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