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                 ERR("Unable to enable event %s for channel %s", ev->name, channel->channel->name);
 140                 goto error;
 141         }
 142
 143         event->fd = ret;
 144         /* Prevent fd duplication after execlp() */
 145         ret = fcntl(event->fd, F_SETFD, FD_CLOEXEC);
 146         if (ret < 0) {
 147                 perror("fcntl session fd");
 148         }
 149
 150         /* Add event to event list */
 151         cds_list_add(&event->list, &channel->events_list.head);
 152         DBG("Event %s enabled (fd: %d)", ev->name, event->fd);
 153
 154         return 0;
 155
 156 error:
 157         return -1;
 158 }
 159
 160 /*
 161  *  kernel_open_metadata
 162  *
 163  *  Create kernel metadata, open from the kernel tracer and add it to the
 164  *  kernel session.
 165  */
 166 int kernel_open_metadata(struct ltt_kernel_session *session)
 167 {
 168         int ret;
 169         struct ltt_kernel_metadata *lkm;
 170
 171         /* Allocate kernel metadata */
 172         lkm = trace_create_kernel_metadata();
 173         if (lkm == NULL) {
 174                 goto error;
 175         }
 176
 177         /* Kernel tracer metadata creation */
 178         ret = kernctl_open_metadata(session->fd, &lkm->conf->attr);
 179         if (ret < 0) {
 180                 goto error;
 181         }
 182
 183         lkm->fd = ret;
 184         /* Prevent fd duplication after execlp() */
 185         ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC);
 186         if (ret < 0) {
 187                 perror("fcntl session fd");
 188         }
 189
 190         session->metadata = lkm;
 191
 192         DBG("Kernel metadata opened (fd: %d and path: %s)", lkm->fd, lkm->pathname);
 193
 194         return 0;
 195
 196 error:
 197         return -1;
 198 }
 199
 200 /*
 201  *  kernel_start_session
 202  *
 203  *  Start tracing session.
 204  */
 205 int kernel_start_session(struct ltt_kernel_session *session)
 206 {
 207         int ret;
 208
 209         ret = kernctl_start_session(session->fd);
 210         if (ret < 0) {
 211                 perror("ioctl start session");
 212                 goto error;
 213         }
 214
 215         DBG("Kernel session started");
 216
 217         return 0;
 218
 219 error:
 220         return ret;
 221 }
 222
 223 /*
 224  *  kernel_wait_quiescent
 225  *
 226  *  Make a kernel wait to make sure in-flight probe have completed.
 227  */
 228 void kernel_wait_quiescent(int fd)
 229 {
 230         int ret;
 231
 232         DBG("Kernel quiescent wait on %d", fd);
 233
 234         ret = kernctl_wait_quiescent(fd);
 235         if (ret < 0) {
 236                 perror("wait quiescent ioctl");
 237                 ERR("Kernel quiescent wait failed");
 238         }
 239 }
 240
 241 /*
 242  *  kernel_metadata_flush_buffer
 243  *
 244  *  Force flush buffer of metadata.
 245  */
 246 int kernel_metadata_flush_buffer(int fd)
 247 {
 248         int ret;
 249
 250         ret = kernctl_buffer_flush(fd);
 251         if (ret < 0) {
 252                 ERR("Fail to flush metadata buffers %d (ret: %d", fd, ret);
 253         }
 254
 255         return 0;
 256 }
 257
 258 /*
 259  *  kernel_flush_buffer
 260  *
 261  *  Force flush buffer for channel.
 262  */
 263 int kernel_flush_buffer(struct ltt_kernel_channel *channel)
 264 {
 265         int ret;
 266         struct ltt_kernel_stream *stream;
 267
 268         DBG("Flush buffer for channel %s", channel->channel->name);
 269
 270         cds_list_for_each_entry(stream, &channel->stream_list.head, list) {
 271                 DBG("Flushing channel stream %d", stream->fd);
 272                 ret = kernctl_buffer_flush(stream->fd);
 273                 if (ret < 0) {
 274                         perror("ioctl");
 275                         ERR("Fail to flush buffer for stream %d (ret: %d)",
 276                                         stream->fd, ret);
 277                 }
 278         }
 279
 280         return 0;
 281 }
 282
 283 /*
 284  *  kernel_stop_session
 285  *
 286  *  Stop tracing session.
 287  */
 288 int kernel_stop_session(struct ltt_kernel_session *session)
 289 {
 290         int ret;
 291
 292         ret = kernctl_stop_session(session->fd);
 293         if (ret < 0) {
 294                 goto error;
 295         }
 296
 297         DBG("Kernel session stopped");
 298
 299         return 0;
 300
 301 error:
 302         return ret;
 303 }
 304
 305 /*
 306  *  kernel_open_channel_stream
 307  *
 308  *  Open stream of channel, register it to the kernel tracer and add it
 309  *  to the stream list of the channel.
 310  *
 311  *  Return the number of created stream. Else, a negative value.
 312  */
 313 int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
 314 {
 315         int ret;
 316         struct ltt_kernel_stream *lks;
 317
 318         while ((ret = kernctl_create_stream(channel->fd)) > 0) {
 319                 lks = trace_create_kernel_stream();
 320                 if (lks == NULL) {
 321                         close(ret);
 322                         goto error;
 323                 }
 324
 325                 lks->fd = ret;
 326                 /* Prevent fd duplication after execlp() */
 327                 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
 328                 if (ret < 0) {
 329                         perror("fcntl session fd");
 330                 }
 331
 332                 ret = asprintf(&lks->pathname, "%s/trace_%d",
 333                                 channel->pathname, channel->stream_count);
 334                 if (ret < 0) {
 335                         perror("asprintf kernel create stream");
 336                         goto error;
 337                 }
 338
 339                 /* Add stream to channe stream list */
 340                 cds_list_add(&lks->list, &channel->stream_list.head);
 341                 channel->stream_count++;
 342
 343                 DBG("Kernel stream %d created (fd: %d, state: %d, path: %s)",
 344                                 channel->stream_count, lks->fd, lks->state, lks->pathname);
 345         }
 346
 347         return channel->stream_count;
 348
 349 error:
 350         return -1;
 351 }
 352
 353 /*
 354  *  kernel_open_metadata_stream
 355  *
 356  *  Open the metadata stream and set it to the kernel session.
 357  */
 358 int kernel_open_metadata_stream(struct ltt_kernel_session *session)
 359 {
 360         int ret;
 361
 362         ret = kernctl_create_stream(session->metadata->fd);
 363         if (ret < 0) {
 364                 perror("kernel create metadata stream");
 365                 goto error;
 366         }
 367
 368         DBG("Kernel metadata stream created (fd: %d)", ret);
 369         session->metadata_stream_fd = ret;
 370         /* Prevent fd duplication after execlp() */
 371         ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC);
 372         if (ret < 0) {
 373                 perror("fcntl session fd");
 374         }
 375
 376         return 0;
 377
 378 error:
 379         return -1;
 380 }
 381
 382 /*
 383  *  kernel_list_events
 384  *
 385  *  Get the event list from the kernel tracer and return that list in the CTF
 386  *  format.
 387  */
 388 ssize_t kernel_list_events(int tracer_fd, char **list)
 389 {
 390         int fd;
 391         char *buf, *line = NULL;
 392         size_t nb, nbmem, total = 0;
 393         ssize_t size;
 394         FILE *fp;
 395
 396         fd = kernctl_tracepoint_list(tracer_fd);
 397         if (fd < 0) {
 398                 perror("kernel tracepoint list");
 399                 goto error;
 400         }
 401
 402         fp = fdopen(fd, "r");
 403         if (fp == NULL) {
 404                 perror("kernel tracepoint list fdopen");
 405                 goto error;
 406         }
 407
 408         /*
 409          * Init memory size counter
 410          * See kernel-ctl.h for explanation of this value
 411          */
 412         nbmem = KERNEL_EVENT_LIST_SIZE;
 413         buf = malloc(nbmem);
 414
 415         while ((size = getline(&line, &nb, fp)) != -1) {
 416                 if (total + size > nbmem) {
 417                         DBG("Reallocating event list from %zd to %zd bytes", nbmem,
 418                                         total + size + KERNEL_EVENT_LIST_SIZE);
 419                         /* Adding the default size again */
 420                         nbmem = total + size + KERNEL_EVENT_LIST_SIZE;
 421                         buf = realloc(buf, nbmem);
 422                         if (buf == NULL) {
 423                                 perror("realloc list events");
 424                                 goto error;
 425                         }
 426                 }
 427                 memcpy(buf + total, line, size);
 428                 total += size;
 429         }
 430
 431         *list = buf;
 432
 433         DBG("Kernel list events done");
 434
 435         return total;
 436
 437 error:
 438         return -1;
 439 }