usr/src/lib/libc/port/gen/stpncpy.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
  24  */
  25
  26 /*      Copyright (c) 1988 AT&T */
  27 /*        All Rights Reserved   */
  28
  29 #include "lint.h"
  30 #include <string.h>
  31 #include <sys/types.h>
  32
  33 /*
  34  * Copy s2 to s1, truncating or null-padding to always copy n bytes
  35  * return a pointer to the terminating null byte in s1, or,
  36  * if s1 is not null-terminated, s1 + n.
  37  */
  38 char *
  39 stpncpy(char *_RESTRICT_KYWD s1, const char *_RESTRICT_KYWD s2, size_t n)
  40 {
  41         size_t len = strnlen(s2, n);
  42
  43         (void) strncpy(s1, s2, n);
  44
  45         return ((len < n) ? s1 + len : s1 + n);
  46 }