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27f4261dfb0f98f87d8b9dad3d380d1d699dc736
epics-base/modules/libcom/src/fdmgr/fdManager.cpp

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/*************************************************************************\
* Copyright (c) 2002 The University of Chicago, as Operator of Argonne
* National Laboratory.
* Copyright (c) 2002 The Regents of the University of California, as
* Operator of Los Alamos National Laboratory.
* SPDX-License-Identifier: EPICS
* EPICS Base is distributed subject to a Software License Agreement found
* in file LICENSE that is included with this distribution.
\*************************************************************************/
//
// File descriptor management C++ class library
// (for multiplexing IO in a single threaded environment)
//
// Author Jeffrey O. Hill
// johill@lanl.gov
// 505 665 1831
//
// NOTES:
// 1) This library is not thread safe
//
#define instantiateRecourceLib
#include "epicsAssert.h"
#include "epicsThread.h"
#include "fdManager.h"
#include "locationException.h"
#if !defined(FDMGR_USE_POLL) && !defined(FDMGR_USE_SELECT)
#if defined(__linux__) || defined(darwin) || _WIN32_WINNT >= 0x600 || (defined(__rtems__) && !defined(RTEMS_LEGACY_STACK))
#define FDMGR_USE_POLL
#else
#define FDMGR_USE_SELECT
#endif
#endif
#ifdef FDMGR_USE_POLL
#include <vector>
#if defined(_WIN32)
#define poll WSAPoll
#else
#include <poll.h>
#endif
static const short PollEvents[] = { // must match fdRegType
POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR,
POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR,
POLLPRI};
#endif
#ifdef FDMGR_USE_SELECT
#include <algorithm>
#endif
struct fdManagerPrivate {
tsDLList < fdReg > regList;
tsDLList < fdReg > activeList;
resTable < fdReg, fdRegId > fdTbl;
const double sleepQuantum;
epics::auto_ptr <epicsTimerQueuePassive> pTimerQueue;
bool processInProg;
#ifdef FDMGR_USE_POLL
std::vector<struct pollfd> pollfds;
#endif
#ifdef FDMGR_USE_SELECT
fd_set fdSets[fdrNEnums];
SOCKET maxFD;
#endif
//
// Set to fdreg when in call back
// and nill otherwise
//
fdReg * pCBReg;
fdManager & owner;
explicit fdManagerPrivate(fdManager & owner);
void lazyInitTimerQueue();
};
fdManagerPrivate::fdManagerPrivate(fdManager & owner) :
sleepQuantum(epicsThreadSleepQuantum()),
processInProg(false),
pCBReg(0), owner(owner)
{}
inline void fdManagerPrivate::lazyInitTimerQueue ()
{
if (!pTimerQueue.get()) {
pTimerQueue.reset(&epicsTimerQueuePassive::create(owner));
}
}
epicsTimer & fdManager::createTimer()
{
priv->lazyInitTimerQueue();
return priv->pTimerQueue->createTimer();
}
fdManager fileDescriptorManager;
static const unsigned mSecPerSec = 1000u;
static const unsigned uSecPerSec = 1000u * mSecPerSec;
//
// fdManager::fdManager()
//
// hopefully its a reasonable guess that poll()/select() and epicsThreadSleep()
// will have the same sleep quantum
//
LIBCOM_API fdManager::fdManager () :
priv(new fdManagerPrivate(*this))
{
int status = osiSockAttach ();
assert (status);
#ifdef FDMGR_USE_SELECT
priv->maxFD = 0;
for ( size_t i = 0u; i < fdrNEnums; i++ ) {
FD_ZERO(&priv->fdSets[i]);
}
#endif
}
//
// fdManager::~fdManager()
//
LIBCOM_API fdManager::~fdManager()
{
fdReg *pReg;
while ((pReg = priv->regList.get())) {
pReg->state = fdReg::limbo;
pReg->destroy();
}
while ((pReg = priv->activeList.get())) {
pReg->state = fdReg::limbo;
pReg->destroy();
}
osiSockRelease();
}
//
// fdManager::process()
//
LIBCOM_API void fdManager::process (double delay)
{
priv->lazyInitTimerQueue ();
//
// no recursion
//
if (priv->processInProg)
return;
priv->processInProg = true;
//
// One shot at expired timers prior to going into
// poll/select. This allows zero delay timers to arm
// fd writes. We will never process the timer queue
// more than once here so that fd activity get serviced
// in a reasonable length of time.
//
double minDelay = priv->pTimerQueue->process(epicsTime::getCurrent());
if ( minDelay >= delay ) {
minDelay = delay;
}
#ifdef FDMGR_USE_POLL
priv->pollfds.clear();
#endif
int ioPending = 0;
tsDLIter<fdReg> iter = priv->regList.firstIter();
while ( iter.valid () ) {
++ioPending;
#ifdef FDMGR_USE_POLL
#if __cplusplus >= 201100L
priv->pollfds.emplace_back(pollfd{.fd = iter->getFD(), .events = PollEvents[iter->getType()]});
#else
struct pollfd pollfd;
pollfd.fd = iter->getFD();
pollfd.events = PollEvents[iter->getType()];
pollfd.revents = 0;
priv->pollfds.push_back(pollfd);
#endif
#endif
#ifdef FDMGR_USE_SELECT
FD_SET(iter->getFD(), &priv->fdSets[iter->getType()]);
#endif
++iter;
}
if ( ioPending ) {
#ifdef FDMGR_USE_POLL
if (minDelay * mSecPerSec > INT_MAX)
minDelay = INT_MAX / mSecPerSec;
int status = poll(&priv->pollfds.front(), // ancient C++ has no vector.data()
ioPending, static_cast<int>(minDelay * mSecPerSec));
int i = 0;
#endif
#ifdef FDMGR_USE_SELECT
struct timeval tv;
tv.tv_sec = static_cast<time_t> ( minDelay );
tv.tv_usec = static_cast<long> ( (minDelay-tv.tv_sec) * uSecPerSec );
int status = select(priv->maxFD,
&priv->fdSets[fdrRead],
&priv->fdSets[fdrWrite],
&priv->fdSets[fdrException], &tv);
#endif
priv->pTimerQueue->process(epicsTime::getCurrent());
if ( status > 0 ) {
//
// Look for activity
//
iter = priv->regList.firstIter ();
while ( iter.valid () && status > 0 ) {
tsDLIter < fdReg > tmp = iter;
tmp++;
#ifdef FDMGR_USE_POLL
// In a single threaded application, nothing should have
// changed the order of regList and pollfds by now.
// But just in case...
int isave = i;
while (priv->pollfds[i].fd != iter->getFD() ||
priv->pollfds[i].events != PollEvents[iter->getType()])
{
i++; // skip pollfd of removed items
if (i >= ioPending) { // skip unknown (inserted?) items
iter = tmp;
tmp++;
if (!iter.valid()) break;
i = isave;
}
}
if (i >= ioPending) break; // any unhandled item stays in regList for next time
if (priv->pollfds[i++].revents & PollEvents[iter->getType()]) {
#endif
#ifdef FDMGR_USE_SELECT
if (FD_ISSET(iter->getFD(), &priv->fdSets[iter->getType()])) {
FD_CLR(iter->getFD(), &priv->fdSets[iter->getType()]);
#endif
priv->regList.remove(*iter);
priv->activeList.add(*iter);
iter->state = fdReg::active;
status--;
}
iter = tmp;
}
//
// I am careful to prevent problems if they access the
// above list while in a "callBack()" routine
//
fdReg * pReg;
while ((pReg = priv->activeList.get())) {
pReg->state = fdReg::limbo;
//
// Tag current fdReg so that we
// can detect if it was deleted
// during the call back
//
priv->pCBReg = pReg;
pReg->callBack();
if (priv->pCBReg != NULL) {
//
// check only after we see that it is non-null so
// that we don't trigger bounds-checker dangling pointer
// error
//
assert(priv->pCBReg == pReg);
priv->pCBReg = NULL;
if (pReg->onceOnly) {
pReg->destroy();
}
else {
priv->regList.add(*pReg);
pReg->state = fdReg::pending;
}
}
}
}
else if ( status < 0 ) {
int errnoCpy = SOCKERRNO;
#ifdef FDMGR_USE_SELECT
// don't depend on flags being properly set if
// an error is returned from select
for ( size_t i = 0u; i < fdrNEnums; i++ ) {
FD_ZERO(&priv->fdSets[i]);
}
#endif
//
// print a message if it's an unexpected error
//
if ( errnoCpy != SOCK_EINTR ) {
char sockErrBuf[64];
epicsSocketConvertErrnoToString (
sockErrBuf, sizeof ( sockErrBuf ) );
errlogPrintf("fdManager: "
#ifdef FDMGR_USE_POLL
"poll()"
#endif
#ifdef FDMGR_USE_SELECT
"select()"
#endif
" failed because \"%s\"\n",
sockErrBuf);
}
}
}
else {
/*
* recover from subtle differences between
* windows sockets and UNIX sockets implementation
* of select()
*/
epicsThreadSleep(minDelay);
priv->pTimerQueue->process(epicsTime::getCurrent());
}
priv->processInProg = false;
}
//
// fdReg::destroy()
// (default destroy method)
//
void fdReg::destroy()
{
delete this;
}
//
// fdReg::~fdReg()
//
fdReg::~fdReg()
{
this->manager.removeReg(*this);
}
//
// fdReg::show()
//
void fdReg::show(unsigned level) const
{
printf ("fdReg at %p\n", (void *) this);
if (level>1u) {
printf ("\tstate = %d, onceOnly = %d\n",
this->state, this->onceOnly);
}
this->fdRegId::show(level);
}
//
// fdRegId::show()
//
void fdRegId::show ( unsigned level ) const
{
printf ( "fdRegId at %p\n",
static_cast <const void *> ( this ) );
if ( level > 1u ) {
printf ( "\tfd = %d, type = %d\n",
int(this->fd), this->type );
}
}
//
// fdManager::installReg ()
//
void fdManager::installReg (fdReg &reg)
{
#ifdef FDMGR_USE_SELECT
priv->maxFD = std::max(priv->maxFD, reg.getFD()+1);
#endif
// Most applications will find that it's important to push here to
// the front of the list so that transient writes get executed
// first allowing incoming read protocol to find that outgoing
// buffer space is newly available.
priv->regList.push(reg);
reg.state = fdReg::pending;
int status = priv->fdTbl.add(reg);
if ( status != 0 ) {
throwWithLocation ( fdInterestSubscriptionAlreadyExits () );
}
}
//
// fdManager::removeReg ()
//
void fdManager::removeReg (fdReg &regIn)
{
fdReg *pItemFound;
pItemFound = priv->fdTbl.remove(regIn);
if (pItemFound!=&regIn) {
errlogPrintf("fdManager::removeReg() bad fd registration object\n");
return;
}
//
// signal fdManager that the fdReg was deleted
// during the call back
//
if (priv->pCBReg == &regIn) {
priv->pCBReg = NULL;
}
switch (regIn.state) {
case fdReg::active:
priv->activeList.remove(regIn);
break;
case fdReg::pending:
priv->regList.remove(regIn);
break;
case fdReg::limbo:
break;
default:
//
// here if memory corrupted
//
assert(0);
}
regIn.state = fdReg::limbo;
#ifdef FDMGR_USE_SELECT
FD_CLR(regIn.getFD(), &priv->fdSets[regIn.getType()]);
#endif
}
//
// fdManager::reschedule ()
// NOOP - this only runs single threaded, and therefore they can only
// add a new timer from places that will always end up in a reschedule
//
void fdManager::reschedule ()
{
}
double fdManager::quantum ()
{
return priv->sleepQuantum;
}
//
// lookUpFD()
//
LIBCOM_API fdReg *fdManager::lookUpFD (const SOCKET fd, const fdRegType type)
{
if (fd<0) {
return NULL;
}
fdRegId id (fd,type);
return priv->fdTbl.lookup(id);
}
//
// fdReg::fdReg()
//
fdReg::fdReg (const SOCKET fdIn, const fdRegType typIn,
const bool onceOnlyIn, fdManager &managerIn) :
fdRegId (fdIn,typIn), state (limbo),
onceOnly (onceOnlyIn), manager (managerIn)
{
#ifdef FDMGR_USE_SELECT
if (!FD_IN_FDSET(fdIn)) {
errlogPrintf("%s: fd > FD_SETSIZE ignored\n",
__FILE__);
return;
}
#endif
this->manager.installReg (*this);
}
template class resTable<fdReg, fdRegId>;
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