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 _GNU_SOURCE
  21 #define _LGPL_SOURCE
  22 #include <common/common.h>
  23 #include <common/index/index.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;
  47
  48         vstream = zmalloc(sizeof(*vstream));
  49         if (!vstream) {
  50                 PERROR("relay viewer stream zmalloc");
  51                 goto error;
  52         }
  53
  54         vstream->path_name = strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX);
  55         if (vstream->path_name == NULL) {
  56                 PERROR("relay viewer path_name alloc");
  57                 goto error;
  58         }
  59         vstream->channel_name = strndup(stream->channel_name,
  60                         LTTNG_VIEWER_NAME_MAX);
  61         if (vstream->channel_name == NULL) {
  62                 PERROR("relay viewer channel_name alloc");
  63                 goto error;
  64         }
  65
  66         switch (seek_t) {
  67         case LTTNG_VIEWER_SEEK_BEGINNING:
  68                 vstream->current_tracefile_id = stream->oldest_tracefile_id;
  69                 break;
  70         case LTTNG_VIEWER_SEEK_LAST:
  71                 vstream->current_tracefile_id = stream->current_tracefile_id;
  72                 break;
  73         default:
  74                 goto error;
  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 we never received an index for the current stream, delay the opening
  85          * of the index, otherwise open it right now.
  86          */
  87         if (vstream->current_tracefile_id == stream->current_tracefile_id
  88                         && stream->total_index_received == 0) {
  89                 vstream->index_fd = NULL;
  90         } else {
  91                 int read_fd;
  92
  93                 read_fd = index_open(vstream->path_name, vstream->channel_name,
  94                                 stream->tracefile_count,
  95                                 vstream->current_tracefile_id);
  96                 if (read_fd < 0) {
  97                         goto error_unlock;
  98                 }
  99                 vstream->index_fd = stream_fd_create(read_fd);
 100                 if (!vstream->index_fd) {
 101                         if (close(read_fd)) {
 102                                 PERROR("close");
 103                         }
 104                         goto error_unlock;
 105                 }
 106         }
 107
 108         if (seek_t == LTTNG_VIEWER_SEEK_LAST && vstream->index_fd) {
 109                 off_t lseek_ret;
 110
 111                 lseek_ret = lseek(vstream->index_fd->fd, 0, SEEK_END);
 112                 if (lseek_ret < 0) {
 113                         goto error_unlock;
 114                 }
 115                 vstream->last_sent_index = stream->total_index_received;
 116         }
 117         pthread_mutex_unlock(&stream->lock);
 118
 119         if (stream->is_metadata) {
 120                 rcu_assign_pointer(stream->trace->viewer_metadata_stream,
 121                                 vstream);
 122         }
 123
 124         /* Globally visible after the add unique. */
 125         lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
 126         lttng_ht_add_unique_u64(viewer_streams_ht, &vstream->stream_n);
 127
 128         pthread_mutex_init(&vstream->reflock, NULL);
 129         urcu_ref_init(&vstream->ref);
 130
 131         return vstream;
 132
 133 error_unlock:
 134         pthread_mutex_unlock(&stream->lock);
 135 error:
 136         if (vstream) {
 137                 viewer_stream_destroy(vstream);
 138         }
 139         return NULL;
 140 }
 141
 142 static void viewer_stream_unpublish(struct relay_viewer_stream *vstream)
 143 {
 144         int ret;
 145         struct lttng_ht_iter iter;
 146
 147         iter.iter.node = &vstream->stream_n.node;
 148         ret = lttng_ht_del(viewer_streams_ht, &iter);
 149         assert(!ret);
 150 }
 151
 152 static void viewer_stream_release(struct urcu_ref *ref)
 153 {
 154         struct relay_viewer_stream *vstream = caa_container_of(ref,
 155                         struct relay_viewer_stream, ref);
 156
 157         if (vstream->stream->is_metadata) {
 158                 rcu_assign_pointer(vstream->stream->trace->viewer_metadata_stream, NULL);
 159         }
 160
 161         viewer_stream_unpublish(vstream);
 162
 163         if (vstream->stream_fd) {
 164                 stream_fd_put(vstream->stream_fd);
 165                 vstream->stream_fd = NULL;
 166         }
 167         if (vstream->index_fd) {
 168                 stream_fd_put(vstream->index_fd);
 169                 vstream->index_fd = NULL;
 170         }
 171         if (vstream->stream) {
 172                 stream_put(vstream->stream);
 173                 vstream->stream = NULL;
 174         }
 175         call_rcu(&vstream->rcu_node, viewer_stream_destroy_rcu);
 176 }
 177
 178 /* Must be called with RCU read-side lock held. */
 179 bool viewer_stream_get(struct relay_viewer_stream *vstream)
 180 {
 181         bool has_ref = false;
 182
 183         pthread_mutex_lock(&vstream->reflock);
 184         if (vstream->ref.refcount != 0) {
 185                 has_ref = true;
 186                 urcu_ref_get(&vstream->ref);
 187         }
 188         pthread_mutex_unlock(&vstream->reflock);
 189
 190         return has_ref;
 191 }
 192
 193 /*
 194  * Get viewer stream by id.
 195  *
 196  * Return viewer stream if found else NULL.
 197  */
 198 struct relay_viewer_stream *viewer_stream_get_by_id(uint64_t id)
 199 {
 200         struct lttng_ht_node_u64 *node;
 201         struct lttng_ht_iter iter;
 202         struct relay_viewer_stream *vstream = NULL;
 203
 204         rcu_read_lock();
 205         lttng_ht_lookup(viewer_streams_ht, &id, &iter);
 206         node = lttng_ht_iter_get_node_u64(&iter);
 207         if (!node) {
 208                 DBG("Relay viewer stream %" PRIu64 " not found", id);
 209                 goto end;
 210         }
 211         vstream = caa_container_of(node, struct relay_viewer_stream, stream_n);
 212         if (!viewer_stream_get(vstream)) {
 213                 vstream = NULL;
 214         }
 215 end:
 216         rcu_read_unlock();
 217         return vstream;
 218 }
 219
 220 void viewer_stream_put(struct relay_viewer_stream *vstream)
 221 {
 222         rcu_read_lock();
 223         pthread_mutex_lock(&vstream->reflock);
 224         urcu_ref_put(&vstream->ref, viewer_stream_release);
 225         pthread_mutex_unlock(&vstream->reflock);
 226         rcu_read_unlock();
 227 }
 228
 229 /*
 230  * Returns whether the current tracefile is readable. If not, it has
 231  * been overwritten.
 232  * Must be called with rstream lock held.
 233  */
 234 bool viewer_stream_is_tracefile_seq_readable(struct relay_viewer_stream *vstream,
 235                  uint64_t seq)
 236 {
 237         struct relay_stream *stream = vstream->stream;
 238
 239         if (seq >= stream->oldest_tracefile_seq
 240                         && seq <= stream->current_tracefile_seq) {
 241                 /* seq is a readable file. */
 242                 return true;
 243         } else {
 244                 /* seq is not readable. */
 245                 return false;
 246         }
 247 }
 248
 249 /*
 250  * Rotate a stream to the next tracefile.
 251  *
 252  * Must be called with the rstream lock held.
 253  * Returns 0 on success, 1 on EOF, a negative value on error.
 254  */
 255 int viewer_stream_rotate(struct relay_viewer_stream *vstream)
 256 {
 257         int ret;
 258         struct relay_stream *stream = vstream->stream;
 259
 260         /* Detect the last tracefile to open. */
 261         if (stream->total_index_received == vstream->last_sent_index
 262                         && stream->trace->session->connection_closed) {
 263                 ret = 1;
 264                 goto end;
 265         }
 266
 267         if (stream->tracefile_count == 0) {
 268                 /* Ignore rotation, there is none to do. */
 269                 ret = 0;
 270                 goto end;
 271         }
 272
 273         if (!viewer_stream_is_tracefile_seq_readable(vstream,
 274                         vstream->current_tracefile_seq + 1)) {
 275                 vstream->current_tracefile_id =
 276                                 stream->oldest_tracefile_id;
 277                 vstream->current_tracefile_seq =
 278                                 stream->oldest_tracefile_seq;
 279         } else {
 280                 vstream->current_tracefile_id =
 281                                 (vstream->current_tracefile_id + 1)
 282                                         % stream->tracefile_count;
 283                 vstream->current_tracefile_seq++;
 284         }
 285
 286         if (vstream->index_fd) {
 287                 stream_fd_put(vstream->index_fd);
 288                 vstream->index_fd = NULL;
 289         }
 290         if (vstream->stream_fd) {
 291                 stream_fd_put(vstream->stream_fd);
 292                 vstream->stream_fd = NULL;
 293         }
 294
 295         ret = index_open(vstream->path_name, vstream->channel_name,
 296                         stream->tracefile_count,
 297                         vstream->current_tracefile_id);
 298         if (ret < 0) {
 299                 goto end;
 300         }
 301         vstream->index_fd = stream_fd_create(ret);
 302         if (vstream->index_fd) {
 303                 ret = 0;
 304         } else {
 305                 if (close(ret)) {
 306                         PERROR("close");
 307                 }
 308                 ret = -1;
 309         }
 310 end:
 311         return ret;
 312 }
 313
 314 void print_viewer_streams(void)
 315 {
 316         struct lttng_ht_iter iter;
 317         struct relay_viewer_stream *vstream;
 318
 319         rcu_read_lock();
 320         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
 321                         stream_n.node) {
 322                 if (!viewer_stream_get(vstream)) {
 323                         continue;
 324                 }
 325                 DBG("vstream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
 326                         " session %" PRIu64,
 327                         vstream,
 328                         vstream->ref.refcount,
 329                         vstream->stream->stream_handle,
 330                         vstream->stream->trace->id,
 331                         vstream->stream->trace->session->id);
 332                 viewer_stream_put(vstream);
 333         }
 334         rcu_read_unlock();
 335 }