Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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> |
Alexey Dobriyan | a99bbaf | 2009-10-04 16:11:37 +0400 | [diff] [blame] | 46 | #include <linux/sched.h> |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 54 | #include <linux/slab.h> |
Bastian Blank | 2fb3683 | 2011-12-10 19:29:47 +0100 | [diff] [blame] | 55 | #include <linux/miscdevice.h> |
| 56 | #include <linux/module.h> |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 57 | |
Bastian Blank | 2fb3683 | 2011-12-10 19:29:47 +0100 | [diff] [blame] | 58 | #include "xenbus_comms.h" |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 59 | |
| 60 | #include <xen/xenbus.h> |
Konrad Rzeszutek Wilk | b79d2ff | 2011-12-19 15:08:15 -0500 | [diff] [blame] | 61 | #include <xen/xen.h> |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 62 | #include <asm/xen/hypervisor.h> |
| 63 | |
Bastian Blank | 2fb3683 | 2011-12-10 19:29:47 +0100 | [diff] [blame] | 64 | MODULE_LICENSE("GPL"); |
| 65 | |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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; |
Ian Campbell | 50bf737 | 2012-01-04 11:39:51 +0000 | [diff] [blame] | 108 | char buffer[XENSTORE_PAYLOAD_MAX]; |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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); |
Daniel De Graaf | 7808121 | 2010-09-08 18:10:42 -0400 | [diff] [blame] | 129 | again: |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 130 | while (list_empty(&u->read_buffers)) { |
| 131 | mutex_unlock(&u->reply_mutex); |
Paolo Bonzini | 6280f19 | 2010-06-23 18:30:15 +0200 | [diff] [blame] | 132 | if (filp->f_flags & O_NONBLOCK) |
| 133 | return -EAGAIN; |
| 134 | |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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 | |
Jeremy Fitzhardinge | fb27cfb | 2010-08-25 12:19:53 -0700 | [diff] [blame] | 152 | if (ret != 0) { |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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 | } |
Daniel De Graaf | 7808121 | 2010-09-08 18:10:42 -0400 | [diff] [blame] | 168 | if (i == 0) |
| 169 | goto again; |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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 | { |
Ian Campbell | e88a0fa | 2009-01-24 08:22:47 +0000 | [diff] [blame] | 306 | int rc; |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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); |
Ian Campbell | e88a0fa | 2009-01-24 08:22:47 +0000 | [diff] [blame] | 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) { |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 345 | list_splice_tail(&staging_q, &u->read_buffers); |
| 346 | wake_up(&u->read_waitq); |
| 347 | } else { |
| 348 | queue_cleanup(&staging_q); |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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++; |
Jan Beulich | a43a5cc | 2012-01-24 13:52:42 +0000 | [diff] [blame] | 372 | if (memchr(token, 0, u->u.msg.len - (token - path)) == NULL) { |
| 373 | rc = -EILSEQ; |
| 374 | goto out; |
| 375 | } |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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)); |
Daniel De Graaf | 76ce761 | 2010-09-07 11:42:18 -0400 | [diff] [blame] | 421 | wake_up(&u->read_waitq); |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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 */ |
Jan Beulich | 1bcaba51 | 2012-10-17 13:14:09 -0400 | [diff] [blame] | 461 | if (len > sizeof(u->u.buffer) - u->len) { |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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 | |
Jeremy Fitzhardinge | fb27cfb | 2010-08-25 12:19:53 -0700 | [diff] [blame] | 470 | if (ret != 0) { |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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) { |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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: |
Diego Ongaro | 6d6df2e | 2010-09-01 09:18:54 -0700 | [diff] [blame] | 510 | /* Send out a transaction */ |
| 511 | ret = xenbus_write_transaction(msg_type, u); |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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; |
Daniel De Graaf | 6a5b3be | 2010-12-20 14:56:09 -0800 | [diff] [blame] | 556 | struct read_buffer *rb, *tmp_rb; |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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 | |
Daniel De Graaf | 6a5b3be | 2010-12-20 14:56:09 -0800 | [diff] [blame] | 575 | list_for_each_entry_safe(rb, tmp_rb, &u->read_buffers, list) { |
| 576 | list_del(&rb->list); |
| 577 | kfree(rb); |
| 578 | } |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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 | |
Bastian Blank | 2fb3683 | 2011-12-10 19:29:47 +0100 | [diff] [blame] | 594 | const struct file_operations xen_xenbus_fops = { |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 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, |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 600 | .llseek = no_llseek, |
Alex Zeffertt | 1107ba8 | 2009-01-07 18:07:11 -0800 | [diff] [blame] | 601 | }; |
Bastian Blank | 2fb3683 | 2011-12-10 19:29:47 +0100 | [diff] [blame] | 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) |
Bastian Blank | fe7acdb | 2011-12-10 19:29:50 +0100 | [diff] [blame] | 619 | printk(KERN_ERR "Could not register xenbus frontend device\n"); |
Bastian Blank | 2fb3683 | 2011-12-10 19:29:47 +0100 | [diff] [blame] | 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); |