/*	$OpenBSD: boot.c,v 1.18 2019/10/20 03:44:49 guenther Exp $ */

/*
 * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
 *
 * 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.
 *
 */

/*
 * IMPORTANT: any functions below are NOT protected by SSP.  Please
 * do not add anything except what is required to reach GOT with
 * an adjustment.
 */

#define	_DYN_LOADER

#include <sys/exec_elf.h>

#include "syscall.h"
#include "archdep.h"

#include "../../lib/csu/os-note-elf.h"

#if RELOC_TAG == DT_RELA
typedef	Elf_RelA	RELOC_TYPE;
# define RELOCATE_RELATIVE(w, r, b)	*(w) = (r)->r_addend + (b)
#elif RELOC_TAG == DT_REL
typedef	Elf_Rel		RELOC_TYPE;
# define RELOCATE_RELATIVE(w, r, b)	*(w) += (b)
#else
# error "unknown RELOC_TAG"
#endif

/*
 * Local decls.
 */
void _dl_boot_bind(const long, long *, Elf_Dyn *) __boot;

void
_dl_boot_bind(const long sp, long *dl_data, Elf_Dyn *dynp)
{
	AuxInfo		*auxstack;
	long		*stack;
	int		n, argc;
	char		**argv, **envp;
	long		loff;
	RELOC_TYPE	*dt_reloc;	/* DT_RELA   or DT_REL */
	Elf_Word	dt_relocsz;	/* DT_RELASZ or DT_RELSZ */
	RELOC_TYPE	*rend;

	/*
	 * Scan argument and environment vectors. Find dynamic
	 * data vector put after them.
	 */
	stack = (long *)sp;
	argc = *stack++;
	argv = (char **)stack;
	envp = &argv[argc + 1];
	stack = (long *)envp;
	while (*stack++ != 0L)
		;

	/*
	 * Zero out dl_data.
	 */
	for (n = 0; n <= AUX_entry; n++)
		dl_data[n] = 0;

	/*
	 * Dig out auxiliary data set up by exec call. Move all known
	 * tags to an indexed local table for easy access.
	 */
	for (auxstack = (AuxInfo *)stack; auxstack->au_id != AUX_null;
	    auxstack++) {
		if (auxstack->au_id > AUX_entry)
			continue;
		dl_data[auxstack->au_id] = auxstack->au_v;
	}
	loff = dl_data[AUX_base];	/* XXX assumes ld.so is linked at 0x0 */

	/*
	 * Scan the DYNAMIC section for the loader for the two items we need
	 */
	dt_reloc = NULL;
	dt_relocsz = 0;
	while (dynp->d_tag != DT_NULL) {
		if (dynp->d_tag == RELOC_TAG)		/* DT_{RELA,REL} */
			dt_reloc = (void *)(dynp->d_un.d_ptr + loff);
		else if (dynp->d_tag == RELOC_TAG+1)	/* DT_{RELA,REL}SZ */
			dt_relocsz = dynp->d_un.d_val;
		dynp++;
	}

	rend = (RELOC_TYPE *)((char *)dt_reloc + dt_relocsz);
	for (; dt_reloc < rend; dt_reloc++) {
		Elf_Addr *ra;

		ra = (Elf_Addr *)(dt_reloc->r_offset + loff);
		RELOCATE_RELATIVE(ra, dt_reloc, loff);
	}
}