xref: /netbsd-src/sys/kern/subr_optstr.c (revision d48f14661dda8638fee055ba15d35bdfb29b9fa8)
1 /*	$NetBSD: subr_optstr.c,v 1.1 2006/02/03 11:04:46 jmmv Exp $	*/
2 
3 /*-
4  * Copyright (c) 2006 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Julio M. Merino Vidal.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the NetBSD
21  *	Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 #include <sys/cdefs.h>
40 __KERNEL_RCSID(0, "$NetBSD: subr_optstr.c,v 1.1 2006/02/03 11:04:46 jmmv Exp $");
41 
42 #include <sys/param.h>
43 #include <sys/optstr.h>
44 
45 /* --------------------------------------------------------------------- */
46 
47 /*
48  * Given an options string of the form 'a=b c=d ... y=z' and a key,
49  * looks for the given key's value in the string and returns it in buf
50  * with a maximum of bufsize bytes.  If the key is found, returns TRUE;
51  * otherwise FALSE.
52  */
53 boolean_t
54 optstr_get(const char *optstr, const char *key, char *buf, size_t bufsize)
55 {
56 	boolean_t found;
57 	const char *keyp;
58 
59 	found = FALSE;
60 
61 	/* Skip any initial spaces until we find a word. */
62 	while (*optstr == ' ' && *optstr != '\0')
63 		optstr++;
64 
65 	/* Search for the given key within the option string. */
66 	while (!found && *optstr != '\0') {
67 		/* Check if the next word matches the key. */
68 		keyp = key;
69 		while (*optstr == *keyp) {
70 			optstr++;
71 			keyp++;
72 		}
73 
74 		if (*optstr == '=')
75 			found = TRUE;
76 		else {
77 			/* Key not found; skip until next space. */
78 			while (*optstr != ' ' && *optstr != '\0')
79 				optstr++;
80 
81 			/* And now skip until next word. */
82 			while (*optstr == ' ' && *optstr != '\0')
83 				optstr++;
84 		}
85 	}
86 
87 	/* If the key was found; copy its value to the target buffer. */
88 	if (found) {
89 		const char *lastbuf;
90 
91 		lastbuf = buf + (bufsize - 1);
92 
93 		found = TRUE;
94 		optstr++; /* Skip '='. */
95 		while (buf != lastbuf && *optstr != ' ' && *optstr != '\0')
96 			*buf++ = *optstr++;
97 		*buf = '\0';
98 	}
99 
100 	return found;
101 }
102