glibc/sysdeps/posix/ttyname_r.c

157 lines
3.7 KiB
C

/* Copyright (C) 1991-2016 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
<http://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>
#ifndef MIN
# define MIN(a, b) ((a) < (b) ? (a) : (b))
#endif
static const char dev[] = "/dev";
static int getttyname_r (int fd, char *buf, size_t buflen,
dev_t mydev, ino_t myino, int save,
int *dostat) __THROW internal_function;
static int
internal_function
getttyname_r (int fd, char *buf, size_t buflen, dev_t mydev, ino_t myino,
int save, int *dostat)
{
struct stat st;
DIR *dirstream;
struct dirent *d;
dirstream = __opendir (dev);
if (dirstream == NULL)
{
*dostat = -1;
return errno;
}
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"))
{
char *cp;
size_t needed = _D_EXACT_NAMLEN (d) + 1;
if (needed > buflen)
{
*dostat = -1;
(void) __closedir (dirstream);
__set_errno (ERANGE);
return ERANGE;
}
cp = __stpncpy (&buf[sizeof (dev)], d->d_name, needed);
cp[0] = '\0';
if (stat (buf, &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);
__set_errno (save);
return 0;
}
}
(void) __closedir (dirstream);
__set_errno (save);
/* It is not clear what to return in this case. `isatty' says FD
refers to a TTY but no entry in /dev has this inode. */
return ENOTTY;
}
/* Store at most BUFLEN character of the pathname of the terminal FD is
open on in BUF. Return 0 on success, otherwise an error number. */
int
__ttyname_r (int fd, char *buf, size_t buflen)
{
struct stat st;
int dostat = 0;
int save = errno;
int ret;
/* Test for the absolute minimal size. This makes life easier inside
the loop. */
if (!buf)
{
__set_errno (EINVAL);
return EINVAL;
}
if (buflen < (int) (sizeof (dev) + 1))
{
__set_errno (ERANGE);
return ERANGE;
}
if (!__isatty (fd))
{
__set_errno (ENOTTY);
return ENOTTY;
}
if (fstat (fd, &st) < 0)
return errno;
/* Prepare the result buffer. */
memcpy (buf, dev, sizeof (dev) - 1);
buf[sizeof (dev) - 1] = '/';
buflen -= sizeof (dev);
#ifdef _STATBUF_ST_RDEV
ret = getttyname_r (fd, buf, buflen, st.st_rdev, st.st_ino, save,
&dostat);
#else
ret = getttyname_r (fd, buf, buflen, st.st_dev, st.st_ino, save,
&dostat);
#endif
if (ret && dostat != -1)
{
dostat = 1;
#ifdef _STATBUF_ST_RDEV
ret = getttyname_r (fd, buf, buflen, st.st_rdev, st.st_ino,
save, &dostat);
#else
ret = getttyname_r (fd, buf, buflen, st.st_dev, st.st_ino,
save, &dostat);
#endif
}
return ret;
}
weak_alias (__ttyname_r, ttyname_r)