1 /* $OpenBSD: genget.c,v 1.6 2019/07/11 05:11:16 deraadt Exp $ */ 2 3 /*- 4 * Copyright (c) 1991, 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 /* $KTH: genget.c,v 1.6 1997/05/04 09:01:34 assar Exp $ */ 33 34 #include <ctype.h> 35 #include "telnet_locl.h" 36 37 /* 38 * The prefix function returns 0 if *s1 is not a prefix 39 * of *s2. If *s1 exactly matches *s2, the negative of 40 * the length is returned. If *s1 is a prefix of *s2, 41 * the length of *s1 is returned. 42 */ 43 int 44 isprefix(char *s1, char *s2) 45 { 46 char *os1; 47 char c1, c2; 48 49 if (*s1 == '\0') 50 return(-1); 51 os1 = s1; 52 c1 = *s1; 53 c2 = *s2; 54 while (tolower((unsigned char)c1) == tolower((unsigned char)c2)) { 55 if (c1 == '\0') 56 break; 57 c1 = *++s1; 58 c2 = *++s2; 59 } 60 return(*s1 ? 0 : (*s2 ? (s1 - os1) : (os1 - s1))); 61 } 62 63 static char *ambiguous; /* special return value for command routines */ 64 65 char ** 66 genget(char *name, char **table, int stlen) 67 /* name to match */ 68 /* name entry in table */ 69 { 70 char **c, **found; 71 int n; 72 73 if (name == NULL) 74 return (NULL); 75 76 found = NULL; 77 for (c = table; *c != NULL; c = (char **)((char *)c + stlen)) { 78 if ((n = isprefix(name, *c)) == 0) 79 continue; 80 if (n < 0) /* exact match */ 81 return(c); 82 if (found) 83 return(&ambiguous); 84 found = c; 85 } 86 return(found); 87 } 88 89 /* 90 * Function call version of Ambiguous() 91 */ 92 int 93 Ambiguous(void *s) 94 { 95 return((char **)s == &ambiguous); 96 } 97