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 lttng_event *ev, struct ltt_kernel_channel *channel)
 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_enable_event
 165  *
 166  *  Enable a kernel event.
 167  */
 168 int kernel_enable_event(struct ltt_kernel_event *event)
 169 {
 170         int ret;
 171
 172         ret = kernctl_enable(event->fd);
 173         if (ret < 0) {
 174                 perror("enable event ioctl");
 175                 goto error;
 176         }
 177
 178         event->enabled = 1;
 179         DBG("Kernel event %s enabled (fd: %d)", event->event->name, event->fd);
 180
 181         return 0;
 182
 183 error:
 184         return -1;
 185 }
 186
 187 /*
 188  *  kernel_disable_event
 189  *
 190  *  Disable a kernel event.
 191  */
 192 int kernel_disable_event(struct ltt_kernel_event *event)
 193 {
 194         int ret;
 195
 196         ret = kernctl_disable(event->fd);
 197         if (ret < 0) {
 198                 perror("disable event ioctl");
 199                 goto error;
 200         }
 201
 202         event->enabled = 0;
 203         DBG("Kernel event %s disabled (fd: %d)", event->event->name, event->fd);
 204
 205         return 0;
 206
 207 error:
 208         return -1;
 209 }
 210
 211 /*
 212  *  kernel_open_metadata
 213  *
 214  *  Create kernel metadata, open from the kernel tracer and add it to the
 215  *  kernel session.
 216  */
 217 int kernel_open_metadata(struct ltt_kernel_session *session)
 218 {
 219         int ret;
 220         struct ltt_kernel_metadata *lkm;
 221
 222         /* Allocate kernel metadata */
 223         lkm = trace_create_kernel_metadata();
 224         if (lkm == NULL) {
 225                 goto error;
 226         }
 227
 228         /* Kernel tracer metadata creation */
 229         ret = kernctl_open_metadata(session->fd, &lkm->conf->attr);
 230         if (ret < 0) {
 231                 goto error;
 232         }
 233
 234         lkm->fd = ret;
 235         /* Prevent fd duplication after execlp() */
 236         ret = fcntl(lkm->fd, F_SETFD, FD_CLOEXEC);
 237         if (ret < 0) {
 238                 perror("fcntl session fd");
 239         }
 240
 241         session->metadata = lkm;
 242
 243         DBG("Kernel metadata opened (fd: %d and path: %s)", lkm->fd, lkm->pathname);
 244
 245         return 0;
 246
 247 error:
 248         return -1;
 249 }
 250
 251 /*
 252  *  kernel_start_session
 253  *
 254  *  Start tracing session.
 255  */
 256 int kernel_start_session(struct ltt_kernel_session *session)
 257 {
 258         int ret;
 259
 260         ret = kernctl_start_session(session->fd);
 261         if (ret < 0) {
 262                 perror("ioctl start session");
 263                 goto error;
 264         }
 265
 266         DBG("Kernel session started");
 267
 268         return 0;
 269
 270 error:
 271         return ret;
 272 }
 273
 274 /*
 275  *  kernel_wait_quiescent
 276  *
 277  *  Make a kernel wait to make sure in-flight probe have completed.
 278  */
 279 void kernel_wait_quiescent(int fd)
 280 {
 281         int ret;
 282
 283         DBG("Kernel quiescent wait on %d", fd);
 284
 285         ret = kernctl_wait_quiescent(fd);
 286         if (ret < 0) {
 287                 perror("wait quiescent ioctl");
 288                 ERR("Kernel quiescent wait failed");
 289         }
 290 }
 291
 292 /*
 293  *  kernel_metadata_flush_buffer
 294  *
 295  *  Force flush buffer of metadata.
 296  */
 297 int kernel_metadata_flush_buffer(int fd)
 298 {
 299         int ret;
 300
 301         ret = kernctl_buffer_flush(fd);
 302         if (ret < 0) {
 303                 ERR("Fail to flush metadata buffers %d (ret: %d", fd, ret);
 304         }
 305
 306         return 0;
 307 }
 308
 309 /*
 310  *  kernel_flush_buffer
 311  *
 312  *  Force flush buffer for channel.
 313  */
 314 int kernel_flush_buffer(struct ltt_kernel_channel *channel)
 315 {
 316         int ret;
 317         struct ltt_kernel_stream *stream;
 318
 319         DBG("Flush buffer for channel %s", channel->channel->name);
 320
 321         cds_list_for_each_entry(stream, &channel->stream_list.head, list) {
 322                 DBG("Flushing channel stream %d", stream->fd);
 323                 ret = kernctl_buffer_flush(stream->fd);
 324                 if (ret < 0) {
 325                         perror("ioctl");
 326                         ERR("Fail to flush buffer for stream %d (ret: %d)",
 327                                         stream->fd, ret);
 328                 }
 329         }
 330
 331         return 0;
 332 }
 333
 334 /*
 335  *  kernel_stop_session
 336  *
 337  *  Stop tracing session.
 338  */
 339 int kernel_stop_session(struct ltt_kernel_session *session)
 340 {
 341         int ret;
 342
 343         ret = kernctl_stop_session(session->fd);
 344         if (ret < 0) {
 345                 goto error;
 346         }
 347
 348         DBG("Kernel session stopped");
 349
 350         return 0;
 351
 352 error:
 353         return ret;
 354 }
 355
 356 /*
 357  *  kernel_open_channel_stream
 358  *
 359  *  Open stream of channel, register it to the kernel tracer and add it
 360  *  to the stream list of the channel.
 361  *
 362  *  Return the number of created stream. Else, a negative value.
 363  */
 364 int kernel_open_channel_stream(struct ltt_kernel_channel *channel)
 365 {
 366         int ret;
 367         struct ltt_kernel_stream *lks;
 368
 369         while ((ret = kernctl_create_stream(channel->fd)) > 0) {
 370                 lks = trace_create_kernel_stream();
 371                 if (lks == NULL) {
 372                         close(ret);
 373                         goto error;
 374                 }
 375
 376                 lks->fd = ret;
 377                 /* Prevent fd duplication after execlp() */
 378                 ret = fcntl(lks->fd, F_SETFD, FD_CLOEXEC);
 379                 if (ret < 0) {
 380                         perror("fcntl session fd");
 381                 }
 382
 383                 ret = asprintf(&lks->pathname, "%s/trace_%d",
 384                                 channel->pathname, channel->stream_count);
 385                 if (ret < 0) {
 386                         perror("asprintf kernel create stream");
 387                         goto error;
 388                 }
 389
 390                 /* Add stream to channe stream list */
 391                 cds_list_add(&lks->list, &channel->stream_list.head);
 392                 channel->stream_count++;
 393
 394                 DBG("Kernel stream %d created (fd: %d, state: %d, path: %s)",
 395                                 channel->stream_count, lks->fd, lks->state, lks->pathname);
 396         }
 397
 398         return channel->stream_count;
 399
 400 error:
 401         return -1;
 402 }
 403
 404 /*
 405  *  kernel_open_metadata_stream
 406  *
 407  *  Open the metadata stream and set it to the kernel session.
 408  */
 409 int kernel_open_metadata_stream(struct ltt_kernel_session *session)
 410 {
 411         int ret;
 412
 413         ret = kernctl_create_stream(session->metadata->fd);
 414         if (ret < 0) {
 415                 perror("kernel create metadata stream");
 416                 goto error;
 417         }
 418
 419         DBG("Kernel metadata stream created (fd: %d)", ret);
 420         session->metadata_stream_fd = ret;
 421         /* Prevent fd duplication after execlp() */
 422         ret = fcntl(session->metadata_stream_fd, F_SETFD, FD_CLOEXEC);
 423         if (ret < 0) {
 424                 perror("fcntl session fd");
 425         }
 426
 427         return 0;
 428
 429 error:
 430         return -1;
 431 }
 432
 433 /*
 434  *  kernel_list_events
 435  *
 436  *  Get the event list from the kernel tracer and return that list in the CTF
 437  *  format.
 438  */
 439 ssize_t kernel_list_events(int tracer_fd, char **list)
 440 {
 441         int fd;
 442         char *buf, *line = NULL;
 443         size_t nb, nbmem, total = 0;
 444         ssize_t size;
 445         FILE *fp;
 446
 447         fd = kernctl_tracepoint_list(tracer_fd);
 448         if (fd < 0) {
 449                 perror("kernel tracepoint list");
 450                 goto error;
 451         }
 452
 453         fp = fdopen(fd, "r");
 454         if (fp == NULL) {
 455                 perror("kernel tracepoint list fdopen");
 456                 goto error;
 457         }
 458
 459         /*
 460          * Init memory size counter
 461          * See kernel-ctl.h for explanation of this value
 462          */
 463         nbmem = KERNEL_EVENT_LIST_SIZE;
 464         buf = malloc(nbmem);
 465
 466         while ((size = getline(&line, &nb, fp)) != -1) {
 467                 if (total + size > nbmem) {
 468                         DBG("Reallocating event list from %zd to %zd bytes", nbmem,
 469                                         total + size + KERNEL_EVENT_LIST_SIZE);
 470                         /* Adding the default size again */
 471                         nbmem = total + size + KERNEL_EVENT_LIST_SIZE;
 472                         buf = realloc(buf, nbmem);
 473                         if (buf == NULL) {
 474                                 perror("realloc list events");
 475                                 goto error;
 476                         }
 477                 }
 478                 memcpy(buf + total, line, size);
 479                 total += size;
 480         }
 481
 482         *list = buf;
 483
 484         DBG("Kernel list events done");
 485
 486         return total;
 487
 488 error:
 489         return -1;
 490 }