/*****************************************************************************/

/*  pemagination: a (virtual) tour into portable bits and executable bytes   */

/*  Copyright (C) 2013--2020  SysDeer Technologies, LLC                      */

/*  Released under GPLv2 and GPLv3; see COPYING.PEMAGINE.                    */

/*****************************************************************************/

#include <psxtypes/psxtypes.h>

#include <pemagine/pe_consts.h>

#include <pemagine/pe_structs.h>

#include <pemagine/pemagine.h>

#include "pe_impl.h"

static __inline__ int pe_addr_within_bounds(void * addr, void * bottom, void * top)

{

	return (((uintptr_t)addr >= (uintptr_t)bottom) && ((uintptr_t)addr < (uintptr_t)top));

}

static void * pe_resolve_forwarder_rva(char * forwarder)

{

	uint16_t	soname[512];

	uint16_t *	wch;

	char *		mark;

	char *		dot;

	void *		base;

	for (mark=forwarder; *mark; mark++)

		(void)0;

	if (mark - forwarder + 5 > 512)

		return 0;

	for (dot=&mark[-1]; dot>forwarder && *dot!='.'; dot--)

		(void)0;

	if (*dot != '.')

		return 0;

	mark = forwarder;

	wch  = soname;

	for (; mark

		*wch++ = *mark++;

	if (mark < dot)

		return 0;

	*wch++ = '.';

	*wch++ = 'd';

	*wch++ = 'l';

	*wch++ = 'l';

	*wch++ = 0;

	if (!(base = pe_get_module_handle(soname)))

		return 0;

	return pe_get_procedure_address(base,++dot);

}

int pe_get_export_symbol_info(

	const void *		base,

	const char *		name,

	struct pe_export_sym *	sym)

{

	struct pe_raw_export_hdr * exp_hdr;

	ssize_t		len;

	uint32_t *	rva_offset;

	uintptr_t *	addr_offset;

	uintptr_t	addr;

	uint32_t	sec_size;

	void *		sec_addr_cap;

	uint32_t *	fn_addr;

	uint32_t *	fn_names;

	uint16_t *	fn_ordinals;

	uint32_t *	addr_entries;

	uint32_t *	name_entries;

	char *		exp_name;

	const char *	src;

	const char *	dst;

	ssize_t		match;

	uint32_t	lower;

	uint32_t	upper;

	uint32_t	idx;

	/* init */

	sym->ordinal_base	= 0;

	sym->ordinal		= 0;

	sym->addr		= 0;

	sym->forwarder_rva	= 0;

	sym->name		= 0;

	sym->status		= 0;

	if (!(exp_hdr = pe_get_image_export_hdr_addr(base,&sec_size)))

		return -1;

	sec_addr_cap = pe_va_from_rva(exp_hdr,sec_size);

	rva_offset   = (uint32_t *)(exp_hdr->eh_export_addr_tbl_rva);

	fn_addr      = (uint32_t *)pe_va_from_rva(base,*rva_offset);

	rva_offset   = (uint32_t *)(exp_hdr->eh_name_ptr_rva);

	fn_names     = (uint32_t *)pe_va_from_rva(base,*rva_offset);

	rva_offset   = (uint32_t *)(exp_hdr->eh_ordinal_tbl_rva);

	fn_ordinals  = (uint16_t *)pe_va_from_rva(base,*rva_offset);

	addr_entries = (uint32_t *)exp_hdr->eh_addr_tbl_entries;

	name_entries = (uint32_t *)exp_hdr->eh_num_of_name_ptrs;

	/* by ordinal? */

	if ((intptr_t)name < 0x10000) {

		sym->ordinal_base = (uint32_t *)exp_hdr->eh_ordinal_base;

		/* the array is zero-based, but ordinals are normally one-based... */

		if (((intptr_t)name - *sym->ordinal_base + 1) > *addr_entries)

			return -1;

		addr        = ((uintptr_t)name - *sym->ordinal_base) * sizeof(uint32_t);

		rva_offset  = (uint32_t *)pe_va_from_rva(fn_addr,addr);

		addr_offset = (uintptr_t *)pe_va_from_rva(base,*rva_offset);

		if (pe_addr_within_bounds(addr_offset,exp_hdr,sec_addr_cap)) {

			sym->forwarder_rva = addr_offset;

			sym->addr = pe_resolve_forwarder_rva((char *)addr_offset);

		} else {

			sym->forwarder_rva = 0;

			sym->addr = addr_offset;

		}

		return 0;

	}

	if ((len = pe_impl_strlen_ansi(name)) < 0)

		return -1;

	len++;

	lower  = 0;

	upper  = *name_entries;

	while (lower < upper) {

		idx        = (lower + upper) / 2;

		rva_offset = (uint32_t *)pe_va_from_rva(fn_names,idx*sizeof(uint32_t));

		exp_name   = (char *)pe_va_from_rva(base,*rva_offset);

		src = name;

		dst = exp_name;

		for (match=0; (match

				src++;

				dst++;

		}

		if (match == len) {

			sym->ordinal_base = (uint32_t *)exp_hdr->eh_ordinal_base;

			sym->ordinal      = (uint16_t *)pe_va_from_rva(fn_ordinals,idx*sizeof(uint16_t));

			rva_offset  = (uint32_t *)pe_va_from_rva(fn_addr,(*sym->ordinal)*sizeof(uint32_t));

			addr_offset = (uintptr_t *)pe_va_from_rva(base,*rva_offset);

			if (pe_addr_within_bounds(addr_offset,exp_hdr,sec_addr_cap)) {

				sym->forwarder_rva = addr_offset;

				sym->addr = pe_resolve_forwarder_rva((char *)addr_offset);

			} else {

				sym->forwarder_rva = 0;

				sym->addr = addr_offset;

			}

			return 0;

		}

		else {

			if (*src > *dst)

				lower = idx + 1;

			else

				upper = idx;

		}

	}

	return -1;

}