src/common/ust-consumer/ust-consumer.c

   1 /*
   2  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   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 along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <assert.h>
  21 #include <lttng/ust-ctl.h>
  22 #include <poll.h>
  23 #include <pthread.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <sys/mman.h>
  27 #include <sys/socket.h>
  28 #include <sys/stat.h>
  29 #include <sys/types.h>
  30 #include <inttypes.h>
  31 #include <unistd.h>
  32
  33 #include <common/common.h>
  34 #include <common/sessiond-comm/sessiond-comm.h>
  35 #include <common/relayd/relayd.h>
  36 #include <common/compat/fcntl.h>
  37
  38 #include "ust-consumer.h"
  39
  40 extern struct lttng_consumer_global_data consumer_data;
  41 extern int consumer_poll_timeout;
  42 extern volatile int consumer_quit;
  43
  44 /*
  45  * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
  46  * compiled out, we isolate it in this library.
  47  */
  48 int lttng_ustctl_get_mmap_read_offset(struct lttng_ust_shm_handle *handle,
  49                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *off)
  50 {
  51         return ustctl_get_mmap_read_offset(handle, buf, off);
  52 };
  53
  54 /*
  55  * Take a snapshot for a specific fd
  56  *
  57  * Returns 0 on success, < 0 on error
  58  */
  59 int lttng_ustconsumer_take_snapshot(struct lttng_consumer_local_data *ctx,
  60                 struct lttng_consumer_stream *stream)
  61 {
  62         int ret = 0;
  63
  64         ret = ustctl_snapshot(stream->chan->handle, stream->buf);
  65         if (ret != 0) {
  66                 errno = -ret;
  67                 PERROR("Getting sub-buffer snapshot.");
  68         }
  69
  70         return ret;
  71 }
  72
  73 /*
  74  * Get the produced position
  75  *
  76  * Returns 0 on success, < 0 on error
  77  */
  78 int lttng_ustconsumer_get_produced_snapshot(
  79                 struct lttng_consumer_local_data *ctx,
  80                 struct lttng_consumer_stream *stream,
  81                 unsigned long *pos)
  82 {
  83         int ret;
  84
  85         ret = ustctl_snapshot_get_produced(stream->chan->handle,
  86                         stream->buf, pos);
  87         if (ret != 0) {
  88                 errno = -ret;
  89                 PERROR("kernctl_snapshot_get_produced");
  90         }
  91
  92         return ret;
  93 }
  94
  95 /*
  96  * Receive command from session daemon and process it.
  97  *
  98  * Return 1 on success else a negative value or 0.
  99  */
 100 int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 101                 int sock, struct pollfd *consumer_sockpoll)
 102 {
 103         ssize_t ret;
 104         enum lttng_error_code ret_code = LTTNG_OK;
 105         struct lttcomm_consumer_msg msg;
 106
 107         ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 108         if (ret != sizeof(msg)) {
 109                 DBG("Consumer received unexpected message size %zd (expects %zu)",
 110                         ret, sizeof(msg));
 111                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 112                 return ret;
 113         }
 114         if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
 115                 /*
 116                  * Notify the session daemon that the command is completed.
 117                  *
 118                  * On transport layer error, the function call will print an error
 119                  * message so handling the returned code is a bit useless since we
 120                  * return an error code anyway.
 121                  */
 122                 (void) consumer_send_status_msg(sock, ret_code);
 123                 return -ENOENT;
 124         }
 125
 126         /* relayd needs RCU read-side lock */
 127         rcu_read_lock();
 128
 129         switch (msg.cmd_type) {
 130         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 131         {
 132                 /* Session daemon status message are handled in the following call. */
 133                 ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
 134                                 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
 135                                 &msg.u.relayd_sock.sock);
 136                 goto end_nosignal;
 137         }
 138         case LTTNG_CONSUMER_ADD_CHANNEL:
 139         {
 140                 struct lttng_consumer_channel *new_channel;
 141                 int fds[1];
 142                 size_t nb_fd = 1;
 143
 144                 DBG("UST Consumer adding channel");
 145
 146                 /* First send a status message before receiving the fds. */
 147                 ret = consumer_send_status_msg(sock, ret_code);
 148                 if (ret < 0) {
 149                         /* Somehow, the session daemon is not responding anymore. */
 150                         goto end_nosignal;
 151                 }
 152
 153                 /* block */
 154                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 155                         rcu_read_unlock();
 156                         return -EINTR;
 157                 }
 158                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 159                 if (ret != sizeof(fds)) {
 160                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 161                         rcu_read_unlock();
 162                         return ret;
 163                 }
 164
 165                 /*
 166                  * Send status code to session daemon only if the recv works. If the
 167                  * above recv() failed, the session daemon is notified through the
 168                  * error socket and the teardown is eventually done.
 169                  */
 170                 ret = consumer_send_status_msg(sock, ret_code);
 171                 if (ret < 0) {
 172                         /* Somehow, the session daemon is not responding anymore. */
 173                         goto end_nosignal;
 174                 }
 175
 176                 DBG("consumer_add_channel %d", msg.u.channel.channel_key);
 177
 178                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 179                                 fds[0], -1,
 180                                 msg.u.channel.mmap_len,
 181                                 msg.u.channel.max_sb_size,
 182                                 msg.u.channel.nb_init_streams);
 183                 if (new_channel == NULL) {
 184                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 185                         goto end_nosignal;
 186                 }
 187                 if (ctx->on_recv_channel != NULL) {
 188                         ret = ctx->on_recv_channel(new_channel);
 189                         if (ret == 0) {
 190                                 consumer_add_channel(new_channel);
 191                         } else if (ret < 0) {
 192                                 goto end_nosignal;
 193                         }
 194                 } else {
 195                         consumer_add_channel(new_channel);
 196                 }
 197                 goto end_nosignal;
 198         }
 199         case LTTNG_CONSUMER_ADD_STREAM:
 200         {
 201                 struct lttng_consumer_stream *new_stream;
 202                 int fds[2], stream_pipe;
 203                 size_t nb_fd = 2;
 204                 struct consumer_relayd_sock_pair *relayd = NULL;
 205                 int alloc_ret = 0;
 206
 207                 DBG("UST Consumer adding stream");
 208
 209                 /* First send a status message before receiving the fds. */
 210                 ret = consumer_send_status_msg(sock, ret_code);
 211                 if (ret < 0) {
 212                         /* Somehow, the session daemon is not responding anymore. */
 213                         goto end_nosignal;
 214                 }
 215
 216                 /* block */
 217                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 218                         rcu_read_unlock();
 219                         return -EINTR;
 220                 }
 221                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 222                 if (ret != sizeof(fds)) {
 223                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 224                         rcu_read_unlock();
 225                         return ret;
 226                 }
 227
 228                 /*
 229                  * Send status code to session daemon only if the recv works. If the
 230                  * above recv() failed, the session daemon is notified through the
 231                  * error socket and the teardown is eventually done.
 232                  */
 233                 ret = consumer_send_status_msg(sock, ret_code);
 234                 if (ret < 0) {
 235                         /* Somehow, the session daemon is not responding anymore. */
 236                         goto end_nosignal;
 237                 }
 238
 239                 DBG("Consumer command ADD_STREAM chan %d stream %d",
 240                                 msg.u.stream.channel_key, msg.u.stream.stream_key);
 241
 242                 assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
 243                 new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
 244                                 msg.u.stream.stream_key,
 245                                 fds[0], fds[1],
 246                                 msg.u.stream.state,
 247                                 msg.u.stream.mmap_len,
 248                                 msg.u.stream.output,
 249                                 msg.u.stream.path_name,
 250                                 msg.u.stream.uid,
 251                                 msg.u.stream.gid,
 252                                 msg.u.stream.net_index,
 253                                 msg.u.stream.metadata_flag,
 254                                 msg.u.stream.session_id,
 255                                 &alloc_ret);
 256                 if (new_stream == NULL) {
 257                         switch (alloc_ret) {
 258                         case -ENOMEM:
 259                         case -EINVAL:
 260                         default:
 261                                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 262                                 break;
 263                         case -ENOENT:
 264                                 /*
 265                                  * We could not find the channel. Can happen if cpu hotplug
 266                                  * happens while tearing down.
 267                                  */
 268                                 DBG3("Could not find channel");
 269                                 break;
 270                         }
 271                         goto end_nosignal;
 272                 }
 273
 274                 /* The stream is not metadata. Get relayd reference if exists. */
 275                 relayd = consumer_find_relayd(msg.u.stream.net_index);
 276                 if (relayd != NULL) {
 277                         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
 278                         /* Add stream on the relayd */
 279                         ret = relayd_add_stream(&relayd->control_sock,
 280                                         msg.u.stream.name, msg.u.stream.path_name,
 281                                         &new_stream->relayd_stream_id);
 282                         pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 283                         if (ret < 0) {
 284                                 consumer_del_stream(new_stream, NULL);
 285                                 goto end_nosignal;
 286                         }
 287                 } else if (msg.u.stream.net_index != -1) {
 288                         ERR("Network sequence index %d unknown. Not adding stream.",
 289                                         msg.u.stream.net_index);
 290                         consumer_del_stream(new_stream, NULL);
 291                         goto end_nosignal;
 292                 }
 293
 294                 /* Do actions once stream has been received. */
 295                 if (ctx->on_recv_stream) {
 296                         ret = ctx->on_recv_stream(new_stream);
 297                         if (ret < 0) {
 298                                 consumer_del_stream(new_stream, NULL);
 299                                 goto end_nosignal;
 300                         }
 301                 }
 302
 303                 /* Get the right pipe where the stream will be sent. */
 304                 if (new_stream->metadata_flag) {
 305                         stream_pipe = ctx->consumer_metadata_pipe[1];
 306                 } else {
 307                         stream_pipe = ctx->consumer_data_pipe[1];
 308                 }
 309
 310                 do {
 311                         ret = write(stream_pipe, &new_stream, sizeof(new_stream));
 312                 } while (ret < 0 && errno == EINTR);
 313                 if (ret < 0) {
 314                         PERROR("Consumer write %s stream to pipe %d",
 315                                         new_stream->metadata_flag ? "metadata" : "data",
 316                                         stream_pipe);
 317                         consumer_del_stream(new_stream, NULL);
 318                         goto end_nosignal;
 319                 }
 320
 321                 DBG("UST consumer ADD_STREAM %s (%d,%d) with relayd id %" PRIu64,
 322                                 msg.u.stream.path_name, fds[0], fds[1],
 323                                 new_stream->relayd_stream_id);
 324                 break;
 325         }
 326         case LTTNG_CONSUMER_DESTROY_RELAYD:
 327         {
 328                 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
 329                 struct consumer_relayd_sock_pair *relayd;
 330
 331                 DBG("UST consumer destroying relayd %" PRIu64, index);
 332
 333                 /* Get relayd reference if exists. */
 334                 relayd = consumer_find_relayd(index);
 335                 if (relayd == NULL) {
 336                         ERR("Unable to find relayd %" PRIu64, index);
 337                         ret_code = LTTNG_ERR_NO_CONSUMER;
 338                 }
 339
 340                 /*
 341                  * Each relayd socket pair has a refcount of stream attached to it
 342                  * which tells if the relayd is still active or not depending on the
 343                  * refcount value.
 344                  *
 345                  * This will set the destroy flag of the relayd object and destroy it
 346                  * if the refcount reaches zero when called.
 347                  *
 348                  * The destroy can happen either here or when a stream fd hangs up.
 349                  */
 350                 if (relayd) {
 351                         consumer_flag_relayd_for_destroy(relayd);
 352                 }
 353
 354                 ret = consumer_send_status_msg(sock, ret_code);
 355                 if (ret < 0) {
 356                         /* Somehow, the session daemon is not responding anymore. */
 357                         goto end_nosignal;
 358                 }
 359
 360                 goto end_nosignal;
 361         }
 362         case LTTNG_CONSUMER_UPDATE_STREAM:
 363         {
 364                 rcu_read_unlock();
 365                 return -ENOSYS;
 366         }
 367         case LTTNG_CONSUMER_DATA_PENDING:
 368         {
 369                 int32_t ret;
 370                 uint64_t id = msg.u.data_pending.session_id;
 371
 372                 DBG("UST consumer data pending command for id %" PRIu64, id);
 373
 374                 ret = consumer_data_pending(id);
 375
 376                 /* Send back returned value to session daemon */
 377                 ret = lttcomm_send_unix_sock(sock, &ret, sizeof(ret));
 378                 if (ret < 0) {
 379                         PERROR("send data pending ret code");
 380                 }
 381
 382                 /*
 383                  * No need to send back a status message since the data pending
 384                  * returned value is the response.
 385                  */
 386                 break;
 387         }
 388         default:
 389                 break;
 390         }
 391
 392 end_nosignal:
 393         rcu_read_unlock();
 394
 395         /*
 396          * Return 1 to indicate success since the 0 value can be a socket
 397          * shutdown during the recv() or send() call.
 398          */
 399         return 1;
 400 }
 401
 402 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
 403 {
 404         struct lttng_ust_object_data obj;
 405
 406         obj.handle = -1;
 407         obj.shm_fd = chan->shm_fd;
 408         obj.wait_fd = chan->wait_fd;
 409         obj.memory_map_size = chan->mmap_len;
 410         chan->handle = ustctl_map_channel(&obj);
 411         if (!chan->handle) {
 412                 return -ENOMEM;
 413         }
 414         chan->wait_fd_is_copy = 1;
 415         chan->shm_fd = -1;
 416
 417         return 0;
 418 }
 419
 420 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
 421 {
 422         ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
 423         stream->hangup_flush_done = 1;
 424 }
 425
 426 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
 427 {
 428         ustctl_unmap_channel(chan->handle);
 429 }
 430
 431 int lttng_ustconsumer_add_stream(struct lttng_consumer_stream *stream)
 432 {
 433         struct lttng_ust_object_data obj;
 434         int ret;
 435
 436         obj.handle = -1;
 437         obj.shm_fd = stream->shm_fd;
 438         obj.wait_fd = stream->wait_fd;
 439         obj.memory_map_size = stream->mmap_len;
 440         ret = ustctl_add_stream(stream->chan->handle, &obj);
 441         if (ret) {
 442                 ERR("UST ctl add_stream failed with ret %d", ret);
 443                 goto error;
 444         }
 445
 446         stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
 447         if (!stream->buf) {
 448                 ERR("UST ctl open_stream_read failed");
 449                 ret = -EBUSY;
 450                 goto error;
 451         }
 452
 453         /* ustctl_open_stream_read has closed the shm fd. */
 454         stream->wait_fd_is_copy = 1;
 455         stream->shm_fd = -1;
 456
 457         stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
 458         if (!stream->mmap_base) {
 459                 ERR("UST ctl get_mmap_base failed");
 460                 ret = -EINVAL;
 461                 goto mmap_error;
 462         }
 463
 464         return 0;
 465
 466 mmap_error:
 467         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 468 error:
 469         return ret;
 470 }
 471
 472 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
 473 {
 474         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 475 }
 476
 477
 478 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 479                 struct lttng_consumer_local_data *ctx)
 480 {
 481         unsigned long len, subbuf_size, padding;
 482         int err;
 483         long ret = 0;
 484         struct lttng_ust_shm_handle *handle;
 485         struct lttng_ust_lib_ring_buffer *buf;
 486         char dummy;
 487         ssize_t readlen;
 488
 489         DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
 490                 stream->wait_fd, stream->key);
 491
 492         /* We can consume the 1 byte written into the wait_fd by UST */
 493         if (!stream->hangup_flush_done) {
 494                 do {
 495                         readlen = read(stream->wait_fd, &dummy, 1);
 496                 } while (readlen == -1 && errno == EINTR);
 497                 if (readlen == -1) {
 498                         ret = readlen;
 499                         goto end;
 500                 }
 501         }
 502
 503         buf = stream->buf;
 504         handle = stream->chan->handle;
 505         /* Get the next subbuffer */
 506         err = ustctl_get_next_subbuf(handle, buf);
 507         if (err != 0) {
 508                 ret = err;      /* ustctl_get_next_subbuf returns negative, caller expect positive. */
 509                 /*
 510                  * This is a debug message even for single-threaded consumer,
 511                  * because poll() have more relaxed criterions than get subbuf,
 512                  * so get_subbuf may fail for short race windows where poll()
 513                  * would issue wakeups.
 514                  */
 515                 DBG("Reserving sub buffer failed (everything is normal, "
 516                                 "it is due to concurrency)");
 517                 goto end;
 518         }
 519         assert(stream->output == LTTNG_EVENT_MMAP);
 520         /* Get the full padded subbuffer size */
 521         err = ustctl_get_padded_subbuf_size(handle, buf, &len);
 522         assert(err == 0);
 523
 524         /* Get subbuffer data size (without padding) */
 525         err = ustctl_get_subbuf_size(handle, buf, &subbuf_size);
 526         assert(err == 0);
 527
 528         /* Make sure we don't get a subbuffer size bigger than the padded */
 529         assert(len >= subbuf_size);
 530
 531         padding = len - subbuf_size;
 532         /* write the subbuffer to the tracefile */
 533         ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size, padding);
 534         /*
 535          * The mmap operation should write subbuf_size amount of data when network
 536          * streaming or the full padding (len) size when we are _not_ streaming.
 537          */
 538         if ((ret != subbuf_size && stream->net_seq_idx != -1) ||
 539                         (ret != len && stream->net_seq_idx == -1)) {
 540                 /*
 541                  * Display the error but continue processing to try to release the
 542                  * subbuffer
 543                  */
 544                 ERR("Error writing to tracefile "
 545                                 "(ret: %zd != len: %lu != subbuf_size: %lu)",
 546                                 ret, len, subbuf_size);
 547         }
 548         err = ustctl_put_next_subbuf(handle, buf);
 549         assert(err == 0);
 550 end:
 551         return ret;
 552 }
 553
 554 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
 555 {
 556         int ret;
 557
 558         /* Opening the tracefile in write mode */
 559         if (stream->path_name != NULL && stream->net_seq_idx == -1) {
 560                 ret = run_as_open(stream->path_name,
 561                                 O_WRONLY|O_CREAT|O_TRUNC,
 562                                 S_IRWXU|S_IRWXG|S_IRWXO,
 563                                 stream->uid, stream->gid);
 564                 if (ret < 0) {
 565                         ERR("Opening %s", stream->path_name);
 566                         PERROR("open");
 567                         goto error;
 568                 }
 569                 stream->out_fd = ret;
 570         }
 571
 572         ret = lttng_ustconsumer_add_stream(stream);
 573         if (ret) {
 574                 consumer_del_stream(stream, NULL);
 575                 ret = -1;
 576                 goto error;
 577         }
 578
 579         /* we return 0 to let the library handle the FD internally */
 580         return 0;
 581
 582 error:
 583         return ret;
 584 }
 585
 586 /*
 587  * Check if data is still being extracted from the buffers for a specific
 588  * stream. Consumer data lock MUST be acquired before calling this function
 589  * and the stream lock.
 590  *
 591  * Return 1 if the traced data are still getting read else 0 meaning that the
 592  * data is available for trace viewer reading.
 593  */
 594 int lttng_ustconsumer_data_pending(struct lttng_consumer_stream *stream)
 595 {
 596         int ret;
 597
 598         assert(stream);
 599
 600         DBG("UST consumer checking data pending");
 601
 602         ret = ustctl_get_next_subbuf(stream->chan->handle, stream->buf);
 603         if (ret == 0) {
 604                 /* There is still data so let's put back this subbuffer. */
 605                 ret = ustctl_put_subbuf(stream->chan->handle, stream->buf);
 606                 assert(ret == 0);
 607                 ret = 1;  /* Data is pending */
 608                 goto end;
 609         }
 610
 611         /* Data is NOT pending so ready to be read. */
 612         ret = 0;
 613
 614 end:
 615         return ret;
 616 }