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 #include <common/common.h>
  22 #include <common/index/index.h>
  23
  24 #include "lttng-relayd.h"
  25 #include "viewer-stream.h"
  26
  27 static void viewer_stream_destroy(struct relay_viewer_stream *vstream)
  28 {
  29         free(vstream->path_name);
  30         free(vstream->channel_name);
  31         free(vstream);
  32 }
  33
  34 static void viewer_stream_destroy_rcu(struct rcu_head *head)
  35 {
  36         struct relay_viewer_stream *vstream =
  37                 caa_container_of(head, struct relay_viewer_stream, rcu_node);
  38
  39         viewer_stream_destroy(vstream);
  40 }
  41
  42 struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
  43                 enum lttng_viewer_seek seek_t)
  44 {
  45         struct relay_viewer_stream *vstream;
  46
  47         vstream = zmalloc(sizeof(*vstream));
  48         if (!vstream) {
  49                 PERROR("relay viewer stream zmalloc");
  50                 goto error;
  51         }
  52
  53         vstream->path_name = strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX);
  54         if (vstream->path_name == NULL) {
  55                 PERROR("relay viewer path_name alloc");
  56                 goto error;
  57         }
  58         vstream->channel_name = strndup(stream->channel_name,
  59                         LTTNG_VIEWER_NAME_MAX);
  60         if (vstream->channel_name == NULL) {
  61                 PERROR("relay viewer channel_name alloc");
  62                 goto error;
  63         }
  64
  65         switch (seek_t) {
  66         case LTTNG_VIEWER_SEEK_BEGINNING:
  67                 vstream->current_tracefile_id = stream->oldest_tracefile_id;
  68                 break;
  69         case LTTNG_VIEWER_SEEK_LAST:
  70                 vstream->current_tracefile_id = stream->current_tracefile_id;
  71                 break;
  72         default:
  73                 goto error;
  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 we never received an index for the current stream, delay the opening
  84          * of the index, otherwise open it right now.
  85          */
  86         if (vstream->current_tracefile_id == stream->current_tracefile_id
  87                         && stream->total_index_received == 0) {
  88                 vstream->index_fd = NULL;
  89         } else {
  90                 int read_fd;
  91
  92                 read_fd = index_open(vstream->path_name, vstream->channel_name,
  93                                 stream->tracefile_count,
  94                                 vstream->current_tracefile_id);
  95                 if (read_fd < 0) {
  96                         goto error_unlock;
  97                 }
  98                 vstream->index_fd = stream_fd_create(read_fd);
  99                 if (!vstream->index_fd) {
 100                         if (close(read_fd)) {
 101                                 PERROR("close");
 102                         }
 103                         goto error_unlock;
 104                 }
 105         }
 106
 107         if (seek_t == LTTNG_VIEWER_SEEK_LAST && vstream->index_fd) {
 108                 off_t lseek_ret;
 109
 110                 lseek_ret = lseek(vstream->index_fd->fd, 0, SEEK_END);
 111                 if (lseek_ret < 0) {
 112                         goto error_unlock;
 113                 }
 114                 vstream->last_sent_index = stream->total_index_received;
 115         }
 116         pthread_mutex_unlock(&stream->lock);
 117
 118         if (stream->is_metadata) {
 119                 rcu_assign_pointer(stream->trace->viewer_metadata_stream,
 120                                 vstream);
 121         }
 122
 123         /* Globally visible after the add unique. */
 124         lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
 125         lttng_ht_add_unique_u64(viewer_streams_ht, &vstream->stream_n);
 126
 127         pthread_mutex_init(&vstream->reflock, NULL);
 128         urcu_ref_init(&vstream->ref);
 129
 130         return vstream;
 131
 132 error_unlock:
 133         pthread_mutex_unlock(&stream->lock);
 134 error:
 135         if (vstream) {
 136                 viewer_stream_destroy(vstream);
 137         }
 138         return NULL;
 139 }
 140
 141 static void viewer_stream_unpublish(struct relay_viewer_stream *vstream)
 142 {
 143         int ret;
 144         struct lttng_ht_iter iter;
 145
 146         iter.iter.node = &vstream->stream_n.node;
 147         ret = lttng_ht_del(viewer_streams_ht, &iter);
 148         assert(!ret);
 149 }
 150
 151 static void viewer_stream_release(struct urcu_ref *ref)
 152 {
 153         struct relay_viewer_stream *vstream = caa_container_of(ref,
 154                         struct relay_viewer_stream, ref);
 155
 156         if (vstream->stream->is_metadata) {
 157                 rcu_assign_pointer(vstream->stream->trace->viewer_metadata_stream, NULL);
 158         }
 159
 160         viewer_stream_unpublish(vstream);
 161
 162         if (vstream->stream_fd) {
 163                 stream_fd_put(vstream->stream_fd);
 164                 vstream->stream_fd = NULL;
 165         }
 166         if (vstream->index_fd) {
 167                 stream_fd_put(vstream->index_fd);
 168                 vstream->index_fd = NULL;
 169         }
 170         if (vstream->stream) {
 171                 stream_put(vstream->stream);
 172                 vstream->stream = NULL;
 173         }
 174         call_rcu(&vstream->rcu_node, viewer_stream_destroy_rcu);
 175 }
 176
 177 /* Must be called with RCU read-side lock held. */
 178 bool viewer_stream_get(struct relay_viewer_stream *vstream)
 179 {
 180         bool has_ref = false;
 181
 182         pthread_mutex_lock(&vstream->reflock);
 183         if (vstream->ref.refcount != 0) {
 184                 has_ref = true;
 185                 urcu_ref_get(&vstream->ref);
 186         }
 187         pthread_mutex_unlock(&vstream->reflock);
 188
 189         return has_ref;
 190 }
 191
 192 /*
 193  * Get viewer stream by id.
 194  *
 195  * Return viewer stream if found else NULL.
 196  */
 197 struct relay_viewer_stream *viewer_stream_get_by_id(uint64_t id)
 198 {
 199         struct lttng_ht_node_u64 *node;
 200         struct lttng_ht_iter iter;
 201         struct relay_viewer_stream *vstream = NULL;
 202
 203         rcu_read_lock();
 204         lttng_ht_lookup(viewer_streams_ht, &id, &iter);
 205         node = lttng_ht_iter_get_node_u64(&iter);
 206         if (!node) {
 207                 DBG("Relay viewer stream %" PRIu64 " not found", id);
 208                 goto end;
 209         }
 210         vstream = caa_container_of(node, struct relay_viewer_stream, stream_n);
 211         if (!viewer_stream_get(vstream)) {
 212                 vstream = NULL;
 213         }
 214 end:
 215         rcu_read_unlock();
 216         return vstream;
 217 }
 218
 219 void viewer_stream_put(struct relay_viewer_stream *vstream)
 220 {
 221         rcu_read_lock();
 222         pthread_mutex_lock(&vstream->reflock);
 223         urcu_ref_put(&vstream->ref, viewer_stream_release);
 224         pthread_mutex_unlock(&vstream->reflock);
 225         rcu_read_unlock();
 226 }
 227
 228 /*
 229  * Returns whether the current tracefile is readable. If not, it has
 230  * been overwritten.
 231  * Must be called with rstream lock held.
 232  */
 233 bool viewer_stream_is_tracefile_seq_readable(struct relay_viewer_stream *vstream,
 234                  uint64_t seq)
 235 {
 236         struct relay_stream *stream = vstream->stream;
 237
 238         if (seq >= stream->oldest_tracefile_seq
 239                         && seq <= stream->current_tracefile_seq) {
 240                 /* seq is a readable file. */
 241                 return true;
 242         } else {
 243                 /* seq is not readable. */
 244                 return false;
 245         }
 246 }
 247
 248 /*
 249  * Rotate a stream to the next tracefile.
 250  *
 251  * Must be called with the rstream lock held.
 252  * Returns 0 on success, 1 on EOF, a negative value on error.
 253  */
 254 int viewer_stream_rotate(struct relay_viewer_stream *vstream)
 255 {
 256         int ret;
 257         struct relay_stream *stream = vstream->stream;
 258
 259         /* Detect the last tracefile to open. */
 260         if (stream->total_index_received == vstream->last_sent_index
 261                         && stream->trace->session->connection_closed) {
 262                 ret = 1;
 263                 goto end;
 264         }
 265
 266         if (stream->tracefile_count == 0) {
 267                 /* Ignore rotation, there is none to do. */
 268                 ret = 0;
 269                 goto end;
 270         }
 271
 272         if (!viewer_stream_is_tracefile_seq_readable(vstream,
 273                         vstream->current_tracefile_seq + 1)) {
 274                 vstream->current_tracefile_id =
 275                                 stream->oldest_tracefile_id;
 276                 vstream->current_tracefile_seq =
 277                                 stream->oldest_tracefile_seq;
 278         } else {
 279                 vstream->current_tracefile_id =
 280                                 (vstream->current_tracefile_id + 1)
 281                                         % stream->tracefile_count;
 282                 vstream->current_tracefile_seq++;
 283         }
 284
 285         if (vstream->index_fd) {
 286                 stream_fd_put(vstream->index_fd);
 287                 vstream->index_fd = NULL;
 288         }
 289         if (vstream->stream_fd) {
 290                 stream_fd_put(vstream->stream_fd);
 291                 vstream->stream_fd = NULL;
 292         }
 293
 294         ret = index_open(vstream->path_name, vstream->channel_name,
 295                         stream->tracefile_count,
 296                         vstream->current_tracefile_id);
 297         if (ret < 0) {
 298                 goto end;
 299         }
 300         vstream->index_fd = stream_fd_create(ret);
 301         if (vstream->index_fd) {
 302                 ret = 0;
 303         } else {
 304                 if (close(ret)) {
 305                         PERROR("close");
 306                 }
 307                 ret = -1;
 308         }
 309 end:
 310         return ret;
 311 }
 312
 313 void print_viewer_streams(void)
 314 {
 315         struct lttng_ht_iter iter;
 316         struct relay_viewer_stream *vstream;
 317
 318         rcu_read_lock();
 319         cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
 320                         stream_n.node) {
 321                 if (!viewer_stream_get(vstream)) {
 322                         continue;
 323                 }
 324                 DBG("vstream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
 325                         " session %" PRIu64,
 326                         vstream,
 327                         vstream->ref.refcount,
 328                         vstream->stream->stream_handle,
 329                         vstream->stream->trace->id,
 330                         vstream->stream->trace->session->id);
 331                 viewer_stream_put(vstream);
 332         }
 333         rcu_read_unlock();
 334 }