APACHE_1_3_42/src/ap/ap_cpystrn.c

/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "httpd.h"

/*
 * Apache's "replacement" for the strncpy() function. We roll our
 * own to implement these specific changes:
 *   (1) strncpy() doesn't always null terminate and we want it to.
 *   (2) strncpy() null fills, which is bogus, esp. when copy 8byte
 *       strings into 8k blocks.
 *   (3) Instead of returning the pointer to the beginning of
 *       the destination string, we return a pointer to the
 *       terminating '\0' to allow us to "check" for truncation
 *
 * ap_cpystrn() follows the same call structure as strncpy().
 */

API_EXPORT(char *) ap_cpystrn(char *dst, const char *src, size_t dst_size)
{

    char *d, *end;

    if (!dst_size)
        return (dst);

    d = dst;
    end = dst + dst_size - 1;

    for (; d < end; ++d, ++src) {
	if (!(*d = *src)) {
	    return (d);
	}
    }

    *d = '\0';	/* always null terminate */

    return (d);
}