/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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 "namespace.h"
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/filio.h>
#include <fcntl.h>
#include <dirent.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>
#include <string.h>
#include <paths.h>
#include <errno.h>
#include "reentrant.h"
#include <ssp/ssp.h>
#include "un-namespace.h"

#include "libc_private.h"

static char ttyname_buf[sizeof(_PATH_DEV) + MAXNAMLEN];

static once_t           ttyname_init_once = ONCE_INITIALIZER;
static thread_key_t     ttyname_key;
static int              ttyname_keycreated = 0;

int
__ssp_real(ttyname_r)(int fd, char *buf, size_t len)
{
        size_t used;

        /* Don't write off the end of a zero-length buffer. */
        if (len < 1)
                return (ERANGE);

        *buf = '\0';

        /* Must be a terminal. */
        if (!isatty(fd))
                return (errno);
        /* Must have enough room */
        if (len <= sizeof(_PATH_DEV))
                return (ERANGE);

        strcpy(buf, _PATH_DEV);
        used = strlen(buf);
        if (fdevname_r(fd, buf + used, len - used) == NULL)
                return (errno == EINVAL ? ERANGE : errno);
        return (0);
}

static void
ttyname_keycreate(void)
{
        ttyname_keycreated = (thr_keycreate(&ttyname_key, free) == 0);
}

char *
ttyname(int fd)
{
        char    *buf;

        if (thr_main() != 0)
                buf = ttyname_buf;
        else {
                if (thr_once(&ttyname_init_once, ttyname_keycreate) != 0 ||
                    !ttyname_keycreated)
                        return (NULL);
                if ((buf = thr_getspecific(ttyname_key)) == NULL) {
                        if ((buf = malloc(sizeof ttyname_buf)) == NULL)
                                return (NULL);
                        if (thr_setspecific(ttyname_key, buf) != 0) {
                                free(buf);
                                return (NULL);
                        }
                }
        }

        if (ttyname_r(fd, buf, sizeof ttyname_buf) != 0)
                return (NULL);
        return (buf);
}