/* $OpenBSD$ */
/*
 * Copyright (c) 2004 Dale Rahn <drahn@dalerahn.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * This program is a kludge to get around the broken objcopy which
 * will not correctly copy an i386 ELF kernel to a.out format for
 * pre 3.4 bootloader
 */
 
#include <sys/types.h>
#include <sys/exec_elf.h>
#include <sys/exec_aout.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <machine/param.h>
#include <fcntl.h>
#include <elf_abi.h>
#include <err.h>
#include <unistd.h>

extern char *__progname;

/*
 * these constants are i386 specific, if ported to additional architectures
 * this should be appropriately ifdef'd.
 */
#define KERNEL_MASK ~0xf0000000
#define KERNEL_SHIFT -0x00100000

int
main(int argc, char **argv)
{
	struct stat	sb;
	Elf_Ehdr	*ehdr;
	Elf_Phdr	*phdr;
	Elf_Shdr	*shdr;
	Elf_Addr	s;
	vaddr_t	max_file;
	vaddr_t	max_addr;
	vaddr_t	writeable_base;
	off_t		off;
	void		*sbase;
	int		sfd;
	int		dfd;
	int		i;
	struct	exec	aout;
	char		zero;

	if (argc != 3) {
		printf("USAGE: %s <src> <dst>", __progname);
		return 1;
	}

	sfd = open(argv[1], O_RDONLY, 0755);

	if (sfd == -1)
		err(1, "unable to open %s", argv[1]);

	if (fstat(sfd, &sb) < 0)
		err(2, "fstat");

	if (sb.st_size < sizeof (Elf_Ehdr))
		err(1, "truncated src file %s", argv[1]);

	sbase = mmap(0, sb.st_size, PROT_READ, MAP_FILE, sfd, 0);
	if (sbase == MAP_FAILED)
		err(1, "unable to mmap file %s", argv[1]);

	ehdr = (Elf_Ehdr *)sbase;

        phdr = (Elf_Phdr *)((char *)ehdr + ehdr->e_phoff);

	max_file = 0;
	max_addr= 0;
	for (i = 0; i < ehdr->e_phnum; i++) {
		switch (phdr[i].p_type) {
		case PT_LOAD:
		printf("looking at phdr %d %x, %x, %x, %x , %x ali %x\n",
	 		i,
			phdr[i].p_vaddr,  phdr[i].p_filesz,
			phdr[i].p_memsz,
			phdr[i].p_vaddr + phdr[i].p_filesz,
			phdr[i].p_vaddr + phdr[i].p_memsz,
			phdr[i].p_align
			);
			s =  phdr[i].p_vaddr + phdr[i].p_filesz;
			s += PAGE_MASK;
			s &= ~PAGE_MASK;
			s &= KERNEL_MASK;
			if (max_file < s)
				max_file = s;
			s =  phdr[i].p_vaddr + phdr[i].p_memsz;
			s += PAGE_MASK;
			s &= ~PAGE_MASK;
			s &= KERNEL_MASK;
			if (max_addr < s)
				max_addr = s;
			break;
		default:
			break;
		}
	}

	dfd = open(argv[2], O_CREAT|O_TRUNC|O_RDWR, 0755);
	if (dfd == -1)
		err(1, "unable to open %s for writing", argv[2]);

	printf("max file %x, max_addr %x\n", max_file, max_addr);
	off = max_file;
	if (lseek(dfd, off-1, SEEK_SET) != off-1)
		err(1, "lseek error on %s", argv[2]);

	zero = 0;
	if (write(dfd, &zero, 1) != 1)
		err(1, "write error on %s", argv[2]);

	for (i = 0; i < ehdr->e_phnum; i++) {
		switch (phdr[i].p_type) {
		case PT_LOAD:
			off = phdr[i].p_vaddr;
			off &= KERNEL_MASK;
			off += KERNEL_SHIFT;
			printf("writing to %llx, %x\n", off, phdr[i].p_filesz);
			if (lseek(dfd, off, SEEK_SET) != off)
				err(1, "lseek error on %s", argv[2]);
			if (write(dfd, sbase + phdr[i].p_offset,
			    phdr[i].p_filesz) != phdr[i].p_filesz)
				err(1, "write error on %s", argv[2]);
			break;
		default:
			break;
		}
	}
	off = 0;
	if (lseek(dfd, off, SEEK_SET) != off)
		err(1, "lseek error on %s", argv[2]);


        shdr = (Elf_Shdr *)((char *)ehdr + ehdr->e_shoff);
	for (i = 0; i < ehdr->e_shnum; i++) {
		if (shdr[i].sh_flags & SHF_EXECINSTR) {
			printf("looking at section %d %x %x\n", i,
			    shdr[i].sh_addr );
			writeable_base = (shdr[i].sh_addr + shdr[i].sh_size)
			    & ~PAGE_MASK;
			writeable_base &= KERNEL_MASK;
			break;
		}
	}

	printf("max file %x, max_addr %x writeable_base %x\n",
	max_file, max_addr, writeable_base);

	N_SETMAGIC(aout,ZMAGIC,MID_MACHINE,0);
	printf("aout.a_midmag %x\n", aout.a_midmag);
	aout.a_entry = ehdr->e_entry & KERNEL_MASK;
	printf("aout.a_entry %x\n", aout.a_entry);
	aout.a_text = writeable_base - (aout.a_entry & ~PAGE_MASK);
	printf("aout.a_text %x\n", aout.a_text);
	aout.a_data = max_file - writeable_base;
	printf("aout.a_data %x\n", aout.a_data);
	aout.a_bss = max_addr - max_file;
	printf("aout.a_bss %x\n", 
	aout.a_bss);
	aout.a_syms = 0;
	aout.a_trsize = 0;
	aout.a_drsize = 0;

	write(dfd, &aout, sizeof (aout));

	return 0;
}