glibc/mach/devstream.c

/* stdio on a Mach device port.
   Translates \n to \r\n on output, echos and translates \r to \n on input.

Copyright (C) 1992, 1993, 1994, 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.

The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.

The GNU C Library 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
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB.  If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA.  */

#include <stdio.h>
#include <mach.h>
#include <device/device.h>
#include <errno.h>
#include <string.h>

static int
input (FILE *f)
{
  kern_return_t err;
  char *buffer;
  size_t to_read;
  mach_msg_type_number_t nread;
  char c;

  if (f->__buffer == NULL)
    {
      buffer = &c;
      to_read = 1;
    }
  else
    {
      buffer = f->__buffer;
      to_read = f->__bufsize;
    }

  f->__eof = 0;

  nread = to_read;
  err = device_read_inband ((device_t) f->__cookie, 0, f->__target,
			    to_read, buffer, &nread);

  if (err)
    {
      f->__error = 1;
      f->__bufp = f->__get_limit = f->__put_limit = f->__buffer;
      errno = err;
      return EOF;
    }

  /* Echo it back.  */
  err = device_write_inband ((device_t) f->__cookie, 0, f->__target,
			     buffer, nread, (int *) &to_read);

  /* Translate LF to CR.  */
  {
    char *p;
    for (p = memchr (buffer, '\r', nread); p;
	 p = memchr (p + 1, '\r', (buffer + nread) - (p + 1)))
      *p = '\n';
  }

  if (f->__buffer == NULL)
    return (unsigned char) c;

  f->__get_limit = f->__buffer + nread;
  f->__bufp = f->__buffer;
  f->__put_limit = f->__buffer + (f->__mode.__write ? f->__bufsize : 0);
  return (unsigned char) *f->__bufp++;
}


#if 0
static void
output (FILE *f, int c)
{
  inline void write_some (const char *p, size_t to_write)
    {
      kern_return_t err;
      int wrote;
      while (to_write > 0)
	{
	  if (err = device_write ((device_t) f->__cookie, 0,
				  f->__target, (char *)p,
				  to_write, &wrote))
	    {
	      errno = err;
	      f->__error = 1;
	      break;
	    }
	  p += wrote;
	  to_write -= wrote;
	  f->__target += wrote;
	}
    }

  if (f->__buffer != NULL)
    {
      if (f->__put_limit == f->__buffer)
	{
	  /* Prime the stream for writing.  */
	  f->__put_limit = f->__buffer + f->__bufsize;
	  f->__bufp = f->__buffer;
	  if (c != EOF)
	    {
	      *f->__bufp++ = (unsigned char) c;
	      c = EOF;
	    }
	}


      /* Write out the buffer.  */

      write_some (f->__buffer, f->__bufp - f->__buffer);

      f->__bufp = f->__buffer;
    }

  if (c != EOF && !ferror (f))
    {
      if (f->__linebuf && (unsigned char) c == '\n')
	{
	  static const char nl = '\n';
	  write_some (&nl, 1);
	}
      else
	*f->__bufp++ = (unsigned char) c;
    }
}
#endif


static void
output (FILE *f, int c)
{
  void write_some (const char *p, size_t to_write)
    {
      kern_return_t err;
      int wrote;
      while (to_write > 0)
	{
	  if (err = device_write_inband ((device_t) f->__cookie, 0,
					 f->__target, p, to_write, &wrote))
	    {
	      errno = err;
	      f->__error = 1;
	      break;
	    }
	  p += wrote;
	  to_write -= wrote;
	  f->__target += wrote;
	}
    }
  void write_crlf (void)
    {
      static const char crlf[] = "\r\n";
      write_some (crlf, 2);
    }

  if (f->__buffer == NULL)
    {
      /* The stream is unbuffered.  */

      if (c == '\n')
	write_crlf ();
      else if (c != EOF)
	{
	  char cc = (unsigned char) c;
	  write_some (&cc, 1);
	}

      return;
    }

  if (f->__put_limit == f->__buffer)
    {
      /* Prime the stream for writing.  */
      f->__put_limit = f->__buffer + f->__bufsize;
      f->__bufp = f->__buffer;
      if (c != EOF)
	{
	  *f->__bufp++ = (unsigned char) c;
	  c = EOF;
	}
    }

  {
    /* Search for newlines (LFs) in the buffer.  */

    char *start = f->__buffer, *p = start;

    while (!ferror (f) && (p = memchr (p, '\n', f->__bufp - start)))
      {
	/* Found one.  Replace it with a CR and write out through that CR.  */

	*p = '\r';
	write_some (start, p + 1 - start);

	/* Change it back to an LF; the next iteration will write it out
	   first thing.  Start the next searching iteration one char later.  */

	start = p;
	*p++ = '\n';
      }

    /* Write the remainder of the buffer.  */

    if (!ferror (f))
      write_some (start, f->__bufp - start);
  }

  f->__bufp = f->__buffer;

  if (c != EOF && !ferror (f))
    {
      if (f->__linebuf && (unsigned char) c == '\n')
	write_crlf ();
      else
	*f->__bufp++ = (unsigned char) c;
    }
}

static int
dealloc_ref (void *cookie)
{
  if (mach_port_deallocate (mach_task_self (), (mach_port_t) cookie))
    {
      errno = EINVAL;
      return -1;
    }
  return 0;
}


FILE *
mach_open_devstream (mach_port_t dev, const char *mode)
{
  FILE *stream;

  if (mach_port_mod_refs (mach_task_self (), dev, MACH_PORT_RIGHT_SEND, 1))
    {
      errno = EINVAL;
      return NULL;
    }

  stream = fopencookie ((void *) dev, mode, __default_io_functions);
  if (stream == NULL)
    {
      mach_port_deallocate (mach_task_self (), dev);
      return NULL;
    }

  stream->__room_funcs.__input = input;
  stream->__room_funcs.__output = output;
  stream->__io_funcs.__close = dealloc_ref;
  stream->__io_funcs.__seek = NULL; /* Cannot seek.  */
  stream->__io_funcs.__fileno = NULL; /* No corresponding POSIX.1 fd.  */
  stream->__seen = 1;

  return stream;
}