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git/compat/poll/poll.c

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/* Emulation for poll(2)
Contributed by Paolo Bonzini.
Copyright 2001-2003, 2006-2011 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 2, 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 <http://www.gnu.org/licenses/>. */
/* To bump the minimum Windows version to Windows Vista */
#include "git-compat-util.h"
/* 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
#if defined(WIN32)
# include <malloc.h>
#endif
#include <sys/types.h>
#include <errno.h>
#include <limits.h>
#include <assert.h>
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
# define WIN32_NATIVE
# if defined (_MSC_VER) && !defined(_WIN32_WINNT)
# define _WIN32_WINNT 0x0502
# endif
# include <winsock2.h>
# include <windows.h>
# include <io.h>
# include <stdio.h>
# include <conio.h>
#else
# include <sys/time.h>
# include <sys/socket.h>
# ifndef NO_SYS_SELECT_H
# include <sys/select.h>
# endif
# include <unistd.h>
#endif
/* Specification. */
#include "poll.h"
#ifdef HAVE_SYS_IOCTL_H
# include <sys/ioctl.h>
#endif
#ifdef HAVE_SYS_FILIO_H
# include <sys/filio.h>
#endif
#include <time.h>
#ifndef INFTIM
# define INFTIM (-1)
#endif
/* BeOS does not have MSG_PEEK. */
#ifndef MSG_PEEK
# define MSG_PEEK 0
#endif
#ifdef WIN32_NATIVE
#define IsConsoleHandle(h) (((long) (intptr_t) (h) & 3) == 3)
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
win32_compute_revents (HANDLE h, int *p_sought)
{
int i, ret, happened;
INPUT_RECORD *irbuffer;
DWORD avail, nbuffer;
BOOL bRet;
switch (GetFileType (h))
{
case FILE_TYPE_PIPE:
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. Unfortunately there is no
reliable way of knowing if it can be written without blocking.
Just say that it's all good. */
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
win32_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 (/* (r == -1) && */ 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 WIN32_NATIVE
fd_set rfds, wfds, efds;
struct timeval tv;
struct timeval *ptv;
int maxfd, rc;
nfds_t i;
# ifdef _SC_OPEN_MAX
static int sc_open_max = -1;
if (nfd < 0
|| (nfd > sc_open_max
&& (sc_open_max != -1
|| nfd > (sc_open_max = sysconf (_SC_OPEN_MAX)))))
{
errno = EINVAL;
return -1;
}
# else /* !_SC_OPEN_MAX */
# ifdef OPEN_MAX
if (nfd < 0 || nfd > OPEN_MAX)
{
errno = EINVAL;
return -1;
}
# endif /* OPEN_MAX -- else, no check is needed */
# endif /* !_SC_OPEN_MAX */
/* 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 (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);
if (pfd[i].fd >= maxfd
&& (pfd[i].events & (POLLIN | POLLOUT | POLLPRI
| POLLRDNORM | POLLRDBAND
| POLLWRNORM | POLLWRBAND)))
{
maxfd = pfd[i].fd;
if (maxfd > FD_SETSIZE)
{
errno = EOVERFLOW;
return -1;
}
}
}
/* 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++)
if (pfd[i].fd < 0)
pfd[i].revents = 0;
else
{
int happened = compute_revents (pfd[i].fd, pfd[i].events,
&rfds, &wfds, &efds);
if (happened)
{
pfd[i].revents = happened;
rc++;
}
else
{
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, orig_timeout = 0;
ULONGLONG start = 0;
fd_set rfds, wfds, xfds;
BOOL poll_again;
MSG msg;
int rc = 0;
nfds_t i;
if (nfd < 0 || timeout < -1)
{
errno = EINVAL;
return -1;
}
if (timeout != INFTIM)
{
orig_timeout = timeout;
start = GetTickCount64();
}
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);
assert (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. win32_compute_revents eliminates
bits for the "wrong" direction. */
pfd[i].revents = win32_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, NULL, 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 = win32_compute_revents_socket ((SOCKET) h, pfd[i].events,
ev.lNetworkEvents);
}
else
{
/* Not a socket. */
int sought = pfd[i].events;
happened = win32_compute_revents (h, &sought);
nhandles++;
}
if ((pfd[i].revents |= happened) != 0)
rc++;
}
if (!rc && orig_timeout && timeout != INFTIM)
{
ULONGLONG elapsed = GetTickCount64() - start;
timeout = elapsed >= orig_timeout ? 0 : (int)(orig_timeout - elapsed);
}
if (!rc && timeout)
{
SleepEx (1, TRUE);
goto restart;
}
return rc;
#endif
}
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