usr/src/cmd/cmd-inet/usr.bin/telnet/genget.c

   1 /*
   2  * Copyright 2002 Sun Microsystems, Inc.  All rights reserved.
   3  * Use is subject to license terms.
   4  */
   5
   6 #pragma ident   "%Z%%M% %I%     %E% SMI"
   7
   8 /*
   9  * Copyright (c) 1991, 1993
  10  *      The Regents of the University of California.  All rights reserved.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. All advertising materials mentioning features or use of this software
  21  *    must display the following acknowledgement:
  22  *      This product includes software developed by the University of
  23  *      California, Berkeley and its contributors.
  24  * 4. Neither the name of the University nor the names of its contributors
  25  *    may be used to endorse or promote products derived from this software
  26  *    without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38  * SUCH DAMAGE.
  39  */
  40
  41 #ifndef lint
  42 static char sccsid[] = "@(#)genget.c    8.1 (Berkeley) 6/4/93";
  43 #endif /* not lint */
  44
  45 #include <ctype.h>
  46 #include <sys/types.h>
  47
  48 #define LOWER(x) (isupper(x) ? tolower(x) : (x))
  49
  50 static char *ambiguous;         /* special return value for command routines */
  51
  52 /*
  53  * The prefix function returns 0 if *s1 is not a prefix
  54  * of *s2.  If *s1 exactly matches *s2, the negative of
  55  * the length is returned.  If *s1 is a prefix of *s2,
  56  * the length of *s1 is returned.
  57  */
  58 int
  59 isprefix(char *s1, char *s2)
  60 {
  61         char *os1;
  62         char c1, c2;
  63
  64         if (*s1 == '\0')
  65                 return (-1);
  66         os1 = s1;
  67         c1 = *s1;
  68         c2 = *s2;
  69         while (LOWER(c1) == LOWER(c2)) {
  70                 if (c1 == '\0')
  71                         break;
  72                 c1 = *++s1;
  73                 c2 = *++s2;
  74         }
  75         return (*s1 ? 0 : (*s2 ? (s1 - os1) : (os1 - s1)));
  76 }
  77
  78
  79 /*
  80  * Get an entry from the table, from what might be a prefix
  81  *
  82  * name         = name to match
  83  * table        = name entry in table
  84  */
  85 char **
  86 genget(char *name, char **table, int stlen)
  87 {
  88         register char **c, **found;
  89         register int n;
  90
  91         if (name == 0)
  92             return (0);
  93
  94         found = 0;
  95         /*LINTED*/
  96         for (c = table; *c != NULL; c = (char **)((char *)c + stlen)) {
  97                 if ((n = isprefix(name, *c)) == 0)
  98                         continue;
  99                 if (n < 0)              /* exact match */
 100                         return (c);
 101                 if (found)
 102                         return (&ambiguous);
 103                 found = c;
 104         }
 105         return (found);
 106 }
 107
 108 /*
 109  * Function call version of Ambiguous()
 110  */
 111 boolean_t
 112 Ambiguous(void *s)
 113 {
 114         return ((char **)s == &ambiguous);
 115 }