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 <unistd.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  * Wrapper over the mmap() read offset from ust-ctl library. Since this can be
  45  * compiled out, we isolate it in this library.
  46  */
  47 int lttng_ustctl_get_mmap_read_offset(struct lttng_ust_shm_handle *handle,
  48                 struct lttng_ust_lib_ring_buffer *buf, unsigned long *off)
  49 {
  50         return ustctl_get_mmap_read_offset(handle, buf, off);
  51 };
  52
  53 /*
  54  * Take a snapshot for a specific fd
  55  *
  56  * Returns 0 on success, < 0 on error
  57  */
  58 int lttng_ustconsumer_take_snapshot(struct lttng_consumer_local_data *ctx,
  59                 struct lttng_consumer_stream *stream)
  60 {
  61         int ret = 0;
  62
  63         ret = ustctl_snapshot(stream->chan->handle, stream->buf);
  64         if (ret != 0) {
  65                 errno = -ret;
  66                 PERROR("Getting sub-buffer snapshot.");
  67         }
  68
  69         return ret;
  70 }
  71
  72 /*
  73  * Get the produced position
  74  *
  75  * Returns 0 on success, < 0 on error
  76  */
  77 int lttng_ustconsumer_get_produced_snapshot(
  78                 struct lttng_consumer_local_data *ctx,
  79                 struct lttng_consumer_stream *stream,
  80                 unsigned long *pos)
  81 {
  82         int ret;
  83
  84         ret = ustctl_snapshot_get_produced(stream->chan->handle,
  85                         stream->buf, pos);
  86         if (ret != 0) {
  87                 errno = -ret;
  88                 PERROR("kernctl_snapshot_get_produced");
  89         }
  90
  91         return ret;
  92 }
  93
  94 int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
  95                 int sock, struct pollfd *consumer_sockpoll)
  96 {
  97         ssize_t ret;
  98         struct lttcomm_consumer_msg msg;
  99
 100         ret = lttcomm_recv_unix_sock(sock, &msg, sizeof(msg));
 101         if (ret != sizeof(msg)) {
 102                 DBG("Consumer received unexpected message size %zd (expects %zu)",
 103                         ret, sizeof(msg));
 104                 lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 105                 return ret;
 106         }
 107         if (msg.cmd_type == LTTNG_CONSUMER_STOP) {
 108                 return -ENOENT;
 109         }
 110
 111         /* relayd needs RCU read-side lock */
 112         rcu_read_lock();
 113
 114         switch (msg.cmd_type) {
 115         case LTTNG_CONSUMER_ADD_RELAYD_SOCKET:
 116         {
 117                 int fd;
 118                 struct consumer_relayd_sock_pair *relayd;
 119
 120                 DBG("UST Consumer adding relayd socket");
 121
 122                 /* Get relayd reference if exists. */
 123                 relayd = consumer_find_relayd(msg.u.relayd_sock.net_index);
 124                 if (relayd == NULL) {
 125                         /* Not found. Allocate one. */
 126                         relayd = consumer_allocate_relayd_sock_pair(
 127                                         msg.u.relayd_sock.net_index);
 128                         if (relayd == NULL) {
 129                                 lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 130                                 goto end_nosignal;
 131                         }
 132                 }
 133
 134                 /* Poll on consumer socket. */
 135                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 136                         rcu_read_unlock();
 137                         return -EINTR;
 138                 }
 139
 140                 /* Get relayd socket from session daemon */
 141                 ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
 142                 if (ret != sizeof(fd)) {
 143                         lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 144                         goto end_nosignal;
 145                 }
 146
 147                 /* Copy socket information and received FD */
 148                 switch (msg.u.relayd_sock.type) {
 149                 case LTTNG_STREAM_CONTROL:
 150                         /* Copy received lttcomm socket */
 151                         lttcomm_copy_sock(&relayd->control_sock, &msg.u.relayd_sock.sock);
 152                         ret = lttcomm_create_sock(&relayd->control_sock);
 153                         if (ret < 0) {
 154                                 goto end_nosignal;
 155                         }
 156
 157                         /* Close the created socket fd which is useless */
 158                         close(relayd->control_sock.fd);
 159
 160                         /* Assign new file descriptor */
 161                         relayd->control_sock.fd = fd;
 162                         break;
 163                 case LTTNG_STREAM_DATA:
 164                         /* Copy received lttcomm socket */
 165                         lttcomm_copy_sock(&relayd->data_sock, &msg.u.relayd_sock.sock);
 166                         ret = lttcomm_create_sock(&relayd->data_sock);
 167                         if (ret < 0) {
 168                                 goto end_nosignal;
 169                         }
 170
 171                         /* Close the created socket fd which is useless */
 172                         close(relayd->data_sock.fd);
 173
 174                         /* Assign new file descriptor */
 175                         relayd->data_sock.fd = fd;
 176                         break;
 177                 default:
 178                         ERR("Unknown relayd socket type");
 179                         goto end_nosignal;
 180                 }
 181
 182                 DBG("Consumer %s socket created successfully with net idx %d (fd: %d)",
 183                                 msg.u.relayd_sock.type == LTTNG_STREAM_CONTROL ? "control" : "data",
 184                                 relayd->net_seq_idx, fd);
 185
 186                 /*
 187                  * Add relayd socket pair to consumer data hashtable. If object already
 188                  * exists or on error, the function gracefully returns.
 189                  */
 190                 consumer_add_relayd(relayd);
 191
 192                 goto end_nosignal;
 193         }
 194         case LTTNG_CONSUMER_ADD_CHANNEL:
 195         {
 196                 struct lttng_consumer_channel *new_channel;
 197                 int fds[1];
 198                 size_t nb_fd = 1;
 199
 200                 DBG("UST Consumer adding channel");
 201
 202                 /* block */
 203                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 204                         rcu_read_unlock();
 205                         return -EINTR;
 206                 }
 207                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 208                 if (ret != sizeof(fds)) {
 209                         lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 210                         rcu_read_unlock();
 211                         return ret;
 212                 }
 213
 214                 DBG("consumer_add_channel %d", msg.u.channel.channel_key);
 215
 216                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 217                                 fds[0], -1,
 218                                 msg.u.channel.mmap_len,
 219                                 msg.u.channel.max_sb_size);
 220                 if (new_channel == NULL) {
 221                         lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 222                         goto end_nosignal;
 223                 }
 224                 if (ctx->on_recv_channel != NULL) {
 225                         ret = ctx->on_recv_channel(new_channel);
 226                         if (ret == 0) {
 227                                 consumer_add_channel(new_channel);
 228                         } else if (ret < 0) {
 229                                 goto end_nosignal;
 230                         }
 231                 } else {
 232                         consumer_add_channel(new_channel);
 233                 }
 234                 goto end_nosignal;
 235         }
 236         case LTTNG_CONSUMER_ADD_STREAM:
 237         {
 238                 struct lttng_consumer_stream *new_stream;
 239                 int fds[2];
 240                 size_t nb_fd = 2;
 241                 struct consumer_relayd_sock_pair *relayd = NULL;
 242
 243                 DBG("UST Consumer adding stream");
 244
 245                 /* block */
 246                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 247                         rcu_read_unlock();
 248                         return -EINTR;
 249                 }
 250                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 251                 if (ret != sizeof(fds)) {
 252                         lttng_consumer_send_error(ctx, CONSUMERD_ERROR_RECV_FD);
 253                         rcu_read_unlock();
 254                         return ret;
 255                 }
 256
 257                 DBG("consumer_add_stream chan %d stream %d",
 258                                 msg.u.stream.channel_key,
 259                                 msg.u.stream.stream_key);
 260
 261                 assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
 262                 new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
 263                                 msg.u.stream.stream_key,
 264                                 fds[0], fds[1],
 265                                 msg.u.stream.state,
 266                                 msg.u.stream.mmap_len,
 267                                 msg.u.stream.output,
 268                                 msg.u.stream.path_name,
 269                                 msg.u.stream.uid,
 270                                 msg.u.stream.gid,
 271                                 msg.u.stream.net_index,
 272                                 msg.u.stream.metadata_flag);
 273                 if (new_stream == NULL) {
 274                         lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
 275                         goto end_nosignal;
 276                 }
 277
 278                 /* The stream is not metadata. Get relayd reference if exists. */
 279                 relayd = consumer_find_relayd(msg.u.stream.net_index);
 280                 if (relayd != NULL) {
 281                         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
 282                         /* Add stream on the relayd */
 283                         ret = relayd_add_stream(&relayd->control_sock,
 284                                         msg.u.stream.name, msg.u.stream.path_name,
 285                                         &new_stream->relayd_stream_id);
 286                         pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 287                         if (ret < 0) {
 288                                 goto end_nosignal;
 289                         }
 290                 } else if (msg.u.stream.net_index != -1) {
 291                         ERR("Network sequence index %d unknown. Not adding stream.",
 292                                         msg.u.stream.net_index);
 293                         free(new_stream);
 294                         goto end_nosignal;
 295                 }
 296
 297                 if (ctx->on_recv_stream != NULL) {
 298                         ret = ctx->on_recv_stream(new_stream);
 299                         if (ret == 0) {
 300                                 consumer_add_stream(new_stream);
 301                         } else if (ret < 0) {
 302                                 goto end_nosignal;
 303                         }
 304                 } else {
 305                         consumer_add_stream(new_stream);
 306                 }
 307
 308                 DBG("UST consumer_add_stream %s (%d,%d) with relayd id %lu",
 309                                 msg.u.stream.path_name, fds[0], fds[1],
 310                                 new_stream->relayd_stream_id);
 311                 break;
 312         }
 313         case LTTNG_CONSUMER_DESTROY_RELAYD:
 314         {
 315                 struct consumer_relayd_sock_pair *relayd;
 316
 317                 DBG("UST consumer destroying relayd %zu",
 318                                 msg.u.destroy_relayd.net_seq_idx);
 319
 320                 /* Get relayd reference if exists. */
 321                 relayd = consumer_find_relayd(msg.u.destroy_relayd.net_seq_idx);
 322                 if (relayd == NULL) {
 323                         ERR("Unable to find relayd %zu", msg.u.destroy_relayd.net_seq_idx);
 324                         goto end_nosignal;
 325                 }
 326
 327                 /* Set destroy flag for this object */
 328                 uatomic_set(&relayd->destroy_flag, 1);
 329
 330                 /* Destroy the relayd if refcount is 0 else set the destroy flag. */
 331                 if (uatomic_read(&relayd->refcount) == 0) {
 332                         consumer_destroy_relayd(relayd);
 333                 }
 334                 goto end_nosignal;
 335         }
 336         case LTTNG_CONSUMER_UPDATE_STREAM:
 337         {
 338                 rcu_read_unlock();
 339                 return -ENOSYS;
 340 #if 0
 341                 if (ctx->on_update_stream != NULL) {
 342                         ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
 343                         if (ret == 0) {
 344                                 consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
 345                         } else if (ret < 0) {
 346                                 goto end;
 347                         }
 348                 } else {
 349                         consumer_change_stream_state(msg.u.stream.stream_key,
 350                                 msg.u.stream.state);
 351                 }
 352                 break;
 353 #endif
 354         }
 355         default:
 356                 break;
 357         }
 358
 359         /*
 360          * Wake-up the other end by writing a null byte in the pipe (non-blocking).
 361          * Important note: Because writing into the pipe is non-blocking (and
 362          * therefore we allow dropping wakeup data, as long as there is wakeup data
 363          * present in the pipe buffer to wake up the other end), the other end
 364          * should perform the following sequence for waiting:
 365          *
 366          * 1) empty the pipe (reads).
 367          * 2) perform update operation.
 368          * 3) wait on the pipe (poll).
 369          */
 370         do {
 371                 ret = write(ctx->consumer_poll_pipe[1], "", 1);
 372         } while (ret < 0 && errno == EINTR);
 373 end_nosignal:
 374         rcu_read_unlock();
 375         return 0;
 376 }
 377
 378 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
 379 {
 380         struct lttng_ust_object_data obj;
 381
 382         obj.handle = -1;
 383         obj.shm_fd = chan->shm_fd;
 384         obj.wait_fd = chan->wait_fd;
 385         obj.memory_map_size = chan->mmap_len;
 386         chan->handle = ustctl_map_channel(&obj);
 387         if (!chan->handle) {
 388                 return -ENOMEM;
 389         }
 390         chan->wait_fd_is_copy = 1;
 391         chan->shm_fd = -1;
 392
 393         return 0;
 394 }
 395
 396 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
 397 {
 398         ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
 399         stream->hangup_flush_done = 1;
 400 }
 401
 402 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
 403 {
 404         ustctl_unmap_channel(chan->handle);
 405 }
 406
 407 int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
 408 {
 409         struct lttng_ust_object_data obj;
 410         int ret;
 411
 412         obj.handle = -1;
 413         obj.shm_fd = stream->shm_fd;
 414         obj.wait_fd = stream->wait_fd;
 415         obj.memory_map_size = stream->mmap_len;
 416         ret = ustctl_add_stream(stream->chan->handle, &obj);
 417         if (ret)
 418                 return ret;
 419         stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
 420         if (!stream->buf)
 421                 return -EBUSY;
 422         /* ustctl_open_stream_read has closed the shm fd. */
 423         stream->wait_fd_is_copy = 1;
 424         stream->shm_fd = -1;
 425
 426         stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
 427         if (!stream->mmap_base) {
 428                 return -EINVAL;
 429         }
 430
 431         return 0;
 432 }
 433
 434 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
 435 {
 436         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 437 }
 438
 439
 440 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 441                 struct lttng_consumer_local_data *ctx)
 442 {
 443         unsigned long len;
 444         int err;
 445         long ret = 0;
 446         struct lttng_ust_shm_handle *handle;
 447         struct lttng_ust_lib_ring_buffer *buf;
 448         char dummy;
 449         ssize_t readlen;
 450
 451         DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
 452                 stream->wait_fd, stream->key);
 453
 454         /* We can consume the 1 byte written into the wait_fd by UST */
 455         if (!stream->hangup_flush_done) {
 456                 do {
 457                         readlen = read(stream->wait_fd, &dummy, 1);
 458                 } while (readlen == -1 && errno == EINTR);
 459                 if (readlen == -1) {
 460                         ret = readlen;
 461                         goto end;
 462                 }
 463         }
 464
 465         buf = stream->buf;
 466         handle = stream->chan->handle;
 467         /* Get the next subbuffer */
 468         err = ustctl_get_next_subbuf(handle, buf);
 469         if (err != 0) {
 470                 ret = -ret;     /* ustctl_get_next_subbuf returns negative, caller expect positive. */
 471                 /*
 472                  * This is a debug message even for single-threaded consumer,
 473                  * because poll() have more relaxed criterions than get subbuf,
 474                  * so get_subbuf may fail for short race windows where poll()
 475                  * would issue wakeups.
 476                  */
 477                 DBG("Reserving sub buffer failed (everything is normal, "
 478                                 "it is due to concurrency)");
 479                 goto end;
 480         }
 481         assert(stream->output == LTTNG_EVENT_MMAP);
 482         /* read the used subbuffer size */
 483         err = ustctl_get_padded_subbuf_size(handle, buf, &len);
 484         assert(err == 0);
 485         /* write the subbuffer to the tracefile */
 486         ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
 487         if (ret != len) {
 488                 /*
 489                  * display the error but continue processing to try
 490                  * to release the subbuffer
 491                  */
 492                 ERR("Error writing to tracefile (expected: %ld, got: %ld)", ret, len);
 493         }
 494         err = ustctl_put_next_subbuf(handle, buf);
 495         assert(err == 0);
 496 end:
 497         return ret;
 498 }
 499
 500 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
 501 {
 502         int ret;
 503
 504         /* Opening the tracefile in write mode */
 505         if (stream->path_name != NULL && stream->net_seq_idx == -1) {
 506                 ret = run_as_open(stream->path_name,
 507                                 O_WRONLY|O_CREAT|O_TRUNC,
 508                                 S_IRWXU|S_IRWXG|S_IRWXO,
 509                                 stream->uid, stream->gid);
 510                 if (ret < 0) {
 511                         ERR("Opening %s", stream->path_name);
 512                         PERROR("open");
 513                         goto error;
 514                 }
 515                 stream->out_fd = ret;
 516         }
 517
 518         /* we return 0 to let the library handle the FD internally */
 519         return 0;
 520
 521 error:
 522         return ret;
 523 }