/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1990, 1993
 *      The Regents of the University of California.  All rights reserved.
 * Copyright (c) 2017, 2018
 *      Cyril S. E. Schubert
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * 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 <errno.h>
#include <unistd.h>
#include <stdint.h>
#include <stdio.h>
#include <ssp/ssp.h>
#include "un-namespace.h"
#include "libc_private.h"
#include "local.h"

static inline char *
_gets_s(char *buf, rsize_t n)
{
        int c;
        char *s;

        ORIENT(stdin, -1);
        for (s = buf, n--; (c = __sgetc(stdin)) != '\n' && n > 0 ; n--) {
                if (c == EOF) {
                        if (s == buf) {
                                return (NULL);
                        } else
                                break;
                } else
                        *s++ = c;
        }

        /*
         * If end of buffer reached, discard until \n or eof.
         * Then throw an error.
         */
        if (n == 0) {
                /* discard */
                while ((c = __sgetc(stdin)) != '\n' && c != EOF);
                /* throw the error after lock released prior to exit */
                __throw_constraint_handler_s("gets_s : end of buffer", E2BIG);
                return (NULL);
        }
        *s = 0;
        return (buf);
}

/* ISO/IEC 9899:2011 K.3.7.4.1 */
char *
__ssp_real(gets_s)(char *buf, rsize_t n)
{
        char *ret;
        if (buf == NULL) {
                __throw_constraint_handler_s("gets_s : str is NULL", EINVAL);
                return(NULL);
        } else if (n > RSIZE_MAX) {
                __throw_constraint_handler_s("gets_s : n > RSIZE_MAX",
                        EINVAL);
                return(NULL);
        } else if (n == 0) {
                __throw_constraint_handler_s("gets_s : n == 0", EINVAL);
                return(NULL);
        }

        FLOCKFILE_CANCELSAFE(stdin);
        ret = _gets_s(buf, n);
        FUNLOCKFILE_CANCELSAFE();
        return (ret);
}