555f89d8df
Every IBinder object can accept a new transaction to tell it that it might want to reload system properties, and in the process anyone can register a callback to be executed when this happens. Use this to reload the trace property. This is very much ONLY for debugging. Change-Id: I55c67c46f8f3fa9073bef0dfaab4577ed1d47eb4
66 lines
1.9 KiB
C++
66 lines
1.9 KiB
C++
/*
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* Copyright (C) 2012 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#define LOG_TAG "Trace"
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#include <cutils/properties.h>
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#include <utils/Log.h>
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#include <utils/Trace.h>
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#include <utils/misc.h>
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namespace android {
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volatile int32_t Tracer::sIsReady = 0;
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int Tracer::sTraceFD = -1;
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uint64_t Tracer::sEnabledTags = 0;
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Mutex Tracer::sMutex;
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void Tracer::changeCallback() {
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Mutex::Autolock lock(sMutex);
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if (sIsReady && sTraceFD >= 0) {
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loadSystemProperty();
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}
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}
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void Tracer::init() {
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Mutex::Autolock lock(sMutex);
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if (!sIsReady) {
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add_sysprop_change_callback(changeCallback, 0);
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const char* const traceFileName =
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"/sys/kernel/debug/tracing/trace_marker";
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sTraceFD = open(traceFileName, O_WRONLY);
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if (sTraceFD == -1) {
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ALOGE("error opening trace file: %s (%d)", strerror(errno), errno);
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// sEnabledTags remains zero indicating that no tracing can occur
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} else {
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loadSystemProperty();
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}
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android_atomic_release_store(1, &sIsReady);
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}
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}
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void Tracer::loadSystemProperty() {
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char value[PROPERTY_VALUE_MAX];
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property_get("debug.atrace.tags.enableflags", value, "0");
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sEnabledTags = (strtoll(value, NULL, 0) & ATRACE_TAG_VALID_MASK)
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| ATRACE_TAG_ALWAYS;
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}
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} // namespace andoid
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