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

   1 /*
   2  * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com>
   3  * Copyright (C) 2013 David Goulet <dgoulet@efficios.com>
   4  * Copyright (C) 2015 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * SPDX-License-Identifier: GPL-2.0-only
   7  *
   8  */
   9
  10 #define _LGPL_SOURCE
  11 #include <common/common.h>
  12 #include <common/index/index.h>
  13 #include <common/compat/string.h>
  14 #include <common/utils.h>
  15 #include <sys/types.h>
  16 #include <sys/stat.h>
  17 #include <fcntl.h>
  18 #include <algorithm>
  19
  20 #include "lttng-relayd.h"
  21 #include "viewer-stream.h"
  22
  23 static void viewer_stream_destroy(struct relay_viewer_stream *vstream)
  24 {
  25         lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
  26         free(vstream->path_name);
  27         free(vstream->channel_name);
  28         free(vstream);
  29 }
  30
  31 static void viewer_stream_destroy_rcu(struct rcu_head *head)
  32 {
  33         struct relay_viewer_stream *vstream =
  34                 caa_container_of(head, struct relay_viewer_stream, rcu_node);
  35
  36         viewer_stream_destroy(vstream);
  37 }
  38
  39 /* Relay stream's lock must be held by the caller. */
  40 struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
  41                 struct lttng_trace_chunk *trace_chunk,
  42                 enum lttng_viewer_seek seek_t)
  43 {
  44         struct relay_viewer_stream *vstream = NULL;
  45
  46         ASSERT_LOCKED(stream->lock);
  47
  48         vstream = (relay_viewer_stream *) zmalloc(sizeof(*vstream));
  49         if (!vstream) {
  50                 PERROR("relay viewer stream zmalloc");
  51                 goto error;
  52         }
  53
  54         if (trace_chunk) {
  55                 const bool acquired_reference = lttng_trace_chunk_get(
  56                                 trace_chunk);
  57
  58                 LTTNG_ASSERT(acquired_reference);
  59         }
  60
  61         vstream->stream_file.trace_chunk = trace_chunk;
  62         vstream->path_name = lttng_strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX);
  63         if (vstream->path_name == NULL) {
  64                 PERROR("relay viewer path_name alloc");
  65                 goto error;
  66         }
  67         vstream->channel_name = lttng_strndup(stream->channel_name,
  68                         LTTNG_VIEWER_NAME_MAX);
  69         if (vstream->channel_name == NULL) {
  70                 PERROR("relay viewer channel_name alloc");
  71                 goto error;
  72         }
  73
  74         if (!stream_get(stream)) {
  75                 ERR("Cannot get stream");
  76                 goto error;
  77         }
  78         vstream->stream = stream;
  79
  80         if (stream->is_metadata && stream->trace->viewer_metadata_stream) {
  81                 ERR("Cannot attach viewer metadata stream to trace (busy).");
  82                 goto error;
  83         }
  84
  85         switch (seek_t) {
  86         case LTTNG_VIEWER_SEEK_BEGINNING:
  87         {
  88                 uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
  89
  90                 if (seq_tail == -1ULL) {
  91                         /*
  92                          * Tail may not be initialized yet. Nonetheless, we know
  93                          * we want to send the first index once it becomes
  94                          * available.
  95                          */
  96                         seq_tail = 0;
  97                 }
  98                 vstream->current_tracefile_id =
  99                         tracefile_array_get_file_index_tail(stream->tfa);
 100                 vstream->index_sent_seqcount = seq_tail;
 101                 break;
 102         }
 103         case LTTNG_VIEWER_SEEK_LAST:
 104                 vstream->current_tracefile_id =
 105                         tracefile_array_get_read_file_index_head(stream->tfa);
 106                 /*
 107                  * We seek at the very end of each stream, awaiting for
 108                  * a future packet to eventually come in.
 109                  *
 110                  * We don't need to check the head position for -1ULL since the
 111                  * increment will set it to 0.
 112                  */
 113                 vstream->index_sent_seqcount =
 114                                 tracefile_array_get_seq_head(stream->tfa) + 1;
 115                 break;
 116         default:
 117                 goto error;
 118         }
 119
 120         /*
 121          * If we never received an index for the current stream, delay
 122          * the opening of the index, otherwise open it right now.
 123          */
 124         if (stream->index_file == NULL) {
 125                 vstream->index_file = NULL;
 126         } else if (vstream->stream_file.trace_chunk) {
 127                 const uint32_t connection_major = stream->trace->session->major;
 128                 const uint32_t connection_minor = stream->trace->session->minor;
 129                 enum lttng_trace_chunk_status chunk_status;
 130
 131                 chunk_status = lttng_index_file_create_from_trace_chunk_read_only(
 132                                 vstream->stream_file.trace_chunk,
 133                                 stream->path_name,
 134                                 stream->channel_name, stream->tracefile_size,
 135                                 vstream->current_tracefile_id,
 136                                 lttng_to_index_major(connection_major,
 137                                                 connection_minor),
 138                                 lttng_to_index_minor(connection_major,
 139                                                 connection_minor),
 140                                 true, &vstream->index_file);
 141                 if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
 142                         if (chunk_status == LTTNG_TRACE_CHUNK_STATUS_NO_FILE) {
 143                                 vstream->index_file = NULL;
 144                         } else {
 145                                 goto error;
 146                         }
 147                 }
 148         }
 149
 150         /*
 151          * If we never received a data file for the current stream, delay the
 152          * opening, otherwise open it right now.
 153          */
 154         if (stream->file && vstream->stream_file.trace_chunk) {
 155                 int ret;
 156                 char file_path[LTTNG_PATH_MAX];
 157                 enum lttng_trace_chunk_status status;
 158
 159                 ret = utils_stream_file_path(stream->path_name,
 160                                 stream->channel_name, stream->tracefile_size,
 161                                 vstream->current_tracefile_id, NULL, file_path,
 162                                 sizeof(file_path));
 163                 if (ret < 0) {
 164                         goto error;
 165                 }
 166
 167                 status = lttng_trace_chunk_open_fs_handle(
 168                                 vstream->stream_file.trace_chunk, file_path,
 169                                 O_RDONLY, 0, &vstream->stream_file.handle,
 170                                 true);
 171                 if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
 172                         goto error;
 173                 }
 174         }
 175
 176         if (seek_t == LTTNG_VIEWER_SEEK_LAST && vstream->index_file) {
 177                 off_t lseek_ret;
 178
 179                 lseek_ret = fs_handle_seek(
 180                                 vstream->index_file->file, 0, SEEK_END);
 181                 if (lseek_ret < 0) {
 182                         goto error;
 183                 }
 184         }
 185         if (stream->is_metadata) {
 186                 rcu_assign_pointer(stream->trace->viewer_metadata_stream,
 187                                 vstream);
 188         }
 189
 190         vstream->last_seen_rotation_count = stream->completed_rotation_count;
 191
 192         /* Globally visible after the add unique. */
 193         lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
 194         urcu_ref_init(&vstream->ref);
 195         lttng_ht_add_unique_u64(viewer_streams_ht, &vstream->stream_n);
 196
 197         return vstream;
 198
 199 error:
 200         if (vstream) {
 201                 viewer_stream_destroy(vstream);
 202         }
 203         return NULL;
 204 }
 205
 206 static void viewer_stream_unpublish(struct relay_viewer_stream *vstream)
 207 {
 208         int ret;
 209         struct lttng_ht_iter iter;
 210
 211         iter.iter.node = &vstream->stream_n.node;
 212         ret = lttng_ht_del(viewer_streams_ht, &iter);
 213         LTTNG_ASSERT(!ret);
 214 }
 215
 216 static void viewer_stream_release(struct urcu_ref *ref)
 217 {
 218         struct relay_viewer_stream *vstream = caa_container_of(ref,
 219                         struct relay_viewer_stream, ref);
 220
 221         if (vstream->stream->is_metadata) {
 222                 rcu_assign_pointer(vstream->stream->trace->viewer_metadata_stream, NULL);
 223         }
 224
 225         viewer_stream_unpublish(vstream);
 226
 227         if (vstream->stream_file.handle) {
 228                 fs_handle_close(vstream->stream_file.handle);
 229                 vstream->stream_file.handle = NULL;
 230         }
 231         if (vstream->index_file) {
 232                 lttng_index_file_put(vstream->index_file);
 233                 vstream->index_file = NULL;
 234         }
 235         if (vstream->stream) {
 236                 stream_put(vstream->stream);
 237                 vstream->stream = NULL;
 238         }
 239         lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
 240         vstream->stream_file.trace_chunk = NULL;
 241         call_rcu(&vstream->rcu_node, viewer_stream_destroy_rcu);
 242 }
 243
 244 /* Must be called with RCU read-side lock held. */
 245 bool viewer_stream_get(struct relay_viewer_stream *vstream)
 246 {
 247         return urcu_ref_get_unless_zero(&vstream->ref);
 248 }
 249
 250 /*
 251  * Get viewer stream by id.
 252  *
 253  * Return viewer stream if found else NULL.
 254  */
 255 struct relay_viewer_stream *viewer_stream_get_by_id(uint64_t id)
 256 {
 257         struct lttng_ht_node_u64 *node;
 258         struct lttng_ht_iter iter;
 259         struct relay_viewer_stream *vstream = NULL;
 260
 261         rcu_read_lock();
 262         lttng_ht_lookup(viewer_streams_ht, &id, &iter);
 263         node = lttng_ht_iter_get_node_u64(&iter);
 264         if (!node) {
 265                 DBG("Relay viewer stream %" PRIu64 " not found", id);
 266                 goto end;
 267         }
 268         vstream = caa_container_of(node, struct relay_viewer_stream, stream_n);
 269         if (!viewer_stream_get(vstream)) {
 270                 vstream = NULL;
 271         }
 272 end:
 273         rcu_read_unlock();
 274         return vstream;
 275 }
 276
 277 void viewer_stream_put(struct relay_viewer_stream *vstream)
 278 {
 279         rcu_read_lock();
 280         urcu_ref_put(&vstream->ref, viewer_stream_release);
 281         rcu_read_unlock();
 282 }
 283
 284 void viewer_stream_close_files(struct relay_viewer_stream *vstream)
 285 {
 286         if (vstream->index_file) {
 287                 lttng_index_file_put(vstream->index_file);
 288                 vstream->index_file = NULL;
 289         }
 290         if (vstream->stream_file.handle) {
 291                 fs_handle_close(vstream->stream_file.handle);
 292                 vstream->stream_file.handle = NULL;
 293         }
 294 }
 295
 296 void viewer_stream_sync_tracefile_array_tail(struct relay_viewer_stream *vstream)
 297 {
 298         const struct relay_stream *stream = vstream->stream;
 299         uint64_t seq_tail;
 300
 301         vstream->current_tracefile_id = tracefile_array_get_file_index_tail(stream->tfa);
 302         seq_tail = tracefile_array_get_seq_tail(stream->tfa);
 303         if (seq_tail == -1ULL) {
 304                 seq_tail = 0;
 305         }
 306
 307         /*
 308          * Move the index sent seqcount forward if it was lagging behind
 309          * the new tail of the tracefile array. If the current
 310          * index_sent_seqcount is already further than the tracefile
 311          * array tail position, keep its current position.
 312          */
 313         vstream->index_sent_seqcount =
 314                         std::max(seq_tail, vstream->index_sent_seqcount);
 315 }
 316
 317 /*
 318  * Rotate a stream to the next tracefile.
 319  *
 320  * Must be called with the rstream lock held.
 321  * Returns 0 on success, 1 on EOF.
 322  */
 323 int viewer_stream_rotate(struct relay_viewer_stream *vstream)
 324 {
 325         int ret;
 326         uint64_t new_id;
 327         const struct relay_stream *stream = vstream->stream;
 328
 329         /* Detect the last tracefile to open. */
 330         if (stream->index_received_seqcount
 331                         == vstream->index_sent_seqcount
 332                         && stream->trace->session->connection_closed) {
 333                 ret = 1;
 334                 goto end;
 335         }
 336
 337         if (stream->tracefile_count == 0) {
 338                 /* Ignore rotation, there is none to do. */
 339                 ret = 0;
 340                 goto end;
 341         }
 342
 343         /*
 344          * Try to move to the next file.
 345          */
 346         new_id = (vstream->current_tracefile_id + 1)
 347                         % stream->tracefile_count;
 348         if (tracefile_array_seq_in_file(stream->tfa, new_id,
 349                         vstream->index_sent_seqcount)) {
 350                 vstream->current_tracefile_id = new_id;
 351         } else {
 352                 uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
 353
 354                 /*
 355                  * This can only be reached on overwrite, which implies there
 356                  * has been data written at some point, which will have set the
 357                  * tail.
 358                  */
 359                 LTTNG_ASSERT(seq_tail != -1ULL);
 360                 /*
 361                  * We need to resync because we lag behind tail.
 362                  */
 363                 vstream->current_tracefile_id =
 364                         tracefile_array_get_file_index_tail(stream->tfa);
 365                 vstream->index_sent_seqcount = seq_tail;
 366         }
 367         viewer_stream_close_files(vstream);
 368         ret = 0;
 369 end:
 370         return ret;
 371 }
 372
 373 void print_viewer_streams(void)
 374 {
 375         struct lttng_ht_iter iter;
 376         struct relay_viewer_stream *vstream;
 377
 378         if (!viewer_streams_ht) {
 379                 return;
 380         }
 381
 382         rcu_read_lock();
 383         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
 384                         stream_n.node) {
 385                 if (!viewer_stream_get(vstream)) {
 386                         continue;
 387                 }
 388                 DBG("vstream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
 389                         " session %" PRIu64,
 390                         vstream,
 391                         vstream->ref.refcount,
 392                         vstream->stream->stream_handle,
 393                         vstream->stream->trace->id,
 394                         vstream->stream->trace->session->id);
 395                 viewer_stream_put(vstream);
 396         }
 397         rcu_read_unlock();
 398 }