1 files changed, 656 insertions, 0 deletions

diff --git a/win32/poll.c b/win32/poll.c
new file mode 100644
index 000000000..8ab6bbf29
--- /dev/null
+++ b/win32/poll.c
@@ -0,0 +1,656 @@
+/* Emulation for poll(2)
+   Contributed by Paolo Bonzini.
+
+   Copyright 2001-2003, 2006-2024 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/>.  */
+
+/* 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 "libbb.h"
+#include <malloc.h>
+
+#include <sys/types.h>
+
+/* Specification.  */
+#include <poll.h>
+
+#include <errno.h>
+#include <limits.h>
+#include <assert.h>
+
+#if defined _WIN32 && ! defined __CYGWIN__
+# define WINDOWS_NATIVE
+# include <winsock2.h>
+# include <windows.h>
+# include <io.h>
+# include <stdio.h>
+# include <conio.h>
+#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>
+
+#ifndef INFTIM
+# define INFTIM (-1)
+#endif
+
+/* BeOS does not have MSG_PEEK.  */
+#ifndef MSG_PEEK
+# define MSG_PEEK 0
+#endif
+
+#ifdef WINDOWS_NATIVE
+
+/* 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
+
+/* Do *not* use the function WSAPoll
+   <https://docs.microsoft.com/en-us/windows/desktop/api/winsock2/nf-winsock2-wsapoll>
+   because there is a bug named “Windows 8 Bugs 309411 - WSAPoll does not
+   report failed connections” that Microsoft won't fix.
+   See Daniel Stenberg: "WASPoll is broken"
+   <https://daniel.haxx.se/blog/2012/10/10/wsapoll-is-broken/>.  */
+
+/* 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
+
+/* Here we need timeval from Windows since this is what the select() function
+   from Windows requires.  */
+# undef timeval
+
+/* Avoid warnings from gcc -Wcast-function-type.  */
+# define GetProcAddress \
+   (void *) GetProcAddress
+
+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;
+#if 0
+  IO_STATUS_BLOCK iosb;
+  FILE_PIPE_LOCAL_INFORMATION fpli;
+  static PNtQueryInformationFile NtQueryInformationFile;
+  static BOOL once_only;
+#endif
+
+  switch (GetFileType (h))
+    {
+    case FILE_TYPE_PIPE:
+#if 0
+      if (!once_only)
+        {
+          NtQueryInformationFile = (PNtQueryInformationFile)
+            GetProcAddress (GetModuleHandle ("ntdll.dll"),
+                            "NtQueryInformationFile");
+          once_only = TRUE;
+        }
+#endif
+
+      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
+        {
+                /* The writability of a pipe can't be detected reliably on Windows.
+                 * Just say it's OK.
+                 *
+                 * Details:
+                 *
+                 *    https://github.com/git-for-windows/git/commit/94f4d01932279c419844aa708bec31a26056bc6b
+                 */
+#if 0
+          /* 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))
+#endif
+            happened |= *p_sought & (POLLOUT | POLLWRNORM | POLLWRBAND);
+        }
+      return happened;
+
+    case FILE_TYPE_CHAR:
+      // Fall through to default case for non-console, e.g. /dev/null.
+      if (IsConsoleHandle (h)) {
+      nbuffer = avail = 0;
+      bRet = GetNumberOfConsoleInputEvents (h, &nbuffer);
+      if (bRet)
+        {
+          /* Input buffer.  */
+          *p_sought &= POLLIN | POLLRDNORM;
+          if (nbuffer == 0)
+            // Having no unread events isn't an error condition.
+            return 0 /* was POLLHUP */;
+          if (!*p_sought)
+            return 0;
+
+          irbuffer = (INPUT_RECORD *) alloca (nbuffer * sizeof (INPUT_RECORD));
+          bRet = PeekConsoleInputW (h, irbuffer, nbuffer, &avail);
+          if (!bRet || avail == 0)
+            return POLLHUP;
+
+          for (i = 0; i < avail; i++)
+            // Ignore key release.
+            if (irbuffer[i].EventType == KEY_EVENT &&
+                irbuffer[i].Event.KeyEvent.bKeyDown)
+              return *p_sought;
+          return 0;
+        }
+      else
+        {
+          /* Screen buffer.  */
+          *p_sought &= POLLOUT | POLLWRNORM | POLLWRBAND;
+          return *p_sought;
+        }
+      }
+      /* fall through */
+
+    default:
+      ret = WaitForSingleObject (h, 0);
+      if (ret == WAIT_OBJECT_0)
+        return *p_sought & ~(POLLPRI | POLLRDBAND);
+
+      // Add (POLLIN | POLLRDNORM).  Why only support write?
+      return *p_sought & (POLLIN | POLLRDNORM | 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;
+      tv = (struct timeval) {0};
+    }
+  else if (timeout > 0)
+    {
+      ptv = &tv;
+      tv = (struct timeval) {
+        .tv_sec = timeout / 1000,
+        .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;
+  DWORD real_timeout = 0;
+  int save_timeout = timeout;
+  clock_t tend = clock () + timeout;
+
+  if (nfd > INT_MAX || timeout < -1)
+    {
+      errno = EINVAL;
+      return -1;
+    }
+
+  if (!hEvent)
+    hEvent = CreateEvent (NULL, FALSE, FALSE, NULL);
+
+restart:
+  /* How much is left to wait? */
+  timeout = save_timeout;
+  if (timeout != INFTIM)
+    {
+      clock_t now = clock ();
+      real_timeout = tend > now ? tend - now : 0;
+    }
+
+  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.  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 && (save_timeout == INFTIM || (real_timeout != 0 && nhandles > 1)))
+    {
+      SleepEx (1, TRUE);
+      goto restart;
+    }
+
+  return rc;
+#endif
+}