/* Emulation for poll(2)

   Contributed by Paolo Bonzini.

   Copyright 2001-2003, 2006-2018 Free Software Foundation, Inc.

   This file is part of gnulib.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3, or (at your option)

   any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License along

   with this program; if not, see <https://www.gnu.org/licenses/>.  */

/* Tell gcc not to warn about the (nfd < 0) tests, below.  */

#if (__GNUC__ == 4 && 3 <= __GNUC_MINOR__) || 4 < __GNUC__

# pragma GCC diagnostic ignored "-Wtype-limits"

#endif

#include <config.h>

#include <alloca.h>

#include <sys/types.h>

/* Specification.  */

#include <poll.h>

#include <errno.h>

#include <limits.h>

#if defined _WIN32 && ! defined __CYGWIN__

# define WINDOWS_NATIVE

# include <winsock2.h>

# include <windows.h>

# include <io.h>

# include <stdio.h>

# include <conio.h>

# if GNULIB_MSVC_NOTHROW

#  include "msvc-nothrow.h"

# else

#  include <io.h>

# endif

#else

# include <sys/time.h>

# include <unistd.h>

#endif

#include <sys/select.h>

#include <sys/socket.h>

#ifdef HAVE_SYS_IOCTL_H

# include <sys/ioctl.h>

#endif

#ifdef HAVE_SYS_FILIO_H

# include <sys/filio.h>

#endif

#include <time.h>

#include "assure.h"

#ifndef INFTIM

# define INFTIM (-1)

#endif

/* BeOS does not have MSG_PEEK.  */

#ifndef MSG_PEEK

# define MSG_PEEK 0

#endif

#ifdef WINDOWS_NATIVE

/* Here we need the recv() function from Windows, that takes a SOCKET as

   first argument, not any possible gnulib override.  */

# undef recv

/* Here we need the select() function from Windows, because we pass bit masks

   of SOCKETs, not bit masks of FDs.  */

# undef select

static BOOL IsConsoleHandle (HANDLE h)

{

  DWORD mode;

  return GetConsoleMode (h, &mode) != 0;

}

static BOOL

IsSocketHandle (HANDLE h)

{

  WSANETWORKEVENTS ev;

  if (IsConsoleHandle (h))

    return FALSE;

  /* Under Wine, it seems that getsockopt returns 0 for pipes too.

     WSAEnumNetworkEvents instead distinguishes the two correctly.  */

  ev.lNetworkEvents = 0xDEADBEEF;

  WSAEnumNetworkEvents ((SOCKET) h, NULL, &ev;;

  return ev.lNetworkEvents != 0xDEADBEEF;

}

/* Declare data structures for ntdll functions.  */

typedef struct _FILE_PIPE_LOCAL_INFORMATION {

  ULONG NamedPipeType;

  ULONG NamedPipeConfiguration;

  ULONG MaximumInstances;

  ULONG CurrentInstances;

  ULONG InboundQuota;

  ULONG ReadDataAvailable;

  ULONG OutboundQuota;

  ULONG WriteQuotaAvailable;

  ULONG NamedPipeState;

  ULONG NamedPipeEnd;

} FILE_PIPE_LOCAL_INFORMATION, *PFILE_PIPE_LOCAL_INFORMATION;

typedef struct _IO_STATUS_BLOCK

{

  union {

    DWORD Status;

    PVOID Pointer;

  } u;

  ULONG_PTR Information;

} IO_STATUS_BLOCK, *PIO_STATUS_BLOCK;

typedef enum _FILE_INFORMATION_CLASS {

  FilePipeLocalInformation = 24

} FILE_INFORMATION_CLASS, *PFILE_INFORMATION_CLASS;

typedef DWORD (WINAPI *PNtQueryInformationFile)

         (HANDLE, IO_STATUS_BLOCK *, VOID *, ULONG, FILE_INFORMATION_CLASS);

# ifndef PIPE_BUF

#  define PIPE_BUF      512

# endif

/* Compute revents values for file handle H.  If some events cannot happen

   for the handle, eliminate them from *P_SOUGHT.  */

static int

windows_compute_revents (HANDLE h, int *p_sought)

{

  int i, ret, happened;

  INPUT_RECORD *irbuffer;

  DWORD avail, nbuffer;

  BOOL bRet;

  IO_STATUS_BLOCK iosb;

  FILE_PIPE_LOCAL_INFORMATION fpli;

  static PNtQueryInformationFile NtQueryInformationFile;

  static BOOL once_only;

  switch (GetFileType (h))

    {

    case FILE_TYPE_PIPE:

      if (!once_only)

        {

          NtQueryInformationFile = (PNtQueryInformationFile)

            GetProcAddress (GetModuleHandle ("ntdll.dll"),

                            "NtQueryInformationFile");

          once_only = TRUE;

        }

      happened = 0;

      if (PeekNamedPipe (h, NULL, 0, NULL, &avail, NULL) != 0)

        {

          if (avail)

            happened |= *p_sought & (POLLIN | POLLRDNORM);

        }

      else if (GetLastError () == ERROR_BROKEN_PIPE)

        happened |= POLLHUP;

      else

        {

          /* It was the write-end of the pipe.  Check if it is writable.

             If NtQueryInformationFile fails, optimistically assume the pipe is

             writable.  This could happen on Windows 9x, where

             NtQueryInformationFile is not available, or if we inherit a pipe

             that doesn't permit FILE_READ_ATTRIBUTES access on the write end

             (I think this should not happen since Windows XP SP2; WINE seems

             fine too).  Otherwise, ensure that enough space is available for

             atomic writes.  */

          memset (&iosb, 0, sizeof (iosb));

          memset (&fpli, 0, sizeof (fpli));

          if (!NtQueryInformationFile

              || NtQueryInformationFile (h, &iosb, &fpli, sizeof (fpli),

                                         FilePipeLocalInformation)

              || fpli.WriteQuotaAvailable >= PIPE_BUF

              || (fpli.OutboundQuota < PIPE_BUF &&

                  fpli.WriteQuotaAvailable == fpli.OutboundQuota))

            happened |= *p_sought & (POLLOUT | POLLWRNORM | POLLWRBAND);

        }

      return happened;

    case FILE_TYPE_CHAR:

      ret = WaitForSingleObject (h, 0);

      if (!IsConsoleHandle (h))

        return ret == WAIT_OBJECT_0 ? *p_sought & ~(POLLPRI | POLLRDBAND) : 0;

      nbuffer = avail = 0;

      bRet = GetNumberOfConsoleInputEvents (h, &nbuffer);

      if (bRet)

        {

          /* Input buffer.  */

          *p_sought &= POLLIN | POLLRDNORM;

          if (nbuffer == 0)

            return POLLHUP;

          if (!*p_sought)

            return 0;

          irbuffer = (INPUT_RECORD *) alloca (nbuffer * sizeof (INPUT_RECORD));

          bRet = PeekConsoleInput (h, irbuffer, nbuffer, &avail);

          if (!bRet || avail == 0)

            return POLLHUP;

          for (i = 0; i < avail; i++)

            if (irbuffer[i].EventType == KEY_EVENT)

              return *p_sought;

          return 0;

        }

      else

        {

          /* Screen buffer.  */

          *p_sought &= POLLOUT | POLLWRNORM | POLLWRBAND;

          return *p_sought;

        }

    default:

      ret = WaitForSingleObject (h, 0);

      if (ret == WAIT_OBJECT_0)

        return *p_sought & ~(POLLPRI | POLLRDBAND);

      return *p_sought & (POLLOUT | POLLWRNORM | POLLWRBAND);

    }

}

/* Convert fd_sets returned by select into revents values.  */

static int

windows_compute_revents_socket (SOCKET h, int sought, long lNetworkEvents)

{

  int happened = 0;

  if ((lNetworkEvents & (FD_READ | FD_ACCEPT | FD_CLOSE)) == FD_ACCEPT)

    happened |= (POLLIN | POLLRDNORM) & sought;

  else if (lNetworkEvents & (FD_READ | FD_ACCEPT | FD_CLOSE))

    {

      int r, error;

      char data[64];

      WSASetLastError (0);

      r = recv (h, data, sizeof (data), MSG_PEEK);

      error = WSAGetLastError ();

      WSASetLastError (0);

      if (r > 0 || error == WSAENOTCONN)

        happened |= (POLLIN | POLLRDNORM) & sought;

      /* Distinguish hung-up sockets from other errors.  */

      else if (r == 0 || error == WSAESHUTDOWN || error == WSAECONNRESET

               || error == WSAECONNABORTED || error == WSAENETRESET)

        happened |= POLLHUP;

      else

        happened |= POLLERR;

    }

  if (lNetworkEvents & (FD_WRITE | FD_CONNECT))

    happened |= (POLLOUT | POLLWRNORM | POLLWRBAND) & sought;

  if (lNetworkEvents & FD_OOB)

    happened |= (POLLPRI | POLLRDBAND) & sought;

  return happened;

}

#else /* !MinGW */

/* Convert select(2) returned fd_sets into poll(2) revents values.  */

static int

compute_revents (int fd, int sought, fd_set *rfds, fd_set *wfds, fd_set *efds)

{

  int happened = 0;

  if (FD_ISSET (fd, rfds))

    {

      int r;

      int socket_errno;

# if defined __MACH__ && defined __APPLE__

      /* There is a bug in Mac OS X that causes it to ignore MSG_PEEK

         for some kinds of descriptors.  Detect if this descriptor is a

         connected socket, a server socket, or something else using a

         0-byte recv, and use ioctl(2) to detect POLLHUP.  */

      r = recv (fd, NULL, 0, MSG_PEEK);

      socket_errno = (r < 0) ? errno : 0;

      if (r == 0 || socket_errno == ENOTSOCK)

        ioctl (fd, FIONREAD, &r);

# else

      char data[64];

      r = recv (fd, data, sizeof (data), MSG_PEEK);

      socket_errno = (r < 0) ? errno : 0;

# endif

      if (r == 0)

        happened |= POLLHUP;

      /* If the event happened on an unconnected server socket,

         that's fine. */

      else if (r > 0 || ( /* (r == -1) && */ socket_errno == ENOTCONN))

        happened |= (POLLIN | POLLRDNORM) & sought;

      /* Distinguish hung-up sockets from other errors.  */

      else if (socket_errno == ESHUTDOWN || socket_errno == ECONNRESET

               || socket_errno == ECONNABORTED || socket_errno == ENETRESET)

        happened |= POLLHUP;

      /* some systems can't use recv() on non-socket, including HP NonStop */

      else if (socket_errno == ENOTSOCK)

        happened |= (POLLIN | POLLRDNORM) & sought;

      else

        happened |= POLLERR;

    }

  if (FD_ISSET (fd, wfds))

    happened |= (POLLOUT | POLLWRNORM | POLLWRBAND) & sought;

  if (FD_ISSET (fd, efds))

    happened |= (POLLPRI | POLLRDBAND) & sought;

  return happened;

}

#endif /* !MinGW */

int

poll (struct pollfd *pfd, nfds_t nfd, int timeout)

{

#ifndef WINDOWS_NATIVE

  fd_set rfds, wfds, efds;

  struct timeval tv;

  struct timeval *ptv;

  int maxfd, rc;

  nfds_t i;

  if (nfd > INT_MAX)

    {

      errno = EINVAL;

      return -1;

    }

  /* Don't check directly for NFD greater than OPEN_MAX.  Any practical use

     of a too-large NFD is caught by one of the other checks below, and

     checking directly for getdtablesize is too much of a portability

     and/or performance and/or correctness hassle.  */

  /* EFAULT is not necessary to implement, but let's do it in the

     simplest case. */

  if (!pfd && nfd)

    {

      errno = EFAULT;

      return -1;

    }

  /* convert timeout number into a timeval structure */

  if (timeout == 0)

    {

      ptv = &tv;

      ptv->tv_sec = 0;

      ptv->tv_usec = 0;

    }

  else if (timeout > 0)

    {

      ptv = &tv;

      ptv->tv_sec = timeout / 1000;

      ptv->tv_usec = (timeout % 1000) * 1000;

    }

  else if (timeout == INFTIM)

    /* wait forever */

    ptv = NULL;

  else

    {

      errno = EINVAL;

      return -1;

    }

  /* create fd sets and determine max fd */

  maxfd = -1;

  FD_ZERO (&rfds);

  FD_ZERO (&wfds);

  FD_ZERO (&efds);

  for (i = 0; i < nfd; i++)

    {

      if (pfd[i].fd < 0)

        continue;

      if (maxfd < pfd[i].fd)

        {

          maxfd = pfd[i].fd;

          if (FD_SETSIZE <= maxfd)

            {

              errno = EINVAL;

              return -1;

            }

        }

      if (pfd[i].events & (POLLIN | POLLRDNORM))

        FD_SET (pfd[i].fd, &rfds);

      /* see select(2): "the only exceptional condition detectable

         is out-of-band data received on a socket", hence we push

         POLLWRBAND events onto wfds instead of efds. */

      if (pfd[i].events & (POLLOUT | POLLWRNORM | POLLWRBAND))

        FD_SET (pfd[i].fd, &wfds);

      if (pfd[i].events & (POLLPRI | POLLRDBAND))

        FD_SET (pfd[i].fd, &efds);

    }

  /* examine fd sets */

  rc = select (maxfd + 1, &rfds, &wfds, &efds, ptv);

  if (rc < 0)

    return rc;

  /* establish results */

  rc = 0;

  for (i = 0; i < nfd; i++)

    {

      pfd[i].revents = (pfd[i].fd < 0

                        ? 0

                        : compute_revents (pfd[i].fd, pfd[i].events,

                                           &rfds, &wfds, &efds));

      rc += pfd[i].revents != 0;

    }

  return rc;

#else

  static struct timeval tv0;

  static HANDLE hEvent;

  WSANETWORKEVENTS ev;

  HANDLE h, handle_array[FD_SETSIZE + 2];

  DWORD ret, wait_timeout, nhandles;

  fd_set rfds, wfds, xfds;

  BOOL poll_again;

  MSG msg;

  int rc = 0;

  nfds_t i;

  if (nfd > INT_MAX || timeout < -1)

    {

      errno = EINVAL;

      return -1;

    }

  if (!hEvent)

    hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);

restart:

  handle_array[0] = hEvent;

  nhandles = 1;

  FD_ZERO (&rfds);

  FD_ZERO (&wfds);

  FD_ZERO (&xfds);

  /* Classify socket handles and create fd sets. */

  for (i = 0; i < nfd; i++)

    {

      int sought = pfd[i].events;

      pfd[i].revents = 0;

      if (pfd[i].fd < 0)

        continue;

      if (!(sought & (POLLIN | POLLRDNORM | POLLOUT | POLLWRNORM | POLLWRBAND

                      | POLLPRI | POLLRDBAND)))

        continue;

      h = (HANDLE) _get_osfhandle (pfd[i].fd);

      assure (h != NULL);

      if (IsSocketHandle (h))

        {

          int requested = FD_CLOSE;

          /* see above; socket handles are mapped onto select.  */

          if (sought & (POLLIN | POLLRDNORM))

            {

              requested |= FD_READ | FD_ACCEPT;

              FD_SET ((SOCKET) h, &rfds);

            }

          if (sought & (POLLOUT | POLLWRNORM | POLLWRBAND))

            {

              requested |= FD_WRITE | FD_CONNECT;

              FD_SET ((SOCKET) h, &wfds);

            }

          if (sought & (POLLPRI | POLLRDBAND))

            {

              requested |= FD_OOB;

              FD_SET ((SOCKET) h, &xfds);

            }

          if (requested)

            WSAEventSelect ((SOCKET) h, hEvent, requested);

        }

      else

        {

          /* Poll now.  If we get an event, do not poll again.  Also,

             screen buffer handles are waitable, and they'll block until

             a character is available.  windows_compute_revents eliminates

             bits for the "wrong" direction. */

          pfd[i].revents = windows_compute_revents (h, &sought);

          if (sought)

            handle_array[nhandles++] = h;

          if (pfd[i].revents)

            timeout = 0;

        }

    }

  if (select (0, &rfds, &wfds, &xfds, &tv0) > 0)

    {

      /* Do MsgWaitForMultipleObjects anyway to dispatch messages, but

         no need to call select again.  */

      poll_again = FALSE;

      wait_timeout = 0;

    }

  else

    {

      poll_again = TRUE;

      if (timeout == INFTIM)

        wait_timeout = INFINITE;

      else

        wait_timeout = timeout;

    }

  for (;;)

    {

      ret = MsgWaitForMultipleObjects (nhandles, handle_array, FALSE,

                                       wait_timeout, QS_ALLINPUT);

      if (ret == WAIT_OBJECT_0 + nhandles)

        {

          /* new input of some other kind */

          BOOL bRet;

          while ((bRet = PeekMessage (&msg, NULL, 0, 0, PM_REMOVE)) != 0)

            {

              TranslateMessage (&msg;;

              DispatchMessage (&msg;;

            }

        }

      else

        break;

    }

  if (poll_again)

    select (0, &rfds, &wfds, &xfds, &tv0);

  /* Place a sentinel at the end of the array.  */

  handle_array[nhandles] = NULL;

  nhandles = 1;

  for (i = 0; i < nfd; i++)

    {

      int happened;

      if (pfd[i].fd < 0)

        continue;

      if (!(pfd[i].events & (POLLIN | POLLRDNORM |

                             POLLOUT | POLLWRNORM | POLLWRBAND)))

        continue;

      h = (HANDLE) _get_osfhandle (pfd[i].fd);

      if (h != handle_array[nhandles])

        {

          /* It's a socket.  */

          WSAEnumNetworkEvents ((SOCKET) h, NULL, &ev;;

          WSAEventSelect ((SOCKET) h, 0, 0);

          /* If we're lucky, WSAEnumNetworkEvents already provided a way

             to distinguish FD_READ and FD_ACCEPT; this saves a recv later.  */

          if (FD_ISSET ((SOCKET) h, &rfds)

              && !(ev.lNetworkEvents & (FD_READ | FD_ACCEPT)))

            ev.lNetworkEvents |= FD_READ | FD_ACCEPT;

          if (FD_ISSET ((SOCKET) h, &wfds))

            ev.lNetworkEvents |= FD_WRITE | FD_CONNECT;

          if (FD_ISSET ((SOCKET) h, &xfds))

            ev.lNetworkEvents |= FD_OOB;

          happened = windows_compute_revents_socket ((SOCKET) h, pfd[i].events,

                                                     ev.lNetworkEvents);

        }

      else

        {

          /* Not a socket.  */

          int sought = pfd[i].events;

          happened = windows_compute_revents (h, &sought);

          nhandles++;

        }

       if ((pfd[i].revents |= happened) != 0)

        rc++;

    }

  if (!rc && timeout == INFTIM)

    {

      SleepEx (1, TRUE);

      goto restart;

    }

  return rc;

#endif

}