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