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