/*      $NetBSD: getopt.c,v 1.2 2024/06/29 07:56:56 rin Exp $   */

/*
* 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 <sys/cdefs.h>
__RCSID("$NetBSD: getopt.c,v 1.2 2024/06/29 07:56:56 rin Exp $");

#if defined(_KERNEL) || defined(_STANDALONE)

#include <lib/libsa/stand.h>
#include <lib/libkern/libkern.h>

#define EPRINTF(fmt, args...)   printf(fmt, ##args)

#else

#include "namespace.h"

#include <assert.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#ifdef __weak_alias
__weak_alias(getopt,_getopt)
#endif

#define EPRINTF(fmt, args...)                                           \
   fprintf(stderr, "%s: " fmt, getprogname(), ##args)

#endif /* !_KERNEL && !_STANDALONE */

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)':'
#define EMSG    ""

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

       _DIAGASSERT(nargv != NULL);
       _DIAGASSERT(ostr != NULL);

       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)EPRINTF("unknown option -- %c\n", 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 = __UNCONST(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)EPRINTF(
                                   "option requires an argument -- %c\n",
                                   optopt);
                       return (BADCH);
               }
               place = EMSG;
               ++optind;
       }
       return (optopt);                        /* return option letter */
}