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         free(vstream->path_name);
  31         free(vstream->channel_name);
  32         free(vstream);
  33 }
  34
  35 static void viewer_stream_destroy_rcu(struct rcu_head *head)
  36 {
  37         struct relay_viewer_stream *vstream =
  38                 caa_container_of(head, struct relay_viewer_stream, rcu_node);
  39
  40         viewer_stream_destroy(vstream);
  41 }
  42
  43 struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
  44                 struct lttng_trace_chunk *viewer_trace_chunk,
  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                         viewer_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 = viewer_trace_chunk;
  62         viewer_trace_chunk = NULL;
  63         vstream->path_name = lttng_strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX);
  64         if (vstream->path_name == NULL) {
  65                 PERROR("relay viewer path_name alloc");
  66                 goto error;
  67         }
  68         vstream->channel_name = lttng_strndup(stream->channel_name,
  69                         LTTNG_VIEWER_NAME_MAX);
  70         if (vstream->channel_name == NULL) {
  71                 PERROR("relay viewer channel_name alloc");
  72                 goto error;
  73         }
  74
  75         if (!stream_get(stream)) {
  76                 ERR("Cannot get stream");
  77                 goto error;
  78         }
  79         vstream->stream = stream;
  80
  81         pthread_mutex_lock(&stream->lock);
  82
  83         if (stream->is_metadata && stream->trace->viewer_metadata_stream) {
  84                 ERR("Cannot attach viewer metadata stream to trace (busy).");
  85                 goto error_unlock;
  86         }
  87
  88         switch (seek_t) {
  89         case LTTNG_VIEWER_SEEK_BEGINNING:
  90         {
  91                 uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
  92
  93                 if (seq_tail == -1ULL) {
  94                         /*
  95                          * Tail may not be initialized yet. Nonetheless, we know
  96                          * we want to send the first index once it becomes
  97                          * available.
  98                          */
  99                         seq_tail = 0;
 100                 }
 101                 vstream->current_tracefile_id =
 102                         tracefile_array_get_file_index_tail(stream->tfa);
 103                 vstream->index_sent_seqcount = seq_tail;
 104                 break;
 105         }
 106         case LTTNG_VIEWER_SEEK_LAST:
 107                 vstream->current_tracefile_id =
 108                         tracefile_array_get_read_file_index_head(stream->tfa);
 109                 /*
 110                  * We seek at the very end of each stream, awaiting for
 111                  * a future packet to eventually come in.
 112                  *
 113                  * We don't need to check the head position for -1ULL since the
 114                  * increment will set it to 0.
 115                  */
 116                 vstream->index_sent_seqcount =
 117                                 tracefile_array_get_seq_head(stream->tfa) + 1;
 118                 break;
 119         default:
 120                 goto error_unlock;
 121         }
 122
 123         /*
 124          * If we never received an index for the current stream, delay
 125          * the opening of the index, otherwise open it right now.
 126          */
 127         if (stream->index_received_seqcount == 0) {
 128                 vstream->index_file = NULL;
 129         } else {
 130                 const uint32_t connection_major = stream->trace->session->major;
 131                 const uint32_t connection_minor = stream->trace->session->minor;
 132
 133                 vstream->index_file = lttng_index_file_create_from_trace_chunk_read_only(
 134                                 vstream->stream_file.trace_chunk,
 135                                 stream->path_name,
 136                                 stream->channel_name, stream->tracefile_size,
 137                                 vstream->current_tracefile_id,
 138                                 lttng_to_index_major(connection_major,
 139                                                 connection_minor),
 140                                 lttng_to_index_minor(connection_major,
 141                                                 connection_minor));
 142                 if (!vstream->index_file) {
 143                         goto error_unlock;
 144                 }
 145         }
 146
 147         if (seek_t == LTTNG_VIEWER_SEEK_LAST && vstream->index_file) {
 148                 off_t lseek_ret;
 149
 150                 lseek_ret = lseek(vstream->index_file->fd, 0, SEEK_END);
 151                 if (lseek_ret < 0) {
 152                         goto error_unlock;
 153                 }
 154         }
 155         if (stream->is_metadata) {
 156                 rcu_assign_pointer(stream->trace->viewer_metadata_stream,
 157                                 vstream);
 158         }
 159         pthread_mutex_unlock(&stream->lock);
 160
 161         /* Globally visible after the add unique. */
 162         lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
 163         lttng_ht_add_unique_u64(viewer_streams_ht, &vstream->stream_n);
 164
 165         urcu_ref_init(&vstream->ref);
 166
 167         return vstream;
 168
 169 error_unlock:
 170         pthread_mutex_unlock(&stream->lock);
 171 error:
 172         if (vstream) {
 173                 viewer_stream_destroy(vstream);
 174         }
 175         if (viewer_trace_chunk && acquired_reference) {
 176                 lttng_trace_chunk_put(viewer_trace_chunk);
 177         }
 178         return NULL;
 179 }
 180
 181 static void viewer_stream_unpublish(struct relay_viewer_stream *vstream)
 182 {
 183         int ret;
 184         struct lttng_ht_iter iter;
 185
 186         iter.iter.node = &vstream->stream_n.node;
 187         ret = lttng_ht_del(viewer_streams_ht, &iter);
 188         assert(!ret);
 189 }
 190
 191 static void viewer_stream_release(struct urcu_ref *ref)
 192 {
 193         struct relay_viewer_stream *vstream = caa_container_of(ref,
 194                         struct relay_viewer_stream, ref);
 195
 196         if (vstream->stream->is_metadata) {
 197                 rcu_assign_pointer(vstream->stream->trace->viewer_metadata_stream, NULL);
 198         }
 199
 200         viewer_stream_unpublish(vstream);
 201
 202         if (vstream->stream_file.fd) {
 203                 stream_fd_put(vstream->stream_file.fd);
 204                 vstream->stream_file.fd = NULL;
 205         }
 206         if (vstream->index_file) {
 207                 lttng_index_file_put(vstream->index_file);
 208                 vstream->index_file = NULL;
 209         }
 210         if (vstream->stream) {
 211                 stream_put(vstream->stream);
 212                 vstream->stream = NULL;
 213         }
 214         lttng_trace_chunk_put(vstream->stream_file.trace_chunk);
 215         vstream->stream_file.trace_chunk = NULL;
 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 }