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