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/**
* @file llheartbeat.cpp
* @brief Class encapsulating logic for telling a watchdog that we live.
*
* $LicenseInfo:firstyear=2008&license=viewergpl$
*
* Copyright (c) 2008, Linden Research, Inc.
*
* Second Life Viewer Source Code
* The source code in this file ("Source Code") is provided by Linden Lab
* to you under the terms of the GNU General Public License, version 2.0
* ("GPL"), unless you have obtained a separate licensing agreement
* ("Other License"), formally executed by you and Linden Lab. Terms of
* the GPL can be found in doc/GPL-license.txt in this distribution, or
* online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
*
* There are special exceptions to the terms and conditions of the GPL as
* it is applied to this Source Code. View the full text of the exception
* in the file doc/FLOSS-exception.txt in this software distribution, or
* online at http://secondlifegrid.net/programs/open_source/licensing/flossexception
*
* By copying, modifying or distributing this software, you acknowledge
* that you have read and understood your obligations described above,
* and agree to abide by those obligations.
*
* ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
* WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
* COMPLETENESS OR PERFORMANCE.
* $/LicenseInfo$
*/
#include <errno.h>
#include <signal.h>
#include "linden_common.h"
#include "llapp.h"
#include "llheartbeat.h"
LLHeartbeat::LLHeartbeat(F32 secs_between_heartbeat,
F32 aggressive_heartbeat_panic_secs,
F32 aggressive_heartbeat_max_blocking_secs)
: mSecsBetweenHeartbeat(secs_between_heartbeat),
mAggressiveHeartbeatPanicSecs(aggressive_heartbeat_panic_secs),
mAggressiveHeartbeatMaxBlockingSecs(aggressive_heartbeat_max_blocking_secs),
mSuppressed(false)
{
mBeatTimer.reset();
mBeatTimer.setTimerExpirySec(mSecsBetweenHeartbeat);
mPanicTimer.reset();
mPanicTimer.setTimerExpirySec(mAggressiveHeartbeatPanicSecs);
}
LLHeartbeat::~LLHeartbeat()
{
// do nothing.
}
void
LLHeartbeat::setSuppressed(bool is_suppressed)
{
mSuppressed = is_suppressed;
}
// returns 0 on success, -1 on permanent failure, 1 on temporary failure
int
LLHeartbeat::rawSend()
{
#if LL_WINDOWS
return 0; // Pretend we succeeded.
#else
if (mSuppressed)
return 0; // Pretend we succeeded.
int result;
#ifndef LL_DARWIN
union sigval dummy;
result = sigqueue(getppid(), LL_HEARTBEAT_SIGNAL, dummy);
#else
result = kill(getppid(), LL_HEARTBEAT_SIGNAL);
#endif
if (result == 0)
return 0; // success
int err = errno;
if (err == EAGAIN)
return 1; // failed to queue, try again
return -1; // other failure.
#endif
}
int
LLHeartbeat::rawSendWithTimeout(F32 timeout_sec)
{
int result = 0;
// Spin tightly until our heartbeat is digested by the watchdog
// or we time-out. We don't really want to sleep because our
// wake-up time might be undesirably synchronised to a hidden
// clock by the system's scheduler.
mTimeoutTimer.reset();
mTimeoutTimer.setTimerExpirySec(timeout_sec);
do {
result = rawSend();
//llinfos << " HEARTSENDc=" << result << llendl;
} while (result==1 && !mTimeoutTimer.hasExpired());
return result;
}
bool
LLHeartbeat::send(F32 timeout_sec)
{
bool total_success = false;
int result = 1;
if (timeout_sec > 0.f) {
// force a spin until success or timeout
result = rawSendWithTimeout(timeout_sec);
} else {
if (mBeatTimer.hasExpired()) {
// zero-timeout; we don't care too much whether our
// heartbeat was digested.
result = rawSend();
//llinfos << " HEARTSENDb=" << result << llendl;
}
}
if (result == -1) {
// big failure.
} else if (result == 0) {
total_success = true;
} else {
// need to retry at some point
}
if (total_success) {
mBeatTimer.reset();
mBeatTimer.setTimerExpirySec(mSecsBetweenHeartbeat);
// reset the time until we start panicking about lost
// heartbeats again.
mPanicTimer.reset();
mPanicTimer.setTimerExpirySec(mAggressiveHeartbeatPanicSecs);
} else {
// leave mBeatTimer as expired so we'll lazily poke the
// watchdog again next time through.
}
if (mPanicTimer.hasExpired()) {
// It's been ages since we successfully had a heartbeat
// digested by the watchdog. Sit here and spin a while
// in the hope that we can force it through.
llwarns << "Unable to deliver heartbeat to launcher for " << mPanicTimer.getElapsedTimeF32() << " seconds. Going to try very hard for up to " << mAggressiveHeartbeatMaxBlockingSecs << " seconds." << llendl;
result = rawSendWithTimeout(mAggressiveHeartbeatMaxBlockingSecs);
if (result == 0) {
total_success = true;
} else {
// we couldn't even force it through. That's bad,
// but we'll try again in a while.
llwarns << "Could not deliver heartbeat to launcher even after trying very hard for " << mAggressiveHeartbeatMaxBlockingSecs << " seconds." << llendl;
}
// in any case, reset the panic timer.
mPanicTimer.reset();
mPanicTimer.setTimerExpirySec(mAggressiveHeartbeatPanicSecs);
}
return total_success;
}
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