xref: /freebsd/lib/libc/stdlib/getsubopt.c (revision 397e83df75e0fcd0d3fcb95ae4d794cb7600fc89)
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 #include <stdlib.h>
33 #include <string.h>
34 
35 /*
36  * The SVID interface to getsubopt provides no way of figuring out which
37  * part of the suboptions list wasn't matched.  This makes error messages
38  * tricky...  The extern variable suboptarg is a pointer to the token
39  * which didn't match.
40  */
41 char *suboptarg;
42 
43 int
44 getsubopt(char **optionp, char * const *tokens, char **valuep)
45 {
46 	int cnt;
47 	char *p;
48 
49 	suboptarg = *valuep = NULL;
50 
51 	if (!optionp || !*optionp)
52 		return(-1);
53 
54 	/* skip leading white-space, commas */
55 	for (p = *optionp; *p && (*p == ',' || *p == ' ' || *p == '\t'); ++p);
56 
57 	if (!*p) {
58 		*optionp = p;
59 		return(-1);
60 	}
61 
62 	/* save the start of the token, and skip the rest of the token. */
63 	for (suboptarg = p;
64 	    *++p && *p != ',' && *p != '=' && *p != ' ' && *p != '\t';);
65 
66 	if (*p) {
67 		/*
68 		 * If there's an equals sign, set the value pointer, and
69 		 * skip over the value part of the token.  Terminate the
70 		 * token.
71 		 */
72 		if (*p == '=') {
73 			*p = '\0';
74 			for (*valuep = ++p;
75 			    *p && *p != ',' && *p != ' ' && *p != '\t'; ++p);
76 			if (*p)
77 				*p++ = '\0';
78 		} else
79 			*p++ = '\0';
80 		/* Skip any whitespace or commas after this token. */
81 		for (; *p && (*p == ',' || *p == ' ' || *p == '\t'); ++p);
82 	}
83 
84 	/* set optionp for next round. */
85 	*optionp = p;
86 
87 	for (cnt = 0; *tokens; ++tokens, ++cnt)
88 		if (!strcmp(suboptarg, *tokens))
89 			return(cnt);
90 	return(-1);
91 }
92