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         struct lttcomm_consumer_msg msg;
 105
 106         ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 107         if (ret != sizeof(msg)) {
 108                 DBG("Consumer received unexpected message size %zd (expects %zu)",
 109                         ret, sizeof(msg));
 110                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 111                 return ret;
 112         }
 113         if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
 114                 return -ENOENT;
 115         }
 116
 117         /* relayd needs RCU read-side lock */
 118         rcu_read_lock();
 119
 120         switch (msg.cmd_type) {
 121         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 122         {
 123                 ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
 124                                 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
 125                                 &msg.u.relayd_sock.sock);
 126                 goto end_nosignal;
 127         }
 128         case LTTNG_CONSUMER_ADD_CHANNEL:
 129         {
 130                 struct lttng_consumer_channel *new_channel;
 131                 int fds[1];
 132                 size_t nb_fd = 1;
 133
 134                 DBG("UST Consumer adding channel");
 135
 136                 /* block */
 137                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 138                         rcu_read_unlock();
 139                         return -EINTR;
 140                 }
 141                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 142                 if (ret != sizeof(fds)) {
 143                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 144                         rcu_read_unlock();
 145                         return ret;
 146                 }
 147
 148                 DBG("consumer_add_channel %d", msg.u.channel.channel_key);
 149
 150                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 151                                 fds[0], -1,
 152                                 msg.u.channel.mmap_len,
 153                                 msg.u.channel.max_sb_size,
 154                                 msg.u.channel.nb_init_streams);
 155                 if (new_channel == NULL) {
 156                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 157                         goto end_nosignal;
 158                 }
 159                 if (ctx->on_recv_channel != NULL) {
 160                         ret = ctx->on_recv_channel(new_channel);
 161                         if (ret == 0) {
 162                                 consumer_add_channel(new_channel);
 163                         } else if (ret < 0) {
 164                                 goto end_nosignal;
 165                         }
 166                 } else {
 167                         consumer_add_channel(new_channel);
 168                 }
 169                 goto end_nosignal;
 170         }
 171         case LTTNG_CONSUMER_ADD_STREAM:
 172         {
 173                 struct lttng_consumer_stream *new_stream;
 174                 int fds[2], stream_pipe;
 175                 size_t nb_fd = 2;
 176                 struct consumer_relayd_sock_pair *relayd = NULL;
 177                 int alloc_ret = 0;
 178
 179                 DBG("UST Consumer adding stream");
 180
 181                 /* block */
 182                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 183                         rcu_read_unlock();
 184                         return -EINTR;
 185                 }
 186                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 187                 if (ret != sizeof(fds)) {
 188                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 189                         rcu_read_unlock();
 190                         return ret;
 191                 }
 192
 193                 DBG("Consumer command ADD_STREAM chan %d stream %d",
 194                                 msg.u.stream.channel_key, msg.u.stream.stream_key);
 195
 196                 assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
 197                 new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
 198                                 msg.u.stream.stream_key,
 199                                 fds[0], fds[1],
 200                                 msg.u.stream.state,
 201                                 msg.u.stream.mmap_len,
 202                                 msg.u.stream.output,
 203                                 msg.u.stream.path_name,
 204                                 msg.u.stream.uid,
 205                                 msg.u.stream.gid,
 206                                 msg.u.stream.net_index,
 207                                 msg.u.stream.metadata_flag,
 208                                 msg.u.stream.session_id,
 209                                 &alloc_ret);
 210                 if (new_stream == NULL) {
 211                         switch (alloc_ret) {
 212                         case -ENOMEM:
 213                         case -EINVAL:
 214                         default:
 215                                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 216                                 break;
 217                         case -ENOENT:
 218                                 /*
 219                                  * We could not find the channel. Can happen if cpu hotplug
 220                                  * happens while tearing down.
 221                                  */
 222                                 DBG3("Could not find channel");
 223                                 break;
 224                         }
 225                         goto end_nosignal;
 226                 }
 227
 228                 /* The stream is not metadata. Get relayd reference if exists. */
 229                 relayd = consumer_find_relayd(msg.u.stream.net_index);
 230                 if (relayd != NULL) {
 231                         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
 232                         /* Add stream on the relayd */
 233                         ret = relayd_add_stream(&relayd->control_sock,
 234                                         msg.u.stream.name, msg.u.stream.path_name,
 235                                         &new_stream->relayd_stream_id);
 236                         pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 237                         if (ret < 0) {
 238                                 consumer_del_stream(new_stream, NULL);
 239                                 goto end_nosignal;
 240                         }
 241                 } else if (msg.u.stream.net_index != -1) {
 242                         ERR("Network sequence index %d unknown. Not adding stream.",
 243                                         msg.u.stream.net_index);
 244                         consumer_del_stream(new_stream, NULL);
 245                         goto end_nosignal;
 246                 }
 247
 248                 /* Do actions once stream has been received. */
 249                 if (ctx->on_recv_stream) {
 250                         ret = ctx->on_recv_stream(new_stream);
 251                         if (ret < 0) {
 252                                 consumer_del_stream(new_stream, NULL);
 253                                 goto end_nosignal;
 254                         }
 255                 }
 256
 257                 /* Get the right pipe where the stream will be sent. */
 258                 if (new_stream->metadata_flag) {
 259                         stream_pipe = ctx->consumer_metadata_pipe[1];
 260                 } else {
 261                         stream_pipe = ctx->consumer_data_pipe[1];
 262                 }
 263
 264                 do {
 265                         ret = write(stream_pipe, &new_stream, sizeof(new_stream));
 266                 } while (ret < 0 && errno == EINTR);
 267                 if (ret < 0) {
 268                         PERROR("Consumer write %s stream to pipe %d",
 269                                         new_stream->metadata_flag ? "metadata" : "data",
 270                                         stream_pipe);
 271                         consumer_del_stream(new_stream, NULL);
 272                         goto end_nosignal;
 273                 }
 274
 275                 DBG("UST consumer ADD_STREAM %s (%d,%d) with relayd id %" PRIu64,
 276                                 msg.u.stream.path_name, fds[0], fds[1],
 277                                 new_stream->relayd_stream_id);
 278                 break;
 279         }
 280         case LTTNG_CONSUMER_DESTROY_RELAYD:
 281         {
 282                 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
 283                 struct consumer_relayd_sock_pair *relayd;
 284
 285                 DBG("UST consumer destroying relayd %" PRIu64, index);
 286
 287                 /* Get relayd reference if exists. */
 288                 relayd = consumer_find_relayd(index);
 289                 if (relayd == NULL) {
 290                         ERR("Unable to find relayd %" PRIu64, index);
 291                         goto end_nosignal;
 292                 }
 293
 294                 /*
 295                  * Each relayd socket pair has a refcount of stream attached to it
 296                  * which tells if the relayd is still active or not depending on the
 297                  * refcount value.
 298                  *
 299                  * This will set the destroy flag of the relayd object and destroy it
 300                  * if the refcount reaches zero when called.
 301                  *
 302                  * The destroy can happen either here or when a stream fd hangs up.
 303                  */
 304                 consumer_flag_relayd_for_destroy(relayd);
 305
 306                 goto end_nosignal;
 307         }
 308         case LTTNG_CONSUMER_UPDATE_STREAM:
 309         {
 310                 rcu_read_unlock();
 311                 return -ENOSYS;
 312         }
 313         case LTTNG_CONSUMER_DATA_AVAILABLE:
 314         {
 315                 int32_t ret;
 316                 uint64_t id = msg.u.data_available.session_id;
 317
 318                 DBG("UST consumer data available command for id %" PRIu64, id);
 319
 320                 ret = consumer_data_available(id);
 321
 322                 /* Send back returned value to session daemon */
 323                 ret = lttcomm_send_unix_sock(sock, &ret, sizeof(ret));
 324                 if (ret < 0) {
 325                         PERROR("send data available ret code");
 326                 }
 327                 break;
 328         }
 329         default:
 330                 break;
 331         }
 332
 333 end_nosignal:
 334         rcu_read_unlock();
 335
 336         /*
 337          * Return 1 to indicate success since the 0 value can be a socket
 338          * shutdown during the recv() or send() call.
 339          */
 340         return 1;
 341 }
 342
 343 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
 344 {
 345         struct lttng_ust_object_data obj;
 346
 347         obj.handle = -1;
 348         obj.shm_fd = chan->shm_fd;
 349         obj.wait_fd = chan->wait_fd;
 350         obj.memory_map_size = chan->mmap_len;
 351         chan->handle = ustctl_map_channel(&obj);
 352         if (!chan->handle) {
 353                 return -ENOMEM;
 354         }
 355         chan->wait_fd_is_copy = 1;
 356         chan->shm_fd = -1;
 357
 358         return 0;
 359 }
 360
 361 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
 362 {
 363         ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
 364         stream->hangup_flush_done = 1;
 365 }
 366
 367 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
 368 {
 369         ustctl_unmap_channel(chan->handle);
 370 }
 371
 372 int lttng_ustconsumer_add_stream(struct lttng_consumer_stream *stream)
 373 {
 374         struct lttng_ust_object_data obj;
 375         int ret;
 376
 377         obj.handle = -1;
 378         obj.shm_fd = stream->shm_fd;
 379         obj.wait_fd = stream->wait_fd;
 380         obj.memory_map_size = stream->mmap_len;
 381         ret = ustctl_add_stream(stream->chan->handle, &obj);
 382         if (ret) {
 383                 ERR("UST ctl add_stream failed with ret %d", ret);
 384                 goto error;
 385         }
 386
 387         stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
 388         if (!stream->buf) {
 389                 ERR("UST ctl open_stream_read failed");
 390                 ret = -EBUSY;
 391                 goto error;
 392         }
 393
 394         /* ustctl_open_stream_read has closed the shm fd. */
 395         stream->wait_fd_is_copy = 1;
 396         stream->shm_fd = -1;
 397
 398         stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
 399         if (!stream->mmap_base) {
 400                 ERR("UST ctl get_mmap_base failed");
 401                 ret = -EINVAL;
 402                 goto mmap_error;
 403         }
 404
 405         return 0;
 406
 407 mmap_error:
 408         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 409 error:
 410         return ret;
 411 }
 412
 413 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
 414 {
 415         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 416 }
 417
 418
 419 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 420                 struct lttng_consumer_local_data *ctx)
 421 {
 422         unsigned long len, subbuf_size, padding;
 423         int err;
 424         long ret = 0;
 425         struct lttng_ust_shm_handle *handle;
 426         struct lttng_ust_lib_ring_buffer *buf;
 427         char dummy;
 428         ssize_t readlen;
 429
 430         DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
 431                 stream->wait_fd, stream->key);
 432
 433         /* We can consume the 1 byte written into the wait_fd by UST */
 434         if (!stream->hangup_flush_done) {
 435                 do {
 436                         readlen = read(stream->wait_fd, &dummy, 1);
 437                 } while (readlen == -1 && errno == EINTR);
 438                 if (readlen == -1) {
 439                         ret = readlen;
 440                         goto end;
 441                 }
 442         }
 443
 444         buf = stream->buf;
 445         handle = stream->chan->handle;
 446         /* Get the next subbuffer */
 447         err = ustctl_get_next_subbuf(handle, buf);
 448         if (err != 0) {
 449                 ret = err;      /* ustctl_get_next_subbuf returns negative, caller expect positive. */
 450                 /*
 451                  * This is a debug message even for single-threaded consumer,
 452                  * because poll() have more relaxed criterions than get subbuf,
 453                  * so get_subbuf may fail for short race windows where poll()
 454                  * would issue wakeups.
 455                  */
 456                 DBG("Reserving sub buffer failed (everything is normal, "
 457                                 "it is due to concurrency)");
 458                 goto end;
 459         }
 460         assert(stream->output == LTTNG_EVENT_MMAP);
 461         /* Get the full padded subbuffer size */
 462         err = ustctl_get_padded_subbuf_size(handle, buf, &len);
 463         assert(err == 0);
 464
 465         /* Get subbuffer data size (without padding) */
 466         err = ustctl_get_subbuf_size(handle, buf, &subbuf_size);
 467         assert(err == 0);
 468
 469         /* Make sure we don't get a subbuffer size bigger than the padded */
 470         assert(len >= subbuf_size);
 471
 472         padding = len - subbuf_size;
 473         /* write the subbuffer to the tracefile */
 474         ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size, padding);
 475         /*
 476          * The mmap operation should write subbuf_size amount of data when network
 477          * streaming or the full padding (len) size when we are _not_ streaming.
 478          */
 479         if ((ret != subbuf_size && stream->net_seq_idx != -1) ||
 480                         (ret != len && stream->net_seq_idx == -1)) {
 481                 /*
 482                  * Display the error but continue processing to try to release the
 483                  * subbuffer
 484                  */
 485                 ERR("Error writing to tracefile "
 486                                 "(ret: %zd != len: %lu != subbuf_size: %lu)",
 487                                 ret, len, subbuf_size);
 488         }
 489         err = ustctl_put_next_subbuf(handle, buf);
 490         assert(err == 0);
 491 end:
 492         return ret;
 493 }
 494
 495 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
 496 {
 497         int ret;
 498
 499         /* Opening the tracefile in write mode */
 500         if (stream->path_name != NULL && stream->net_seq_idx == -1) {
 501                 ret = run_as_open(stream->path_name,
 502                                 O_WRONLY|O_CREAT|O_TRUNC,
 503                                 S_IRWXU|S_IRWXG|S_IRWXO,
 504                                 stream->uid, stream->gid);
 505                 if (ret < 0) {
 506                         ERR("Opening %s", stream->path_name);
 507                         PERROR("open");
 508                         goto error;
 509                 }
 510                 stream->out_fd = ret;
 511         }
 512
 513         ret = lttng_ustconsumer_add_stream(stream);
 514         if (ret) {
 515                 consumer_del_stream(stream, NULL);
 516                 ret = -1;
 517                 goto error;
 518         }
 519
 520         /* we return 0 to let the library handle the FD internally */
 521         return 0;
 522
 523 error:
 524         return ret;
 525 }
 526
 527 /*
 528  * Check if data is still being extracted from the buffers for a specific
 529  * stream. Consumer data lock MUST be acquired before calling this function.
 530  *
 531  * Return 0 if the traced data are still getting read else 1 meaning that the
 532  * data is available for trace viewer reading.
 533  */
 534 int lttng_ustconsumer_data_available(struct lttng_consumer_stream *stream)
 535 {
 536         int ret;
 537
 538         assert(stream);
 539
 540         DBG("UST consumer checking data availability");
 541
 542         /*
 543          * Try to lock the stream mutex. On failure, we know that the stream is
 544          * being used else where hence there is data still being extracted.
 545          */
 546         ret = pthread_mutex_trylock(&stream->lock);
 547         if (ret == EBUSY) {
 548                 /* Data not available */
 549                 ret = 0;
 550                 goto end;
 551         }
 552         /* The stream is now locked so we can do our ustctl calls */
 553
 554         ret = ustctl_get_next_subbuf(stream->chan->handle, stream->buf);
 555         if (ret == 0) {
 556                 /* There is still data so let's put back this subbuffer. */
 557                 ret = ustctl_put_subbuf(stream->chan->handle, stream->buf);
 558                 assert(ret == 0);
 559                 goto end_unlock;
 560         }
 561
 562         /* Data is available to be read for this stream. */
 563         ret = 1;
 564
 565 end_unlock:
 566         pthread_mutex_unlock(&stream->lock);
 567 end:
 568         return ret;
 569 }