diff options
Diffstat (limited to 'lib/select.c')
| -rw-r--r-- | lib/select.c | 598 |
1 files changed, 598 insertions, 0 deletions
diff --git a/lib/select.c b/lib/select.c new file mode 100644 index 0000000..c242498 --- /dev/null +++ b/lib/select.c @@ -0,0 +1,598 @@ +/* Emulation for select(2) + Contributed by Paolo Bonzini. + + Copyright 2008-2022 Free Software Foundation, Inc. + + This file is part of gnulib. + + This file is free software: you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + This file 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 Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +#include <config.h> + +/* Specification. */ +#include <sys/select.h> + +#if defined _WIN32 && ! defined __CYGWIN__ +/* Native Windows. */ + +#include <alloca.h> +#include <assert.h> +#include <sys/types.h> +#include <errno.h> +#include <limits.h> + +#include <winsock2.h> +#include <windows.h> +#include <io.h> +#include <stdio.h> +#include <conio.h> +#include <time.h> + +/* Get the overridden 'struct timeval'. */ +#include <sys/time.h> + +#if GNULIB_MSVC_NOTHROW +# include "msvc-nothrow.h" +#else +# include <io.h> +#endif + +#undef select + +/* Don't assume that UNICODE is not defined. */ +#undef GetModuleHandle +#define GetModuleHandle GetModuleHandleA +#undef PeekConsoleInput +#define PeekConsoleInput PeekConsoleInputA +#undef CreateEvent +#define CreateEvent CreateEventA +#undef PeekMessage +#define PeekMessage PeekMessageA +#undef DispatchMessage +#define DispatchMessage DispatchMessageA + +/* Avoid warnings from gcc -Wcast-function-type. */ +#define GetProcAddress \ + (void *) GetProcAddress + +struct bitset { + unsigned char in[FD_SETSIZE / CHAR_BIT]; + unsigned char out[FD_SETSIZE / CHAR_BIT]; +}; + +/* 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 + +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; +} + +/* Compute output fd_sets for libc descriptor FD (whose Windows handle is + H). */ + +static int +windows_poll_handle (HANDLE h, int fd, + struct bitset *rbits, + struct bitset *wbits, + struct bitset *xbits) +{ + BOOL read, write, except; + int i, ret; + INPUT_RECORD *irbuffer; + DWORD avail, nbuffer; + BOOL bRet; + IO_STATUS_BLOCK iosb; + FILE_PIPE_LOCAL_INFORMATION fpli; + static PNtQueryInformationFile NtQueryInformationFile; + static BOOL once_only; + + read = write = except = FALSE; + switch (GetFileType (h)) + { + case FILE_TYPE_DISK: + read = TRUE; + write = TRUE; + break; + + case FILE_TYPE_PIPE: + if (!once_only) + { + NtQueryInformationFile = (PNtQueryInformationFile) + GetProcAddress (GetModuleHandle ("ntdll.dll"), + "NtQueryInformationFile"); + once_only = TRUE; + } + + if (PeekNamedPipe (h, NULL, 0, NULL, &avail, NULL) != 0) + { + if (avail) + read = TRUE; + } + else if (GetLastError () == ERROR_BROKEN_PIPE) + ; + + 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)) + write = TRUE; + } + break; + + case FILE_TYPE_CHAR: + write = TRUE; + if (!(rbits->in[fd / CHAR_BIT] & (1 << (fd & (CHAR_BIT - 1))))) + break; + + ret = WaitForSingleObject (h, 0); + if (ret == WAIT_OBJECT_0) + { + if (!IsConsoleHandle (h)) + { + read = TRUE; + break; + } + + nbuffer = avail = 0; + bRet = GetNumberOfConsoleInputEvents (h, &nbuffer); + + /* Screen buffers handles are filtered earlier. */ + assert (bRet); + if (nbuffer == 0) + { + except = TRUE; + break; + } + + irbuffer = (INPUT_RECORD *) alloca (nbuffer * sizeof (INPUT_RECORD)); + bRet = PeekConsoleInput (h, irbuffer, nbuffer, &avail); + if (!bRet || avail == 0) + { + except = TRUE; + break; + } + + for (i = 0; i < avail; i++) + if (irbuffer[i].EventType == KEY_EVENT) + read = TRUE; + } + break; + + default: + ret = WaitForSingleObject (h, 0); + write = TRUE; + if (ret == WAIT_OBJECT_0) + read = TRUE; + + break; + } + + ret = 0; + if (read && (rbits->in[fd / CHAR_BIT] & (1 << (fd & (CHAR_BIT - 1))))) + { + rbits->out[fd / CHAR_BIT] |= (1 << (fd & (CHAR_BIT - 1))); + ret++; + } + + if (write && (wbits->in[fd / CHAR_BIT] & (1 << (fd & (CHAR_BIT - 1))))) + { + wbits->out[fd / CHAR_BIT] |= (1 << (fd & (CHAR_BIT - 1))); + ret++; + } + + if (except && (xbits->in[fd / CHAR_BIT] & (1 << (fd & (CHAR_BIT - 1))))) + { + xbits->out[fd / CHAR_BIT] |= (1 << (fd & (CHAR_BIT - 1))); + ret++; + } + + return ret; +} + +int +rpl_select (int nfds, fd_set *rfds, fd_set *wfds, fd_set *xfds, + struct timeval *timeout) +#undef timeval +{ + static struct timeval tv0; + static HANDLE hEvent; + HANDLE h, handle_array[FD_SETSIZE + 2]; + fd_set handle_rfds, handle_wfds, handle_xfds; + struct bitset rbits, wbits, xbits; + unsigned char anyfds_in[FD_SETSIZE / CHAR_BIT]; + DWORD ret, wait_timeout, nhandles, nsock, nbuffer; + MSG msg; + int i, fd, rc; + clock_t tend; + + if (nfds > FD_SETSIZE) + nfds = FD_SETSIZE; + + if (!timeout) + wait_timeout = INFINITE; + else + { + wait_timeout = timeout->tv_sec * 1000 + timeout->tv_usec / 1000; + + /* select is also used as a portable usleep. */ + if (!rfds && !wfds && !xfds) + { + Sleep (wait_timeout); + return 0; + } + } + + if (!hEvent) + hEvent = CreateEvent (NULL, FALSE, FALSE, NULL); + + handle_array[0] = hEvent; + nhandles = 1; + nsock = 0; + + /* Copy descriptors to bitsets. At the same time, eliminate + bits in the "wrong" direction for console input buffers + and screen buffers, because screen buffers are waitable + and they will block until a character is available. */ + memset (&rbits, 0, sizeof (rbits)); + memset (&wbits, 0, sizeof (wbits)); + memset (&xbits, 0, sizeof (xbits)); + memset (anyfds_in, 0, sizeof (anyfds_in)); + if (rfds) + for (i = 0; i < rfds->fd_count; i++) + { + fd = rfds->fd_array[i]; + h = (HANDLE) _get_osfhandle (fd); + if (IsConsoleHandle (h) + && !GetNumberOfConsoleInputEvents (h, &nbuffer)) + continue; + + rbits.in[fd / CHAR_BIT] |= 1 << (fd & (CHAR_BIT - 1)); + anyfds_in[fd / CHAR_BIT] |= 1 << (fd & (CHAR_BIT - 1)); + } + else + rfds = (fd_set *) alloca (sizeof (fd_set)); + + if (wfds) + for (i = 0; i < wfds->fd_count; i++) + { + fd = wfds->fd_array[i]; + h = (HANDLE) _get_osfhandle (fd); + if (IsConsoleHandle (h) + && GetNumberOfConsoleInputEvents (h, &nbuffer)) + continue; + + wbits.in[fd / CHAR_BIT] |= 1 << (fd & (CHAR_BIT - 1)); + anyfds_in[fd / CHAR_BIT] |= 1 << (fd & (CHAR_BIT - 1)); + } + else + wfds = (fd_set *) alloca (sizeof (fd_set)); + + if (xfds) + for (i = 0; i < xfds->fd_count; i++) + { + fd = xfds->fd_array[i]; + xbits.in[fd / CHAR_BIT] |= 1 << (fd & (CHAR_BIT - 1)); + anyfds_in[fd / CHAR_BIT] |= 1 << (fd & (CHAR_BIT - 1)); + } + else + xfds = (fd_set *) alloca (sizeof (fd_set)); + + /* Zero all the fd_sets, including the application's. */ + FD_ZERO (rfds); + FD_ZERO (wfds); + FD_ZERO (xfds); + FD_ZERO (&handle_rfds); + FD_ZERO (&handle_wfds); + FD_ZERO (&handle_xfds); + + /* Classify handles. Create fd sets for sockets, poll the others. */ + for (i = 0; i < nfds; i++) + { + if ((anyfds_in[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1)))) == 0) + continue; + + h = (HANDLE) _get_osfhandle (i); + if (!h) + { + errno = EBADF; + return -1; + } + + if (IsSocketHandle (h)) + { + int requested = FD_CLOSE; + + /* See above; socket handles are mapped onto select, but we + need to map descriptors to handles. */ + if (rbits.in[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1)))) + { + requested |= FD_READ | FD_ACCEPT; + FD_SET ((SOCKET) h, rfds); + FD_SET ((SOCKET) h, &handle_rfds); + } + if (wbits.in[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1)))) + { + requested |= FD_WRITE | FD_CONNECT; + FD_SET ((SOCKET) h, wfds); + FD_SET ((SOCKET) h, &handle_wfds); + } + if (xbits.in[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1)))) + { + requested |= FD_OOB; + FD_SET ((SOCKET) h, xfds); + FD_SET ((SOCKET) h, &handle_xfds); + } + + WSAEventSelect ((SOCKET) h, hEvent, requested); + nsock++; + } + else + { + handle_array[nhandles++] = h; + + /* Poll now. If we get an event, do not wait below. */ + if (wait_timeout != 0 + && windows_poll_handle (h, i, &rbits, &wbits, &xbits)) + wait_timeout = 0; + } + } + + /* Place a sentinel at the end of the array. */ + handle_array[nhandles] = NULL; + + /* When will the waiting period expire? */ + if (wait_timeout != INFINITE) + tend = clock () + wait_timeout; + +restart: + if (wait_timeout == 0 || nsock == 0) + rc = 0; + else + { + /* See if we need to wait in the loop below. If any select is ready, + do MsgWaitForMultipleObjects anyway to dispatch messages, but + no need to call select again. */ + rc = select (0, &handle_rfds, &handle_wfds, &handle_xfds, &tv0); + if (rc == 0) + { + /* Restore the fd_sets for the other select we do below. */ + memcpy (&handle_rfds, rfds, sizeof (fd_set)); + memcpy (&handle_wfds, wfds, sizeof (fd_set)); + memcpy (&handle_xfds, xfds, sizeof (fd_set)); + } + else + wait_timeout = 0; + } + + /* How much is left to wait? */ + if (wait_timeout != INFINITE) + { + clock_t tnow = clock (); + if (tend >= tnow) + wait_timeout = tend - tnow; + else + wait_timeout = 0; + } + + 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 we haven't done it yet, check the status of the sockets. */ + if (rc == 0 && nsock > 0) + rc = select (0, &handle_rfds, &handle_wfds, &handle_xfds, &tv0); + + if (nhandles > 1) + { + /* Count results that are not counted in the return value of select. */ + nhandles = 1; + for (i = 0; i < nfds; i++) + { + if ((anyfds_in[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1)))) == 0) + continue; + + h = (HANDLE) _get_osfhandle (i); + if (h == handle_array[nhandles]) + { + /* Not a socket. */ + nhandles++; + windows_poll_handle (h, i, &rbits, &wbits, &xbits); + if (rbits.out[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1))) + || wbits.out[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1))) + || xbits.out[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1)))) + rc++; + } + } + + if (rc == 0 + && (wait_timeout == INFINITE + /* 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))) + { + /* Sleep 1 millisecond to avoid busy wait and retry with the + original fd_sets. */ + memcpy (&handle_rfds, rfds, sizeof (fd_set)); + memcpy (&handle_wfds, wfds, sizeof (fd_set)); + memcpy (&handle_xfds, xfds, sizeof (fd_set)); + SleepEx (1, TRUE); + goto restart; + } + if (timeout && wait_timeout == 0 && rc == 0) + timeout->tv_sec = timeout->tv_usec = 0; + } + + /* Now fill in the results. */ + FD_ZERO (rfds); + FD_ZERO (wfds); + FD_ZERO (xfds); + nhandles = 1; + for (i = 0; i < nfds; i++) + { + if ((anyfds_in[i / CHAR_BIT] & (1 << (i & (CHAR_BIT - 1)))) == 0) + continue; + + h = (HANDLE) _get_osfhandle (i); + if (h != handle_array[nhandles]) + { + /* Perform handle->descriptor mapping. */ + SOCKET s = (SOCKET) h; + WSAEventSelect (s, NULL, 0); + if (FD_ISSET (s, &handle_rfds)) + FD_SET (i, rfds); + if (FD_ISSET (s, &handle_wfds)) + FD_SET (i, wfds); + if (FD_ISSET (s, &handle_xfds)) + 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 <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 |