android13/system/chre/platform/shared/log_buffer.cc

298 lines
9.8 KiB
C++

/*
* Copyright (C) 2020 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.
*/
#include "chre/platform/shared/log_buffer.h"
#include "chre/platform/assert.h"
#include "chre/util/lock_guard.h"
#include "include/chre/platform/shared/log_buffer.h"
#include <cstdarg>
#include <cstdio>
namespace chre {
LogBuffer::LogBuffer(LogBufferCallbackInterface *callback, void *buffer,
size_t bufferSize)
: mBufferData(static_cast<uint8_t *>(buffer)),
mBufferMaxSize(bufferSize),
mCallback(callback) {
CHRE_ASSERT(bufferSize >= kBufferMinSize);
}
void LogBuffer::handleLog(LogBufferLogLevel logLevel, uint32_t timestampMs,
const char *logFormat, ...) {
va_list args;
va_start(args, logFormat);
handleLogVa(logLevel, timestampMs, logFormat, args);
va_end(args);
}
void LogBuffer::handleLogVa(LogBufferLogLevel logLevel, uint32_t timestampMs,
const char *logFormat, va_list args) {
constexpr size_t maxLogLen = kLogMaxSize - kLogDataOffset;
char tempBuffer[maxLogLen];
int logLenSigned = vsnprintf(tempBuffer, maxLogLen, logFormat, args);
processLog(logLevel, timestampMs, tempBuffer, logLenSigned,
false /* encoded */);
}
void LogBuffer::handleEncodedLog(LogBufferLogLevel logLevel,
uint32_t timestampMs, const uint8_t *log,
size_t logSize) {
processLog(logLevel, timestampMs, log, logSize);
}
size_t LogBuffer::copyLogs(void *destination, size_t size,
size_t *numLogsDropped) {
LockGuard<Mutex> lock(mLock);
return copyLogsLocked(destination, size, numLogsDropped);
}
bool LogBuffer::logWouldCauseOverflow(size_t logSize) {
LockGuard<Mutex> lock(mLock);
return (mBufferDataSize + logSize + kLogDataOffset + 1 /* nullptr */ >
mBufferMaxSize);
}
void LogBuffer::transferTo(LogBuffer &buffer) {
LockGuard<Mutex> lockGuardOther(buffer.mLock);
size_t numLogsDropped;
size_t bytesCopied;
{
LockGuard<Mutex> lockGuardThis(mLock);
// The buffer being transferred to should be as big or bigger.
CHRE_ASSERT(buffer.mBufferMaxSize >= mBufferMaxSize);
buffer.resetLocked();
bytesCopied = copyLogsLocked(buffer.mBufferData, buffer.mBufferMaxSize,
&numLogsDropped);
resetLocked();
}
buffer.mBufferDataTailIndex = bytesCopied % buffer.mBufferMaxSize;
buffer.mBufferDataSize = bytesCopied;
buffer.mNumLogsDropped = numLogsDropped;
}
void LogBuffer::updateNotificationSetting(LogBufferNotificationSetting setting,
size_t thresholdBytes) {
LockGuard<Mutex> lock(mLock);
mNotificationSetting = setting;
mNotificationThresholdBytes = thresholdBytes;
}
void LogBuffer::reset() {
LockGuard<Mutex> lock(mLock);
resetLocked();
}
const uint8_t *LogBuffer::getBufferData() {
return mBufferData;
}
size_t LogBuffer::getBufferSize() {
LockGuard<Mutex> lockGuard(mLock);
return mBufferDataSize;
}
size_t LogBuffer::getNumLogsDropped() {
LockGuard<Mutex> lockGuard(mLock);
return mNumLogsDropped;
}
size_t LogBuffer::incrementAndModByBufferMaxSize(size_t originalVal,
size_t incrementBy) const {
return (originalVal + incrementBy) % mBufferMaxSize;
}
void LogBuffer::copyToBuffer(size_t size, const void *source) {
const uint8_t *sourceBytes = static_cast<const uint8_t *>(source);
if (mBufferDataTailIndex + size > mBufferMaxSize) {
size_t firstSize = mBufferMaxSize - mBufferDataTailIndex;
size_t secondSize = size - firstSize;
memcpy(&mBufferData[mBufferDataTailIndex], sourceBytes, firstSize);
memcpy(mBufferData, &sourceBytes[firstSize], secondSize);
} else {
memcpy(&mBufferData[mBufferDataTailIndex], sourceBytes, size);
}
mBufferDataSize += size;
mBufferDataTailIndex =
incrementAndModByBufferMaxSize(mBufferDataTailIndex, size);
}
void LogBuffer::copyFromBuffer(size_t size, void *destination) {
uint8_t *destinationBytes = static_cast<uint8_t *>(destination);
if (mBufferDataHeadIndex + size > mBufferMaxSize) {
size_t firstSize = mBufferMaxSize - mBufferDataHeadIndex;
size_t secondSize = size - firstSize;
memcpy(destinationBytes, &mBufferData[mBufferDataHeadIndex], firstSize);
memcpy(&destinationBytes[firstSize], mBufferData, secondSize);
} else {
memcpy(destinationBytes, &mBufferData[mBufferDataHeadIndex], size);
}
mBufferDataSize -= size;
mBufferDataHeadIndex =
incrementAndModByBufferMaxSize(mBufferDataHeadIndex, size);
}
size_t LogBuffer::copyLogsLocked(void *destination, size_t size,
size_t *numLogsDropped) {
size_t copySize = 0;
if (size != 0 && destination != nullptr && mBufferDataSize != 0) {
if (size >= mBufferDataSize) {
copySize = mBufferDataSize;
} else {
size_t logSize;
// There is guaranteed to be a null terminator within the max log length
// number of bytes so logStartIndex will not be maxBytes + 1
size_t logStartIndex = getNextLogIndex(mBufferDataHeadIndex, &logSize);
while (copySize + logSize <= size &&
copySize + logSize <= mBufferDataSize) {
copySize += logSize;
logStartIndex = getNextLogIndex(logStartIndex, &logSize);
}
}
copyFromBuffer(copySize, destination);
}
*numLogsDropped = mNumLogsDropped;
return copySize;
}
void LogBuffer::resetLocked() {
mBufferDataHeadIndex = 0;
mBufferDataTailIndex = 0;
mBufferDataSize = 0;
mNumLogsDropped = 0;
}
size_t LogBuffer::getNextLogIndex(size_t startingIndex, size_t *logSize) {
size_t logDataStartIndex =
incrementAndModByBufferMaxSize(startingIndex, kLogDataOffset);
size_t logDataSize = getLogDataLength(logDataStartIndex);
*logSize = kLogDataOffset + logDataSize;
return incrementAndModByBufferMaxSize(startingIndex, *logSize);
}
size_t LogBuffer::getLogDataLength(size_t startingIndex) {
size_t currentIndex = startingIndex;
constexpr size_t maxBytes = kLogMaxSize - kLogDataOffset;
size_t numBytes = maxBytes + 1;
for (size_t i = 0; i < maxBytes; i++) {
if (mBufferData[currentIndex] == '\0') {
// +1 to include the null terminator
numBytes = i + 1;
break;
}
currentIndex = incrementAndModByBufferMaxSize(currentIndex, 1);
}
return numBytes;
}
void LogBuffer::processLog(LogBufferLogLevel logLevel, uint32_t timestampMs,
const void *logBuffer, size_t size, bool encoded) {
if (size > 0) {
constexpr size_t kMaxLogLen = kLogMaxSize - kLogDataOffset;
auto logLen = static_cast<uint8_t>(size);
if (size >= kMaxLogLen) {
if (!encoded) {
// Leave space for nullptr to be copied on end
logLen = static_cast<uint8_t>(kMaxLogLen - 1);
} else {
// There is no way of decoding an encoded message if we truncate it, so
// we do the next best thing and try to log a generic failure message
// reusing the logbuffer for as much as we can. Note that we also need
// flip the encoding flag for proper decoding by the host log message
// parser.
constexpr char kGenericErrorMsg[] =
"Encoded log msg @t=%" PRIu32 "ms too large (%zub)";
std::snprintf(static_cast<char *>(const_cast<void *>(logBuffer)),
kMaxLogLen, kGenericErrorMsg, timestampMs, size);
encoded = false;
}
}
copyLogToBuffer(logLevel, timestampMs, logBuffer, logLen, encoded);
dispatch();
}
}
void LogBuffer::copyLogToBuffer(LogBufferLogLevel level, uint32_t timestampMs,
const void *logBuffer, uint8_t logLen,
bool encoded) {
LockGuard<Mutex> lockGuard(mLock);
discardExcessOldLogsLocked(encoded, logLen);
encodeAndCopyLogLocked(level, timestampMs, logBuffer, logLen, encoded);
}
void LogBuffer::discardExcessOldLogsLocked(bool encoded,
uint8_t currentLogLen) {
size_t totalLogSize =
kLogDataOffset + (encoded ? currentLogLen + 1 : currentLogLen);
while (mBufferDataSize + totalLogSize > mBufferMaxSize) {
mNumLogsDropped++;
size_t logSize;
mBufferDataHeadIndex = getNextLogIndex(mBufferDataHeadIndex, &logSize);
mBufferDataSize -= logSize;
}
}
void LogBuffer::encodeAndCopyLogLocked(LogBufferLogLevel level,
uint32_t timestampMs,
const void *logBuffer, uint8_t logLen,
bool encoded) {
uint8_t metadata =
(static_cast<uint8_t>(encoded) << 4) | static_cast<uint8_t>(level);
copyToBuffer(sizeof(uint8_t), &metadata);
copyToBuffer(sizeof(timestampMs), &timestampMs);
if (encoded) {
copyToBuffer(sizeof(uint8_t), &logLen);
}
copyToBuffer(logLen, logBuffer);
if (!encoded) {
copyToBuffer(1, reinterpret_cast<const void *>("\0"));
}
}
void LogBuffer::dispatch() {
if (mCallback != nullptr) {
switch (mNotificationSetting) {
case LogBufferNotificationSetting::ALWAYS: {
mCallback->onLogsReady();
break;
}
case LogBufferNotificationSetting::NEVER: {
break;
}
case LogBufferNotificationSetting::THRESHOLD: {
if (mBufferDataSize > mNotificationThresholdBytes) {
mCallback->onLogsReady();
}
break;
}
}
}
}
} // namespace chre