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