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 <poll.h>
  22 #include <pthread.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sys/mman.h>
  26 #include <sys/socket.h>
  27 #include <sys/stat.h>
  28 #include <sys/types.h>
  29 #include <unistd.h>
  30 #include <lttng/ust-ctl.h>
  31
  32 #include <common/common.h>
  33 #include <common/sessiond-comm/sessiond-comm.h>
  34 #include <common/relayd/relayd.h>
  35 #include <common/compat/fcntl.h>
  36
  37 #include "ust-consumer.h"
  38
  39 extern struct lttng_consumer_global_data consumer_data;
  40 extern int consumer_poll_timeout;
  41 extern volatile int consumer_quit;
  42
  43 /*
  44  * Mmap the ring buffer, read it and write the data to the tracefile.
  45  *
  46  * Returns the number of bytes written, else negative value on error.
  47  */
  48 ssize_t lttng_ustconsumer_on_read_subbuffer_mmap(
  49                 struct lttng_consumer_local_data *ctx,
  50                 struct lttng_consumer_stream *stream, unsigned long len)
  51 {
  52         unsigned long mmap_offset;
  53         long ret = 0, written = 0;
  54         off_t orig_offset = stream->out_fd_offset;
  55         int outfd = stream->out_fd;
  56         uint64_t metadata_id;
  57         struct consumer_relayd_sock_pair *relayd = NULL;
  58
  59         /* RCU lock for the relayd pointer */
  60         rcu_read_lock();
  61
  62         /* Flag that the current stream if set for network streaming. */
  63         if (stream->net_seq_idx != -1) {
  64                 relayd = consumer_find_relayd(stream->net_seq_idx);
  65                 if (relayd == NULL) {
  66                         ERR("UST consumer mmap(), unable to find relay for index %d",
  67                                         stream->net_seq_idx);
  68                         goto end;
  69                 }
  70         }
  71
  72         /* get the offset inside the fd to mmap */
  73         ret = ustctl_get_mmap_read_offset(stream->chan->handle,
  74                 stream->buf, &mmap_offset);
  75         if (ret != 0) {
  76                 errno = -ret;
  77                 PERROR("ustctl_get_mmap_read_offset");
  78                 written = ret;
  79                 goto end;
  80         }
  81
  82         /* Handle stream on the relayd if the output is on the network */
  83         if (relayd) {
  84                 unsigned long netlen = len;
  85
  86                 if (stream->metadata_flag) {
  87                         /* Only lock if metadata since we use the control socket. */
  88                         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
  89                         netlen += sizeof(stream->relayd_stream_id);
  90                 }
  91
  92                 ret = consumer_handle_stream_before_relayd(stream, netlen);
  93                 if (ret >= 0) {
  94                         outfd = ret;
  95
  96                         /* Write metadata stream id before payload */
  97                         if (stream->metadata_flag) {
  98                                 metadata_id = htobe64(stream->relayd_stream_id);
  99                                 do {
 100                                         ret = write(outfd, (void *) &metadata_id,
 101                                                         sizeof(stream->relayd_stream_id));
 102                                 } while (ret < 0 && errno == EINTR);
 103                                 if (ret < 0) {
 104                                         PERROR("write metadata stream id");
 105                                         written = ret;
 106                                         goto end;
 107                                 }
 108                                 DBG("Metadata stream id %zu written before data",
 109                                                 stream->relayd_stream_id);
 110                         }
 111                 }
 112                 /* Else, use the default set before which is the filesystem. */
 113         }
 114
 115         while (len > 0) {
 116                 do {
 117                         ret = write(outfd, stream->mmap_base + mmap_offset, len);
 118                 } while (ret < 0 && errno == EINTR);
 119                 if (ret < 0) {
 120                         PERROR("Error in file write");
 121                         if (written == 0) {
 122                                 written = ret;
 123                         }
 124                         goto end;
 125                 } else if (ret > len) {
 126                         PERROR("ret %ld > len %lu", ret, len);
 127                         written += ret;
 128                         goto end;
 129                 } else {
 130                         len -= ret;
 131                         mmap_offset += ret;
 132                 }
 133                 DBG("UST mmap write() ret %ld (len %lu)", ret, len);
 134
 135                 /* This call is useless on a socket so better save a syscall. */
 136                 if (!relayd) {
 137                         /* This won't block, but will start writeout asynchronously */
 138                         lttng_sync_file_range(outfd, stream->out_fd_offset, ret,
 139                                         SYNC_FILE_RANGE_WRITE);
 140                         stream->out_fd_offset += ret;
 141                 }
 142                 written += ret;
 143         }
 144         lttng_consumer_sync_trace_file(stream, orig_offset);
 145
 146 end:
 147         if (relayd && stream->metadata_flag) {
 148                 pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 149         }
 150         rcu_read_unlock();
 151         return written;
 152 }
 153
 154 /*
 155  * Splice the data from the ring buffer to the tracefile.
 156  *
 157  * Returns the number of bytes spliced.
 158  */
 159 ssize_t lttng_ustconsumer_on_read_subbuffer_splice(
 160                 struct lttng_consumer_local_data *ctx,
 161                 struct lttng_consumer_stream *stream, unsigned long len)
 162 {
 163         return -ENOSYS;
 164 }
 165
 166 /*
 167  * Take a snapshot for a specific fd
 168  *
 169  * Returns 0 on success, < 0 on error
 170  */
 171 int lttng_ustconsumer_take_snapshot(struct lttng_consumer_local_data *ctx,
 172                 struct lttng_consumer_stream *stream)
 173 {
 174         int ret = 0;
 175
 176         ret = ustctl_snapshot(stream->chan->handle, stream->buf);
 177         if (ret != 0) {
 178                 errno = -ret;
 179                 PERROR("Getting sub-buffer snapshot.");
 180         }
 181
 182         return ret;
 183 }
 184
 185 /*
 186  * Get the produced position
 187  *
 188  * Returns 0 on success, < 0 on error
 189  */
 190 int lttng_ustconsumer_get_produced_snapshot(
 191                 struct lttng_consumer_local_data *ctx,
 192                 struct lttng_consumer_stream *stream,
 193                 unsigned long *pos)
 194 {
 195         int ret;
 196
 197         ret = ustctl_snapshot_get_produced(stream->chan->handle,
 198                         stream->buf, pos);
 199         if (ret != 0) {
 200                 errno = -ret;
 201                 PERROR("kernctl_snapshot_get_produced");
 202         }
 203
 204         return ret;
 205 }
 206
 207 int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 208                 int sock, struct pollfd *consumer_sockpoll)
 209 {
 210         ssize_t ret;
 211         struct lttcomm_consumer_msg msg;
 212
 213         ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 214         if (ret != sizeof(msg)) {
 215                 DBG("Consumer received unexpected message size %zd (expects %zu)",
 216                         ret, sizeof(msg));
 217                 lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 218                 return ret;
 219         }
 220         if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
 221                 return -ENOENT;
 222         }
 223
 224         /* relayd need RCU read-side lock */
 225         rcu_read_lock();
 226
 227         switch (msg.cmd_type) {
 228         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 229         {
 230                 int fd;
 231                 struct consumer_relayd_sock_pair *relayd;
 232
 233                 DBG("UST Consumer adding relayd socket");
 234
 235                 /* Get relayd reference if exists. */
 236                 relayd = consumer_find_relayd(msg.u.relayd_sock.net_index);
 237                 if (relayd == NULL) {
 238                         /* Not found. Allocate one. */
 239                         relayd = consumer_allocate_relayd_sock_pair(
 240                                         msg.u.relayd_sock.net_index);
 241                         if (relayd == NULL) {
 242                                 lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 243                                 goto end_nosignal;
 244                         }
 245                 }
 246
 247                 /* Poll on consumer socket. */
 248                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 249                         return -EINTR;
 250                 }
 251
 252                 /* Get relayd socket from session daemon */
 253                 ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
 254                 if (ret != sizeof(fd)) {
 255                         lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 256                         goto end_nosignal;
 257                 }
 258
 259                 /* Copy socket information and received FD */
 260                 switch (msg.u.relayd_sock.type) {
 261                 case LTTNG_STREAM_CONTROL:
 262                         /* Copy received lttcomm socket */
 263                         lttcomm_copy_sock(&relayd->control_sock, &msg.u.relayd_sock.sock);
 264                         ret = lttcomm_create_sock(&relayd->control_sock);
 265                         if (ret < 0) {
 266                                 goto end_nosignal;
 267                         }
 268
 269                         /* Close the created socket fd which is useless */
 270                         close(relayd->control_sock.fd);
 271
 272                         /* Assign new file descriptor */
 273                         relayd->control_sock.fd = fd;
 274                         break;
 275                 case LTTNG_STREAM_DATA:
 276                         /* Copy received lttcomm socket */
 277                         lttcomm_copy_sock(&relayd->data_sock, &msg.u.relayd_sock.sock);
 278                         ret = lttcomm_create_sock(&relayd->data_sock);
 279                         if (ret < 0) {
 280                                 goto end_nosignal;
 281                         }
 282
 283                         /* Close the created socket fd which is useless */
 284                         close(relayd->data_sock.fd);
 285
 286                         /* Assign new file descriptor */
 287                         relayd->data_sock.fd = fd;
 288                         break;
 289                 default:
 290                         ERR("Unknown relayd socket type");
 291                         goto end_nosignal;
 292                 }
 293
 294                 DBG("Consumer %s socket created successfully with net idx %d (fd: %d)",
 295                                 msg.u.relayd_sock.type == LTTNG_STREAM_CONTROL ? "control" : "data",
 296                                 relayd->net_seq_idx, fd);
 297
 298                 /*
 299                  * Add relayd socket pair to consumer data hashtable. If object already
 300                  * exists or on error, the function gracefully returns.
 301                  */
 302                 consumer_add_relayd(relayd);
 303
 304                 goto end_nosignal;
 305         }
 306         case LTTNG_CONSUMER_ADD_CHANNEL:
 307         {
 308                 struct lttng_consumer_channel *new_channel;
 309                 int fds[1];
 310                 size_t nb_fd = 1;
 311
 312                 DBG("UST Consumer adding channel");
 313
 314                 /* block */
 315                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 316                         return -EINTR;
 317                 }
 318                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 319                 if (ret != sizeof(fds)) {
 320                         lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 321                         return ret;
 322                 }
 323
 324                 DBG("consumer_add_channel %d", msg.u.channel.channel_key);
 325
 326                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 327                                 fds[0], -1,
 328                                 msg.u.channel.mmap_len,
 329                                 msg.u.channel.max_sb_size);
 330                 if (new_channel == NULL) {
 331                         lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 332                         goto end_nosignal;
 333                 }
 334                 if (ctx->on_recv_channel != NULL) {
 335                         ret = ctx->on_recv_channel(new_channel);
 336                         if (ret == 0) {
 337                                 consumer_add_channel(new_channel);
 338                         } else if (ret < 0) {
 339                                 goto end_nosignal;
 340                         }
 341                 } else {
 342                         consumer_add_channel(new_channel);
 343                 }
 344                 goto end_nosignal;
 345         }
 346         case LTTNG_CONSUMER_ADD_STREAM:
 347         {
 348                 struct lttng_consumer_stream *new_stream;
 349                 int fds[2];
 350                 size_t nb_fd = 2;
 351                 struct consumer_relayd_sock_pair *relayd = NULL;
 352
 353                 DBG("UST Consumer adding stream");
 354
 355                 /* block */
 356                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 357                         return -EINTR;
 358                 }
 359                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 360                 if (ret != sizeof(fds)) {
 361                         lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 362                         return ret;
 363                 }
 364
 365                 DBG("consumer_add_stream chan %d stream %d",
 366                                 msg.u.stream.channel_key,
 367                                 msg.u.stream.stream_key);
 368
 369                 assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
 370                 new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
 371                                 msg.u.stream.stream_key,
 372                                 fds[0], fds[1],
 373                                 msg.u.stream.state,
 374                                 msg.u.stream.mmap_len,
 375                                 msg.u.stream.output,
 376                                 msg.u.stream.path_name,
 377                                 msg.u.stream.uid,
 378                                 msg.u.stream.gid,
 379                                 msg.u.stream.net_index,
 380                                 msg.u.stream.metadata_flag);
 381                 if (new_stream == NULL) {
 382                         lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 383                         goto end;
 384                 }
 385
 386                 /* The stream is not metadata. Get relayd reference if exists. */
 387                 relayd = consumer_find_relayd(msg.u.stream.net_index);
 388                 if (relayd != NULL) {
 389                         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
 390                         /* Add stream on the relayd */
 391                         ret = relayd_add_stream(&relayd->control_sock,
 392                                         msg.u.stream.name, msg.u.stream.path_name,
 393                                         &new_stream->relayd_stream_id);
 394                         pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 395                         if (ret < 0) {
 396                                 goto end;
 397                         }
 398                 } else if (msg.u.stream.net_index != -1) {
 399                         ERR("Network sequence index %d unknown. Not adding stream.",
 400                                         msg.u.stream.net_index);
 401                         free(new_stream);
 402                         goto end;
 403                 }
 404
 405                 if (ctx->on_recv_stream != NULL) {
 406                         ret = ctx->on_recv_stream(new_stream);
 407                         if (ret == 0) {
 408                                 consumer_add_stream(new_stream);
 409                         } else if (ret < 0) {
 410                                 goto end;
 411                         }
 412                 } else {
 413                         consumer_add_stream(new_stream);
 414                 }
 415
 416                 DBG("UST consumer_add_stream %s (%d,%d) with relayd id %lu",
 417                                 msg.u.stream.path_name, fds[0], fds[1],
 418                                 new_stream->relayd_stream_id);
 419                 break;
 420         }
 421         case LTTNG_CONSUMER_DESTROY_RELAYD:
 422         {
 423                 struct consumer_relayd_sock_pair *relayd;
 424
 425                 DBG("UST consumer destroying relayd %zu",
 426                                 msg.u.destroy_relayd.net_seq_idx);
 427
 428                 /* Get relayd reference if exists. */
 429                 relayd = consumer_find_relayd(msg.u.destroy_relayd.net_seq_idx);
 430                 if (relayd == NULL) {
 431                         ERR("Unable to find relayd %zu",
 432                                         msg.u.destroy_relayd.net_seq_idx);
 433                 }
 434
 435                 /* Set destroy flag for this object */
 436                 uatomic_set(&relayd->destroy_flag, 1);
 437
 438                 /* Destroy the relayd if refcount is 0 else set the destroy flag. */
 439                 if (uatomic_read(&relayd->refcount) == 0) {
 440                         consumer_destroy_relayd(relayd);
 441                 }
 442                 break;
 443         }
 444         case LTTNG_CONSUMER_UPDATE_STREAM:
 445         {
 446                 return -ENOSYS;
 447 #if 0
 448                 if (ctx->on_update_stream != NULL) {
 449                         ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
 450                         if (ret == 0) {
 451                                 consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
 452                         } else if (ret < 0) {
 453                                 goto end;
 454                         }
 455                 } else {
 456                         consumer_change_stream_state(msg.u.stream.stream_key,
 457                                 msg.u.stream.state);
 458                 }
 459 #endif
 460                 break;
 461         }
 462         default:
 463                 break;
 464         }
 465 end:
 466         /*
 467          * Wake-up the other end by writing a null byte in the pipe
 468          * (non-blocking). Important note: Because writing into the
 469          * pipe is non-blocking (and therefore we allow dropping wakeup
 470          * data, as long as there is wakeup data present in the pipe
 471          * buffer to wake up the other end), the other end should
 472          * perform the following sequence for waiting:
 473          * 1) empty the pipe (reads).
 474          * 2) perform update operation.
 475          * 3) wait on the pipe (poll).
 476          */
 477         do {
 478                 ret = write(ctx->consumer_poll_pipe[1], "", 1);
 479         } while (ret < 0 && errno == EINTR);
 480 end_nosignal:
 481         rcu_read_unlock();
 482         return 0;
 483 }
 484
 485 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
 486 {
 487         struct lttng_ust_object_data obj;
 488
 489         obj.handle = -1;
 490         obj.shm_fd = chan->shm_fd;
 491         obj.wait_fd = chan->wait_fd;
 492         obj.memory_map_size = chan->mmap_len;
 493         chan->handle = ustctl_map_channel(&obj);
 494         if (!chan->handle) {
 495                 return -ENOMEM;
 496         }
 497         chan->wait_fd_is_copy = 1;
 498         chan->shm_fd = -1;
 499
 500         return 0;
 501 }
 502
 503 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
 504 {
 505         ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
 506         stream->hangup_flush_done = 1;
 507 }
 508
 509 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
 510 {
 511         ustctl_unmap_channel(chan->handle);
 512 }
 513
 514 int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
 515 {
 516         struct lttng_ust_object_data obj;
 517         int ret;
 518
 519         obj.handle = -1;
 520         obj.shm_fd = stream->shm_fd;
 521         obj.wait_fd = stream->wait_fd;
 522         obj.memory_map_size = stream->mmap_len;
 523         ret = ustctl_add_stream(stream->chan->handle, &obj);
 524         if (ret)
 525                 return ret;
 526         stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
 527         if (!stream->buf)
 528                 return -EBUSY;
 529         /* ustctl_open_stream_read has closed the shm fd. */
 530         stream->wait_fd_is_copy = 1;
 531         stream->shm_fd = -1;
 532
 533         stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
 534         if (!stream->mmap_base) {
 535                 return -EINVAL;
 536         }
 537
 538         return 0;
 539 }
 540
 541 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
 542 {
 543         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 544 }
 545
 546
 547 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 548                 struct lttng_consumer_local_data *ctx)
 549 {
 550         unsigned long len;
 551         int err;
 552         long ret = 0;
 553         struct lttng_ust_shm_handle *handle;
 554         struct lttng_ust_lib_ring_buffer *buf;
 555         char dummy;
 556         ssize_t readlen;
 557
 558         DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
 559                 stream->wait_fd, stream->key);
 560
 561         /* We can consume the 1 byte written into the wait_fd by UST */
 562         if (!stream->hangup_flush_done) {
 563                 do {
 564                         readlen = read(stream->wait_fd, &dummy, 1);
 565                 } while (readlen == -1 && errno == EINTR);
 566                 if (readlen == -1) {
 567                         ret = readlen;
 568                         goto end;
 569                 }
 570         }
 571
 572         buf = stream->buf;
 573         handle = stream->chan->handle;
 574         /* Get the next subbuffer */
 575         err = ustctl_get_next_subbuf(handle, buf);
 576         if (err != 0) {
 577                 ret = -ret;     /* ustctl_get_next_subbuf returns negative, caller expect positive. */
 578                 /*
 579                  * This is a debug message even for single-threaded consumer,
 580                  * because poll() have more relaxed criterions than get subbuf,
 581                  * so get_subbuf may fail for short race windows where poll()
 582                  * would issue wakeups.
 583                  */
 584                 DBG("Reserving sub buffer failed (everything is normal, "
 585                                 "it is due to concurrency)");
 586                 goto end;
 587         }
 588         assert(stream->output == LTTNG_EVENT_MMAP);
 589         /* read the used subbuffer size */
 590         err = ustctl_get_padded_subbuf_size(handle, buf, &len);
 591         assert(err == 0);
 592         /* write the subbuffer to the tracefile */
 593         ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
 594         if (ret != len) {
 595                 /*
 596                  * display the error but continue processing to try
 597                  * to release the subbuffer
 598                  */
 599                 ERR("Error writing to tracefile");
 600         }
 601         err = ustctl_put_next_subbuf(handle, buf);
 602         assert(err == 0);
 603 end:
 604         return ret;
 605 }
 606
 607 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
 608 {
 609         int ret;
 610
 611         /* Opening the tracefile in write mode */
 612         if (stream->path_name != NULL && stream->net_seq_idx == -1) {
 613                 ret = run_as_open(stream->path_name,
 614                                 O_WRONLY|O_CREAT|O_TRUNC,
 615                                 S_IRWXU|S_IRWXG|S_IRWXO,
 616                                 stream->uid, stream->gid);
 617                 if (ret < 0) {
 618                         ERR("Opening %s", stream->path_name);
 619                         PERROR("open");
 620                         goto error;
 621                 }
 622                 stream->out_fd = ret;
 623         }
 624
 625         /* we return 0 to let the library handle the FD internally */
 626         return 0;
 627
 628 error:
 629         return ret;
 630 }