363 lines
9.3 KiB
C++
363 lines
9.3 KiB
C++
/*************************************************************************\
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* Copyright (c) 2002 The University of Chicago, as Operator of Argonne
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* National Laboratory.
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* Copyright (c) 2002 The Regents of the University of California, as
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* Operator of Los Alamos National Laboratory.
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* EPICS BASE Versions 3.13.7
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* and higher are distributed subject to a Software License Agreement found
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* in file LICENSE that is included with this distribution.
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\*************************************************************************/
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//
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// File descriptor management C++ class library
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// (for multiplexing IO in a single threaded environment)
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//
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// Author Jeffrey O. Hill
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// johill@lanl.gov
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// 505 665 1831
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//
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// NOTES:
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// 1) This library is not thread safe
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//
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//
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// ANSI C
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//
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#include <errno.h>
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#include <string.h>
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#define instantiateRecourceLib
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#define epicsExportSharedSymbols
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#include "epicsAssert.h"
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#include "epicsThread.h"
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#include "tsMinMax.h"
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#include "fdManager.h"
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#include "locationException.h"
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epicsShareDef fdManager fileDescriptorManager;
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const unsigned mSecPerSec = 1000u;
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const unsigned uSecPerSec = 1000u * mSecPerSec;
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//
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// fdManager::fdManager()
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//
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// hopefully its a reasonable guess that select() and epicsThreadSleep()
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// will have the same sleep quantum
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//
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epicsShareFunc fdManager::fdManager () :
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sleepQuantum ( epicsThreadSleepQuantum () ),
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fdSetsPtr ( new fd_set [fdrNEnums] ),
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pTimerQueue ( 0 ), maxFD ( 0 ), processInProg ( false ),
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pCBReg ( 0 )
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{
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int status = osiSockAttach ();
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assert (status);
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for ( size_t i = 0u; i < fdrNEnums; i++ ) {
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FD_ZERO ( &fdSetsPtr[i] );
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}
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}
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//
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// fdManager::~fdManager()
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//
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epicsShareFunc fdManager::~fdManager()
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{
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fdReg *pReg;
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while ( (pReg = this->regList.get()) ) {
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pReg->state = fdReg::limbo;
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pReg->destroy();
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}
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while ( (pReg = this->activeList.get()) ) {
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pReg->state = fdReg::limbo;
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pReg->destroy();
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}
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delete this->pTimerQueue;
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delete [] this->fdSetsPtr;
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osiSockRelease();
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}
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//
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// fdManager::process()
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//
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epicsShareFunc void fdManager::process (double delay)
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{
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this->lazyInitTimerQueue ();
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//
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// no recursion
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//
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if (this->processInProg) {
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return;
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}
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this->processInProg = true;
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//
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// One shot at expired timers prior to going into
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// select. This allows zero delay timers to arm
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// fd writes. We will never process the timer queue
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// more than once here so that fd activity get serviced
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// in a reasonable length of time.
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//
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double minDelay = this->pTimerQueue->process(epicsTime::getCurrent());
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if ( minDelay >= delay ) {
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minDelay = delay;
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}
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bool ioPending = false;
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tsDLIter < fdReg > iter = this->regList.firstIter ();
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while ( iter.valid () ) {
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FD_SET(iter->getFD(), &this->fdSetsPtr[iter->getType()]);
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ioPending = true;
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++iter;
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}
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if ( ioPending ) {
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struct timeval tv;
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tv.tv_sec = static_cast<time_t> ( minDelay );
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tv.tv_usec = static_cast<long> ( (minDelay-tv.tv_sec) * uSecPerSec );
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fd_set * pReadSet = & this->fdSetsPtr[fdrRead];
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fd_set * pWriteSet = & this->fdSetsPtr[fdrWrite];
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fd_set * pExceptSet = & this->fdSetsPtr[fdrException];
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int status = select (this->maxFD, pReadSet, pWriteSet, pExceptSet, &tv);
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this->pTimerQueue->process(epicsTime::getCurrent());
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if ( status > 0 ) {
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//
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// Look for activity
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//
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iter=this->regList.firstIter ();
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while ( iter.valid () && status > 0 ) {
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tsDLIter < fdReg > tmp = iter;
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tmp++;
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if (FD_ISSET(iter->getFD(), &this->fdSetsPtr[iter->getType()])) {
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FD_CLR(iter->getFD(), &this->fdSetsPtr[iter->getType()]);
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this->regList.remove(*iter);
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this->activeList.add(*iter);
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iter->state = fdReg::active;
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status--;
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}
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iter = tmp;
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}
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//
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// I am careful to prevent problems if they access the
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// above list while in a "callBack()" routine
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//
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fdReg * pReg;
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while ( (pReg = this->activeList.get()) ) {
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pReg->state = fdReg::limbo;
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//
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// Tag current fdReg so that we
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// can detect if it was deleted
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// during the call back
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//
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this->pCBReg = pReg;
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pReg->callBack();
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if (this->pCBReg != NULL) {
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//
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// check only after we see that it is non-null so
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// that we dont trigger bounds-checker dangling pointer
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// error
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//
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assert (this->pCBReg==pReg);
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this->pCBReg = 0;
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if (pReg->onceOnly) {
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pReg->destroy();
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}
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else {
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this->regList.add(*pReg);
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pReg->state = fdReg::pending;
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}
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}
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}
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}
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else if ( status < 0 ) {
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int errnoCpy = SOCKERRNO;
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// dont depend on flags being properly set if
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// an error is retuned from select
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for ( size_t i = 0u; i < fdrNEnums; i++ ) {
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FD_ZERO ( &fdSetsPtr[i] );
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}
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//
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// print a message if its an unexpected error
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//
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if ( errnoCpy != SOCK_EINTR ) {
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char sockErrBuf[64];
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epicsSocketConvertErrnoToString (
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sockErrBuf, sizeof ( sockErrBuf ) );
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fprintf ( stderr,
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"fdManager: select failed because \"%s\"\n",
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sockErrBuf );
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}
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}
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}
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else {
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/*
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* recover from subtle differences between
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* windows sockets and UNIX sockets implementation
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* of select()
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*/
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epicsThreadSleep(minDelay);
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this->pTimerQueue->process(epicsTime::getCurrent());
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}
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this->processInProg = false;
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return;
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}
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//
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// fdReg::destroy()
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// (default destroy method)
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//
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epicsShareFunc void fdReg::destroy()
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{
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delete this;
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}
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//
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// fdReg::~fdReg()
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//
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epicsShareFunc fdReg::~fdReg()
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{
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this->manager.removeReg(*this);
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}
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//
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// fdReg::show()
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//
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epicsShareFunc void fdReg::show(unsigned level) const
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{
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printf ("fdReg at %p\n", (void *) this);
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if (level>1u) {
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printf ("\tstate = %d, onceOnly = %d\n",
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this->state, this->onceOnly);
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}
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this->fdRegId::show(level);
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}
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//
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// fdRegId::show()
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//
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void fdRegId::show ( unsigned level ) const
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{
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printf ( "fdRegId at %p\n",
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static_cast <const void *> ( this ) );
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if ( level > 1u ) {
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printf ( "\tfd = %d, type = %d\n",
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this->fd, this->type );
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}
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}
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//
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// fdManager::installReg ()
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//
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epicsShareFunc void fdManager::installReg (fdReg ®)
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{
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this->maxFD = tsMax ( this->maxFD, reg.getFD()+1 );
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// Most applications will find that its important to push here to
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// the front of the list so that transient writes get executed
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// first allowing incoming read protocol to find that outgoing
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// buffer space is newly available.
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this->regList.push ( reg );
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reg.state = fdReg::pending;
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int status = this->fdTbl.add ( reg );
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if ( status != 0 ) {
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throwWithLocation ( fdInterestSubscriptionAlreadyExits () );
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}
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}
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//
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// fdManager::removeReg ()
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//
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void fdManager::removeReg (fdReg ®In)
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{
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fdReg *pItemFound;
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pItemFound = this->fdTbl.remove (regIn);
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if (pItemFound!=®In) {
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fprintf(stderr,
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"fdManager::removeReg() bad fd registration object\n");
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return;
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}
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//
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// signal fdManager that the fdReg was deleted
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// during the call back
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//
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if (this->pCBReg == ®In) {
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this->pCBReg = 0;
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}
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switch (regIn.state) {
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case fdReg::active:
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this->activeList.remove (regIn);
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break;
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case fdReg::pending:
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this->regList.remove (regIn);
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break;
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case fdReg::limbo:
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break;
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default:
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//
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// here if memory corrupted
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//
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assert(0);
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}
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regIn.state = fdReg::limbo;
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FD_CLR(regIn.getFD(), &this->fdSetsPtr[regIn.getType()]);
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}
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//
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// fdManager::reschedule ()
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// NOOP - this only runs single threaded, and therefore they can only
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// add a new timer from places that will always end up in a reschedule
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//
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void fdManager::reschedule ()
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{
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}
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double fdManager::quantum ()
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{
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return this->sleepQuantum;
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}
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//
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// lookUpFD()
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//
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epicsShareFunc fdReg *fdManager::lookUpFD (const SOCKET fd, const fdRegType type)
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{
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if (fd<0) {
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return NULL;
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}
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fdRegId id (fd,type);
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return this->fdTbl.lookup(id);
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}
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//
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// fdReg::fdReg()
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//
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fdReg::fdReg (const SOCKET fdIn, const fdRegType typIn,
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const bool onceOnlyIn, fdManager &managerIn) :
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fdRegId (fdIn,typIn), state (limbo),
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onceOnly (onceOnlyIn), manager (managerIn)
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{
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if (!FD_IN_FDSET(fdIn)) {
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fprintf (stderr, "%s: fd > FD_SETSIZE ignored\n",
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__FILE__);
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return;
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}
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this->manager.installReg (*this);
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}
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template class resTable<fdReg, fdRegId>;
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