ltt-sessiond/kernel-ctl.c

   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; either version 2
   7  * of the License, or (at your option) any later version.
   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 "lttngerr.h"
  28 #include "libkernelctl.h"
  29 #include "kernel-ctl.h"
  30
  31 /*
  32  *  kernel_add_channel_context
  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                 perror("add context ioctl");
  45                 goto error;
  46         }
  47
  48         chan->ctx = malloc(sizeof(struct lttng_kernel_context));
  49         if (chan->ctx == NULL) {
  50                 perror("malloc event context");
  51                 goto error;
  52         }
  53
  54         memcpy(chan->ctx, ctx, sizeof(struct lttng_kernel_context));
  55
  56         return 0;
  57
  58 error:
  59         return ret;
  60 }
  61
  62 /*
  63  *  kernel_add_event_context
  64  *
  65  *  Add context on a kernel event.
  66  */
  67 int kernel_add_event_context(struct ltt_kernel_event *event,
  68                 struct lttng_kernel_context *ctx)
  69 {
  70         int ret;
  71
  72         DBG("Adding context to event %s", event->event->name);
  73         ret = kernctl_add_context(event->fd, ctx);
  74         if (ret < 0) {
  75                 perror("add context ioctl");
  76                 goto error;
  77         }
  78
  79         event->ctx = malloc(sizeof(struct lttng_kernel_context));
  80         if (event->ctx == NULL) {
  81                 perror("malloc event context");
  82                 goto error;
  83         }
  84
  85         memcpy(event->ctx, ctx, sizeof(struct lttng_kernel_context));
  86
  87         return 0;
  88
  89 error:
  90         return ret;
  91 }
  92
  93 /*
  94  *  kernel_create_session
  95  *
  96  *  Create a new kernel session, register it to the kernel tracer and add it to
  97  *  the session daemon session.
  98  */
  99 int kernel_create_session(struct ltt_session *session, int tracer_fd)
 100 {
 101         int ret;
 102         struct ltt_kernel_session *lks;
 103
 104         /* Allocate data structure */
 105         lks = trace_create_kernel_session();
 106         if (lks == NULL) {
 107                 ret = -1;
 108                 goto error;
 109         }
 110
 111         /* Kernel tracer session creation */
 112         ret = kernctl_create_session(tracer_fd);
 113         if (ret < 0) {
 114                 perror("ioctl kernel create session");
 115                 goto error;
 116         }
 117
 118         lks->fd = ret;
 119         /* Prevent fd duplication after execlp() */
 120         ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
 121         if (ret < 0) {
 122                 perror("fcntl session fd");
 123         }
 124
 125         lks->kconsumer_fds_sent = 0;
 126         session->kernel_session = lks;
 127
 128         DBG("Kernel session created (fd: %d)", lks->fd);
 129
 130         return 0;
 131
 132 error:
 133         return ret;
 134 }
 135
 136 /*
 137  *  kernel_create_channel
 138  *
 139  *  Create a kernel channel, register it to the kernel tracer and add it to the
 140  *  kernel session.
 141  */
 142 int kernel_create_channel(struct ltt_kernel_session *session, struct lttng_channel *chan, char *path)
 143 {
 144         int ret;
 145         struct ltt_kernel_channel *lkc;
 146
 147         /* Allocate kernel channel */
 148         lkc = trace_create_kernel_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  *  kernel_create_event
 183  *
 184  *  Create a kernel event, enable it to the kernel tracer and add it to the
 185  *  channel event list of the kernel session.
 186  */
 187 int kernel_create_event(struct lttng_event *ev, struct ltt_kernel_channel *channel)
 188 {
 189         int ret;
 190         struct ltt_kernel_event *event;
 191
 192         event = trace_create_kernel_event(ev);
 193         if (event == NULL) {
 194                 goto error;
 195         }
 196
 197         ret = kernctl_create_event(channel->fd, event->event);
 198         if (ret < 0) {
 199                 perror("create event ioctl");
 200                 goto free_event;
 201         }
 202
 203         event->fd = ret;
 204         /* Prevent fd duplication after execlp() */
 205         ret = fcntl(event->fd, F_SETFD, FD_CLOEXEC);
 206         if (ret < 0) {
 207                 perror("fcntl session fd");
 208         }
 209
 210         /* Add event to event list */
 211         cds_list_add(&event->list, &channel->events_list.head);
 212         DBG("Event %s created (fd: %d)", ev->name, event->fd);
 213
 214         return 0;
 215
 216 free_event:
 217         free(event);
 218 error:
 219         return -1;
 220 }
 221
 222 /*
 223  *  kernel_disable_channel
 224  *
 225  *  Disable a kernel channel.
 226  */
 227 int kernel_disable_channel(struct ltt_kernel_channel *chan)
 228 {
 229         int ret;
 230
 231         ret = kernctl_disable(chan->fd);
 232         if (ret < 0) {
 233                 perror("disable chan ioctl");
 234                 ret = errno;
 235                 goto error;
 236         }
 237
 238         chan->enabled = 0;
 239         DBG("Kernel channel %s disabled (fd: %d)", chan->channel->name, chan->fd);
 240
 241         return 0;
 242
 243 error:
 244         return ret;
 245 }
 246
 247 /*
 248  *  kernel_enable_channel
 249  *
 250  *  Enable a kernel channel.
 251  */
 252 int kernel_enable_channel(struct ltt_kernel_channel *chan)
 253 {
 254         int ret;
 255
 256         ret = kernctl_enable(chan->fd);
 257         if (ret < 0) {
 258                 perror("enable chan ioctl");
 259                 ret = errno;
 260                 goto error;
 261         }
 262
 263         chan->enabled = 1;
 264         DBG("Kernel channel %s enabled (fd: %d)", chan->channel->name, chan->fd);
 265
 266         return 0;
 267
 268 error:
 269         return ret;
 270 }
 271
 272 /*
 273  *  kernel_enable_event
 274  *
 275  *  Enable a kernel event.
 276  */
 277 int kernel_enable_event(struct ltt_kernel_event *event)
 278 {
 279         int ret;
 280
 281         ret = kernctl_enable(event->fd);
 282         if (ret < 0) {
 283                 perror("enable event ioctl");
 284                 goto error;
 285         }
 286
 287         event->enabled = 1;
 288         DBG("Kernel event %s enabled (fd: %d)", event->event->name, event->fd);
 289
 290         return 0;
 291
 292 error:
 293         return ret;
 294 }
 295
 296 /*
 297  *  kernel_disable_event
 298  *
 299  *  Disable a kernel event.
 300  */
 301 int kernel_disable_event(struct ltt_kernel_event *event)
 302 {
 303         int ret;
 304
 305         ret = kernctl_disable(event->fd);
 306         if (ret < 0) {
 307                 perror("disable event ioctl");
 308                 goto error;
 309         }
 310
 311         event->enabled = 0;
 312         DBG("Kernel event %s disabled (fd: %d)", event->event->name, event->fd);
 313
 314         return 0;
 315
 316 error:
 317         return ret;
 318 }
 319
 320 /*
 321  *  kernel_open_metadata
 322  *
 323  *  Create kernel metadata, open from the kernel tracer and add it to the
 324  *  kernel session.
 325  */
 326 int kernel_open_metadata(struct ltt_kernel_session *session, char *path)
 327 {
 328         int ret;
 329         struct ltt_kernel_metadata *lkm;
 330
 331         /* Allocate kernel metadata */
 332         lkm = trace_create_kernel_metadata(path);
 333         if (lkm == NULL) {
 334                 goto error;
 335         }
 336
 337         /* Kernel tracer metadata creation */
 338         ret = kernctl_open_metadata(session->fd, &lkm->conf->attr);
 339         if (ret < 0) {
 340                 goto error;
 341         }
 342
 343         lkm->fd = ret;
 344         /* Prevent fd duplication after execlp() */
 345         ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC);
 346         if (ret < 0) {
 347                 perror("fcntl session fd");
 348         }
 349
 350         session->metadata = lkm;
 351
 352         DBG("Kernel metadata opened (fd: %d and path: %s)", lkm->fd, lkm->pathname);
 353
 354         return 0;
 355
 356 error:
 357         return -1;
 358 }
 359
 360 /*
 361  *  kernel_start_session
 362  *
 363  *  Start tracing session.
 364  */
 365 int kernel_start_session(struct ltt_kernel_session *session)
 366 {
 367         int ret;
 368
 369         ret = kernctl_start_session(session->fd);
 370         if (ret < 0) {
 371                 perror("ioctl start session");
 372                 goto error;
 373         }
 374
 375         DBG("Kernel session started");
 376
 377         return 0;
 378
 379 error:
 380         return ret;
 381 }
 382
 383 /*
 384  *  kernel_wait_quiescent
 385  *
 386  *  Make a kernel wait to make sure in-flight probe have completed.
 387  */
 388 void kernel_wait_quiescent(int fd)
 389 {
 390         int ret;
 391
 392         DBG("Kernel quiescent wait on %d", fd);
 393
 394         ret = kernctl_wait_quiescent(fd);
 395         if (ret < 0) {
 396                 perror("wait quiescent ioctl");
 397                 ERR("Kernel quiescent wait failed");
 398         }
 399 }
 400
 401 /*
 402  *  kernel_metadata_flush_buffer
 403  *
 404  *  Force flush buffer of metadata.
 405  */
 406 int kernel_metadata_flush_buffer(int fd)
 407 {
 408         int ret;
 409
 410         ret = kernctl_buffer_flush(fd);
 411         if (ret < 0) {
 412                 ERR("Fail to flush metadata buffers %d (ret: %d", fd, ret);
 413         }
 414
 415         return 0;
 416 }
 417
 418 /*
 419  *  kernel_flush_buffer
 420  *
 421  *  Force flush buffer for channel.
 422  */
 423 int kernel_flush_buffer(struct ltt_kernel_channel *channel)
 424 {
 425         int ret;
 426         struct ltt_kernel_stream *stream;
 427
 428         DBG("Flush buffer for channel %s", channel->channel->name);
 429
 430         cds_list_for_each_entry(stream, &channel->stream_list.head, list) {
 431                 DBG("Flushing channel stream %d", stream->fd);
 432                 ret = kernctl_buffer_flush(stream->fd);
 433                 if (ret < 0) {
 434                         perror("ioctl");
 435                         ERR("Fail to flush buffer for stream %d (ret: %d)",
 436                                         stream->fd, ret);
 437                 }
 438         }
 439
 440         return 0;
 441 }
 442
 443 /*
 444  *  kernel_stop_session
 445  *
 446  *  Stop tracing session.
 447  */
 448 int kernel_stop_session(struct ltt_kernel_session *session)
 449 {
 450         int ret;
 451
 452         ret = kernctl_stop_session(session->fd);
 453         if (ret < 0) {
 454                 goto error;
 455         }
 456
 457         DBG("Kernel session stopped");
 458
 459         return 0;
 460
 461 error:
 462         return ret;
 463 }
 464
 465 /*
 466  *  kernel_open_channel_stream
 467  *
 468  *  Open stream of channel, register it to the kernel tracer and add it
 469  *  to the stream list of the channel.
 470  *
 471  *  Return the number of created stream. Else, a negative value.
 472  */
 473 int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
 474 {
 475         int ret;
 476         struct ltt_kernel_stream *lks;
 477
 478         while ((ret = kernctl_create_stream(channel->fd)) > 0) {
 479                 lks = trace_create_kernel_stream();
 480                 if (lks == NULL) {
 481                         close(ret);
 482                         goto error;
 483                 }
 484
 485                 lks->fd = ret;
 486                 /* Prevent fd duplication after execlp() */
 487                 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
 488                 if (ret < 0) {
 489                         perror("fcntl session fd");
 490                 }
 491
 492                 ret = asprintf(&lks->pathname, "%s/%s_%d",
 493                                 channel->pathname, channel->channel->name, channel->stream_count);
 494                 if (ret < 0) {
 495                         perror("asprintf kernel create stream");
 496                         goto error;
 497                 }
 498
 499                 /* Add stream to channe stream list */
 500                 cds_list_add(&lks->list, &channel->stream_list.head);
 501                 channel->stream_count++;
 502
 503                 DBG("Kernel stream %d created (fd: %d, state: %d, path: %s)",
 504                                 channel->stream_count, lks->fd, lks->state, lks->pathname);
 505         }
 506
 507         return channel->stream_count;
 508
 509 error:
 510         return -1;
 511 }
 512
 513 /*
 514  *  kernel_open_metadata_stream
 515  *
 516  *  Open the metadata stream and set it to the kernel session.
 517  */
 518 int kernel_open_metadata_stream(struct ltt_kernel_session *session)
 519 {
 520         int ret;
 521
 522         ret = kernctl_create_stream(session->metadata->fd);
 523         if (ret < 0) {
 524                 perror("kernel create metadata stream");
 525                 goto error;
 526         }
 527
 528         DBG("Kernel metadata stream created (fd: %d)", ret);
 529         session->metadata_stream_fd = ret;
 530         /* Prevent fd duplication after execlp() */
 531         ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC);
 532         if (ret < 0) {
 533                 perror("fcntl session fd");
 534         }
 535
 536         return 0;
 537
 538 error:
 539         return -1;
 540 }
 541
 542 /*
 543  *  kernel_list_events
 544  *
 545  *  Get the event list from the kernel tracer and return that list in the CTF
 546  *  format.
 547  */
 548 ssize_t kernel_list_events(int tracer_fd, char **list)
 549 {
 550         int fd;
 551         char *buf, *line = NULL;
 552         size_t nb, nbmem, total = 0;
 553         ssize_t size;
 554         FILE *fp;
 555
 556         fd = kernctl_tracepoint_list(tracer_fd);
 557         if (fd < 0) {
 558                 perror("kernel tracepoint list");
 559                 goto error;
 560         }
 561
 562         fp = fdopen(fd, "r");
 563         if (fp == NULL) {
 564                 perror("kernel tracepoint list fdopen");
 565                 goto error;
 566         }
 567
 568         /*
 569          * Init memory size counter
 570          * See kernel-ctl.h for explanation of this value
 571          */
 572         nbmem = KERNEL_EVENT_LIST_SIZE;
 573         buf = malloc(nbmem);
 574
 575         while ((size = getline(&line, &nb, fp)) != -1) {
 576                 if (total + size > nbmem) {
 577                         DBG("Reallocating event list from %zd to %zd bytes", nbmem,
 578                                         total + size + KERNEL_EVENT_LIST_SIZE);
 579                         /* Adding the default size again */
 580                         nbmem = total + size + KERNEL_EVENT_LIST_SIZE;
 581                         buf = realloc(buf, nbmem);
 582                         if (buf == NULL) {
 583                                 perror("realloc list events");
 584                                 goto error;
 585                         }
 586                 }
 587                 memcpy(buf + total, line, size);
 588                 total += size;
 589         }
 590
 591         *list = buf;
 592
 593         DBG("Kernel list events done");
 594
 595         return total;
 596
 597 error:
 598         return -1;
 599 }