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

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