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                 lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 216                 return ret;
 217         }
 218         if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
 219                 return -ENOENT;
 220         }
 221
 222         /* relayd need RCU read-side lock */
 223         rcu_read_lock();
 224
 225         switch (msg.cmd_type) {
 226         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 227         {
 228                 int fd;
 229                 struct consumer_relayd_sock_pair *relayd;
 230
 231                 DBG("UST Consumer adding relayd socket");
 232
 233                 /* Get relayd reference if exists. */
 234                 relayd = consumer_find_relayd(msg.u.relayd_sock.net_index);
 235                 if (relayd == NULL) {
 236                         /* Not found. Allocate one. */
 237                         relayd = consumer_allocate_relayd_sock_pair(
 238                                         msg.u.relayd_sock.net_index);
 239                         if (relayd == NULL) {
 240                                 lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 241                                 goto end_nosignal;
 242                         }
 243                 }
 244
 245                 /* Poll on consumer socket. */
 246                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 247                         return -EINTR;
 248                 }
 249
 250                 /* Get relayd socket from session daemon */
 251                 ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
 252                 if (ret != sizeof(fd)) {
 253                         lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 254                         goto end_nosignal;
 255                 }
 256
 257                 /* Copy socket information and received FD */
 258                 switch (msg.u.relayd_sock.type) {
 259                 case LTTNG_STREAM_CONTROL:
 260                         /* Copy received lttcomm socket */
 261                         lttcomm_copy_sock(&relayd->control_sock, &msg.u.relayd_sock.sock);
 262                         ret = lttcomm_create_sock(&relayd->control_sock);
 263                         if (ret < 0) {
 264                                 goto end_nosignal;
 265                         }
 266
 267                         /* Close the created socket fd which is useless */
 268                         close(relayd->control_sock.fd);
 269
 270                         /* Assign new file descriptor */
 271                         relayd->control_sock.fd = fd;
 272                         break;
 273                 case LTTNG_STREAM_DATA:
 274                         /* Copy received lttcomm socket */
 275                         lttcomm_copy_sock(&relayd->data_sock, &msg.u.relayd_sock.sock);
 276                         ret = lttcomm_create_sock(&relayd->data_sock);
 277                         if (ret < 0) {
 278                                 goto end_nosignal;
 279                         }
 280
 281                         /* Close the created socket fd which is useless */
 282                         close(relayd->data_sock.fd);
 283
 284                         /* Assign new file descriptor */
 285                         relayd->data_sock.fd = fd;
 286                         break;
 287                 default:
 288                         ERR("Unknown relayd socket type");
 289                         goto end_nosignal;
 290                 }
 291
 292                 DBG("Consumer %s socket created successfully with net idx %d (fd: %d)",
 293                                 msg.u.relayd_sock.type == LTTNG_STREAM_CONTROL ? "control" : "data",
 294                                 relayd->net_seq_idx, fd);
 295
 296                 /*
 297                  * Add relayd socket pair to consumer data hashtable. If object already
 298                  * exists or on error, the function gracefully returns.
 299                  */
 300                 consumer_add_relayd(relayd);
 301
 302                 goto end_nosignal;
 303         }
 304         case LTTNG_CONSUMER_ADD_CHANNEL:
 305         {
 306                 struct lttng_consumer_channel *new_channel;
 307                 int fds[1];
 308                 size_t nb_fd = 1;
 309
 310                 /* block */
 311                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 312                         return -EINTR;
 313                 }
 314                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 315                 if (ret != sizeof(fds)) {
 316                         lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 317                         return ret;
 318                 }
 319
 320                 DBG("consumer_add_channel %d", msg.u.channel.channel_key);
 321
 322                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 323                                 fds[0], -1,
 324                                 msg.u.channel.mmap_len,
 325                                 msg.u.channel.max_sb_size);
 326                 if (new_channel == NULL) {
 327                         lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 328                         goto end_nosignal;
 329                 }
 330                 if (ctx->on_recv_channel != NULL) {
 331                         ret = ctx->on_recv_channel(new_channel);
 332                         if (ret == 0) {
 333                                 consumer_add_channel(new_channel);
 334                         } else if (ret < 0) {
 335                                 goto end_nosignal;
 336                         }
 337                 } else {
 338                         consumer_add_channel(new_channel);
 339                 }
 340                 goto end_nosignal;
 341         }
 342         case LTTNG_CONSUMER_ADD_STREAM:
 343         {
 344                 struct lttng_consumer_stream *new_stream;
 345                 int fds[2];
 346                 size_t nb_fd = 2;
 347                 struct consumer_relayd_sock_pair *relayd = NULL;
 348
 349                 /* block */
 350                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 351                         return -EINTR;
 352                 }
 353                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 354                 if (ret != sizeof(fds)) {
 355                         lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 356                         return ret;
 357                 }
 358
 359                 assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
 360                 new_stream = consumer_allocate_stream(msg.u.channel.channel_key,
 361                                 msg.u.stream.stream_key,
 362                                 fds[0], fds[1],
 363                                 msg.u.stream.state,
 364                                 msg.u.stream.mmap_len,
 365                                 msg.u.stream.output,
 366                                 msg.u.stream.path_name,
 367                                 msg.u.stream.uid,
 368                                 msg.u.stream.gid,
 369                                 msg.u.stream.net_index,
 370                                 msg.u.stream.metadata_flag);
 371                 if (new_stream == NULL) {
 372                         lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 373                         goto end;
 374                 }
 375
 376                 /* The stream is not metadata. Get relayd reference if exists. */
 377                 relayd = consumer_find_relayd(msg.u.stream.net_index);
 378                 if (relayd != NULL) {
 379                         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
 380                         /* Add stream on the relayd */
 381                         ret = relayd_add_stream(&relayd->control_sock,
 382                                         msg.u.stream.name, msg.u.stream.path_name,
 383                                         &new_stream->relayd_stream_id);
 384                         pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 385                         if (ret < 0) {
 386                                 goto end;
 387                         }
 388                 } else if (msg.u.stream.net_index != -1) {
 389                         ERR("Network sequence index %d unknown. Not adding stream.",
 390                                         msg.u.stream.net_index);
 391                         free(new_stream);
 392                         goto end;
 393                 }
 394
 395                 if (ctx->on_recv_stream != NULL) {
 396                         ret = ctx->on_recv_stream(new_stream);
 397                         if (ret == 0) {
 398                                 consumer_add_stream(new_stream);
 399                         } else if (ret < 0) {
 400                                 goto end;
 401                         }
 402                 } else {
 403                         consumer_add_stream(new_stream);
 404                 }
 405
 406                 DBG("UST consumer_add_stream %s (%d,%d) with relayd id %lu",
 407                                 msg.u.stream.path_name, fds[0], fds[1],
 408                                 new_stream->relayd_stream_id);
 409                 break;
 410         }
 411         case LTTNG_CONSUMER_UPDATE_STREAM:
 412         {
 413                 return -ENOSYS;
 414 #if 0
 415                 if (ctx->on_update_stream != NULL) {
 416                         ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
 417                         if (ret == 0) {
 418                                 consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
 419                         } else if (ret < 0) {
 420                                 goto end;
 421                         }
 422                 } else {
 423                         consumer_change_stream_state(msg.u.stream.stream_key,
 424                                 msg.u.stream.state);
 425                 }
 426 #endif
 427                 break;
 428         }
 429         default:
 430                 break;
 431         }
 432 end:
 433         /*
 434          * Wake-up the other end by writing a null byte in the pipe
 435          * (non-blocking). Important note: Because writing into the
 436          * pipe is non-blocking (and therefore we allow dropping wakeup
 437          * data, as long as there is wakeup data present in the pipe
 438          * buffer to wake up the other end), the other end should
 439          * perform the following sequence for waiting:
 440          * 1) empty the pipe (reads).
 441          * 2) perform update operation.
 442          * 3) wait on the pipe (poll).
 443          */
 444         do {
 445                 ret = write(ctx->consumer_poll_pipe[1], "", 1);
 446         } while (ret < 0 && errno == EINTR);
 447 end_nosignal:
 448         rcu_read_unlock();
 449         return 0;
 450 }
 451
 452 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
 453 {
 454         struct lttng_ust_object_data obj;
 455
 456         obj.handle = -1;
 457         obj.shm_fd = chan->shm_fd;
 458         obj.wait_fd = chan->wait_fd;
 459         obj.memory_map_size = chan->mmap_len;
 460         chan->handle = ustctl_map_channel(&obj);
 461         if (!chan->handle) {
 462                 return -ENOMEM;
 463         }
 464         chan->wait_fd_is_copy = 1;
 465         chan->shm_fd = -1;
 466
 467         return 0;
 468 }
 469
 470 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
 471 {
 472         ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
 473         stream->hangup_flush_done = 1;
 474 }
 475
 476 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
 477 {
 478         ustctl_unmap_channel(chan->handle);
 479 }
 480
 481 int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
 482 {
 483         struct lttng_ust_object_data obj;
 484         int ret;
 485
 486         obj.handle = -1;
 487         obj.shm_fd = stream->shm_fd;
 488         obj.wait_fd = stream->wait_fd;
 489         obj.memory_map_size = stream->mmap_len;
 490         ret = ustctl_add_stream(stream->chan->handle, &obj);
 491         if (ret)
 492                 return ret;
 493         stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
 494         if (!stream->buf)
 495                 return -EBUSY;
 496         /* ustctl_open_stream_read has closed the shm fd. */
 497         stream->wait_fd_is_copy = 1;
 498         stream->shm_fd = -1;
 499
 500         stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
 501         if (!stream->mmap_base) {
 502                 return -EINVAL;
 503         }
 504
 505         return 0;
 506 }
 507
 508 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
 509 {
 510         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 511 }
 512
 513
 514 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 515                 struct lttng_consumer_local_data *ctx)
 516 {
 517         unsigned long len;
 518         int err;
 519         long ret = 0;
 520         struct lttng_ust_shm_handle *handle;
 521         struct lttng_ust_lib_ring_buffer *buf;
 522         char dummy;
 523         ssize_t readlen;
 524
 525         DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
 526                 stream->wait_fd, stream->key);
 527
 528         /* We can consume the 1 byte written into the wait_fd by UST */
 529         if (!stream->hangup_flush_done) {
 530                 do {
 531                         readlen = read(stream->wait_fd, &dummy, 1);
 532                 } while (readlen == -1 && errno == EINTR);
 533                 if (readlen == -1) {
 534                         ret = readlen;
 535                         goto end;
 536                 }
 537         }
 538
 539         buf = stream->buf;
 540         handle = stream->chan->handle;
 541         /* Get the next subbuffer */
 542         err = ustctl_get_next_subbuf(handle, buf);
 543         if (err != 0) {
 544                 ret = -ret;     /* ustctl_get_next_subbuf returns negative, caller expect positive. */
 545                 /*
 546                  * This is a debug message even for single-threaded consumer,
 547                  * because poll() have more relaxed criterions than get subbuf,
 548                  * so get_subbuf may fail for short race windows where poll()
 549                  * would issue wakeups.
 550                  */
 551                 DBG("Reserving sub buffer failed (everything is normal, "
 552                                 "it is due to concurrency)");
 553                 goto end;
 554         }
 555         assert(stream->output == LTTNG_EVENT_MMAP);
 556         /* read the used subbuffer size */
 557         err = ustctl_get_padded_subbuf_size(handle, buf, &len);
 558         assert(err == 0);
 559         /* write the subbuffer to the tracefile */
 560         ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
 561         if (ret != len) {
 562                 /*
 563                  * display the error but continue processing to try
 564                  * to release the subbuffer
 565                  */
 566                 ERR("Error writing to tracefile");
 567         }
 568         err = ustctl_put_next_subbuf(handle, buf);
 569         assert(err == 0);
 570 end:
 571         return ret;
 572 }
 573
 574 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
 575 {
 576         int ret;
 577
 578         /* Opening the tracefile in write mode */
 579         if (stream->path_name != NULL && stream->net_seq_idx == -1) {
 580                 ret = run_as_open(stream->path_name,
 581                                 O_WRONLY|O_CREAT|O_TRUNC,
 582                                 S_IRWXU|S_IRWXG|S_IRWXO,
 583                                 stream->uid, stream->gid);
 584                 if (ret < 0) {
 585                         ERR("Opening %s", stream->path_name);
 586                         PERROR("open");
 587                         goto error;
 588                 }
 589                 stream->out_fd = ret;
 590         }
 591
 592         /* we return 0 to let the library handle the FD internally */
 593         return 0;
 594
 595 error:
 596         return ret;
 597 }