OW_Select.cpp

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#include "OW_config.h"
#include "OW_Select.hpp"
#include "OW_AutoPtr.hpp"
#include "OW_Assertion.hpp"
#include "OW_Thread.hpp" // for testCancel()

#if defined(OW_WIN32)
#include <cassert>
#endif

extern "C"
{

#ifndef OW_WIN32
 #ifdef OW_HAVE_SYS_EPOLL_H
  #include <sys/epoll.h>
 #endif
 #if defined (OW_HAVE_SYS_POLL_H)
  #include <sys/poll.h>
 #endif
 #if defined (OW_HAVE_SYS_SELECT_H)
  #include <sys/select.h>
 #endif
#endif

#ifdef OW_HAVE_SYS_TIME_H
 #include <sys/time.h>
#endif

#include <sys/types.h>

#ifdef OW_HAVE_UNISTD_H
 #include <unistd.h>
#endif

#include <errno.h>
}

namespace OW_NAMESPACE
{

namespace Select
{
#if defined(OW_WIN32)

int
selectRW(SelectObjectArray& selarray, UInt32 ms)
{
   int rc;
   size_t hcount = static_cast<DWORD>(selarray.size());
   AutoPtrVec<HANDLE> hdls(new HANDLE[hcount]);

   size_t handleidx = 0;
   for (size_t i = 0; i < selarray.size(); i++, handleidx++)
   {
      if(selarray[i].s.sockfd != INVALID_SOCKET
         && selarray[i].s.networkevents)
      {
         ::WSAEventSelect(selarray[i].s.sockfd, 
            selarray[i].s.event, selarray[i].s.networkevents);
      }
            
      hdls[handleidx] = selarray[i].s.event;
   }

   DWORD timeout = (ms != ~0U) ? ms : INFINITE;
   DWORD cc = ::WaitForMultipleObjects(hcount, hdls.get(), FALSE, timeout);

   assert(cc != WAIT_ABANDONED);

   switch (cc)
   {
      case WAIT_FAILED:
         rc = Select::SELECT_ERROR;
         break;
      case WAIT_TIMEOUT:
         rc = Select::SELECT_TIMEOUT;
         break;
      default:
         rc = cc - WAIT_OBJECT_0;
         
         // If this is a socket, set it back to 
         // blocking mode
         if(selarray[rc].s.sockfd != INVALID_SOCKET)
         {
            if(selarray[rc].s.networkevents
               && selarray[rc].s.doreset == false)
            {
               ::WSAEventSelect(selarray[rc].s.sockfd, 
                  selarray[rc].s.event, selarray[rc].s.networkevents);
            }
            else
            {
               // Set socket back to blocking
               ::WSAEventSelect(selarray[rc].s.sockfd, 
                  selarray[rc].s.event, 0);
               u_long ioctlarg = 0;
               ::ioctlsocket(selarray[rc].s.sockfd, FIONBIO, &ioctlarg);
            }
         }
         break;
   }

   if( rc < 0 )
      return rc;

   int availableCount = 0;
   for (size_t i = 0; i < selarray.size(); i++)
   {
      if( WaitForSingleObject(selarray[i].s.event, 0) == WAIT_OBJECT_0 )
      {
         if( selarray[i].waitForRead )
            selarray[i].readAvailable = true;
         if( selarray[i].waitForWrite )
            selarray[i].writeAvailable = true;
         ++availableCount;
      }
      else
      {
         selarray[i].readAvailable = false;
         selarray[i].writeAvailable = false;
      }
   }
   return availableCount;
}


#else

// epoll version
int
selectRWEpoll(SelectObjectArray& selarray, UInt32 ms)
{
#ifdef OW_HAVE_SYS_EPOLL_H
   int lerrno, ecc = 0;
   int timeout;
   AutoPtrVec<epoll_event> events(new epoll_event[selarray.size()]);
   int epfd = epoll_create(selarray.size());
   if(epfd == -1)
   {
      if (errno == ENOSYS) // kernel doesn't support it
      {
         return SELECT_NOT_IMPLEMENTED;
      }
      // Need to return something else?
      return Select::SELECT_ERROR;
   }

   UInt32 const read_events = EPOLLIN | EPOLLPRI | EPOLLERR | EPOLLHUP;
   UInt32 const write_events = EPOLLOUT | EPOLLERR | EPOLLHUP;
   for (size_t i = 0; i < selarray.size(); i++)
   {
      OW_ASSERT(selarray[i].s >= 0);
      selarray[i].readAvailable = false;
      selarray[i].writeAvailable = false;
      selarray[i].wasError = false;
      events[i].data.u32 = i;
      events[i].events = 0;
      if(selarray[i].waitForRead)
      {
         events[i].events |= read_events;
      }
      if(selarray[i].waitForWrite)
      {
         events[i].events |= write_events;
      }

      if(epoll_ctl(epfd, EPOLL_CTL_ADD, selarray[i].s, &events[i]) != 0)
      {
         int errnum = errno;
			::close(epfd);
         // Need to return something else?
         return errnum == EPERM ? SELECT_NOT_IMPLEMENTED : SELECT_ERROR;
      }
   }

   // here we spin checking for thread cancellation every so often.
   const Int32 loopMicroSeconds = 100 * 1000; // 1/10 of a second
   timeval now, end;
   gettimeofday(&now, NULL);
   end = now;
   end.tv_sec  += ms / 1000;
   end.tv_usec += (ms % 1000) * 1000;

   while ((ecc == 0) && ((ms == INFINITE_TIMEOUT) || (now.tv_sec < end.tv_sec)
       || ((now.tv_sec == end.tv_sec) && (now.tv_usec <= end.tv_usec))))
   {
      timeval tv;
      tv.tv_sec = end.tv_sec - now.tv_sec;
      if (end.tv_usec >= now.tv_usec)
      {
         tv.tv_usec = end.tv_usec - now.tv_usec;
      }
      else
      {
         tv.tv_sec--;
         tv.tv_usec = 1000000 + end.tv_usec - now.tv_usec;
      }

      if ((tv.tv_sec != 0) 
         || (tv.tv_usec > loopMicroSeconds) || (ms == INFINITE_TIMEOUT))
      {
         tv.tv_sec = 0;
         tv.tv_usec = loopMicroSeconds;
      }

      timeout = (tv.tv_sec * 1000) + (tv.tv_usec / 1000);
      Thread::testCancel();
      ecc = epoll_wait(epfd, events.get(), selarray.size(), timeout);
      lerrno = errno;
      Thread::testCancel();
      gettimeofday(&now, NULL);
   }

	::close(epfd);
   if (ecc < 0)
   {
      return (lerrno == EINTR) ? Select::SELECT_INTERRUPTED : Select::SELECT_ERROR;
   }
   if (ecc == 0)
   {
      return Select::SELECT_TIMEOUT;
   }

   for(int i = 0; i < ecc; i++)
   {
      SelectObject & so = selarray[events[i].data.u32];
      so.readAvailable = so.waitForRead && (events[i].events & read_events);
      so.writeAvailable = so.waitForWrite && (events[i].events & write_events);
   }

   return ecc;
#else
   return SELECT_NOT_IMPLEMENTED;
#endif
}

// poll() version
int
selectRWPoll(SelectObjectArray& selarray, UInt32 ms)
{
#if defined (OW_HAVE_SYS_POLL_H)
   int lerrno, rc = 0;

   AutoPtrVec<pollfd> pfds(new pollfd[selarray.size()]);

   // here we spin checking for thread cancellation every so often.
   timeval now, end;
   const Int32 loopMicroSeconds = 100 * 1000; // 1/10 of a second
   gettimeofday(&now, NULL);
   end = now;
   end.tv_sec  += ms / 1000;
   end.tv_usec += (ms % 1000) * 1000;
   while ((rc == 0) && ((ms == INFINITE_TIMEOUT) || (now.tv_sec < end.tv_sec)
       || ((now.tv_sec == end.tv_sec) && (now.tv_usec <= end.tv_usec))))
   {
      for (size_t i = 0; i < selarray.size(); i++)
      {
         OW_ASSERT(selarray[i].s >= 0);
         selarray[i].readAvailable = false;
         selarray[i].writeAvailable = false;
         selarray[i].wasError = false;
         pfds[i].revents = 0;
         pfds[i].fd = selarray[i].s;
         pfds[i].events = selarray[i].waitForRead ? (POLLIN | POLLPRI) : 0;
         if(selarray[i].waitForWrite)
            pfds[i].events |= POLLOUT;
      }

      timeval tv;
      tv.tv_sec = end.tv_sec - now.tv_sec;
      if (end.tv_usec >= now.tv_usec)
      {
         tv.tv_usec = end.tv_usec - now.tv_usec;
      }
      else
      {
         tv.tv_sec--;
         tv.tv_usec = 1000000 + end.tv_usec - now.tv_usec;
      }

      if ((tv.tv_sec != 0) || (tv.tv_usec > loopMicroSeconds) || (ms == INFINITE_TIMEOUT))
      {
         tv.tv_sec = 0;
         tv.tv_usec = loopMicroSeconds;
      }

      // TODO optimize this. 
      int loopMSecs = tv.tv_sec * 1000 + tv.tv_usec / 1000; 

      Thread::testCancel();
      rc = ::poll(pfds.get(), selarray.size(), loopMSecs); 
      lerrno = errno;
      Thread::testCancel();

      gettimeofday(&now, NULL);
   }
   
   if (rc < 0)
   {
      if (lerrno == EINTR)
      {
#ifdef OW_NETWARE
         // When the NetWare server is shutting down, select will
         // set errno to EINTR on return. If this thread does not
         // yield control (cooperative multitasking) then we end
         // up in a very tight loop and get a CPUHog server abbend.
         pthread_yield();
#endif
         return Select::SELECT_INTERRUPTED;
      }
      else
      {
         return Select::SELECT_ERROR;
      }
   }
   if (rc == 0)
   {
      return Select::SELECT_TIMEOUT;
   }
   for (size_t i = 0; i < selarray.size(); i++)
   {
      if (pfds[i].revents & (POLLERR | POLLNVAL))
      {
         selarray[i].wasError = true;
      }
      else
      {
         if(selarray[i].waitForRead)
         {
            selarray[i].readAvailable = (pfds[i].revents & 
               (POLLIN | POLLPRI | POLLHUP));
         }

         if(selarray[i].waitForWrite)
         {
            selarray[i].writeAvailable = (pfds[i].revents &
               (POLLOUT | POLLHUP));
         }
      }
   }

   return rc;
#else
   return SELECT_NOT_IMPLEMENTED;
#endif
}
// ::select() version
int
selectRWSelect(SelectObjectArray& selarray, UInt32 ms)
{
#if defined (OW_HAVE_SYS_SELECT_H)
   int lerrno, rc = 0;
   fd_set ifds;
   fd_set ofds;

   // here we spin checking for thread cancellation every so often.
   timeval now, end;
   const Int32 loopMicroSeconds = 100 * 1000; // 1/10 of a second
   gettimeofday(&now, NULL);
   end = now;
   end.tv_sec  += ms / 1000;
   end.tv_usec += (ms % 1000) * 1000;
   while ((rc == 0) && ((ms == INFINITE_TIMEOUT) || (now.tv_sec < end.tv_sec)
       || ((now.tv_sec == end.tv_sec) && (now.tv_usec <= end.tv_usec))))
   {
      int maxfd = 0;
      FD_ZERO(&ifds);
      FD_ZERO(&ofds);
      for (size_t i = 0; i < selarray.size(); ++i)
      {
         int fd = selarray[i].s;
         OW_ASSERT(fd >= 0);
         if (maxfd < fd)
         {
            maxfd = fd;
         }
         if (fd < 0 || fd >= FD_SETSIZE)
         {
            return Select::SELECT_ERROR;
         }
         if (selarray[i].waitForRead)
         {
            FD_SET(fd, &ifds);
         }
         if (selarray[i].waitForWrite)
         {
            FD_SET(fd, &ofds);
         }
      }

      timeval tv;
      tv.tv_sec = end.tv_sec - now.tv_sec;
      if (end.tv_usec >= now.tv_usec)
      {
         tv.tv_usec = end.tv_usec - now.tv_usec;
      }
      else
      {
         tv.tv_sec--;
         tv.tv_usec = 1000000 + end.tv_usec - now.tv_usec;
      }

      if ((tv.tv_sec != 0) || (tv.tv_usec > loopMicroSeconds) || (ms == INFINITE_TIMEOUT))
      {
         tv.tv_sec = 0;
         tv.tv_usec = loopMicroSeconds;
      }

      Thread::testCancel();
      rc = ::select(maxfd+1, &ifds, &ofds, NULL, &tv);
      lerrno = errno;
      Thread::testCancel();

      gettimeofday(&now, NULL);
   }
   
   if (rc < 0)
   {
      if (lerrno == EINTR)
      {
#ifdef OW_NETWARE
         // When the NetWare server is shutting down, select will
         // set errno to EINTR on return. If this thread does not
         // yield control (cooperative multitasking) then we end
         // up in a very tight loop and get a CPUHog server abbend.
         pthread_yield();
#endif
         return Select::SELECT_INTERRUPTED;
      }
      else
      {
         return Select::SELECT_ERROR;
      }
   }
   if (rc == 0)
   {
      return Select::SELECT_TIMEOUT;
   }
   int availableCount = 0;
   int cval;
   for (size_t i = 0; i < selarray.size(); i++)
   {
      selarray[i].wasError = false;
      cval = 0;
      if (FD_ISSET(selarray[i].s, &ifds))
      {
         selarray[i].readAvailable = true;
         cval = 1;
      }
      else
      {
         selarray[i].readAvailable = false;
      }

      if (FD_ISSET(selarray[i].s, &ofds))
      {
         selarray[i].writeAvailable = true;
         cval = 1;
      }
      else
      {
         selarray[i].writeAvailable = false;
      }

      availableCount += cval;

   }
      
   return availableCount;
#else
   return SELECT_NOT_IMPLEMENTED;
#endif
}

int
selectRW(SelectObjectArray& selarray, UInt32 ms)
{
   int rv = selectRWEpoll(selarray, ms);
   if (rv != SELECT_NOT_IMPLEMENTED)
   {
      return rv;
   }

   rv = selectRWPoll(selarray, ms);
   if (rv != SELECT_NOT_IMPLEMENTED)
   {
      return rv;
   }

   rv = selectRWSelect(selarray, ms);
   OW_ASSERT(rv != SELECT_NOT_IMPLEMENTED);
   return rv;
}

#endif   // #else OW_WIN32

int
select(const SelectTypeArray& selarray, UInt32 ms)
{
   SelectObjectArray soa;
   soa.reserve(selarray.size());
   for (size_t i = 0; i < selarray.size(); ++i)
   {
      SelectObject curObj(selarray[i]);
      curObj.waitForRead = true;
      soa.push_back(curObj);
   }
   int rv = selectRW(soa, ms);
   if (rv < 0)
   {
      return rv;
   }

   // find the first selected object
   for (size_t i = 0; i < soa.size(); ++i)
   {
      if (soa[i].readAvailable)
      {
         return i;
      }
   }
   return SELECT_ERROR;
}

} // end namespace Select

} // end namespace OW_NAMESPACE

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