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 <lttng-kernel-ctl.h>
  28 #include <lttngerr.h>
  29
  30 #include "kernel-ctl.h"
  31
  32 /*
  33  * Add context on a kernel channel.
  34  */
  35 int kernel_add_channel_context(struct ltt_kernel_channel *chan,
  36                 struct lttng_kernel_context *ctx)
  37 {
  38         int ret;
  39
  40         DBG("Adding context to channel %s", chan->channel->name);
  41         ret = kernctl_add_context(chan->fd, ctx);
  42         if (ret < 0) {
  43                 if (errno != EEXIST) {
  44                         perror("add context ioctl");
  45                 } else {
  46                         /* If EEXIST, we just ignore the error */
  47                         ret = 0;
  48                 }
  49                 goto error;
  50         }
  51
  52         chan->ctx = malloc(sizeof(struct lttng_kernel_context));
  53         if (chan->ctx == NULL) {
  54                 perror("malloc event context");
  55                 goto error;
  56         }
  57
  58         memcpy(chan->ctx, ctx, sizeof(struct lttng_kernel_context));
  59
  60         return 0;
  61
  62 error:
  63         return ret;
  64 }
  65
  66 /*
  67  * Add context on a kernel event.
  68  */
  69 int kernel_add_event_context(struct ltt_kernel_event *event,
  70                 struct lttng_kernel_context *ctx)
  71 {
  72         int ret;
  73
  74         DBG("Adding context to event %s", event->event->name);
  75         ret = kernctl_add_context(event->fd, ctx);
  76         if (ret < 0) {
  77                 perror("add context ioctl");
  78                 goto error;
  79         }
  80
  81         event->ctx = malloc(sizeof(struct lttng_kernel_context));
  82         if (event->ctx == NULL) {
  83                 perror("malloc event context");
  84                 goto error;
  85         }
  86
  87         memcpy(event->ctx, ctx, sizeof(struct lttng_kernel_context));
  88
  89         return 0;
  90
  91 error:
  92         return ret;
  93 }
  94
  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_kernel_create_session(session->path);
 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  * Create a kernel channel, register it to the kernel tracer and add it to the
 138  * kernel session.
 139  */
 140 int kernel_create_channel(struct ltt_kernel_session *session,
 141                 struct lttng_channel *chan, char *path)
 142 {
 143         int ret;
 144         struct ltt_kernel_channel *lkc;
 145
 146         /* Allocate kernel channel */
 147         lkc = trace_kernel_create_channel(chan, path);
 148         if (lkc == NULL) {
 149                 goto error;
 150         }
 151
 152         /* Kernel tracer channel creation */
 153         ret = kernctl_create_channel(session->fd, &lkc->channel->attr);
 154         if (ret < 0) {
 155                 perror("ioctl kernel create channel");
 156                 goto error;
 157         }
 158
 159         /* Setup the channel fd */
 160         lkc->fd = ret;
 161         /* Prevent fd duplication after execlp() */
 162         ret = fcntl(lkc->fd, F_SETFD, FD_CLOEXEC);
 163         if (ret < 0) {
 164                 perror("fcntl session fd");
 165         }
 166
 167         /* Add channel to session */
 168         cds_list_add(&lkc->list, &session->channel_list.head);
 169         session->channel_count++;
 170
 171         DBG("Kernel channel %s created (fd: %d and path: %s)",
 172                         lkc->channel->name, lkc->fd, lkc->pathname);
 173
 174         return 0;
 175
 176 error:
 177         return -1;
 178 }
 179
 180 /*
 181  * Create a kernel event, enable it to the kernel tracer and add it to the
 182  * channel event list of the kernel session.
 183  */
 184 int kernel_create_event(struct lttng_event *ev,
 185                 struct ltt_kernel_channel *channel)
 186 {
 187         int ret;
 188         struct ltt_kernel_event *event;
 189
 190         event = trace_kernel_create_event(ev);
 191         if (event == NULL) {
 192                 goto error;
 193         }
 194
 195         ret = kernctl_create_event(channel->fd, event->event);
 196         if (ret < 0) {
 197                 perror("create event ioctl");
 198                 goto free_event;
 199         }
 200
 201         event->fd = ret;
 202         /* Prevent fd duplication after execlp() */
 203         ret = fcntl(event->fd, F_SETFD, FD_CLOEXEC);
 204         if (ret < 0) {
 205                 perror("fcntl session fd");
 206         }
 207
 208         /* Add event to event list */
 209         cds_list_add(&event->list, &channel->events_list.head);
 210         channel->event_count++;
 211
 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  * Disable a kernel channel.
 224  */
 225 int kernel_disable_channel(struct ltt_kernel_channel *chan)
 226 {
 227         int ret;
 228
 229         ret = kernctl_disable(chan->fd);
 230         if (ret < 0) {
 231                 perror("disable chan ioctl");
 232                 ret = errno;
 233                 goto error;
 234         }
 235
 236         chan->enabled = 0;
 237         DBG("Kernel channel %s disabled (fd: %d)", chan->channel->name, chan->fd);
 238
 239         return 0;
 240
 241 error:
 242         return ret;
 243 }
 244
 245 /*
 246  * Enable a kernel channel.
 247  */
 248 int kernel_enable_channel(struct ltt_kernel_channel *chan)
 249 {
 250         int ret;
 251
 252         ret = kernctl_enable(chan->fd);
 253         if (ret < 0) {
 254                 perror("enable chan ioctl");
 255                 ret = errno;
 256                 goto error;
 257         }
 258
 259         chan->enabled = 1;
 260         DBG("Kernel channel %s enabled (fd: %d)", chan->channel->name, chan->fd);
 261
 262         return 0;
 263
 264 error:
 265         return ret;
 266 }
 267
 268 /*
 269  * Enable a kernel event.
 270  */
 271 int kernel_enable_event(struct ltt_kernel_event *event)
 272 {
 273         int ret;
 274
 275         ret = kernctl_enable(event->fd);
 276         if (ret < 0) {
 277                 perror("enable event ioctl");
 278                 if (errno == EEXIST) {
 279                         ret = -EEXIST;
 280                 }
 281                 goto error;
 282         }
 283
 284         event->enabled = 1;
 285         DBG("Kernel event %s enabled (fd: %d)", event->event->name, event->fd);
 286
 287         return 0;
 288
 289 error:
 290         return ret;
 291 }
 292
 293 /*
 294  * Disable a kernel event.
 295  */
 296 int kernel_disable_event(struct ltt_kernel_event *event)
 297 {
 298         int ret;
 299
 300         ret = kernctl_disable(event->fd);
 301         if (ret < 0) {
 302                 perror("disable event ioctl");
 303                 goto error;
 304         }
 305
 306         event->enabled = 0;
 307         DBG("Kernel event %s disabled (fd: %d)", event->event->name, event->fd);
 308
 309         return 0;
 310
 311 error:
 312         return ret;
 313 }
 314
 315 /*
 316  * Create kernel metadata, open from the kernel tracer and add it to the
 317  * kernel session.
 318  */
 319 int kernel_open_metadata(struct ltt_kernel_session *session, char *path)
 320 {
 321         int ret;
 322         struct ltt_kernel_metadata *lkm;
 323
 324         /* Allocate kernel metadata */
 325         lkm = trace_kernel_create_metadata(path);
 326         if (lkm == NULL) {
 327                 goto error;
 328         }
 329
 330         /* Kernel tracer metadata creation */
 331         ret = kernctl_open_metadata(session->fd, &lkm->conf->attr);
 332         if (ret < 0) {
 333                 goto error;
 334         }
 335
 336         lkm->fd = ret;
 337         /* Prevent fd duplication after execlp() */
 338         ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC);
 339         if (ret < 0) {
 340                 perror("fcntl session fd");
 341         }
 342
 343         session->metadata = lkm;
 344
 345         DBG("Kernel metadata opened (fd: %d and path: %s)", lkm->fd, lkm->pathname);
 346
 347         return 0;
 348
 349 error:
 350         return -1;
 351 }
 352
 353 /*
 354  * Start tracing session.
 355  */
 356 int kernel_start_session(struct ltt_kernel_session *session)
 357 {
 358         int ret;
 359
 360         ret = kernctl_start_session(session->fd);
 361         if (ret < 0) {
 362                 perror("ioctl start session");
 363                 goto error;
 364         }
 365
 366         DBG("Kernel session started");
 367
 368         return 0;
 369
 370 error:
 371         return ret;
 372 }
 373
 374 /*
 375  * Make a kernel wait to make sure in-flight probe have completed.
 376  */
 377 void kernel_wait_quiescent(int fd)
 378 {
 379         int ret;
 380
 381         DBG("Kernel quiescent wait on %d", fd);
 382
 383         ret = kernctl_wait_quiescent(fd);
 384         if (ret < 0) {
 385                 perror("wait quiescent ioctl");
 386                 ERR("Kernel quiescent wait failed");
 387         }
 388 }
 389
 390 /*
 391  * Kernel calibrate
 392  */
 393 int kernel_calibrate(int fd, struct lttng_kernel_calibrate *calibrate)
 394 {
 395         int ret;
 396
 397         ret = kernctl_calibrate(fd, calibrate);
 398         if (ret < 0) {
 399                 perror("calibrate ioctl");
 400                 return -1;
 401         }
 402
 403         return 0;
 404 }
 405
 406
 407 /*
 408  *  Force flush buffer of metadata.
 409  */
 410 int kernel_metadata_flush_buffer(int fd)
 411 {
 412         int ret;
 413
 414         ret = kernctl_buffer_flush(fd);
 415         if (ret < 0) {
 416                 ERR("Fail to flush metadata buffers %d (ret: %d", fd, ret);
 417         }
 418
 419         return 0;
 420 }
 421
 422 /*
 423  * Force flush buffer for channel.
 424  */
 425 int kernel_flush_buffer(struct ltt_kernel_channel *channel)
 426 {
 427         int ret;
 428         struct ltt_kernel_stream *stream;
 429
 430         DBG("Flush buffer for channel %s", channel->channel->name);
 431
 432         cds_list_for_each_entry(stream, &channel->stream_list.head, list) {
 433                 DBG("Flushing channel stream %d", stream->fd);
 434                 ret = kernctl_buffer_flush(stream->fd);
 435                 if (ret < 0) {
 436                         perror("ioctl");
 437                         ERR("Fail to flush buffer for stream %d (ret: %d)",
 438                                         stream->fd, ret);
 439                 }
 440         }
 441
 442         return 0;
 443 }
 444
 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  * Open stream of channel, register it to the kernel tracer and add it
 467  * to the stream list of the channel.
 468  *
 469  * Return the number of created stream. Else, a negative value.
 470  */
 471 int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
 472 {
 473         int ret;
 474         struct ltt_kernel_stream *lks;
 475
 476         while ((ret = kernctl_create_stream(channel->fd)) > 0) {
 477                 lks = trace_kernel_create_stream();
 478                 if (lks == NULL) {
 479                         close(ret);
 480                         goto error;
 481                 }
 482
 483                 lks->fd = ret;
 484                 /* Prevent fd duplication after execlp() */
 485                 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
 486                 if (ret < 0) {
 487                         perror("fcntl session fd");
 488                 }
 489
 490                 ret = asprintf(&lks->pathname, "%s/%s_%d",
 491                                 channel->pathname, channel->channel->name, channel->stream_count);
 492                 if (ret < 0) {
 493                         perror("asprintf kernel create stream");
 494                         goto error;
 495                 }
 496
 497                 /* Add stream to channe stream list */
 498                 cds_list_add(&lks->list, &channel->stream_list.head);
 499                 channel->stream_count++;
 500
 501                 DBG("Kernel stream %d created (fd: %d, state: %d, path: %s)",
 502                                 channel->stream_count, lks->fd, lks->state, lks->pathname);
 503         }
 504
 505         return channel->stream_count;
 506
 507 error:
 508         return -1;
 509 }
 510
 511 /*
 512  * Open the metadata stream and set it to the kernel session.
 513  */
 514 int kernel_open_metadata_stream(struct ltt_kernel_session *session)
 515 {
 516         int ret;
 517
 518         ret = kernctl_create_stream(session->metadata->fd);
 519         if (ret < 0) {
 520                 perror("kernel create metadata stream");
 521                 goto error;
 522         }
 523
 524         DBG("Kernel metadata stream created (fd: %d)", ret);
 525         session->metadata_stream_fd = ret;
 526         /* Prevent fd duplication after execlp() */
 527         ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC);
 528         if (ret < 0) {
 529                 perror("fcntl session fd");
 530         }
 531
 532         return 0;
 533
 534 error:
 535         return -1;
 536 }
 537
 538 /*
 539  * Get the event list from the kernel tracer and return the number of elements.
 540  */
 541 ssize_t kernel_list_events(int tracer_fd, struct lttng_event **events)
 542 {
 543         int fd, pos;
 544         char *event;
 545         size_t nbmem, count = 0;
 546         ssize_t size;
 547         FILE *fp;
 548         struct lttng_event *elist;
 549
 550         fd = kernctl_tracepoint_list(tracer_fd);
 551         if (fd < 0) {
 552                 perror("kernel tracepoint list");
 553                 goto error;
 554         }
 555
 556         fp = fdopen(fd, "r");
 557         if (fp == NULL) {
 558                 perror("kernel tracepoint list fdopen");
 559                 goto error_fp;
 560         }
 561
 562         /*
 563          * Init memory size counter
 564          * See kernel-ctl.h for explanation of this value
 565          */
 566         nbmem = KERNEL_EVENT_LIST_SIZE;
 567         elist = malloc(sizeof(struct lttng_event) * nbmem);
 568
 569         while ((size = fscanf(fp, "event { name = %m[^;]; };%n\n", &event, &pos)) == 1) {
 570                 if (count > nbmem) {
 571                         DBG("Reallocating event list from %zu to %zu bytes", nbmem,
 572                                         nbmem + KERNEL_EVENT_LIST_SIZE);
 573                         /* Adding the default size again */
 574                         nbmem += KERNEL_EVENT_LIST_SIZE;
 575                         elist = realloc(elist, nbmem);
 576                         if (elist == NULL) {
 577                                 perror("realloc list events");
 578                                 count = -ENOMEM;
 579                                 goto end;
 580                         }
 581                 }
 582                 strncpy(elist[count].name, event, LTTNG_SYMBOL_NAME_LEN);
 583                 elist[count].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 584                 count++;
 585         }
 586
 587         *events = elist;
 588         DBG("Kernel list events done (%zu events)", count);
 589 end:
 590         fclose(fp);     /* closes both fp and fd */
 591         return count;
 592
 593 error_fp:
 594         close(fd);
 595 error:
 596         return -1;
 597 }