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