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; 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 "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         channel->event_count++;
 213
 214         DBG("Event %s created (fd: %d)", ev->name, event->fd);
 215
 216         return 0;
 217
 218 free_event:
 219         free(event);
 220 error:
 221         return -1;
 222 }
 223
 224 /*
 225  *  kernel_disable_channel
 226  *
 227  *  Disable a kernel channel.
 228  */
 229 int kernel_disable_channel(struct ltt_kernel_channel *chan)
 230 {
 231         int ret;
 232
 233         ret = kernctl_disable(chan->fd);
 234         if (ret < 0) {
 235                 perror("disable chan ioctl");
 236                 ret = errno;
 237                 goto error;
 238         }
 239
 240         chan->enabled = 0;
 241         DBG("Kernel channel %s disabled (fd: %d)", chan->channel->name, chan->fd);
 242
 243         return 0;
 244
 245 error:
 246         return ret;
 247 }
 248
 249 /*
 250  *  kernel_enable_channel
 251  *
 252  *  Enable a kernel channel.
 253  */
 254 int kernel_enable_channel(struct ltt_kernel_channel *chan)
 255 {
 256         int ret;
 257
 258         ret = kernctl_enable(chan->fd);
 259         if (ret < 0) {
 260                 perror("enable chan ioctl");
 261                 ret = errno;
 262                 goto error;
 263         }
 264
 265         chan->enabled = 1;
 266         DBG("Kernel channel %s enabled (fd: %d)", chan->channel->name, chan->fd);
 267
 268         return 0;
 269
 270 error:
 271         return ret;
 272 }
 273
 274 /*
 275  *  kernel_enable_event
 276  *
 277  *  Enable a kernel event.
 278  */
 279 int kernel_enable_event(struct ltt_kernel_event *event)
 280 {
 281         int ret;
 282
 283         ret = kernctl_enable(event->fd);
 284         if (ret < 0) {
 285                 perror("enable event ioctl");
 286                 if (errno == EEXIST) {
 287                         ret = -EEXIST;
 288                 }
 289                 goto error;
 290         }
 291
 292         event->enabled = 1;
 293         DBG("Kernel event %s enabled (fd: %d)", event->event->name, event->fd);
 294
 295         return 0;
 296
 297 error:
 298         return ret;
 299 }
 300
 301 /*
 302  *  kernel_disable_event
 303  *
 304  *  Disable a kernel event.
 305  */
 306 int kernel_disable_event(struct ltt_kernel_event *event)
 307 {
 308         int ret;
 309
 310         ret = kernctl_disable(event->fd);
 311         if (ret < 0) {
 312                 perror("disable event ioctl");
 313                 goto error;
 314         }
 315
 316         event->enabled = 0;
 317         DBG("Kernel event %s disabled (fd: %d)", event->event->name, event->fd);
 318
 319         return 0;
 320
 321 error:
 322         return ret;
 323 }
 324
 325 /*
 326  *  kernel_open_metadata
 327  *
 328  *  Create kernel metadata, open from the kernel tracer and add it to the
 329  *  kernel session.
 330  */
 331 int kernel_open_metadata(struct ltt_kernel_session *session, char *path)
 332 {
 333         int ret;
 334         struct ltt_kernel_metadata *lkm;
 335
 336         /* Allocate kernel metadata */
 337         lkm = trace_create_kernel_metadata(path);
 338         if (lkm == NULL) {
 339                 goto error;
 340         }
 341
 342         /* Kernel tracer metadata creation */
 343         ret = kernctl_open_metadata(session->fd, &lkm->conf->attr);
 344         if (ret < 0) {
 345                 goto error;
 346         }
 347
 348         lkm->fd = ret;
 349         /* Prevent fd duplication after execlp() */
 350         ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC);
 351         if (ret < 0) {
 352                 perror("fcntl session fd");
 353         }
 354
 355         session->metadata = lkm;
 356
 357         DBG("Kernel metadata opened (fd: %d and path: %s)", lkm->fd, lkm->pathname);
 358
 359         return 0;
 360
 361 error:
 362         return -1;
 363 }
 364
 365 /*
 366  *  kernel_start_session
 367  *
 368  *  Start tracing session.
 369  */
 370 int kernel_start_session(struct ltt_kernel_session *session)
 371 {
 372         int ret;
 373
 374         ret = kernctl_start_session(session->fd);
 375         if (ret < 0) {
 376                 perror("ioctl start session");
 377                 goto error;
 378         }
 379
 380         DBG("Kernel session started");
 381
 382         return 0;
 383
 384 error:
 385         return ret;
 386 }
 387
 388 /*
 389  *  kernel_wait_quiescent
 390  *
 391  *  Make a kernel wait to make sure in-flight probe have completed.
 392  */
 393 void kernel_wait_quiescent(int fd)
 394 {
 395         int ret;
 396
 397         DBG("Kernel quiescent wait on %d", fd);
 398
 399         ret = kernctl_wait_quiescent(fd);
 400         if (ret < 0) {
 401                 perror("wait quiescent ioctl");
 402                 ERR("Kernel quiescent wait failed");
 403         }
 404 }
 405
 406 /*
 407  *  kernel_metadata_flush_buffer
 408  *
 409  *  Force flush buffer of metadata.
 410  */
 411 int kernel_metadata_flush_buffer(int fd)
 412 {
 413         int ret;
 414
 415         ret = kernctl_buffer_flush(fd);
 416         if (ret < 0) {
 417                 ERR("Fail to flush metadata buffers %d (ret: %d", fd, ret);
 418         }
 419
 420         return 0;
 421 }
 422
 423 /*
 424  *  kernel_flush_buffer
 425  *
 426  *  Force flush buffer for channel.
 427  */
 428 int kernel_flush_buffer(struct ltt_kernel_channel *channel)
 429 {
 430         int ret;
 431         struct ltt_kernel_stream *stream;
 432
 433         DBG("Flush buffer for channel %s", channel->channel->name);
 434
 435         cds_list_for_each_entry(stream, &channel->stream_list.head, list) {
 436                 DBG("Flushing channel stream %d", stream->fd);
 437                 ret = kernctl_buffer_flush(stream->fd);
 438                 if (ret < 0) {
 439                         perror("ioctl");
 440                         ERR("Fail to flush buffer for stream %d (ret: %d)",
 441                                         stream->fd, ret);
 442                 }
 443         }
 444
 445         return 0;
 446 }
 447
 448 /*
 449  *  kernel_stop_session
 450  *
 451  *  Stop tracing session.
 452  */
 453 int kernel_stop_session(struct ltt_kernel_session *session)
 454 {
 455         int ret;
 456
 457         ret = kernctl_stop_session(session->fd);
 458         if (ret < 0) {
 459                 goto error;
 460         }
 461
 462         DBG("Kernel session stopped");
 463
 464         return 0;
 465
 466 error:
 467         return ret;
 468 }
 469
 470 /*
 471  *  kernel_open_channel_stream
 472  *
 473  *  Open stream of channel, register it to the kernel tracer and add it
 474  *  to the stream list of the channel.
 475  *
 476  *  Return the number of created stream. Else, a negative value.
 477  */
 478 int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
 479 {
 480         int ret;
 481         struct ltt_kernel_stream *lks;
 482
 483         while ((ret = kernctl_create_stream(channel->fd)) > 0) {
 484                 lks = trace_create_kernel_stream();
 485                 if (lks == NULL) {
 486                         close(ret);
 487                         goto error;
 488                 }
 489
 490                 lks->fd = ret;
 491                 /* Prevent fd duplication after execlp() */
 492                 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
 493                 if (ret < 0) {
 494                         perror("fcntl session fd");
 495                 }
 496
 497                 ret = asprintf(&lks->pathname, "%s/%s_%d",
 498                                 channel->pathname, channel->channel->name, channel->stream_count);
 499                 if (ret < 0) {
 500                         perror("asprintf kernel create stream");
 501                         goto error;
 502                 }
 503
 504                 /* Add stream to channe stream list */
 505                 cds_list_add(&lks->list, &channel->stream_list.head);
 506                 channel->stream_count++;
 507
 508                 DBG("Kernel stream %d created (fd: %d, state: %d, path: %s)",
 509                                 channel->stream_count, lks->fd, lks->state, lks->pathname);
 510         }
 511
 512         return channel->stream_count;
 513
 514 error:
 515         return -1;
 516 }
 517
 518 /*
 519  *  kernel_open_metadata_stream
 520  *
 521  *  Open the metadata stream and set it to the kernel session.
 522  */
 523 int kernel_open_metadata_stream(struct ltt_kernel_session *session)
 524 {
 525         int ret;
 526
 527         ret = kernctl_create_stream(session->metadata->fd);
 528         if (ret < 0) {
 529                 perror("kernel create metadata stream");
 530                 goto error;
 531         }
 532
 533         DBG("Kernel metadata stream created (fd: %d)", ret);
 534         session->metadata_stream_fd = ret;
 535         /* Prevent fd duplication after execlp() */
 536         ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC);
 537         if (ret < 0) {
 538                 perror("fcntl session fd");
 539         }
 540
 541         return 0;
 542
 543 error:
 544         return -1;
 545 }
 546
 547 /*
 548  *  kernel_list_events
 549  *
 550  *  Get the event list from the kernel tracer and return that list in the CTF
 551  *  format.
 552  */
 553 ssize_t kernel_list_events(int tracer_fd, char **list)
 554 {
 555         int fd;
 556         char *buf, *line = NULL;
 557         size_t nb, nbmem, total = 0;
 558         ssize_t size;
 559         FILE *fp;
 560
 561         fd = kernctl_tracepoint_list(tracer_fd);
 562         if (fd < 0) {
 563                 perror("kernel tracepoint list");
 564                 goto error;
 565         }
 566
 567         fp = fdopen(fd, "r");
 568         if (fp == NULL) {
 569                 perror("kernel tracepoint list fdopen");
 570                 goto error;
 571         }
 572
 573         /*
 574          * Init memory size counter
 575          * See kernel-ctl.h for explanation of this value
 576          */
 577         nbmem = KERNEL_EVENT_LIST_SIZE;
 578         buf = malloc(nbmem);
 579
 580         while ((size = getline(&line, &nb, fp)) != -1) {
 581                 if (total + size > nbmem) {
 582                         DBG("Reallocating event list from %zd to %zd bytes", nbmem,
 583                                         total + size + KERNEL_EVENT_LIST_SIZE);
 584                         /* Adding the default size again */
 585                         nbmem = total + size + KERNEL_EVENT_LIST_SIZE;
 586                         buf = realloc(buf, nbmem);
 587                         if (buf == NULL) {
 588                                 perror("realloc list events");
 589                                 goto error;
 590                         }
 591                 }
 592                 memcpy(buf + total, line, size);
 593                 total += size;
 594         }
 595
 596         *list = buf;
 597
 598         DBG("Kernel list events done");
 599
 600         return total;
 601
 602 error:
 603         return -1;
 604 }