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