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/* Copyright (C) 1993, 1996, 1997, 1998 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 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.

   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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, write to the Free

   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA

   02111-1307 USA.  */

#include <errno.h>

#include <string.h>

#include <termios.h>

#include <sys/ioctl.h>

#include <sys/types.h>

/* The difference here is that the termios structure used in the

   kernel is not the same as we use in the libc.  Therefore we must

   translate it here.  */

#include "kernel_termios.h"

/* This is a gross hack around a kernel bug.  If the cfsetispeed functions

   is called with the SPEED argument set to zero this means use the same

   speed as for output.  But we don't have independent input and output

   speeds and therefore cannot record this.

   We use an unused bit in the `c_iflag' field to keep track of this

   use of `cfsetispeed'.  The value here must correspond to the one used

   in `speed.c'.  */

#if !defined _HAVE_C_ISPEED || !defined _HAVE_C_OSPEED

# define IBAUD0 020000000000

#else

/* If we have separate values for input and output speed don't bother

   with this.  Define the value as zero so the compiler sees we don't

   have to do the AND below.  */

# define IBAUD0 0

#endif

/* Set the state of FD to *TERMIOS_P.  */

int tcsetattr (int fd, int optional_actions, const struct termios *termios_p)

{

    struct __kernel_termios k_termios;

    unsigned long int cmd;

    int retval;

    switch (optional_actions)

    {

        case TCSANOW:

            cmd = TCSETS;

            break;

        case TCSADRAIN:

            cmd = TCSETSW;

            break;

        case TCSAFLUSH:

            cmd = TCSETSF;

            break;

        default:

            __set_errno (EINVAL);

            return -1;

    }

    k_termios.c_iflag = termios_p->c_iflag & ~IBAUD0;

    k_termios.c_oflag = termios_p->c_oflag;

    k_termios.c_cflag = termios_p->c_cflag;

    k_termios.c_lflag = termios_p->c_lflag;

    k_termios.c_line = termios_p->c_line;

#ifdef _HAVE_C_ISPEED

    k_termios.c_ispeed = termios_p->c_ispeed;

#endif

#ifdef _HAVE_C_OSPEED

    k_termios.c_ospeed = termios_p->c_ospeed;

#endif

    memcpy (&k_termios.c_cc[0], &termios_p->c_cc[0],

            __KERNEL_NCCS * sizeof (cc_t));

    retval = ioctl (fd, cmd, &k_termios);

    if (retval == 0 && cmd == TCSETS)

    {

        /* The Linux kernel has a bug which silently ignore the invalid

           c_cflag on pty. We have to check it here. */

        int save = errno;

        retval = ioctl (fd, TCGETS, &k_termios);

        if (retval)

        {

            /* We cannot verify if the setting is ok. We don't return

               an error (?). */

            __set_errno (save);

            retval = 0;

        }

        else if ((termios_p->c_cflag & (PARENB | CREAD))

                != (k_termios.c_cflag & (PARENB | CREAD))

                || ((termios_p->c_cflag & CSIZE)

                    && ((termios_p->c_cflag & CSIZE)

                        != (k_termios.c_cflag & CSIZE))))

        {

            /* It looks like the Linux kernel silently changed the

               PARENB/CREAD/CSIZE bits in c_cflag. Report it as an

               error. */

            __set_errno (EINVAL);

            retval = -1;

        }

    }

    return retval;

}