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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define LOG_TAG "Trace"
#include <cutils/properties.h>
#include <utils/Log.h>
#include <utils/Trace.h>
#include <utils/misc.h>
namespace android {
volatile int32_t Tracer::sIsReady = 0;
int Tracer::sTraceFD = -1;
uint64_t Tracer::sEnabledTags = 0;
Mutex Tracer::sMutex;
void Tracer::changeCallback() {
Mutex::Autolock lock(sMutex);
if (sIsReady && sTraceFD >= 0) {
loadSystemProperty();
}
}
void Tracer::init() {
Mutex::Autolock lock(sMutex);
if (!sIsReady) {
add_sysprop_change_callback(changeCallback, 0);
const char* const traceFileName =
"/sys/kernel/debug/tracing/trace_marker";
sTraceFD = open(traceFileName, O_WRONLY);
if (sTraceFD == -1) {
ALOGE("error opening trace file: %s (%d)", strerror(errno), errno);
// sEnabledTags remains zero indicating that no tracing can occur
} else {
loadSystemProperty();
}
android_atomic_release_store(1, &sIsReady);
}
}
void Tracer::loadSystemProperty() {
char value[PROPERTY_VALUE_MAX];
property_get("debug.atrace.tags.enableflags", value, "0");
sEnabledTags = (strtoll(value, NULL, 0) & ATRACE_TAG_VALID_MASK)
| ATRACE_TAG_ALWAYS;
}
} // namespace andoid
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