| 1 | /* |
| 2 | * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca> |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License, version 2 only, |
| 6 | * as published by the Free Software Foundation. |
| 7 | * |
| 8 | * This program is distributed in the hope that it will be useful, |
| 9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 11 | * GNU General Public License for more details. |
| 12 | * |
| 13 | * You should have received a copy of the GNU General Public License along |
| 14 | * with this program; if not, write to the Free Software Foundation, Inc., |
| 15 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| 16 | */ |
| 17 | |
| 18 | #define _GNU_SOURCE |
| 19 | #include <errno.h> |
| 20 | #include <fcntl.h> |
| 21 | #include <stdlib.h> |
| 22 | #include <stdio.h> |
| 23 | #include <string.h> |
| 24 | #include <unistd.h> |
| 25 | #include <inttypes.h> |
| 26 | |
| 27 | #include <common/common.h> |
| 28 | #include <common/kernel-ctl/kernel-ctl.h> |
| 29 | #include <common/sessiond-comm/sessiond-comm.h> |
| 30 | |
| 31 | #include "consumer.h" |
| 32 | #include "kernel.h" |
| 33 | #include "kern-modules.h" |
| 34 | |
| 35 | /* |
| 36 | * Add context on a kernel channel. |
| 37 | */ |
| 38 | int kernel_add_channel_context(struct ltt_kernel_channel *chan, |
| 39 | struct lttng_kernel_context *ctx) |
| 40 | { |
| 41 | int ret; |
| 42 | |
| 43 | assert(chan); |
| 44 | assert(ctx); |
| 45 | |
| 46 | DBG("Adding context to channel %s", chan->channel->name); |
| 47 | ret = kernctl_add_context(chan->fd, ctx); |
| 48 | if (ret < 0) { |
| 49 | if (errno != EEXIST) { |
| 50 | PERROR("add context ioctl"); |
| 51 | } else { |
| 52 | /* If EEXIST, we just ignore the error */ |
| 53 | ret = 0; |
| 54 | } |
| 55 | goto error; |
| 56 | } |
| 57 | |
| 58 | chan->ctx = zmalloc(sizeof(struct lttng_kernel_context)); |
| 59 | if (chan->ctx == NULL) { |
| 60 | PERROR("zmalloc event context"); |
| 61 | goto error; |
| 62 | } |
| 63 | |
| 64 | memcpy(chan->ctx, ctx, sizeof(struct lttng_kernel_context)); |
| 65 | |
| 66 | return 0; |
| 67 | |
| 68 | error: |
| 69 | return ret; |
| 70 | } |
| 71 | |
| 72 | /* |
| 73 | * Create a new kernel session, register it to the kernel tracer and add it to |
| 74 | * the session daemon session. |
| 75 | */ |
| 76 | int kernel_create_session(struct ltt_session *session, int tracer_fd) |
| 77 | { |
| 78 | int ret; |
| 79 | struct ltt_kernel_session *lks; |
| 80 | |
| 81 | assert(session); |
| 82 | |
| 83 | /* Allocate data structure */ |
| 84 | lks = trace_kernel_create_session(); |
| 85 | if (lks == NULL) { |
| 86 | ret = -1; |
| 87 | goto error; |
| 88 | } |
| 89 | |
| 90 | /* Kernel tracer session creation */ |
| 91 | ret = kernctl_create_session(tracer_fd); |
| 92 | if (ret < 0) { |
| 93 | PERROR("ioctl kernel create session"); |
| 94 | goto error; |
| 95 | } |
| 96 | |
| 97 | lks->fd = ret; |
| 98 | /* Prevent fd duplication after execlp() */ |
| 99 | ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC); |
| 100 | if (ret < 0) { |
| 101 | PERROR("fcntl session fd"); |
| 102 | } |
| 103 | |
| 104 | lks->id = session->id; |
| 105 | lks->consumer_fds_sent = 0; |
| 106 | session->kernel_session = lks; |
| 107 | |
| 108 | DBG("Kernel session created (fd: %d)", lks->fd); |
| 109 | |
| 110 | return 0; |
| 111 | |
| 112 | error: |
| 113 | return ret; |
| 114 | } |
| 115 | |
| 116 | /* |
| 117 | * Create a kernel channel, register it to the kernel tracer and add it to the |
| 118 | * kernel session. |
| 119 | */ |
| 120 | int kernel_create_channel(struct ltt_kernel_session *session, |
| 121 | struct lttng_channel *chan) |
| 122 | { |
| 123 | int ret; |
| 124 | struct ltt_kernel_channel *lkc; |
| 125 | |
| 126 | assert(session); |
| 127 | assert(chan); |
| 128 | |
| 129 | /* Allocate kernel channel */ |
| 130 | lkc = trace_kernel_create_channel(chan); |
| 131 | if (lkc == NULL) { |
| 132 | goto error; |
| 133 | } |
| 134 | |
| 135 | DBG3("Kernel create channel %s with attr: %d, %" PRIu64 ", %" PRIu64 ", %u, %u, %d", |
| 136 | chan->name, lkc->channel->attr.overwrite, |
| 137 | lkc->channel->attr.subbuf_size, lkc->channel->attr.num_subbuf, |
| 138 | lkc->channel->attr.switch_timer_interval, lkc->channel->attr.read_timer_interval, |
| 139 | lkc->channel->attr.output); |
| 140 | |
| 141 | /* Kernel tracer channel creation */ |
| 142 | ret = kernctl_create_channel(session->fd, &lkc->channel->attr); |
| 143 | if (ret < 0) { |
| 144 | PERROR("ioctl kernel create channel"); |
| 145 | goto error; |
| 146 | } |
| 147 | |
| 148 | /* Setup the channel fd */ |
| 149 | lkc->fd = ret; |
| 150 | /* Prevent fd duplication after execlp() */ |
| 151 | ret = fcntl(lkc->fd, F_SETFD, FD_CLOEXEC); |
| 152 | if (ret < 0) { |
| 153 | PERROR("fcntl session fd"); |
| 154 | } |
| 155 | |
| 156 | /* Add channel to session */ |
| 157 | cds_list_add(&lkc->list, &session->channel_list.head); |
| 158 | session->channel_count++; |
| 159 | lkc->session = session; |
| 160 | |
| 161 | DBG("Kernel channel %s created (fd: %d)", lkc->channel->name, lkc->fd); |
| 162 | |
| 163 | return 0; |
| 164 | |
| 165 | error: |
| 166 | return -1; |
| 167 | } |
| 168 | |
| 169 | /* |
| 170 | * Create a kernel event, enable it to the kernel tracer and add it to the |
| 171 | * channel event list of the kernel session. |
| 172 | */ |
| 173 | int kernel_create_event(struct lttng_event *ev, |
| 174 | struct ltt_kernel_channel *channel) |
| 175 | { |
| 176 | int ret; |
| 177 | struct ltt_kernel_event *event; |
| 178 | |
| 179 | assert(ev); |
| 180 | assert(channel); |
| 181 | |
| 182 | event = trace_kernel_create_event(ev); |
| 183 | if (event == NULL) { |
| 184 | ret = -1; |
| 185 | goto error; |
| 186 | } |
| 187 | |
| 188 | ret = kernctl_create_event(channel->fd, event->event); |
| 189 | if (ret < 0) { |
| 190 | switch (errno) { |
| 191 | case EEXIST: |
| 192 | break; |
| 193 | case ENOSYS: |
| 194 | WARN("Event type not implemented"); |
| 195 | break; |
| 196 | default: |
| 197 | PERROR("create event ioctl"); |
| 198 | } |
| 199 | ret = -errno; |
| 200 | goto free_event; |
| 201 | } |
| 202 | |
| 203 | /* |
| 204 | * LTTNG_KERNEL_SYSCALL event creation will return 0 on success. |
| 205 | */ |
| 206 | if (ret == 0 && event->event->instrumentation == LTTNG_KERNEL_SYSCALL) { |
| 207 | DBG2("Kernel event syscall creation success"); |
| 208 | /* |
| 209 | * We use fd == -1 to ensure that we never trigger a close of fd |
| 210 | * 0. |
| 211 | */ |
| 212 | event->fd = -1; |
| 213 | goto add_list; |
| 214 | } |
| 215 | |
| 216 | event->fd = ret; |
| 217 | /* Prevent fd duplication after execlp() */ |
| 218 | ret = fcntl(event->fd, F_SETFD, FD_CLOEXEC); |
| 219 | if (ret < 0) { |
| 220 | PERROR("fcntl session fd"); |
| 221 | } |
| 222 | |
| 223 | add_list: |
| 224 | /* Add event to event list */ |
| 225 | cds_list_add(&event->list, &channel->events_list.head); |
| 226 | channel->event_count++; |
| 227 | |
| 228 | DBG("Event %s created (fd: %d)", ev->name, event->fd); |
| 229 | |
| 230 | return 0; |
| 231 | |
| 232 | free_event: |
| 233 | free(event); |
| 234 | error: |
| 235 | return ret; |
| 236 | } |
| 237 | |
| 238 | /* |
| 239 | * Disable a kernel channel. |
| 240 | */ |
| 241 | int kernel_disable_channel(struct ltt_kernel_channel *chan) |
| 242 | { |
| 243 | int ret; |
| 244 | |
| 245 | assert(chan); |
| 246 | |
| 247 | ret = kernctl_disable(chan->fd); |
| 248 | if (ret < 0) { |
| 249 | PERROR("disable chan ioctl"); |
| 250 | ret = errno; |
| 251 | goto error; |
| 252 | } |
| 253 | |
| 254 | chan->enabled = 0; |
| 255 | DBG("Kernel channel %s disabled (fd: %d)", chan->channel->name, chan->fd); |
| 256 | |
| 257 | return 0; |
| 258 | |
| 259 | error: |
| 260 | return ret; |
| 261 | } |
| 262 | |
| 263 | /* |
| 264 | * Enable a kernel channel. |
| 265 | */ |
| 266 | int kernel_enable_channel(struct ltt_kernel_channel *chan) |
| 267 | { |
| 268 | int ret; |
| 269 | |
| 270 | assert(chan); |
| 271 | |
| 272 | ret = kernctl_enable(chan->fd); |
| 273 | if (ret < 0 && errno != EEXIST) { |
| 274 | PERROR("Enable kernel chan"); |
| 275 | goto error; |
| 276 | } |
| 277 | |
| 278 | chan->enabled = 1; |
| 279 | DBG("Kernel channel %s enabled (fd: %d)", chan->channel->name, chan->fd); |
| 280 | |
| 281 | return 0; |
| 282 | |
| 283 | error: |
| 284 | return ret; |
| 285 | } |
| 286 | |
| 287 | /* |
| 288 | * Enable a kernel event. |
| 289 | */ |
| 290 | int kernel_enable_event(struct ltt_kernel_event *event) |
| 291 | { |
| 292 | int ret; |
| 293 | |
| 294 | assert(event); |
| 295 | |
| 296 | ret = kernctl_enable(event->fd); |
| 297 | if (ret < 0) { |
| 298 | switch (errno) { |
| 299 | case EEXIST: |
| 300 | ret = LTTNG_ERR_KERN_EVENT_EXIST; |
| 301 | break; |
| 302 | default: |
| 303 | PERROR("enable kernel event"); |
| 304 | break; |
| 305 | } |
| 306 | goto error; |
| 307 | } |
| 308 | |
| 309 | event->enabled = 1; |
| 310 | DBG("Kernel event %s enabled (fd: %d)", event->event->name, event->fd); |
| 311 | |
| 312 | return 0; |
| 313 | |
| 314 | error: |
| 315 | return ret; |
| 316 | } |
| 317 | |
| 318 | /* |
| 319 | * Disable a kernel event. |
| 320 | */ |
| 321 | int kernel_disable_event(struct ltt_kernel_event *event) |
| 322 | { |
| 323 | int ret; |
| 324 | |
| 325 | assert(event); |
| 326 | |
| 327 | ret = kernctl_disable(event->fd); |
| 328 | if (ret < 0) { |
| 329 | switch (errno) { |
| 330 | case EEXIST: |
| 331 | ret = LTTNG_ERR_KERN_EVENT_EXIST; |
| 332 | break; |
| 333 | default: |
| 334 | PERROR("disable kernel event"); |
| 335 | break; |
| 336 | } |
| 337 | goto error; |
| 338 | } |
| 339 | |
| 340 | event->enabled = 0; |
| 341 | DBG("Kernel event %s disabled (fd: %d)", event->event->name, event->fd); |
| 342 | |
| 343 | return 0; |
| 344 | |
| 345 | error: |
| 346 | return ret; |
| 347 | } |
| 348 | |
| 349 | /* |
| 350 | * Create kernel metadata, open from the kernel tracer and add it to the |
| 351 | * kernel session. |
| 352 | */ |
| 353 | int kernel_open_metadata(struct ltt_kernel_session *session) |
| 354 | { |
| 355 | int ret; |
| 356 | struct ltt_kernel_metadata *lkm = NULL; |
| 357 | |
| 358 | assert(session); |
| 359 | |
| 360 | /* Allocate kernel metadata */ |
| 361 | lkm = trace_kernel_create_metadata(); |
| 362 | if (lkm == NULL) { |
| 363 | goto error; |
| 364 | } |
| 365 | |
| 366 | /* Kernel tracer metadata creation */ |
| 367 | ret = kernctl_open_metadata(session->fd, &lkm->conf->attr); |
| 368 | if (ret < 0) { |
| 369 | goto error_open; |
| 370 | } |
| 371 | |
| 372 | lkm->fd = ret; |
| 373 | /* Prevent fd duplication after execlp() */ |
| 374 | ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC); |
| 375 | if (ret < 0) { |
| 376 | PERROR("fcntl session fd"); |
| 377 | } |
| 378 | |
| 379 | session->metadata = lkm; |
| 380 | |
| 381 | DBG("Kernel metadata opened (fd: %d)", lkm->fd); |
| 382 | |
| 383 | return 0; |
| 384 | |
| 385 | error_open: |
| 386 | trace_kernel_destroy_metadata(lkm); |
| 387 | error: |
| 388 | return -1; |
| 389 | } |
| 390 | |
| 391 | /* |
| 392 | * Start tracing session. |
| 393 | */ |
| 394 | int kernel_start_session(struct ltt_kernel_session *session) |
| 395 | { |
| 396 | int ret; |
| 397 | |
| 398 | assert(session); |
| 399 | |
| 400 | ret = kernctl_start_session(session->fd); |
| 401 | if (ret < 0) { |
| 402 | PERROR("ioctl start session"); |
| 403 | goto error; |
| 404 | } |
| 405 | |
| 406 | DBG("Kernel session started"); |
| 407 | |
| 408 | return 0; |
| 409 | |
| 410 | error: |
| 411 | return ret; |
| 412 | } |
| 413 | |
| 414 | /* |
| 415 | * Make a kernel wait to make sure in-flight probe have completed. |
| 416 | */ |
| 417 | void kernel_wait_quiescent(int fd) |
| 418 | { |
| 419 | int ret; |
| 420 | |
| 421 | DBG("Kernel quiescent wait on %d", fd); |
| 422 | |
| 423 | ret = kernctl_wait_quiescent(fd); |
| 424 | if (ret < 0) { |
| 425 | PERROR("wait quiescent ioctl"); |
| 426 | ERR("Kernel quiescent wait failed"); |
| 427 | } |
| 428 | } |
| 429 | |
| 430 | /* |
| 431 | * Kernel calibrate |
| 432 | */ |
| 433 | int kernel_calibrate(int fd, struct lttng_kernel_calibrate *calibrate) |
| 434 | { |
| 435 | int ret; |
| 436 | |
| 437 | assert(calibrate); |
| 438 | |
| 439 | ret = kernctl_calibrate(fd, calibrate); |
| 440 | if (ret < 0) { |
| 441 | PERROR("calibrate ioctl"); |
| 442 | return -1; |
| 443 | } |
| 444 | |
| 445 | return 0; |
| 446 | } |
| 447 | |
| 448 | |
| 449 | /* |
| 450 | * Force flush buffer of metadata. |
| 451 | */ |
| 452 | int kernel_metadata_flush_buffer(int fd) |
| 453 | { |
| 454 | int ret; |
| 455 | |
| 456 | ret = kernctl_buffer_flush(fd); |
| 457 | if (ret < 0) { |
| 458 | ERR("Fail to flush metadata buffers %d (ret: %d)", fd, ret); |
| 459 | } |
| 460 | |
| 461 | return 0; |
| 462 | } |
| 463 | |
| 464 | /* |
| 465 | * Force flush buffer for channel. |
| 466 | */ |
| 467 | int kernel_flush_buffer(struct ltt_kernel_channel *channel) |
| 468 | { |
| 469 | int ret; |
| 470 | struct ltt_kernel_stream *stream; |
| 471 | |
| 472 | assert(channel); |
| 473 | |
| 474 | DBG("Flush buffer for channel %s", channel->channel->name); |
| 475 | |
| 476 | cds_list_for_each_entry(stream, &channel->stream_list.head, list) { |
| 477 | DBG("Flushing channel stream %d", stream->fd); |
| 478 | ret = kernctl_buffer_flush(stream->fd); |
| 479 | if (ret < 0) { |
| 480 | PERROR("ioctl"); |
| 481 | ERR("Fail to flush buffer for stream %d (ret: %d)", |
| 482 | stream->fd, ret); |
| 483 | } |
| 484 | } |
| 485 | |
| 486 | return 0; |
| 487 | } |
| 488 | |
| 489 | /* |
| 490 | * Stop tracing session. |
| 491 | */ |
| 492 | int kernel_stop_session(struct ltt_kernel_session *session) |
| 493 | { |
| 494 | int ret; |
| 495 | |
| 496 | assert(session); |
| 497 | |
| 498 | ret = kernctl_stop_session(session->fd); |
| 499 | if (ret < 0) { |
| 500 | goto error; |
| 501 | } |
| 502 | |
| 503 | DBG("Kernel session stopped"); |
| 504 | |
| 505 | return 0; |
| 506 | |
| 507 | error: |
| 508 | return ret; |
| 509 | } |
| 510 | |
| 511 | /* |
| 512 | * Open stream of channel, register it to the kernel tracer and add it |
| 513 | * to the stream list of the channel. |
| 514 | * |
| 515 | * Return the number of created stream. Else, a negative value. |
| 516 | */ |
| 517 | int kernel_open_channel_stream(struct ltt_kernel_channel *channel) |
| 518 | { |
| 519 | int ret, count = 0; |
| 520 | struct ltt_kernel_stream *lks; |
| 521 | |
| 522 | assert(channel); |
| 523 | |
| 524 | while ((ret = kernctl_create_stream(channel->fd)) >= 0) { |
| 525 | lks = trace_kernel_create_stream(channel->channel->name, count); |
| 526 | if (lks == NULL) { |
| 527 | ret = close(ret); |
| 528 | if (ret) { |
| 529 | PERROR("close"); |
| 530 | } |
| 531 | goto error; |
| 532 | } |
| 533 | |
| 534 | lks->fd = ret; |
| 535 | /* Prevent fd duplication after execlp() */ |
| 536 | ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC); |
| 537 | if (ret < 0) { |
| 538 | PERROR("fcntl session fd"); |
| 539 | } |
| 540 | |
| 541 | lks->tracefile_size = channel->channel->attr.tracefile_size; |
| 542 | lks->tracefile_count = channel->channel->attr.tracefile_count; |
| 543 | |
| 544 | /* Add stream to channe stream list */ |
| 545 | cds_list_add(&lks->list, &channel->stream_list.head); |
| 546 | channel->stream_count++; |
| 547 | |
| 548 | /* Increment counter which represent CPU number. */ |
| 549 | count++; |
| 550 | |
| 551 | DBG("Kernel stream %s created (fd: %d, state: %d)", lks->name, lks->fd, |
| 552 | lks->state); |
| 553 | } |
| 554 | |
| 555 | return channel->stream_count; |
| 556 | |
| 557 | error: |
| 558 | return -1; |
| 559 | } |
| 560 | |
| 561 | /* |
| 562 | * Open the metadata stream and set it to the kernel session. |
| 563 | */ |
| 564 | int kernel_open_metadata_stream(struct ltt_kernel_session *session) |
| 565 | { |
| 566 | int ret; |
| 567 | |
| 568 | assert(session); |
| 569 | |
| 570 | ret = kernctl_create_stream(session->metadata->fd); |
| 571 | if (ret < 0) { |
| 572 | PERROR("kernel create metadata stream"); |
| 573 | goto error; |
| 574 | } |
| 575 | |
| 576 | DBG("Kernel metadata stream created (fd: %d)", ret); |
| 577 | session->metadata_stream_fd = ret; |
| 578 | /* Prevent fd duplication after execlp() */ |
| 579 | ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC); |
| 580 | if (ret < 0) { |
| 581 | PERROR("fcntl session fd"); |
| 582 | } |
| 583 | |
| 584 | return 0; |
| 585 | |
| 586 | error: |
| 587 | return -1; |
| 588 | } |
| 589 | |
| 590 | /* |
| 591 | * Get the event list from the kernel tracer and return the number of elements. |
| 592 | */ |
| 593 | ssize_t kernel_list_events(int tracer_fd, struct lttng_event **events) |
| 594 | { |
| 595 | int fd, pos, ret; |
| 596 | char *event; |
| 597 | size_t nbmem, count = 0; |
| 598 | FILE *fp; |
| 599 | struct lttng_event *elist; |
| 600 | |
| 601 | assert(events); |
| 602 | |
| 603 | fd = kernctl_tracepoint_list(tracer_fd); |
| 604 | if (fd < 0) { |
| 605 | PERROR("kernel tracepoint list"); |
| 606 | goto error; |
| 607 | } |
| 608 | |
| 609 | fp = fdopen(fd, "r"); |
| 610 | if (fp == NULL) { |
| 611 | PERROR("kernel tracepoint list fdopen"); |
| 612 | goto error_fp; |
| 613 | } |
| 614 | |
| 615 | /* |
| 616 | * Init memory size counter |
| 617 | * See kernel-ctl.h for explanation of this value |
| 618 | */ |
| 619 | nbmem = KERNEL_EVENT_INIT_LIST_SIZE; |
| 620 | elist = zmalloc(sizeof(struct lttng_event) * nbmem); |
| 621 | if (elist == NULL) { |
| 622 | PERROR("alloc list events"); |
| 623 | count = -ENOMEM; |
| 624 | goto end; |
| 625 | } |
| 626 | |
| 627 | while (fscanf(fp, "event { name = %m[^;]; };%n\n", &event, &pos) == 1) { |
| 628 | if (count >= nbmem) { |
| 629 | struct lttng_event *new_elist; |
| 630 | |
| 631 | DBG("Reallocating event list from %zu to %zu bytes", nbmem, |
| 632 | nbmem * 2); |
| 633 | /* Double the size */ |
| 634 | nbmem <<= 1; |
| 635 | new_elist = realloc(elist, nbmem * sizeof(struct lttng_event)); |
| 636 | if (new_elist == NULL) { |
| 637 | PERROR("realloc list events"); |
| 638 | free(event); |
| 639 | free(elist); |
| 640 | count = -ENOMEM; |
| 641 | goto end; |
| 642 | } |
| 643 | elist = new_elist; |
| 644 | } |
| 645 | strncpy(elist[count].name, event, LTTNG_SYMBOL_NAME_LEN); |
| 646 | elist[count].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0'; |
| 647 | elist[count].enabled = -1; |
| 648 | count++; |
| 649 | free(event); |
| 650 | } |
| 651 | |
| 652 | *events = elist; |
| 653 | DBG("Kernel list events done (%zu events)", count); |
| 654 | end: |
| 655 | ret = fclose(fp); /* closes both fp and fd */ |
| 656 | if (ret) { |
| 657 | PERROR("fclose"); |
| 658 | } |
| 659 | return count; |
| 660 | |
| 661 | error_fp: |
| 662 | ret = close(fd); |
| 663 | if (ret) { |
| 664 | PERROR("close"); |
| 665 | } |
| 666 | error: |
| 667 | return -1; |
| 668 | } |
| 669 | |
| 670 | /* |
| 671 | * Get kernel version and validate it. |
| 672 | */ |
| 673 | int kernel_validate_version(int tracer_fd) |
| 674 | { |
| 675 | int ret; |
| 676 | struct lttng_kernel_tracer_version version; |
| 677 | |
| 678 | ret = kernctl_tracer_version(tracer_fd, &version); |
| 679 | if (ret < 0) { |
| 680 | ERR("Failed at getting the lttng-modules version"); |
| 681 | goto error; |
| 682 | } |
| 683 | |
| 684 | /* Validate version */ |
| 685 | if (version.major != KERN_MODULES_PRE_MAJOR |
| 686 | && version.major != KERN_MODULES_MAJOR) { |
| 687 | goto error_version; |
| 688 | } |
| 689 | |
| 690 | DBG2("Kernel tracer version validated (major version %d)", version.major); |
| 691 | return 0; |
| 692 | |
| 693 | error_version: |
| 694 | ERR("Kernel major version %d is not compatible (supporting <= %d)", |
| 695 | version.major, KERN_MODULES_MAJOR) |
| 696 | ret = -1; |
| 697 | |
| 698 | error: |
| 699 | return ret; |
| 700 | } |
| 701 | |
| 702 | /* |
| 703 | * Kernel work-arounds called at the start of sessiond main(). |
| 704 | */ |
| 705 | int init_kernel_workarounds(void) |
| 706 | { |
| 707 | int ret; |
| 708 | FILE *fp; |
| 709 | |
| 710 | /* |
| 711 | * boot_id needs to be read once before being used concurrently |
| 712 | * to deal with a Linux kernel race. A fix is proposed for |
| 713 | * upstream, but the work-around is needed for older kernels. |
| 714 | */ |
| 715 | fp = fopen("/proc/sys/kernel/random/boot_id", "r"); |
| 716 | if (!fp) { |
| 717 | goto end_boot_id; |
| 718 | } |
| 719 | while (!feof(fp)) { |
| 720 | char buf[37] = ""; |
| 721 | |
| 722 | ret = fread(buf, 1, sizeof(buf), fp); |
| 723 | if (ret < 0) { |
| 724 | /* Ignore error, we don't really care */ |
| 725 | } |
| 726 | } |
| 727 | ret = fclose(fp); |
| 728 | if (ret) { |
| 729 | PERROR("fclose"); |
| 730 | } |
| 731 | end_boot_id: |
| 732 | return 0; |
| 733 | } |
| 734 | |
| 735 | /* |
| 736 | * Complete teardown of a kernel session. |
| 737 | */ |
| 738 | void kernel_destroy_session(struct ltt_kernel_session *ksess) |
| 739 | { |
| 740 | if (ksess == NULL) { |
| 741 | DBG3("No kernel session when tearing down session"); |
| 742 | return; |
| 743 | } |
| 744 | |
| 745 | DBG("Tearing down kernel session"); |
| 746 | |
| 747 | /* Close any relayd session */ |
| 748 | consumer_output_send_destroy_relayd(ksess->consumer); |
| 749 | |
| 750 | trace_kernel_destroy_session(ksess); |
| 751 | } |
| 752 | |
| 753 | /* |
| 754 | * Destroy a kernel channel object. It does not do anything on the tracer side. |
| 755 | */ |
| 756 | void kernel_destroy_channel(struct ltt_kernel_channel *kchan) |
| 757 | { |
| 758 | struct ltt_kernel_session *ksess = NULL; |
| 759 | |
| 760 | assert(kchan); |
| 761 | assert(kchan->channel); |
| 762 | |
| 763 | DBG3("Kernel destroy channel %s", kchan->channel->name); |
| 764 | |
| 765 | /* Update channel count of associated session. */ |
| 766 | if (kchan->session) { |
| 767 | /* Keep pointer reference so we can update it after the destroy. */ |
| 768 | ksess = kchan->session; |
| 769 | } |
| 770 | |
| 771 | trace_kernel_destroy_channel(kchan); |
| 772 | |
| 773 | /* |
| 774 | * At this point the kernel channel is not visible anymore. This is safe |
| 775 | * since in order to work on a visible kernel session, the tracing session |
| 776 | * lock (ltt_session.lock) MUST be acquired. |
| 777 | */ |
| 778 | if (ksess) { |
| 779 | ksess->channel_count--; |
| 780 | } |
| 781 | } |