xref: /netbsd-src/common/lib/libc/stdlib/getopt.c (revision f77396c90347ac2cf626f1ad822fbb0db8a8b11e)
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
getopt(int nargc,char * const nargv[],const char * ostr)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