| 1 | /* |
| 2 | * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca> |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or |
| 5 | * modify it under the terms of the GNU General Public License |
| 6 | * as published by the Free Software Foundation; only version 2 |
| 7 | * of the License. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | * GNU General Public License for more details. |
| 13 | * |
| 14 | * You should have received a copy of the GNU General Public License |
| 15 | * along with this program; if not, write to the Free Software |
| 16 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 17 | */ |
| 18 | |
| 19 | #define _GNU_SOURCE |
| 20 | #include <errno.h> |
| 21 | #include <fcntl.h> |
| 22 | #include <stdlib.h> |
| 23 | #include <stdio.h> |
| 24 | #include <string.h> |
| 25 | #include <unistd.h> |
| 26 | |
| 27 | #include <common/common.h> |
| 28 | #include <common/kernel-ctl/kernel-ctl.h> |
| 29 | |
| 30 | #include "kernel.h" |
| 31 | #include "kern-modules.h" |
| 32 | |
| 33 | /* |
| 34 | * Add context on a kernel channel. |
| 35 | */ |
| 36 | int kernel_add_channel_context(struct ltt_kernel_channel *chan, |
| 37 | struct lttng_kernel_context *ctx) |
| 38 | { |
| 39 | int ret; |
| 40 | |
| 41 | DBG("Adding context to channel %s", chan->channel->name); |
| 42 | ret = kernctl_add_context(chan->fd, ctx); |
| 43 | if (ret < 0) { |
| 44 | if (errno != EEXIST) { |
| 45 | PERROR("add context ioctl"); |
| 46 | } else { |
| 47 | /* If EEXIST, we just ignore the error */ |
| 48 | ret = 0; |
| 49 | } |
| 50 | goto error; |
| 51 | } |
| 52 | |
| 53 | chan->ctx = zmalloc(sizeof(struct lttng_kernel_context)); |
| 54 | if (chan->ctx == NULL) { |
| 55 | PERROR("zmalloc event context"); |
| 56 | goto error; |
| 57 | } |
| 58 | |
| 59 | memcpy(chan->ctx, ctx, sizeof(struct lttng_kernel_context)); |
| 60 | |
| 61 | return 0; |
| 62 | |
| 63 | error: |
| 64 | return ret; |
| 65 | } |
| 66 | |
| 67 | /* |
| 68 | * Add context on a kernel event. |
| 69 | */ |
| 70 | int kernel_add_event_context(struct ltt_kernel_event *event, |
| 71 | struct lttng_kernel_context *ctx) |
| 72 | { |
| 73 | int ret; |
| 74 | |
| 75 | DBG("Adding context to event %s", event->event->name); |
| 76 | ret = kernctl_add_context(event->fd, ctx); |
| 77 | if (ret < 0) { |
| 78 | PERROR("add context ioctl"); |
| 79 | goto error; |
| 80 | } |
| 81 | |
| 82 | event->ctx = zmalloc(sizeof(struct lttng_kernel_context)); |
| 83 | if (event->ctx == NULL) { |
| 84 | PERROR("zmalloc event context"); |
| 85 | goto error; |
| 86 | } |
| 87 | |
| 88 | memcpy(event->ctx, ctx, sizeof(struct lttng_kernel_context)); |
| 89 | |
| 90 | return 0; |
| 91 | |
| 92 | error: |
| 93 | return ret; |
| 94 | } |
| 95 | |
| 96 | /* |
| 97 | * Create a new kernel session, register it to the kernel tracer and add it to |
| 98 | * the session daemon session. |
| 99 | */ |
| 100 | int kernel_create_session(struct ltt_session *session, int tracer_fd) |
| 101 | { |
| 102 | int ret; |
| 103 | struct ltt_kernel_session *lks; |
| 104 | |
| 105 | /* Allocate data structure */ |
| 106 | lks = trace_kernel_create_session(session->path); |
| 107 | if (lks == NULL) { |
| 108 | ret = -1; |
| 109 | goto error; |
| 110 | } |
| 111 | |
| 112 | /* Kernel tracer session creation */ |
| 113 | ret = kernctl_create_session(tracer_fd); |
| 114 | if (ret < 0) { |
| 115 | PERROR("ioctl kernel create session"); |
| 116 | goto error; |
| 117 | } |
| 118 | |
| 119 | lks->fd = ret; |
| 120 | /* Prevent fd duplication after execlp() */ |
| 121 | ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC); |
| 122 | if (ret < 0) { |
| 123 | PERROR("fcntl session fd"); |
| 124 | } |
| 125 | |
| 126 | lks->consumer_fds_sent = 0; |
| 127 | session->kernel_session = lks; |
| 128 | |
| 129 | DBG("Kernel session created (fd: %d)", lks->fd); |
| 130 | |
| 131 | return 0; |
| 132 | |
| 133 | error: |
| 134 | return ret; |
| 135 | } |
| 136 | |
| 137 | /* |
| 138 | * Create a kernel channel, register it to the kernel tracer and add it to the |
| 139 | * kernel session. |
| 140 | */ |
| 141 | int kernel_create_channel(struct ltt_kernel_session *session, |
| 142 | struct lttng_channel *chan, char *path) |
| 143 | { |
| 144 | int ret; |
| 145 | struct ltt_kernel_channel *lkc; |
| 146 | |
| 147 | /* Allocate kernel channel */ |
| 148 | lkc = trace_kernel_create_channel(chan, path); |
| 149 | if (lkc == NULL) { |
| 150 | goto error; |
| 151 | } |
| 152 | |
| 153 | /* Kernel tracer channel creation */ |
| 154 | ret = kernctl_create_channel(session->fd, &lkc->channel->attr); |
| 155 | if (ret < 0) { |
| 156 | PERROR("ioctl kernel create channel"); |
| 157 | goto error; |
| 158 | } |
| 159 | |
| 160 | /* Setup the channel fd */ |
| 161 | lkc->fd = ret; |
| 162 | /* Prevent fd duplication after execlp() */ |
| 163 | ret = fcntl(lkc->fd, F_SETFD, FD_CLOEXEC); |
| 164 | if (ret < 0) { |
| 165 | PERROR("fcntl session fd"); |
| 166 | } |
| 167 | |
| 168 | /* Add channel to session */ |
| 169 | cds_list_add(&lkc->list, &session->channel_list.head); |
| 170 | session->channel_count++; |
| 171 | |
| 172 | DBG("Kernel channel %s created (fd: %d and path: %s)", |
| 173 | lkc->channel->name, lkc->fd, lkc->pathname); |
| 174 | |
| 175 | return 0; |
| 176 | |
| 177 | error: |
| 178 | return -1; |
| 179 | } |
| 180 | |
| 181 | /* |
| 182 | * Create a kernel event, enable it to the kernel tracer and add it to the |
| 183 | * channel event list of the kernel session. |
| 184 | */ |
| 185 | int kernel_create_event(struct lttng_event *ev, |
| 186 | struct ltt_kernel_channel *channel) |
| 187 | { |
| 188 | int ret; |
| 189 | struct ltt_kernel_event *event; |
| 190 | |
| 191 | event = trace_kernel_create_event(ev); |
| 192 | if (event == NULL) { |
| 193 | ret = -1; |
| 194 | goto error; |
| 195 | } |
| 196 | |
| 197 | ret = kernctl_create_event(channel->fd, event->event); |
| 198 | if (ret < 0) { |
| 199 | if (errno != EEXIST) { |
| 200 | PERROR("create event ioctl"); |
| 201 | } |
| 202 | ret = -errno; |
| 203 | goto free_event; |
| 204 | } |
| 205 | |
| 206 | /* |
| 207 | * LTTNG_KERNEL_SYSCALL event creation will return 0 on success. |
| 208 | */ |
| 209 | if (ret == 0 && event->event->instrumentation == LTTNG_KERNEL_SYSCALL) { |
| 210 | DBG2("Kernel event syscall creation success"); |
| 211 | /* |
| 212 | * We use fd == -1 to ensure that we never trigger a close of fd |
| 213 | * 0. |
| 214 | */ |
| 215 | event->fd = -1; |
| 216 | goto add_list; |
| 217 | } |
| 218 | |
| 219 | event->fd = ret; |
| 220 | /* Prevent fd duplication after execlp() */ |
| 221 | ret = fcntl(event->fd, F_SETFD, FD_CLOEXEC); |
| 222 | if (ret < 0) { |
| 223 | PERROR("fcntl session fd"); |
| 224 | } |
| 225 | |
| 226 | add_list: |
| 227 | /* Add event to event list */ |
| 228 | cds_list_add(&event->list, &channel->events_list.head); |
| 229 | channel->event_count++; |
| 230 | |
| 231 | DBG("Event %s created (fd: %d)", ev->name, event->fd); |
| 232 | |
| 233 | return 0; |
| 234 | |
| 235 | free_event: |
| 236 | free(event); |
| 237 | error: |
| 238 | return ret; |
| 239 | } |
| 240 | |
| 241 | /* |
| 242 | * Disable a kernel channel. |
| 243 | */ |
| 244 | int kernel_disable_channel(struct ltt_kernel_channel *chan) |
| 245 | { |
| 246 | int ret; |
| 247 | |
| 248 | ret = kernctl_disable(chan->fd); |
| 249 | if (ret < 0) { |
| 250 | PERROR("disable chan ioctl"); |
| 251 | ret = errno; |
| 252 | goto error; |
| 253 | } |
| 254 | |
| 255 | chan->enabled = 0; |
| 256 | DBG("Kernel channel %s disabled (fd: %d)", chan->channel->name, chan->fd); |
| 257 | |
| 258 | return 0; |
| 259 | |
| 260 | error: |
| 261 | return ret; |
| 262 | } |
| 263 | |
| 264 | /* |
| 265 | * Enable a kernel channel. |
| 266 | */ |
| 267 | int kernel_enable_channel(struct ltt_kernel_channel *chan) |
| 268 | { |
| 269 | int ret; |
| 270 | |
| 271 | ret = kernctl_enable(chan->fd); |
| 272 | if (ret < 0 && errno != EEXIST) { |
| 273 | PERROR("Enable kernel chan"); |
| 274 | goto error; |
| 275 | } |
| 276 | |
| 277 | chan->enabled = 1; |
| 278 | DBG("Kernel channel %s enabled (fd: %d)", chan->channel->name, chan->fd); |
| 279 | |
| 280 | return 0; |
| 281 | |
| 282 | error: |
| 283 | return ret; |
| 284 | } |
| 285 | |
| 286 | /* |
| 287 | * Enable a kernel event. |
| 288 | */ |
| 289 | int kernel_enable_event(struct ltt_kernel_event *event) |
| 290 | { |
| 291 | int ret; |
| 292 | |
| 293 | ret = kernctl_enable(event->fd); |
| 294 | if (ret < 0 && errno != EEXIST) { |
| 295 | PERROR("enable kernel event"); |
| 296 | goto error; |
| 297 | } |
| 298 | |
| 299 | event->enabled = 1; |
| 300 | DBG("Kernel event %s enabled (fd: %d)", event->event->name, event->fd); |
| 301 | |
| 302 | return 0; |
| 303 | |
| 304 | error: |
| 305 | return ret; |
| 306 | } |
| 307 | |
| 308 | /* |
| 309 | * Disable a kernel event. |
| 310 | */ |
| 311 | int kernel_disable_event(struct ltt_kernel_event *event) |
| 312 | { |
| 313 | int ret; |
| 314 | |
| 315 | ret = kernctl_disable(event->fd); |
| 316 | if (ret < 0 && errno != EEXIST) { |
| 317 | PERROR("disable kernel event"); |
| 318 | goto error; |
| 319 | } |
| 320 | |
| 321 | event->enabled = 0; |
| 322 | DBG("Kernel event %s disabled (fd: %d)", event->event->name, event->fd); |
| 323 | |
| 324 | return 0; |
| 325 | |
| 326 | error: |
| 327 | return ret; |
| 328 | } |
| 329 | |
| 330 | /* |
| 331 | * Create kernel metadata, open from the kernel tracer and add it to the |
| 332 | * kernel session. |
| 333 | */ |
| 334 | int kernel_open_metadata(struct ltt_kernel_session *session, char *path) |
| 335 | { |
| 336 | int ret; |
| 337 | struct ltt_kernel_metadata *lkm; |
| 338 | |
| 339 | /* Allocate kernel metadata */ |
| 340 | lkm = trace_kernel_create_metadata(path); |
| 341 | if (lkm == NULL) { |
| 342 | goto error; |
| 343 | } |
| 344 | |
| 345 | /* Kernel tracer metadata creation */ |
| 346 | ret = kernctl_open_metadata(session->fd, &lkm->conf->attr); |
| 347 | if (ret < 0) { |
| 348 | goto error; |
| 349 | } |
| 350 | |
| 351 | lkm->fd = ret; |
| 352 | /* Prevent fd duplication after execlp() */ |
| 353 | ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC); |
| 354 | if (ret < 0) { |
| 355 | PERROR("fcntl session fd"); |
| 356 | } |
| 357 | |
| 358 | session->metadata = lkm; |
| 359 | |
| 360 | DBG("Kernel metadata opened (fd: %d and path: %s)", lkm->fd, lkm->pathname); |
| 361 | |
| 362 | return 0; |
| 363 | |
| 364 | error: |
| 365 | return -1; |
| 366 | } |
| 367 | |
| 368 | /* |
| 369 | * Start tracing session. |
| 370 | */ |
| 371 | int kernel_start_session(struct ltt_kernel_session *session) |
| 372 | { |
| 373 | int ret; |
| 374 | |
| 375 | ret = kernctl_start_session(session->fd); |
| 376 | if (ret < 0) { |
| 377 | PERROR("ioctl start session"); |
| 378 | goto error; |
| 379 | } |
| 380 | |
| 381 | DBG("Kernel session started"); |
| 382 | |
| 383 | return 0; |
| 384 | |
| 385 | error: |
| 386 | return ret; |
| 387 | } |
| 388 | |
| 389 | /* |
| 390 | * Make a kernel wait to make sure in-flight probe have completed. |
| 391 | */ |
| 392 | void kernel_wait_quiescent(int fd) |
| 393 | { |
| 394 | int ret; |
| 395 | |
| 396 | DBG("Kernel quiescent wait on %d", fd); |
| 397 | |
| 398 | ret = kernctl_wait_quiescent(fd); |
| 399 | if (ret < 0) { |
| 400 | PERROR("wait quiescent ioctl"); |
| 401 | ERR("Kernel quiescent wait failed"); |
| 402 | } |
| 403 | } |
| 404 | |
| 405 | /* |
| 406 | * Kernel calibrate |
| 407 | */ |
| 408 | int kernel_calibrate(int fd, struct lttng_kernel_calibrate *calibrate) |
| 409 | { |
| 410 | int ret; |
| 411 | |
| 412 | ret = kernctl_calibrate(fd, calibrate); |
| 413 | if (ret < 0) { |
| 414 | PERROR("calibrate ioctl"); |
| 415 | return -1; |
| 416 | } |
| 417 | |
| 418 | return 0; |
| 419 | } |
| 420 | |
| 421 | |
| 422 | /* |
| 423 | * Force flush buffer of metadata. |
| 424 | */ |
| 425 | int kernel_metadata_flush_buffer(int fd) |
| 426 | { |
| 427 | int ret; |
| 428 | |
| 429 | ret = kernctl_buffer_flush(fd); |
| 430 | if (ret < 0) { |
| 431 | ERR("Fail to flush metadata buffers %d (ret: %d", fd, ret); |
| 432 | } |
| 433 | |
| 434 | return 0; |
| 435 | } |
| 436 | |
| 437 | /* |
| 438 | * Force flush buffer for channel. |
| 439 | */ |
| 440 | int kernel_flush_buffer(struct ltt_kernel_channel *channel) |
| 441 | { |
| 442 | int ret; |
| 443 | struct ltt_kernel_stream *stream; |
| 444 | |
| 445 | DBG("Flush buffer for channel %s", channel->channel->name); |
| 446 | |
| 447 | cds_list_for_each_entry(stream, &channel->stream_list.head, list) { |
| 448 | DBG("Flushing channel stream %d", stream->fd); |
| 449 | ret = kernctl_buffer_flush(stream->fd); |
| 450 | if (ret < 0) { |
| 451 | PERROR("ioctl"); |
| 452 | ERR("Fail to flush buffer for stream %d (ret: %d)", |
| 453 | stream->fd, ret); |
| 454 | } |
| 455 | } |
| 456 | |
| 457 | return 0; |
| 458 | } |
| 459 | |
| 460 | /* |
| 461 | * Stop tracing session. |
| 462 | */ |
| 463 | int kernel_stop_session(struct ltt_kernel_session *session) |
| 464 | { |
| 465 | int ret; |
| 466 | |
| 467 | ret = kernctl_stop_session(session->fd); |
| 468 | if (ret < 0) { |
| 469 | goto error; |
| 470 | } |
| 471 | |
| 472 | DBG("Kernel session stopped"); |
| 473 | |
| 474 | return 0; |
| 475 | |
| 476 | error: |
| 477 | return ret; |
| 478 | } |
| 479 | |
| 480 | /* |
| 481 | * Open stream of channel, register it to the kernel tracer and add it |
| 482 | * to the stream list of the channel. |
| 483 | * |
| 484 | * Return the number of created stream. Else, a negative value. |
| 485 | */ |
| 486 | int kernel_open_channel_stream(struct ltt_kernel_channel *channel) |
| 487 | { |
| 488 | int ret; |
| 489 | struct ltt_kernel_stream *lks; |
| 490 | |
| 491 | while ((ret = kernctl_create_stream(channel->fd)) >= 0) { |
| 492 | lks = trace_kernel_create_stream(); |
| 493 | if (lks == NULL) { |
| 494 | ret = close(ret); |
| 495 | if (ret) { |
| 496 | PERROR("close"); |
| 497 | } |
| 498 | goto error; |
| 499 | } |
| 500 | |
| 501 | lks->fd = ret; |
| 502 | /* Prevent fd duplication after execlp() */ |
| 503 | ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC); |
| 504 | if (ret < 0) { |
| 505 | PERROR("fcntl session fd"); |
| 506 | } |
| 507 | |
| 508 | ret = asprintf(&lks->pathname, "%s/%s_%d", |
| 509 | channel->pathname, channel->channel->name, channel->stream_count); |
| 510 | if (ret < 0) { |
| 511 | PERROR("asprintf kernel create stream"); |
| 512 | goto error; |
| 513 | } |
| 514 | |
| 515 | /* Add stream to channe stream list */ |
| 516 | cds_list_add(&lks->list, &channel->stream_list.head); |
| 517 | channel->stream_count++; |
| 518 | |
| 519 | DBG("Kernel stream %d created (fd: %d, state: %d, path: %s)", |
| 520 | channel->stream_count, lks->fd, lks->state, lks->pathname); |
| 521 | } |
| 522 | |
| 523 | return channel->stream_count; |
| 524 | |
| 525 | error: |
| 526 | return -1; |
| 527 | } |
| 528 | |
| 529 | /* |
| 530 | * Open the metadata stream and set it to the kernel session. |
| 531 | */ |
| 532 | int kernel_open_metadata_stream(struct ltt_kernel_session *session) |
| 533 | { |
| 534 | int ret; |
| 535 | |
| 536 | ret = kernctl_create_stream(session->metadata->fd); |
| 537 | if (ret < 0) { |
| 538 | PERROR("kernel create metadata stream"); |
| 539 | goto error; |
| 540 | } |
| 541 | |
| 542 | DBG("Kernel metadata stream created (fd: %d)", ret); |
| 543 | session->metadata_stream_fd = ret; |
| 544 | /* Prevent fd duplication after execlp() */ |
| 545 | ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC); |
| 546 | if (ret < 0) { |
| 547 | PERROR("fcntl session fd"); |
| 548 | } |
| 549 | |
| 550 | return 0; |
| 551 | |
| 552 | error: |
| 553 | return -1; |
| 554 | } |
| 555 | |
| 556 | /* |
| 557 | * Get the event list from the kernel tracer and return the number of elements. |
| 558 | */ |
| 559 | ssize_t kernel_list_events(int tracer_fd, struct lttng_event **events) |
| 560 | { |
| 561 | int fd, pos, ret; |
| 562 | char *event; |
| 563 | size_t nbmem, count = 0; |
| 564 | ssize_t size; |
| 565 | FILE *fp; |
| 566 | struct lttng_event *elist; |
| 567 | |
| 568 | fd = kernctl_tracepoint_list(tracer_fd); |
| 569 | if (fd < 0) { |
| 570 | PERROR("kernel tracepoint list"); |
| 571 | goto error; |
| 572 | } |
| 573 | |
| 574 | fp = fdopen(fd, "r"); |
| 575 | if (fp == NULL) { |
| 576 | PERROR("kernel tracepoint list fdopen"); |
| 577 | goto error_fp; |
| 578 | } |
| 579 | |
| 580 | /* |
| 581 | * Init memory size counter |
| 582 | * See kernel-ctl.h for explanation of this value |
| 583 | */ |
| 584 | nbmem = KERNEL_EVENT_INIT_LIST_SIZE; |
| 585 | elist = zmalloc(sizeof(struct lttng_event) * nbmem); |
| 586 | |
| 587 | while ((size = fscanf(fp, "event { name = %m[^;]; };%n\n", &event, &pos)) == 1) { |
| 588 | if (count >= nbmem) { |
| 589 | DBG("Reallocating event list from %zu to %zu bytes", nbmem, |
| 590 | nbmem * 2); |
| 591 | /* Double the size */ |
| 592 | nbmem <<= 1; |
| 593 | elist = realloc(elist, nbmem * sizeof(struct lttng_event)); |
| 594 | if (elist == NULL) { |
| 595 | PERROR("realloc list events"); |
| 596 | count = -ENOMEM; |
| 597 | goto end; |
| 598 | } |
| 599 | } |
| 600 | strncpy(elist[count].name, event, LTTNG_SYMBOL_NAME_LEN); |
| 601 | elist[count].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0'; |
| 602 | elist[count].enabled = -1; |
| 603 | count++; |
| 604 | } |
| 605 | |
| 606 | *events = elist; |
| 607 | DBG("Kernel list events done (%zu events)", count); |
| 608 | end: |
| 609 | ret = fclose(fp); /* closes both fp and fd */ |
| 610 | if (ret) { |
| 611 | PERROR("fclose"); |
| 612 | } |
| 613 | return count; |
| 614 | |
| 615 | error_fp: |
| 616 | ret = close(fd); |
| 617 | if (ret) { |
| 618 | PERROR("close"); |
| 619 | } |
| 620 | error: |
| 621 | return -1; |
| 622 | } |
| 623 | |
| 624 | /* |
| 625 | * Get kernel version and validate it. |
| 626 | */ |
| 627 | int kernel_validate_version(int tracer_fd) |
| 628 | { |
| 629 | int ret; |
| 630 | struct lttng_kernel_tracer_version version; |
| 631 | |
| 632 | ret = kernctl_tracer_version(tracer_fd, &version); |
| 633 | if (ret < 0) { |
| 634 | ERR("Failed at getting the lttng-modules version"); |
| 635 | goto error; |
| 636 | } |
| 637 | |
| 638 | /* Validate version */ |
| 639 | if (version.major != KERN_MODULES_PRE_MAJOR |
| 640 | && version.major != KERN_MODULES_MAJOR) { |
| 641 | goto error_version; |
| 642 | } |
| 643 | |
| 644 | DBG2("Kernel tracer version validated (major version %d)", version.major); |
| 645 | return 0; |
| 646 | |
| 647 | error_version: |
| 648 | ERR("Kernel major version %d is not compatible (supporting <= %d)", |
| 649 | version.major, KERN_MODULES_MAJOR) |
| 650 | ret = -1; |
| 651 | |
| 652 | error: |
| 653 | return ret; |
| 654 | } |
| 655 | |
| 656 | /* |
| 657 | * Kernel work-arounds called at the start of sessiond main(). |
| 658 | */ |
| 659 | int init_kernel_workarounds(void) |
| 660 | { |
| 661 | int ret; |
| 662 | FILE *fp; |
| 663 | |
| 664 | /* |
| 665 | * boot_id needs to be read once before being used concurrently |
| 666 | * to deal with a Linux kernel race. A fix is proposed for |
| 667 | * upstream, but the work-around is needed for older kernels. |
| 668 | */ |
| 669 | fp = fopen("/proc/sys/kernel/random/boot_id", "r"); |
| 670 | if (!fp) { |
| 671 | goto end_boot_id; |
| 672 | } |
| 673 | while (!feof(fp)) { |
| 674 | char buf[37] = ""; |
| 675 | |
| 676 | ret = fread(buf, 1, sizeof(buf), fp); |
| 677 | if (ret < 0) { |
| 678 | /* Ignore error, we don't really care */ |
| 679 | } |
| 680 | } |
| 681 | ret = fclose(fp); |
| 682 | if (ret) { |
| 683 | PERROR("fclose"); |
| 684 | } |
| 685 | end_boot_id: |
| 686 | return 0; |
| 687 | } |