1 /* $OpenBSD: ap_cpystrn.c,v 1.7 2005/06/20 12:23:22 robert Exp $ */
2 
3 /* ====================================================================
4  * The Apache Software License, Version 1.1
5  *
6  * Copyright (c) 2000-2003 The Apache Software Foundation.  All rights
7  * reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  *
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in
18  *    the documentation and/or other materials provided with the
19  *    distribution.
20  *
21  * 3. The end-user documentation included with the redistribution,
22  *    if any, must include the following acknowledgment:
23  *       "This product includes software developed by the
24  *        Apache Software Foundation (http://www.apache.org/)."
25  *    Alternately, this acknowledgment may appear in the software itself,
26  *    if and wherever such third-party acknowledgments normally appear.
27  *
28  * 4. The names "Apache" and "Apache Software Foundation" must
29  *    not be used to endorse or promote products derived from this
30  *    software without prior written permission. For written
31  *    permission, please contact apache@apache.org.
32  *
33  * 5. Products derived from this software may not be called "Apache",
34  *    nor may "Apache" appear in their name, without prior written
35  *    permission of the Apache Software Foundation.
36  *
37  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
38  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
39  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
40  * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
41  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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43  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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45  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
46  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
47  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
48  * SUCH DAMAGE.
49  * ====================================================================
50  *
51  * This software consists of voluntary contributions made by many
52  * individuals on behalf of the Apache Software Foundation.  For more
53  * information on the Apache Software Foundation, please see
54  * <http://www.apache.org/>.
55  *
56  * Portions of this software are based upon public domain software
57  * originally written at the National Center for Supercomputing Applications,
58  * University of Illinois, Urbana-Champaign.
59  */
60 
61 #include "httpd.h"
62 
63 /*
64  * Apache's "replacement" for the strncpy() function. We roll our
65  * own to implement these specific changes:
66  *   (1) strncpy() doesn't always null terminate and we want it to.
67  *   (2) strncpy() null fills, which is bogus, esp. when copy 8byte
68  *       strings into 8k blocks.
69  *   (3) Instead of returning the pointer to the beginning of
70  *       the destination string, we return a pointer to the
71  *       terminating '\0' to allow us to "check" for truncation
72  *
73  * ap_cpystrn() follows the same call structure as strncpy().
74  */
75 
76 API_EXPORT(char *)
ap_cpystrn(char * dst,const char * src,size_t dst_size)77 ap_cpystrn(char *dst, const char *src, size_t dst_size)
78 {
79 
80 	char *d, *end;
81 
82 	if (!dst_size)
83 		return (dst);
84 
85 	d = dst;
86 	end = dst + dst_size - 1;
87 
88 	for (; d < end; ++d, ++src)
89 		if (!(*d = *src))
90 			return (d);
91 
92 	*d = '\0';      /* always null terminate */
93 
94 	return (d);
95 }
96