strvalid.c revision 90819 
1/*-
2 * Copyright (c) 2002 Networks Associates Technologies, Inc.
3 * All rights reserved.
4 *
5 * This software was developed for the FreeBSD Project by NAI Labs,
6 * the Security Research Division of Network Associates, Inc. under
7 * DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA
8 * CHATS research program.
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. The names of the authors may not be used to endorse or promote
19 *    products derived from this software without specific prior written
20 *    permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * $FreeBSD: head/sys/libkern/strvalid.c 90819 2002-02-18 00:37:03Z rwatson $
35 */
36
37#include <sys/types.h>
38#include <sys/libkern.h>
39
40/*
41 * Return (1) if the buffer pointed to by kernel pointer 'buffer' and
42 * of length 'bufferlen' contains a valid NUL-terminated string
43 */
44int
45strvalid(const char *buffer, size_t bufferlen)
46{
47	int i;
48
49	/* Must be NUL-terminated. */
50	for (i = 0; i < bufferlen; i++)
51		if (buffer[i] == '\0')
52			return (1);
53
54	return (0);
55}
56