xref: /illumos-gate/usr/src/boot/lib/libc/string/strncpy.c (revision 199767f8)
1*199767f8SToomas Soome /*-
2*199767f8SToomas Soome  * Copyright (c) 1990, 1993
3*199767f8SToomas Soome  *	The Regents of the University of California.  All rights reserved.
4*199767f8SToomas Soome  *
5*199767f8SToomas Soome  * This code is derived from software contributed to Berkeley by
6*199767f8SToomas Soome  * Chris Torek.
7*199767f8SToomas Soome  *
8*199767f8SToomas Soome  * Redistribution and use in source and binary forms, with or without
9*199767f8SToomas Soome  * modification, are permitted provided that the following conditions
10*199767f8SToomas Soome  * are met:
11*199767f8SToomas Soome  * 1. Redistributions of source code must retain the above copyright
12*199767f8SToomas Soome  *    notice, this list of conditions and the following disclaimer.
13*199767f8SToomas Soome  * 2. Redistributions in binary form must reproduce the above copyright
14*199767f8SToomas Soome  *    notice, this list of conditions and the following disclaimer in the
15*199767f8SToomas Soome  *    documentation and/or other materials provided with the distribution.
16*199767f8SToomas Soome  * 3. Neither the name of the University nor the names of its contributors
17*199767f8SToomas Soome  *    may be used to endorse or promote products derived from this software
18*199767f8SToomas Soome  *    without specific prior written permission.
19*199767f8SToomas Soome  *
20*199767f8SToomas Soome  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21*199767f8SToomas Soome  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22*199767f8SToomas Soome  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23*199767f8SToomas Soome  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24*199767f8SToomas Soome  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25*199767f8SToomas Soome  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26*199767f8SToomas Soome  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27*199767f8SToomas Soome  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28*199767f8SToomas Soome  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29*199767f8SToomas Soome  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30*199767f8SToomas Soome  * SUCH DAMAGE.
31*199767f8SToomas Soome  */
32*199767f8SToomas Soome 
33*199767f8SToomas Soome #if defined(LIBC_SCCS) && !defined(lint)
34*199767f8SToomas Soome static char sccsid[] = "@(#)strncpy.c	8.1 (Berkeley) 6/4/93";
35*199767f8SToomas Soome #endif /* LIBC_SCCS and not lint */
36*199767f8SToomas Soome #include <sys/cdefs.h>
37*199767f8SToomas Soome __FBSDID("$FreeBSD$");
38*199767f8SToomas Soome 
39*199767f8SToomas Soome #include <string.h>
40*199767f8SToomas Soome 
41*199767f8SToomas Soome /*
42*199767f8SToomas Soome  * Copy src to dst, truncating or null-padding to always copy n bytes.
43*199767f8SToomas Soome  * Return dst.
44*199767f8SToomas Soome  */
45*199767f8SToomas Soome char *
strncpy(char * __restrict dst,const char * __restrict src,size_t n)46*199767f8SToomas Soome strncpy(char * __restrict dst, const char * __restrict src, size_t n)
47*199767f8SToomas Soome {
48*199767f8SToomas Soome 	if (n != 0) {
49*199767f8SToomas Soome 		char *d = dst;
50*199767f8SToomas Soome 		const char *s = src;
51*199767f8SToomas Soome 
52*199767f8SToomas Soome 		do {
53*199767f8SToomas Soome 			if ((*d++ = *s++) == '\0') {
54*199767f8SToomas Soome 				/* NUL pad the remaining n-1 bytes */
55*199767f8SToomas Soome 				while (--n != 0)
56*199767f8SToomas Soome 					*d++ = '\0';
57*199767f8SToomas Soome 				break;
58*199767f8SToomas Soome 			}
59*199767f8SToomas Soome 		} while (--n != 0);
60*199767f8SToomas Soome 	}
61*199767f8SToomas Soome 	return (dst);
62*199767f8SToomas Soome }
63