src/common/ust-consumer/ust-consumer.c

   1 /*
   2  * Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
   3  *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License, version 2 only,
   7  * as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <assert.h>
  21 #include <lttng/ust-ctl.h>
  22 #include <poll.h>
  23 #include <pthread.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <sys/mman.h>
  27 #include <sys/socket.h>
  28 #include <sys/stat.h>
  29 #include <sys/types.h>
  30 #include <inttypes.h>
  31 #include <unistd.h>
  32
  33 #include <common/common.h>
  34 #include <common/sessiond-comm/sessiond-comm.h>
  35 #include <common/relayd/relayd.h>
  36 #include <common/compat/fcntl.h>
  37
  38 #include "ust-consumer.h"
  39
  40 extern struct lttng_consumer_global_data consumer_data;
  41 extern int consumer_poll_timeout;
  42 extern volatile int consumer_quit;
  43
  44 /*
  45  * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
  46  * compiled out, we isolate it in this library.
  47  */
  48 int lttng_ustctl_get_mmap_read_offset(struct lttng_ust_shm_handle *handle,
  49                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *off)
  50 {
  51         return ustctl_get_mmap_read_offset(handle, buf, off);
  52 };
  53
  54 /*
  55  * Take a snapshot for a specific fd
  56  *
  57  * Returns 0 on success, < 0 on error
  58  */
  59 int lttng_ustconsumer_take_snapshot(struct lttng_consumer_local_data *ctx,
  60                 struct lttng_consumer_stream *stream)
  61 {
  62         int ret = 0;
  63
  64         ret = ustctl_snapshot(stream->chan->handle, stream->buf);
  65         if (ret != 0) {
  66                 errno = -ret;
  67                 PERROR("Getting sub-buffer snapshot.");
  68         }
  69
  70         return ret;
  71 }
  72
  73 /*
  74  * Get the produced position
  75  *
  76  * Returns 0 on success, < 0 on error
  77  */
  78 int lttng_ustconsumer_get_produced_snapshot(
  79                 struct lttng_consumer_local_data *ctx,
  80                 struct lttng_consumer_stream *stream,
  81                 unsigned long *pos)
  82 {
  83         int ret;
  84
  85         ret = ustctl_snapshot_get_produced(stream->chan->handle,
  86                         stream->buf, pos);
  87         if (ret != 0) {
  88                 errno = -ret;
  89                 PERROR("kernctl_snapshot_get_produced");
  90         }
  91
  92         return ret;
  93 }
  94
  95 /*
  96  * Receive command from session daemon and process it.
  97  *
  98  * Return 1 on success else a negative value or 0.
  99  */
 100 int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 101                 int sock, struct pollfd *consumer_sockpoll)
 102 {
 103         ssize_t ret;
 104         struct lttcomm_consumer_msg msg;
 105
 106         ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 107         if (ret != sizeof(msg)) {
 108                 DBG("Consumer received unexpected message size %zd (expects %zu)",
 109                         ret, sizeof(msg));
 110                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 111                 return ret;
 112         }
 113         if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
 114                 return -ENOENT;
 115         }
 116
 117         /* relayd needs RCU read-side lock */
 118         rcu_read_lock();
 119
 120         switch (msg.cmd_type) {
 121         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 122         {
 123                 ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
 124                                 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
 125                                 &msg.u.relayd_sock.sock);
 126                 goto end_nosignal;
 127         }
 128         case LTTNG_CONSUMER_ADD_CHANNEL:
 129         {
 130                 struct lttng_consumer_channel *new_channel;
 131                 int fds[1];
 132                 size_t nb_fd = 1;
 133
 134                 DBG("UST Consumer adding channel");
 135
 136                 /* block */
 137                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 138                         rcu_read_unlock();
 139                         return -EINTR;
 140                 }
 141                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 142                 if (ret != sizeof(fds)) {
 143                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 144                         rcu_read_unlock();
 145                         return ret;
 146                 }
 147
 148                 DBG("consumer_add_channel %d", msg.u.channel.channel_key);
 149
 150                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 151                                 fds[0], -1,
 152                                 msg.u.channel.mmap_len,
 153                                 msg.u.channel.max_sb_size,
 154                                 msg.u.channel.nb_init_streams);
 155                 if (new_channel == NULL) {
 156                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 157                         goto end_nosignal;
 158                 }
 159                 if (ctx->on_recv_channel != NULL) {
 160                         ret = ctx->on_recv_channel(new_channel);
 161                         if (ret == 0) {
 162                                 consumer_add_channel(new_channel);
 163                         } else if (ret < 0) {
 164                                 goto end_nosignal;
 165                         }
 166                 } else {
 167                         consumer_add_channel(new_channel);
 168                 }
 169                 goto end_nosignal;
 170         }
 171         case LTTNG_CONSUMER_ADD_STREAM:
 172         {
 173                 struct lttng_consumer_stream *new_stream;
 174                 int fds[2];
 175                 size_t nb_fd = 2;
 176                 struct consumer_relayd_sock_pair *relayd = NULL;
 177                 int alloc_ret = 0;
 178
 179                 DBG("UST Consumer adding stream");
 180
 181                 /* block */
 182                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 183                         rcu_read_unlock();
 184                         return -EINTR;
 185                 }
 186                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 187                 if (ret != sizeof(fds)) {
 188                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 189                         rcu_read_unlock();
 190                         return ret;
 191                 }
 192
 193                 DBG("consumer_add_stream chan %d stream %d",
 194                                 msg.u.stream.channel_key,
 195                                 msg.u.stream.stream_key);
 196
 197                 assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
 198                 new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
 199                                 msg.u.stream.stream_key,
 200                                 fds[0], fds[1],
 201                                 msg.u.stream.state,
 202                                 msg.u.stream.mmap_len,
 203                                 msg.u.stream.output,
 204                                 msg.u.stream.path_name,
 205                                 msg.u.stream.uid,
 206                                 msg.u.stream.gid,
 207                                 msg.u.stream.net_index,
 208                                 msg.u.stream.metadata_flag,
 209                                 &alloc_ret);
 210                 if (new_stream == NULL) {
 211                         switch (alloc_ret) {
 212                         case -ENOMEM:
 213                         case -EINVAL:
 214                         default:
 215                                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 216                                 break;
 217                         case -ENOENT:
 218                                 /*
 219                                  * We could not find the channel. Can happen if cpu hotplug
 220                                  * happens while tearing down.
 221                                  */
 222                                 DBG3("Could not find channel");
 223                                 break;
 224                         }
 225                         goto end_nosignal;
 226                 }
 227
 228                 /* The stream is not metadata. Get relayd reference if exists. */
 229                 relayd = consumer_find_relayd(msg.u.stream.net_index);
 230                 if (relayd != NULL) {
 231                         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
 232                         /* Add stream on the relayd */
 233                         ret = relayd_add_stream(&relayd->control_sock,
 234                                         msg.u.stream.name, msg.u.stream.path_name,
 235                                         &new_stream->relayd_stream_id);
 236                         pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 237                         if (ret < 0) {
 238                                 goto end_nosignal;
 239                         }
 240                 } else if (msg.u.stream.net_index != -1) {
 241                         ERR("Network sequence index %d unknown. Not adding stream.",
 242                                         msg.u.stream.net_index);
 243                         free(new_stream);
 244                         goto end_nosignal;
 245                 }
 246
 247                 /* Do actions once stream has been received. */
 248                 if (ctx->on_recv_stream) {
 249                         ret = ctx->on_recv_stream(new_stream);
 250                         if (ret < 0) {
 251                                 goto end_nosignal;
 252                         }
 253                 }
 254
 255                 /* Send stream to the metadata thread */
 256                 if (new_stream->metadata_flag) {
 257                         do {
 258                                 ret = write(ctx->consumer_metadata_pipe[1], &new_stream,
 259                                                 sizeof(new_stream));
 260                         } while (ret < 0 && errno == EINTR);
 261                         if (ret < 0) {
 262                                 PERROR("write metadata pipe");
 263                         }
 264                 } else {
 265                         consumer_add_stream(new_stream);
 266                 }
 267
 268                 DBG("UST consumer_add_stream %s (%d,%d) with relayd id %" PRIu64,
 269                                 msg.u.stream.path_name, fds[0], fds[1],
 270                                 new_stream->relayd_stream_id);
 271                 break;
 272         }
 273         case LTTNG_CONSUMER_DESTROY_RELAYD:
 274         {
 275                 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
 276                 struct consumer_relayd_sock_pair *relayd;
 277
 278                 DBG("UST consumer destroying relayd %" PRIu64, index);
 279
 280                 /* Get relayd reference if exists. */
 281                 relayd = consumer_find_relayd(index);
 282                 if (relayd == NULL) {
 283                         ERR("Unable to find relayd %" PRIu64, index);
 284                         goto end_nosignal;
 285                 }
 286
 287                 /*
 288                  * Each relayd socket pair has a refcount of stream attached to it
 289                  * which tells if the relayd is still active or not depending on the
 290                  * refcount value.
 291                  *
 292                  * This will set the destroy flag of the relayd object and destroy it
 293                  * if the refcount reaches zero when called.
 294                  *
 295                  * The destroy can happen either here or when a stream fd hangs up.
 296                  */
 297                 consumer_flag_relayd_for_destroy(relayd);
 298
 299                 goto end_nosignal;
 300         }
 301         case LTTNG_CONSUMER_UPDATE_STREAM:
 302         {
 303                 rcu_read_unlock();
 304                 return -ENOSYS;
 305 #if 0
 306                 if (ctx->on_update_stream != NULL) {
 307                         ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
 308                         if (ret == 0) {
 309                                 consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
 310                         } else if (ret < 0) {
 311                                 goto end;
 312                         }
 313                 } else {
 314                         consumer_change_stream_state(msg.u.stream.stream_key,
 315                                 msg.u.stream.state);
 316                 }
 317                 break;
 318 #endif
 319         }
 320         default:
 321                 break;
 322         }
 323
 324         /*
 325          * Wake-up the other end by writing a null byte in the pipe (non-blocking).
 326          * Important note: Because writing into the pipe is non-blocking (and
 327          * therefore we allow dropping wakeup data, as long as there is wakeup data
 328          * present in the pipe buffer to wake up the other end), the other end
 329          * should perform the following sequence for waiting:
 330          *
 331          * 1) empty the pipe (reads).
 332          * 2) perform update operation.
 333          * 3) wait on the pipe (poll).
 334          */
 335         do {
 336                 ret = write(ctx->consumer_poll_pipe[1], "", 1);
 337         } while (ret < 0 && errno == EINTR);
 338 end_nosignal:
 339         rcu_read_unlock();
 340
 341         /*
 342          * Return 1 to indicate success since the 0 value can be a socket
 343          * shutdown during the recv() or send() call.
 344          */
 345         return 1;
 346 }
 347
 348 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
 349 {
 350         struct lttng_ust_object_data obj;
 351
 352         obj.handle = -1;
 353         obj.shm_fd = chan->shm_fd;
 354         obj.wait_fd = chan->wait_fd;
 355         obj.memory_map_size = chan->mmap_len;
 356         chan->handle = ustctl_map_channel(&obj);
 357         if (!chan->handle) {
 358                 return -ENOMEM;
 359         }
 360         chan->wait_fd_is_copy = 1;
 361         chan->shm_fd = -1;
 362
 363         return 0;
 364 }
 365
 366 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
 367 {
 368         ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
 369         stream->hangup_flush_done = 1;
 370 }
 371
 372 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
 373 {
 374         ustctl_unmap_channel(chan->handle);
 375 }
 376
 377 int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
 378 {
 379         struct lttng_ust_object_data obj;
 380         int ret;
 381
 382         obj.handle = -1;
 383         obj.shm_fd = stream->shm_fd;
 384         obj.wait_fd = stream->wait_fd;
 385         obj.memory_map_size = stream->mmap_len;
 386         ret = ustctl_add_stream(stream->chan->handle, &obj);
 387         if (ret)
 388                 return ret;
 389         stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
 390         if (!stream->buf)
 391                 return -EBUSY;
 392         /* ustctl_open_stream_read has closed the shm fd. */
 393         stream->wait_fd_is_copy = 1;
 394         stream->shm_fd = -1;
 395
 396         stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
 397         if (!stream->mmap_base) {
 398                 return -EINVAL;
 399         }
 400
 401         return 0;
 402 }
 403
 404 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
 405 {
 406         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 407 }
 408
 409
 410 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 411                 struct lttng_consumer_local_data *ctx)
 412 {
 413         unsigned long len, subbuf_size, padding;
 414         int err;
 415         long ret = 0;
 416         struct lttng_ust_shm_handle *handle;
 417         struct lttng_ust_lib_ring_buffer *buf;
 418         char dummy;
 419         ssize_t readlen;
 420
 421         DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
 422                 stream->wait_fd, stream->key);
 423
 424         /* We can consume the 1 byte written into the wait_fd by UST */
 425         if (!stream->hangup_flush_done) {
 426                 do {
 427                         readlen = read(stream->wait_fd, &dummy, 1);
 428                 } while (readlen == -1 && errno == EINTR);
 429                 if (readlen == -1) {
 430                         ret = readlen;
 431                         goto end;
 432                 }
 433         }
 434
 435         buf = stream->buf;
 436         handle = stream->chan->handle;
 437         /* Get the next subbuffer */
 438         err = ustctl_get_next_subbuf(handle, buf);
 439         if (err != 0) {
 440                 ret = err;      /* ustctl_get_next_subbuf returns negative, caller expect positive. */
 441                 /*
 442                  * This is a debug message even for single-threaded consumer,
 443                  * because poll() have more relaxed criterions than get subbuf,
 444                  * so get_subbuf may fail for short race windows where poll()
 445                  * would issue wakeups.
 446                  */
 447                 DBG("Reserving sub buffer failed (everything is normal, "
 448                                 "it is due to concurrency)");
 449                 goto end;
 450         }
 451         assert(stream->output == LTTNG_EVENT_MMAP);
 452         /* Get the full padded subbuffer size */
 453         err = ustctl_get_padded_subbuf_size(handle, buf, &len);
 454         assert(err == 0);
 455
 456         /* Get subbuffer data size (without padding) */
 457         err = ustctl_get_subbuf_size(handle, buf, &subbuf_size);
 458         assert(err == 0);
 459
 460         /* Make sure we don't get a subbuffer size bigger than the padded */
 461         assert(len >= subbuf_size);
 462
 463         padding = len - subbuf_size;
 464         /* write the subbuffer to the tracefile */
 465         ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size, padding);
 466         /*
 467          * The mmap operation should write subbuf_size amount of data when network
 468          * streaming or the full padding (len) size when we are _not_ streaming.
 469          */
 470         if ((ret != subbuf_size && stream->net_seq_idx != -1) ||
 471                         (ret != len && stream->net_seq_idx == -1)) {
 472                 /*
 473                  * Display the error but continue processing to try to release the
 474                  * subbuffer
 475                  */
 476                 ERR("Error writing to tracefile "
 477                                 "(ret: %zd != len: %lu != subbuf_size: %lu)",
 478                                 ret, len, subbuf_size);
 479         }
 480         err = ustctl_put_next_subbuf(handle, buf);
 481         assert(err == 0);
 482 end:
 483         return ret;
 484 }
 485
 486 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
 487 {
 488         int ret;
 489
 490         /* Opening the tracefile in write mode */
 491         if (stream->path_name != NULL && stream->net_seq_idx == -1) {
 492                 ret = run_as_open(stream->path_name,
 493                                 O_WRONLY|O_CREAT|O_TRUNC,
 494                                 S_IRWXU|S_IRWXG|S_IRWXO,
 495                                 stream->uid, stream->gid);
 496                 if (ret < 0) {
 497                         ERR("Opening %s", stream->path_name);
 498                         PERROR("open");
 499                         goto error;
 500                 }
 501                 stream->out_fd = ret;
 502         }
 503
 504         /* we return 0 to let the library handle the FD internally */
 505         return 0;
 506
 507 error:
 508         return ret;
 509 }