1 /*
2  * Copyright 2002 Sun Microsystems, Inc.  All rights reserved.
3  * Use is subject to license terms.
4  */
5 
6 /*
7  * Copyright (c) 1991, 1993
8  *	The Regents of the University of California.  All rights reserved.
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 University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  */
38 
39 #ifndef lint
40 static char sccsid[] = "@(#)genget.c	8.1 (Berkeley) 6/4/93";
41 #endif /* not lint */
42 
43 #include <ctype.h>
44 #include <sys/types.h>
45 
46 #define	LOWER(x) (isupper(x) ? tolower(x) : (x))
47 
48 static char *ambiguous;		/* special return value for command routines */
49 
50 /*
51  * The prefix function returns 0 if *s1 is not a prefix
52  * of *s2.  If *s1 exactly matches *s2, the negative of
53  * the length is returned.  If *s1 is a prefix of *s2,
54  * the length of *s1 is returned.
55  */
56 int
isprefix(char * s1,char * s2)57 isprefix(char *s1, char *s2)
58 {
59 	char *os1;
60 	char c1, c2;
61 
62 	if (*s1 == '\0')
63 		return (-1);
64 	os1 = s1;
65 	c1 = *s1;
66 	c2 = *s2;
67 	while (LOWER(c1) == LOWER(c2)) {
68 		if (c1 == '\0')
69 			break;
70 		c1 = *++s1;
71 		c2 = *++s2;
72 	}
73 	return (*s1 ? 0 : (*s2 ? (s1 - os1) : (os1 - s1)));
74 }
75 
76 
77 /*
78  * Get an entry from the table, from what might be a prefix
79  *
80  * name		= name to match
81  * table	= name entry in table
82  */
83 char **
genget(char * name,char ** table,int stlen)84 genget(char *name, char **table, int stlen)
85 {
86 	register char **c, **found;
87 	register int n;
88 
89 	if (name == 0)
90 	    return (0);
91 
92 	found = 0;
93 	/*LINTED*/
94 	for (c = table; *c != NULL; c = (char **)((char *)c + stlen)) {
95 		if ((n = isprefix(name, *c)) == 0)
96 			continue;
97 		if (n < 0)		/* exact match */
98 			return (c);
99 		if (found)
100 			return (&ambiguous);
101 		found = c;
102 	}
103 	return (found);
104 }
105 
106 /*
107  * Function call version of Ambiguous()
108  */
109 boolean_t
Ambiguous(void * s)110 Ambiguous(void *s)
111 {
112 	return ((char **)s == &ambiguous);
113 }
114