src/bin/lttng-relayd/viewer-stream.c

   1 /*
   2  * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
   3  *                      David Goulet <dgoulet@efficios.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License, version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  12  * more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along with
  15  * this program; if not, write to the Free Software Foundation, Inc., 51
  16  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <common/common.h>
  21 #include <common/index/index.h>
  22
  23 #include "lttng-relayd.h"
  24 #include "viewer-stream.h"
  25
  26 static void free_stream(struct relay_viewer_stream *stream)
  27 {
  28         assert(stream);
  29
  30         free(stream->path_name);
  31         free(stream->channel_name);
  32         free(stream);
  33 }
  34
  35 static void deferred_free_viewer_stream(struct rcu_head *head)
  36 {
  37         struct relay_viewer_stream *stream =
  38                 caa_container_of(head, struct relay_viewer_stream, rcu_node);
  39
  40         free_stream(stream);
  41 }
  42
  43 struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
  44                 enum lttng_viewer_seek seek_t, struct ctf_trace *ctf_trace)
  45 {
  46         struct relay_viewer_stream *vstream;
  47
  48         assert(stream);
  49         assert(ctf_trace);
  50
  51         vstream = zmalloc(sizeof(*vstream));
  52         if (!vstream) {
  53                 PERROR("relay viewer stream zmalloc");
  54                 goto error;
  55         }
  56
  57         vstream->session_id = stream->session_id;
  58         vstream->stream_handle = stream->stream_handle;
  59         vstream->path_name = strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX);
  60         if (vstream->path_name == NULL) {
  61                 PERROR("relay viewer path_name alloc");
  62                 goto error;
  63         }
  64         vstream->channel_name = strndup(stream->channel_name,
  65                         LTTNG_VIEWER_NAME_MAX);
  66         if (vstream->channel_name == NULL) {
  67                 PERROR("relay viewer channel_name alloc");
  68                 goto error;
  69         }
  70         vstream->tracefile_count = stream->tracefile_count;
  71         vstream->metadata_flag = stream->metadata_flag;
  72         vstream->tracefile_count_last = -1ULL;
  73
  74         switch (seek_t) {
  75         case LTTNG_VIEWER_SEEK_BEGINNING:
  76                 vstream->tracefile_count_current = stream->oldest_tracefile_id;
  77                 break;
  78         case LTTNG_VIEWER_SEEK_LAST:
  79                 vstream->tracefile_count_current = stream->tracefile_count_current;
  80                 break;
  81         default:
  82                 assert(0);
  83                 goto error;
  84         }
  85
  86         if (vstream->metadata_flag) {
  87                 ctf_trace->viewer_metadata_stream = vstream;
  88         }
  89
  90         /* Globally visible after the add unique. */
  91         lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
  92         lttng_ht_add_unique_u64(viewer_streams_ht, &vstream->stream_n);
  93
  94         vstream->index_read_fd = -1;
  95         vstream->read_fd = -1;
  96
  97         /*
  98          * This is to avoid a race between the initialization of this object and
  99          * the close of the given stream. If the stream is unable to find this
 100          * viewer stream when closing, this copy will at least take the latest
 101          * value. We also need that for the seek_last.
 102          */
 103         vstream->total_index_received = stream->total_index_received;
 104
 105         /*
 106          * If we never received an index for the current stream, delay the opening
 107          * of the index, otherwise open it right now.
 108          */
 109         if (vstream->tracefile_count_current == stream->tracefile_count_current
 110                         && vstream->total_index_received == 0) {
 111                 vstream->index_read_fd = -1;
 112         } else {
 113                 int read_fd;
 114
 115                 read_fd = index_open(vstream->path_name, vstream->channel_name,
 116                                 vstream->tracefile_count, vstream->tracefile_count_current);
 117                 if (read_fd < 0) {
 118                         goto error;
 119                 }
 120                 vstream->index_read_fd = read_fd;
 121         }
 122
 123         if (seek_t == LTTNG_VIEWER_SEEK_LAST && vstream->index_read_fd >= 0) {
 124                 off_t lseek_ret;
 125
 126                 lseek_ret = lseek(vstream->index_read_fd,
 127                                 vstream->total_index_received * sizeof(struct ctf_packet_index),
 128                                 SEEK_CUR);
 129                 if (lseek_ret < 0) {
 130                         goto error;
 131                 }
 132                 vstream->last_sent_index = vstream->total_index_received;
 133         }
 134
 135         return vstream;
 136
 137 error:
 138         if (vstream) {
 139                 free_stream(vstream);
 140         }
 141         return NULL;
 142 }
 143
 144 void viewer_stream_delete(struct relay_viewer_stream *stream)
 145 {
 146         int ret;
 147         struct lttng_ht_iter iter;
 148
 149         iter.iter.node = &stream->stream_n.node;
 150         ret = lttng_ht_del(viewer_streams_ht, &iter);
 151         assert(!ret);
 152 }
 153
 154 void viewer_stream_destroy(struct ctf_trace *ctf_trace,
 155                 struct relay_viewer_stream *stream)
 156 {
 157         int ret;
 158
 159         assert(stream);
 160
 161         if (ctf_trace) {
 162                 ctf_trace_put_ref(ctf_trace);
 163         }
 164
 165         if (stream->read_fd >= 0) {
 166                 ret = close(stream->read_fd);
 167                 if (ret < 0) {
 168                         PERROR("close read_fd");
 169                 }
 170         }
 171         if (stream->index_read_fd >= 0) {
 172                 ret = close(stream->index_read_fd);
 173                 if (ret < 0) {
 174                         PERROR("close index_read_fd");
 175                 }
 176         }
 177
 178         call_rcu(&stream->rcu_node, deferred_free_viewer_stream);
 179 }
 180
 181 /*
 182  * Find viewer stream by id. RCU read side lock MUST be acquired.
 183  *
 184  * Return stream if found else NULL.
 185  */
 186 struct relay_viewer_stream *viewer_stream_find_by_id(uint64_t id)
 187 {
 188         struct lttng_ht_node_u64 *node;
 189         struct lttng_ht_iter iter;
 190         struct relay_viewer_stream *stream = NULL;
 191
 192         lttng_ht_lookup(viewer_streams_ht, &id, &iter);
 193         node = lttng_ht_iter_get_node_u64(&iter);
 194         if (!node) {
 195                 DBG("Relay viewer stream %" PRIu64 " not found", id);
 196                 goto end;
 197         }
 198         stream = caa_container_of(node, struct relay_viewer_stream, stream_n);
 199
 200 end:
 201         return stream;
 202 }
 203
 204 /*
 205  * Rotate a stream to the next tracefile.
 206  *
 207  * Must be called with viewer_stream_rotation_lock held.
 208  * Returns 0 on success, 1 on EOF, a negative value on error.
 209  */
 210 int viewer_stream_rotate(struct relay_viewer_stream *vstream,
 211                 struct relay_stream *stream)
 212 {
 213         int ret;
 214         uint64_t tracefile_id;
 215
 216         assert(vstream);
 217         assert(stream);
 218
 219         if (vstream->tracefile_count == 0) {
 220                 /* Ignore rotation, there is none to do. */
 221                 ret = 0;
 222                 goto end;
 223         }
 224
 225         tracefile_id = (vstream->tracefile_count_current + 1) %
 226                 vstream->tracefile_count;
 227
 228         /* Detect the last tracefile to open. */
 229         if (vstream->tracefile_count_last != -1ULL &&
 230                         vstream->tracefile_count_last ==
 231                         vstream->tracefile_count_current) {
 232                 ret = 1;
 233                 goto end;
 234         }
 235
 236         /*
 237          * The writer and the reader are not working in the same tracefile, we can
 238          * read up to EOF, we don't care about the total_index_received.
 239          */
 240         if (stream->close_flag || (stream->tracefile_count_current != tracefile_id)) {
 241                 vstream->close_write_flag = 1;
 242         } else {
 243                 /*
 244                  * We are opening a file that is still open in write, make sure we
 245                  * limit our reading to the number of indexes received.
 246                  */
 247                 vstream->close_write_flag = 0;
 248                 if (stream->close_flag) {
 249                         vstream->total_index_received = stream->total_index_received;
 250                 }
 251         }
 252         vstream->tracefile_count_current = tracefile_id;
 253
 254         ret = close(vstream->index_read_fd);
 255         if (ret < 0) {
 256                 PERROR("close index file %d", vstream->index_read_fd);
 257         }
 258         vstream->index_read_fd = -1;
 259
 260         ret = close(vstream->read_fd);
 261         if (ret < 0) {
 262                 PERROR("close tracefile %d", vstream->read_fd);
 263         }
 264         vstream->read_fd = -1;
 265
 266         pthread_mutex_lock(&vstream->overwrite_lock);
 267         vstream->abort_flag = 0;
 268         pthread_mutex_unlock(&vstream->overwrite_lock);
 269
 270         ret = index_open(vstream->path_name, vstream->channel_name,
 271                         vstream->tracefile_count, vstream->tracefile_count_current);
 272         if (ret < 0) {
 273                 goto error;
 274         }
 275         vstream->index_read_fd = ret;
 276
 277         ret = 0;
 278
 279 end:
 280 error:
 281         return ret;
 282 }