584 lines
16 KiB
C
584 lines
16 KiB
C
/* Emulation for select(2)
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Contributed by Paolo Bonzini.
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Copyright 2008-2020 Free Software Foundation, Inc.
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This file is part of gnulib.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along
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with this program; if not, see <https://www.gnu.org/licenses/>. */
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#include <config.h>
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#include <alloca.h>
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#include <assert.h>
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#if defined _WIN32 && ! defined __CYGWIN__
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/* Native Windows. */
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#include <sys/types.h>
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#include <errno.h>
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#include <limits.h>
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#include <winsock2.h>
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#include <windows.h>
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#include <io.h>
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#include <stdio.h>
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#include <conio.h>
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#include <time.h>
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/* Get the overridden 'struct timeval'. */
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#include <sys/time.h>
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#if GNULIB_MSVC_NOTHROW
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# include "msvc-nothrow.h"
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#else
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# include <io.h>
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#endif
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#undef select
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/* Avoid warnings from gcc -Wcast-function-type. */
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#define GetProcAddress \
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(void *) GetProcAddress
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struct bitset {
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unsigned char in[FD_SETSIZE / CHAR_BIT];
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unsigned char out[FD_SETSIZE / CHAR_BIT];
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};
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/* Declare data structures for ntdll functions. */
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typedef struct _FILE_PIPE_LOCAL_INFORMATION {
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ULONG NamedPipeType;
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ULONG NamedPipeConfiguration;
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ULONG MaximumInstances;
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ULONG CurrentInstances;
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ULONG InboundQuota;
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ULONG ReadDataAvailable;
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ULONG OutboundQuota;
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ULONG WriteQuotaAvailable;
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ULONG NamedPipeState;
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ULONG NamedPipeEnd;
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} FILE_PIPE_LOCAL_INFORMATION, *PFILE_PIPE_LOCAL_INFORMATION;
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typedef struct _IO_STATUS_BLOCK
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{
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union {
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DWORD Status;
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PVOID Pointer;
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} u;
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ULONG_PTR Information;
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} IO_STATUS_BLOCK, *PIO_STATUS_BLOCK;
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typedef enum _FILE_INFORMATION_CLASS {
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FilePipeLocalInformation = 24
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} FILE_INFORMATION_CLASS, *PFILE_INFORMATION_CLASS;
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typedef DWORD (WINAPI *PNtQueryInformationFile)
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(HANDLE, IO_STATUS_BLOCK *, VOID *, ULONG, FILE_INFORMATION_CLASS);
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#ifndef PIPE_BUF
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#define PIPE_BUF 512
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#endif
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static BOOL IsConsoleHandle (HANDLE h)
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{
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DWORD mode;
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return GetConsoleMode (h, &mode) != 0;
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}
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static BOOL
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IsSocketHandle (HANDLE h)
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{
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WSANETWORKEVENTS ev;
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if (IsConsoleHandle (h))
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return FALSE;
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/* Under Wine, it seems that getsockopt returns 0 for pipes too.
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WSAEnumNetworkEvents instead distinguishes the two correctly. */
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ev.lNetworkEvents = 0xDEADBEEF;
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WSAEnumNetworkEvents ((SOCKET) h, NULL, &ev);
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return ev.lNetworkEvents != 0xDEADBEEF;
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}
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/* Compute output fd_sets for libc descriptor FD (whose Windows handle is
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H). */
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static int
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windows_poll_handle (HANDLE h, int fd,
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struct bitset *rbits,
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struct bitset *wbits,
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struct bitset *xbits)
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{
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BOOL read, write, except;
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int i, ret;
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INPUT_RECORD *irbuffer;
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DWORD avail, nbuffer;
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BOOL bRet;
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IO_STATUS_BLOCK iosb;
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FILE_PIPE_LOCAL_INFORMATION fpli;
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static PNtQueryInformationFile NtQueryInformationFile;
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static BOOL once_only;
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read = write = except = FALSE;
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switch (GetFileType (h))
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{
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case FILE_TYPE_DISK:
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read = TRUE;
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write = TRUE;
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break;
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case FILE_TYPE_PIPE:
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if (!once_only)
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{
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NtQueryInformationFile = (PNtQueryInformationFile)
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GetProcAddress (GetModuleHandle ("ntdll.dll"),
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"NtQueryInformationFile");
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once_only = TRUE;
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}
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if (PeekNamedPipe (h, NULL, 0, NULL, &avail, NULL) != 0)
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{
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if (avail)
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read = TRUE;
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}
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else if (GetLastError () == ERROR_BROKEN_PIPE)
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;
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else
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{
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/* It was the write-end of the pipe. Check if it is writable.
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If NtQueryInformationFile fails, optimistically assume the pipe is
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writable. This could happen on Windows 9x, where
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NtQueryInformationFile is not available, or if we inherit a pipe
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that doesn't permit FILE_READ_ATTRIBUTES access on the write end
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(I think this should not happen since Windows XP SP2; WINE seems
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fine too). Otherwise, ensure that enough space is available for
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atomic writes. */
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memset (&iosb, 0, sizeof (iosb));
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memset (&fpli, 0, sizeof (fpli));
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if (!NtQueryInformationFile
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|| NtQueryInformationFile (h, &iosb, &fpli, sizeof (fpli),
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FilePipeLocalInformation)
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|| fpli.WriteQuotaAvailable >= PIPE_BUF
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|| (fpli.OutboundQuota < PIPE_BUF &&
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fpli.WriteQuotaAvailable == fpli.OutboundQuota))
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write = TRUE;
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}
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break;
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case FILE_TYPE_CHAR:
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write = TRUE;
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if (!(rbits->in[fd / CHAR_BIT] & (1 << (fd & (CHAR_BIT - 1)))))
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break;
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ret = WaitForSingleObject (h, 0);
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if (ret == WAIT_OBJECT_0)
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{
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if (!IsConsoleHandle (h))
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{
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read = TRUE;
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break;
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}
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nbuffer = avail = 0;
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bRet = GetNumberOfConsoleInputEvents (h, &nbuffer);
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/* Screen buffers handles are filtered earlier. */
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assert (bRet);
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if (nbuffer == 0)
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{
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except = TRUE;
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break;
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}
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irbuffer = (INPUT_RECORD *) alloca (nbuffer * sizeof (INPUT_RECORD));
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bRet = PeekConsoleInput (h, irbuffer, nbuffer, &avail);
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if (!bRet || avail == 0)
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{
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except = TRUE;
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break;
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}
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for (i = 0; i < avail; i++)
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if (irbuffer[i].EventType == KEY_EVENT)
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read = TRUE;
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}
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break;
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default:
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ret = WaitForSingleObject (h, 0);
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write = TRUE;
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if (ret == WAIT_OBJECT_0)
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read = TRUE;
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break;
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}
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ret = 0;
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if (read && (rbits->in[fd / CHAR_BIT] & (1 << (fd & (CHAR_BIT - 1)))))
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{
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rbits->out[fd / CHAR_BIT] |= (1 << (fd & (CHAR_BIT - 1)));
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ret++;
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}
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if (write && (wbits->in[fd / CHAR_BIT] & (1 << (fd & (CHAR_BIT - 1)))))
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{
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wbits->out[fd / CHAR_BIT] |= (1 << (fd & (CHAR_BIT - 1)));
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ret++;
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}
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if (except && (xbits->in[fd / CHAR_BIT] & (1 << (fd & (CHAR_BIT - 1)))))
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{
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xbits->out[fd / CHAR_BIT] |= (1 << (fd & (CHAR_BIT - 1)));
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ret++;
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}
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return ret;
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}
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int
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rpl_select (int nfds, fd_set *rfds, fd_set *wfds, fd_set *xfds,
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struct timeval *timeout)
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#undef timeval
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{
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static struct timeval tv0;
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static HANDLE hEvent;
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HANDLE h, handle_array[FD_SETSIZE + 2];
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fd_set handle_rfds, handle_wfds, handle_xfds;
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struct bitset rbits, wbits, xbits;
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unsigned char anyfds_in[FD_SETSIZE / CHAR_BIT];
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DWORD ret, wait_timeout, nhandles, nsock, nbuffer;
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MSG msg;
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int i, fd, rc;
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clock_t tend;
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if (nfds > FD_SETSIZE)
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nfds = FD_SETSIZE;
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if (!timeout)
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wait_timeout = INFINITE;
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else
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{
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wait_timeout = timeout->tv_sec * 1000 + timeout->tv_usec / 1000;
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/* select is also used as a portable usleep. */
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if (!rfds && !wfds && !xfds)
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{
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Sleep (wait_timeout);
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return 0;
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}
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}
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if (!hEvent)
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hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);
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handle_array[0] = hEvent;
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nhandles = 1;
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nsock = 0;
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/* Copy descriptors to bitsets. At the same time, eliminate
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bits in the "wrong" direction for console input buffers
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and screen buffers, because screen buffers are waitable
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and they will block until a character is available. */
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memset (&rbits, 0, sizeof (rbits));
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memset (&wbits, 0, sizeof (wbits));
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memset (&xbits, 0, sizeof (xbits));
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memset (anyfds_in, 0, sizeof (anyfds_in));
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if (rfds)
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for (i = 0; i < rfds->fd_count; i++)
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{
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fd = rfds->fd_array[i];
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h = (HANDLE) _get_osfhandle (fd);
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if (IsConsoleHandle (h)
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&& !GetNumberOfConsoleInputEvents (h, &nbuffer))
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continue;
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rbits.in[fd / CHAR_BIT] |= 1 << (fd & (CHAR_BIT - 1));
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anyfds_in[fd / CHAR_BIT] |= 1 << (fd & (CHAR_BIT - 1));
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}
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else
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rfds = (fd_set *) alloca (sizeof (fd_set));
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if (wfds)
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for (i = 0; i < wfds->fd_count; i++)
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{
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fd = wfds->fd_array[i];
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h = (HANDLE) _get_osfhandle (fd);
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if (IsConsoleHandle (h)
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&& GetNumberOfConsoleInputEvents (h, &nbuffer))
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continue;
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wbits.in[fd / CHAR_BIT] |= 1 << (fd & (CHAR_BIT - 1));
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anyfds_in[fd / CHAR_BIT] |= 1 << (fd & (CHAR_BIT - 1));
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}
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else
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wfds = (fd_set *) alloca (sizeof (fd_set));
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if (xfds)
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for (i = 0; i < xfds->fd_count; i++)
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{
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fd = xfds->fd_array[i];
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xbits.in[fd / CHAR_BIT] |= 1 << (fd & (CHAR_BIT - 1));
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anyfds_in[fd / CHAR_BIT] |= 1 << (fd & (CHAR_BIT - 1));
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}
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else
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xfds = (fd_set *) alloca (sizeof (fd_set));
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/* Zero all the fd_sets, including the application's. */
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FD_ZERO (rfds);
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FD_ZERO (wfds);
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FD_ZERO (xfds);
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FD_ZERO (&handle_rfds);
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FD_ZERO (&handle_wfds);
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FD_ZERO (&handle_xfds);
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/* Classify handles. Create fd sets for sockets, poll the others. */
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for (i = 0; i < nfds; i++)
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{
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if ((anyfds_in[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1)))) == 0)
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continue;
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h = (HANDLE) _get_osfhandle (i);
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if (!h)
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{
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errno = EBADF;
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return -1;
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}
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if (IsSocketHandle (h))
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{
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int requested = FD_CLOSE;
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/* See above; socket handles are mapped onto select, but we
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need to map descriptors to handles. */
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if (rbits.in[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1))))
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{
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requested |= FD_READ | FD_ACCEPT;
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FD_SET ((SOCKET) h, rfds);
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FD_SET ((SOCKET) h, &handle_rfds);
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}
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if (wbits.in[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1))))
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{
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requested |= FD_WRITE | FD_CONNECT;
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FD_SET ((SOCKET) h, wfds);
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FD_SET ((SOCKET) h, &handle_wfds);
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}
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if (xbits.in[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1))))
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{
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requested |= FD_OOB;
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FD_SET ((SOCKET) h, xfds);
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FD_SET ((SOCKET) h, &handle_xfds);
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}
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WSAEventSelect ((SOCKET) h, hEvent, requested);
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nsock++;
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}
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else
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{
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handle_array[nhandles++] = h;
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/* Poll now. If we get an event, do not wait below. */
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if (wait_timeout != 0
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&& windows_poll_handle (h, i, &rbits, &wbits, &xbits))
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wait_timeout = 0;
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}
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}
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/* Place a sentinel at the end of the array. */
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handle_array[nhandles] = NULL;
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/* When will the waiting period expire? */
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if (wait_timeout != INFINITE)
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tend = clock () + wait_timeout;
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restart:
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if (wait_timeout == 0 || nsock == 0)
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rc = 0;
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else
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{
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/* See if we need to wait in the loop below. If any select is ready,
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do MsgWaitForMultipleObjects anyway to dispatch messages, but
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no need to call select again. */
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rc = select (0, &handle_rfds, &handle_wfds, &handle_xfds, &tv0);
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if (rc == 0)
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{
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/* Restore the fd_sets for the other select we do below. */
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memcpy (&handle_rfds, rfds, sizeof (fd_set));
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memcpy (&handle_wfds, wfds, sizeof (fd_set));
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memcpy (&handle_xfds, xfds, sizeof (fd_set));
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}
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else
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wait_timeout = 0;
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}
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/* How much is left to wait? */
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if (wait_timeout != INFINITE)
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{
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clock_t tnow = clock ();
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if (tend >= tnow)
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wait_timeout = tend - tnow;
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else
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wait_timeout = 0;
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}
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for (;;)
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{
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ret = MsgWaitForMultipleObjects (nhandles, handle_array, FALSE,
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wait_timeout, QS_ALLINPUT);
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|
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if (ret == WAIT_OBJECT_0 + nhandles)
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{
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/* new input of some other kind */
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BOOL bRet;
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while ((bRet = PeekMessage (&msg, NULL, 0, 0, PM_REMOVE)) != 0)
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{
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TranslateMessage (&msg);
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DispatchMessage (&msg);
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}
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}
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else
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break;
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}
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/* If we haven't done it yet, check the status of the sockets. */
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if (rc == 0 && nsock > 0)
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rc = select (0, &handle_rfds, &handle_wfds, &handle_xfds, &tv0);
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|
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if (nhandles > 1)
|
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{
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/* Count results that are not counted in the return value of select. */
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nhandles = 1;
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for (i = 0; i < nfds; i++)
|
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{
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if ((anyfds_in[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1)))) == 0)
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continue;
|
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|
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h = (HANDLE) _get_osfhandle (i);
|
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if (h == handle_array[nhandles])
|
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{
|
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/* Not a socket. */
|
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nhandles++;
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windows_poll_handle (h, i, &rbits, &wbits, &xbits);
|
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if (rbits.out[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1)))
|
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|| wbits.out[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1)))
|
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|| xbits.out[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1))))
|
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rc++;
|
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}
|
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}
|
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|
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if (rc == 0
|
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&& (wait_timeout == INFINITE
|
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/* If NHANDLES > 1, but no bits are set, it means we've
|
|
been told incorrectly that some handle was signaled.
|
|
This happens with anonymous pipes, which always cause
|
|
MsgWaitForMultipleObjects to exit immediately, but no
|
|
data is found ready to be read by windows_poll_handle.
|
|
To avoid a total failure (whereby we return zero and
|
|
don't wait at all), let's poll in a more busy loop. */
|
|
|| (wait_timeout != 0 && nhandles > 1)))
|
|
{
|
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/* Sleep 1 millisecond to avoid busy wait and retry with the
|
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original fd_sets. */
|
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memcpy (&handle_rfds, rfds, sizeof (fd_set));
|
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memcpy (&handle_wfds, wfds, sizeof (fd_set));
|
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memcpy (&handle_xfds, xfds, sizeof (fd_set));
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SleepEx (1, TRUE);
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goto restart;
|
|
}
|
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if (timeout && wait_timeout == 0 && rc == 0)
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timeout->tv_sec = timeout->tv_usec = 0;
|
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}
|
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|
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/* Now fill in the results. */
|
|
FD_ZERO (rfds);
|
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FD_ZERO (wfds);
|
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FD_ZERO (xfds);
|
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nhandles = 1;
|
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for (i = 0; i < nfds; i++)
|
|
{
|
|
if ((anyfds_in[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1)))) == 0)
|
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continue;
|
|
|
|
h = (HANDLE) _get_osfhandle (i);
|
|
if (h != handle_array[nhandles])
|
|
{
|
|
/* Perform handle->descriptor mapping. */
|
|
WSAEventSelect ((SOCKET) h, NULL, 0);
|
|
if (FD_ISSET (h, &handle_rfds))
|
|
FD_SET (i, rfds);
|
|
if (FD_ISSET (h, &handle_wfds))
|
|
FD_SET (i, wfds);
|
|
if (FD_ISSET (h, &handle_xfds))
|
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FD_SET (i, xfds);
|
|
}
|
|
else
|
|
{
|
|
/* Not a socket. */
|
|
nhandles++;
|
|
if (rbits.out[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1))))
|
|
FD_SET (i, rfds);
|
|
if (wbits.out[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1))))
|
|
FD_SET (i, wfds);
|
|
if (xbits.out[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1))))
|
|
FD_SET (i, xfds);
|
|
}
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
#else /* ! Native Windows. */
|
|
|
|
#include <sys/select.h>
|
|
#include <stddef.h> /* NULL */
|
|
#include <errno.h>
|
|
#include <unistd.h>
|
|
|
|
#undef select
|
|
|
|
int
|
|
rpl_select (int nfds, fd_set *rfds, fd_set *wfds, fd_set *xfds,
|
|
struct timeval *timeout)
|
|
{
|
|
int i;
|
|
|
|
/* FreeBSD 8.2 has a bug: it does not always detect invalid fds. */
|
|
if (nfds < 0 || nfds > FD_SETSIZE)
|
|
{
|
|
errno = EINVAL;
|
|
return -1;
|
|
}
|
|
for (i = 0; i < nfds; i++)
|
|
{
|
|
if (((rfds && FD_ISSET (i, rfds))
|
|
|| (wfds && FD_ISSET (i, wfds))
|
|
|| (xfds && FD_ISSET (i, xfds)))
|
|
&& dup2 (i, i) != i)
|
|
return -1;
|
|
}
|
|
|
|
/* Interix 3.5 has a bug: it does not support nfds == 0. */
|
|
if (nfds == 0)
|
|
{
|
|
nfds = 1;
|
|
rfds = NULL;
|
|
wfds = NULL;
|
|
xfds = NULL;
|
|
}
|
|
return select (nfds, rfds, wfds, xfds, timeout);
|
|
}
|
|
|
|
#endif
|