fhandler_tty.cc

cygwin, 著名的在win32下模拟unix操作系统的东东

/* fhandler_tty.cc

   Copyright 1997, 1998, 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. */

#include "winsup.h"
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <ctype.h>
#include <limits.h>
#include "cygerrno.h"
#include "security.h"
#include "fhandler.h"
#include "path.h"
#include "dtable.h"
#include "sigproc.h"
#include "pinfo.h"
#include "cygheap.h"
#include "shared_info.h"
#include "cygwin/cygserver.h"
#include "cygthread.h"

/* Tty master stuff */

fhandler_tty_master NO_COPY *tty_master;

static DWORD WINAPI process_input (void *);		// Input queue thread
static DWORD WINAPI process_output (void *);		// Output queue thread
static DWORD WINAPI process_ioctl (void *);		// Ioctl requests thread

fhandler_tty_master::fhandler_tty_master (int unit)
  : fhandler_pty_master (FH_TTYM, unit), console (NULL)
{
}

int
fhandler_tty_master::init (int ntty)
{
  termios_printf ("Creating master for tty%d", ntty);

  if (init_console ())
    {
      termios_printf ("can't create fhandler");
      return -1;
    }

  termios ti;
  memset (&ti, 0, sizeof (ti));
  console->tcsetattr (0, &ti);

  ttynum = ntty;

  cygwin_shared->tty[ttynum]->common_init (this);

  inuse = get_ttyp ()->create_inuse (TTY_MASTER_ALIVE);

  cygthread *h;
  h = new cygthread (process_input, cygself, "ttyin");
  h->SetThreadPriority (THREAD_PRIORITY_HIGHEST);
  h->zap_h ();

  h = new cygthread (process_ioctl, cygself, "ttyioctl");
  h->SetThreadPriority (THREAD_PRIORITY_HIGHEST);
  h->zap_h ();

  h = new cygthread (process_output, cygself, "ttyout");
  h->SetThreadPriority (THREAD_PRIORITY_HIGHEST);
  h->zap_h ();

  return 0;
}

#ifdef DEBUGGING
static class mutex_stack
{
public:
  const char *fn;
  int ln;
  const char *tname;
} ostack[100];

static int osi;
#endif /*DEBUGGING*/

DWORD
fhandler_tty_common::__acquire_output_mutex (const char *fn, int ln,
					   DWORD ms)
{
  if (strace.active)
    strace.prntf (_STRACE_TERMIOS, fn, "(%d): tty output_mutex: waiting %d ms", ln, ms);
  DWORD res = WaitForSingleObject (output_mutex, ms);
  if (res == WAIT_OBJECT_0)
    {
#ifndef DEBUGGING
      if (strace.active)
	strace.prntf (_STRACE_TERMIOS, fn, "(%d): tty output_mutex: acquired", ln, res);
#else
      ostack[osi].fn = fn;
      ostack[osi].ln = ln;
      ostack[osi].tname = cygthread::name ();
      termios_printf ("acquired for %s:%d, osi %d", fn, ln, osi);
      osi++;
#endif
    }
  return res;
}

void
fhandler_tty_common::__release_output_mutex (const char *fn, int ln)
{
  if (ReleaseMutex (output_mutex))
    {
#ifndef DEBUGGING
      if (strace.active)
	strace.prntf (_STRACE_TERMIOS, fn, "(%d): tty output_mutex released", ln);
#else
      if (osi > 0)
	osi--;
      termios_printf ("released at %s:%d, osi %d", fn, ln, osi);
      termios_printf ("  for %s:%d (%s)", ostack[osi].fn, ostack[osi].ln, ostack[osi].tname);
      ostack[osi].ln = -ln;
#endif
    }
}

/* Process tty input. */

void
fhandler_pty_master::doecho (const void *str, DWORD len)
{
  acquire_output_mutex (INFINITE);
  if (!WriteFile (get_ttyp ()->to_master, str, len, &len, NULL))
    termios_printf ("Write to %p failed, %E", get_ttyp ()->to_master);
//  WaitForSingleObject (output_done_event, INFINITE);
  release_output_mutex ();
}

int
fhandler_pty_master::accept_input ()
{
  DWORD bytes_left, written;
  DWORD n;
  DWORD rc;
  char* p;

  rc = WaitForSingleObject (input_mutex, INFINITE);

  bytes_left = n = eat_readahead (-1);
  get_ttyp ()->read_retval = 0;
  p = rabuf;

  if (n != 0)
    {
      while (bytes_left > 0)
	{
	  termios_printf ("about to write %d chars to slave", bytes_left);
	  rc = WriteFile (get_output_handle (), p, bytes_left, &written, NULL);
	  if (!rc)
	    {
	      debug_printf ("error writing to pipe %E");
	      break;
	    }
	  get_ttyp ()->read_retval += written;
	  p += written;
	  bytes_left -= written;
	  if (bytes_left > 0)
	    {
	      debug_printf ("to_slave pipe is full");
	      SetEvent (input_available_event);
	      ReleaseMutex (input_mutex);
	      Sleep (10);
	      rc = WaitForSingleObject (input_mutex, INFINITE);
	    }
	}
    }
  else
    termios_printf ("sending EOF to slave");
  SetEvent (input_available_event);
  ReleaseMutex (input_mutex);
  return get_ttyp ()->read_retval;
}

static DWORD WINAPI
process_input (void *)
{
  char rawbuf[INP_BUFFER_SIZE];

  while (1)
    {
      int nraw = tty_master->console->read ((void *) rawbuf,
				      (size_t) INP_BUFFER_SIZE);
      (void) tty_master->line_edit (rawbuf, nraw);
    }
}

bool
fhandler_pty_master::hit_eof ()
{
  if (get_ttyp ()->was_opened && !get_ttyp ()->slave_alive ())
    {
      /* We have the only remaining open handle to this pty, and
	 the slave pty has been opened at least once.  We treat
	 this as EOF.  */
      termios_printf ("all other handles closed");
      return 1;
    }
  return 0;
}

/* Process tty output requests */

int
fhandler_pty_master::process_slave_output (char *buf, size_t len, int pktmode_on)
{
  size_t rlen;
  char outbuf[OUT_BUFFER_SIZE + 1];
  DWORD n;
  int column = 0;
  int rc = 0;

  if (len == 0)
    goto out;

  if (need_nl)
    {
      /* We need to return a left over \n character, resulting from
	 \r\n conversion.  Note that we already checked for FLUSHO and
	 output_stopped at the time that we read the character, so we
	 don't check again here.  */
      buf[0] = '\n';
      need_nl = 0;
      rc = 1;
      goto out;
    }


  for (;;)
    {
      /* Set RLEN to the number of bytes to read from the pipe.  */
      rlen = len;
      if (get_ttyp ()->ti.c_oflag & OPOST && get_ttyp ()->ti.c_oflag & ONLCR)
	{
	  /* We are going to expand \n to \r\n, so don't read more than
	     half of the number of bytes requested.  */
	  rlen /= 2;
	  if (rlen == 0)
	    rlen = 1;
	}
      if (rlen > sizeof outbuf)
	rlen = sizeof outbuf;

      HANDLE handle = get_io_handle ();

      n = 0; // get_readahead_into_buffer (outbuf, len);
      if (!n)
	{
	  /* Doing a busy wait like this is quite inefficient, but nothing
	     else seems to work completely.  Windows should provide some sort
	     of overlapped I/O for pipes, or something, but it doesn't.  */
	  while (1)
	    {
	      if (!PeekNamedPipe (handle, NULL, 0, NULL, &n, NULL))
		goto err;
	      if (n > 0)
		break;
	      if (hit_eof ())
		goto out;
	      if (n == 0 && is_nonblocking ())
		{
		  set_errno (EAGAIN);
		  rc = -1;
		  break;
		}

	      Sleep (10);
	    }

	  if (ReadFile (handle, outbuf, rlen, &n, NULL) == FALSE)
	    goto err;
	}

      termios_printf ("bytes read %u", n);
      get_ttyp ()->write_error = 0;
      if (output_done_event != NULL)
	SetEvent (output_done_event);

      if (get_ttyp ()->ti.c_lflag & FLUSHO)
	continue;

      char *optr;
      optr = buf;
      if (pktmode_on)
	*optr++ = TIOCPKT_DATA;

      if (!(get_ttyp ()->ti.c_oflag & OPOST))	// post-process output
	{
	  memcpy (optr, outbuf, n);
	  optr += n;
	}
      else					// raw output mode
	{
	  char *iptr = outbuf;

	  while (n--)
	    {
	      switch (*iptr)
		{
		case '\r':
		  if ((get_ttyp ()->ti.c_oflag & ONOCR) && column == 0)
		    {
		      iptr++;
		      continue;
		    }
		  if (get_ttyp ()->ti.c_oflag & OCRNL)
		    *iptr = '\n';
		  else
		    column = 0;
		  break;
		case '\n':
		  if (get_ttyp ()->ti.c_oflag & ONLCR)
		    {
		      *optr++ = '\r';
		      column = 0;
		    }
		  if (get_ttyp ()->ti.c_oflag & ONLRET)
		    column = 0;
		  break;
		default:
		  column++;
		  break;
		}

	      /* Don't store data past the end of the user's buffer.  This
		 can happen if the user requests a read of 1 byte when
		 doing \r\n expansion.  */
	      if (optr - buf >= (int) len)
		{
		  if (*iptr != '\n' || n != 0)
		    system_printf ("internal error: %d unexpected characters", n);
		  need_nl = 1;
		  break;
		}

	      *optr++ = *iptr++;
	    }
	}
      rc = optr - buf;
      break;

    err:
      if (GetLastError () == ERROR_BROKEN_PIPE)
	rc = 0;
      else
	{
	  __seterrno ();
	  rc = -1;
	}
      break;
    }

out:
  termios_printf ("returning %d", rc);
  return rc;
}

static DWORD WINAPI
process_output (void *)
{
  char buf[OUT_BUFFER_SIZE * 2];

  for (;;)
    {
      int n = tty_master->process_slave_output (buf, OUT_BUFFER_SIZE, 0);
      if (n <= 0)
	{
	  if (n < 0)
	    termios_printf ("ReadFile %E");
	  ExitThread (0);
	}
      n = tty_master->console->write ((void *) buf, (size_t) n);
      tty_master->get_ttyp ()->write_error = n == -1 ? get_errno () : 0;
    }
}


/* Process tty ioctl requests */

static DWORD WINAPI
process_ioctl (void *)
{
  while (1)
    {
      WaitForSingleObject (tty_master->ioctl_request_event, INFINITE);
      termios_printf ("ioctl() request");
      tty_master->get_ttyp ()->ioctl_retval =
      tty_master->console->ioctl (tty_master->get_ttyp ()->cmd,
			     (void *) &tty_master->get_ttyp ()->arg);
      SetEvent (tty_master->ioctl_done_event);
    }
}

/**********************************************************************/
/* Tty slave stuff */

fhandler_tty_slave::fhandler_tty_slave (int num)
  : fhandler_tty_common (FH_TTYS, num)
{
  set_r_no_interrupt (1);
}

fhandler_tty_slave::fhandler_tty_slave ()
  : fhandler_tty_common (FH_TTYS, 0)
{
  set_r_no_interrupt (1);
}

/* FIXME: This function needs to close handles when it has
   a failing condition. */
int
fhandler_tty_slave::open (path_conv *, int flags, mode_t)
{
  tcinit (cygwin_shared->tty[ttynum]);

  attach_tty (ttynum);
  tc->set_ctty (ttynum, flags);

  set_flags ((flags & ~O_TEXT) | O_BINARY);
  /* Create synchronisation events */
  char buf[40];

  /* output_done_event may or may not exist.  It will exist if the tty
     was opened by fhandler_tty_master::init, normally called at
     startup if use_tty is non-zero.  It will not exist if this is a
     pty opened by fhandler_pty_master::open.  In the former case, tty
     output is handled by a separate thread which controls output.  */
  __small_sprintf (buf, OUTPUT_DONE_EVENT, ttynum);
  output_done_event = OpenEvent (EVENT_ALL_ACCESS, TRUE, buf);

  if (!(output_mutex = get_ttyp ()->open_output_mutex ()))
    {
      termios_printf ("open output mutex failed, %E");
      __seterrno ();
      return 0;
    }
  if (!(input_mutex = get_ttyp ()->open_input_mutex ()))
    {
      termios_printf ("open input mutex failed, %E");
      __seterrno ();
      return 0;
    }
  __small_sprintf (buf, INPUT_AVAILABLE_EVENT, ttynum);
  if (!(input_available_event = OpenEvent (EVENT_ALL_ACCESS, TRUE, buf)))
    {
      termios_printf ("open input event failed, %E");
      __seterrno ();
      return 0;
    }

  /* The ioctl events may or may not exist.  See output_done_event,
     above.  */
  __small_sprintf (buf, IOCTL_REQUEST_EVENT, ttynum);
  ioctl_request_event = OpenEvent (EVENT_ALL_ACCESS, TRUE, buf);
  __small_sprintf (buf, IOCTL_DONE_EVENT, ttynum);
  ioctl_done_event = OpenEvent (EVENT_ALL_ACCESS, TRUE, buf);

  /* FIXME: Needs a method to eliminate tty races */
  {
    acquire_output_mutex (500);
    inuse = get_ttyp ()->create_inuse (TTY_SLAVE_ALIVE);
    get_ttyp ()->was_opened = TRUE;
    release_output_mutex ();
  }

  /* Duplicate tty handles.  */

  if (!get_ttyp ()->from_slave || !get_ttyp ()->to_slave)
    {
      termios_printf ("tty handles have been closed");
      set_errno (EACCES);
      return 0;
    }

  HANDLE from_master_local, to_master_local;

  if (!wincap.has_security () ||
      cygserver_running == CYGSERVER_UNAVAIL ||
      !cygserver_attach_tty (&from_master_local, &to_master_local))
    {
      termios_printf ("cannot dup handles via server. using old method.");

      HANDLE tty_owner = OpenProcess (PROCESS_DUP_HANDLE, FALSE,
				      get_ttyp ()->master_pid);
      termios_printf ("tty own handle %p",tty_owner);
      if (tty_owner == NULL)
	{
	  termios_printf ("can't open tty (%d) handle process %d",
			  ttynum, get_ttyp ()->master_pid);
	  __seterrno ();
	  return 0;
	}

      if (!DuplicateHandle (tty_owner, get_ttyp ()->from_master,
			    hMainProc, &from_master_local, 0, TRUE,
			    DUPLICATE_SAME_ACCESS))
	{
	  termios_printf ("can't duplicate input, %E");
	  __seterrno ();
	  return 0;
	}

      if (!DuplicateHandle (tty_owner, get_ttyp ()->to_master,
			  hMainProc, &to_master_local, 0, TRUE,
			  DUPLICATE_SAME_ACCESS))
	{
	  termios_printf ("can't duplicate output, %E");
	  __seterrno ();
	  return 0;
	}
      CloseHandle (tty_owner);
    }

  termios_printf ("duplicated from_master %p->%p from tty_owner",
      get_ttyp ()->from_master, from_master_local);
  termios_printf ("duplicated to_master %p->%p from tty_owner",
      get_ttyp ()->to_master, to_master_local);

  set_io_handle (from_master_local);
  set_output_handle (to_master_local);

  set_open_status ();
  termios_printf ("tty%d opened", ttynum);

  return 1;
}

int
fhandler_tty_slave::cygserver_attach_tty (LPHANDLE from_master_ptr,
					  LPHANDLE to_master_ptr)
{
  if (!from_master_ptr || !to_master_ptr)
    return 0;

  client_request_attach_tty req ((DWORD) get_ttyp ()->master_pid,
				 (HANDLE) get_ttyp ()->from_master,
				 (HANDLE) get_ttyp ()->to_master);

  if (req.make_request () == -1 || req.error_code ())
    return 0;

  *from_master_ptr = req.from_master ();
  *to_master_ptr = req.to_master ();
  return 1;
}

void
fhandler_tty_slave::init (HANDLE, DWORD a, mode_t)
{
  int mode = 0;

  a &= GENERIC_READ | GENERIC_WRITE;
  if (a == GENERIC_READ)
    mode = O_RDONLY;
  if (a == GENERIC_WRITE)
    mode = O_WRONLY;
  if (a == (GENERIC_READ | GENERIC_WRITE))
    mode = O_RDWR;

  open (0, mode);
}

int
fhandler_tty_slave::write (const void *ptr, size_t len)
{
  DWORD n, towrite = len;

  termios_printf ("tty%d, write(%x, %d)", ttynum, ptr, len);

  acquire_output_mutex (INFINITE);

  while (len)
    {
      n = min (OUT_BUFFER_SIZE, len);
      char *buf = (char *)ptr;
      ptr = (char *) ptr + n;
      len -= n;

      /* Previous write may have set write_error to != 0.  Check it here.
	 This is less than optimal, but the alternative slows down tty
	 writes enormously. */
      if (get_ttyp ()->write_error)
	{
	  set_errno (get_ttyp ()->write_error);
	  towrite = (DWORD) -1;
	  break;
	}

      if (WriteFile (get_output_handle (), buf, n, &n, NULL) == FALSE)
	{
	  DWORD err = GetLastError ();
	  termios_printf ("WriteFile failed, %E");
	  switch (err)
	    {
	    case ERROR_NO_DATA:
	      err = ERROR_IO_DEVICE;
	    default:
	      __seterrno_from_win_error (err);
	    }