xref: /freebsd/lib/libc/stdlib/getsubopt.c (revision bdd1243df58e60e85101c09001d9812a789b6bc4)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1990, 1993
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 #if defined(LIBC_SCCS) && !defined(lint)
33 static char sccsid[] = "@(#)getsubopt.c	8.1 (Berkeley) 6/4/93";
34 #endif /* LIBC_SCCS and not lint */
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #include <stdlib.h>
39 #include <string.h>
40 
41 /*
42  * The SVID interface to getsubopt provides no way of figuring out which
43  * part of the suboptions list wasn't matched.  This makes error messages
44  * tricky...  The extern variable suboptarg is a pointer to the token
45  * which didn't match.
46  */
47 char *suboptarg;
48 
49 int
50 getsubopt(char **optionp, char * const *tokens, char **valuep)
51 {
52 	int cnt;
53 	char *p;
54 
55 	suboptarg = *valuep = NULL;
56 
57 	if (!optionp || !*optionp)
58 		return(-1);
59 
60 	/* skip leading white-space, commas */
61 	for (p = *optionp; *p && (*p == ',' || *p == ' ' || *p == '\t'); ++p);
62 
63 	if (!*p) {
64 		*optionp = p;
65 		return(-1);
66 	}
67 
68 	/* save the start of the token, and skip the rest of the token. */
69 	for (suboptarg = p;
70 	    *++p && *p != ',' && *p != '=' && *p != ' ' && *p != '\t';);
71 
72 	if (*p) {
73 		/*
74 		 * If there's an equals sign, set the value pointer, and
75 		 * skip over the value part of the token.  Terminate the
76 		 * token.
77 		 */
78 		if (*p == '=') {
79 			*p = '\0';
80 			for (*valuep = ++p;
81 			    *p && *p != ',' && *p != ' ' && *p != '\t'; ++p);
82 			if (*p)
83 				*p++ = '\0';
84 		} else
85 			*p++ = '\0';
86 		/* Skip any whitespace or commas after this token. */
87 		for (; *p && (*p == ',' || *p == ' ' || *p == '\t'); ++p);
88 	}
89 
90 	/* set optionp for next round. */
91 	*optionp = p;
92 
93 	for (cnt = 0; *tokens; ++tokens, ++cnt)
94 		if (!strcmp(suboptarg, *tokens))
95 			return(cnt);
96 	return(-1);
97 }
98