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 command ADD_STREAM chan %d stream %d",
 194                                 msg.u.stream.channel_key, msg.u.stream.stream_key);
 195
 196                 assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
 197                 new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
 198                                 msg.u.stream.stream_key,
 199                                 fds[0], fds[1],
 200                                 msg.u.stream.state,
 201                                 msg.u.stream.mmap_len,
 202                                 msg.u.stream.output,
 203                                 msg.u.stream.path_name,
 204                                 msg.u.stream.uid,
 205                                 msg.u.stream.gid,
 206                                 msg.u.stream.net_index,
 207                                 msg.u.stream.metadata_flag,
 208                                 &alloc_ret);
 209                 if (new_stream == NULL) {
 210                         switch (alloc_ret) {
 211                         case -ENOMEM:
 212                         case -EINVAL:
 213                         default:
 214                                 lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 215                                 break;
 216                         case -ENOENT:
 217                                 /*
 218                                  * We could not find the channel. Can happen if cpu hotplug
 219                                  * happens while tearing down.
 220                                  */
 221                                 DBG3("Could not find channel");
 222                                 break;
 223                         }
 224                         goto end_nosignal;
 225                 }
 226
 227                 /* The stream is not metadata. Get relayd reference if exists. */
 228                 relayd = consumer_find_relayd(msg.u.stream.net_index);
 229                 if (relayd != NULL) {
 230                         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
 231                         /* Add stream on the relayd */
 232                         ret = relayd_add_stream(&relayd->control_sock,
 233                                         msg.u.stream.name, msg.u.stream.path_name,
 234                                         &new_stream->relayd_stream_id);
 235                         pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 236                         if (ret < 0) {
 237                                 consumer_del_stream(new_stream, NULL);
 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                         consumer_del_stream(new_stream, NULL);
 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                                 consumer_del_stream(new_stream, NULL);
 252                                 goto end_nosignal;
 253                         }
 254                 }
 255
 256                 /* Send stream to the metadata thread */
 257                 if (new_stream->metadata_flag) {
 258                         do {
 259                                 ret = write(ctx->consumer_metadata_pipe[1], &new_stream,
 260                                                 sizeof(new_stream));
 261                         } while (ret < 0 && errno == EINTR);
 262                         if (ret < 0) {
 263                                 PERROR("write metadata pipe");
 264                                 consumer_del_metadata_stream(new_stream, NULL);
 265                                 goto end_nosignal;
 266                         }
 267                 } else {
 268                         ret = consumer_add_stream(new_stream);
 269                         if (ret) {
 270                                 ERR("Consumer add stream %d failed. Continuing",
 271                                                 new_stream->key);
 272                                 /*
 273                                  * At this point, if the add_stream fails, it is not in the
 274                                  * hash table thus passing the NULL value here.
 275                                  */
 276                                 consumer_del_stream(new_stream, NULL);
 277                                 goto end_nosignal;
 278                         }
 279                 }
 280
 281                 DBG("UST consumer_add_stream %s (%d,%d) with relayd id %" PRIu64,
 282                                 msg.u.stream.path_name, fds[0], fds[1],
 283                                 new_stream->relayd_stream_id);
 284                 break;
 285         }
 286         case LTTNG_CONSUMER_DESTROY_RELAYD:
 287         {
 288                 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
 289                 struct consumer_relayd_sock_pair *relayd;
 290
 291                 DBG("UST consumer destroying relayd %" PRIu64, index);
 292
 293                 /* Get relayd reference if exists. */
 294                 relayd = consumer_find_relayd(index);
 295                 if (relayd == NULL) {
 296                         ERR("Unable to find relayd %" PRIu64, index);
 297                         goto end_nosignal;
 298                 }
 299
 300                 /*
 301                  * Each relayd socket pair has a refcount of stream attached to it
 302                  * which tells if the relayd is still active or not depending on the
 303                  * refcount value.
 304                  *
 305                  * This will set the destroy flag of the relayd object and destroy it
 306                  * if the refcount reaches zero when called.
 307                  *
 308                  * The destroy can happen either here or when a stream fd hangs up.
 309                  */
 310                 consumer_flag_relayd_for_destroy(relayd);
 311
 312                 goto end_nosignal;
 313         }
 314         case LTTNG_CONSUMER_UPDATE_STREAM:
 315         {
 316                 rcu_read_unlock();
 317                 return -ENOSYS;
 318 #if 0
 319                 if (ctx->on_update_stream != NULL) {
 320                         ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
 321                         if (ret == 0) {
 322                                 consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
 323                         } else if (ret < 0) {
 324                                 goto end;
 325                         }
 326                 } else {
 327                         consumer_change_stream_state(msg.u.stream.stream_key,
 328                                 msg.u.stream.state);
 329                 }
 330                 break;
 331 #endif
 332         }
 333         default:
 334                 break;
 335         }
 336
 337         /*
 338          * Wake-up the other end by writing a null byte in the pipe (non-blocking).
 339          * Important note: Because writing into the pipe is non-blocking (and
 340          * therefore we allow dropping wakeup data, as long as there is wakeup data
 341          * present in the pipe buffer to wake up the other end), the other end
 342          * should perform the following sequence for waiting:
 343          *
 344          * 1) empty the pipe (reads).
 345          * 2) perform update operation.
 346          * 3) wait on the pipe (poll).
 347          */
 348         do {
 349                 ret = write(ctx->consumer_poll_pipe[1], "", 1);
 350         } while (ret < 0 && errno == EINTR);
 351 end_nosignal:
 352         rcu_read_unlock();
 353
 354         /*
 355          * Return 1 to indicate success since the 0 value can be a socket
 356          * shutdown during the recv() or send() call.
 357          */
 358         return 1;
 359 }
 360
 361 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
 362 {
 363         struct lttng_ust_object_data obj;
 364
 365         obj.handle = -1;
 366         obj.shm_fd = chan->shm_fd;
 367         obj.wait_fd = chan->wait_fd;
 368         obj.memory_map_size = chan->mmap_len;
 369         chan->handle = ustctl_map_channel(&obj);
 370         if (!chan->handle) {
 371                 return -ENOMEM;
 372         }
 373         chan->wait_fd_is_copy = 1;
 374         chan->shm_fd = -1;
 375
 376         return 0;
 377 }
 378
 379 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
 380 {
 381         ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
 382         stream->hangup_flush_done = 1;
 383 }
 384
 385 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
 386 {
 387         ustctl_unmap_channel(chan->handle);
 388 }
 389
 390 int lttng_ustconsumer_add_stream(struct lttng_consumer_stream *stream)
 391 {
 392         struct lttng_ust_object_data obj;
 393         int ret;
 394
 395         obj.handle = -1;
 396         obj.shm_fd = stream->shm_fd;
 397         obj.wait_fd = stream->wait_fd;
 398         obj.memory_map_size = stream->mmap_len;
 399         ret = ustctl_add_stream(stream->chan->handle, &obj);
 400         if (ret) {
 401                 ERR("UST ctl add_stream failed with ret %d", ret);
 402                 goto error;
 403         }
 404
 405         stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
 406         if (!stream->buf) {
 407                 ERR("UST ctl open_stream_read failed");
 408                 ret = -EBUSY;
 409                 goto error;
 410         }
 411
 412         /* ustctl_open_stream_read has closed the shm fd. */
 413         stream->wait_fd_is_copy = 1;
 414         stream->shm_fd = -1;
 415
 416         stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
 417         if (!stream->mmap_base) {
 418                 ERR("UST ctl get_mmap_base failed");
 419                 ret = -EINVAL;
 420                 goto mmap_error;
 421         }
 422
 423         return 0;
 424
 425 mmap_error:
 426         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 427 error:
 428         return ret;
 429 }
 430
 431 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
 432 {
 433         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 434 }
 435
 436
 437 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 438                 struct lttng_consumer_local_data *ctx)
 439 {
 440         unsigned long len, subbuf_size, padding;
 441         int err;
 442         long ret = 0;
 443         struct lttng_ust_shm_handle *handle;
 444         struct lttng_ust_lib_ring_buffer *buf;
 445         char dummy;
 446         ssize_t readlen;
 447
 448         DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
 449                 stream->wait_fd, stream->key);
 450
 451         /* We can consume the 1 byte written into the wait_fd by UST */
 452         if (!stream->hangup_flush_done) {
 453                 do {
 454                         readlen = read(stream->wait_fd, &dummy, 1);
 455                 } while (readlen == -1 && errno == EINTR);
 456                 if (readlen == -1) {
 457                         ret = readlen;
 458                         goto end;
 459                 }
 460         }
 461
 462         buf = stream->buf;
 463         handle = stream->chan->handle;
 464         /* Get the next subbuffer */
 465         err = ustctl_get_next_subbuf(handle, buf);
 466         if (err != 0) {
 467                 ret = err;      /* ustctl_get_next_subbuf returns negative, caller expect positive. */
 468                 /*
 469                  * This is a debug message even for single-threaded consumer,
 470                  * because poll() have more relaxed criterions than get subbuf,
 471                  * so get_subbuf may fail for short race windows where poll()
 472                  * would issue wakeups.
 473                  */
 474                 DBG("Reserving sub buffer failed (everything is normal, "
 475                                 "it is due to concurrency)");
 476                 goto end;
 477         }
 478         assert(stream->output == LTTNG_EVENT_MMAP);
 479         /* Get the full padded subbuffer size */
 480         err = ustctl_get_padded_subbuf_size(handle, buf, &len);
 481         assert(err == 0);
 482
 483         /* Get subbuffer data size (without padding) */
 484         err = ustctl_get_subbuf_size(handle, buf, &subbuf_size);
 485         assert(err == 0);
 486
 487         /* Make sure we don't get a subbuffer size bigger than the padded */
 488         assert(len >= subbuf_size);
 489
 490         padding = len - subbuf_size;
 491         /* write the subbuffer to the tracefile */
 492         ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size, padding);
 493         /*
 494          * The mmap operation should write subbuf_size amount of data when network
 495          * streaming or the full padding (len) size when we are _not_ streaming.
 496          */
 497         if ((ret != subbuf_size && stream->net_seq_idx != -1) ||
 498                         (ret != len && stream->net_seq_idx == -1)) {
 499                 /*
 500                  * Display the error but continue processing to try to release the
 501                  * subbuffer
 502                  */
 503                 ERR("Error writing to tracefile "
 504                                 "(ret: %zd != len: %lu != subbuf_size: %lu)",
 505                                 ret, len, subbuf_size);
 506         }
 507         err = ustctl_put_next_subbuf(handle, buf);
 508         assert(err == 0);
 509 end:
 510         return ret;
 511 }
 512
 513 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
 514 {
 515         int ret;
 516
 517         /* Opening the tracefile in write mode */
 518         if (stream->path_name != NULL && stream->net_seq_idx == -1) {
 519                 ret = run_as_open(stream->path_name,
 520                                 O_WRONLY|O_CREAT|O_TRUNC,
 521                                 S_IRWXU|S_IRWXG|S_IRWXO,
 522                                 stream->uid, stream->gid);
 523                 if (ret < 0) {
 524                         ERR("Opening %s", stream->path_name);
 525                         PERROR("open");
 526                         goto error;
 527                 }
 528                 stream->out_fd = ret;
 529         }
 530
 531         /* we return 0 to let the library handle the FD internally */
 532         return 0;
 533
 534 error:
 535         return ret;
 536 }