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For open/openat, if the flags parameter does not contain O_CREAT, the
3rd (variadic) mode_t parameter is irrelevant.  Many developers in the past
have passed mode_t (0, 044, 0644, or such), which might lead future people
to copy this broken idiom, and perhaps even believe this parameter has some
meaning or implication or application. Delete them all.
This comes out of a conversation where tb@ noticed that a strange (but
intentional) pledge behaviour is to always knock-out high-bits from
mode_t on a number of system calls as a safety factor, and his bewilderment
that this appeared to be happening against valid modes (at least visually),
but no sorry, they are all irrelevant junk.  They could all be 0xdeafbeef.
ok millert

/*	$OpenBSD: exec_elf.c,v 1.18 2021/10/24 21:24:18 deraadt Exp $ */

/*
 * Copyright (c) 1999 Mats O Jansson.  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 ``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 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/types.h>
#include <sys/exec.h>

#include <elf.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <nlist.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include "ukc.h"
#include "config.h"
#include "exec.h"

caddr_t		ptr, rest, pre;
Elf_Ehdr	elf_ex;
Elf_Phdr	*elf_phdr;
Elf_Shdr	*elf_shdr;
char		*elf_total;
char		*elf_shstrtab;
off_t		elf_size;

caddr_t
adjust(caddr_t x)
{
	int i;
	Elf_Shdr *s;
	unsigned long y = 0;

	s = elf_shdr;

	for (i = 0; i < elf_ex.e_shnum; i++) {
		if (s[i].sh_addr == 0)
			continue;
		if (((unsigned long)x >= s[i].sh_addr) &&
		    ((unsigned long)x < (s[i].sh_addr+s[i].sh_size))) {
			y = (unsigned long)&elf_total[(unsigned long)x -
			    s[i].sh_addr + s[i].sh_offset];
			break;
		}
	}

	return((caddr_t)y);
}

caddr_t
readjust(caddr_t x)
{
	int i;
	Elf_Shdr *s;
	unsigned long y = 0;

	s = elf_shdr;

	for (i = 0; i < elf_ex.e_shnum; i++) {
		if (s[i].sh_addr == 0)
			continue;
		if (((x - elf_total) >= s[i].sh_offset) &&
		    ((x - elf_total) <= (s[i].sh_offset + s[i].sh_size)))
			y = (unsigned long)x - (unsigned long)elf_total +
			    (unsigned long)s[i].sh_addr - s[i].sh_offset;
	}

	return((caddr_t)y);
}

void
loadkernel(char *file)
{
	int fd;

	if ((fd = open(file, O_RDONLY | O_EXLOCK)) == -1)
		err(1, "%s", file);

	if (read(fd, (char *)&elf_ex, sizeof(elf_ex)) != sizeof(elf_ex))
		errx(1, "can't read elf header");

	if (!IS_ELF(elf_ex))
		errx(1, "bad elf magic");

	elf_size = lseek(fd, (off_t)0, SEEK_END);
	(void)lseek(fd, (off_t)0, SEEK_SET);
	elf_total = emalloc((size_t)elf_size);

	if (read(fd, elf_total, (size_t)elf_size) != elf_size)
		errx(1, "can't read elf kernel");

	if (elf_ex.e_phoff > (size_t)elf_size)
		errx(1, "incorrect ELF header or truncated file");
	if (elf_ex.e_shoff > (size_t)elf_size)
		errx(1, "incorrect ELF header or truncated file");

	elf_phdr = (Elf_Phdr *)&elf_total[elf_ex.e_phoff];
	elf_shdr = (Elf_Shdr *)&elf_total[elf_ex.e_shoff];

	if ((char *)&elf_shdr[elf_ex.e_shstrndx] +
	    sizeof(elf_shdr[elf_ex.e_shstrndx]) >= elf_total + (size_t)elf_size)
		errx(1, "incorrect ELF header or truncated file");

	if ((char *)&elf_shdr[elf_ex.e_shstrndx].sh_offset +
	    sizeof(elf_shdr[elf_ex.e_shstrndx].sh_offset) >=
	    elf_total + (size_t)elf_size)
		errx(1, "incorrect ELF header or truncated file");

	elf_shstrtab = &elf_total[elf_shdr[elf_ex.e_shstrndx].sh_offset];

	close(fd);
}

void
savekernel(char *outfile)
{
	int fd;

	if ((fd = open(outfile, O_WRONLY | O_CREAT | O_TRUNC, 0700)) == -1)
		err(1, "%s", outfile);

	if (write(fd, elf_total, (size_t)elf_size) != elf_size)
		errx(1, "can't write file %s", outfile);

	close(fd);
}