/*      $NetBSD: getopt.c,v 1.29 2014/06/05 22:00:22 christos Exp $     */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1987, 1993, 1994
 *      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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "un-namespace.h"

#include "libc_private.h"

int     opterr = 1,             /* if error message should be printed */
        optind = 1,             /* index into parent argv vector */
        optopt,                 /* character checked for validity */
        optreset;               /* reset getopt */
char    *optarg;                /* argument associated with option */

#define BADCH   (int)'?'
#define BADARG  (int)':'
static char EMSG[] = "";
/*
 * getopt --
 *      Parse argc/argv argument vector.
 */
int
getopt(int nargc, char * const nargv[], const char *ostr)
{
        static char *place = EMSG;              /* option letter processing */
        char *oli;                              /* option letter list index */

        if (optreset || *place == 0) {          /* update scanning pointer */
                optreset = 0;
                place = nargv[optind];
                if (optind >= nargc || *place++ != '-') {
                        /* Argument is absent or is not an option */
                        place = EMSG;
                        return (-1);
                }
                optopt = *place++;
                if (optopt == '-' && *place == 0) {
                        /* "--" => end of options */
                        ++optind;
                        place = EMSG;
                        return (-1);
                }
                if (optopt == 0) {
                        /* Solitary '-', treat as a '-' option
                           if the program (eg su) is looking for it. */
                        place = EMSG;
                        if (strchr(ostr, '-') == NULL)
                                return (-1);
                        optopt = '-';
                }
        } else
                optopt = *place++;

        /* See if option letter is one the caller wanted... */
        if (optopt == ':' || (oli = strchr(ostr, optopt)) == NULL) {
                if (*place == 0)
                        ++optind;
                if (opterr && *ostr != ':')
                        (void)fprintf(stderr,
                            "%s: illegal option -- %c\n", _getprogname(),
                            optopt);
                return (BADCH);
        }

        /* Does this option need an argument? */
        if (oli[1] != ':') {
                /* don't need argument */
                optarg = NULL;
                if (*place == 0)
                        ++optind;
        } else {
                /* Option-argument is either the rest of this argument or the
                   entire next argument. */
                if (*place)
                        optarg = place;
                else if (oli[2] == ':')
                        /*
                         * GNU Extension, for optional arguments if the rest of
                         * the argument is empty, we return NULL
                         */
                        optarg = NULL;
                else if (nargc > ++optind)
                        optarg = nargv[optind];
                else {
                        /* option-argument absent */
                        place = EMSG;
                        if (*ostr == ':')
                                return (BADARG);
                        if (opterr)
                                (void)fprintf(stderr,
                                    "%s: option requires an argument -- %c\n",
                                    _getprogname(), optopt);
                        return (BADCH);
                }
                place = EMSG;
                ++optind;
        }
        return (optopt);                        /* return option letter */
}