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/* Copyright (C) 1991, 92, 93, 95, 96 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 <errno.h>
#include <limits.h>
#include <stddef.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#ifndef MIN
# define MIN(a, b) ((a) < (b) ? (a) : (b))
#endif
/* Store at most BUFLEN character of the pathname of the terminal FD is
open on in BUF. Return 0 on success, -1 otherwise. */
int
ttyname_r (fd, buf, buflen)
int fd;
char *buf;
int buflen;
{
static const char dev[] = "/dev";
struct stat st;
dev_t mydev;
ino_t myino;
DIR *dirstream;
struct dirent *d;
int save = errno;
/* Test for the absolute minimal size. This makes life easier inside
the loop. */
if (buflen < (int) (sizeof (dev) + 2))
{
errno = EINVAL;
return -1;
}
if (fstat (fd, &st) < 0)
return -1;
mydev = st.st_dev;
myino = st.st_ino;
dirstream = opendir (dev);
if (dirstream == NULL)
return -1;
/* Prepare the result buffer. */
memcpy (buf, dev, sizeof (dev));
buf[sizeof (dev)] = '/';
buflen -= sizeof (dev) + 1;
while ((d = readdir (dirstream)) != NULL)
if (d->d_fileno == myino)
{
char *cp;
cp = __stpncpy (&buf[sizeof (dev) + 1], d->d_name,
MIN ((int) (_D_EXACT_NAMLEN (d) + 1), buflen));
cp[0] = '\0';
if (stat (buf, &st) == 0 && st.st_dev == mydev)
{
(void) closedir (dirstream);
errno = save;
return 0;
}
}
(void) closedir (dirstream);
errno = save;
return -1;
}
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