src/bin/lttng-relayd/viewer-stream.c

   1 /*
   2  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   3  *                      David Goulet <dgoulet@efficios.com>
   4  *               2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License, version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc., 51
  17  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #define _LGPL_SOURCE
  21 #include <common/common.h>
  22 #include <common/index/index.h>
  23 #include <common/compat/string.h>
  24 #include <common/utils.h>
  25 #include <sys/types.h>
  26 #include <sys/stat.h>
  27 #include <fcntl.h>
  28
  29 #include "lttng-relayd.h"
  30 #include "viewer-stream.h"
  31
  32 static void viewer_stream_destroy(struct relay_viewer_stream *vstream)
  33 {
  34         free(vstream->path_name);
  35         free(vstream->channel_name);
  36         free(vstream);
  37 }
  38
  39 static void viewer_stream_destroy_rcu(struct rcu_head *head)
  40 {
  41         struct relay_viewer_stream *vstream =
  42                 caa_container_of(head, struct relay_viewer_stream, rcu_node);
  43
  44         viewer_stream_destroy(vstream);
  45 }
  46
  47 struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
  48                 struct lttng_trace_chunk *viewer_trace_chunk,
  49                 enum lttng_viewer_seek seek_t)
  50 {
  51         struct relay_viewer_stream *vstream = NULL;
  52         const bool acquired_reference = lttng_trace_chunk_get(
  53                         viewer_trace_chunk);
  54
  55         if (!acquired_reference) {
  56                 goto error;
  57         }
  58
  59         vstream = zmalloc(sizeof(*vstream));
  60         if (!vstream) {
  61                 PERROR("relay viewer stream zmalloc");
  62                 goto error;
  63         }
  64
  65         vstream->stream_file.trace_chunk = viewer_trace_chunk;
  66         viewer_trace_chunk = NULL;
  67         vstream->path_name = lttng_strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX);
  68         if (vstream->path_name == NULL) {
  69                 PERROR("relay viewer path_name alloc");
  70                 goto error;
  71         }
  72         vstream->channel_name = lttng_strndup(stream->channel_name,
  73                         LTTNG_VIEWER_NAME_MAX);
  74         if (vstream->channel_name == NULL) {
  75                 PERROR("relay viewer channel_name alloc");
  76                 goto error;
  77         }
  78
  79         if (!stream_get(stream)) {
  80                 ERR("Cannot get stream");
  81                 goto error;
  82         }
  83         vstream->stream = stream;
  84
  85         pthread_mutex_lock(&stream->lock);
  86
  87         if (stream->is_metadata && stream->trace->viewer_metadata_stream) {
  88                 ERR("Cannot attach viewer metadata stream to trace (busy).");
  89                 goto error_unlock;
  90         }
  91
  92         switch (seek_t) {
  93         case LTTNG_VIEWER_SEEK_BEGINNING:
  94         {
  95                 uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
  96
  97                 if (seq_tail == -1ULL) {
  98                         /*
  99                          * Tail may not be initialized yet. Nonetheless, we know
 100                          * we want to send the first index once it becomes
 101                          * available.
 102                          */
 103                         seq_tail = 0;
 104                 }
 105                 vstream->current_tracefile_id =
 106                         tracefile_array_get_file_index_tail(stream->tfa);
 107                 vstream->index_sent_seqcount = seq_tail;
 108                 break;
 109         }
 110         case LTTNG_VIEWER_SEEK_LAST:
 111                 vstream->current_tracefile_id =
 112                         tracefile_array_get_read_file_index_head(stream->tfa);
 113                 /*
 114                  * We seek at the very end of each stream, awaiting for
 115                  * a future packet to eventually come in.
 116                  *
 117                  * We don't need to check the head position for -1ULL since the
 118                  * increment will set it to 0.
 119                  */
 120                 vstream->index_sent_seqcount =
 121                                 tracefile_array_get_seq_head(stream->tfa) + 1;
 122                 break;
 123         default:
 124                 goto error_unlock;
 125         }
 126
 127         /*
 128          * If we never received an index for the current stream, delay
 129          * the opening of the index, otherwise open it right now.
 130          */
 131         if (stream->index_file == NULL) {
 132                 vstream->index_file = NULL;
 133         } else {
 134                 const uint32_t connection_major = stream->trace->session->major;
 135                 const uint32_t connection_minor = stream->trace->session->minor;
 136                 enum lttng_trace_chunk_status chunk_status;
 137
 138                 chunk_status = lttng_index_file_create_from_trace_chunk_read_only(
 139                                 vstream->stream_file.trace_chunk,
 140                                 stream->path_name,
 141                                 stream->channel_name, stream->tracefile_size,
 142                                 vstream->current_tracefile_id,
 143                                 lttng_to_index_major(connection_major,
 144                                                 connection_minor),
 145                                 lttng_to_index_minor(connection_major,
 146                                                 connection_minor),
 147                                 true, &vstream->index_file);
 148                 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
 149                         if (chunk_status == LTTNG_TRACE_CHUNK_STATUS_NO_FILE) {
 150                                 vstream->index_file = NULL;
 151                         } else {
 152                                 goto error_unlock;
 153                         }
 154                 }
 155         }
 156
 157         /*
 158          * If we never received a data file for the current stream, delay the
 159          * opening, otherwise open it right now.
 160          */
 161         if (stream->stream_fd) {
 162                 int fd, ret;
 163                 char file_path[LTTNG_PATH_MAX];
 164                 enum lttng_trace_chunk_status status;
 165
 166                 ret = utils_stream_file_path(stream->path_name,
 167                                 stream->channel_name, stream->tracefile_size,
 168                                 vstream->current_tracefile_id, NULL, file_path,
 169                                 sizeof(file_path));
 170                 if (ret < 0) {
 171                         goto error_unlock;
 172                 }
 173
 174                 status = lttng_trace_chunk_open_file(
 175                                 vstream->stream_file.trace_chunk,
 176                                 file_path, O_RDONLY, 0, &fd, true);
 177                 if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
 178                         goto error_unlock;
 179                 }
 180                 vstream->stream_file.fd = stream_fd_create(fd);
 181                 if (!vstream->stream_file.fd) {
 182                         if (close(fd)) {
 183                                 PERROR("Failed to close viewer %sfile",
 184                                         stream->is_metadata ? "metadata " : "");
 185                         }
 186                         goto error_unlock;
 187                 }
 188         }
 189
 190         if (seek_t == LTTNG_VIEWER_SEEK_LAST && vstream->index_file) {
 191                 off_t lseek_ret;
 192
 193                 lseek_ret = lseek(vstream->index_file->fd, 0, SEEK_END);
 194                 if (lseek_ret < 0) {
 195                         goto error_unlock;
 196                 }
 197         }
 198         if (stream->is_metadata) {
 199                 rcu_assign_pointer(stream->trace->viewer_metadata_stream,
 200                                 vstream);
 201         }
 202         pthread_mutex_unlock(&stream->lock);
 203
 204         /* Globally visible after the add unique. */
 205         lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
 206         urcu_ref_init(&vstream->ref);
 207         lttng_ht_add_unique_u64(viewer_streams_ht, &vstream->stream_n);
 208
 209         return vstream;
 210
 211 error_unlock:
 212         pthread_mutex_unlock(&stream->lock);
 213 error:
 214         if (vstream) {
 215                 viewer_stream_destroy(vstream);
 216         }
 217         if (viewer_trace_chunk && acquired_reference) {
 218                 lttng_trace_chunk_put(viewer_trace_chunk);
 219         }
 220         return NULL;
 221 }
 222
 223 static void viewer_stream_unpublish(struct relay_viewer_stream *vstream)
 224 {
 225         int ret;
 226         struct lttng_ht_iter iter;
 227
 228         iter.iter.node = &vstream->stream_n.node;
 229         ret = lttng_ht_del(viewer_streams_ht, &iter);
 230         assert(!ret);
 231 }
 232
 233 static void viewer_stream_release(struct urcu_ref *ref)
 234 {
 235         struct relay_viewer_stream *vstream = caa_container_of(ref,
 236                         struct relay_viewer_stream, ref);
 237
 238         if (vstream->stream->is_metadata) {
 239                 rcu_assign_pointer(vstream->stream->trace->viewer_metadata_stream, NULL);
 240         }
 241
 242         viewer_stream_unpublish(vstream);
 243
 244         if (vstream->stream_file.fd) {
 245                 stream_fd_put(vstream->stream_file.fd);
 246                 vstream->stream_file.fd = NULL;
 247         }
 248         if (vstream->index_file) {
 249                 lttng_index_file_put(vstream->index_file);
 250                 vstream->index_file = NULL;
 251         }
 252         if (vstream->stream) {
 253                 stream_put(vstream->stream);
 254                 vstream->stream = NULL;
 255         }
 256         lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
 257         vstream->stream_file.trace_chunk = NULL;
 258         call_rcu(&vstream->rcu_node, viewer_stream_destroy_rcu);
 259 }
 260
 261 /* Must be called with RCU read-side lock held. */
 262 bool viewer_stream_get(struct relay_viewer_stream *vstream)
 263 {
 264         return urcu_ref_get_unless_zero(&vstream->ref);
 265 }
 266
 267 /*
 268  * Get viewer stream by id.
 269  *
 270  * Return viewer stream if found else NULL.
 271  */
 272 struct relay_viewer_stream *viewer_stream_get_by_id(uint64_t id)
 273 {
 274         struct lttng_ht_node_u64 *node;
 275         struct lttng_ht_iter iter;
 276         struct relay_viewer_stream *vstream = NULL;
 277
 278         rcu_read_lock();
 279         lttng_ht_lookup(viewer_streams_ht, &id, &iter);
 280         node = lttng_ht_iter_get_node_u64(&iter);
 281         if (!node) {
 282                 DBG("Relay viewer stream %" PRIu64 " not found", id);
 283                 goto end;
 284         }
 285         vstream = caa_container_of(node, struct relay_viewer_stream, stream_n);
 286         if (!viewer_stream_get(vstream)) {
 287                 vstream = NULL;
 288         }
 289 end:
 290         rcu_read_unlock();
 291         return vstream;
 292 }
 293
 294 void viewer_stream_put(struct relay_viewer_stream *vstream)
 295 {
 296         rcu_read_lock();
 297         urcu_ref_put(&vstream->ref, viewer_stream_release);
 298         rcu_read_unlock();
 299 }
 300
 301 void viewer_stream_close_files(struct relay_viewer_stream *vstream)
 302 {
 303         if (vstream->index_file) {
 304                 lttng_index_file_put(vstream->index_file);
 305                 vstream->index_file = NULL;
 306         }
 307         if (vstream->stream_file.fd) {
 308                 stream_fd_put(vstream->stream_file.fd);
 309                 vstream->stream_file.fd = NULL;
 310         }
 311 }
 312
 313 void viewer_stream_sync_tracefile_array_tail(struct relay_viewer_stream *vstream)
 314 {
 315         const struct relay_stream *stream = vstream->stream;
 316         uint64_t seq_tail;
 317
 318         vstream->current_tracefile_id = tracefile_array_get_file_index_tail(stream->tfa);
 319         seq_tail = tracefile_array_get_seq_tail(stream->tfa);
 320         if (seq_tail == -1ULL) {
 321                 seq_tail = 0;
 322         }
 323         vstream->index_sent_seqcount = seq_tail;
 324 }
 325
 326 /*
 327  * Rotate a stream to the next tracefile.
 328  *
 329  * Must be called with the rstream lock held.
 330  * Returns 0 on success, 1 on EOF.
 331  */
 332 int viewer_stream_rotate(struct relay_viewer_stream *vstream)
 333 {
 334         int ret;
 335         uint64_t new_id;
 336         const struct relay_stream *stream = vstream->stream;
 337
 338         /* Detect the last tracefile to open. */
 339         if (stream->index_received_seqcount
 340                         == vstream->index_sent_seqcount
 341                         && stream->trace->session->connection_closed) {
 342                 ret = 1;
 343                 goto end;
 344         }
 345
 346         if (stream->tracefile_count == 0) {
 347                 /* Ignore rotation, there is none to do. */
 348                 ret = 0;
 349                 goto end;
 350         }
 351
 352         /*
 353          * Try to move to the next file.
 354          */
 355         new_id = (vstream->current_tracefile_id + 1)
 356                         % stream->tracefile_count;
 357         if (tracefile_array_seq_in_file(stream->tfa, new_id,
 358                         vstream->index_sent_seqcount)) {
 359                 vstream->current_tracefile_id = new_id;
 360         } else {
 361                 uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
 362
 363                 /*
 364                  * This can only be reached on overwrite, which implies there
 365                  * has been data written at some point, which will have set the
 366                  * tail.
 367                  */
 368                 assert(seq_tail != -1ULL);
 369                 /*
 370                  * We need to resync because we lag behind tail.
 371                  */
 372                 vstream->current_tracefile_id =
 373                         tracefile_array_get_file_index_tail(stream->tfa);
 374                 vstream->index_sent_seqcount = seq_tail;
 375         }
 376         viewer_stream_close_files(vstream);
 377         ret = 0;
 378 end:
 379         return ret;
 380 }
 381
 382 void print_viewer_streams(void)
 383 {
 384         struct lttng_ht_iter iter;
 385         struct relay_viewer_stream *vstream;
 386
 387         if (!viewer_streams_ht) {
 388                 return;
 389         }
 390
 391         rcu_read_lock();
 392         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
 393                         stream_n.node) {
 394                 if (!viewer_stream_get(vstream)) {
 395                         continue;
 396                 }
 397                 DBG("vstream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
 398                         " session %" PRIu64,
 399                         vstream,
 400                         vstream->ref.refcount,
 401                         vstream->stream->stream_handle,
 402                         vstream->stream->trace->id,
 403                         vstream->stream->trace->session->id);
 404                 viewer_stream_put(vstream);
 405         }
 406         rcu_read_unlock();
 407 }