libpe_utils.c

/*-
 * Copyright (c) 2016 Kai Wang
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <assert.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>

#include "_libpe.h"

ELFTC_VCSID("$Id: libpe_utils.c 3312 2016-01-10 09:23:51Z kaiwang27 $");

off_t
libpe_align(PE *pe, off_t off, size_t align)
{
	off_t n;

	assert(align > 0 && (align & (align - 1)) == 0);

	n = roundup(off, align);
	if (n > off) {
		if (libpe_pad(pe, n - off) < 0)
			return (-1);
	}

	return (n);
}

int
libpe_pad(PE *pe, size_t pad)
{
	char tmp[128];
	size_t s;

	memset(tmp, 0, sizeof(tmp));
	for (; pad > 0; pad -= s) {
		s = pad > sizeof(tmp) ? sizeof(tmp) : pad;
		if (write(pe->pe_fd, tmp, s) != (ssize_t) s) {
			errno = EIO;
			return (-1);
		}
	}

	return (0);
}