/*      $NetBSD: ttyname.c,v 1.26 2012/06/12 18:17:04 joerg Exp $       */

/*
* Copyright (c) 1988, 1993
*      The Regents of the University of California.  All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*/

#include <sys/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)ttyname.c   8.2 (Berkeley) 1/27/94";
#else
__RCSID("$NetBSD: ttyname.c,v 1.26 2012/06/12 18:17:04 joerg Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#include "namespace.h"
#include <sys/ioctl.h>
#include <sys/stat.h>

#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <paths.h>
#include <string.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>

#ifdef __weak_alias
__weak_alias(ttyname,_ttyname)
__weak_alias(ttyname_r,_ttyname_r)
#endif

int
ttyname_r(int fd, char *buf, size_t len)
{
       struct stat sb;
       struct termios ttyb;
       struct ptmget ptm;

       _DIAGASSERT(fd != -1);

       /* If it is a pty, deal with it quickly */
       if (ioctl(fd, TIOCPTSNAME, &ptm) != -1) {
               if (strlcpy(buf, ptm.sn, len) >= len) {
                       return ERANGE;
               }
               return 0;
       }

       /* Must be a terminal. */
       if (tcgetattr(fd, &ttyb) == -1)
               return errno;

       if (fstat(fd, &sb))
               return errno;

       if (strlcpy(buf, _PATH_DEV, len) >= len)
               return ERANGE;
       buf += strlen(_PATH_DEV);
       len -= strlen(_PATH_DEV);
       return devname_r(sb.st_rdev, sb.st_mode & S_IFMT, buf, len);
}

char *
ttyname(int fd)
{
       static char buf[PATH_MAX];
       int rv;

       rv = ttyname_r(fd, buf, sizeof(buf));
       if (rv != 0) {
               errno = rv;
               return NULL;
       }
       return buf;
}