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         /*
 202          * LTTNG_KERNEL_SYSCALL event creation will return 0 on success. However
 203          * this FD must not be added to the event list.
 204          */
 205         if (ret == 0 && event->event->instrumentation == LTTNG_KERNEL_SYSCALL) {
 206                 DBG2("Kernel event syscall creation success");
 207                 goto end;
 208         }
 209
 210         event->fd = ret;
 211         /* Prevent fd duplication after execlp() */
 212         ret = fcntl(event->fd, F_SETFD, FD_CLOEXEC);
 213         if (ret < 0) {
 214                 perror("fcntl session fd");
 215         }
 216
 217         /* Add event to event list */
 218         cds_list_add(&event->list, &channel->events_list.head);
 219         channel->event_count++;
 220
 221         DBG("Event %s created (fd: %d)", ev->name, event->fd);
 222
 223 end:
 224         return 0;
 225
 226 free_event:
 227         free(event);
 228 error:
 229         return -1;
 230 }
 231
 232 /*
 233  * Disable a kernel channel.
 234  */
 235 int kernel_disable_channel(struct ltt_kernel_channel *chan)
 236 {
 237         int ret;
 238
 239         ret = kernctl_disable(chan->fd);
 240         if (ret < 0) {
 241                 perror("disable chan ioctl");
 242                 ret = errno;
 243                 goto error;
 244         }
 245
 246         chan->enabled = 0;
 247         DBG("Kernel channel %s disabled (fd: %d)", chan->channel->name, chan->fd);
 248
 249         return 0;
 250
 251 error:
 252         return ret;
 253 }
 254
 255 /*
 256  * Enable a kernel channel.
 257  */
 258 int kernel_enable_channel(struct ltt_kernel_channel *chan)
 259 {
 260         int ret;
 261
 262         ret = kernctl_enable(chan->fd);
 263         if (ret < 0 && errno != EEXIST) {
 264                 perror("Enable kernel chan");
 265                 goto error;
 266         }
 267
 268         chan->enabled = 1;
 269         DBG("Kernel channel %s enabled (fd: %d)", chan->channel->name, chan->fd);
 270
 271         return 0;
 272
 273 error:
 274         return ret;
 275 }
 276
 277 /*
 278  * Enable a kernel event.
 279  */
 280 int kernel_enable_event(struct ltt_kernel_event *event)
 281 {
 282         int ret;
 283
 284         ret = kernctl_enable(event->fd);
 285         if (ret < 0 && errno != EEXIST) {
 286                 perror("enable kernel event");
 287                 goto error;
 288         }
 289
 290         event->enabled = 1;
 291         DBG("Kernel event %s enabled (fd: %d)", event->event->name, event->fd);
 292
 293         return 0;
 294
 295 error:
 296         return ret;
 297 }
 298
 299 /*
 300  * Disable a kernel event.
 301  */
 302 int kernel_disable_event(struct ltt_kernel_event *event)
 303 {
 304         int ret;
 305
 306         ret = kernctl_disable(event->fd);
 307         if (ret < 0 && errno != EEXIST) {
 308                 perror("disable kernel event");
 309                 goto error;
 310         }
 311
 312         event->enabled = 0;
 313         DBG("Kernel event %s disabled (fd: %d)", event->event->name, event->fd);
 314
 315         return 0;
 316
 317 error:
 318         return ret;
 319 }
 320
 321 /*
 322  * Create kernel metadata, open from the kernel tracer and add it to the
 323  * kernel session.
 324  */
 325 int kernel_open_metadata(struct ltt_kernel_session *session, char *path)
 326 {
 327         int ret;
 328         struct ltt_kernel_metadata *lkm;
 329
 330         /* Allocate kernel metadata */
 331         lkm = trace_kernel_create_metadata(path);
 332         if (lkm == NULL) {
 333                 goto error;
 334         }
 335
 336         /* Kernel tracer metadata creation */
 337         ret = kernctl_open_metadata(session->fd, &lkm->conf->attr);
 338         if (ret < 0) {
 339                 goto error;
 340         }
 341
 342         lkm->fd = ret;
 343         /* Prevent fd duplication after execlp() */
 344         ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC);
 345         if (ret < 0) {
 346                 perror("fcntl session fd");
 347         }
 348
 349         session->metadata = lkm;
 350
 351         DBG("Kernel metadata opened (fd: %d and path: %s)", lkm->fd, lkm->pathname);
 352
 353         return 0;
 354
 355 error:
 356         return -1;
 357 }
 358
 359 /*
 360  * Start tracing session.
 361  */
 362 int kernel_start_session(struct ltt_kernel_session *session)
 363 {
 364         int ret;
 365
 366         ret = kernctl_start_session(session->fd);
 367         if (ret < 0) {
 368                 perror("ioctl start session");
 369                 goto error;
 370         }
 371
 372         DBG("Kernel session started");
 373
 374         return 0;
 375
 376 error:
 377         return ret;
 378 }
 379
 380 /*
 381  * Make a kernel wait to make sure in-flight probe have completed.
 382  */
 383 void kernel_wait_quiescent(int fd)
 384 {
 385         int ret;
 386
 387         DBG("Kernel quiescent wait on %d", fd);
 388
 389         ret = kernctl_wait_quiescent(fd);
 390         if (ret < 0) {
 391                 perror("wait quiescent ioctl");
 392                 ERR("Kernel quiescent wait failed");
 393         }
 394 }
 395
 396 /*
 397  * Kernel calibrate
 398  */
 399 int kernel_calibrate(int fd, struct lttng_kernel_calibrate *calibrate)
 400 {
 401         int ret;
 402
 403         ret = kernctl_calibrate(fd, calibrate);
 404         if (ret < 0) {
 405                 perror("calibrate ioctl");
 406                 return -1;
 407         }
 408
 409         return 0;
 410 }
 411
 412
 413 /*
 414  *  Force flush buffer of metadata.
 415  */
 416 int kernel_metadata_flush_buffer(int fd)
 417 {
 418         int ret;
 419
 420         ret = kernctl_buffer_flush(fd);
 421         if (ret < 0) {
 422                 ERR("Fail to flush metadata buffers %d (ret: %d", fd, ret);
 423         }
 424
 425         return 0;
 426 }
 427
 428 /*
 429  * Force flush buffer for channel.
 430  */
 431 int kernel_flush_buffer(struct ltt_kernel_channel *channel)
 432 {
 433         int ret;
 434         struct ltt_kernel_stream *stream;
 435
 436         DBG("Flush buffer for channel %s", channel->channel->name);
 437
 438         cds_list_for_each_entry(stream, &channel->stream_list.head, list) {
 439                 DBG("Flushing channel stream %d", stream->fd);
 440                 ret = kernctl_buffer_flush(stream->fd);
 441                 if (ret < 0) {
 442                         perror("ioctl");
 443                         ERR("Fail to flush buffer for stream %d (ret: %d)",
 444                                         stream->fd, ret);
 445                 }
 446         }
 447
 448         return 0;
 449 }
 450
 451 /*
 452  * Stop tracing session.
 453  */
 454 int kernel_stop_session(struct ltt_kernel_session *session)
 455 {
 456         int ret;
 457
 458         ret = kernctl_stop_session(session->fd);
 459         if (ret < 0) {
 460                 goto error;
 461         }
 462
 463         DBG("Kernel session stopped");
 464
 465         return 0;
 466
 467 error:
 468         return ret;
 469 }
 470
 471 /*
 472  * Open stream of channel, register it to the kernel tracer and add it
 473  * to the stream list of the channel.
 474  *
 475  * Return the number of created stream. Else, a negative value.
 476  */
 477 int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
 478 {
 479         int ret;
 480         struct ltt_kernel_stream *lks;
 481
 482         while ((ret = kernctl_create_stream(channel->fd)) > 0) {
 483                 lks = trace_kernel_create_stream();
 484                 if (lks == NULL) {
 485                         close(ret);
 486                         goto error;
 487                 }
 488
 489                 lks->fd = ret;
 490                 /* Prevent fd duplication after execlp() */
 491                 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
 492                 if (ret < 0) {
 493                         perror("fcntl session fd");
 494                 }
 495
 496                 ret = asprintf(&lks->pathname, "%s/%s_%d",
 497                                 channel->pathname, channel->channel->name, channel->stream_count);
 498                 if (ret < 0) {
 499                         perror("asprintf kernel create stream");
 500                         goto error;
 501                 }
 502
 503                 /* Add stream to channe stream list */
 504                 cds_list_add(&lks->list, &channel->stream_list.head);
 505                 channel->stream_count++;
 506
 507                 DBG("Kernel stream %d created (fd: %d, state: %d, path: %s)",
 508                                 channel->stream_count, lks->fd, lks->state, lks->pathname);
 509         }
 510
 511         return channel->stream_count;
 512
 513 error:
 514         return -1;
 515 }
 516
 517 /*
 518  * Open the metadata stream and set it to the kernel session.
 519  */
 520 int kernel_open_metadata_stream(struct ltt_kernel_session *session)
 521 {
 522         int ret;
 523
 524         ret = kernctl_create_stream(session->metadata->fd);
 525         if (ret < 0) {
 526                 perror("kernel create metadata stream");
 527                 goto error;
 528         }
 529
 530         DBG("Kernel metadata stream created (fd: %d)", ret);
 531         session->metadata_stream_fd = ret;
 532         /* Prevent fd duplication after execlp() */
 533         ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC);
 534         if (ret < 0) {
 535                 perror("fcntl session fd");
 536         }
 537
 538         return 0;
 539
 540 error:
 541         return -1;
 542 }
 543
 544 /*
 545  * Get the event list from the kernel tracer and return the number of elements.
 546  */
 547 ssize_t kernel_list_events(int tracer_fd, struct lttng_event **events)
 548 {
 549         int fd, pos;
 550         char *event;
 551         size_t nbmem, count = 0;
 552         ssize_t size;
 553         FILE *fp;
 554         struct lttng_event *elist;
 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_fp;
 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         elist = malloc(sizeof(struct lttng_event) * nbmem);
 574
 575         while ((size = fscanf(fp, "event { name = %m[^;]; };%n\n", &event, &pos)) == 1) {
 576                 if (count > nbmem) {
 577                         DBG("Reallocating event list from %zu to %zu bytes", nbmem,
 578                                         nbmem + KERNEL_EVENT_LIST_SIZE);
 579                         /* Adding the default size again */
 580                         nbmem += KERNEL_EVENT_LIST_SIZE;
 581                         elist = realloc(elist, nbmem);
 582                         if (elist == NULL) {
 583                                 perror("realloc list events");
 584                                 count = -ENOMEM;
 585                                 goto end;
 586                         }
 587                 }
 588                 strncpy(elist[count].name, event, LTTNG_SYMBOL_NAME_LEN);
 589                 elist[count].name[LTTNG_SYMBOL_NAME_LEN - 1] = '\0';
 590                 count++;
 591         }
 592
 593         *events = elist;
 594         DBG("Kernel list events done (%zu events)", count);
 595 end:
 596         fclose(fp);     /* closes both fp and fd */
 597         return count;
 598
 599 error_fp:
 600         close(fd);
 601 error:
 602         return -1;
 603 }