Fix: don't perform an automatic session rotation in snapshot mode
[lttng-tools.git] / src / bin / lttng-relayd / viewer-stream.c
CommitLineData
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1/*
2 * Copyright (C) 2013 - Julien Desfossez <jdesfossez@efficios.com>
3 * David Goulet <dgoulet@efficios.com>
7591bab1 4 * 2015 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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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
6c1c0768 20#define _LGPL_SOURCE
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21#include <common/common.h>
22#include <common/index/index.h>
f5436bfc 23#include <common/compat/string.h>
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24
25#include "lttng-relayd.h"
26#include "viewer-stream.h"
27
7591bab1 28static void viewer_stream_destroy(struct relay_viewer_stream *vstream)
2f8f53af 29{
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30 free(vstream->path_name);
31 free(vstream->channel_name);
32 free(vstream);
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33}
34
7591bab1 35static void viewer_stream_destroy_rcu(struct rcu_head *head)
2f8f53af 36{
7591bab1 37 struct relay_viewer_stream *vstream =
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38 caa_container_of(head, struct relay_viewer_stream, rcu_node);
39
7591bab1 40 viewer_stream_destroy(vstream);
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41}
42
43struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
7591bab1 44 enum lttng_viewer_seek seek_t)
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45{
46 struct relay_viewer_stream *vstream;
47
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48 vstream = zmalloc(sizeof(*vstream));
49 if (!vstream) {
50 PERROR("relay viewer stream zmalloc");
51 goto error;
52 }
53
f5436bfc 54 vstream->path_name = lttng_strndup(stream->path_name, LTTNG_VIEWER_PATH_MAX);
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55 if (vstream->path_name == NULL) {
56 PERROR("relay viewer path_name alloc");
57 goto error;
58 }
f5436bfc 59 vstream->channel_name = lttng_strndup(stream->channel_name,
2f8f53af 60 LTTNG_VIEWER_NAME_MAX);
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61 if (vstream->channel_name == NULL) {
62 PERROR("relay viewer channel_name alloc");
63 goto error;
64 }
2f8f53af 65
a44ca2ca
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66 if (!stream_get(stream)) {
67 ERR("Cannot get stream");
68 goto error;
69 }
70 vstream->stream = stream;
71
72 pthread_mutex_lock(&stream->lock);
73
74 if (stream->is_metadata && stream->trace->viewer_metadata_stream) {
75 ERR("Cannot attach viewer metadata stream to trace (busy).");
76 goto error_unlock;
77 }
78
2f8f53af 79 switch (seek_t) {
c4e361a4 80 case LTTNG_VIEWER_SEEK_BEGINNING:
a44ca2ca
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81 {
82 uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
83
84 if (seq_tail == -1ULL) {
85 /*
86 * Tail may not be initialized yet. Nonetheless, we know
87 * we want to send the first index once it becomes
88 * available.
89 */
90 seq_tail = 0;
91 }
92 vstream->current_tracefile_id =
93 tracefile_array_get_file_index_tail(stream->tfa);
94 vstream->index_sent_seqcount = seq_tail;
2f8f53af 95 break;
a44ca2ca 96 }
c4e361a4 97 case LTTNG_VIEWER_SEEK_LAST:
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98 vstream->current_tracefile_id =
99 tracefile_array_get_file_index_head(stream->tfa);
100 /*
101 * We seek at the very end of each stream, awaiting for
102 * a future packet to eventually come in.
103 *
104 * We don't need to check the head position for -1ULL since the
105 * increment will set it to 0.
106 */
107 vstream->index_sent_seqcount =
108 tracefile_array_get_seq_head(stream->tfa) + 1;
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109 break;
110 default:
a44ca2ca 111 goto error_unlock;
2f8f53af 112 }
2f8f53af 113
2f8f53af 114 /*
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115 * If we never received an index for the current stream, delay
116 * the opening of the index, otherwise open it right now.
2f8f53af 117 */
a44ca2ca 118 if (stream->index_received_seqcount == 0) {
f8f3885c 119 vstream->index_file = NULL;
2f8f53af 120 } else {
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121 vstream->index_file = lttng_index_file_open(vstream->path_name,
122 vstream->channel_name,
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123 stream->tracefile_count,
124 vstream->current_tracefile_id);
f8f3885c 125 if (!vstream->index_file) {
7591bab1 126 goto error_unlock;
2f8f53af 127 }
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128 }
129
f8f3885c 130 if (seek_t == LTTNG_VIEWER_SEEK_LAST && vstream->index_file) {
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131 off_t lseek_ret;
132
f8f3885c 133 lseek_ret = lseek(vstream->index_file->fd, 0, SEEK_END);
2f8f53af 134 if (lseek_ret < 0) {
7591bab1 135 goto error_unlock;
2f8f53af 136 }
7591bab1 137 }
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138 if (stream->is_metadata) {
139 rcu_assign_pointer(stream->trace->viewer_metadata_stream,
140 vstream);
2f8f53af 141 }
a44ca2ca 142 pthread_mutex_unlock(&stream->lock);
2f8f53af 143
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144 /* Globally visible after the add unique. */
145 lttng_ht_node_init_u64(&vstream->stream_n, stream->stream_handle);
146 lttng_ht_add_unique_u64(viewer_streams_ht, &vstream->stream_n);
147
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148 urcu_ref_init(&vstream->ref);
149
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150 return vstream;
151
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152error_unlock:
153 pthread_mutex_unlock(&stream->lock);
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154error:
155 if (vstream) {
7591bab1 156 viewer_stream_destroy(vstream);
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157 }
158 return NULL;
159}
160
7591bab1 161static void viewer_stream_unpublish(struct relay_viewer_stream *vstream)
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162{
163 int ret;
164 struct lttng_ht_iter iter;
165
7591bab1 166 iter.iter.node = &vstream->stream_n.node;
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167 ret = lttng_ht_del(viewer_streams_ht, &iter);
168 assert(!ret);
169}
170
7591bab1 171static void viewer_stream_release(struct urcu_ref *ref)
2f8f53af 172{
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173 struct relay_viewer_stream *vstream = caa_container_of(ref,
174 struct relay_viewer_stream, ref);
2a174661 175
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176 if (vstream->stream->is_metadata) {
177 rcu_assign_pointer(vstream->stream->trace->viewer_metadata_stream, NULL);
2a174661 178 }
2f8f53af 179
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180 viewer_stream_unpublish(vstream);
181
182 if (vstream->stream_fd) {
183 stream_fd_put(vstream->stream_fd);
184 vstream->stream_fd = NULL;
2f8f53af 185 }
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186 if (vstream->index_file) {
187 lttng_index_file_put(vstream->index_file);
188 vstream->index_file = NULL;
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189 }
190 if (vstream->stream) {
191 stream_put(vstream->stream);
192 vstream->stream = NULL;
193 }
194 call_rcu(&vstream->rcu_node, viewer_stream_destroy_rcu);
195}
196
197/* Must be called with RCU read-side lock held. */
198bool viewer_stream_get(struct relay_viewer_stream *vstream)
199{
ce4d4083 200 return urcu_ref_get_unless_zero(&vstream->ref);
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201}
202
203/*
7591bab1 204 * Get viewer stream by id.
2f8f53af 205 *
7591bab1 206 * Return viewer stream if found else NULL.
2f8f53af 207 */
7591bab1 208struct relay_viewer_stream *viewer_stream_get_by_id(uint64_t id)
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209{
210 struct lttng_ht_node_u64 *node;
211 struct lttng_ht_iter iter;
7591bab1 212 struct relay_viewer_stream *vstream = NULL;
2f8f53af 213
7591bab1 214 rcu_read_lock();
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215 lttng_ht_lookup(viewer_streams_ht, &id, &iter);
216 node = lttng_ht_iter_get_node_u64(&iter);
217 if (!node) {
218 DBG("Relay viewer stream %" PRIu64 " not found", id);
219 goto end;
220 }
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221 vstream = caa_container_of(node, struct relay_viewer_stream, stream_n);
222 if (!viewer_stream_get(vstream)) {
223 vstream = NULL;
224 }
2f8f53af 225end:
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226 rcu_read_unlock();
227 return vstream;
228}
229
230void viewer_stream_put(struct relay_viewer_stream *vstream)
231{
232 rcu_read_lock();
7591bab1 233 urcu_ref_put(&vstream->ref, viewer_stream_release);
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234 rcu_read_unlock();
235}
236
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237/*
238 * Rotate a stream to the next tracefile.
239 *
7591bab1 240 * Must be called with the rstream lock held.
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241 * Returns 0 on success, 1 on EOF, a negative value on error.
242 */
7591bab1 243int viewer_stream_rotate(struct relay_viewer_stream *vstream)
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244{
245 int ret;
7591bab1 246 struct relay_stream *stream = vstream->stream;
a44ca2ca 247 uint64_t new_id;
2f8f53af 248
7591bab1 249 /* Detect the last tracefile to open. */
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250 if (stream->index_received_seqcount
251 == vstream->index_sent_seqcount
7591bab1
MD
252 && stream->trace->session->connection_closed) {
253 ret = 1;
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254 goto end;
255 }
2f8f53af 256
7591bab1
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257 if (stream->tracefile_count == 0) {
258 /* Ignore rotation, there is none to do. */
259 ret = 0;
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260 goto end;
261 }
262
a44ca2ca
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263 /*
264 * Try to move to the next file.
265 */
266 new_id = (vstream->current_tracefile_id + 1)
267 % stream->tracefile_count;
268 if (tracefile_array_seq_in_file(stream->tfa, new_id,
269 vstream->index_sent_seqcount)) {
270 vstream->current_tracefile_id = new_id;
2f8f53af 271 } else {
a44ca2ca
MD
272 uint64_t seq_tail = tracefile_array_get_seq_tail(stream->tfa);
273
274 /*
275 * This can only be reached on overwrite, which implies there
276 * has been data written at some point, which will have set the
277 * tail.
278 */
279 assert(seq_tail != -1ULL);
280 /*
281 * We need to resync because we lag behind tail.
282 */
7591bab1 283 vstream->current_tracefile_id =
a44ca2ca
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284 tracefile_array_get_file_index_tail(stream->tfa);
285 vstream->index_sent_seqcount = seq_tail;
2f8f53af 286 }
2f8f53af 287
f8f3885c
MD
288 if (vstream->index_file) {
289 lttng_index_file_put(vstream->index_file);
290 vstream->index_file = NULL;
2f8f53af 291 }
7591bab1
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292 if (vstream->stream_fd) {
293 stream_fd_put(vstream->stream_fd);
294 vstream->stream_fd = NULL;
2f8f53af 295 }
2f8f53af 296
f8f3885c
MD
297 vstream->index_file = lttng_index_file_open(vstream->path_name,
298 vstream->channel_name,
7591bab1
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299 stream->tracefile_count,
300 vstream->current_tracefile_id);
f8f3885c
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301 if (!vstream->index_file) {
302 ret = -1;
7591bab1 303 goto end;
7591bab1 304 } else {
f8f3885c 305 ret = 0;
2f8f53af 306 }
2f8f53af 307end:
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308 return ret;
309}
7591bab1
MD
310
311void print_viewer_streams(void)
312{
313 struct lttng_ht_iter iter;
314 struct relay_viewer_stream *vstream;
315
ce3f3ba3
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316 if (!viewer_streams_ht) {
317 return;
318 }
319
7591bab1
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320 rcu_read_lock();
321 cds_lfht_for_each_entry(viewer_streams_ht->ht, &iter.iter, vstream,
322 stream_n.node) {
323 if (!viewer_stream_get(vstream)) {
324 continue;
325 }
326 DBG("vstream %p refcount %ld stream %" PRIu64 " trace %" PRIu64
327 " session %" PRIu64,
328 vstream,
329 vstream->ref.refcount,
330 vstream->stream->stream_handle,
331 vstream->stream->trace->id,
332 vstream->stream->trace->session->id);
333 viewer_stream_put(vstream);
334 }
335 rcu_read_unlock();
336}
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