| 1 | /* |
| 2 | * Copyright (C) 2011 EfficiOS Inc. |
| 3 | * Copyright (C) 2019 Yannick Lamarre <ylamarre@efficios.com> |
| 4 | * |
| 5 | * SPDX-License-Identifier: LGPL-2.1-only |
| 6 | * |
| 7 | */ |
| 8 | |
| 9 | #define _LGPL_SOURCE |
| 10 | #include <assert.h> |
| 11 | #include <stdlib.h> |
| 12 | #include <stdbool.h> |
| 13 | |
| 14 | #include <common/defaults.h> |
| 15 | #include <common/error.h> |
| 16 | #include <common/macros.h> |
| 17 | #include <common/utils.h> |
| 18 | |
| 19 | #include "poll.h" |
| 20 | |
| 21 | #if HAVE_EPOLL |
| 22 | |
| 23 | #include <fcntl.h> |
| 24 | #include <limits.h> |
| 25 | #include <sys/types.h> |
| 26 | #include <sys/stat.h> |
| 27 | #include <unistd.h> |
| 28 | |
| 29 | /* |
| 30 | * Maximum number of fd we can monitor. |
| 31 | * |
| 32 | * For epoll(7), /proc/sys/fs/epoll/max_user_watches (since Linux 2.6.28) will |
| 33 | * be used for the maximum size of the poll set. If this interface is not |
| 34 | * available, according to the manpage, the max_user_watches value is 1/25 (4%) |
| 35 | * of the available low memory divided by the registration cost in bytes which |
| 36 | * is 90 bytes on a 32-bit kernel and 160 bytes on a 64-bit kernel. |
| 37 | * |
| 38 | */ |
| 39 | static unsigned int poll_max_size; |
| 40 | |
| 41 | /* |
| 42 | * Resize the epoll events structure of the new size. |
| 43 | * |
| 44 | * Return 0 on success or else -1 with the current events pointer untouched. |
| 45 | */ |
| 46 | static int resize_poll_event(struct lttng_poll_event *events, |
| 47 | uint32_t new_size) |
| 48 | { |
| 49 | struct epoll_event *ptr; |
| 50 | |
| 51 | assert(events); |
| 52 | |
| 53 | ptr = realloc(events->events, new_size * sizeof(*ptr)); |
| 54 | if (ptr == NULL) { |
| 55 | PERROR("realloc epoll add"); |
| 56 | goto error; |
| 57 | } |
| 58 | if (new_size > events->alloc_size) { |
| 59 | /* Zero newly allocated memory */ |
| 60 | memset(ptr + events->alloc_size, 0, |
| 61 | (new_size - events->alloc_size) * sizeof(*ptr)); |
| 62 | } |
| 63 | events->events = ptr; |
| 64 | events->alloc_size = new_size; |
| 65 | |
| 66 | return 0; |
| 67 | |
| 68 | error: |
| 69 | return -1; |
| 70 | } |
| 71 | |
| 72 | /* |
| 73 | * Create epoll set and allocate returned events structure. |
| 74 | */ |
| 75 | LTTNG_HIDDEN |
| 76 | int compat_epoll_create(struct lttng_poll_event *events, int size, int flags) |
| 77 | { |
| 78 | int ret; |
| 79 | |
| 80 | if (events == NULL || size <= 0) { |
| 81 | goto error; |
| 82 | } |
| 83 | |
| 84 | if (!poll_max_size) { |
| 85 | if (lttng_poll_set_max_size()) { |
| 86 | goto error; |
| 87 | } |
| 88 | } |
| 89 | |
| 90 | /* Don't bust the limit here */ |
| 91 | if (size > poll_max_size) { |
| 92 | size = poll_max_size; |
| 93 | } |
| 94 | |
| 95 | ret = compat_glibc_epoll_create(size, flags); |
| 96 | if (ret < 0) { |
| 97 | /* At this point, every error is fatal */ |
| 98 | PERROR("epoll_create1"); |
| 99 | goto error; |
| 100 | } |
| 101 | |
| 102 | events->epfd = ret; |
| 103 | |
| 104 | /* This *must* be freed by using lttng_poll_free() */ |
| 105 | events->events = zmalloc(size * sizeof(struct epoll_event)); |
| 106 | if (events->events == NULL) { |
| 107 | PERROR("zmalloc epoll set"); |
| 108 | goto error_close; |
| 109 | } |
| 110 | |
| 111 | events->alloc_size = events->init_size = size; |
| 112 | events->nb_fd = 0; |
| 113 | |
| 114 | return 0; |
| 115 | |
| 116 | error_close: |
| 117 | ret = close(events->epfd); |
| 118 | if (ret) { |
| 119 | PERROR("close"); |
| 120 | } |
| 121 | error: |
| 122 | return -1; |
| 123 | } |
| 124 | |
| 125 | /* |
| 126 | * Add a fd to the epoll set with requesting events. |
| 127 | */ |
| 128 | LTTNG_HIDDEN |
| 129 | int compat_epoll_add(struct lttng_poll_event *events, int fd, uint32_t req_events) |
| 130 | { |
| 131 | int ret; |
| 132 | struct epoll_event ev; |
| 133 | |
| 134 | if (events == NULL || events->events == NULL || fd < 0) { |
| 135 | ERR("Bad compat epoll add arguments"); |
| 136 | goto error; |
| 137 | } |
| 138 | |
| 139 | /* |
| 140 | * Zero struct epoll_event to ensure all representations of its |
| 141 | * union are zeroed. |
| 142 | */ |
| 143 | memset(&ev, 0, sizeof(ev)); |
| 144 | ev.events = req_events; |
| 145 | ev.data.fd = fd; |
| 146 | |
| 147 | ret = epoll_ctl(events->epfd, EPOLL_CTL_ADD, fd, &ev); |
| 148 | if (ret < 0) { |
| 149 | switch (errno) { |
| 150 | case EEXIST: |
| 151 | /* If exist, it's OK. */ |
| 152 | goto end; |
| 153 | case ENOSPC: |
| 154 | case EPERM: |
| 155 | /* Print PERROR and goto end not failing. Show must go on. */ |
| 156 | PERROR("epoll_ctl ADD"); |
| 157 | goto end; |
| 158 | default: |
| 159 | PERROR("epoll_ctl ADD fatal"); |
| 160 | goto error; |
| 161 | } |
| 162 | } |
| 163 | |
| 164 | events->nb_fd++; |
| 165 | |
| 166 | end: |
| 167 | return 0; |
| 168 | |
| 169 | error: |
| 170 | return -1; |
| 171 | } |
| 172 | |
| 173 | /* |
| 174 | * Remove a fd from the epoll set. |
| 175 | */ |
| 176 | LTTNG_HIDDEN |
| 177 | int compat_epoll_del(struct lttng_poll_event *events, int fd) |
| 178 | { |
| 179 | int ret; |
| 180 | |
| 181 | if (events == NULL || fd < 0 || events->nb_fd == 0) { |
| 182 | goto error; |
| 183 | } |
| 184 | |
| 185 | ret = epoll_ctl(events->epfd, EPOLL_CTL_DEL, fd, NULL); |
| 186 | if (ret < 0) { |
| 187 | switch (errno) { |
| 188 | case ENOENT: |
| 189 | case EPERM: |
| 190 | /* Print PERROR and goto end not failing. Show must go on. */ |
| 191 | PERROR("epoll_ctl DEL"); |
| 192 | goto end; |
| 193 | default: |
| 194 | PERROR("epoll_ctl DEL fatal"); |
| 195 | goto error; |
| 196 | } |
| 197 | } |
| 198 | |
| 199 | events->nb_fd--; |
| 200 | |
| 201 | end: |
| 202 | return 0; |
| 203 | |
| 204 | error: |
| 205 | return -1; |
| 206 | } |
| 207 | |
| 208 | /* |
| 209 | * Set an fd's events. |
| 210 | */ |
| 211 | LTTNG_HIDDEN |
| 212 | int compat_epoll_mod(struct lttng_poll_event *events, int fd, uint32_t req_events) |
| 213 | { |
| 214 | int ret; |
| 215 | struct epoll_event ev; |
| 216 | |
| 217 | if (events == NULL || fd < 0 || events->nb_fd == 0) { |
| 218 | goto error; |
| 219 | } |
| 220 | |
| 221 | /* |
| 222 | * Zero struct epoll_event to ensure all representations of its |
| 223 | * union are zeroed. |
| 224 | */ |
| 225 | memset(&ev, 0, sizeof(ev)); |
| 226 | ev.events = req_events; |
| 227 | ev.data.fd = fd; |
| 228 | |
| 229 | ret = epoll_ctl(events->epfd, EPOLL_CTL_MOD, fd, &ev); |
| 230 | if (ret < 0) { |
| 231 | switch (errno) { |
| 232 | case ENOENT: |
| 233 | case EPERM: |
| 234 | /* Print PERROR and goto end not failing. Show must go on. */ |
| 235 | PERROR("epoll_ctl MOD"); |
| 236 | goto end; |
| 237 | default: |
| 238 | PERROR("epoll_ctl MOD fatal"); |
| 239 | goto error; |
| 240 | } |
| 241 | } |
| 242 | |
| 243 | end: |
| 244 | return 0; |
| 245 | |
| 246 | error: |
| 247 | return -1; |
| 248 | } |
| 249 | |
| 250 | /* |
| 251 | * Wait on epoll set. This is a blocking call of timeout value. |
| 252 | */ |
| 253 | LTTNG_HIDDEN |
| 254 | int compat_epoll_wait(struct lttng_poll_event *events, int timeout, |
| 255 | bool interruptible) |
| 256 | { |
| 257 | int ret; |
| 258 | uint32_t new_size; |
| 259 | |
| 260 | if (events == NULL || events->events == NULL) { |
| 261 | ERR("Wrong arguments in compat_epoll_wait"); |
| 262 | goto error; |
| 263 | } |
| 264 | |
| 265 | if (events->nb_fd == 0) { |
| 266 | errno = EINVAL; |
| 267 | return -1; |
| 268 | } |
| 269 | |
| 270 | /* |
| 271 | * Resize if needed before waiting. We could either expand the array or |
| 272 | * shrink it down. It's important to note that after this step, we are |
| 273 | * ensured that the events argument of the epoll_wait call will be large |
| 274 | * enough to hold every possible returned events. |
| 275 | */ |
| 276 | new_size = 1U << utils_get_count_order_u32(events->nb_fd); |
| 277 | if (new_size != events->alloc_size && new_size >= events->init_size) { |
| 278 | ret = resize_poll_event(events, new_size); |
| 279 | if (ret < 0) { |
| 280 | /* ENOMEM problem at this point. */ |
| 281 | goto error; |
| 282 | } |
| 283 | } |
| 284 | |
| 285 | do { |
| 286 | ret = epoll_wait(events->epfd, events->events, events->nb_fd, timeout); |
| 287 | } while (!interruptible && ret == -1 && errno == EINTR); |
| 288 | if (ret < 0) { |
| 289 | if (errno != EINTR) { |
| 290 | PERROR("epoll_wait"); |
| 291 | } |
| 292 | goto error; |
| 293 | } |
| 294 | |
| 295 | /* |
| 296 | * Since the returned events are set sequentially in the "events" structure |
| 297 | * we only need to return the epoll_wait value and iterate over it. |
| 298 | */ |
| 299 | return ret; |
| 300 | |
| 301 | error: |
| 302 | return -1; |
| 303 | } |
| 304 | |
| 305 | /* |
| 306 | * Setup poll set maximum size. |
| 307 | */ |
| 308 | LTTNG_HIDDEN |
| 309 | int compat_epoll_set_max_size(void) |
| 310 | { |
| 311 | int ret, fd, retval = 0; |
| 312 | ssize_t size_ret; |
| 313 | char buf[64]; |
| 314 | |
| 315 | fd = open(COMPAT_EPOLL_PROC_PATH, O_RDONLY); |
| 316 | if (fd < 0) { |
| 317 | /* |
| 318 | * Failing on opening [1] is not an error per see. [1] was |
| 319 | * introduced in Linux 2.6.28 but epoll is available since |
| 320 | * 2.5.44. Hence, goto end and set a default value without |
| 321 | * setting an error return value. |
| 322 | * |
| 323 | * [1] /proc/sys/fs/epoll/max_user_watches |
| 324 | */ |
| 325 | retval = 0; |
| 326 | goto end; |
| 327 | } |
| 328 | |
| 329 | size_ret = lttng_read(fd, buf, sizeof(buf)); |
| 330 | /* |
| 331 | * Allow reading a file smaller than buf, but keep space for |
| 332 | * final \0. |
| 333 | */ |
| 334 | if (size_ret < 0 || size_ret >= sizeof(buf)) { |
| 335 | PERROR("read set max size"); |
| 336 | retval = -1; |
| 337 | goto end_read; |
| 338 | } |
| 339 | buf[size_ret] = '\0'; |
| 340 | poll_max_size = atoi(buf); |
| 341 | end_read: |
| 342 | ret = close(fd); |
| 343 | if (ret) { |
| 344 | PERROR("close"); |
| 345 | } |
| 346 | end: |
| 347 | if (!poll_max_size) { |
| 348 | poll_max_size = DEFAULT_POLL_SIZE; |
| 349 | } |
| 350 | DBG("epoll set max size is %d", poll_max_size); |
| 351 | return retval; |
| 352 | } |
| 353 | |
| 354 | #else /* HAVE_EPOLL */ |
| 355 | |
| 356 | #include <sys/resource.h> |
| 357 | #include <sys/time.h> |
| 358 | |
| 359 | /* |
| 360 | * Maximum number of fd we can monitor. |
| 361 | * |
| 362 | * For poll(2), the max fds must not exceed RLIMIT_NOFILE given by |
| 363 | * getrlimit(2). |
| 364 | */ |
| 365 | static unsigned int poll_max_size; |
| 366 | |
| 367 | /* |
| 368 | * Resize the epoll events structure of the new size. |
| 369 | * |
| 370 | * Return 0 on success or else -1 with the current events pointer untouched. |
| 371 | */ |
| 372 | static int resize_poll_event(struct compat_poll_event_array *array, |
| 373 | uint32_t new_size) |
| 374 | { |
| 375 | struct pollfd *ptr; |
| 376 | |
| 377 | assert(array); |
| 378 | |
| 379 | /* Refuse to resize the array more than the max size. */ |
| 380 | if (new_size > poll_max_size) { |
| 381 | goto error; |
| 382 | } |
| 383 | |
| 384 | ptr = realloc(array->events, new_size * sizeof(*ptr)); |
| 385 | if (ptr == NULL) { |
| 386 | PERROR("realloc epoll add"); |
| 387 | goto error; |
| 388 | } |
| 389 | if (new_size > array->alloc_size) { |
| 390 | /* Zero newly allocated memory */ |
| 391 | memset(ptr + array->alloc_size, 0, |
| 392 | (new_size - array->alloc_size) * sizeof(*ptr)); |
| 393 | } |
| 394 | array->events = ptr; |
| 395 | array->alloc_size = new_size; |
| 396 | |
| 397 | return 0; |
| 398 | |
| 399 | error: |
| 400 | return -1; |
| 401 | } |
| 402 | |
| 403 | /* |
| 404 | * Update events with the current events object. |
| 405 | */ |
| 406 | static int update_current_events(struct lttng_poll_event *events) |
| 407 | { |
| 408 | int ret; |
| 409 | struct compat_poll_event_array *current, *wait; |
| 410 | |
| 411 | assert(events); |
| 412 | |
| 413 | current = &events->current; |
| 414 | wait = &events->wait; |
| 415 | |
| 416 | wait->nb_fd = current->nb_fd; |
| 417 | if (current->alloc_size != wait->alloc_size) { |
| 418 | ret = resize_poll_event(wait, current->alloc_size); |
| 419 | if (ret < 0) { |
| 420 | goto error; |
| 421 | } |
| 422 | } |
| 423 | memcpy(wait->events, current->events, |
| 424 | current->nb_fd * sizeof(*current->events)); |
| 425 | |
| 426 | /* Update is done. */ |
| 427 | events->need_update = 0; |
| 428 | |
| 429 | return 0; |
| 430 | |
| 431 | error: |
| 432 | return -1; |
| 433 | } |
| 434 | |
| 435 | /* |
| 436 | * Create pollfd data structure. |
| 437 | */ |
| 438 | LTTNG_HIDDEN |
| 439 | int compat_poll_create(struct lttng_poll_event *events, int size) |
| 440 | { |
| 441 | struct compat_poll_event_array *current, *wait; |
| 442 | |
| 443 | if (events == NULL || size <= 0) { |
| 444 | ERR("Wrong arguments for poll create"); |
| 445 | goto error; |
| 446 | } |
| 447 | |
| 448 | if (!poll_max_size) { |
| 449 | if (lttng_poll_set_max_size()) { |
| 450 | goto error; |
| 451 | } |
| 452 | } |
| 453 | |
| 454 | /* Don't bust the limit here */ |
| 455 | if (size > poll_max_size) { |
| 456 | size = poll_max_size; |
| 457 | } |
| 458 | |
| 459 | /* Reset everything before begining the allocation. */ |
| 460 | memset(events, 0, sizeof(struct lttng_poll_event)); |
| 461 | |
| 462 | current = &events->current; |
| 463 | wait = &events->wait; |
| 464 | |
| 465 | /* This *must* be freed by using lttng_poll_free() */ |
| 466 | wait->events = zmalloc(size * sizeof(struct pollfd)); |
| 467 | if (wait->events == NULL) { |
| 468 | PERROR("zmalloc struct pollfd"); |
| 469 | goto error; |
| 470 | } |
| 471 | |
| 472 | wait->alloc_size = wait->init_size = size; |
| 473 | |
| 474 | current->events = zmalloc(size * sizeof(struct pollfd)); |
| 475 | if (current->events == NULL) { |
| 476 | PERROR("zmalloc struct current pollfd"); |
| 477 | goto error; |
| 478 | } |
| 479 | |
| 480 | current->alloc_size = current->init_size = size; |
| 481 | |
| 482 | return 0; |
| 483 | |
| 484 | error: |
| 485 | return -1; |
| 486 | } |
| 487 | |
| 488 | /* |
| 489 | * Add fd to pollfd data structure with requested events. |
| 490 | */ |
| 491 | LTTNG_HIDDEN |
| 492 | int compat_poll_add(struct lttng_poll_event *events, int fd, |
| 493 | uint32_t req_events) |
| 494 | { |
| 495 | int new_size, ret, i; |
| 496 | struct compat_poll_event_array *current; |
| 497 | |
| 498 | if (events == NULL || events->current.events == NULL || fd < 0) { |
| 499 | ERR("Bad compat poll add arguments"); |
| 500 | goto error; |
| 501 | } |
| 502 | |
| 503 | current = &events->current; |
| 504 | |
| 505 | /* Check if fd we are trying to add is already there. */ |
| 506 | for (i = 0; i < current->nb_fd; i++) { |
| 507 | if (current->events[i].fd == fd) { |
| 508 | errno = EEXIST; |
| 509 | goto error; |
| 510 | } |
| 511 | } |
| 512 | |
| 513 | /* Resize array if needed. */ |
| 514 | new_size = 1U << utils_get_count_order_u32(current->nb_fd + 1); |
| 515 | if (new_size != current->alloc_size && new_size >= current->init_size) { |
| 516 | ret = resize_poll_event(current, new_size); |
| 517 | if (ret < 0) { |
| 518 | goto error; |
| 519 | } |
| 520 | } |
| 521 | |
| 522 | current->events[current->nb_fd].fd = fd; |
| 523 | current->events[current->nb_fd].events = req_events; |
| 524 | current->nb_fd++; |
| 525 | events->need_update = 1; |
| 526 | |
| 527 | DBG("fd %d of %d added to pollfd", fd, current->nb_fd); |
| 528 | |
| 529 | return 0; |
| 530 | |
| 531 | error: |
| 532 | return -1; |
| 533 | } |
| 534 | |
| 535 | /* |
| 536 | * Modify an fd's events.. |
| 537 | */ |
| 538 | LTTNG_HIDDEN |
| 539 | int compat_poll_mod(struct lttng_poll_event *events, int fd, |
| 540 | uint32_t req_events) |
| 541 | { |
| 542 | int i; |
| 543 | struct compat_poll_event_array *current; |
| 544 | |
| 545 | if (events == NULL || events->current.nb_fd == 0 || |
| 546 | events->current.events == NULL || fd < 0) { |
| 547 | ERR("Bad compat poll mod arguments"); |
| 548 | goto error; |
| 549 | } |
| 550 | |
| 551 | current = &events->current; |
| 552 | |
| 553 | for (i = 0; i < current->nb_fd; i++) { |
| 554 | if (current->events[i].fd == fd) { |
| 555 | current->events[i].events = req_events; |
| 556 | events->need_update = 1; |
| 557 | break; |
| 558 | } |
| 559 | } |
| 560 | |
| 561 | /* |
| 562 | * The epoll flavor doesn't flag modifying a non-included FD as an |
| 563 | * error. |
| 564 | */ |
| 565 | |
| 566 | return 0; |
| 567 | |
| 568 | error: |
| 569 | return -1; |
| 570 | } |
| 571 | |
| 572 | /* |
| 573 | * Remove a fd from the pollfd structure. |
| 574 | */ |
| 575 | LTTNG_HIDDEN |
| 576 | int compat_poll_del(struct lttng_poll_event *events, int fd) |
| 577 | { |
| 578 | int i, count = 0, ret; |
| 579 | uint32_t new_size; |
| 580 | struct compat_poll_event_array *current; |
| 581 | |
| 582 | if (events == NULL || events->current.nb_fd == 0 || |
| 583 | events->current.events == NULL || fd < 0) { |
| 584 | goto error; |
| 585 | } |
| 586 | |
| 587 | /* Ease our life a bit. */ |
| 588 | current = &events->current; |
| 589 | |
| 590 | for (i = 0; i < current->nb_fd; i++) { |
| 591 | /* Don't put back the fd we want to delete */ |
| 592 | if (current->events[i].fd != fd) { |
| 593 | current->events[count].fd = current->events[i].fd; |
| 594 | current->events[count].events = current->events[i].events; |
| 595 | count++; |
| 596 | } |
| 597 | } |
| 598 | |
| 599 | /* The fd was not in our set, return no error as with epoll. */ |
| 600 | if (current->nb_fd == count) { |
| 601 | goto end; |
| 602 | } |
| 603 | |
| 604 | /* No fd duplicate should be ever added into array. */ |
| 605 | assert(current->nb_fd - 1 == count); |
| 606 | current->nb_fd = count; |
| 607 | |
| 608 | /* Resize array if needed. */ |
| 609 | new_size = 1U << utils_get_count_order_u32(current->nb_fd); |
| 610 | if (new_size != current->alloc_size && new_size >= current->init_size |
| 611 | && current->nb_fd != 0) { |
| 612 | ret = resize_poll_event(current, new_size); |
| 613 | if (ret < 0) { |
| 614 | goto error; |
| 615 | } |
| 616 | } |
| 617 | |
| 618 | events->need_update = 1; |
| 619 | |
| 620 | end: |
| 621 | return 0; |
| 622 | |
| 623 | error: |
| 624 | return -1; |
| 625 | } |
| 626 | |
| 627 | /* |
| 628 | * Wait on poll() with timeout. Blocking call. |
| 629 | */ |
| 630 | LTTNG_HIDDEN |
| 631 | int compat_poll_wait(struct lttng_poll_event *events, int timeout, |
| 632 | bool interruptible) |
| 633 | { |
| 634 | int ret, active_fd_count; |
| 635 | size_t pos = 0, consecutive_entries = 0, non_idle_pos; |
| 636 | |
| 637 | if (events == NULL || events->current.events == NULL) { |
| 638 | ERR("poll wait arguments error"); |
| 639 | goto error; |
| 640 | } |
| 641 | |
| 642 | if (events->current.nb_fd == 0) { |
| 643 | /* Return an invalid error to be consistent with epoll. */ |
| 644 | errno = EINVAL; |
| 645 | events->wait.nb_fd = 0; |
| 646 | goto error; |
| 647 | } |
| 648 | |
| 649 | if (events->need_update) { |
| 650 | ret = update_current_events(events); |
| 651 | if (ret < 0) { |
| 652 | errno = ENOMEM; |
| 653 | goto error; |
| 654 | } |
| 655 | } |
| 656 | |
| 657 | do { |
| 658 | ret = poll(events->wait.events, events->wait.nb_fd, timeout); |
| 659 | } while (!interruptible && ret == -1 && errno == EINTR); |
| 660 | if (ret < 0) { |
| 661 | if (errno != EINTR) { |
| 662 | PERROR("poll wait"); |
| 663 | } |
| 664 | goto error; |
| 665 | } |
| 666 | |
| 667 | active_fd_count = ret; |
| 668 | |
| 669 | /* |
| 670 | * Move all active pollfd structs to the beginning of the |
| 671 | * array to emulate compat-epoll behaviour. |
| 672 | */ |
| 673 | if (active_fd_count == events->wait.nb_fd) { |
| 674 | goto end; |
| 675 | } |
| 676 | |
| 677 | while (consecutive_entries != active_fd_count) { |
| 678 | struct pollfd *current = &events->wait.events[pos]; |
| 679 | struct pollfd idle_entry; |
| 680 | |
| 681 | if (current->revents != 0) { |
| 682 | consecutive_entries++; |
| 683 | pos++; |
| 684 | continue; |
| 685 | } |
| 686 | |
| 687 | non_idle_pos = pos; |
| 688 | |
| 689 | /* Look for next non-idle entry. */ |
| 690 | while (events->wait.events[++non_idle_pos].revents == 0); |
| 691 | |
| 692 | /* Swap idle and non-idle entries. */ |
| 693 | idle_entry = *current; |
| 694 | *current = events->wait.events[non_idle_pos]; |
| 695 | events->wait.events[non_idle_pos] = idle_entry; |
| 696 | |
| 697 | consecutive_entries++; |
| 698 | pos++; |
| 699 | } |
| 700 | end: |
| 701 | return ret; |
| 702 | |
| 703 | error: |
| 704 | return -1; |
| 705 | } |
| 706 | |
| 707 | /* |
| 708 | * Setup poll set maximum size. |
| 709 | */ |
| 710 | LTTNG_HIDDEN |
| 711 | int compat_poll_set_max_size(void) |
| 712 | { |
| 713 | int ret, retval = 0; |
| 714 | struct rlimit lim; |
| 715 | |
| 716 | ret = getrlimit(RLIMIT_NOFILE, &lim); |
| 717 | if (ret < 0) { |
| 718 | PERROR("getrlimit poll RLIMIT_NOFILE"); |
| 719 | retval = -1; |
| 720 | goto end; |
| 721 | } |
| 722 | |
| 723 | poll_max_size = lim.rlim_cur; |
| 724 | end: |
| 725 | if (poll_max_size == 0) { |
| 726 | poll_max_size = DEFAULT_POLL_SIZE; |
| 727 | } |
| 728 | DBG("poll set max size set to %u", poll_max_size); |
| 729 | return retval; |
| 730 | } |
| 731 | |
| 732 | #endif /* !HAVE_EPOLL */ |