| 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 | |