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 int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
  96                 int sock, struct pollfd *consumer_sockpoll)
  97 {
  98         ssize_t ret;
  99         struct lttcomm_consumer_msg msg;
 100
 101         ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 102         if (ret != sizeof(msg)) {
 103                 DBG("Consumer received unexpected message size %zd (expects %zu)",
 104                         ret, sizeof(msg));
 105                 lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 106                 return ret;
 107         }
 108         if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
 109                 return -ENOENT;
 110         }
 111
 112         /* relayd needs RCU read-side lock */
 113         rcu_read_lock();
 114
 115         switch (msg.cmd_type) {
 116         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 117         {
 118                 int fd;
 119                 struct consumer_relayd_sock_pair *relayd;
 120
 121                 DBG("UST Consumer adding relayd socket");
 122
 123                 /* Get relayd reference if exists. */
 124                 relayd = consumer_find_relayd(msg.u.relayd_sock.net_index);
 125                 if (relayd == NULL) {
 126                         /* Not found. Allocate one. */
 127                         relayd = consumer_allocate_relayd_sock_pair(
 128                                         msg.u.relayd_sock.net_index);
 129                         if (relayd == NULL) {
 130                                 lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 131                                 goto end_nosignal;
 132                         }
 133                 }
 134
 135                 /* Poll on consumer socket. */
 136                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 137                         rcu_read_unlock();
 138                         return -EINTR;
 139                 }
 140
 141                 /* Get relayd socket from session daemon */
 142                 ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
 143                 if (ret != sizeof(fd)) {
 144                         lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 145                         goto end_nosignal;
 146                 }
 147
 148                 /* Copy socket information and received FD */
 149                 switch (msg.u.relayd_sock.type) {
 150                 case LTTNG_STREAM_CONTROL:
 151                         /* Copy received lttcomm socket */
 152                         lttcomm_copy_sock(&relayd->control_sock, &msg.u.relayd_sock.sock);
 153                         ret = lttcomm_create_sock(&relayd->control_sock);
 154                         if (ret < 0) {
 155                                 goto end_nosignal;
 156                         }
 157
 158                         /* Close the created socket fd which is useless */
 159                         close(relayd->control_sock.fd);
 160
 161                         /* Assign new file descriptor */
 162                         relayd->control_sock.fd = fd;
 163                         break;
 164                 case LTTNG_STREAM_DATA:
 165                         /* Copy received lttcomm socket */
 166                         lttcomm_copy_sock(&relayd->data_sock, &msg.u.relayd_sock.sock);
 167                         ret = lttcomm_create_sock(&relayd->data_sock);
 168                         if (ret < 0) {
 169                                 goto end_nosignal;
 170                         }
 171
 172                         /* Close the created socket fd which is useless */
 173                         close(relayd->data_sock.fd);
 174
 175                         /* Assign new file descriptor */
 176                         relayd->data_sock.fd = fd;
 177                         break;
 178                 default:
 179                         ERR("Unknown relayd socket type");
 180                         goto end_nosignal;
 181                 }
 182
 183                 DBG("Consumer %s socket created successfully with net idx %d (fd: %d)",
 184                                 msg.u.relayd_sock.type == LTTNG_STREAM_CONTROL ? "control" : "data",
 185                                 relayd->net_seq_idx, fd);
 186
 187                 /*
 188                  * Add relayd socket pair to consumer data hashtable. If object already
 189                  * exists or on error, the function gracefully returns.
 190                  */
 191                 consumer_add_relayd(relayd);
 192
 193                 goto end_nosignal;
 194         }
 195         case LTTNG_CONSUMER_ADD_CHANNEL:
 196         {
 197                 struct lttng_consumer_channel *new_channel;
 198                 int fds[1];
 199                 size_t nb_fd = 1;
 200
 201                 DBG("UST Consumer adding channel");
 202
 203                 /* block */
 204                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 205                         rcu_read_unlock();
 206                         return -EINTR;
 207                 }
 208                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 209                 if (ret != sizeof(fds)) {
 210                         lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 211                         rcu_read_unlock();
 212                         return ret;
 213                 }
 214
 215                 DBG("consumer_add_channel %d", msg.u.channel.channel_key);
 216
 217                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 218                                 fds[0], -1,
 219                                 msg.u.channel.mmap_len,
 220                                 msg.u.channel.max_sb_size);
 221                 if (new_channel == NULL) {
 222                         lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 223                         goto end_nosignal;
 224                 }
 225                 if (ctx->on_recv_channel != NULL) {
 226                         ret = ctx->on_recv_channel(new_channel);
 227                         if (ret == 0) {
 228                                 consumer_add_channel(new_channel);
 229                         } else if (ret < 0) {
 230                                 goto end_nosignal;
 231                         }
 232                 } else {
 233                         consumer_add_channel(new_channel);
 234                 }
 235                 goto end_nosignal;
 236         }
 237         case LTTNG_CONSUMER_ADD_STREAM:
 238         {
 239                 struct lttng_consumer_stream *new_stream;
 240                 int fds[2];
 241                 size_t nb_fd = 2;
 242                 struct consumer_relayd_sock_pair *relayd = NULL;
 243
 244                 DBG("UST Consumer adding stream");
 245
 246                 /* block */
 247                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 248                         rcu_read_unlock();
 249                         return -EINTR;
 250                 }
 251                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 252                 if (ret != sizeof(fds)) {
 253                         lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 254                         rcu_read_unlock();
 255                         return ret;
 256                 }
 257
 258                 DBG("consumer_add_stream chan %d stream %d",
 259                                 msg.u.stream.channel_key,
 260                                 msg.u.stream.stream_key);
 261
 262                 assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
 263                 new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
 264                                 msg.u.stream.stream_key,
 265                                 fds[0], fds[1],
 266                                 msg.u.stream.state,
 267                                 msg.u.stream.mmap_len,
 268                                 msg.u.stream.output,
 269                                 msg.u.stream.path_name,
 270                                 msg.u.stream.uid,
 271                                 msg.u.stream.gid,
 272                                 msg.u.stream.net_index,
 273                                 msg.u.stream.metadata_flag);
 274                 if (new_stream == NULL) {
 275                         lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 276                         goto end_nosignal;
 277                 }
 278
 279                 /* The stream is not metadata. Get relayd reference if exists. */
 280                 relayd = consumer_find_relayd(msg.u.stream.net_index);
 281                 if (relayd != NULL) {
 282                         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
 283                         /* Add stream on the relayd */
 284                         ret = relayd_add_stream(&relayd->control_sock,
 285                                         msg.u.stream.name, msg.u.stream.path_name,
 286                                         &new_stream->relayd_stream_id);
 287                         pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 288                         if (ret < 0) {
 289                                 goto end_nosignal;
 290                         }
 291                 } else if (msg.u.stream.net_index != -1) {
 292                         ERR("Network sequence index %d unknown. Not adding stream.",
 293                                         msg.u.stream.net_index);
 294                         free(new_stream);
 295                         goto end_nosignal;
 296                 }
 297
 298                 if (ctx->on_recv_stream != NULL) {
 299                         ret = ctx->on_recv_stream(new_stream);
 300                         if (ret == 0) {
 301                                 consumer_add_stream(new_stream);
 302                         } else if (ret < 0) {
 303                                 goto end_nosignal;
 304                         }
 305                 } else {
 306                         consumer_add_stream(new_stream);
 307                 }
 308
 309                 DBG("UST consumer_add_stream %s (%d,%d) with relayd id %" PRIu64,
 310                                 msg.u.stream.path_name, fds[0], fds[1],
 311                                 new_stream->relayd_stream_id);
 312                 break;
 313         }
 314         case LTTNG_CONSUMER_DESTROY_RELAYD:
 315         {
 316                 struct consumer_relayd_sock_pair *relayd;
 317
 318                 DBG("UST consumer destroying relayd %" PRIu64,
 319                                 msg.u.destroy_relayd.net_seq_idx);
 320
 321                 /* Get relayd reference if exists. */
 322                 relayd = consumer_find_relayd(msg.u.destroy_relayd.net_seq_idx);
 323                 if (relayd == NULL) {
 324                         ERR("Unable to find relayd %" PRIu64, msg.u.destroy_relayd.net_seq_idx);
 325                         goto end_nosignal;
 326                 }
 327
 328                 /* Set destroy flag for this object */
 329                 uatomic_set(&relayd->destroy_flag, 1);
 330
 331                 /* Destroy the relayd if refcount is 0 else set the destroy flag. */
 332                 if (uatomic_read(&relayd->refcount) == 0) {
 333                         consumer_destroy_relayd(relayd);
 334                 }
 335                 goto end_nosignal;
 336         }
 337         case LTTNG_CONSUMER_UPDATE_STREAM:
 338         {
 339                 rcu_read_unlock();
 340                 return -ENOSYS;
 341 #if 0
 342                 if (ctx->on_update_stream != NULL) {
 343                         ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
 344                         if (ret == 0) {
 345                                 consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
 346                         } else if (ret < 0) {
 347                                 goto end;
 348                         }
 349                 } else {
 350                         consumer_change_stream_state(msg.u.stream.stream_key,
 351                                 msg.u.stream.state);
 352                 }
 353                 break;
 354 #endif
 355         }
 356         default:
 357                 break;
 358         }
 359
 360         /*
 361          * Wake-up the other end by writing a null byte in the pipe (non-blocking).
 362          * Important note: Because writing into the pipe is non-blocking (and
 363          * therefore we allow dropping wakeup data, as long as there is wakeup data
 364          * present in the pipe buffer to wake up the other end), the other end
 365          * should perform the following sequence for waiting:
 366          *
 367          * 1) empty the pipe (reads).
 368          * 2) perform update operation.
 369          * 3) wait on the pipe (poll).
 370          */
 371         do {
 372                 ret = write(ctx->consumer_poll_pipe[1], "", 1);
 373         } while (ret < 0 && errno == EINTR);
 374 end_nosignal:
 375         rcu_read_unlock();
 376         return 0;
 377 }
 378
 379 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
 380 {
 381         struct lttng_ust_object_data obj;
 382
 383         obj.handle = -1;
 384         obj.shm_fd = chan->shm_fd;
 385         obj.wait_fd = chan->wait_fd;
 386         obj.memory_map_size = chan->mmap_len;
 387         chan->handle = ustctl_map_channel(&obj);
 388         if (!chan->handle) {
 389                 return -ENOMEM;
 390         }
 391         chan->wait_fd_is_copy = 1;
 392         chan->shm_fd = -1;
 393
 394         return 0;
 395 }
 396
 397 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
 398 {
 399         ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
 400         stream->hangup_flush_done = 1;
 401 }
 402
 403 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
 404 {
 405         ustctl_unmap_channel(chan->handle);
 406 }
 407
 408 int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
 409 {
 410         struct lttng_ust_object_data obj;
 411         int ret;
 412
 413         obj.handle = -1;
 414         obj.shm_fd = stream->shm_fd;
 415         obj.wait_fd = stream->wait_fd;
 416         obj.memory_map_size = stream->mmap_len;
 417         ret = ustctl_add_stream(stream->chan->handle, &obj);
 418         if (ret)
 419                 return ret;
 420         stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
 421         if (!stream->buf)
 422                 return -EBUSY;
 423         /* ustctl_open_stream_read has closed the shm fd. */
 424         stream->wait_fd_is_copy = 1;
 425         stream->shm_fd = -1;
 426
 427         stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
 428         if (!stream->mmap_base) {
 429                 return -EINVAL;
 430         }
 431
 432         return 0;
 433 }
 434
 435 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
 436 {
 437         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 438 }
 439
 440
 441 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 442                 struct lttng_consumer_local_data *ctx)
 443 {
 444         unsigned long len;
 445         int err;
 446         long ret = 0;
 447         struct lttng_ust_shm_handle *handle;
 448         struct lttng_ust_lib_ring_buffer *buf;
 449         char dummy;
 450         ssize_t readlen;
 451
 452         DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
 453                 stream->wait_fd, stream->key);
 454
 455         /* We can consume the 1 byte written into the wait_fd by UST */
 456         if (!stream->hangup_flush_done) {
 457                 do {
 458                         readlen = read(stream->wait_fd, &dummy, 1);
 459                 } while (readlen == -1 && errno == EINTR);
 460                 if (readlen == -1) {
 461                         ret = readlen;
 462                         goto end;
 463                 }
 464         }
 465
 466         buf = stream->buf;
 467         handle = stream->chan->handle;
 468         /* Get the next subbuffer */
 469         err = ustctl_get_next_subbuf(handle, buf);
 470         if (err != 0) {
 471                 ret = -ret;     /* ustctl_get_next_subbuf returns negative, caller expect positive. */
 472                 /*
 473                  * This is a debug message even for single-threaded consumer,
 474                  * because poll() have more relaxed criterions than get subbuf,
 475                  * so get_subbuf may fail for short race windows where poll()
 476                  * would issue wakeups.
 477                  */
 478                 DBG("Reserving sub buffer failed (everything is normal, "
 479                                 "it is due to concurrency)");
 480                 goto end;
 481         }
 482         assert(stream->output == LTTNG_EVENT_MMAP);
 483         /* read the used subbuffer size */
 484         err = ustctl_get_padded_subbuf_size(handle, buf, &len);
 485         assert(err == 0);
 486         /* write the subbuffer to the tracefile */
 487         ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
 488         if (ret != len) {
 489                 /*
 490                  * display the error but continue processing to try
 491                  * to release the subbuffer
 492                  */
 493                 ERR("Error writing to tracefile (expected: %ld, got: %ld)", ret, len);
 494         }
 495         err = ustctl_put_next_subbuf(handle, buf);
 496         assert(err == 0);
 497 end:
 498         return ret;
 499 }
 500
 501 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
 502 {
 503         int ret;
 504
 505         /* Opening the tracefile in write mode */
 506         if (stream->path_name != NULL && stream->net_seq_idx == -1) {
 507                 ret = run_as_open(stream->path_name,
 508                                 O_WRONLY|O_CREAT|O_TRUNC,
 509                                 S_IRWXU|S_IRWXG|S_IRWXO,
 510                                 stream->uid, stream->gid);
 511                 if (ret < 0) {
 512                         ERR("Opening %s", stream->path_name);
 513                         PERROR("open");
 514                         goto error;
 515                 }
 516                 stream->out_fd = ret;
 517         }
 518
 519         /* we return 0 to let the library handle the FD internally */
 520         return 0;
 521
 522 error:
 523         return ret;
 524 }