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/* Copyright (C) 1991-2021 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, see
<https://www.gnu.org/licenses/>. */
#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>
char *__ttyname;
static char *getttyname (int fd, dev_t mydev, ino_t myino,
int save, int *dostat);
libc_freeres_ptr (static char *getttyname_name);
static char *
getttyname (int fd, dev_t mydev, ino_t myino, int save, int *dostat)
{
static const char dev[] = "/dev";
static size_t namelen;
struct stat st;
DIR *dirstream;
struct dirent *d;
dirstream = __opendir (dev);
if (dirstream == NULL)
{
*dostat = -1;
return NULL;
}
while ((d = __readdir (dirstream)) != NULL)
if (((ino_t) d->d_fileno == myino || *dostat)
&& strcmp (d->d_name, "stdin")
&& strcmp (d->d_name, "stdout")
&& strcmp (d->d_name, "stderr"))
{
size_t dlen = _D_ALLOC_NAMLEN (d);
if (sizeof (dev) + dlen > namelen)
{
free (getttyname_name);
namelen = 2 * (sizeof (dev) + dlen); /* Big enough. */
getttyname_name = malloc (namelen);
if (! getttyname_name)
{
*dostat = -1;
/* Perhaps it helps to free the directory stream buffer. */
(void) __closedir (dirstream);
return NULL;
}
*((char *) __mempcpy (getttyname_name, dev, sizeof (dev) - 1))
= '/';
}
(void) __mempcpy (&getttyname_name[sizeof (dev)], d->d_name, dlen);
if (stat (getttyname_name, &st) == 0
#ifdef _STATBUF_ST_RDEV
&& S_ISCHR (st.st_mode) && st.st_rdev == mydev
#else
&& (ino_t) d->d_fileno == myino && st.st_dev == mydev
#endif
)
{
(void) __closedir (dirstream);
__ttyname = getttyname_name;
__set_errno (save);
return getttyname_name;
}
}
(void) __closedir (dirstream);
__set_errno (save);
return NULL;
}
/* Return the pathname of the terminal FD is open on, or NULL on errors.
The returned storage is good only until the next call to this function. */
char *
ttyname (int fd)
{
struct stat st;
int dostat = 0;
char *name;
int save = errno;
if (!__isatty (fd))
return NULL;
if (fstat (fd, &st) < 0)
return NULL;
#ifdef _STATBUF_ST_RDEV
name = getttyname (fd, st.st_rdev, st.st_ino, save, &dostat);
#else
name = getttyname (fd, st.st_dev, st.st_ino, save, &dostat);
#endif
if (!name && dostat != -1)
{
dostat = 1;
#ifdef _STATBUF_ST_RDEV
name = getttyname (fd, st.st_rdev, st.st_ino, save, &dostat);
#else
name = getttyname (fd, st.st_dev, st.st_ino, save, &dostat);
#endif
}
return name;
}
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