Select.cpp

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* Copyright (C) 2006, Novell, Inc. All rights reserved.
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#include "blocxx/BLOCXX_config.h"
#include "blocxx/Select.hpp"
#include "blocxx/AutoPtr.hpp"
#include "blocxx/Assertion.hpp"
#include "blocxx/Thread.hpp" // for testCancel()
#include "blocxx/TimeoutTimer.hpp"
#include "blocxx/AutoDescriptor.hpp"
 
#if defined(BLOCXX_WIN32)
#include <cassert>
#endif
 
extern "C"
{
 
#ifndef BLOCXX_WIN32
 #ifdef BLOCXX_HAVE_SYS_EPOLL_H
  #include <sys/epoll.h>
 #endif
 #if defined (BLOCXX_HAVE_SYS_POLL_H)
  #include <sys/poll.h>
 #endif
 #if defined (BLOCXX_HAVE_SYS_SELECT_H)
  #include <sys/select.h>
 #endif
#endif
 
#ifdef BLOCXX_HAVE_SYS_TIME_H
 #include <sys/time.h>
#endif
 
#include <sys/types.h>
 
#ifdef BLOCXX_HAVE_UNISTD_H
 #include <unistd.h>
#endif
 
#include <errno.h>
}
 
namespace BLOCXX_NAMESPACE
{
 
namespace Select
{
 
namespace
{
   const float LOOP_TIMEOUT = 10.0;
}
// deprecated in 4.0.0
int
selectRW(SelectObjectArray& selarray, UInt32 ms)
{
   return selectRW(selarray, Timeout::relative(static_cast<float>(ms) * 1000));
}
 
#if defined(BLOCXX_WIN32)
int
selectRW(SelectObjectArray& selarray, const Timeout& timeout)
{
   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.isSocket && selarray[i].s.networkevents)
      {
         ::WSAEventSelect(selarray[i].s.sockfd, 
            selarray[i].s.event, selarray[i].s.networkevents);
      }
            
      hdls[handleidx] = selarray[i].s.event;
   }
 
   TimeoutTimer timer(timeout);
   timer.start();
   DWORD cc = ::WaitForMultipleObjects(hcount, hdls.get(), FALSE, timer.asDWORDMs());
 
   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.isSocket)
         {
            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, const Timeout& timeout)
{
#ifdef BLOCXX_HAVE_SYS_EPOLL_H
   int ecc = 0;
   AutoPtrVec<epoll_event> events(new epoll_event[selarray.size()]);
   AutoDescriptor epfd(epoll_create(selarray.size()));
   if(epfd.get() == -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++)
   {
      BLOCXX_ASSERT(selarray[i].s >= 0);
      selarray[i].readAvailable = false;
      selarray[i].writeAvailable = false;
      selarray[i].wasError = false;
      events[i].data = epoll_data_t(); // zero-init to make valgrind happy
      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.get(), EPOLL_CTL_ADD, selarray[i].s, &events[i]) != 0)
      {
         return errno == EPERM ? SELECT_NOT_IMPLEMENTED : SELECT_ERROR;
      }
   }
 
   // here we spin checking for thread cancellation every so often.
 
   TimeoutTimer timer(timeout);
   timer.start();
   int savedErrno;
   do
   {
      Thread::testCancel();
      const float maxWaitSec = LOOP_TIMEOUT;
      ecc = epoll_wait(epfd.get(), events.get(), selarray.size(), timer.asIntMs(maxWaitSec));
      savedErrno = errno;
      if (ecc < 0 && errno == EINTR)
      {
         ecc = 0;
         errno = 0;
         Thread::testCancel();
      }
      timer.loop();
   } while ((ecc == 0) && !timer.expired());
 
   if (ecc < 0)
   {
      errno = savedErrno;
      return 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, const Timeout& timeout)
{
#if defined (BLOCXX_HAVE_SYS_POLL_H)
   int rc = 0;
 
   AutoPtrVec<pollfd> pfds(new pollfd[selarray.size()]);
 
   // here we spin checking for thread cancellation every so often.
   TimeoutTimer timer(timeout);
   timer.start();
 
   int savedErrno;
   do
   {
      for (size_t i = 0; i < selarray.size(); i++)
      {
         BLOCXX_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;
      }
 
      Thread::testCancel();
      const float maxWaitSec = LOOP_TIMEOUT;
      rc = ::poll(pfds.get(), selarray.size(), timer.asIntMs(maxWaitSec));
      savedErrno = errno;
      if (rc < 0 && errno == EINTR)
      {
         rc = 0;
         errno = 0;
         Thread::testCancel();
#ifdef  BLOCXX_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
      }
 
      timer.loop();
   } while ((rc == 0) && !timer.expired());
   
   if (rc < 0)
   {
      errno = savedErrno;
      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;
      }
 
      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, const Timeout& timeout)
{
#if defined (BLOCXX_HAVE_SYS_SELECT_H)
   int rc = 0;
   fd_set ifds;
   fd_set ofds;
 
   // here we spin checking for thread cancellation every so often.
   TimeoutTimer timer(timeout);
   timer.start();
 
   int savedErrno;
   do
   {
      int maxfd = 0;
      FD_ZERO(&ifds);
      FD_ZERO(&ofds);
      for (size_t i = 0; i < selarray.size(); ++i)
      {
         int fd = selarray[i].s;
         BLOCXX_ASSERT(fd >= 0);
         if (maxfd < fd)
         {
            maxfd = fd;
         }
         if (fd < 0 || fd >= FD_SETSIZE)
         {
            errno = EINVAL;
            return Select::SELECT_ERROR;
         }
         if (selarray[i].waitForRead)
         {
            FD_SET(fd, &ifds);
         }
         if (selarray[i].waitForWrite)
         {
            FD_SET(fd, &ofds);
         }
      }
 
      Thread::testCancel();
      struct timeval tv;
      const float maxWaitSec = LOOP_TIMEOUT;
      rc = ::select(maxfd+1, &ifds, &ofds, NULL, timer.asTimeval(tv, maxWaitSec));
      savedErrno = errno;
      if (rc < 0 && errno == EINTR)
      {
         rc = 0;
         errno = 0;
         Thread::testCancel();
#ifdef  BLOCXX_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
      }
 
      timer.loop();
   } while ((rc == 0) && !timer.expired());
   
   if (rc < 0)
   {
      errno = savedErrno;
      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, const Timeout& timeout)
{
   int rv = selectRWEpoll(selarray, timeout);
   if (rv != SELECT_NOT_IMPLEMENTED)
   {
      return rv;
   }
 
   rv = selectRWPoll(selarray, timeout);
   if (rv != SELECT_NOT_IMPLEMENTED)
   {
      return rv;
   }
 
   rv = selectRWSelect(selarray, timeout);
   BLOCXX_ASSERT(rv != SELECT_NOT_IMPLEMENTED);
   return rv;
}
 
#endif   // #else BLOCXX_WIN32
 
int
select(const SelectTypeArray& selarray, UInt32 ms)
{
   return select(selarray, Timeout::relative(static_cast<float>(ms) * 1000.0));
}
 
int
select(const SelectTypeArray& selarray, const Timeout& timeout)
{
   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, timeout);
   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;
      }
   }
   errno = 0;
   return SELECT_ERROR;
}
 
} // end namespace Select
 
} // end namespace BLOCXX_NAMESPACE