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I visited telnet to find and fix some monster bug, and within 20 minutes
rediscovered that telnet has more more signal race conditions and trashing
of global state than all the rest of the openbsd source tree (where signal
races have either been fixed or marked with "XXX signal race".  I don't
feel like being a hero here today, so I'm fixing a whitespace error in an
unrelated file.

/*     $OpenBSD: genget.c,v 1.6 2019/07/11 05:11:16 deraadt Exp $  */

/*-
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/* $KTH: genget.c,v 1.6 1997/05/04 09:01:34 assar Exp $ */

#include <ctype.h>
#include "telnet_locl.h"

/*
 * The prefix function returns 0 if *s1 is not a prefix
 * of *s2.  If *s1 exactly matches *s2, the negative of
 * the length is returned.  If *s1 is a prefix of *s2,
 * the length of *s1 is returned.
 */
int
isprefix(char *s1, char *s2)
{
    char *os1;
    char c1, c2;

    if (*s1 == '\0')
	return(-1);
    os1 = s1;
    c1 = *s1;
    c2 = *s2;
    while (tolower((unsigned char)c1) == tolower((unsigned char)c2)) {
	if (c1 == '\0')
	    break;
	c1 = *++s1;
	c2 = *++s2;
    }
    return(*s1 ? 0 : (*s2 ? (s1 - os1) : (os1 - s1)));
}

static char *ambiguous;		/* special return value for command routines */

char **
genget(char *name, char **table, int stlen)
     /* name to match */
     /* name entry in table */
{
    char **c, **found;
    int n;

    if (name == NULL)
	return (NULL);

    found = NULL;
    for (c = table; *c != NULL; c = (char **)((char *)c + stlen)) {
	if ((n = isprefix(name, *c)) == 0)
	    continue;
	if (n < 0)		/* exact match */
	    return(c);
	if (found)
	    return(&ambiguous);
	found = c;
    }
    return(found);
}

/*
 * Function call version of Ambiguous()
 */
int
Ambiguous(void *s)
{
    return((char **)s == &ambiguous);
}