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, LTTCOMM_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                 ret = consumer_add_relayd_socket(msg.u.relayd_sock.net_index,
 119                                 msg.u.relayd_sock.type, ctx, sock, consumer_sockpoll,
 120                                 &msg.u.relayd_sock.sock);
 121                 goto end_nosignal;
 122         }
 123         case LTTNG_CONSUMER_ADD_CHANNEL:
 124         {
 125                 struct lttng_consumer_channel *new_channel;
 126                 int fds[1];
 127                 size_t nb_fd = 1;
 128
 129                 DBG("UST Consumer adding channel");
 130
 131                 /* block */
 132                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 133                         rcu_read_unlock();
 134                         return -EINTR;
 135                 }
 136                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 137                 if (ret != sizeof(fds)) {
 138                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 139                         rcu_read_unlock();
 140                         return ret;
 141                 }
 142
 143                 DBG("consumer_add_channel %d", msg.u.channel.channel_key);
 144
 145                 new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 146                                 fds[0], -1,
 147                                 msg.u.channel.mmap_len,
 148                                 msg.u.channel.max_sb_size);
 149                 if (new_channel == NULL) {
 150                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 151                         goto end_nosignal;
 152                 }
 153                 if (ctx->on_recv_channel != NULL) {
 154                         ret = ctx->on_recv_channel(new_channel);
 155                         if (ret == 0) {
 156                                 consumer_add_channel(new_channel);
 157                         } else if (ret < 0) {
 158                                 goto end_nosignal;
 159                         }
 160                 } else {
 161                         consumer_add_channel(new_channel);
 162                 }
 163                 goto end_nosignal;
 164         }
 165         case LTTNG_CONSUMER_ADD_STREAM:
 166         {
 167                 struct lttng_consumer_stream *new_stream;
 168                 int fds[2];
 169                 size_t nb_fd = 2;
 170                 struct consumer_relayd_sock_pair *relayd = NULL;
 171
 172                 DBG("UST Consumer adding stream");
 173
 174                 /* block */
 175                 if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 176                         rcu_read_unlock();
 177                         return -EINTR;
 178                 }
 179                 ret = lttcomm_recv_fds_unix_sock(sock, fds, nb_fd);
 180                 if (ret != sizeof(fds)) {
 181                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_ERROR_RECV_FD);
 182                         rcu_read_unlock();
 183                         return ret;
 184                 }
 185
 186                 DBG("consumer_add_stream chan %d stream %d",
 187                                 msg.u.stream.channel_key,
 188                                 msg.u.stream.stream_key);
 189
 190                 assert(msg.u.stream.output == LTTNG_EVENT_MMAP);
 191                 new_stream = consumer_allocate_stream(msg.u.stream.channel_key,
 192                                 msg.u.stream.stream_key,
 193                                 fds[0], fds[1],
 194                                 msg.u.stream.state,
 195                                 msg.u.stream.mmap_len,
 196                                 msg.u.stream.output,
 197                                 msg.u.stream.path_name,
 198                                 msg.u.stream.uid,
 199                                 msg.u.stream.gid,
 200                                 msg.u.stream.net_index,
 201                                 msg.u.stream.metadata_flag);
 202                 if (new_stream == NULL) {
 203                         lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 204                         goto end_nosignal;
 205                 }
 206
 207                 /* The stream is not metadata. Get relayd reference if exists. */
 208                 relayd = consumer_find_relayd(msg.u.stream.net_index);
 209                 if (relayd != NULL) {
 210                         pthread_mutex_lock(&relayd->ctrl_sock_mutex);
 211                         /* Add stream on the relayd */
 212                         ret = relayd_add_stream(&relayd->control_sock,
 213                                         msg.u.stream.name, msg.u.stream.path_name,
 214                                         &new_stream->relayd_stream_id);
 215                         pthread_mutex_unlock(&relayd->ctrl_sock_mutex);
 216                         if (ret < 0) {
 217                                 goto end_nosignal;
 218                         }
 219                 } else if (msg.u.stream.net_index != -1) {
 220                         ERR("Network sequence index %d unknown. Not adding stream.",
 221                                         msg.u.stream.net_index);
 222                         free(new_stream);
 223                         goto end_nosignal;
 224                 }
 225
 226                 if (ctx->on_recv_stream != NULL) {
 227                         ret = ctx->on_recv_stream(new_stream);
 228                         if (ret == 0) {
 229                                 consumer_add_stream(new_stream);
 230                         } else if (ret < 0) {
 231                                 goto end_nosignal;
 232                         }
 233                 } else {
 234                         consumer_add_stream(new_stream);
 235                 }
 236
 237                 DBG("UST consumer_add_stream %s (%d,%d) with relayd id %" PRIu64,
 238                                 msg.u.stream.path_name, fds[0], fds[1],
 239                                 new_stream->relayd_stream_id);
 240                 break;
 241         }
 242         case LTTNG_CONSUMER_DESTROY_RELAYD:
 243         {
 244                 uint64_t index = msg.u.destroy_relayd.net_seq_idx;
 245                 struct consumer_relayd_sock_pair *relayd;
 246
 247                 DBG("UST consumer destroying relayd %" PRIu64, index);
 248
 249                 /* Get relayd reference if exists. */
 250                 relayd = consumer_find_relayd(index);
 251                 if (relayd == NULL) {
 252                         ERR("Unable to find relayd %" PRIu64, index);
 253                         goto end_nosignal;
 254                 }
 255
 256                 /*
 257                  * Each relayd socket pair has a refcount of stream attached to it
 258                  * which tells if the relayd is still active or not depending on the
 259                  * refcount value.
 260                  *
 261                  * This will set the destroy flag of the relayd object and destroy it
 262                  * if the refcount reaches zero when called.
 263                  *
 264                  * The destroy can happen either here or when a stream fd hangs up.
 265                  */
 266                 consumer_flag_relayd_for_destroy(relayd);
 267
 268                 goto end_nosignal;
 269         }
 270         case LTTNG_CONSUMER_UPDATE_STREAM:
 271         {
 272                 rcu_read_unlock();
 273                 return -ENOSYS;
 274 #if 0
 275                 if (ctx->on_update_stream != NULL) {
 276                         ret = ctx->on_update_stream(msg.u.stream.stream_key, msg.u.stream.state);
 277                         if (ret == 0) {
 278                                 consumer_change_stream_state(msg.u.stream.stream_key, msg.u.stream.state);
 279                         } else if (ret < 0) {
 280                                 goto end;
 281                         }
 282                 } else {
 283                         consumer_change_stream_state(msg.u.stream.stream_key,
 284                                 msg.u.stream.state);
 285                 }
 286                 break;
 287 #endif
 288         }
 289         default:
 290                 break;
 291         }
 292
 293         /*
 294          * Wake-up the other end by writing a null byte in the pipe (non-blocking).
 295          * Important note: Because writing into the pipe is non-blocking (and
 296          * therefore we allow dropping wakeup data, as long as there is wakeup data
 297          * present in the pipe buffer to wake up the other end), the other end
 298          * should perform the following sequence for waiting:
 299          *
 300          * 1) empty the pipe (reads).
 301          * 2) perform update operation.
 302          * 3) wait on the pipe (poll).
 303          */
 304         do {
 305                 ret = write(ctx->consumer_poll_pipe[1], "", 1);
 306         } while (ret < 0 && errno == EINTR);
 307 end_nosignal:
 308         /* XXX: At some point we might want to return something else than zero */
 309         rcu_read_unlock();
 310         return 0;
 311 }
 312
 313 int lttng_ustconsumer_allocate_channel(struct lttng_consumer_channel *chan)
 314 {
 315         struct lttng_ust_object_data obj;
 316
 317         obj.handle = -1;
 318         obj.shm_fd = chan->shm_fd;
 319         obj.wait_fd = chan->wait_fd;
 320         obj.memory_map_size = chan->mmap_len;
 321         chan->handle = ustctl_map_channel(&obj);
 322         if (!chan->handle) {
 323                 return -ENOMEM;
 324         }
 325         chan->wait_fd_is_copy = 1;
 326         chan->shm_fd = -1;
 327
 328         return 0;
 329 }
 330
 331 void lttng_ustconsumer_on_stream_hangup(struct lttng_consumer_stream *stream)
 332 {
 333         ustctl_flush_buffer(stream->chan->handle, stream->buf, 0);
 334         stream->hangup_flush_done = 1;
 335 }
 336
 337 void lttng_ustconsumer_del_channel(struct lttng_consumer_channel *chan)
 338 {
 339         ustctl_unmap_channel(chan->handle);
 340 }
 341
 342 int lttng_ustconsumer_allocate_stream(struct lttng_consumer_stream *stream)
 343 {
 344         struct lttng_ust_object_data obj;
 345         int ret;
 346
 347         obj.handle = -1;
 348         obj.shm_fd = stream->shm_fd;
 349         obj.wait_fd = stream->wait_fd;
 350         obj.memory_map_size = stream->mmap_len;
 351         ret = ustctl_add_stream(stream->chan->handle, &obj);
 352         if (ret)
 353                 return ret;
 354         stream->buf = ustctl_open_stream_read(stream->chan->handle, stream->cpu);
 355         if (!stream->buf)
 356                 return -EBUSY;
 357         /* ustctl_open_stream_read has closed the shm fd. */
 358         stream->wait_fd_is_copy = 1;
 359         stream->shm_fd = -1;
 360
 361         stream->mmap_base = ustctl_get_mmap_base(stream->chan->handle, stream->buf);
 362         if (!stream->mmap_base) {
 363                 return -EINVAL;
 364         }
 365
 366         return 0;
 367 }
 368
 369 void lttng_ustconsumer_del_stream(struct lttng_consumer_stream *stream)
 370 {
 371         ustctl_close_stream_read(stream->chan->handle, stream->buf);
 372 }
 373
 374
 375 int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 376                 struct lttng_consumer_local_data *ctx)
 377 {
 378         unsigned long len;
 379         int err;
 380         long ret = 0;
 381         struct lttng_ust_shm_handle *handle;
 382         struct lttng_ust_lib_ring_buffer *buf;
 383         char dummy;
 384         ssize_t readlen;
 385
 386         DBG("In read_subbuffer (wait_fd: %d, stream key: %d)",
 387                 stream->wait_fd, stream->key);
 388
 389         /* We can consume the 1 byte written into the wait_fd by UST */
 390         if (!stream->hangup_flush_done) {
 391                 do {
 392                         readlen = read(stream->wait_fd, &dummy, 1);
 393                 } while (readlen == -1 && errno == EINTR);
 394                 if (readlen == -1) {
 395                         ret = readlen;
 396                         goto end;
 397                 }
 398         }
 399
 400         buf = stream->buf;
 401         handle = stream->chan->handle;
 402         /* Get the next subbuffer */
 403         err = ustctl_get_next_subbuf(handle, buf);
 404         if (err != 0) {
 405                 ret = -ret;     /* ustctl_get_next_subbuf returns negative, caller expect positive. */
 406                 /*
 407                  * This is a debug message even for single-threaded consumer,
 408                  * because poll() have more relaxed criterions than get subbuf,
 409                  * so get_subbuf may fail for short race windows where poll()
 410                  * would issue wakeups.
 411                  */
 412                 DBG("Reserving sub buffer failed (everything is normal, "
 413                                 "it is due to concurrency)");
 414                 goto end;
 415         }
 416         assert(stream->output == LTTNG_EVENT_MMAP);
 417         /* read the used subbuffer size */
 418         err = ustctl_get_padded_subbuf_size(handle, buf, &len);
 419         assert(err == 0);
 420         /* write the subbuffer to the tracefile */
 421         ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
 422         if (ret != len) {
 423                 /*
 424                  * display the error but continue processing to try
 425                  * to release the subbuffer
 426                  */
 427                 ERR("Error writing to tracefile (expected: %ld, got: %ld)", ret, len);
 428         }
 429         err = ustctl_put_next_subbuf(handle, buf);
 430         assert(err == 0);
 431 end:
 432         return ret;
 433 }
 434
 435 int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
 436 {
 437         int ret;
 438
 439         /* Opening the tracefile in write mode */
 440         if (stream->path_name != NULL && stream->net_seq_idx == -1) {
 441                 ret = run_as_open(stream->path_name,
 442                                 O_WRONLY|O_CREAT|O_TRUNC,
 443                                 S_IRWXU|S_IRWXG|S_IRWXO,
 444                                 stream->uid, stream->gid);
 445                 if (ret < 0) {
 446                         ERR("Opening %s", stream->path_name);
 447                         PERROR("open");
 448                         goto error;
 449                 }
 450                 stream->out_fd = ret;
 451         }
 452
 453         /* we return 0 to let the library handle the FD internally */
 454         return 0;
 455
 456 error:
 457         return ret;
 458 }