Implement support for lttng-modules syscall filtering
[lttng-tools.git] / src / common / consumer-metadata-cache.c
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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
6 * it under the terms of the GNU General Public License, version 2 only,
7 * as 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
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
17 */
18
19#define _GNU_SOURCE
20#include <assert.h>
21#include <pthread.h>
22#include <stdlib.h>
23#include <string.h>
24#include <sys/types.h>
25#include <unistd.h>
26#include <inttypes.h>
27
28#include <common/common.h>
29#include <common/utils.h>
30#include <common/sessiond-comm/sessiond-comm.h>
31#include <common/ust-consumer/ust-consumer.h>
32#include <common/consumer.h>
33
34#include "consumer-metadata-cache.h"
35
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36extern struct lttng_consumer_global_data consumer_data;
37
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38/*
39 * Extend the allocated size of the metadata cache. Called only from
40 * lttng_ustconsumer_write_metadata_cache.
41 *
42 * Return 0 on success, a negative value on error.
43 */
44static int extend_metadata_cache(struct lttng_consumer_channel *channel,
45 unsigned int size)
46{
47 int ret = 0;
48 char *tmp_data_ptr;
53efb85a 49 unsigned int new_size, old_size;
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50
51 assert(channel);
52 assert(channel->metadata_cache);
53
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54 old_size = channel->metadata_cache->cache_alloc_size;
55 new_size = max_t(unsigned int, old_size + size, old_size << 1);
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56 DBG("Extending metadata cache to %u", new_size);
57 tmp_data_ptr = realloc(channel->metadata_cache->data, new_size);
58 if (!tmp_data_ptr) {
59 ERR("Reallocating metadata cache");
60 free(channel->metadata_cache->data);
61 ret = -1;
62 goto end;
63 }
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64 /* Zero newly allocated memory */
65 memset(tmp_data_ptr + old_size, 0, new_size - old_size);
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66 channel->metadata_cache->data = tmp_data_ptr;
67 channel->metadata_cache->cache_alloc_size = new_size;
68
69end:
70 return ret;
71}
72
73/*
74 * Write metadata to the cache, extend the cache if necessary. We support
75 * non-contiguous updates but not overlapping ones. If there is contiguous
76 * metadata in the cache, we send it to the ring buffer. The metadata cache
77 * lock MUST be acquired to write in the cache.
78 *
79 * Return 0 on success, a negative value on error.
80 */
81int consumer_metadata_cache_write(struct lttng_consumer_channel *channel,
82 unsigned int offset, unsigned int len, char *data)
83{
84 int ret = 0;
6cd525e8 85 int size_ret;
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86 struct consumer_metadata_cache *cache;
87
88 assert(channel);
89 assert(channel->metadata_cache);
90
91 cache = channel->metadata_cache;
92 DBG("Writing %u bytes from offset %u in metadata cache", len, offset);
93
94 if (offset + len > cache->cache_alloc_size) {
95 ret = extend_metadata_cache(channel,
96 len - cache->cache_alloc_size + offset);
97 if (ret < 0) {
98 ERR("Extending metadata cache");
99 goto end;
100 }
101 }
102
103 memcpy(cache->data + offset, data, len);
104 cache->total_bytes_written += len;
105 if (offset + len > cache->max_offset) {
106 cache->max_offset = offset + len;
107 }
108
109 if (cache->max_offset == cache->total_bytes_written) {
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110 char dummy = 'c';
111
112 cache->contiguous = cache->max_offset;
113 if (channel->monitor) {
6cd525e8 114 size_ret = lttng_write(channel->metadata_stream->ust_metadata_poll_pipe[1],
04ef1097 115 &dummy, 1);
6cd525e8 116 if (size_ret < 1) {
04ef1097 117 ERR("Wakeup UST metadata pipe");
6cd525e8 118 ret = -1;
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119 goto end;
120 }
331744e3 121 }
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122 }
123
124end:
125 return ret;
126}
127
128/*
129 * Create the metadata cache, original allocated size: max_sb_size
130 *
131 * Return 0 on success, a negative value on error.
132 */
133int consumer_metadata_cache_allocate(struct lttng_consumer_channel *channel)
134{
135 int ret;
136
137 assert(channel);
138
139 channel->metadata_cache = zmalloc(
140 sizeof(struct consumer_metadata_cache));
141 if (!channel->metadata_cache) {
142 PERROR("zmalloc metadata cache struct");
143 ret = -1;
144 goto end;
145 }
146 ret = pthread_mutex_init(&channel->metadata_cache->lock, NULL);
147 if (ret != 0) {
148 PERROR("mutex init");
149 goto end_free_cache;
150 }
151
152 channel->metadata_cache->cache_alloc_size = DEFAULT_METADATA_CACHE_SIZE;
153 channel->metadata_cache->data = zmalloc(
154 channel->metadata_cache->cache_alloc_size * sizeof(char));
155 if (!channel->metadata_cache->data) {
156 PERROR("zmalloc metadata cache data");
157 ret = -1;
158 goto end_free_mutex;
159 }
160 DBG("Allocated metadata cache of %" PRIu64 " bytes",
161 channel->metadata_cache->cache_alloc_size);
162
163 ret = 0;
164 goto end;
165
166end_free_mutex:
167 pthread_mutex_destroy(&channel->metadata_cache->lock);
168end_free_cache:
169 free(channel->metadata_cache);
170end:
171 return ret;
172}
173
174/*
175 * Destroy and free the metadata cache
176 */
177void consumer_metadata_cache_destroy(struct lttng_consumer_channel *channel)
178{
179 if (!channel || !channel->metadata_cache) {
180 return;
181 }
182
183 DBG("Destroying metadata cache");
184
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185 pthread_mutex_destroy(&channel->metadata_cache->lock);
186 free(channel->metadata_cache->data);
187 free(channel->metadata_cache);
188}
189
190/*
191 * Check if the cache is flushed up to the offset passed in parameter.
192 *
193 * Return 0 if everything has been flushed, 1 if there is data not flushed.
194 */
195int consumer_metadata_cache_flushed(struct lttng_consumer_channel *channel,
5e41ebe1 196 uint64_t offset, int timer)
331744e3 197{
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198 int ret = 0;
199 struct lttng_consumer_stream *metadata_stream;
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200
201 assert(channel);
202 assert(channel->metadata_cache);
203
7f725ec5 204 /*
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205 * If not called from a timer handler, we have to take the
206 * channel lock to be mutually exclusive with channel teardown.
207 * Timer handler does not need to take this lock because it is
208 * already synchronized by timer stop (and, more importantly,
209 * taking this lock in a timer handler would cause a deadlock).
7f725ec5 210 */
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211 if (!timer) {
212 pthread_mutex_lock(&channel->lock);
213 }
ec6ea7d0 214 pthread_mutex_lock(&channel->timer_lock);
331744e3 215 pthread_mutex_lock(&channel->metadata_cache->lock);
fe81e5c9 216
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217 metadata_stream = channel->metadata_stream;
218
219 if (!metadata_stream) {
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220 /*
221 * Having no metadata stream means the channel is being destroyed so there
222 * is no cache to flush anymore.
223 */
224 ret = 0;
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225 } else if (metadata_stream->ust_metadata_pushed >= offset) {
226 ret = 0;
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227 } else if (channel->metadata_stream->endpoint_status !=
228 CONSUMER_ENDPOINT_ACTIVE) {
229 /* An inactive endpoint means we don't have to flush anymore. */
230 ret = 0;
331744e3 231 } else {
fe81e5c9 232 /* Still not completely flushed. */
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233 ret = 1;
234 }
fe81e5c9 235
331744e3 236 pthread_mutex_unlock(&channel->metadata_cache->lock);
ec6ea7d0 237 pthread_mutex_unlock(&channel->timer_lock);
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238 if (!timer) {
239 pthread_mutex_unlock(&channel->lock);
240 }
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241
242 return ret;
243}
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