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