platform_system_core/logd/LogKlog.h
Mark Salyzyn b6bee33182 liblog: logd: support logd.timestamp = monotonic
if ro.logd.timestamp or persist.logd.timestamp are set to the value
monotonic then liblog writer, liblog printing and logd all switch to
recording/printing monotonic time rather than realtime. If reinit
detects a change for presist.logd.timestamp, correct the older entry
timestamps in place.

ToDo: A corner case condition where new log entries in monotonic time
      occur before logd reinit detects persist.logd.timestamp, there
      will be a few out-of-order entries, but with accurate
      timestamps. This problem does not happen for ro.logd.timestamp
      as it is set before logd starts.

NB: This offers a nano second time accuracy on all log entries
    that may be more suitable for merging with other system
    activities, such as systrace, that also use monotonic time. This
    feature is for debugging.

Bug: 23668800
Change-Id: Iee6dab7140061b1a6627254921411f61b01aa5c2
2015-11-03 15:15:51 -08:00

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/*
* Copyright (C) 2014 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.
*/
#ifndef _LOGD_LOG_KLOG_H__
#define _LOGD_LOG_KLOG_H__
#include <sysutils/SocketListener.h>
#include <log/log_read.h>
#include "LogReader.h"
char *log_strntok_r(char *s, size_t *len, char **saveptr, size_t *sublen);
class LogKlog : public SocketListener {
LogBuffer *logbuf;
LogReader *reader;
const log_time signature;
// Set once thread is started, separates KLOG_ACTION_READ_ALL
// and KLOG_ACTION_READ phases.
bool initialized;
// Used during each of the above phases to control logging.
bool enableLogging;
// set if we are also running auditd, to filter out audit reports from
// our copy of the kernel log
bool auditd;
static log_time correction;
public:
LogKlog(LogBuffer *buf, LogReader *reader, int fdWrite, int fdRead, bool auditd);
int log(const char *buf, size_t len);
void synchronize(const char *buf, size_t len);
bool isMonotonic() { return logbuf->isMonotonic(); }
static void convertMonotonicToReal(log_time &real) { real += correction; }
static void convertRealToMonotonic(log_time &real) { real -= correction; }
protected:
void sniffTime(log_time &now, const char **buf, size_t len, bool reverse);
pid_t sniffPid(const char *buf, size_t len);
void calculateCorrection(const log_time &monotonic,
const char *real_string, size_t len);
virtual bool onDataAvailable(SocketClient *cli);
};
#endif