/*****************************************************************************/
/*  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/pemagine.h>


struct pe_symbol_name_ctx {
	const void *	addr;
	char *		name;
};

static int pe_enum_exports_callback(
	const void *			base,
	struct pe_raw_export_hdr *	exp_hdr,
	struct pe_export_sym *		sym,
	enum pe_callback_reason		reason,
	void *				context);

#if (__SIZEOF_POINTER__ == 4)
static char * pe_get_imported_symbol_info_32(
	const void *			sym_addr,
	struct pe_ldr_tbl_entry **	ldr_tbl_entry);
#endif

#if (__SIZEOF_POINTER__ == 8)
static char * pe_get_imported_symbol_info_64(
	const void *			sym_addr,
	struct pe_ldr_tbl_entry **	ldr_tbl_entry);
#endif


char * pe_get_symbol_name(const void * base, const void * sym_addr)
{
	struct pe_export_sym		exp_item;
	struct pe_symbol_name_ctx	ctx;

	ctx.name = 0;
	ctx.addr = sym_addr;

	pe_enum_image_exports(
		base,
		pe_enum_exports_callback,
		&exp_item,
		&ctx);

	return ctx.name;
}


char * pe_get_import_symbol_info(
	const void *			sym_addr,
	struct pe_ldr_tbl_entry **	ldr_tbl_entry)
{
	#if (__SIZEOF_POINTER__ == 4)
		return pe_get_imported_symbol_info_32(
			sym_addr,
			ldr_tbl_entry);
	#elif (__SIZEOF_POINTER__ == 8)
		return pe_get_imported_symbol_info_64(
			sym_addr,
			ldr_tbl_entry);
	#endif
}

static int pe_enum_exports_callback(
	const void *			base,
	struct pe_raw_export_hdr *	exp_hdr,
	struct pe_export_sym  *		sym,
	enum pe_callback_reason		reason,
	void *				context)
{
	struct pe_symbol_name_ctx * ctx;

	(void)base;
	(void)exp_hdr;

	if (reason != PE_CALLBACK_REASON_ITEM)
		return 1;

	ctx = (struct pe_symbol_name_ctx *)context;

	if (sym->addr == ctx->addr) {
		ctx->name = sym->name;
		return 0;
	} else
		return 1;
}


#if (__SIZEOF_POINTER__ == 4)
static char * pe_get_imported_symbol_info_32(
	const void *			sym_addr,
	struct pe_ldr_tbl_entry **	ldr_tbl_entry)
{
	struct symbol {
		unsigned char	call;
		unsigned char	ds;
		unsigned char	sym_addr[4];
		unsigned char	padding[2];
	};

	char *				fn_name;
	struct pe_ldr_tbl_entry *	mod_info;
	void *				mod_base;
	uint32_t ***			sym_redirected_addr;
	struct symbol *			sym;

	fn_name  = 0;
	sym = (struct symbol *)sym_addr;

	if ((sym->call == 0xff) && (sym->ds == 0x25))
		if ((sym_redirected_addr = (uint32_t ***)sym->sym_addr))
			if ((mod_info = pe_get_symbol_module_info(
					**sym_redirected_addr)))
				if ((mod_base = mod_info->dll_base))
					fn_name = pe_get_symbol_name(
						mod_base,
						**sym_redirected_addr);
	if (fn_name && ldr_tbl_entry)
		*ldr_tbl_entry = mod_info;

	return fn_name;
}
#endif


#if (__SIZEOF_POINTER__ == 8)
static char * pe_get_imported_symbol_info_64(
	const void *			sym_addr,
	struct pe_ldr_tbl_entry **	ldr_tbl_entry)
{
	struct symbol {
		unsigned char	call;
		unsigned char	ds;
		unsigned char	sym_addr[4];
		unsigned char	padding[2];
	};

	char *				fn_name;
	struct pe_ldr_tbl_entry *	mod_info;
	void *				mod_base;
	uint32_t *			sym_offset;
	uint32_t			offset;
	struct symbol *			sym;

	fn_name  = 0;
	mod_info = 0;
	sym = (struct symbol *)sym_addr;

	if ((sym->call == 0xff) && (sym->ds == 0x25)) {
		if ((sym_offset = (uint32_t *)sym->sym_addr)) {
			offset   = *sym_offset;
			sym_addr = *(void **)(offset + (uintptr_t)(++sym_offset));
		} else
			sym_addr = 0;

		if (sym_addr && (mod_info = pe_get_symbol_module_info(sym_addr)))
			if ((mod_base = mod_info->dll_base))
				fn_name = pe_get_symbol_name(
					mod_base,
					sym_addr);
	}

	if (fn_name && ldr_tbl_entry)
		*ldr_tbl_entry = mod_info;

	return fn_name;
}
#endif