1 | /* $NetBSD: strncpy.c,v 1.3 2007/06/04 18:19:28 christos Exp $ */ |
2 | |
3 | /*- |
4 | * Copyright (c) 1990, 1993 |
5 | * The Regents of the University of California. All rights reserved. |
6 | * |
7 | * This code is derived from software contributed to Berkeley by |
8 | * Chris Torek. |
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. Neither the name of the University nor the names of its contributors |
19 | * may be used to endorse or promote products derived from this software |
20 | * without specific prior written permission. |
21 | * |
22 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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 | |
35 | #include <sys/cdefs.h> |
36 | #if defined(LIBC_SCCS) && !defined(lint) |
37 | #if 0 |
38 | static char sccsid[] = "@(#)strncpy.c 8.1 (Berkeley) 6/4/93" ; |
39 | #else |
40 | __RCSID("$NetBSD: strncpy.c,v 1.3 2007/06/04 18:19:28 christos Exp $" ); |
41 | #endif |
42 | #endif /* LIBC_SCCS and not lint */ |
43 | |
44 | #if !defined(_KERNEL) && !defined(_STANDALONE) |
45 | #include <assert.h> |
46 | #include <string.h> |
47 | #else |
48 | #include <lib/libkern/libkern.h> |
49 | #endif |
50 | |
51 | #ifdef _FORTIFY_SOURCE |
52 | #undef strncpy |
53 | #endif |
54 | |
55 | /* |
56 | * Copy src to dst, truncating or null-padding to always copy n bytes. |
57 | * Return dst. |
58 | */ |
59 | char * |
60 | strncpy(char *dst, const char *src, size_t n) |
61 | { |
62 | |
63 | _DIAGASSERT(dst != NULL); |
64 | _DIAGASSERT(src != NULL); |
65 | |
66 | if (n != 0) { |
67 | char *d = dst; |
68 | const char *s = src; |
69 | |
70 | do { |
71 | if ((*d++ = *s++) == 0) { |
72 | /* NUL pad the remaining n-1 bytes */ |
73 | while (--n != 0) |
74 | *d++ = 0; |
75 | break; |
76 | } |
77 | } while (--n != 0); |
78 | } |
79 | return (dst); |
80 | } |
81 | |