diff options
Diffstat (limited to 'drivers/xen/xenbus/xenbus_dev_frontend.c')
-rw-r--r-- | drivers/xen/xenbus/xenbus_dev_frontend.c | 629 |
1 files changed, 0 insertions, 629 deletions
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c deleted file mode 100644 index ac727028e65..00000000000 --- a/drivers/xen/xenbus/xenbus_dev_frontend.c +++ /dev/null | |||
@@ -1,629 +0,0 @@ | |||
1 | /* | ||
2 | * Driver giving user-space access to the kernel's xenbus connection | ||
3 | * to xenstore. | ||
4 | * | ||
5 | * Copyright (c) 2005, Christian Limpach | ||
6 | * Copyright (c) 2005, Rusty Russell, IBM Corporation | ||
7 | * | ||
8 | * This program is free software; you can redistribute it and/or | ||
9 | * modify it under the terms of the GNU General Public License version 2 | ||
10 | * as published by the Free Software Foundation; or, when distributed | ||
11 | * separately from the Linux kernel or incorporated into other | ||
12 | * software packages, subject to the following license: | ||
13 | * | ||
14 | * Permission is hereby granted, free of charge, to any person obtaining a copy | ||
15 | * of this source file (the "Software"), to deal in the Software without | ||
16 | * restriction, including without limitation the rights to use, copy, modify, | ||
17 | * merge, publish, distribute, sublicense, and/or sell copies of the Software, | ||
18 | * and to permit persons to whom the Software is furnished to do so, subject to | ||
19 | * the following conditions: | ||
20 | * | ||
21 | * The above copyright notice and this permission notice shall be included in | ||
22 | * all copies or substantial portions of the Software. | ||
23 | * | ||
24 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | ||
25 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | ||
26 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | ||
27 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | ||
28 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | ||
29 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | ||
30 | * IN THE SOFTWARE. | ||
31 | * | ||
32 | * Changes: | ||
33 | * 2008-10-07 Alex Zeffertt Replaced /proc/xen/xenbus with xenfs filesystem | ||
34 | * and /proc/xen compatibility mount point. | ||
35 | * Turned xenfs into a loadable module. | ||
36 | */ | ||
37 | |||
38 | #include <linux/kernel.h> | ||
39 | #include <linux/errno.h> | ||
40 | #include <linux/uio.h> | ||
41 | #include <linux/notifier.h> | ||
42 | #include <linux/wait.h> | ||
43 | #include <linux/fs.h> | ||
44 | #include <linux/poll.h> | ||
45 | #include <linux/mutex.h> | ||
46 | #include <linux/sched.h> | ||
47 | #include <linux/spinlock.h> | ||
48 | #include <linux/mount.h> | ||
49 | #include <linux/pagemap.h> | ||
50 | #include <linux/uaccess.h> | ||
51 | #include <linux/init.h> | ||
52 | #include <linux/namei.h> | ||
53 | #include <linux/string.h> | ||
54 | #include <linux/slab.h> | ||
55 | #include <linux/miscdevice.h> | ||
56 | #include <linux/module.h> | ||
57 | |||
58 | #include "xenbus_comms.h" | ||
59 | |||
60 | #include <xen/xenbus.h> | ||
61 | #include <xen/xen.h> | ||
62 | #include <asm/xen/hypervisor.h> | ||
63 | |||
64 | MODULE_LICENSE("GPL"); | ||
65 | |||
66 | /* | ||
67 | * An element of a list of outstanding transactions, for which we're | ||
68 | * still waiting a reply. | ||
69 | */ | ||
70 | struct xenbus_transaction_holder { | ||
71 | struct list_head list; | ||
72 | struct xenbus_transaction handle; | ||
73 | }; | ||
74 | |||
75 | /* | ||
76 | * A buffer of data on the queue. | ||
77 | */ | ||
78 | struct read_buffer { | ||
79 | struct list_head list; | ||
80 | unsigned int cons; | ||
81 | unsigned int len; | ||
82 | char msg[]; | ||
83 | }; | ||
84 | |||
85 | struct xenbus_file_priv { | ||
86 | /* | ||
87 | * msgbuffer_mutex is held while partial requests are built up | ||
88 | * and complete requests are acted on. It therefore protects | ||
89 | * the "transactions" and "watches" lists, and the partial | ||
90 | * request length and buffer. | ||
91 | * | ||
92 | * reply_mutex protects the reply being built up to return to | ||
93 | * usermode. It nests inside msgbuffer_mutex but may be held | ||
94 | * alone during a watch callback. | ||
95 | */ | ||
96 | struct mutex msgbuffer_mutex; | ||
97 | |||
98 | /* In-progress transactions */ | ||
99 | struct list_head transactions; | ||
100 | |||
101 | /* Active watches. */ | ||
102 | struct list_head watches; | ||
103 | |||
104 | /* Partial request. */ | ||
105 | unsigned int len; | ||
106 | union { | ||
107 | struct xsd_sockmsg msg; | ||
108 | char buffer[XENSTORE_PAYLOAD_MAX]; | ||
109 | } u; | ||
110 | |||
111 | /* Response queue. */ | ||
112 | struct mutex reply_mutex; | ||
113 | struct list_head read_buffers; | ||
114 | wait_queue_head_t read_waitq; | ||
115 | |||
116 | }; | ||
117 | |||
118 | /* Read out any raw xenbus messages queued up. */ | ||
119 | static ssize_t xenbus_file_read(struct file *filp, | ||
120 | char __user *ubuf, | ||
121 | size_t len, loff_t *ppos) | ||
122 | { | ||
123 | struct xenbus_file_priv *u = filp->private_data; | ||
124 | struct read_buffer *rb; | ||
125 | unsigned i; | ||
126 | int ret; | ||
127 | |||
128 | mutex_lock(&u->reply_mutex); | ||
129 | again: | ||
130 | while (list_empty(&u->read_buffers)) { | ||
131 | mutex_unlock(&u->reply_mutex); | ||
132 | if (filp->f_flags & O_NONBLOCK) | ||
133 | return -EAGAIN; | ||
134 | |||
135 | ret = wait_event_interruptible(u->read_waitq, | ||
136 | !list_empty(&u->read_buffers)); | ||
137 | if (ret) | ||
138 | return ret; | ||
139 | mutex_lock(&u->reply_mutex); | ||
140 | } | ||
141 | |||
142 | rb = list_entry(u->read_buffers.next, struct read_buffer, list); | ||
143 | i = 0; | ||
144 | while (i < len) { | ||
145 | unsigned sz = min((unsigned)len - i, rb->len - rb->cons); | ||
146 | |||
147 | ret = copy_to_user(ubuf + i, &rb->msg[rb->cons], sz); | ||
148 | |||
149 | i += sz - ret; | ||
150 | rb->cons += sz - ret; | ||
151 | |||
152 | if (ret != 0) { | ||
153 | if (i == 0) | ||
154 | i = -EFAULT; | ||
155 | goto out; | ||
156 | } | ||
157 | |||
158 | /* Clear out buffer if it has been consumed */ | ||
159 | if (rb->cons == rb->len) { | ||
160 | list_del(&rb->list); | ||
161 | kfree(rb); | ||
162 | if (list_empty(&u->read_buffers)) | ||
163 | break; | ||
164 | rb = list_entry(u->read_buffers.next, | ||
165 | struct read_buffer, list); | ||
166 | } | ||
167 | } | ||
168 | if (i == 0) | ||
169 | goto again; | ||
170 | |||
171 | out: | ||
172 | mutex_unlock(&u->reply_mutex); | ||
173 | return i; | ||
174 | } | ||
175 | |||
176 | /* | ||
177 | * Add a buffer to the queue. Caller must hold the appropriate lock | ||
178 | * if the queue is not local. (Commonly the caller will build up | ||
179 | * multiple queued buffers on a temporary local list, and then add it | ||
180 | * to the appropriate list under lock once all the buffers have een | ||
181 | * successfully allocated.) | ||
182 | */ | ||
183 | static int queue_reply(struct list_head *queue, const void *data, size_t len) | ||
184 | { | ||
185 | struct read_buffer *rb; | ||
186 | |||
187 | if (len == 0) | ||
188 | return 0; | ||
189 | |||
190 | rb = kmalloc(sizeof(*rb) + len, GFP_KERNEL); | ||
191 | if (rb == NULL) | ||
192 | return -ENOMEM; | ||
193 | |||
194 | rb->cons = 0; | ||
195 | rb->len = len; | ||
196 | |||
197 | memcpy(rb->msg, data, len); | ||
198 | |||
199 | list_add_tail(&rb->list, queue); | ||
200 | return 0; | ||
201 | } | ||
202 | |||
203 | /* | ||
204 | * Free all the read_buffer s on a list. | ||
205 | * Caller must have sole reference to list. | ||
206 | */ | ||
207 | static void queue_cleanup(struct list_head *list) | ||
208 | { | ||
209 | struct read_buffer *rb; | ||
210 | |||
211 | while (!list_empty(list)) { | ||
212 | rb = list_entry(list->next, struct read_buffer, list); | ||
213 | list_del(list->next); | ||
214 | kfree(rb); | ||
215 | } | ||
216 | } | ||
217 | |||
218 | struct watch_adapter { | ||
219 | struct list_head list; | ||
220 | struct xenbus_watch watch; | ||
221 | struct xenbus_file_priv *dev_data; | ||
222 | char *token; | ||
223 | }; | ||
224 | |||
225 | static void free_watch_adapter(struct watch_adapter *watch) | ||
226 | { | ||
227 | kfree(watch->watch.node); | ||
228 | kfree(watch->token); | ||
229 | kfree(watch); | ||
230 | } | ||
231 | |||
232 | static struct watch_adapter *alloc_watch_adapter(const char *path, | ||
233 | const char *token) | ||
234 | { | ||
235 | struct watch_adapter *watch; | ||
236 | |||
237 | watch = kzalloc(sizeof(*watch), GFP_KERNEL); | ||
238 | if (watch == NULL) | ||
239 | goto out_fail; | ||
240 | |||
241 | watch->watch.node = kstrdup(path, GFP_KERNEL); | ||
242 | if (watch->watch.node == NULL) | ||
243 | goto out_free; | ||
244 | |||
245 | watch->token = kstrdup(token, GFP_KERNEL); | ||
246 | if (watch->token == NULL) | ||
247 | goto out_free; | ||
248 | |||
249 | return watch; | ||
250 | |||
251 | out_free: | ||
252 | free_watch_adapter(watch); | ||
253 | |||
254 | out_fail: | ||
255 | return NULL; | ||
256 | } | ||
257 | |||
258 | static void watch_fired(struct xenbus_watch *watch, | ||
259 | const char **vec, | ||
260 | unsigned int len) | ||
261 | { | ||
262 | struct watch_adapter *adap; | ||
263 | struct xsd_sockmsg hdr; | ||
264 | const char *path, *token; | ||
265 | int path_len, tok_len, body_len, data_len = 0; | ||
266 | int ret; | ||
267 | LIST_HEAD(staging_q); | ||
268 | |||
269 | adap = container_of(watch, struct watch_adapter, watch); | ||
270 | |||
271 | path = vec[XS_WATCH_PATH]; | ||
272 | token = adap->token; | ||
273 | |||
274 | path_len = strlen(path) + 1; | ||
275 | tok_len = strlen(token) + 1; | ||
276 | if (len > 2) | ||
277 | data_len = vec[len] - vec[2] + 1; | ||
278 | body_len = path_len + tok_len + data_len; | ||
279 | |||
280 | hdr.type = XS_WATCH_EVENT; | ||
281 | hdr.len = body_len; | ||
282 | |||
283 | mutex_lock(&adap->dev_data->reply_mutex); | ||
284 | |||
285 | ret = queue_reply(&staging_q, &hdr, sizeof(hdr)); | ||
286 | if (!ret) | ||
287 | ret = queue_reply(&staging_q, path, path_len); | ||
288 | if (!ret) | ||
289 | ret = queue_reply(&staging_q, token, tok_len); | ||
290 | if (!ret && len > 2) | ||
291 | ret = queue_reply(&staging_q, vec[2], data_len); | ||
292 | |||
293 | if (!ret) { | ||
294 | /* success: pass reply list onto watcher */ | ||
295 | list_splice_tail(&staging_q, &adap->dev_data->read_buffers); | ||
296 | wake_up(&adap->dev_data->read_waitq); | ||
297 | } else | ||
298 | queue_cleanup(&staging_q); | ||
299 | |||
300 | mutex_unlock(&adap->dev_data->reply_mutex); | ||
301 | } | ||
302 | |||
303 | static int xenbus_write_transaction(unsigned msg_type, | ||
304 | struct xenbus_file_priv *u) | ||
305 | { | ||
306 | int rc; | ||
307 | void *reply; | ||
308 | struct xenbus_transaction_holder *trans = NULL; | ||
309 | LIST_HEAD(staging_q); | ||
310 | |||
311 | if (msg_type == XS_TRANSACTION_START) { | ||
312 | trans = kmalloc(sizeof(*trans), GFP_KERNEL); | ||
313 | if (!trans) { | ||
314 | rc = -ENOMEM; | ||
315 | goto out; | ||
316 | } | ||
317 | } | ||
318 | |||
319 | reply = xenbus_dev_request_and_reply(&u->u.msg); | ||
320 | if (IS_ERR(reply)) { | ||
321 | kfree(trans); | ||
322 | rc = PTR_ERR(reply); | ||
323 | goto out; | ||
324 | } | ||
325 | |||
326 | if (msg_type == XS_TRANSACTION_START) { | ||
327 | trans->handle.id = simple_strtoul(reply, NULL, 0); | ||
328 | |||
329 | list_add(&trans->list, &u->transactions); | ||
330 | } else if (msg_type == XS_TRANSACTION_END) { | ||
331 | list_for_each_entry(trans, &u->transactions, list) | ||
332 | if (trans->handle.id == u->u.msg.tx_id) | ||
333 | break; | ||
334 | BUG_ON(&trans->list == &u->transactions); | ||
335 | list_del(&trans->list); | ||
336 | |||
337 | kfree(trans); | ||
338 | } | ||
339 | |||
340 | mutex_lock(&u->reply_mutex); | ||
341 | rc = queue_reply(&staging_q, &u->u.msg, sizeof(u->u.msg)); | ||
342 | if (!rc) | ||
343 | rc = queue_reply(&staging_q, reply, u->u.msg.len); | ||
344 | if (!rc) { | ||
345 | list_splice_tail(&staging_q, &u->read_buffers); | ||
346 | wake_up(&u->read_waitq); | ||
347 | } else { | ||
348 | queue_cleanup(&staging_q); | ||
349 | } | ||
350 | mutex_unlock(&u->reply_mutex); | ||
351 | |||
352 | kfree(reply); | ||
353 | |||
354 | out: | ||
355 | return rc; | ||
356 | } | ||
357 | |||
358 | static int xenbus_write_watch(unsigned msg_type, struct xenbus_file_priv *u) | ||
359 | { | ||
360 | struct watch_adapter *watch, *tmp_watch; | ||
361 | char *path, *token; | ||
362 | int err, rc; | ||
363 | LIST_HEAD(staging_q); | ||
364 | |||
365 | path = u->u.buffer + sizeof(u->u.msg); | ||
366 | token = memchr(path, 0, u->u.msg.len); | ||
367 | if (token == NULL) { | ||
368 | rc = -EILSEQ; | ||
369 | goto out; | ||
370 | } | ||
371 | token++; | ||
372 | if (memchr(token, 0, u->u.msg.len - (token - path)) == NULL) { | ||
373 | rc = -EILSEQ; | ||
374 | goto out; | ||
375 | } | ||
376 | |||
377 | if (msg_type == XS_WATCH) { | ||
378 | watch = alloc_watch_adapter(path, token); | ||
379 | if (watch == NULL) { | ||
380 | rc = -ENOMEM; | ||
381 | goto out; | ||
382 | } | ||
383 | |||
384 | watch->watch.callback = watch_fired; | ||
385 | watch->dev_data = u; | ||
386 | |||
387 | err = register_xenbus_watch(&watch->watch); | ||
388 | if (err) { | ||
389 | free_watch_adapter(watch); | ||
390 | rc = err; | ||
391 | goto out; | ||
392 | } | ||
393 | list_add(&watch->list, &u->watches); | ||
394 | } else { | ||
395 | list_for_each_entry_safe(watch, tmp_watch, &u->watches, list) { | ||
396 | if (!strcmp(watch->token, token) && | ||
397 | !strcmp(watch->watch.node, path)) { | ||
398 | unregister_xenbus_watch(&watch->watch); | ||
399 | list_del(&watch->list); | ||
400 | free_watch_adapter(watch); | ||
401 | break; | ||
402 | } | ||
403 | } | ||
404 | } | ||
405 | |||
406 | /* Success. Synthesize a reply to say all is OK. */ | ||
407 | { | ||
408 | struct { | ||
409 | struct xsd_sockmsg hdr; | ||
410 | char body[3]; | ||
411 | } __packed reply = { | ||
412 | { | ||
413 | .type = msg_type, | ||
414 | .len = sizeof(reply.body) | ||
415 | }, | ||
416 | "OK" | ||
417 | }; | ||
418 | |||
419 | mutex_lock(&u->reply_mutex); | ||
420 | rc = queue_reply(&u->read_buffers, &reply, sizeof(reply)); | ||
421 | wake_up(&u->read_waitq); | ||
422 | mutex_unlock(&u->reply_mutex); | ||
423 | } | ||
424 | |||
425 | out: | ||
426 | return rc; | ||
427 | } | ||
428 | |||
429 | static ssize_t xenbus_file_write(struct file *filp, | ||
430 | const char __user *ubuf, | ||
431 | size_t len, loff_t *ppos) | ||
432 | { | ||
433 | struct xenbus_file_priv *u = filp->private_data; | ||
434 | uint32_t msg_type; | ||
435 | int rc = len; | ||
436 | int ret; | ||
437 | LIST_HEAD(staging_q); | ||
438 | |||
439 | /* | ||
440 | * We're expecting usermode to be writing properly formed | ||
441 | * xenbus messages. If they write an incomplete message we | ||
442 | * buffer it up. Once it is complete, we act on it. | ||
443 | */ | ||
444 | |||
445 | /* | ||
446 | * Make sure concurrent writers can't stomp all over each | ||
447 | * other's messages and make a mess of our partial message | ||
448 | * buffer. We don't make any attemppt to stop multiple | ||
449 | * writers from making a mess of each other's incomplete | ||
450 | * messages; we're just trying to guarantee our own internal | ||
451 | * consistency and make sure that single writes are handled | ||
452 | * atomically. | ||
453 | */ | ||
454 | mutex_lock(&u->msgbuffer_mutex); | ||
455 | |||
456 | /* Get this out of the way early to avoid confusion */ | ||
457 | if (len == 0) | ||
458 | goto out; | ||
459 | |||
460 | /* Can't write a xenbus message larger we can buffer */ | ||
461 | if (len > sizeof(u->u.buffer) - u->len) { | ||
462 | /* On error, dump existing buffer */ | ||
463 | u->len = 0; | ||
464 | rc = -EINVAL; | ||
465 | goto out; | ||
466 | } | ||
467 | |||
468 | ret = copy_from_user(u->u.buffer + u->len, ubuf, len); | ||
469 | |||
470 | if (ret != 0) { | ||
471 | rc = -EFAULT; | ||
472 | goto out; | ||
473 | } | ||
474 | |||
475 | /* Deal with a partial copy. */ | ||
476 | len -= ret; | ||
477 | rc = len; | ||
478 | |||
479 | u->len += len; | ||
480 | |||
481 | /* Return if we haven't got a full message yet */ | ||
482 | if (u->len < sizeof(u->u.msg)) | ||
483 | goto out; /* not even the header yet */ | ||
484 | |||
485 | /* If we're expecting a message that's larger than we can | ||
486 | possibly send, dump what we have and return an error. */ | ||
487 | if ((sizeof(u->u.msg) + u->u.msg.len) > sizeof(u->u.buffer)) { | ||
488 | rc = -E2BIG; | ||
489 | u->len = 0; | ||
490 | goto out; | ||
491 | } | ||
492 | |||
493 | if (u->len < (sizeof(u->u.msg) + u->u.msg.len)) | ||
494 | goto out; /* incomplete data portion */ | ||
495 | |||
496 | /* | ||
497 | * OK, now we have a complete message. Do something with it. | ||
498 | */ | ||
499 | |||
500 | msg_type = u->u.msg.type; | ||
501 | |||
502 | switch (msg_type) { | ||
503 | case XS_WATCH: | ||
504 | case XS_UNWATCH: | ||
505 | /* (Un)Ask for some path to be watched for changes */ | ||
506 | ret = xenbus_write_watch(msg_type, u); | ||
507 | break; | ||
508 | |||
509 | default: | ||
510 | /* Send out a transaction */ | ||
511 | ret = xenbus_write_transaction(msg_type, u); | ||
512 | break; | ||
513 | } | ||
514 | if (ret != 0) | ||
515 | rc = ret; | ||
516 | |||
517 | /* Buffered message consumed */ | ||
518 | u->len = 0; | ||
519 | |||
520 | out: | ||
521 | mutex_unlock(&u->msgbuffer_mutex); | ||
522 | return rc; | ||
523 | } | ||
524 | |||
525 | static int xenbus_file_open(struct inode *inode, struct file *filp) | ||
526 | { | ||
527 | struct xenbus_file_priv *u; | ||
528 | |||
529 | if (xen_store_evtchn == 0) | ||
530 | return -ENOENT; | ||
531 | |||
532 | nonseekable_open(inode, filp); | ||
533 | |||
534 | u = kzalloc(sizeof(*u), GFP_KERNEL); | ||
535 | if (u == NULL) | ||
536 | return -ENOMEM; | ||
537 | |||
538 | INIT_LIST_HEAD(&u->transactions); | ||
539 | INIT_LIST_HEAD(&u->watches); | ||
540 | INIT_LIST_HEAD(&u->read_buffers); | ||
541 | init_waitqueue_head(&u->read_waitq); | ||
542 | |||
543 | mutex_init(&u->reply_mutex); | ||
544 | mutex_init(&u->msgbuffer_mutex); | ||
545 | |||
546 | filp->private_data = u; | ||
547 | |||
548 | return 0; | ||
549 | } | ||
550 | |||
551 | static int xenbus_file_release(struct inode *inode, struct file *filp) | ||
552 | { | ||
553 | struct xenbus_file_priv *u = filp->private_data; | ||
554 | struct xenbus_transaction_holder *trans, *tmp; | ||
555 | struct watch_adapter *watch, *tmp_watch; | ||
556 | struct read_buffer *rb, *tmp_rb; | ||
557 | |||
558 | /* | ||
559 | * No need for locking here because there are no other users, | ||
560 | * by definition. | ||
561 | */ | ||
562 | |||
563 | list_for_each_entry_safe(trans, tmp, &u->transactions, list) { | ||
564 | xenbus_transaction_end(trans->handle, 1); | ||
565 | list_del(&trans->list); | ||
566 | kfree(trans); | ||
567 | } | ||
568 | |||
569 | list_for_each_entry_safe(watch, tmp_watch, &u->watches, list) { | ||
570 | unregister_xenbus_watch(&watch->watch); | ||
571 | list_del(&watch->list); | ||
572 | free_watch_adapter(watch); | ||
573 | } | ||
574 | |||
575 | list_for_each_entry_safe(rb, tmp_rb, &u->read_buffers, list) { | ||
576 | list_del(&rb->list); | ||
577 | kfree(rb); | ||
578 | } | ||
579 | kfree(u); | ||
580 | |||
581 | return 0; | ||
582 | } | ||
583 | |||
584 | static unsigned int xenbus_file_poll(struct file *file, poll_table *wait) | ||
585 | { | ||
586 | struct xenbus_file_priv *u = file->private_data; | ||
587 | |||
588 | poll_wait(file, &u->read_waitq, wait); | ||
589 | if (!list_empty(&u->read_buffers)) | ||
590 | return POLLIN | POLLRDNORM; | ||
591 | return 0; | ||
592 | } | ||
593 | |||
594 | const struct file_operations xen_xenbus_fops = { | ||
595 | .read = xenbus_file_read, | ||
596 | .write = xenbus_file_write, | ||
597 | .open = xenbus_file_open, | ||
598 | .release = xenbus_file_release, | ||
599 | .poll = xenbus_file_poll, | ||
600 | .llseek = no_llseek, | ||
601 | }; | ||
602 | EXPORT_SYMBOL_GPL(xen_xenbus_fops); | ||
603 | |||
604 | static struct miscdevice xenbus_dev = { | ||
605 | .minor = MISC_DYNAMIC_MINOR, | ||
606 | .name = "xen/xenbus", | ||
607 | .fops = &xen_xenbus_fops, | ||
608 | }; | ||
609 | |||
610 | static int __init xenbus_init(void) | ||
611 | { | ||
612 | int err; | ||
613 | |||
614 | if (!xen_domain()) | ||
615 | return -ENODEV; | ||
616 | |||
617 | err = misc_register(&xenbus_dev); | ||
618 | if (err) | ||
619 | printk(KERN_ERR "Could not register xenbus frontend device\n"); | ||
620 | return err; | ||
621 | } | ||
622 | |||
623 | static void __exit xenbus_exit(void) | ||
624 | { | ||
625 | misc_deregister(&xenbus_dev); | ||
626 | } | ||
627 | |||
628 | module_init(xenbus_init); | ||
629 | module_exit(xenbus_exit); | ||