amiga-clib2/library/termios_tcflush.c

/*
 * $Id: termios_tcflush.c,v 1.3 2005-07-06 18:48:53 obarthel Exp $
 *
 * :ts=4
 *
 * Portable ISO 'C' (1994) runtime library for the Amiga computer
 * Copyright (c) 2002-2005 by Olaf Barthel <olsen@sourcery.han.de>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Neither the name of Olaf Barthel nor the names of contributors
 *     may be used to endorse or promote products derived from this
 *     software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef	_TERMIOS_HEADERS_H
#include "termios_headers.h"
#endif /* _TERMIOS_HEADERS_H */

/****************************************************************************/

/*
 * This is a bit messy and might possibly be done in a better way, but console
 * termios support is a bit of a hack at best.
 * tcflush() could possibly be implemented with using CMD_CLEAR with the
 * console.device, but this would be just as messy and possibly break
 * even more if e.g. stdin is a pipe.
 */

int
tcflush(int file_descriptor,int queue)
{
	int result = ERROR;
	struct fd *fd;
	char buf[64];
	struct termios *tios;
	BPTR file;

	ENTER();

	SHOWVALUE(file_descriptor);

	if(__check_abort_enabled)
		__check_abort();

	__stdio_lock();

	fd = __get_file_descriptor(file_descriptor);
	if(fd == NULL || FLAG_IS_CLEAR(fd->fd_Flags,FDF_TERMIOS))
	{
		__set_errno(EBADF);
		goto out;
	}

	__fd_lock(fd);

	if(queue < TCIFLUSH || queue > TCIOFLUSH)
	{
		SHOWMSG("Invalid queue specified to tcflush().");

		__set_errno(EINVAL);
		goto out;
	}

	file = fd->fd_DefaultFile;

	#if defined(__THREAD_SAFE)
	{
		if(FLAG_IS_SET(fd->fd_Flags,FDF_STDIO))
		{
			switch(fd->fd_DefaultFile)
			{
				case STDIN_FILENO:

					file = Input();
					break;

				case STDOUT_FILENO:

					file = Output();
					break;

				case STDERR_FILENO:

					#if defined(__amigaos4__)
					{
						file = ErrorOutput();
					}
					#else
					{
						struct Process * this_process = (struct Process *)FindTask(NULL);

						file = this_process->pr_CES;
					}
					#endif /* __amigaos4__ */

					/* The following is rather controversial; if the standard error stream
					   is unavailable, we default to reuse the standard output stream. This
					   is problematic if the standard output stream was redirected and should
					   not be the same as the standard error output stream. */
					if(file == ZERO)
						file = Output();

					break;

				default:

					file = ZERO;
					break;
			}
		}
	}
	#endif /* __THREAD_SAFE */

	tios = fd->fd_Aux;

	if(queue == TCIFLUSH || queue == TCIOFLUSH)
	{
		LONG num_bytes_read;

		if(file == ZERO)
		{
			__set_errno(EBADF);
			goto out;
		}

		/* Set raw mode so we can read without blocking. */
		if(FLAG_IS_SET(tios->c_lflag,ICANON))
		{
			SetMode(file,DOSTRUE);

			SET_FLAG(fd->fd_Flags,FDF_NON_BLOCKING);
		}

		while(WaitForChar(file,1) != DOSFALSE)
		{
			if(__check_abort_enabled)
				__check_abort();

			/* Read away available data. (upto 8k) */
			num_bytes_read = Read(file,buf,64);
			if(num_bytes_read == ERROR || num_bytes_read == 0)
				break;
		}

		/* Restore the Raw/Cooked mode. */
		if(FLAG_IS_SET(tios->c_lflag,ICANON))
		{
			SetMode(file,DOSFALSE); /* Set Cooked = Canonical mode. */

			CLEAR_FLAG(fd->fd_Flags,FDF_NON_BLOCKING);
		}

		result = OK;
	}
	else if (queue == TCOFLUSH || queue == TCIOFLUSH)
	{
		/* TODO: Can we actually discard data buffered on the file?
		 * For now we do the same as tcdrain().
		 */
		result = tcdrain(file_descriptor);
	}

 out:

	__fd_unlock(fd);

	__stdio_unlock();

	RETURN(result);
	return(result);
}