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getopt.c revision 1.1 
      1 /*	$NetBSD: getopt.c,v 1.1 2024/06/29 07:55:05 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 1.1 2024/06/29 07:55:05 rin Exp $");
     34 
     35 #include "namespace.h"
     36 
     37 #include <assert.h>
     38 #include <errno.h>
     39 #include <stdio.h>
     40 #include <stdlib.h>
     41 #include <string.h>
     42 #include <unistd.h>
     43 
     44 #ifdef __weak_alias
     45 __weak_alias(getopt,_getopt)
     46 #endif
     47 
     48 int	opterr = 1,		/* if error message should be printed */
     49 	optind = 1,		/* index into parent argv vector */
     50 	optopt,			/* character checked for validity */
     51 	optreset;		/* reset getopt */
     52 char	*optarg;		/* argument associated with option */
     53 
     54 #define	BADCH	(int)'?'
     55 #define	BADARG	(int)':'
     56 #define	EMSG	""
     57 
     58 /*
     59  * getopt --
     60  *	Parse argc/argv argument vector.
     61  */
     62 int
     63 getopt(int nargc, char * const nargv[], const char *ostr)
     64 {
     65 	static const char *place = EMSG;	/* option letter processing */
     66 	const char *oli;			/* option letter list index */
     67 
     68 	_DIAGASSERT(nargv != NULL);
     69 	_DIAGASSERT(ostr != NULL);
     70 
     71 	if (optreset || *place == 0) {		/* update scanning pointer */
     72 		optreset = 0;
     73 		place = nargv[optind];
     74 		if (optind >= nargc || *place++ != '-') {
     75 			/* Argument is absent or is not an option */
     76 			place = EMSG;
     77 			return (-1);
     78 		}
     79 		optopt = *place++;
     80 		if (optopt == '-' && *place == 0) {
     81 			/* "--" => end of options */
     82 			++optind;
     83 			place = EMSG;
     84 			return (-1);
     85 		}
     86 		if (optopt == 0) {
     87 			/* Solitary '-', treat as a '-' option
     88 			   if the program (eg su) is looking for it. */
     89 			place = EMSG;
     90 			if (strchr(ostr, '-') == NULL)
     91 				return -1;
     92 			optopt = '-';
     93 		}
     94 	} else
     95 		optopt = *place++;
     96 
     97 	/* See if option letter is one the caller wanted... */
     98 	if (optopt == ':' || (oli = strchr(ostr, optopt)) == NULL) {
     99 		if (*place == 0)
    100 			++optind;
    101 		if (opterr && *ostr != ':')
    102 			(void)fprintf(stderr,
    103 			    "%s: unknown option -- %c\n", getprogname(),
    104 			    optopt);
    105 		return (BADCH);
    106 	}
    107 
    108 	/* Does this option need an argument? */
    109 	if (oli[1] != ':') {
    110 		/* don't need argument */
    111 		optarg = NULL;
    112 		if (*place == 0)
    113 			++optind;
    114 	} else {
    115 		/* Option-argument is either the rest of this argument or the
    116 		   entire next argument. */
    117 		if (*place)
    118 			optarg = __UNCONST(place);
    119 		else if (oli[2] == ':')
    120 			/*
    121 			 * GNU Extension, for optional arguments if the rest of
    122 			 * the argument is empty, we return NULL
    123 			 */
    124 			optarg = NULL;
    125 		else if (nargc > ++optind)
    126 			optarg = nargv[optind];
    127 		else {
    128 			/* option-argument absent */
    129 			place = EMSG;
    130 			if (*ostr == ':')
    131 				return (BADARG);
    132 			if (opterr)
    133 				(void)fprintf(stderr,
    134 				    "%s: option requires an argument -- %c\n",
    135 				    getprogname(), optopt);
    136 			return (BADCH);
    137 		}
    138 		place = EMSG;
    139 		++optind;
    140 	}
    141 	return (optopt);			/* return option letter */
    142 }
    143