer
237 */
Michael Halcrowf66e8832008-04-29 00:59:51 -0700238static ssize_t
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700239ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count,
240 loff_t *ppos)
241{
242 struct ecryptfs_daemon *daemon;
243 struct ecryptfs_msg_ctx *msg_ctx;
244 size_t packet_length_size;
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700245 char packet_length[3];
246 size_t i;
247 size_t total_length;
David Howells4eea0352008-11-14 10:38:49 +1100248 uid_t euid = current_euid();
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700249 int rc;
250
251 mutex_lock(&ecryptfs_daemon_hash_mux);
252 /* TODO: Just use file->private_data? */
Serge Hallyn18b6e042008-10-15 16:38:45 -0500253 rc = ecryptfs_find_daemon_by_euid(&daemon, euid, current_user_ns());
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700254 BUG_ON(rc || !daemon);
255 mutex_lock(&daemon->mux);
256 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
257 rc = 0;
Cyrill Gorcunov43f14d82008-05-12 14:02:40 -0700258 mutex_unlock(&ecryptfs_daemon_hash_mux);
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700259 printk(KERN_WARNING "%s: Attempt to read from zombified "
260 "daemon\n", __func__);
261 goto out_unlock_daemon;
262 }
263 if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) {
264 rc = 0;
Cyrill Gorcunov43f14d82008-05-12 14:02:40 -0700265 mutex_unlock(&ecryptfs_daemon_hash_mux);
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700266 goto out_unlock_daemon;
267 }
268 /* This daemon will not go away so long as this flag is set */
269 daemon->flags |= ECRYPTFS_DAEMON_IN_READ;
270 mutex_unlock(&ecryptfs_daemon_hash_mux);
271check_list:
272 if (list_empty(&daemon->msg_ctx_out_queue)) {
273 mutex_unlock(&daemon->mux);
274 rc = wait_event_interruptible(
275 daemon->wait, !list_empty(&daemon->msg_ctx_out_queue));
276 mutex_lock(&daemon->mux);
277 if (rc < 0) {
278 rc = 0;
279 goto out_unlock_daemon;
280 }
281 }
282 if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
283 rc = 0;
284 goto out_unlock_daemon;
285 }
286 if (list_empty(&daemon->msg_ctx_out_queue)) {
287 /* Something else jumped in since the
288 * wait_event_interruptable() and removed the
289 * message from the queue; try again */
290 goto check_list;
291 }
David Howells4eea0352008-11-14 10:38:49 +1100292 BUG_ON(euid != daemon->euid);
Serge Hallyn18b6e042008-10-15 16:38:45 -0500293 BUG_ON(current_user_ns() != daemon->user_ns);
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700294 BUG_ON(task_pid(current) != daemon->pid);
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700295 msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue,
296 struct ecryptfs_msg_ctx, daemon_out_list);
297 BUG_ON(!msg_ctx);
298 mutex_lock(&msg_ctx->mux);
299 if (msg_ctx->msg) {
300 rc = ecryptfs_write_packet_length(packet_length,
301 msg_ctx->msg_size,
302 &packet_length_size);
303 if (rc) {
304 rc = 0;
305 printk(KERN_WARNING "%s: Error writing packet length; "
306 "rc = [%d]\n", __func__, rc);
307 goto out_unlock_msg_ctx;
308 }
309 } else {
310 packet_length_size = 0;
311 msg_ctx->msg_size = 0;
312 }
313 /* miscdevfs packet format:
314 * Octet 0: Type
315 * Octets 1-4: network byte order msg_ctx->counter
316 * Octets 5-N0: Size of struct ecryptfs_message to follow
317 * Octets N0-N1: struct ecryptfs_message (including data)
318 *
319 * Octets 5-N1 not written if the packet type does not
320 * include a message */
321 total_length = (1 + 4 + packet_length_size + msg_ctx->msg_size);
322 if (count < total_length) {
323 rc = 0;
324 printk(KERN_WARNING "%s: Only given user buffer of "
325 "size [%Zd], but we need [%Zd] to read the "
326 "pending message\n", __func__, count, total_length);
327 goto out_unlock_msg_ctx;
328 }
Al Viro79bc12a2008-05-21 06:32:11 +0100329 rc = -EFAULT;
330 if (put_user(msg_ctx->type, buf))
331 goto out_unlock_msg_ctx;
332 if (put_user(cpu_to_be32(msg_ctx->counter), (__be32 __user *)(buf + 1)))
333 goto out_unlock_msg_ctx;
334 i = 5;
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700335 if (msg_ctx->msg) {
Al Viro79bc12a2008-05-21 06:32:11 +0100336 if (copy_to_user(&buf[i], packet_length, packet_length_size))
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700337 goto out_unlock_msg_ctx;
Al Viro79bc12a2008-05-21 06:32:11 +0100338 i += packet_length_size;
339 if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size))
340 goto out_unlock_msg_ctx;
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700341 i += msg_ctx->msg_size;
342 }
343 rc = i;
344 list_del(&msg_ctx->daemon_out_list);
345 kfree(msg_ctx->msg);
346 msg_ctx->msg = NULL;
347 /* We do not expect a reply from the userspace daemon for any
348 * message type other than ECRYPTFS_MSG_REQUEST */
349 if (msg_ctx->type != ECRYPTFS_MSG_REQUEST)
350 ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
351out_unlock_msg_ctx:
352 mutex_unlock(&msg_ctx->mux);
353out_unlock_daemon:
354 daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ;
355 mutex_unlock(&daemon->mux);
356 return rc;
357}
358
359/**
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700360 * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon
361 * @data: Bytes comprising struct ecryptfs_message
362 * @data_size: sizeof(struct ecryptfs_message) + data len
363 * @euid: Effective user id of miscdevess sending the miscdev response
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700364 * @user_ns: The namespace in which @euid applies
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700365 * @pid: Miscdevess id of miscdevess sending the miscdev response
366 * @seq: Sequence number for miscdev response packet
367 *
368 * Returns zero on success; non-zero otherwise
369 */
370static int ecryptfs_miscdev_response(char *data, size_t data_size,
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700371 uid_t euid, struct user_namespace *user_ns,
372 struct pid *pid, u32 seq)
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700373{
374 struct ecryptfs_message *msg = (struct ecryptfs_message *)data;
375 int rc;
376
377 if ((sizeof(*msg) + msg->data_len) != data_size) {
378 printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = "
379 "[%Zd]; data_size = [%Zd]. Invalid packet.\n", __func__,
380 (sizeof(*msg) + msg->data_len), data_size);
381 rc = -EINVAL;
382 goto out;
383 }
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700384 rc = ecryptfs_process_response(msg, euid, user_ns, pid, seq);
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700385 if (rc)
386 printk(KERN_ERR
387 "Error processing response message; rc = [%d]\n", rc);
388out:
389 return rc;
390}
391
392/**
393 * ecryptfs_miscdev_write - handle write to daemon miscdev handle
394 * @file: File for misc dev handle (ignored)
395 * @buf: Buffer containing user data
396 * @count: Amount of data in @buf
397 * @ppos: Pointer to offset in file (ignored)
398 *
399 * miscdevfs packet format:
400 * Octet 0: Type
401 * Octets 1-4: network byte order msg_ctx->counter (0's for non-response)
402 * Octets 5-N0: Size of struct ecryptfs_message to follow
403 * Octets N0-N1: struct ecryptfs_message (including data)
404 *
405 * Returns the number of bytes read from @buf
406 */
407static ssize_t
408ecryptfs_miscdev_write(struct file *file, const char __user *buf,
409 size_t count, loff_t *ppos)
410{
Al Viro79bc12a2008-05-21 06:32:11 +0100411 __be32 counter_nbo;
412 u32 seq;
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700413 size_t packet_size, packet_size_length, i;
414 ssize_t sz = 0;
415 char *data;
David Howells4eea0352008-11-14 10:38:49 +1100416 uid_t euid = current_euid();
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700417 int rc;
418
419 if (count == 0)
420 goto out;
421 data = kmalloc(count, GFP_KERNEL);
422 if (!data) {
423 printk(KERN_ERR "%s: Out of memory whilst attempting to "
424 "kmalloc([%Zd], GFP_KERNEL)\n", __func__, count);
425 goto out;
426 }
427 rc = copy_from_user(data, buf, count);
428 if (rc) {
429 printk(KERN_ERR "%s: copy_from_user returned error [%d]\n",
430 __func__, rc);
431 goto out_free;
432 }
433 sz = count;
434 i = 0;
435 switch (data[i++]) {
436 case ECRYPTFS_MSG_RESPONSE:
437 if (count < (1 + 4 + 1 + sizeof(struct ecryptfs_message))) {
438 printk(KERN_WARNING "%s: Minimum acceptable packet "
439 "size is [%Zd], but amount of data written is "
440 "only [%Zd]. Discarding response packet.\n",
441 __func__,
442 (1 + 4 + 1 + sizeof(struct ecryptfs_message)),
443 count);
444 goto out_free;
445 }
Al Viro79bc12a2008-05-21 06:32:11 +0100446 memcpy(&counter_nbo, &data[i], 4);
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700447 seq = be32_to_cpu(counter_nbo);
448 i += 4;
449 rc = ecryptfs_parse_packet_length(&data[i], &packet_size,
450 &packet_size_length);
451 if (rc) {
452 printk(KERN_WARNING "%s: Error parsing packet length; "
453 "rc = [%d]\n", __func__, rc);
454 goto out_free;
455 }
456 i += packet_size_length;
457 if ((1 + 4 + packet_size_length + packet_size) != count) {
458 printk(KERN_WARNING "%s: (1 + packet_size_length([%Zd])"
459 " + packet_size([%Zd]))([%Zd]) != "
460 "count([%Zd]). Invalid packet format.\n",
461 __func__, packet_size_length, packet_size,
462 (1 + packet_size_length + packet_size), count);
463 goto out_free;
464 }
465 rc = ecryptfs_miscdev_response(&data[i], packet_size,
Serge Hallyn18b6e042008-10-15 16:38:45 -0500466 euid, current_user_ns(),
Michael Halcrow6a3fd922008-04-29 00:59:52 -0700467 task_pid(current), seq);
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700468 if (rc)
469 printk(KERN_WARNING "%s: Failed to deliver miscdev "
470 "response to requesting operation; rc = [%d]\n",
471 __func__, rc);
472 break;
473 case ECRYPTFS_MSG_HELO:
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700474 case ECRYPTFS_MSG_QUIT:
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700475 break;
476 default:
477 ecryptfs_printk(KERN_WARNING, "Dropping miscdev "
478 "message of unrecognized type [%d]\n",
479 data[0]);
480 break;
481 }
482out_free:
483 kfree(data);
484out:
485 return sz;
486}
487
488
489static const struct file_operations ecryptfs_miscdev_fops = {
490 .open = ecryptfs_miscdev_open,
491 .poll = ecryptfs_miscdev_poll,
492 .read = ecryptfs_miscdev_read,
493 .write = ecryptfs_miscdev_write,
494 .release = ecryptfs_miscdev_release,
495};
496
497static struct miscdevice ecryptfs_miscdev = {
498 .minor = MISC_DYNAMIC_MINOR,
499 .name = "ecryptfs",
500 .fops = &ecryptfs_miscdev_fops
501};
502
503/**
504 * ecryptfs_init_ecryptfs_miscdev
505 *
506 * Messages sent to the userspace daemon from the kernel are placed on
507 * a queue associated with the daemon. The next read against the
508 * miscdev handle by that daemon will return the oldest message placed
509 * on the message queue for the daemon.
510 *
511 * Returns zero on success; non-zero otherwise
512 */
513int ecryptfs_init_ecryptfs_miscdev(void)
514{
515 int rc;
516
517 atomic_set(&ecryptfs_num_miscdev_opens, 0);
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700518 rc = misc_register(&ecryptfs_miscdev);
519 if (rc)
520 printk(KERN_ERR "%s: Failed to register miscellaneous device "
521 "for communications with userspace daemons; rc = [%d]\n",
522 __func__, rc);
Michael Halcrow8bf2deb2008-04-29 00:59:50 -0700523 return rc;
524}
525
526/**
527 * ecryptfs_destroy_ecryptfs_miscdev
528 *
529 * All of the daemons must be exorcised prior to calling this
530 * function.
531 */
532void ecryptfs_destroy_ecryptfs_miscdev(void)
533{
534 BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0);
535 misc_deregister(&ecryptfs_miscdev);
536}