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      1 /*	$NetBSD: getopt.c,v 1.2 2024/06/29 07:56:56 rin Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1987, 1993, 1994
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __RCSID("$NetBSD: getopt.c,v 1.2 2024/06/29 07:56:56 rin Exp $");
     34 
     35 #if defined(_KERNEL) || defined(_STANDALONE)
     36 
     37 #include <lib/libsa/stand.h>
     38 #include <lib/libkern/libkern.h>
     39 
     40 #define	EPRINTF(fmt, args...)	printf(fmt, ##args)
     41 
     42 #else
     43 
     44 #include "namespace.h"
     45 
     46 #include <assert.h>
     47 #include <errno.h>
     48 #include <stdio.h>
     49 #include <stdlib.h>
     50 #include <string.h>
     51 #include <unistd.h>
     52 
     53 #ifdef __weak_alias
     54 __weak_alias(getopt,_getopt)
     55 #endif
     56 
     57 #define	EPRINTF(fmt, args...)						\
     58     fprintf(stderr, "%s: " fmt, getprogname(), ##args)
     59 
     60 #endif /* !_KERNEL && !_STANDALONE */
     61 
     62 int	opterr = 1,		/* if error message should be printed */
     63 	optind = 1,		/* index into parent argv vector */
     64 	optopt,			/* character checked for validity */
     65 	optreset;		/* reset getopt */
     66 char	*optarg;		/* argument associated with option */
     67 
     68 #define	BADCH	(int)'?'
     69 #define	BADARG	(int)':'
     70 #define	EMSG	""
     71 
     72 /*
     73  * getopt --
     74  *	Parse argc/argv argument vector.
     75  */
     76 int
     77 getopt(int nargc, char * const nargv[], const char *ostr)
     78 {
     79 	static const char *place = EMSG;	/* option letter processing */
     80 	const char *oli;			/* option letter list index */
     81 
     82 	_DIAGASSERT(nargv != NULL);
     83 	_DIAGASSERT(ostr != NULL);
     84 
     85 	if (optreset || *place == 0) {		/* update scanning pointer */
     86 		optreset = 0;
     87 		place = nargv[optind];
     88 		if (optind >= nargc || *place++ != '-') {
     89 			/* Argument is absent or is not an option */
     90 			place = EMSG;
     91 			return (-1);
     92 		}
     93 		optopt = *place++;
     94 		if (optopt == '-' && *place == 0) {
     95 			/* "--" => end of options */
     96 			++optind;
     97 			place = EMSG;
     98 			return (-1);
     99 		}
    100 		if (optopt == 0) {
    101 			/* Solitary '-', treat as a '-' option
    102 			   if the program (eg su) is looking for it. */
    103 			place = EMSG;
    104 			if (strchr(ostr, '-') == NULL)
    105 				return -1;
    106 			optopt = '-';
    107 		}
    108 	} else
    109 		optopt = *place++;
    110 
    111 	/* See if option letter is one the caller wanted... */
    112 	if (optopt == ':' || (oli = strchr(ostr, optopt)) == NULL) {
    113 		if (*place == 0)
    114 			++optind;
    115 		if (opterr && *ostr != ':')
    116 			(void)EPRINTF("unknown option -- %c\n", optopt);
    117 		return (BADCH);
    118 	}
    119 
    120 	/* Does this option need an argument? */
    121 	if (oli[1] != ':') {
    122 		/* don't need argument */
    123 		optarg = NULL;
    124 		if (*place == 0)
    125 			++optind;
    126 	} else {
    127 		/* Option-argument is either the rest of this argument or the
    128 		   entire next argument. */
    129 		if (*place)
    130 			optarg = __UNCONST(place);
    131 		else if (oli[2] == ':')
    132 			/*
    133 			 * GNU Extension, for optional arguments if the rest of
    134 			 * the argument is empty, we return NULL
    135 			 */
    136 			optarg = NULL;
    137 		else if (nargc > ++optind)
    138 			optarg = nargv[optind];
    139 		else {
    140 			/* option-argument absent */
    141 			place = EMSG;
    142 			if (*ostr == ':')
    143 				return (BADARG);
    144 			if (opterr)
    145 				(void)EPRINTF(
    146 				    "option requires an argument -- %c\n",
    147 				    optopt);
    148 			return (BADCH);
    149 		}
    150 		place = EMSG;
    151 		++optind;
    152 	}
    153 	return (optopt);			/* return option letter */
    154 }
    155