xref: /freebsd/lib/libc/stdlib/getopt.c (revision 2e3f49888ec8851bafb22011533217487764fdb0)
1 /*	$NetBSD: getopt.c,v 1.29 2014/06/05 22:00:22 christos Exp $	*/
2 
3 /*-
4  * SPDX-License-Identifier: BSD-3-Clause
5  *
6  * Copyright (c) 1987, 1993, 1994
7  *	The Regents of the University of California.  All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include "namespace.h"
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <string.h>
38 #include <unistd.h>
39 #include "un-namespace.h"
40 
41 #include "libc_private.h"
42 
43 int	opterr = 1,		/* if error message should be printed */
44 	optind = 1,		/* index into parent argv vector */
45 	optopt,			/* character checked for validity */
46 	optreset;		/* reset getopt */
47 char	*optarg;		/* argument associated with option */
48 
49 #define	BADCH	(int)'?'
50 #define	BADARG	(int)':'
51 static char EMSG[] = "";
52 /*
53  * getopt --
54  *	Parse argc/argv argument vector.
55  */
56 int
57 getopt(int nargc, char * const nargv[], const char *ostr)
58 {
59 	static char *place = EMSG;		/* option letter processing */
60 	char *oli;				/* option letter list index */
61 
62 	if (optreset || *place == 0) {		/* update scanning pointer */
63 		optreset = 0;
64 		place = nargv[optind];
65 		if (optind >= nargc || *place++ != '-') {
66 			/* Argument is absent or is not an option */
67 			place = EMSG;
68 			return (-1);
69 		}
70 		optopt = *place++;
71 		if (optopt == '-' && *place == 0) {
72 			/* "--" => end of options */
73 			++optind;
74 			place = EMSG;
75 			return (-1);
76 		}
77 		if (optopt == 0) {
78 			/* Solitary '-', treat as a '-' option
79 			   if the program (eg su) is looking for it. */
80 			place = EMSG;
81 			if (strchr(ostr, '-') == NULL)
82 				return (-1);
83 			optopt = '-';
84 		}
85 	} else
86 		optopt = *place++;
87 
88 	/* See if option letter is one the caller wanted... */
89 	if (optopt == ':' || (oli = strchr(ostr, optopt)) == NULL) {
90 		if (*place == 0)
91 			++optind;
92 		if (opterr && *ostr != ':')
93 			(void)fprintf(stderr,
94 			    "%s: illegal option -- %c\n", _getprogname(),
95 			    optopt);
96 		return (BADCH);
97 	}
98 
99 	/* Does this option need an argument? */
100 	if (oli[1] != ':') {
101 		/* don't need argument */
102 		optarg = NULL;
103 		if (*place == 0)
104 			++optind;
105 	} else {
106 		/* Option-argument is either the rest of this argument or the
107 		   entire next argument. */
108 		if (*place)
109 			optarg = place;
110 		else if (oli[2] == ':')
111 			/*
112 			 * GNU Extension, for optional arguments if the rest of
113 			 * the argument is empty, we return NULL
114 			 */
115 			optarg = NULL;
116 		else if (nargc > ++optind)
117 			optarg = nargv[optind];
118 		else {
119 			/* option-argument absent */
120 			place = EMSG;
121 			if (*ostr == ':')
122 				return (BADARG);
123 			if (opterr)
124 				(void)fprintf(stderr,
125 				    "%s: option requires an argument -- %c\n",
126 				    _getprogname(), optopt);
127 			return (BADCH);
128 		}
129 		place = EMSG;
130 		++optind;
131 	}
132 	return (optopt);			/* return option letter */
133 }
134