platform_system_core/logd/LogBufferElement.h
Mark Salyzyn a2c022257c logd: record multiple duplicate messages as chatty
If a series of messages arrive from a single source with identical
message content payload, then suppress them and generate a chatty
report.  The checking is done on a per log id basis.

This alters the assumption that chatty messages are always at the
oldest entries, they now show up in the middle too.  To address this
change in behavior we print the first line, a chatty reference
which internally takes little space, then the last line in the series.

This does not conserve processing time in logd, and certainly has no
impact on the long path of formatting and submitting log messages from
from the source, but it may contribute to memory space and signal to
noise savings under heavy spammy loads.

Test: gTest liblog-unit-tests, logd-unit-tests & logcat-unit-tests
Bug: 33535908
Change-Id: I3160c36d4f4e2f8216f528605a1b3993173f4dec
2016-12-15 16:31:51 -08:00

92 lines
3.1 KiB
C++

/*
* Copyright (C) 2012-2014 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_BUFFER_ELEMENT_H__
#define _LOGD_LOG_BUFFER_ELEMENT_H__
#include <stdatomic.h>
#include <stdlib.h>
#include <sys/types.h>
#include <log/log.h>
#include <sysutils/SocketClient.h>
class LogBuffer;
#define EXPIRE_HOUR_THRESHOLD 24 // Only expire chatty UID logs to preserve
// non-chatty UIDs less than this age in hours
#define EXPIRE_THRESHOLD 10 // A smaller expire count is considered too
// chatty for the temporal expire messages
#define EXPIRE_RATELIMIT 10 // maximum rate in seconds to report expiration
class LogBufferElement {
friend LogBuffer;
// sized to match reality of incoming log packets
uint32_t mTag; // only valid for isBinary()
const uint32_t mUid;
const uint32_t mPid;
const uint32_t mTid;
const uint64_t mSequence;
log_time mRealTime;
char *mMsg;
union {
const uint16_t mMsgLen; // mMSg != NULL
uint16_t mDropped; // mMsg == NULL
};
const uint8_t mLogId;
static atomic_int_fast64_t sequence;
// assumption: mMsg == NULL
size_t populateDroppedMessage(char *&buffer,
LogBuffer *parent);
public:
LogBufferElement(log_id_t log_id, log_time realtime,
uid_t uid, pid_t pid, pid_t tid,
const char *msg, unsigned short len);
LogBufferElement(const LogBufferElement &elem);
virtual ~LogBufferElement();
bool isBinary(void) const {
return (mLogId == LOG_ID_EVENTS) || (mLogId == LOG_ID_SECURITY);
}
log_id_t getLogId() const { return static_cast<log_id_t>(mLogId); }
uid_t getUid(void) const { return mUid; }
pid_t getPid(void) const { return mPid; }
pid_t getTid(void) const { return mTid; }
uint32_t getTag() const { return mTag; }
unsigned short getDropped(void) const { return mMsg ? 0 : mDropped; }
unsigned short setDropped(unsigned short value) {
if (mMsg) {
delete [] mMsg;
mMsg = NULL;
}
return mDropped = value;
}
unsigned short getMsgLen() const { return mMsg ? mMsgLen : 0; }
const char* getMsg() const { return mMsg; }
uint64_t getSequence(void) const { return mSequence; }
static uint64_t getCurrentSequence(void) { return sequence.load(memory_order_relaxed); }
log_time getRealTime(void) const { return mRealTime; }
static const uint64_t FLUSH_ERROR;
uint64_t flushTo(SocketClient *writer, LogBuffer *parent, bool privileged);
};
#endif