| 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) |
| 45 | { |
| 46 | struct relay_viewer_stream *vstream; |
| 47 | |
| 48 | assert(stream); |
| 49 | |
| 50 | vstream = zmalloc(sizeof(*vstream)); |
| 51 | if (!vstream) { |
| 52 | PERROR("relay viewer stream zmalloc"); |
| 53 | goto error; |
| 54 | } |
| 55 | |
| 56 | vstream->session_id = stream->session->id; |
| 57 | vstream->stream_handle = stream->stream_handle; |
| 58 | vstream->path_name = strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX); |
| 59 | vstream->channel_name = strndup(stream->channel_name, |
| 60 | LTTNG_VIEWER_NAME_MAX); |
| 61 | vstream->tracefile_count = stream->tracefile_count; |
| 62 | vstream->metadata_flag = stream->metadata_flag; |
| 63 | vstream->tracefile_count_last = -1ULL; |
| 64 | |
| 65 | switch (seek_t) { |
| 66 | case VIEWER_SEEK_BEGINNING: |
| 67 | vstream->tracefile_count_current = stream->oldest_tracefile_id; |
| 68 | break; |
| 69 | case VIEWER_SEEK_LAST: |
| 70 | vstream->tracefile_count_current = stream->tracefile_count_current; |
| 71 | break; |
| 72 | default: |
| 73 | assert(0); |
| 74 | goto error; |
| 75 | } |
| 76 | |
| 77 | vstream->ctf_trace = stream->ctf_trace; |
| 78 | if (vstream->metadata_flag) { |
| 79 | vstream->ctf_trace->viewer_metadata_stream = vstream; |
| 80 | } |
| 81 | uatomic_inc(&vstream->ctf_trace->refcount); |
| 82 | |
| 83 | /* Globally visible after the add unique. */ |
| 84 | lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle); |
| 85 | lttng_ht_add_unique_u64(viewer_streams_ht, &vstream->stream_n); |
| 86 | |
| 87 | vstream->index_read_fd = -1; |
| 88 | vstream->read_fd = -1; |
| 89 | |
| 90 | /* |
| 91 | * This is to avoid a race between the initialization of this object and |
| 92 | * the close of the given stream. If the stream is unable to find this |
| 93 | * viewer stream when closing, this copy will at least take the latest |
| 94 | * value. We also need that for the seek_last. |
| 95 | */ |
| 96 | vstream->total_index_received = stream->total_index_received; |
| 97 | |
| 98 | /* |
| 99 | * If we never received an index for the current stream, delay the opening |
| 100 | * of the index, otherwise open it right now. |
| 101 | */ |
| 102 | if (vstream->tracefile_count_current == stream->tracefile_count_current |
| 103 | && vstream->total_index_received == 0) { |
| 104 | vstream->index_read_fd = -1; |
| 105 | } else { |
| 106 | int read_fd; |
| 107 | |
| 108 | read_fd = index_open(vstream->path_name, vstream->channel_name, |
| 109 | vstream->tracefile_count, vstream->tracefile_count_current); |
| 110 | if (read_fd < 0) { |
| 111 | goto error; |
| 112 | } |
| 113 | vstream->index_read_fd = read_fd; |
| 114 | } |
| 115 | |
| 116 | if (seek_t == VIEWER_SEEK_LAST && vstream->index_read_fd >= 0) { |
| 117 | off_t lseek_ret; |
| 118 | |
| 119 | lseek_ret = lseek(vstream->index_read_fd, |
| 120 | vstream->total_index_received * sizeof(struct ctf_packet_index), |
| 121 | SEEK_CUR); |
| 122 | if (lseek_ret < 0) { |
| 123 | goto error; |
| 124 | } |
| 125 | vstream->last_sent_index = vstream->total_index_received; |
| 126 | } |
| 127 | |
| 128 | return vstream; |
| 129 | |
| 130 | error: |
| 131 | if (vstream) { |
| 132 | free_stream(vstream); |
| 133 | } |
| 134 | return NULL; |
| 135 | } |
| 136 | |
| 137 | void viewer_stream_delete(struct relay_viewer_stream *stream) |
| 138 | { |
| 139 | int ret; |
| 140 | struct lttng_ht_iter iter; |
| 141 | |
| 142 | iter.iter.node = &stream->stream_n.node; |
| 143 | ret = lttng_ht_del(viewer_streams_ht, &iter); |
| 144 | assert(!ret); |
| 145 | } |
| 146 | |
| 147 | void viewer_stream_destroy(struct relay_viewer_stream *stream) |
| 148 | { |
| 149 | int ret; |
| 150 | unsigned long ret_ref; |
| 151 | |
| 152 | assert(stream); |
| 153 | ret_ref = uatomic_add_return(&stream->ctf_trace->refcount, -1); |
| 154 | assert(ret_ref >= 0); |
| 155 | |
| 156 | if (stream->read_fd >= 0) { |
| 157 | ret = close(stream->read_fd); |
| 158 | if (ret < 0) { |
| 159 | PERROR("close read_fd"); |
| 160 | } |
| 161 | } |
| 162 | if (stream->index_read_fd >= 0) { |
| 163 | ret = close(stream->index_read_fd); |
| 164 | if (ret < 0) { |
| 165 | PERROR("close index_read_fd"); |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | /* |
| 170 | * If the only stream left in the HT is the metadata stream, |
| 171 | * we need to remove it because we won't detect a EOF for this |
| 172 | * stream. |
| 173 | */ |
| 174 | if (ret_ref == 1 && stream->ctf_trace->viewer_metadata_stream) { |
| 175 | viewer_stream_delete(stream->ctf_trace->viewer_metadata_stream); |
| 176 | viewer_stream_destroy(stream->ctf_trace->viewer_metadata_stream); |
| 177 | stream->ctf_trace->metadata_stream = NULL; |
| 178 | DBG("Freeing ctf_trace %" PRIu64, stream->ctf_trace->id); |
| 179 | /* |
| 180 | * The streaming-side is already closed and we can't receive a new |
| 181 | * stream concurrently at this point (since the session is being |
| 182 | * destroyed), so when we detect the refcount equals 0, we are the |
| 183 | * only owners of the ctf_trace and we can free it ourself. |
| 184 | */ |
| 185 | free(stream->ctf_trace); |
| 186 | } |
| 187 | |
| 188 | call_rcu(&stream->rcu_node, deferred_free_viewer_stream); |
| 189 | } |
| 190 | |
| 191 | /* |
| 192 | * Find viewer stream by id. RCU read side lock MUST be acquired. |
| 193 | * |
| 194 | * Return stream if found else NULL. |
| 195 | */ |
| 196 | struct relay_viewer_stream *viewer_stream_find_by_id(uint64_t id) |
| 197 | { |
| 198 | struct lttng_ht_node_u64 *node; |
| 199 | struct lttng_ht_iter iter; |
| 200 | struct relay_viewer_stream *stream = NULL; |
| 201 | |
| 202 | lttng_ht_lookup(viewer_streams_ht, &id, &iter); |
| 203 | node = lttng_ht_iter_get_node_u64(&iter); |
| 204 | if (!node) { |
| 205 | DBG("Relay viewer stream %" PRIu64 " not found", id); |
| 206 | goto end; |
| 207 | } |
| 208 | stream = caa_container_of(node, struct relay_viewer_stream, stream_n); |
| 209 | |
| 210 | end: |
| 211 | return stream; |
| 212 | } |
| 213 | |
| 214 | /* |
| 215 | * Rotate a stream to the next tracefile. |
| 216 | * |
| 217 | * Returns 0 on success, 1 on EOF, a negative value on error. |
| 218 | */ |
| 219 | int viewer_stream_rotate(struct relay_viewer_stream *vstream, |
| 220 | struct relay_stream *stream) |
| 221 | { |
| 222 | int ret; |
| 223 | uint64_t tracefile_id; |
| 224 | |
| 225 | assert(vstream); |
| 226 | |
| 227 | tracefile_id = (vstream->tracefile_count_current + 1) % |
| 228 | vstream->tracefile_count; |
| 229 | |
| 230 | /* Detect the last tracefile to open. */ |
| 231 | if (vstream->tracefile_count_last != -1ULL && |
| 232 | vstream->tracefile_count_last == |
| 233 | vstream->tracefile_count_current) { |
| 234 | ret = 1; |
| 235 | goto end; |
| 236 | } |
| 237 | |
| 238 | /* |
| 239 | * If the stream on the streaming side still exists, lock to execute |
| 240 | * rotation in order to avoid races between a modification on the index |
| 241 | * values. |
| 242 | */ |
| 243 | if (stream) { |
| 244 | pthread_mutex_lock(&stream->viewer_stream_rotation_lock); |
| 245 | } |
| 246 | |
| 247 | /* |
| 248 | * The writer and the reader are not working in the same tracefile, we can |
| 249 | * read up to EOF, we don't care about the total_index_received. |
| 250 | */ |
| 251 | if (!stream || (stream->tracefile_count_current != tracefile_id)) { |
| 252 | vstream->close_write_flag = 1; |
| 253 | } else { |
| 254 | /* |
| 255 | * We are opening a file that is still open in write, make sure we |
| 256 | * limit our reading to the number of indexes received. |
| 257 | */ |
| 258 | vstream->close_write_flag = 0; |
| 259 | if (stream) { |
| 260 | vstream->total_index_received = stream->total_index_received; |
| 261 | } |
| 262 | } |
| 263 | vstream->tracefile_count_current = tracefile_id; |
| 264 | |
| 265 | ret = close(vstream->index_read_fd); |
| 266 | if (ret < 0) { |
| 267 | PERROR("close index file %d", vstream->index_read_fd); |
| 268 | } |
| 269 | vstream->index_read_fd = -1; |
| 270 | |
| 271 | ret = close(vstream->read_fd); |
| 272 | if (ret < 0) { |
| 273 | PERROR("close tracefile %d", vstream->read_fd); |
| 274 | } |
| 275 | vstream->read_fd = -1; |
| 276 | |
| 277 | pthread_mutex_lock(&vstream->overwrite_lock); |
| 278 | vstream->abort_flag = 0; |
| 279 | pthread_mutex_unlock(&vstream->overwrite_lock); |
| 280 | |
| 281 | if (stream) { |
| 282 | pthread_mutex_unlock(&stream->viewer_stream_rotation_lock); |
| 283 | } |
| 284 | |
| 285 | ret = index_open(vstream->path_name, vstream->channel_name, |
| 286 | vstream->tracefile_count, vstream->tracefile_count_current); |
| 287 | if (ret < 0) { |
| 288 | goto error; |
| 289 | } |
| 290 | vstream->index_read_fd = ret; |
| 291 | |
| 292 | ret = 0; |
| 293 | |
| 294 | end: |
| 295 | error: |
| 296 | return ret; |
| 297 | } |