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 "ltt-sessiond.h"
  29 #include "libkernelctl.h"
  30 #include "kernel-ctl.h"
  31
  32 /*
  33  *  kernel_create_session
  34  *
  35  *  Create a new kernel session, register it to the kernel tracer and add it to
  36  *  the session daemon session.
  37  */
  38 int kernel_create_session(struct ltt_session *session, int tracer_fd)
  39 {
  40         int ret;
  41         struct ltt_kernel_session *lks;
  42
  43         /* Allocate data structure */
  44         lks = trace_create_kernel_session();
  45         if (lks == NULL) {
  46                 ret = -1;
  47                 goto error;
  48         }
  49
  50         /* Kernel tracer session creation */
  51         ret = kernctl_create_session(tracer_fd);
  52         if (ret < 0) {
  53                 perror("ioctl kernel create session");
  54                 goto error;
  55         }
  56
  57         lks->fd = ret;
  58         /* Prevent fd duplication after execlp() */
  59         ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
  60         if (ret < 0) {
  61                 perror("fcntl session fd");
  62         }
  63
  64         lks->kconsumer_fds_sent = 0;
  65         session->kernel_session = lks;
  66         session->kern_session_count++;
  67
  68         DBG("Kernel session created (fd: %d)", lks->fd);
  69
  70         return 0;
  71
  72 error:
  73         return ret;
  74 }
  75
  76 /*
  77  *  kernel_create_channel
  78  *
  79  *  Create a kernel channel, register it to the kernel tracer and add it to the
  80  *  kernel session.
  81  */
  82 int kernel_create_channel(struct ltt_kernel_session *session, struct lttng_channel *chan)
  83 {
  84         int ret;
  85         struct ltt_kernel_channel *lkc;
  86
  87         /* Allocate kernel channel */
  88         lkc = trace_create_kernel_channel(chan);
  89         if (lkc == NULL) {
  90                 goto error;
  91         }
  92
  93         /* Kernel tracer channel creation */
  94         ret = kernctl_create_channel(session->fd, &lkc->channel->attr);
  95         if (ret < 0) {
  96                 perror("ioctl kernel create channel");
  97                 goto error;
  98         }
  99
 100         /* Setup the channel fd */
 101         lkc->fd = ret;
 102         /* Prevent fd duplication after execlp() */
 103         ret = fcntl(lkc->fd, F_SETFD, FD_CLOEXEC);
 104         if (ret < 0) {
 105                 perror("fcntl session fd");
 106         }
 107
 108         /* Add channel to session */
 109         cds_list_add(&lkc->list, &session->channel_list.head);
 110         session->channel_count++;
 111
 112         DBG("Kernel channel %s created (fd: %d and path: %s)",
 113                         lkc->channel->name, lkc->fd, lkc->pathname);
 114
 115         return 0;
 116
 117 error:
 118         return -1;
 119 }
 120
 121 /*
 122  *  kernel_create_event
 123  *
 124  *  Create a kernel event, enable it to the kernel tracer and add it to the
 125  *  channel event list of the kernel session.
 126  */
 127 int kernel_create_event(struct ltt_kernel_channel *channel, struct lttng_event *ev)
 128 {
 129         int ret;
 130         struct ltt_kernel_event *event;
 131
 132         event = trace_create_kernel_event(ev);
 133         if (event == NULL) {
 134                 goto error;
 135         }
 136
 137         ret = kernctl_create_event(channel->fd, event->event);
 138         if (ret < 0) {
 139                 perror("create event ioctl");
 140                 goto free_event;
 141         }
 142
 143         event->fd = ret;
 144         event->enabled = 1;
 145         /* Prevent fd duplication after execlp() */
 146         ret = fcntl(event->fd, F_SETFD, FD_CLOEXEC);
 147         if (ret < 0) {
 148                 perror("fcntl session fd");
 149         }
 150
 151         /* Add event to event list */
 152         cds_list_add(&event->list, &channel->events_list.head);
 153         DBG("Event %s created (fd: %d)", ev->name, event->fd);
 154
 155         return 0;
 156
 157 free_event:
 158         free(event);
 159 error:
 160         return -1;
 161 }
 162
 163 /*
 164  *  kernel_disable_event
 165  *
 166  *  Disable a kernel event for a specific channel.
 167  */
 168 int kernel_disable_event(char *event_name, struct ltt_kernel_channel *channel)
 169 {
 170         int ret;
 171         struct ltt_kernel_event *iter;
 172
 173         cds_list_for_each_entry(iter, &channel->events_list.head, list) {
 174                 if (strcmp(iter->event->name, event_name) == 0) {
 175                         ret = kernctl_disable(iter->fd);
 176                         if (ret < 0) {
 177                                 perror("disable event ioctl");
 178                                 goto error;
 179                         }
 180
 181                         iter->enabled = 0;
 182                         DBG("Kernel event %s disabled (fd: %d)", iter->event->name, iter->fd);
 183                         break;
 184                 }
 185         }
 186
 187         return 0;
 188
 189 error:
 190         return -1;
 191 }
 192
 193 /*
 194  *  kernel_open_metadata
 195  *
 196  *  Create kernel metadata, open from the kernel tracer and add it to the
 197  *  kernel session.
 198  */
 199 int kernel_open_metadata(struct ltt_kernel_session *session)
 200 {
 201         int ret;
 202         struct ltt_kernel_metadata *lkm;
 203
 204         /* Allocate kernel metadata */
 205         lkm = trace_create_kernel_metadata();
 206         if (lkm == NULL) {
 207                 goto error;
 208         }
 209
 210         /* Kernel tracer metadata creation */
 211         ret = kernctl_open_metadata(session->fd, &lkm->conf->attr);
 212         if (ret < 0) {
 213                 goto error;
 214         }
 215
 216         lkm->fd = ret;
 217         /* Prevent fd duplication after execlp() */
 218         ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC);
 219         if (ret < 0) {
 220                 perror("fcntl session fd");
 221         }
 222
 223         session->metadata = lkm;
 224
 225         DBG("Kernel metadata opened (fd: %d and path: %s)", lkm->fd, lkm->pathname);
 226
 227         return 0;
 228
 229 error:
 230         return -1;
 231 }
 232
 233 /*
 234  *  kernel_start_session
 235  *
 236  *  Start tracing session.
 237  */
 238 int kernel_start_session(struct ltt_kernel_session *session)
 239 {
 240         int ret;
 241
 242         ret = kernctl_start_session(session->fd);
 243         if (ret < 0) {
 244                 perror("ioctl start session");
 245                 goto error;
 246         }
 247
 248         DBG("Kernel session started");
 249
 250         return 0;
 251
 252 error:
 253         return ret;
 254 }
 255
 256 /*
 257  *  kernel_wait_quiescent
 258  *
 259  *  Make a kernel wait to make sure in-flight probe have completed.
 260  */
 261 void kernel_wait_quiescent(int fd)
 262 {
 263         int ret;
 264
 265         DBG("Kernel quiescent wait on %d", fd);
 266
 267         ret = kernctl_wait_quiescent(fd);
 268         if (ret < 0) {
 269                 perror("wait quiescent ioctl");
 270                 ERR("Kernel quiescent wait failed");
 271         }
 272 }
 273
 274 /*
 275  *  kernel_metadata_flush_buffer
 276  *
 277  *  Force flush buffer of metadata.
 278  */
 279 int kernel_metadata_flush_buffer(int fd)
 280 {
 281         int ret;
 282
 283         ret = kernctl_buffer_flush(fd);
 284         if (ret < 0) {
 285                 ERR("Fail to flush metadata buffers %d (ret: %d", fd, ret);
 286         }
 287
 288         return 0;
 289 }
 290
 291 /*
 292  *  kernel_flush_buffer
 293  *
 294  *  Force flush buffer for channel.
 295  */
 296 int kernel_flush_buffer(struct ltt_kernel_channel *channel)
 297 {
 298         int ret;
 299         struct ltt_kernel_stream *stream;
 300
 301         DBG("Flush buffer for channel %s", channel->channel->name);
 302
 303         cds_list_for_each_entry(stream, &channel->stream_list.head, list) {
 304                 DBG("Flushing channel stream %d", stream->fd);
 305                 ret = kernctl_buffer_flush(stream->fd);
 306                 if (ret < 0) {
 307                         perror("ioctl");
 308                         ERR("Fail to flush buffer for stream %d (ret: %d)",
 309                                         stream->fd, ret);
 310                 }
 311         }
 312
 313         return 0;
 314 }
 315
 316 /*
 317  *  kernel_stop_session
 318  *
 319  *  Stop tracing session.
 320  */
 321 int kernel_stop_session(struct ltt_kernel_session *session)
 322 {
 323         int ret;
 324
 325         ret = kernctl_stop_session(session->fd);
 326         if (ret < 0) {
 327                 goto error;
 328         }
 329
 330         DBG("Kernel session stopped");
 331
 332         return 0;
 333
 334 error:
 335         return ret;
 336 }
 337
 338 /*
 339  *  kernel_open_channel_stream
 340  *
 341  *  Open stream of channel, register it to the kernel tracer and add it
 342  *  to the stream list of the channel.
 343  *
 344  *  Return the number of created stream. Else, a negative value.
 345  */
 346 int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
 347 {
 348         int ret;
 349         struct ltt_kernel_stream *lks;
 350
 351         while ((ret = kernctl_create_stream(channel->fd)) > 0) {
 352                 lks = trace_create_kernel_stream();
 353                 if (lks == NULL) {
 354                         close(ret);
 355                         goto error;
 356                 }
 357
 358                 lks->fd = ret;
 359                 /* Prevent fd duplication after execlp() */
 360                 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
 361                 if (ret < 0) {
 362                         perror("fcntl session fd");
 363                 }
 364
 365                 ret = asprintf(&lks->pathname, "%s/trace_%d",
 366                                 channel->pathname, channel->stream_count);
 367                 if (ret < 0) {
 368                         perror("asprintf kernel create stream");
 369                         goto error;
 370                 }
 371
 372                 /* Add stream to channe stream list */
 373                 cds_list_add(&lks->list, &channel->stream_list.head);
 374                 channel->stream_count++;
 375
 376                 DBG("Kernel stream %d created (fd: %d, state: %d, path: %s)",
 377                                 channel->stream_count, lks->fd, lks->state, lks->pathname);
 378         }
 379
 380         return channel->stream_count;
 381
 382 error:
 383         return -1;
 384 }
 385
 386 /*
 387  *  kernel_open_metadata_stream
 388  *
 389  *  Open the metadata stream and set it to the kernel session.
 390  */
 391 int kernel_open_metadata_stream(struct ltt_kernel_session *session)
 392 {
 393         int ret;
 394
 395         ret = kernctl_create_stream(session->metadata->fd);
 396         if (ret < 0) {
 397                 perror("kernel create metadata stream");
 398                 goto error;
 399         }
 400
 401         DBG("Kernel metadata stream created (fd: %d)", ret);
 402         session->metadata_stream_fd = ret;
 403         /* Prevent fd duplication after execlp() */
 404         ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC);
 405         if (ret < 0) {
 406                 perror("fcntl session fd");
 407         }
 408
 409         return 0;
 410
 411 error:
 412         return -1;
 413 }
 414
 415 /*
 416  *  kernel_list_events
 417  *
 418  *  Get the event list from the kernel tracer and return that list in the CTF
 419  *  format.
 420  */
 421 ssize_t kernel_list_events(int tracer_fd, char **list)
 422 {
 423         int fd;
 424         char *buf, *line = NULL;
 425         size_t nb, nbmem, total = 0;
 426         ssize_t size;
 427         FILE *fp;
 428
 429         fd = kernctl_tracepoint_list(tracer_fd);
 430         if (fd < 0) {
 431                 perror("kernel tracepoint list");
 432                 goto error;
 433         }
 434
 435         fp = fdopen(fd, "r");
 436         if (fp == NULL) {
 437                 perror("kernel tracepoint list fdopen");
 438                 goto error;
 439         }
 440
 441         /*
 442          * Init memory size counter
 443          * See kernel-ctl.h for explanation of this value
 444          */
 445         nbmem = KERNEL_EVENT_LIST_SIZE;
 446         buf = malloc(nbmem);
 447
 448         while ((size = getline(&line, &nb, fp)) != -1) {
 449                 if (total + size > nbmem) {
 450                         DBG("Reallocating event list from %zd to %zd bytes", nbmem,
 451                                         total + size + KERNEL_EVENT_LIST_SIZE);
 452                         /* Adding the default size again */
 453                         nbmem = total + size + KERNEL_EVENT_LIST_SIZE;
 454                         buf = realloc(buf, nbmem);
 455                         if (buf == NULL) {
 456                                 perror("realloc list events");
 457                                 goto error;
 458                         }
 459                 }
 460                 memcpy(buf + total, line, size);
 461                 total += size;
 462         }
 463
 464         *list = buf;
 465
 466         DBG("Kernel list events done");
 467
 468         return total;
 469
 470 error:
 471         return -1;
 472 }