xref: /freebsd/lib/libc/stdlib/getsubopt.c (revision 2008043f386721d58158e37e0d7e50df8095942d)
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 <stdlib.h>
36 #include <string.h>
37 
38 /*
39  * The SVID interface to getsubopt provides no way of figuring out which
40  * part of the suboptions list wasn't matched.  This makes error messages
41  * tricky...  The extern variable suboptarg is a pointer to the token
42  * which didn't match.
43  */
44 char *suboptarg;
45 
46 int
47 getsubopt(char **optionp, char * const *tokens, char **valuep)
48 {
49 	int cnt;
50 	char *p;
51 
52 	suboptarg = *valuep = NULL;
53 
54 	if (!optionp || !*optionp)
55 		return(-1);
56 
57 	/* skip leading white-space, commas */
58 	for (p = *optionp; *p && (*p == ',' || *p == ' ' || *p == '\t'); ++p);
59 
60 	if (!*p) {
61 		*optionp = p;
62 		return(-1);
63 	}
64 
65 	/* save the start of the token, and skip the rest of the token. */
66 	for (suboptarg = p;
67 	    *++p && *p != ',' && *p != '=' && *p != ' ' && *p != '\t';);
68 
69 	if (*p) {
70 		/*
71 		 * If there's an equals sign, set the value pointer, and
72 		 * skip over the value part of the token.  Terminate the
73 		 * token.
74 		 */
75 		if (*p == '=') {
76 			*p = '\0';
77 			for (*valuep = ++p;
78 			    *p && *p != ',' && *p != ' ' && *p != '\t'; ++p);
79 			if (*p)
80 				*p++ = '\0';
81 		} else
82 			*p++ = '\0';
83 		/* Skip any whitespace or commas after this token. */
84 		for (; *p && (*p == ',' || *p == ' ' || *p == '\t'); ++p);
85 	}
86 
87 	/* set optionp for next round. */
88 	*optionp = p;
89 
90 	for (cnt = 0; *tokens; ++tokens, ++cnt)
91 		if (!strcmp(suboptarg, *tokens))
92 			return(cnt);
93 	return(-1);
94 }
95