/* $OpenBSD: elf2ecoff.c,v 1.6 2005/12/21 01:40:24 millert Exp $	 */
/* $NetBSD: elf2ecoff.c,v 1.8 1997/07/20 03:50:54 jonathan Exp $	 */

/*
 * Copyright (c) 1997 Jonathan Stone
 *    All rights reserved.
 * Copyright (c) 1995
 *	Ted Lemon (hereinafter referred to as the author)
 *
 * 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.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * 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.
 */

/*
 * elf2ecoff.c
 *
 * This program converts an elf executable to an ECOFF executable. No symbol
 * table is retained.   This is useful primarily in building net-bootable
 * kernels for machines (e.g., DECstation and Alpha) which only support the
 * ECOFF object file format.
 */

#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <elf_abi.h>
#include <machine/elf_abi.h>
#include <stdio.h>
#include <sys/exec_ecoff.h>
#include <errno.h>
#include <string.h>
#include <limits.h>

extern char    *__progname;

struct sect {
	unsigned long   vaddr;
	unsigned long   len;
};

int	phcmp();
char	*saveRead(int file, off_t offset, off_t len, char *name);
int	copy(int, int, off_t, off_t);
int	translate_syms(int, int, off_t, off_t, off_t, off_t);
int	*symTypeTable;

int
main(int argc, char *argv[])
{
	Elf32_Ehdr      ex;
	Elf32_Phdr     *ph;
	Elf32_Shdr     *sh;
	struct sym     *symtab;
	char	   *shstrtab;
	int	     strtabix, symtabix;
	int	     i, pad;
	struct sect     text, data, bss;
	struct ecoff_exechdr eh;
	struct ecoff_scnhdr esecs[3];
	int	     infile, outfile;
	unsigned long   cur_vma = ULONG_MAX;

	text.len = data.len = bss.len = 0;
	text.vaddr = data.vaddr = bss.vaddr = 0;

	/* Check args... */
	if (argc < 3 || argc > 4) {
usage:
		fprintf(stderr,
		    "usage: %s <elf executable> <ecoff executable>\n", __progname);
		exit(1);
	}
	/* Try the input file... */
	if ((infile = open(argv[1], O_RDONLY)) < 0) {
		fprintf(stderr, "Can't open %s for read: %s\n",
		    argv[1], strerror(errno));
		exit(1);
	}
	/* Read the header, which is at the beginning of the file... */
	i = read(infile, &ex, sizeof ex);
	if (i != sizeof ex) {
		fprintf(stderr, "ex: %s: %s.\n",
		    argv[1], i ? strerror(errno) : "End of file reached");
		exit(1);
	}
	/* Read the program headers... */
	ph = (Elf32_Phdr *) saveRead(infile, ex.e_phoff,
	ex.e_phnum * sizeof(Elf32_Phdr), "ph");
	/* Read the section headers... */
	sh = (Elf32_Shdr *) saveRead(infile, ex.e_shoff,
	    ex.e_shnum * sizeof(Elf32_Shdr), "sh");
	/* Read in the section string table. */
	shstrtab = saveRead(infile, sh[ex.e_shstrndx].sh_offset,
	    sh[ex.e_shstrndx].sh_size, "shstrtab");

	/*
	 * Figure out if we can cram the program header into an ECOFF
	 * header...  Basically, we can't handle anything but loadable
	 * segments, but we can ignore some kinds of segments.  We can't
	 * handle holes in the address space.  Segments may be out of order,
	 * so we sort them first.
	 */

	qsort(ph, ex.e_phnum, sizeof(Elf32_Phdr), phcmp);

	for (i = 0; i < ex.e_phnum; i++) {
		/* Section types we can ignore... */
		if (ph[i].p_type == PT_NULL || ph[i].p_type == PT_NOTE ||
		    ph[i].p_type == PT_PHDR || ph[i].p_type == PT_MIPS_REGINFO)
			continue;
		/* Section types we can't handle... */
		else if (ph[i].p_type != PT_LOAD) {
			fprintf(stderr,
			    "Program header %d type %d can't be converted.\n",
			    i, ph[i].p_type);
			exit(1);
		}
		/* Writable (data) segment? */
		if (ph[i].p_flags & PF_W) {
			struct sect     ndata, nbss;

			ndata.vaddr = ph[i].p_vaddr;
			ndata.len = ph[i].p_filesz;
			nbss.vaddr = ph[i].p_vaddr + ph[i].p_filesz;
			nbss.len = ph[i].p_memsz - ph[i].p_filesz;

			combine(&data, &ndata, 0);
			combine(&bss, &nbss, 1);
		} else {
			struct sect     ntxt;

			ntxt.vaddr = ph[i].p_vaddr;
			ntxt.len = ph[i].p_filesz;
			combine(&text, &ntxt);
		}
		/* Remember the lowest segment start address. */
		if (ph[i].p_vaddr < cur_vma)
			cur_vma = ph[i].p_vaddr;
	}

	/* Sections must be in order to be converted... */
	if (text.vaddr > data.vaddr || data.vaddr > bss.vaddr ||
	    text.vaddr + text.len > data.vaddr || data.vaddr + data.len > bss.vaddr) {
		fprintf(stderr, "Sections ordering prevents a.out conversion.\n");
		exit(1);
	}
	/*
	 * If there's a data section but no text section, then the loader
	 * combined everything into one section.   That needs to be the text
	 * section, so just make the data section zero length following text.
	 */
	if (data.len && !text.len) {
		text = data;
		data.vaddr = text.vaddr + text.len;
		data.len = 0;
	}
	/*
	 * If there is a gap between text and data, we'll fill it when we
	 * copy the data, so update the length of the text segment as
	 * represented in a.out to reflect that, since a.out doesn't allow
	 * gaps in the program address space.
	 */
	if (text.vaddr + text.len < data.vaddr)
		text.len = data.vaddr - text.vaddr;

	/* We now have enough information to cons up an a.out header... */
	eh.a.magic = ECOFF_OMAGIC;
	eh.a.vstamp = 200;
	eh.a.tsize = text.len;
	eh.a.dsize = data.len;
	eh.a.bsize = bss.len;
	eh.a.entry = ex.e_entry;
	eh.a.text_start = text.vaddr;
	eh.a.data_start = data.vaddr;
	eh.a.bss_start = bss.vaddr;
	eh.a.ea_gprmask = 0xf3fffffe;
	bzero(&eh.a.ea_cprmask, sizeof eh.a.ea_cprmask);
	eh.a.ea_gp_value = 0;	/* unused. */

	eh.f.f_magic = ECOFF_MAGIC_MIPSEL;
	eh.f.f_nscns = 3;
	eh.f.f_timdat = 0;	/* bogus */
	eh.f.f_symptr = 0;
	eh.f.f_nsyms = 0;
	eh.f.f_opthdr = sizeof eh.a;
	eh.f.f_flags = 0x100f;	/* Stripped, not sharable. */

	strlcpy(esecs[0].s_name, ".text", sizeof(esecs[0].s_name));
	strlcpy(esecs[1].s_name, ".data", sizeof(esecs[0].s_name));
	strlcpy(esecs[2].s_name, ".bss", sizeof(esecs[0].s_name));
	esecs[0].s_paddr = esecs[0].s_vaddr = eh.a.text_start;
	esecs[1].s_paddr = esecs[1].s_vaddr = eh.a.data_start;
	esecs[2].s_paddr = esecs[2].s_vaddr = eh.a.bss_start;
	esecs[0].s_size = eh.a.tsize;
	esecs[1].s_size = eh.a.dsize;
	esecs[2].s_size = eh.a.bsize;
	esecs[0].s_scnptr = ECOFF_TXTOFF(&eh);
	esecs[1].s_scnptr = ECOFF_DATOFF(&eh);
	esecs[2].s_scnptr = esecs[1].s_scnptr +
	    ECOFF_ROUND(esecs[1].s_size, ECOFF_SEGMENT_ALIGNMENT(&eh));
	esecs[0].s_relptr = esecs[1].s_relptr = esecs[2].s_relptr = 0;
	esecs[0].s_lnnoptr = esecs[1].s_lnnoptr = esecs[2].s_lnnoptr = 0;
	esecs[0].s_nreloc = esecs[1].s_nreloc = esecs[2].s_nreloc = 0;
	esecs[0].s_nlnno = esecs[1].s_nlnno = esecs[2].s_nlnno = 0;
	esecs[0].s_flags = 0x20;
	esecs[1].s_flags = 0x40;
	esecs[2].s_flags = 0x82;

	/* Make the output file... */
	if ((outfile = open(argv[2], O_WRONLY | O_CREAT, 0777)) < 0) {
		fprintf(stderr, "Unable to create %s: %s\n", argv[2], strerror(errno));
		exit(1);
	}
	/* Write the headers... */
	i = write(outfile, &eh.f, sizeof(struct ecoff_filehdr));
	if (i != sizeof(struct ecoff_filehdr)) {
		perror("efh: write");
		exit(1);

		for (i = 0; i < 6; i++) {
			printf("Section %d: %s phys %x  size %x  file offset %x\n",
			    i, esecs[i].s_name, esecs[i].s_paddr,
			    esecs[i].s_size, esecs[i].s_scnptr);
		}
	}
	fprintf(stderr, "wrote %d byte file header.\n", i);

	i = write(outfile, &eh.a, sizeof(struct ecoff_aouthdr));
	if (i != sizeof(struct ecoff_aouthdr)) {
		perror("eah: write");
		exit(1);
	}
	fprintf(stderr, "wrote %d byte a.out header.\n", i);

	i = write(outfile, &esecs, sizeof esecs);
	if (i != sizeof esecs) {
		perror("esecs: write");
		exit(1);
	}
	fprintf(stderr, "wrote %d bytes of section headers.\n", i);

	if (pad = ((sizeof eh + sizeof esecs) & 15)) {
		pad = 16 - pad;
		i = write(outfile, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0", pad);
		if (i < 0) {
			perror("ipad: write");
			exit(1);
		}
		fprintf(stderr, "wrote %d byte pad.\n", i);
	}
	/*
	 * Copy the loadable sections.   Zero-fill any gaps less than 64k;
	 * complain about any zero-filling, and die if we're asked to
	 * zero-fill more than 64k.
	 */
	for (i = 0; i < ex.e_phnum; i++) {
		/*
		 * Unprocessable sections were handled above, so just verify
		 * that the section can be loaded before copying.
		 */
		if (ph[i].p_type == PT_LOAD && ph[i].p_filesz) {
			if (cur_vma != ph[i].p_vaddr) {
				unsigned long   gap = ph[i].p_vaddr - cur_vma;
				char	    obuf[1024];
				if (gap > 65536) {
					fprintf(stderr,
					    "Intersegment gap (%d bytes) too large.\n",
					    gap);
					exit(1);
				}
				fprintf(stderr,
				    "Warning: %d byte intersegment gap.\n", gap);
				memset(obuf, 0, sizeof obuf);
				while (gap) {
					int count = write(outfile, obuf,
					    (gap > sizeof obuf
					    ? sizeof obuf : gap));
					if (count < 0) {
						fprintf(stderr,
						    "Error writing gap: %s\n",
						    strerror(errno));
						exit(1);
					}
					gap -= count;
				}
			}
			fprintf(stderr, "writing %d bytes...\n", ph[i].p_filesz);
			copy(outfile, infile, ph[i].p_offset, ph[i].p_filesz);
			cur_vma = ph[i].p_vaddr + ph[i].p_filesz;
		}
	}

	/*
	 * Write a page of padding for boot PROMS that read entire pages.
	 * Without this, they may attempt to read past the end of the
	 * data section, incur an error, and refuse to boot.
	 */
	{
		char	    obuf[4096];
		memset(obuf, 0, sizeof obuf);
		if (write(outfile, obuf, sizeof(obuf)) != sizeof(obuf)) {
			fprintf(stderr, "Error writing PROM padding: %s\n",
				strerror(errno));
			exit(1);
		}
	}

	/* Looks like we won... */
	exit(0);
}

void
copy(int out, int in, off_t offset, off_t size)
{
	char	    ibuf[4096];
	int	    remaining, cur, count;

	/* Go to the start of the ELF symbol table... */
	if (lseek(in, offset, SEEK_SET) < 0) {
		perror("copy: lseek");
		exit(1);
	}
	remaining = size;
	while (remaining) {
		cur = remaining;
		if (cur > sizeof ibuf)
			cur = sizeof ibuf;
		remaining -= cur;
		if ((count = read(in, ibuf, cur)) != cur) {
			fprintf(stderr, "copy: read: %s\n",
			 count ? strerror(errno) : "premature end of file");
			exit(1);
		}
		if ((count = write(out, ibuf, cur)) != cur) {
			perror("copy: write");
			exit(1);
		}
	}
}

/*
 * Combine two segments, which must be contiguous.   If pad is true, it's
 * okay for there to be padding between.
 */
void
combine(struct sect *base, struct sect *new, int pad)
{
	if (!base->len)
		*base = *new;
	else if (new->len) {
		if (base->vaddr + base->len != new->vaddr) {
			if (pad)
				base->len = new->vaddr - base->vaddr;
			else {
				fprintf(stderr,
				"Non-contiguous data can't be converted.\n");
				exit(1);
			}
		}
		base->len += new->len;
	}
}

int
phcmp(Elf32_Phdr *h1, Elf32_Phdr *h2)
{
	if (h1->p_vaddr > h2->p_vaddr)
		return 1;
	else if (h1->p_vaddr < h2->p_vaddr)
		return -1;
	else
		return 0;
}

char *
saveRead(int file, off_t offset, off_t len, char *name)
{
	char	   *tmp;
	int	     count;
	off_t	   off;

	if ((off = lseek(file, offset, SEEK_SET)) < 0) {
		fprintf(stderr, "%s: fseek: %s\n", name, strerror(errno));
		exit(1);
	}
	if (!(tmp = (char *) malloc(len))) {
		fprintf(stderr, "%s: Can't allocate %d bytes.\n", name, len);
		exit(1);
	}
	count = read(file, tmp, len);
	if (count != len) {
		fprintf(stderr, "%s: read: %s.\n",
		    name, count ? strerror(errno) : "End of file reached");
		exit(1);
	}
	return tmp;
}