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