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em.cpp
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em.cpp
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/*****************************************************************************
$Id$
File: em.cpp
Date: 06Apr06
Copyright (C) 2006-07 by Francis Cianfrocca. All Rights Reserved.
Gmail: blackhedd
This program is free software; you can redistribute it and/or modify
it under the terms of either: 1) the GNU General Public License
as published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version; or 2) Ruby's License.
See the file COPYING for complete licensing information.
*****************************************************************************/
// THIS ENTIRE FILE WILL EVENTUALLY BE FOR UNIX BUILDS ONLY.
//#ifdef OS_UNIX
#include "project.h"
/* The numer of max outstanding timers was once a const enum defined in em.h.
* Now we define it here so that users can change its value if necessary.
*/
static unsigned int MaxOutstandingTimers = 100000;
/* Internal helper to convert strings to internet addresses. IPv6-aware.
* Not reentrant or threadsafe, optimized for speed.
*/
static struct sockaddr *name2address (const char *server, int port, int *family, int *bind_size);
/***************************************
STATIC EventMachine_t::GetMaxTimerCount
***************************************/
int EventMachine_t::GetMaxTimerCount()
{
return MaxOutstandingTimers;
}
/***************************************
STATIC EventMachine_t::SetMaxTimerCount
***************************************/
void EventMachine_t::SetMaxTimerCount (int count)
{
/* Allow a user to increase the maximum number of outstanding timers.
* If this gets "too high" (a metric that is of course platform dependent),
* bad things will happen like performance problems and possible overuse
* of memory.
* The actual timer mechanism is very efficient so it's hard to know what
* the practical max, but 100,000 shouldn't be too problematical.
*/
if (count < 100)
count = 100;
MaxOutstandingTimers = count;
}
/******************************
EventMachine_t::EventMachine_t
******************************/
EventMachine_t::EventMachine_t (EMCallback event_callback):
HeartbeatInterval(2000000),
EventCallback (event_callback),
NextHeartbeatTime (0),
LoopBreakerReader (-1),
LoopBreakerWriter (-1),
NumCloseScheduled (0),
bTerminateSignalReceived (false),
bEpoll (false),
epfd (-1),
bKqueue (false),
kqfd (-1),
inotify (NULL)
{
// Default time-slice is just smaller than one hundred mills.
Quantum.tv_sec = 0;
Quantum.tv_usec = 90000;
// Make sure the current loop time is sane, in case we do any initializations of
// objects before we start running.
_UpdateTime();
/* We initialize the network library here (only on Windows of course)
* and initialize "loop breakers." Our destructor also does some network-level
* cleanup. There's thus an implicit assumption that any given instance of EventMachine_t
* will only call ::Run once. Is that a good assumption? Should we move some of these
* inits and de-inits into ::Run?
*/
#ifdef OS_WIN32
WSADATA w;
WSAStartup (MAKEWORD (1, 1), &w);
#endif
_InitializeLoopBreaker();
}
/*******************************
EventMachine_t::~EventMachine_t
*******************************/
EventMachine_t::~EventMachine_t()
{
// Run down descriptors
size_t i;
for (i = 0; i < NewDescriptors.size(); i++)
delete NewDescriptors[i];
for (i = 0; i < Descriptors.size(); i++)
delete Descriptors[i];
close (LoopBreakerReader);
close (LoopBreakerWriter);
// Remove any file watch descriptors
while(!Files.empty()) {
map<int, Bindable_t*>::iterator f = Files.begin();
UnwatchFile (f->first);
}
if (epfd != -1)
close (epfd);
if (kqfd != -1)
close (kqfd);
}
/*************************
EventMachine_t::_UseEpoll
*************************/
void EventMachine_t::_UseEpoll()
{
/* Temporary.
* Use an internal flag to switch in epoll-based functionality until we determine
* how it should be integrated properly and the extent of the required changes.
* A permanent solution needs to allow the integration of additional technologies,
* like kqueue and Solaris's events.
*/
#ifdef HAVE_EPOLL
bEpoll = true;
#endif
}
/**************************
EventMachine_t::_UseKqueue
**************************/
void EventMachine_t::_UseKqueue()
{
/* Temporary.
* See comments under _UseEpoll.
*/
#ifdef HAVE_KQUEUE
bKqueue = true;
#endif
}
/****************************
EventMachine_t::ScheduleHalt
****************************/
void EventMachine_t::ScheduleHalt()
{
/* This is how we stop the machine.
* This can be called by clients. Signal handlers will probably
* set the global flag.
* For now this means there can only be one EventMachine ever running at a time.
*
* IMPORTANT: keep this light, fast, and async-safe. Don't do anything frisky in here,
* because it may be called from signal handlers invoked from code that we don't
* control. At this writing (20Sep06), EM does NOT install any signal handlers of
* its own.
*
* We need a FAQ. And one of the questions is: how do I stop EM when Ctrl-C happens?
* The answer is to call evma_stop_machine, which calls here, from a SIGINT handler.
*/
bTerminateSignalReceived = true;
}
/*******************************
EventMachine_t::SetTimerQuantum
*******************************/
void EventMachine_t::SetTimerQuantum (int interval)
{
/* We get a timer-quantum expressed in milliseconds.
*/
if ((interval < 5) || (interval > 5*60*1000))
throw std::runtime_error ("invalid timer-quantum");
Quantum.tv_sec = interval / 1000;
Quantum.tv_usec = (interval % 1000) * 1000;
}
/*************************************
(STATIC) EventMachine_t::SetuidString
*************************************/
void EventMachine_t::SetuidString (const char *username)
{
/* This method takes a caller-supplied username and tries to setuid
* to that user. There is no meaningful implementation (and no error)
* on Windows. On Unix, a failure to setuid the caller-supplied string
* causes a fatal abort, because presumably the program is calling here
* in order to fulfill a security requirement. If we fail silently,
* the user may continue to run with too much privilege.
*
* TODO, we need to decide on and document a way of generating C++ level errors
* that can be wrapped in documented Ruby exceptions, so users can catch
* and handle them. And distinguish it from errors that we WON'T let the Ruby
* user catch (like security-violations and resource-overallocation).
* A setuid failure here would be in the latter category.
*/
#ifdef OS_UNIX
if (!username || !*username)
throw std::runtime_error ("setuid_string failed: no username specified");
struct passwd *p = getpwnam (username);
if (!p)
throw std::runtime_error ("setuid_string failed: unknown username");
if (setuid (p->pw_uid) != 0)
throw std::runtime_error ("setuid_string failed: no setuid");
// Success.
#endif
}
/****************************************
(STATIC) EventMachine_t::SetRlimitNofile
****************************************/
int EventMachine_t::SetRlimitNofile (int nofiles)
{
#ifdef OS_UNIX
struct rlimit rlim;
getrlimit (RLIMIT_NOFILE, &rlim);
if (nofiles >= 0) {
rlim.rlim_cur = nofiles;
if ((unsigned int)nofiles > rlim.rlim_max)
rlim.rlim_max = nofiles;
setrlimit (RLIMIT_NOFILE, &rlim);
// ignore the error return, for now at least.
// TODO, emit an error message someday when we have proper debug levels.
}
getrlimit (RLIMIT_NOFILE, &rlim);
return rlim.rlim_cur;
#endif
#ifdef OS_WIN32
// No meaningful implementation on Windows.
return 0;
#endif
}
/*********************************
EventMachine_t::SignalLoopBreaker
*********************************/
void EventMachine_t::SignalLoopBreaker()
{
#ifdef OS_UNIX
write (LoopBreakerWriter, "", 1);
#endif
#ifdef OS_WIN32
sendto (LoopBreakerReader, "", 0, 0, (struct sockaddr*)&(LoopBreakerTarget), sizeof(LoopBreakerTarget));
#endif
}
/**************************************
EventMachine_t::_InitializeLoopBreaker
**************************************/
void EventMachine_t::_InitializeLoopBreaker()
{
/* A "loop-breaker" is a socket-descriptor that we can write to in order
* to break the main select loop. Primarily useful for things running on
* threads other than the main EM thread, so they can trigger processing
* of events that arise exogenously to the EM.
* Keep the loop-breaker pipe out of the main descriptor set, otherwise
* its events will get passed on to user code.
*/
#ifdef OS_UNIX
int fd[2];
if (pipe (fd))
throw std::runtime_error (strerror(errno));
LoopBreakerWriter = fd[1];
LoopBreakerReader = fd[0];
/* 16Jan11: Make sure the pipe is non-blocking, so more than 65k loopbreaks
* in one tick do not fill up the pipe and block the process on write() */
SetSocketNonblocking (LoopBreakerWriter);
#endif
#ifdef OS_WIN32
int sd = socket (AF_INET, SOCK_DGRAM, 0);
if (sd == INVALID_SOCKET)
throw std::runtime_error ("no loop breaker socket");
SetSocketNonblocking (sd);
memset (&LoopBreakerTarget, 0, sizeof(LoopBreakerTarget));
LoopBreakerTarget.sin_family = AF_INET;
LoopBreakerTarget.sin_addr.s_addr = inet_addr ("127.0.0.1");
srand ((int)time(NULL));
int i;
for (i=0; i < 100; i++) {
int r = (rand() % 10000) + 20000;
LoopBreakerTarget.sin_port = htons (r);
if (bind (sd, (struct sockaddr*)&LoopBreakerTarget, sizeof(LoopBreakerTarget)) == 0)
break;
}
if (i == 100)
throw std::runtime_error ("no loop breaker");
LoopBreakerReader = sd;
#endif
}
/***************************
EventMachine_t::_UpdateTime
***************************/
void EventMachine_t::_UpdateTime()
{
MyCurrentLoopTime = GetRealTime();
}
/***************************
EventMachine_t::GetRealTime
***************************/
uint64_t EventMachine_t::GetRealTime()
{
uint64_t current_time;
#if defined(OS_UNIX)
struct timeval tv;
gettimeofday (&tv, NULL);
current_time = (((uint64_t)(tv.tv_sec)) * 1000000LL) + ((uint64_t)(tv.tv_usec));
#elif defined(OS_WIN32)
unsigned tick = GetTickCount();
if (tick < LastTickCount)
TickCountTickover += 1;
LastTickCount = tick;
current_time = ((uint64_t)TickCountTickover << 32) + (uint64_t)tick;
current_time *= 1000; // convert to microseconds
#else
current_time = (uint64_t)time(NULL) * 1000000LL;
#endif
return current_time;
}
/***********************************
EventMachine_t::_DispatchHeartbeats
***********************************/
void EventMachine_t::_DispatchHeartbeats()
{
// Store the first processed heartbeat descriptor and bail out if
// we see it again. This fixes an infinite loop in case the system time
// is changed out from underneath MyCurrentLoopTime.
const EventableDescriptor *head = NULL;
while (true) {
multimap<uint64_t,EventableDescriptor*>::iterator i = Heartbeats.begin();
if (i == Heartbeats.end())
break;
if (i->first > MyCurrentLoopTime)
break;
EventableDescriptor *ed = i->second;
if (ed == head)
break;
ed->Heartbeat();
QueueHeartbeat(ed);
if (head == NULL)
head = ed;
}
}
/******************************
EventMachine_t::QueueHeartbeat
******************************/
void EventMachine_t::QueueHeartbeat(EventableDescriptor *ed)
{
uint64_t heartbeat = ed->GetNextHeartbeat();
if (heartbeat) {
#ifndef HAVE_MAKE_PAIR
Heartbeats.insert (multimap<uint64_t,EventableDescriptor*>::value_type (heartbeat, ed));
#else
Heartbeats.insert (make_pair (heartbeat, ed));
#endif
}
}
/******************************
EventMachine_t::ClearHeartbeat
******************************/
void EventMachine_t::ClearHeartbeat(uint64_t key, EventableDescriptor* ed)
{
multimap<uint64_t,EventableDescriptor*>::iterator it;
pair<multimap<uint64_t,EventableDescriptor*>::iterator,multimap<uint64_t,EventableDescriptor*>::iterator> ret;
ret = Heartbeats.equal_range (key);
for (it = ret.first; it != ret.second; ++it) {
if (it->second == ed) {
Heartbeats.erase (it);
break;
}
}
}
/*******************
EventMachine_t::Run
*******************/
void EventMachine_t::Run()
{
#ifdef HAVE_EPOLL
if (bEpoll) {
epfd = epoll_create (MaxEpollDescriptors);
if (epfd == -1) {
char buf[200];
snprintf (buf, sizeof(buf)-1, "unable to create epoll descriptor: %s", strerror(errno));
throw std::runtime_error (buf);
}
int cloexec = fcntl (epfd, F_GETFD, 0);
assert (cloexec >= 0);
cloexec |= FD_CLOEXEC;
fcntl (epfd, F_SETFD, cloexec);
assert (LoopBreakerReader >= 0);
LoopbreakDescriptor *ld = new LoopbreakDescriptor (LoopBreakerReader, this);
assert (ld);
Add (ld);
}
#endif
#ifdef HAVE_KQUEUE
if (bKqueue) {
kqfd = kqueue();
if (kqfd == -1) {
char buf[200];
snprintf (buf, sizeof(buf)-1, "unable to create kqueue descriptor: %s", strerror(errno));
throw std::runtime_error (buf);
}
// cloexec not needed. By definition, kqueues are not carried across forks.
assert (LoopBreakerReader >= 0);
LoopbreakDescriptor *ld = new LoopbreakDescriptor (LoopBreakerReader, this);
assert (ld);
Add (ld);
}
#endif
while (true) {
_UpdateTime();
_RunTimers();
/* _Add must precede _Modify because the same descriptor might
* be on both lists during the same pass through the machine,
* and to modify a descriptor before adding it would fail.
*/
_AddNewDescriptors();
_ModifyDescriptors();
_RunOnce();
if (bTerminateSignalReceived)
break;
}
}
/************************
EventMachine_t::_RunOnce
************************/
void EventMachine_t::_RunOnce()
{
if (bEpoll)
_RunEpollOnce();
else if (bKqueue)
_RunKqueueOnce();
else
_RunSelectOnce();
_DispatchHeartbeats();
_CleanupSockets();
}
/*****************************
EventMachine_t::_RunEpollOnce
*****************************/
void EventMachine_t::_RunEpollOnce()
{
#ifdef HAVE_EPOLL
assert (epfd != -1);
int s;
timeval tv = _TimeTilNextEvent();
#ifdef BUILD_FOR_RUBY
int ret = 0;
#ifdef HAVE_RB_WAIT_FOR_SINGLE_FD
if ((ret = rb_wait_for_single_fd(epfd, RB_WAITFD_IN|RB_WAITFD_PRI, &tv)) < 1) {
#else
fd_set fdreads;
FD_ZERO(&fdreads);
FD_SET(epfd, &fdreads);
if ((ret = rb_thread_select(epfd + 1, &fdreads, NULL, NULL, &tv)) < 1) {
#endif
if (ret == -1) {
assert(errno != EINVAL);
assert(errno != EBADF);
}
return;
}
TRAP_BEG;
s = epoll_wait (epfd, epoll_events, MaxEvents, 0);
TRAP_END;
#else
int duration = 0;
duration = duration + (tv.tv_sec * 1000);
duration = duration + (tv.tv_usec / 1000);
s = epoll_wait (epfd, epoll_events, MaxEvents, duration);
#endif
if (s > 0) {
for (int i=0; i < s; i++) {
EventableDescriptor *ed = (EventableDescriptor*) epoll_events[i].data.ptr;
if (ed->IsWatchOnly() && ed->GetSocket() == INVALID_SOCKET)
continue;
assert(ed->GetSocket() != INVALID_SOCKET);
if (epoll_events[i].events & EPOLLIN)
ed->Read();
if (epoll_events[i].events & EPOLLOUT)
ed->Write();
if (epoll_events[i].events & (EPOLLERR | EPOLLHUP))
ed->HandleError();
}
}
else if (s < 0) {
// epoll_wait can fail on error in a handful of ways.
// If this happens, then wait for a little while to avoid busy-looping.
// If the error was EINTR, we probably caught SIGCHLD or something,
// so keep the wait short.
timeval tv = {0, ((errno == EINTR) ? 5 : 50) * 1000};
EmSelect (0, NULL, NULL, NULL, &tv);
}
#else
throw std::runtime_error ("epoll is not implemented on this platform");
#endif
}
/******************************
EventMachine_t::_RunKqueueOnce
******************************/
void EventMachine_t::_RunKqueueOnce()
{
#ifdef HAVE_KQUEUE
assert (kqfd != -1);
int k;
timeval tv = _TimeTilNextEvent();
struct timespec ts;
ts.tv_sec = tv.tv_sec;
ts.tv_nsec = tv.tv_usec * 1000;
#ifdef BUILD_FOR_RUBY
int ret = 0;
#ifdef HAVE_RB_WAIT_FOR_SINGLE_FD
if ((ret = rb_wait_for_single_fd(kqfd, RB_WAITFD_IN|RB_WAITFD_PRI, &tv)) < 1) {
#else
fd_set fdreads;
FD_ZERO(&fdreads);
FD_SET(kqfd, &fdreads);
if ((ret = rb_thread_select(kqfd + 1, &fdreads, NULL, NULL, &tv)) < 1) {
#endif
if (ret == -1) {
assert(errno != EINVAL);
assert(errno != EBADF);
}
return;
}
TRAP_BEG;
ts.tv_sec = ts.tv_nsec = 0;
k = kevent (kqfd, NULL, 0, Karray, MaxEvents, &ts);
TRAP_END;
#else
k = kevent (kqfd, NULL, 0, Karray, MaxEvents, &ts);
#endif
struct kevent *ke = Karray;
while (k > 0) {
switch (ke->filter)
{
case EVFILT_VNODE:
_HandleKqueueFileEvent (ke);
break;
case EVFILT_PROC:
_HandleKqueuePidEvent (ke);
break;
case EVFILT_READ:
case EVFILT_WRITE:
EventableDescriptor *ed = (EventableDescriptor*) (ke->udata);
assert (ed);
if (ed->IsWatchOnly() && ed->GetSocket() == INVALID_SOCKET)
break;
if (ke->filter == EVFILT_READ)
ed->Read();
else if (ke->filter == EVFILT_WRITE)
ed->Write();
else
cerr << "Discarding unknown kqueue event " << ke->filter << endl;
break;
}
--k;
++ke;
}
// TODO, replace this with rb_thread_blocking_region for 1.9 builds.
#ifdef BUILD_FOR_RUBY
if (!rb_thread_alone()) {
rb_thread_schedule();
}
#endif
#else
throw std::runtime_error ("kqueue is not implemented on this platform");
#endif
}
/*********************************
EventMachine_t::_TimeTilNextEvent
*********************************/
timeval EventMachine_t::_TimeTilNextEvent()
{
// 29jul11: Changed calculation base from MyCurrentLoopTime to the
// real time. As MyCurrentLoopTime is set at the beginning of an
// iteration and this calculation is done at the end, evenmachine
// will potentially oversleep by the amount of time the iteration
// took to execute.
uint64_t next_event = 0;
uint64_t current_time = GetRealTime();
if (!Heartbeats.empty()) {
multimap<uint64_t,EventableDescriptor*>::iterator heartbeats = Heartbeats.begin();
next_event = heartbeats->first;
}
if (!Timers.empty()) {
multimap<uint64_t,Timer_t>::iterator timers = Timers.begin();
if (next_event == 0 || timers->first < next_event)
next_event = timers->first;
}
if (!NewDescriptors.empty() || !ModifiedDescriptors.empty()) {
next_event = current_time;
}
timeval tv;
if (NumCloseScheduled > 0 || bTerminateSignalReceived) {
tv.tv_sec = tv.tv_usec = 0;
} else if (next_event == 0) {
tv = Quantum;
} else {
if (next_event > current_time) {
uint64_t duration = next_event - current_time;
tv.tv_sec = duration / 1000000;
tv.tv_usec = duration % 1000000;
} else {
tv.tv_sec = tv.tv_usec = 0;
}
}
return tv;
}
/*******************************
EventMachine_t::_CleanupSockets
*******************************/
void EventMachine_t::_CleanupSockets()
{
// TODO, rip this out and only delete the descriptors we know have died,
// rather than traversing the whole list.
// Modified 05Jan08 per suggestions by Chris Heath. It's possible that
// an EventableDescriptor will have a descriptor value of -1. That will
// happen if EventableDescriptor::Close was called on it. In that case,
// don't call epoll_ctl to remove the socket's filters from the epoll set.
// According to the epoll docs, this happens automatically when the
// descriptor is closed anyway. This is different from the case where
// the socket has already been closed but the descriptor in the ED object
// hasn't yet been set to INVALID_SOCKET.
// In kqueue, closing a descriptor automatically removes its event filters.
int i, j;
int nSockets = Descriptors.size();
for (i=0, j=0; i < nSockets; i++) {
EventableDescriptor *ed = Descriptors[i];
assert (ed);
if (ed->ShouldDelete()) {
#ifdef HAVE_EPOLL
if (bEpoll) {
assert (epfd != -1);
if (ed->GetSocket() != INVALID_SOCKET) {
int e = epoll_ctl (epfd, EPOLL_CTL_DEL, ed->GetSocket(), ed->GetEpollEvent());
// ENOENT or EBADF are not errors because the socket may be already closed when we get here.
if (e && (errno != ENOENT) && (errno != EBADF) && (errno != EPERM)) {
char buf [200];
snprintf (buf, sizeof(buf)-1, "unable to delete epoll event: %s", strerror(errno));
throw std::runtime_error (buf);
}
}
ModifiedDescriptors.erase(ed);
}
#endif
delete ed;
}
else
Descriptors [j++] = ed;
}
while ((size_t)j < Descriptors.size())
Descriptors.pop_back();
}
/*********************************
EventMachine_t::_ModifyEpollEvent
*********************************/
void EventMachine_t::_ModifyEpollEvent (EventableDescriptor *ed)
{
#ifdef HAVE_EPOLL
if (bEpoll) {
assert (epfd != -1);
assert (ed);
assert (ed->GetSocket() != INVALID_SOCKET);
int e = epoll_ctl (epfd, EPOLL_CTL_MOD, ed->GetSocket(), ed->GetEpollEvent());
if (e) {
char buf [200];
snprintf (buf, sizeof(buf)-1, "unable to modify epoll event: %s", strerror(errno));
throw std::runtime_error (buf);
}
}
#endif
}
/**************************
SelectData_t::SelectData_t
**************************/
SelectData_t::SelectData_t()
{
maxsocket = 0;
FD_ZERO (&fdreads);
FD_ZERO (&fdwrites);
FD_ZERO (&fderrors);
}
#ifdef BUILD_FOR_RUBY
/*****************
_SelectDataSelect
*****************/
#if defined(HAVE_TBR) || defined(HAVE_RB_THREAD_CALL_WITHOUT_GVL)
static VALUE _SelectDataSelect (void *v)
{
SelectData_t *sd = (SelectData_t*)v;
sd->nSockets = select (sd->maxsocket+1, &(sd->fdreads), &(sd->fdwrites), &(sd->fderrors), &(sd->tv));
return Qnil;
}
#endif
/*********************
SelectData_t::_Select
*********************/
int SelectData_t::_Select()
{
#if defined(HAVE_RB_THREAD_CALL_WITHOUT_GVL)
rb_thread_call_without_gvl ((void *(*)(void *))_SelectDataSelect, (void*)this, RUBY_UBF_IO, 0);
return nSockets;
#elif defined(HAVE_TBR)
rb_thread_blocking_region (_SelectDataSelect, (void*)this, RUBY_UBF_IO, 0);
return nSockets;
#else
return EmSelect (maxsocket+1, &fdreads, &fdwrites, &fderrors, &tv);
#endif
}
#endif
/******************************
EventMachine_t::_RunSelectOnce
******************************/
void EventMachine_t::_RunSelectOnce()
{
// Crank the event machine once.
// If there are no descriptors to process, then sleep
// for a few hundred mills to avoid busy-looping.
// This is based on a select loop. Alternately provide epoll
// if we know we're running on a 2.6 kernel.
// epoll will be effective if we provide it as an alternative,
// however it has the same problem interoperating with Ruby
// threads that select does.
SelectData_t SelectData;
/*
fd_set fdreads, fdwrites;
FD_ZERO (&fdreads);
FD_ZERO (&fdwrites);
int maxsocket = 0;
*/
// Always read the loop-breaker reader.
// Changed 23Aug06, provisionally implemented for Windows with a UDP socket
// running on localhost with a randomly-chosen port. (*Puke*)
// Windows has a version of the Unix pipe() library function, but it doesn't
// give you back descriptors that are selectable.
FD_SET (LoopBreakerReader, &(SelectData.fdreads));
if (SelectData.maxsocket < LoopBreakerReader)
SelectData.maxsocket = LoopBreakerReader;
// prepare the sockets for reading and writing
size_t i;
for (i = 0; i < Descriptors.size(); i++) {
EventableDescriptor *ed = Descriptors[i];
assert (ed);
int sd = ed->GetSocket();
if (ed->IsWatchOnly() && sd == INVALID_SOCKET)
continue;
assert (sd != INVALID_SOCKET);
if (ed->SelectForRead())
FD_SET (sd, &(SelectData.fdreads));
if (ed->SelectForWrite())
FD_SET (sd, &(SelectData.fdwrites));
#ifdef OS_WIN32
/* 21Sep09: on windows, a non-blocking connect() that fails does not come up as writable.
Instead, it is added to the error set. See http://www.mail-archive.com/[email protected]/msg58500.html
*/
FD_SET (sd, &(SelectData.fderrors));
#endif
if (SelectData.maxsocket < sd)
SelectData.maxsocket = sd;
}
{ // read and write the sockets
//timeval tv = {1, 0}; // Solaris fails if the microseconds member is >= 1000000.
//timeval tv = Quantum;
SelectData.tv = _TimeTilNextEvent();
int s = SelectData._Select();
//rb_thread_blocking_region(xxx,(void*)&SelectData,RUBY_UBF_IO,0);
//int s = EmSelect (SelectData.maxsocket+1, &(SelectData.fdreads), &(SelectData.fdwrites), NULL, &(SelectData.tv));
//int s = SelectData.nSockets;
if (s > 0) {
/* Changed 01Jun07. We used to handle the Loop-breaker right here.
* Now we do it AFTER all the regular descriptors. There's an
* incredibly important and subtle reason for this. Code on
* loop breakers is sometimes used to cause the reactor core to
* cycle (for example, to allow outbound network buffers to drain).
* If a loop-breaker handler reschedules itself (say, after determining
* that the write buffers are still too full), then it will execute
* IMMEDIATELY if _ReadLoopBreaker is done here instead of after
* the other descriptors are processed. That defeats the whole purpose.
*/
for (i=0; i < Descriptors.size(); i++) {
EventableDescriptor *ed = Descriptors[i];
assert (ed);
int sd = ed->GetSocket();
if (ed->IsWatchOnly() && sd == INVALID_SOCKET)
continue;
assert (sd != INVALID_SOCKET);
if (FD_ISSET (sd, &(SelectData.fdwrites)))
ed->Write();
if (FD_ISSET (sd, &(SelectData.fdreads)))
ed->Read();
if (FD_ISSET (sd, &(SelectData.fderrors)))
ed->HandleError();
}
if (FD_ISSET (LoopBreakerReader, &(SelectData.fdreads)))
_ReadLoopBreaker();
}
else if (s < 0) {
switch (errno) {
case EBADF:
_CleanBadDescriptors();
break;
case EINVAL:
throw std::runtime_error ("Somehow EM passed an invalid nfds or invalid timeout to select(2), please report this!");
break;
default:
// select can fail on error in a handful of ways.
// If this happens, then wait for a little while to avoid busy-looping.
// If the error was EINTR, we probably caught SIGCHLD or something,
// so keep the wait short.
timeval tv = {0, ((errno == EINTR) ? 5 : 50) * 1000};
EmSelect (0, NULL, NULL, NULL, &tv);
}
}
}
}
void EventMachine_t::_CleanBadDescriptors()
{
size_t i;
for (i = 0; i < Descriptors.size(); i++) {
EventableDescriptor *ed = Descriptors[i];
if (ed->ShouldDelete())
continue;
int sd = ed->GetSocket();
struct timeval tv;
tv.tv_sec = 0;
tv.tv_usec = 0;
fd_set fds;
FD_ZERO(&fds);
FD_SET(sd, &fds);
int ret = select(sd + 1, &fds, NULL, NULL, &tv);
if (ret == -1) {
if (errno == EBADF)
ed->ScheduleClose(false);
}
}
}
/********************************
EventMachine_t::_ReadLoopBreaker
********************************/
void EventMachine_t::_ReadLoopBreaker()
{