dtable.cc

cygwin, 著名的在win32下模拟unix操作系统的东东

/* dtable.cc: file descriptor support.

   Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

This file is part of Cygwin.

This software is a copyrighted work licensed under the terms of the
Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
details. */

#define  __INSIDE_CYGWIN_NET__

#include "winsup.h"
#include <errno.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/cygwin.h>
#include <assert.h>
#include <ntdef.h>
#include <winnls.h>

#define USE_SYS_TYPES_FD_SET
#include <winsock.h>
#include "pinfo.h"
#include "cygerrno.h"
#include "perprocess.h"
#include "security.h"
#include "fhandler.h"
#include "path.h"
#include "dtable.h"
#include "cygheap.h"
#include "ntdll.h"

static const NO_COPY DWORD std_consts[] = {STD_INPUT_HANDLE, STD_OUTPUT_HANDLE,
					   STD_ERROR_HANDLE};

static const char *handle_to_fn (HANDLE, char *);

static const char NO_COPY unknown_file[] = "some disk file";

/* Set aside space for the table of fds */
void
dtable_init (void)
{
  if (!cygheap->fdtab.size)
    cygheap->fdtab.extend (NOFILE_INCR);
}

void __stdcall
set_std_handle (int fd)
{
  if (fd == 0)
    SetStdHandle (std_consts[fd], cygheap->fdtab[fd]->get_handle ());
  else if (fd <= 2)
    SetStdHandle (std_consts[fd], cygheap->fdtab[fd]->get_output_handle ());
}

void
dtable::dec_console_fds ()
{
  if (console_fds > 0 && !--console_fds &&
      myself->ctty != TTY_CONSOLE && !check_pty_fds())
    FreeConsole ();
}

int
dtable::extend (int howmuch)
{
  int new_size = size + howmuch;
  fhandler_base **newfds;

  if (howmuch <= 0)
    return 0;

  /* Try to allocate more space for fd table. We can't call realloc ()
     here to preserve old table if memory allocation fails */

  if (!(newfds = (fhandler_base **) ccalloc (HEAP_ARGV, new_size, sizeof newfds[0])))
    {
      debug_printf ("calloc failed");
      return 0;
    }
  if (fds)
    {
      memcpy (newfds, fds, size * sizeof (fds[0]));
      cfree (fds);
    }

  size = new_size;
  fds = newfds;
  debug_printf ("size %d, fds %p", size, fds);
  return 1;
}

void
dtable::get_debugger_info ()
{
  if (being_debugged ())
    {
      char std[3][sizeof ("/dev/ttyNNNN")];
      std[0][0] = std[1][0] = std [2][0] = '\0';
      char buf[sizeof ("cYgstd %x") + 32];
      sprintf (buf, "cYgstd %x %x %x", (unsigned) &std, sizeof (std[0]), 3);
      OutputDebugString (buf);
      for (int i = 0; i < 3; i++)
	if (std[i][0])
	  {
	    path_conv pc;
	    HANDLE h = GetStdHandle (std_consts[i]);
	    fhandler_base *fh = build_fhandler_from_name (i, std[i], NULL, pc);
	    if (!fh)
	      continue;
	    if (!fh->open (&pc, (i ? O_WRONLY : O_RDONLY) | O_BINARY, 0777))
	      release (i);
	    else
	      CloseHandle (h);
	  }
    }
}

/* Initialize the file descriptor/handle mapping table.
   This function should only be called when a cygwin function is invoked
   by a non-cygwin function, i.e., it should only happen very rarely. */

void
dtable::stdio_init ()
{
  extern void set_console_ctty ();
  /* Set these before trying to output anything from strace.
     Also, always set them even if we're to pick up our parent's fds
     in case they're missed.  */

  if (myself->ppid_handle || ISSTATE (myself, PID_CYGPARENT))
    return;

  HANDLE in = GetStdHandle (STD_INPUT_HANDLE);
  HANDLE out = GetStdHandle (STD_OUTPUT_HANDLE);
  HANDLE err = GetStdHandle (STD_ERROR_HANDLE);

  init_std_file_from_handle (0, in);

  /* STD_ERROR_HANDLE has been observed to be the same as
     STD_OUTPUT_HANDLE.  We need separate handles (e.g. using pipes
     to pass data from child to parent).  */
  if (out == err)
    {
      /* Since this code is not invoked for forked tasks, we don't have
	 to worry about the close-on-exec flag here.  */
      if (!DuplicateHandle (hMainProc, out, hMainProc, &err, 0,
			     1, DUPLICATE_SAME_ACCESS))
	{
	  /* If that fails, do this as a fall back.  */
	  err = out;
	  system_printf ("couldn't make stderr distinct from stdout");
	}
    }

  init_std_file_from_handle (1, out);
  init_std_file_from_handle (2, err);
  /* Assign the console as the controlling tty for this process if we actually
     have a console and no other controlling tty has been assigned. */
  if (myself->ctty < 0 && GetConsoleCP () > 0)
    set_console_ctty ();
}

int
dtable::find_unused_handle (int start)
{
  AssertResourceOwner (LOCK_FD_LIST, READ_LOCK);
  do
    {
      for (size_t i = start; i < size; i++)
	/* See if open -- no need for overhead of not_open */
	if (fds[i] == NULL)
	  return i;
    }
  while (extend (NOFILE_INCR));
  return -1;
}

void
dtable::release (int fd)
{
  if (!not_open (fd))
    {
      switch (fds[fd]->get_device ())
	{
	case FH_SOCKET:
	  dec_need_fixup_before ();
	  break;
	case FH_CONSOLE:
	  dec_console_fds ();
	  break;
	}
      delete fds[fd];
      fds[fd] = NULL;
    }
}

extern "C" int
cygwin_attach_handle_to_fd (char *name, int fd, HANDLE handle, mode_t bin,
			    DWORD myaccess)
{
  if (fd == -1)
    fd = cygheap->fdtab.find_unused_handle ();
  path_conv pc;
  fhandler_base *res = cygheap->fdtab.build_fhandler_from_name (fd, name, handle,
								pc);
  res->init (handle, myaccess, bin ?: pc.binmode ());
  return fd;
}

void
dtable::init_std_file_from_handle (int fd, HANDLE handle)
{
  const char *name;
  CONSOLE_SCREEN_BUFFER_INFO buf;
  struct sockaddr sa;
  int sal = sizeof (sa);
  DCB dcb;
  unsigned bin = O_BINARY;

  first_fd_for_open = 0;

  if (!not_open (fd))
    return;

  SetLastError (0);
  DWORD ft = GetFileType (handle);
  if (ft == FILE_TYPE_UNKNOWN && GetLastError () == ERROR_INVALID_HANDLE)
    name = NULL;
  else
    {
      /* See if we can consoleify it */
      if (GetConsoleScreenBufferInfo (handle, &buf))
	{
	  if (ISSTATE (myself, PID_USETTY))
	    name = "/dev/tty";
	  else
	    name = "/dev/conout";
	}
      else if (GetNumberOfConsoleInputEvents (handle, (DWORD *) &buf))
	{
	  if (ISSTATE (myself, PID_USETTY))
	    name = "/dev/tty";
	  else
	    name = "/dev/conin";
	}
      else if (ft == FILE_TYPE_PIPE)
	{
	  if (fd == 0)
	    name = "/dev/piper";
	  else
	    name = "/dev/pipew";
	}
      else if (wsock_started && getpeername ((SOCKET) handle, &sa, &sal) == 0)
	name = "/dev/socket";
      else if (GetCommState (handle, &dcb))
	name = "/dev/ttyS0"; // FIXME - determine correct device
      else
	{
	  name = handle_to_fn (handle, (char *) alloca (MAX_PATH + 100));
	  bin = 0;
	}
    }

  if (!name)
    fds[fd] = NULL;
  else
    {
      path_conv pc;
      fhandler_base *fh = build_fhandler_from_name (fd, name, handle, pc);
      if (!bin)
	{
	  bin = fh->get_default_fmode (O_RDWR);
	  if (!bin && name != unknown_file)
	    bin = pc.binmode ();
	}

      fh->init (handle, GENERIC_READ | GENERIC_WRITE, bin);
      set_std_handle (fd);
      paranoid_printf ("fd %d, handle %p", fd, handle);
    }
}

fhandler_base *
dtable::build_fhandler_from_name (int fd, const char *name, HANDLE handle,
				  path_conv& pc, unsigned opt, suffix_info *si)
{
  pc.check (name, opt | PC_NULLEMPTY | PC_FULL | PC_POSIX, si);
  if (pc.error)
    {
      set_errno (pc.error);
      return NULL;
    }

  if (!pc.exists () && handle)
    pc.fillin (handle);

  fhandler_base *fh = build_fhandler (fd, pc.get_devn (),
				      pc.return_and_clear_normalized_path (),
				      pc, pc.get_unitn ());
  return fh;
}

fhandler_base *
dtable::build_fhandler (int fd, DWORD dev, const char *unix_name,
			const char *win32_name, int unit)
{
  return build_fhandler (fd, dev, cstrdup (unix_name), win32_name, unit);
}

#define cnew(name) new ((void *) ccalloc (HEAP_FHANDLER, 1, sizeof (name))) name
fhandler_base *
dtable::build_fhandler (int fd, DWORD dev, char *unix_name,
			const char *win32_name, int unit)
{
  fhandler_base *fh;

  dev &= FH_DEVMASK;
  switch (dev)
    {
      case FH_TTYM:
	fh = cnew (fhandler_tty_master) (unit);
	break;
      case FH_CONSOLE:
      case FH_CONIN:
      case FH_CONOUT:
	if ((fh = cnew (fhandler_console) ()))
	  inc_console_fds ();
	break;
      case FH_PTYM:
	fh = cnew (fhandler_pty_master) ();
	break;
      case FH_TTYS:
	if (unit < 0)
	  fh = cnew (fhandler_tty_slave) ();
	else
	  fh = cnew (fhandler_tty_slave) (unit);
	break;
      case FH_WINDOWS:
	fh = cnew (fhandler_windows) ();
	break;
      case FH_SERIAL:
	fh = cnew (fhandler_serial) (unit);
	break;
      case FH_PIPE:
      case FH_PIPER:
      case FH_PIPEW:
	fh = cnew (fhandler_pipe) (dev);
	break;
      case FH_SOCKET:
	if ((fh = cnew (fhandler_socket) ()))
	  inc_need_fixup_before ();
	break;
      case FH_DISK:
	fh = cnew (fhandler_disk_file) ();
	break;
      case FH_CYGDRIVE:
	fh = cnew (fhandler_cygdrive) (unit);
	break;
      case FH_FLOPPY:
	fh = cnew (fhandler_dev_floppy) (unit);
	break;
      case FH_TAPE:
	fh = cnew (fhandler_dev_tape) (unit);
	break;
      case FH_NULL:
	fh = cnew (fhandler_dev_null) ();
	break;
      case FH_ZERO:
	fh = cnew (fhandler_dev_zero) ();
	break;
      case FH_RANDOM:
	fh = cnew (fhandler_dev_random) (unit);
	break;
      case FH_MEM:
	fh = cnew (fhandler_dev_mem) (unit);
	break;
      case FH_CLIPBOARD:
	fh = cnew (fhandler_dev_clipboard) ();
	break;
      case FH_OSS_DSP:
	fh = cnew (fhandler_dev_dsp) ();
	break;
      case FH_PROC:
	fh = cnew (fhandler_proc) ();
	break;
      case FH_REGISTRY:
	fh = cnew (fhandler_registry) ();
	break;
      case FH_PROCESS:
	fh = cnew (fhandler_process) ();
	break;
      default:
	system_printf ("internal error -- unknown device - %p", dev);
	fh = NULL;
    }

  if (unix_name)
    {
      char new_win32_name[strlen (unix_name) + 1];
      if (!win32_name)
	{
	  char *p;
	  /* FIXME: ? Should we call win32_device_name here?