1 | /* $NetBSD: xenbus_xs.c,v 1.23 2012/11/28 16:26:59 royger Exp $ */ |
2 | /****************************************************************************** |
3 | * xenbus_xs.c |
4 | * |
5 | * This is the kernel equivalent of the "xs" library. We don't need everything |
6 | * and we use xenbus_comms for communication. |
7 | * |
8 | * Copyright (C) 2005 Rusty Russell, IBM Corporation |
9 | * |
10 | * This file may be distributed separately from the Linux kernel, or |
11 | * incorporated into other software packages, subject to the following license: |
12 | * |
13 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
14 | * of this source file (the "Software"), to deal in the Software without |
15 | * restriction, including without limitation the rights to use, copy, modify, |
16 | * merge, publish, distribute, sublicense, and/or sell copies of the Software, |
17 | * and to permit persons to whom the Software is furnished to do so, subject to |
18 | * the following conditions: |
19 | * |
20 | * The above copyright notice and this permission notice shall be included in |
21 | * all copies or substantial portions of the Software. |
22 | * |
23 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
24 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
25 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
26 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
27 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
28 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
29 | * IN THE SOFTWARE. |
30 | */ |
31 | |
32 | #include <sys/cdefs.h> |
33 | __KERNEL_RCSID(0, "$NetBSD: xenbus_xs.c,v 1.23 2012/11/28 16:26:59 royger Exp $" ); |
34 | |
35 | #if 0 |
36 | #define DPRINTK(fmt, args...) \ |
37 | printf("xenbus_xs (%s:%d) " fmt ".\n", __func__, __LINE__, ##args) |
38 | #else |
39 | #define DPRINTK(fmt, args...) ((void)0) |
40 | #endif |
41 | |
42 | #include <sys/types.h> |
43 | #include <sys/null.h> |
44 | #include <sys/errno.h> |
45 | #include <sys/malloc.h> |
46 | #include <sys/systm.h> |
47 | #include <sys/param.h> |
48 | #include <sys/proc.h> |
49 | #include <sys/mutex.h> |
50 | #include <sys/kthread.h> |
51 | |
52 | #include <xen/xen.h> /* for xendomain_is_dom0() */ |
53 | #include <xen/xenbus.h> |
54 | #include "xenbus_comms.h" |
55 | |
56 | #define streq(a, b) (strcmp((a), (b)) == 0) |
57 | |
58 | struct xs_stored_msg { |
59 | SIMPLEQ_ENTRY(xs_stored_msg) msg_next; |
60 | |
61 | struct xsd_sockmsg hdr; |
62 | |
63 | union { |
64 | /* Queued replies. */ |
65 | struct { |
66 | char *body; |
67 | } reply; |
68 | |
69 | /* Queued watch events. */ |
70 | struct { |
71 | struct xenbus_watch *handle; |
72 | char **vec; |
73 | unsigned int vec_size; |
74 | } watch; |
75 | } u; |
76 | }; |
77 | |
78 | struct xs_handle { |
79 | /* A list of replies. Currently only one will ever be outstanding. */ |
80 | SIMPLEQ_HEAD(, xs_stored_msg) reply_list; |
81 | kmutex_t reply_lock; |
82 | kcondvar_t reply_cv; |
83 | kmutex_t xs_lock; /* serialize access to xenstore */ |
84 | int suspend_spl; |
85 | |
86 | }; |
87 | |
88 | static struct xs_handle xs_state; |
89 | |
90 | /* List of registered watches, and a lock to protect it. */ |
91 | static SLIST_HEAD(, xenbus_watch) watches; |
92 | static kmutex_t watches_lock; |
93 | |
94 | /* List of pending watch callback events, and a lock to protect it. */ |
95 | static SIMPLEQ_HEAD(, xs_stored_msg) watch_events; |
96 | static kmutex_t watch_events_lock; |
97 | static kcondvar_t watch_cv; |
98 | |
99 | static int |
100 | get_error(const char *errorstring) |
101 | { |
102 | unsigned int i; |
103 | |
104 | for (i = 0; !streq(errorstring, xsd_errors[i].errstring); i++) { |
105 | if (i == (sizeof(xsd_errors) / sizeof(xsd_errors[0]) - 1)) { |
106 | printf( |
107 | "XENBUS xen store gave: unknown error %s" , |
108 | errorstring); |
109 | return EINVAL; |
110 | } |
111 | } |
112 | return xsd_errors[i].errnum; |
113 | } |
114 | |
115 | static void * |
116 | read_reply(enum xsd_sockmsg_type *type, unsigned int *len) |
117 | { |
118 | struct xs_stored_msg *msg; |
119 | char *body; |
120 | |
121 | mutex_enter(&xs_state.reply_lock); |
122 | while (SIMPLEQ_EMPTY(&xs_state.reply_list)) { |
123 | cv_wait(&xs_state.reply_cv, &xs_state.reply_lock); |
124 | } |
125 | msg = SIMPLEQ_FIRST(&xs_state.reply_list); |
126 | SIMPLEQ_REMOVE_HEAD(&xs_state.reply_list, msg_next); |
127 | mutex_exit(&xs_state.reply_lock); |
128 | |
129 | *type = msg->hdr.type; |
130 | if (len) |
131 | *len = msg->hdr.len; |
132 | body = msg->u.reply.body; |
133 | DPRINTK("read_reply: type %d body %s" , |
134 | msg->hdr.type, body); |
135 | |
136 | free(msg, M_DEVBUF); |
137 | |
138 | return body; |
139 | } |
140 | |
141 | #if 0 |
142 | /* Emergency write. */ |
143 | void |
144 | xenbus_debug_write(const char *str, unsigned int count) |
145 | { |
146 | struct xsd_sockmsg msg = { 0 }; |
147 | |
148 | msg.type = XS_DEBUG; |
149 | msg.len = sizeof("print" ) + count + 1; |
150 | |
151 | xb_write(&msg, sizeof(msg)); |
152 | xb_write("print" , sizeof("print" )); |
153 | xb_write(str, count); |
154 | xb_write("" , 1); |
155 | } |
156 | #endif |
157 | |
158 | int |
159 | xenbus_dev_request_and_reply(struct xsd_sockmsg *msg, void**reply) |
160 | { |
161 | int err = 0, s; |
162 | |
163 | s = spltty(); |
164 | mutex_enter(&xs_state.xs_lock); |
165 | err = xb_write(msg, sizeof(*msg) + msg->len); |
166 | if (err) { |
167 | msg->type = XS_ERROR; |
168 | *reply = NULL; |
169 | } else { |
170 | *reply = read_reply(&msg->type, &msg->len); |
171 | } |
172 | mutex_exit(&xs_state.xs_lock); |
173 | splx(s); |
174 | |
175 | return err; |
176 | } |
177 | |
178 | /* Send message to xs, get kmalloc'ed reply. ERR_PTR() on error. */ |
179 | static int |
180 | xs_talkv(struct xenbus_transaction *t, |
181 | enum xsd_sockmsg_type type, |
182 | const struct iovec *iovec, |
183 | unsigned int num_vecs, |
184 | unsigned int *len, |
185 | char **retbuf) |
186 | { |
187 | struct xsd_sockmsg msg; |
188 | unsigned int i; |
189 | int err, s; |
190 | void *ret; |
191 | |
192 | msg.tx_id = (uint32_t)(unsigned long)t; |
193 | msg.req_id = 0; |
194 | msg.type = type; |
195 | msg.len = 0; |
196 | for (i = 0; i < num_vecs; i++) |
197 | msg.len += iovec[i].iov_len; |
198 | |
199 | s = spltty(); |
200 | mutex_enter(&xs_state.xs_lock); |
201 | |
202 | DPRINTK("write msg" ); |
203 | err = xb_write(&msg, sizeof(msg)); |
204 | DPRINTK("write msg err %d" , err); |
205 | if (err) { |
206 | mutex_exit(&xs_state.xs_lock); |
207 | splx(s); |
208 | return (err); |
209 | } |
210 | |
211 | for (i = 0; i < num_vecs; i++) { |
212 | DPRINTK("write iovect" ); |
213 | err = xb_write(iovec[i].iov_base, iovec[i].iov_len); |
214 | DPRINTK("write iovect err %d" , err); |
215 | if (err) { |
216 | mutex_exit(&xs_state.xs_lock); |
217 | splx(s); |
218 | return (err); |
219 | } |
220 | } |
221 | |
222 | DPRINTK("read" ); |
223 | ret = read_reply(&msg.type, len); |
224 | DPRINTK("read done" ); |
225 | |
226 | mutex_exit(&xs_state.xs_lock); |
227 | splx(s); |
228 | |
229 | if (msg.type == XS_ERROR) { |
230 | err = get_error(ret); |
231 | free(ret, M_DEVBUF); |
232 | return (err); |
233 | } |
234 | |
235 | KASSERT(msg.type == type); |
236 | if (retbuf != NULL) |
237 | *retbuf = ret; |
238 | else |
239 | free(ret, M_DEVBUF); |
240 | return 0; |
241 | } |
242 | |
243 | /* Simplified version of xs_talkv: single message. */ |
244 | static int |
245 | xs_single(struct xenbus_transaction *t, |
246 | enum xsd_sockmsg_type type, |
247 | const char *string, |
248 | unsigned int *len, |
249 | char **ret) |
250 | { |
251 | struct iovec iovec; |
252 | |
253 | /* xs_talkv only reads iovec */ |
254 | iovec.iov_base = __UNCONST(string); |
255 | iovec.iov_len = strlen(string) + 1; |
256 | return xs_talkv(t, type, &iovec, 1, len, ret); |
257 | } |
258 | |
259 | static unsigned int |
260 | count_strings(const char *strings, unsigned int len) |
261 | { |
262 | unsigned int num; |
263 | const char *p; |
264 | |
265 | for (p = strings, num = 0; p < strings + len; p += strlen(p) + 1) |
266 | num++; |
267 | |
268 | return num; |
269 | } |
270 | |
271 | /* Return the path to dir with /name appended. Buffer must be kfree()'ed. */ |
272 | static char * |
273 | join(const char *dir, const char *name) |
274 | { |
275 | char *buffer; |
276 | |
277 | buffer = malloc(strlen(dir) + strlen("/" ) + strlen(name) + 1, |
278 | M_DEVBUF, M_NOWAIT); |
279 | if (buffer == NULL) |
280 | return NULL; |
281 | |
282 | strcpy(buffer, dir); |
283 | if (!streq(name, "" )) { |
284 | strcat(buffer, "/" ); |
285 | strcat(buffer, name); |
286 | } |
287 | |
288 | return buffer; |
289 | } |
290 | |
291 | static char ** |
292 | split(char *strings, unsigned int len, unsigned int *num) |
293 | { |
294 | char *p, **ret; |
295 | |
296 | /* Count the strings. */ |
297 | *num = count_strings(strings, len); |
298 | |
299 | /* Transfer to one big alloc for easy freeing. */ |
300 | ret = malloc(*num * sizeof(char *) + len, M_DEVBUF, M_NOWAIT); |
301 | if (!ret) { |
302 | free(strings, M_DEVBUF); |
303 | return NULL; |
304 | } |
305 | memcpy(&ret[*num], strings, len); |
306 | free(strings, M_DEVBUF); |
307 | |
308 | strings = (char *)&ret[*num]; |
309 | for (p = strings, *num = 0; p < strings + len; p += strlen(p) + 1) |
310 | ret[(*num)++] = p; |
311 | |
312 | return ret; |
313 | } |
314 | |
315 | int |
316 | xenbus_directory(struct xenbus_transaction *t, |
317 | const char *dir, const char *node, unsigned int *num, |
318 | char ***retbuf) |
319 | { |
320 | char *strings, *path; |
321 | unsigned int len; |
322 | int err; |
323 | |
324 | path = join(dir, node); |
325 | if (path == NULL) |
326 | return ENOMEM; |
327 | |
328 | err = xs_single(t, XS_DIRECTORY, path, &len, &strings); |
329 | DPRINTK("xs_single %d %d" , err, len); |
330 | free(path, M_DEVBUF); |
331 | if (err) |
332 | return err; |
333 | |
334 | DPRINTK("xs_single strings %s" , strings); |
335 | *retbuf = split(strings, len, num); |
336 | if (*retbuf == NULL) |
337 | return ENOMEM; |
338 | return 0; |
339 | } |
340 | |
341 | /* Check if a path exists. Return 1 if it does. */ |
342 | int |
343 | xenbus_exists(struct xenbus_transaction *t, |
344 | const char *dir, const char *node) |
345 | { |
346 | char **d; |
347 | int dir_n, err; |
348 | |
349 | err = xenbus_directory(t, dir, node, &dir_n, &d); |
350 | if (err) |
351 | return 0; |
352 | free(d, M_DEVBUF); |
353 | return 1; |
354 | } |
355 | |
356 | /* Get the value of a single file. |
357 | * Returns a kmalloced value: call free() on it after use. |
358 | * len indicates length in bytes. |
359 | */ |
360 | int |
361 | xenbus_read(struct xenbus_transaction *t, |
362 | const char *dir, const char *node, unsigned int *len, |
363 | char **ret) |
364 | { |
365 | char *path; |
366 | int err; |
367 | |
368 | path = join(dir, node); |
369 | if (path == NULL) |
370 | return ENOMEM; |
371 | |
372 | err = xs_single(t, XS_READ, path, len, ret); |
373 | free(path, M_DEVBUF); |
374 | return err; |
375 | } |
376 | |
377 | /* Read a node and convert it to unsigned long. */ |
378 | int |
379 | xenbus_read_ul(struct xenbus_transaction *t, |
380 | const char *dir, const char *node, unsigned long *val, |
381 | int base) |
382 | { |
383 | char *string, *ep; |
384 | int err; |
385 | |
386 | err = xenbus_read(t, dir, node, NULL, &string); |
387 | if (err) |
388 | return err; |
389 | *val = strtoul(string, &ep, base); |
390 | if (*ep != '\0') { |
391 | free(string, M_DEVBUF); |
392 | return EFTYPE; |
393 | } |
394 | free(string, M_DEVBUF); |
395 | return 0; |
396 | } |
397 | |
398 | /* Read a node and convert it to unsigned long long. */ |
399 | int |
400 | xenbus_read_ull(struct xenbus_transaction *t, |
401 | const char *dir, const char *node, unsigned long long *val, |
402 | int base) |
403 | { |
404 | char *string, *ep; |
405 | int err; |
406 | |
407 | err = xenbus_read(t, dir, node, NULL, &string); |
408 | if (err) |
409 | return err; |
410 | *val = strtoull(string, &ep, base); |
411 | if (*ep != '\0') { |
412 | free(string, M_DEVBUF); |
413 | return EFTYPE; |
414 | } |
415 | free(string, M_DEVBUF); |
416 | return 0; |
417 | } |
418 | |
419 | /* Write the value of a single file. |
420 | * Returns -err on failure. |
421 | */ |
422 | int |
423 | xenbus_write(struct xenbus_transaction *t, |
424 | const char *dir, const char *node, const char *string) |
425 | { |
426 | const char *path; |
427 | struct iovec iovec[2]; |
428 | int ret; |
429 | |
430 | path = join(dir, node); |
431 | if (path == NULL) |
432 | return ENOMEM; |
433 | |
434 | /* xs_talkv only reads iovec */ |
435 | iovec[0].iov_base = __UNCONST(path); |
436 | iovec[0].iov_len = strlen(path) + 1; |
437 | iovec[1].iov_base = __UNCONST(string); |
438 | iovec[1].iov_len = strlen(string); |
439 | |
440 | ret = xs_talkv(t, XS_WRITE, iovec, 2, NULL, NULL); |
441 | return ret; |
442 | } |
443 | |
444 | /* Create a new directory. */ |
445 | int |
446 | xenbus_mkdir(struct xenbus_transaction *t, |
447 | const char *dir, const char *node) |
448 | { |
449 | char *path; |
450 | int ret; |
451 | |
452 | path = join(dir, node); |
453 | if (path == NULL) |
454 | return ENOMEM; |
455 | |
456 | ret = xs_single(t, XS_MKDIR, path, NULL, NULL); |
457 | free(path, M_DEVBUF); |
458 | return ret; |
459 | } |
460 | |
461 | /* Destroy a file or directory (directories must be empty). */ |
462 | int xenbus_rm(struct xenbus_transaction *t, const char *dir, const char *node) |
463 | { |
464 | char *path; |
465 | int ret; |
466 | |
467 | path = join(dir, node); |
468 | if (path == NULL) |
469 | return ENOMEM; |
470 | |
471 | ret = xs_single(t, XS_RM, path, NULL, NULL); |
472 | free(path, M_DEVBUF); |
473 | return ret; |
474 | } |
475 | |
476 | /* Start a transaction: changes by others will not be seen during this |
477 | * transaction, and changes will not be visible to others until end. |
478 | * MUST BE CALLED AT IPL_TTY ! |
479 | */ |
480 | struct xenbus_transaction * |
481 | xenbus_transaction_start(void) |
482 | { |
483 | char *id_str; |
484 | unsigned long id, err; |
485 | |
486 | err = xs_single(NULL, XS_TRANSACTION_START, "" , NULL, &id_str); |
487 | if (err) { |
488 | return NULL; |
489 | } |
490 | |
491 | id = strtoul(id_str, NULL, 0); |
492 | free(id_str, M_DEVBUF); |
493 | |
494 | return (struct xenbus_transaction *)id; |
495 | } |
496 | |
497 | /* End a transaction. |
498 | * If abandon is true, transaction is discarded instead of committed. |
499 | * MUST BE CALLED AT IPL_TTY ! |
500 | */ |
501 | int xenbus_transaction_end(struct xenbus_transaction *t, int abort) |
502 | { |
503 | char abortstr[2]; |
504 | int err; |
505 | |
506 | if (abort) |
507 | strcpy(abortstr, "F" ); |
508 | else |
509 | strcpy(abortstr, "T" ); |
510 | |
511 | err = xs_single(t, XS_TRANSACTION_END, abortstr, NULL, NULL); |
512 | |
513 | return err; |
514 | } |
515 | |
516 | /* Single read and scanf: returns -errno or num scanned. */ |
517 | int |
518 | xenbus_scanf(struct xenbus_transaction *t, |
519 | const char *dir, const char *node, const char *fmt, ...) |
520 | { |
521 | va_list ap; |
522 | int ret; |
523 | char *val; |
524 | |
525 | ret = xenbus_read(t, dir, node, NULL, &val); |
526 | if (ret) |
527 | return ret; |
528 | |
529 | va_start(ap, fmt); |
530 | //ret = vsscanf(val, fmt, ap); |
531 | ret = ENXIO; |
532 | printf("xb_scanf format %s in %s\n" , fmt, val); |
533 | va_end(ap); |
534 | free(val, M_DEVBUF); |
535 | return ret; |
536 | } |
537 | |
538 | /* Single printf and write: returns -errno or 0. */ |
539 | int |
540 | xenbus_printf(struct xenbus_transaction *t, |
541 | const char *dir, const char *node, const char *fmt, ...) |
542 | { |
543 | va_list ap; |
544 | int ret; |
545 | #define PRINTF_BUFFER_SIZE 4096 |
546 | char *printf_buffer; |
547 | |
548 | printf_buffer = malloc(PRINTF_BUFFER_SIZE, M_DEVBUF, M_NOWAIT); |
549 | if (printf_buffer == NULL) |
550 | return ENOMEM; |
551 | |
552 | va_start(ap, fmt); |
553 | ret = vsnprintf(printf_buffer, PRINTF_BUFFER_SIZE, fmt, ap); |
554 | va_end(ap); |
555 | |
556 | KASSERT(ret < PRINTF_BUFFER_SIZE); |
557 | ret = xenbus_write(t, dir, node, printf_buffer); |
558 | |
559 | free(printf_buffer, M_DEVBUF); |
560 | |
561 | return ret; |
562 | } |
563 | |
564 | /* Takes tuples of names, scanf-style args, and void **, NULL terminated. */ |
565 | int |
566 | xenbus_gather(struct xenbus_transaction *t, const char *dir, ...) |
567 | { |
568 | va_list ap; |
569 | const char *name; |
570 | int ret = 0; |
571 | |
572 | va_start(ap, dir); |
573 | while (ret == 0 && (name = va_arg(ap, char *)) != NULL) { |
574 | const char *fmt = va_arg(ap, char *); |
575 | void *result = va_arg(ap, void *); |
576 | char *p; |
577 | |
578 | ret = xenbus_read(t, dir, name, NULL, &p); |
579 | if (ret) |
580 | break; |
581 | if (fmt) { |
582 | // XXX if (sscanf(p, fmt, result) == 0) |
583 | ret = -EINVAL; |
584 | free(p, M_DEVBUF); |
585 | } else |
586 | *(char **)result = p; |
587 | } |
588 | va_end(ap); |
589 | return ret; |
590 | } |
591 | |
592 | static int |
593 | xs_watch(const char *path, const char *token) |
594 | { |
595 | struct iovec iov[2]; |
596 | |
597 | /* xs_talkv only reads iovec */ |
598 | iov[0].iov_base = __UNCONST(path); |
599 | iov[0].iov_len = strlen(path) + 1; |
600 | iov[1].iov_base = __UNCONST(token); |
601 | iov[1].iov_len = strlen(token) + 1; |
602 | |
603 | return xs_talkv(NULL, XS_WATCH, iov, 2, NULL, NULL); |
604 | } |
605 | |
606 | static int |
607 | xs_unwatch(const char *path, const char *token) |
608 | { |
609 | struct iovec iov[2]; |
610 | |
611 | /* xs_talkv only reads iovec */ |
612 | iov[0].iov_base = __UNCONST(path); |
613 | iov[0].iov_len = strlen(path) + 1; |
614 | iov[1].iov_base = __UNCONST(token); |
615 | iov[1].iov_len = strlen(token) + 1; |
616 | |
617 | return xs_talkv(NULL, XS_UNWATCH, iov, 2, NULL, NULL); |
618 | } |
619 | |
620 | static struct xenbus_watch * |
621 | find_watch(const char *token) |
622 | { |
623 | struct xenbus_watch *i, *cmp; |
624 | |
625 | cmp = (void *)strtoul(token, NULL, 16); |
626 | |
627 | SLIST_FOREACH(i, &watches, watch_next) { |
628 | if (i == cmp) |
629 | return i; |
630 | } |
631 | |
632 | return NULL; |
633 | } |
634 | |
635 | /* Register callback to watch this node. */ |
636 | int |
637 | register_xenbus_watch(struct xenbus_watch *watch) |
638 | { |
639 | /* Pointer in ascii is the token. */ |
640 | char token[sizeof(watch) * 2 + 1]; |
641 | int err; |
642 | |
643 | snprintf(token, sizeof(token), "%lX" , (long)watch); |
644 | |
645 | mutex_enter(&watches_lock); |
646 | KASSERT(find_watch(token) == 0); |
647 | SLIST_INSERT_HEAD(&watches, watch, watch_next); |
648 | mutex_exit(&watches_lock); |
649 | |
650 | err = xs_watch(watch->node, token); |
651 | |
652 | /* Ignore errors due to multiple registration. */ |
653 | if ((err != 0) && (err != EEXIST)) { |
654 | mutex_enter(&watches_lock); |
655 | SLIST_REMOVE(&watches, watch, xenbus_watch, watch_next); |
656 | mutex_exit(&watches_lock); |
657 | } |
658 | return err; |
659 | } |
660 | |
661 | void |
662 | unregister_xenbus_watch(struct xenbus_watch *watch) |
663 | { |
664 | SIMPLEQ_HEAD(, xs_stored_msg) gclist; |
665 | struct xs_stored_msg *msg, *next_msg; |
666 | char token[sizeof(watch) * 2 + 1]; |
667 | int err; |
668 | |
669 | snprintf(token, sizeof(token), "%lX" , (long)watch); |
670 | |
671 | mutex_enter(&watches_lock); |
672 | KASSERT(find_watch(token)); |
673 | SLIST_REMOVE(&watches, watch, xenbus_watch, watch_next); |
674 | mutex_exit(&watches_lock); |
675 | |
676 | err = xs_unwatch(watch->node, token); |
677 | if (err) { |
678 | printf( |
679 | "XENBUS Failed to release watch %s: %i\n" , |
680 | watch->node, err); |
681 | } |
682 | |
683 | /* Cancel pending watch events. */ |
684 | SIMPLEQ_INIT(&gclist); |
685 | mutex_enter(&watch_events_lock); |
686 | for (msg = SIMPLEQ_FIRST(&watch_events); msg != NULL; msg = next_msg) { |
687 | next_msg = SIMPLEQ_NEXT(msg, msg_next); |
688 | if (msg->u.watch.handle != watch) |
689 | continue; |
690 | SIMPLEQ_REMOVE(&watch_events, msg, xs_stored_msg, msg_next); |
691 | SIMPLEQ_INSERT_TAIL(&gclist, msg, msg_next); |
692 | } |
693 | mutex_exit(&watch_events_lock); |
694 | |
695 | while ((msg = SIMPLEQ_FIRST(&gclist)) != NULL) { |
696 | SIMPLEQ_REMOVE(&gclist, msg, xs_stored_msg, msg_next); |
697 | free(msg->u.watch.vec, M_DEVBUF); |
698 | free(msg, M_DEVBUF); |
699 | } |
700 | } |
701 | |
702 | void |
703 | xs_suspend(void) |
704 | { |
705 | xs_state.suspend_spl = spltty(); |
706 | } |
707 | |
708 | void |
709 | xs_resume(void) |
710 | { |
711 | struct xenbus_watch *watch; |
712 | char token[sizeof(watch) * 2 + 1]; |
713 | /* No need for watches_lock: the suspend_mutex is sufficient. */ |
714 | SLIST_FOREACH(watch, &watches, watch_next) { |
715 | snprintf(token, sizeof(token), "%lX" , (long)watch); |
716 | xs_watch(watch->node, token); |
717 | } |
718 | |
719 | splx(xs_state.suspend_spl); |
720 | } |
721 | |
722 | static void |
723 | xenwatch_thread(void *unused) |
724 | { |
725 | SIMPLEQ_HEAD(, xs_stored_msg) events_to_proces; |
726 | struct xs_stored_msg *msg; |
727 | |
728 | SIMPLEQ_INIT(&events_to_proces); |
729 | for (;;) { |
730 | mutex_enter(&watch_events_lock); |
731 | while (SIMPLEQ_EMPTY(&watch_events)) |
732 | cv_wait(&watch_cv, &watch_events_lock); |
733 | SIMPLEQ_CONCAT(&events_to_proces, &watch_events); |
734 | mutex_exit(&watch_events_lock); |
735 | |
736 | DPRINTK("xenwatch_thread: processing events" ); |
737 | |
738 | while ((msg = SIMPLEQ_FIRST(&events_to_proces)) != NULL) { |
739 | DPRINTK("xenwatch_thread: got event" ); |
740 | SIMPLEQ_REMOVE_HEAD(&events_to_proces, msg_next); |
741 | msg->u.watch.handle->xbw_callback( |
742 | msg->u.watch.handle, |
743 | (void *)msg->u.watch.vec, |
744 | msg->u.watch.vec_size); |
745 | free(msg->u.watch.vec, M_DEVBUF); |
746 | free(msg, M_DEVBUF); |
747 | } |
748 | } |
749 | } |
750 | |
751 | static int |
752 | process_msg(void) |
753 | { |
754 | struct xs_stored_msg *msg, *s_msg; |
755 | char *body; |
756 | int err; |
757 | |
758 | msg = malloc(sizeof(*msg), M_DEVBUF, M_NOWAIT); |
759 | if (msg == NULL) |
760 | return ENOMEM; |
761 | |
762 | err = xb_read(&msg->hdr, sizeof(msg->hdr)); |
763 | DPRINTK("xb_read hdr %d" , err); |
764 | if (err) { |
765 | free(msg, M_DEVBUF); |
766 | return err; |
767 | } |
768 | |
769 | body = malloc(msg->hdr.len + 1, M_DEVBUF, M_NOWAIT); |
770 | if (body == NULL) { |
771 | free(msg, M_DEVBUF); |
772 | return ENOMEM; |
773 | } |
774 | |
775 | err = xb_read(body, msg->hdr.len); |
776 | DPRINTK("xb_read body %d" , err); |
777 | if (err) { |
778 | free(body, M_DEVBUF); |
779 | free(msg, M_DEVBUF); |
780 | return err; |
781 | } |
782 | body[msg->hdr.len] = '\0'; |
783 | |
784 | if (msg->hdr.type == XS_WATCH_EVENT) { |
785 | bool found, repeated; |
786 | |
787 | DPRINTK("process_msg: XS_WATCH_EVENT" ); |
788 | msg->u.watch.vec = split(body, msg->hdr.len, |
789 | &msg->u.watch.vec_size); |
790 | if (msg->u.watch.vec == NULL) { |
791 | free(msg, M_DEVBUF); |
792 | return ENOMEM; |
793 | } |
794 | |
795 | mutex_enter(&watches_lock); |
796 | msg->u.watch.handle = find_watch( |
797 | msg->u.watch.vec[XS_WATCH_TOKEN]); |
798 | found = (msg->u.watch.handle != NULL); |
799 | repeated = false; |
800 | if (found) { |
801 | mutex_enter(&watch_events_lock); |
802 | /* Don't add duplicate events to the queue of pending watches */ |
803 | SIMPLEQ_FOREACH(s_msg, &watch_events, msg_next) { |
804 | if (s_msg->u.watch.handle == msg->u.watch.handle) { |
805 | repeated = true; |
806 | break; |
807 | } |
808 | } |
809 | if (!repeated) { |
810 | SIMPLEQ_INSERT_TAIL(&watch_events, msg, msg_next); |
811 | cv_broadcast(&watch_cv); |
812 | } |
813 | mutex_exit(&watch_events_lock); |
814 | } |
815 | mutex_exit(&watches_lock); |
816 | if (!found || repeated) { |
817 | free(msg->u.watch.vec, M_DEVBUF); |
818 | free(msg, M_DEVBUF); |
819 | } |
820 | } else { |
821 | DPRINTK("process_msg: type %d body %s" , msg->hdr.type, body); |
822 | |
823 | msg->u.reply.body = body; |
824 | mutex_enter(&xs_state.reply_lock); |
825 | SIMPLEQ_INSERT_TAIL(&xs_state.reply_list, msg, msg_next); |
826 | cv_broadcast(&xs_state.reply_cv); |
827 | mutex_exit(&xs_state.reply_lock); |
828 | } |
829 | |
830 | return 0; |
831 | } |
832 | |
833 | static void |
834 | xenbus_thread(void *unused) |
835 | { |
836 | int err; |
837 | |
838 | for (;;) { |
839 | err = process_msg(); |
840 | if (err) |
841 | printk("XENBUS error %d while reading message\n" , err); |
842 | } |
843 | } |
844 | |
845 | int |
846 | xs_init(device_t dev) |
847 | { |
848 | int err; |
849 | |
850 | SLIST_INIT(&watches); |
851 | mutex_init(&watches_lock, MUTEX_DEFAULT, IPL_TTY); |
852 | |
853 | SIMPLEQ_INIT(&watch_events); |
854 | mutex_init(&watch_events_lock, MUTEX_DEFAULT, IPL_TTY); |
855 | cv_init(&watch_cv, "evtsq" ); |
856 | |
857 | SIMPLEQ_INIT(&xs_state.reply_list); |
858 | mutex_init(&xs_state.xs_lock, MUTEX_DEFAULT, IPL_NONE); |
859 | mutex_init(&xs_state.reply_lock, MUTEX_DEFAULT, IPL_TTY); |
860 | cv_init(&xs_state.reply_cv, "rplq" ); |
861 | |
862 | err = kthread_create(PRI_NONE, 0, NULL, xenwatch_thread, |
863 | NULL, NULL, "xenwatch" ); |
864 | if (err) { |
865 | aprint_error_dev(dev, "kthread_create(xenwatch): %d\n" , err); |
866 | return err; |
867 | } |
868 | |
869 | err = kthread_create(PRI_NONE, 0, NULL, xenbus_thread, |
870 | NULL, NULL, "xenbus" ); |
871 | if (err) { |
872 | aprint_error_dev(dev, "kthread_create(xenbus): %d\n" , err); |
873 | return err; |
874 | } |
875 | |
876 | return 0; |
877 | } |
878 | |
879 | /* |
880 | * Local variables: |
881 | * c-file-style: "linux" |
882 | * indent-tabs-mode: t |
883 | * c-indent-level: 8 |
884 | * c-basic-offset: 8 |
885 | * tab-width: 8 |
886 | * End: |
887 | */ |
888 | |