Blame src/exports/pe_get_export_symbol_info.c

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/*****************************************************************************/
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/*  pemagination: a (virtual) tour into portable bits and executable bytes   */
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/*  Copyright (C) 2013--2017  Z. Gilboa                                      */
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/*  Released under GPLv2 and GPLv3; see COPYING.PEMAGINE.                    */
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/*****************************************************************************/
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#include <psxtypes/psxtypes.h>
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#include <pemagine/pe_consts.h>
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#include <pemagine/pe_structs.h>
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#include <pemagine/pemagine.h>
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#include "pe_impl.h"
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static __inline__ int pe_addr_within_bounds(void * addr, void * bottom, void * top)
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{
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	return (((uintptr_t)addr >= (uintptr_t)bottom) && ((uintptr_t)addr < (uintptr_t)top));
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}
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static void * pe_resolve_forwarder_rva(char * forwarder)
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{
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	uint16_t	soname[512];
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	uint16_t *	wch;
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	char *		mark;
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	char *		dot;
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	void *		base;
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	for (mark=forwarder; *mark; mark++)
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		(void)0;
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	if (mark - forwarder + 5 > 512)
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		return 0;
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	for (dot=&mark[-1]; dot>forwarder && *dot!='.'; dot--)
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		(void)0;
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	if (*dot != '.')
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		return 0;
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	mark = forwarder;
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	wch  = soname;
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	for (; mark
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		*wch++ = *mark++;
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	if (mark < dot)
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		return 0;
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	*wch++ = '.';
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	*wch++ = 'd';
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	*wch++ = 'l';
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	*wch++ = 'l';
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	*wch++ = 0;
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	if (!(base = pe_get_module_handle(soname)))
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		return 0;
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	return pe_get_procedure_address(base,++dot);
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}
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int pe_get_export_symbol_info(
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	const void *		base,
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	const char *		name,
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	struct pe_export_sym *	sym)
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{
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	struct pe_raw_export_hdr * exp_hdr;
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	ssize_t		len;
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	uint32_t *	rva_offset;
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	uintptr_t *	addr_offset;
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	uintptr_t	addr;
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	uint32_t	sec_size;
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	void *		sec_addr_cap;
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	uint32_t *	fn_addr;
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	uint32_t *	fn_names;
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	uint16_t *	fn_ordinals;
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	uint32_t *	addr_entries;
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	uint32_t *	name_entries;
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	char *		exp_name;
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	const char *	src;
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	const char *	dst;
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	ssize_t		match;
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	uint32_t	lower;
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	uint32_t	upper;
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	uint32_t	idx;
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	/* init */
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	sym->ordinal_base	= 0;
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	sym->ordinal		= 0;
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	sym->addr		= 0;
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	sym->forwarder_rva	= 0;
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	sym->name		= 0;
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	sym->status		= 0;
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	if (!(exp_hdr = pe_get_image_export_hdr_addr(base,&sec_size)))
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		return -1;
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	sec_addr_cap = pe_va_from_rva(exp_hdr,sec_size);
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	rva_offset   = (uint32_t *)(exp_hdr->eh_export_addr_tbl_rva);
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	fn_addr      = (uint32_t *)pe_va_from_rva(base,*rva_offset);
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	rva_offset   = (uint32_t *)(exp_hdr->eh_name_ptr_rva);
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	fn_names     = (uint32_t *)pe_va_from_rva(base,*rva_offset);
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	rva_offset   = (uint32_t *)(exp_hdr->eh_ordinal_tbl_rva);
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	fn_ordinals  = (uint16_t *)pe_va_from_rva(base,*rva_offset);
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	addr_entries = (uint32_t *)exp_hdr->eh_addr_tbl_entries;
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	name_entries = (uint32_t *)exp_hdr->eh_num_of_name_ptrs;
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	/* by ordinal? */
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	if ((intptr_t)name < 0x10000) {
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		sym->ordinal_base = (uint32_t *)exp_hdr->eh_ordinal_base;
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		/* the array is zero-based, but ordinals are normally one-based... */
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		if (((intptr_t)name - *sym->ordinal_base + 1) > *addr_entries)
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			return -1;
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		addr        = ((uintptr_t)name - *sym->ordinal_base) * sizeof(uint32_t);
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		rva_offset  = (uint32_t *)pe_va_from_rva(fn_addr,addr);
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		addr_offset = (uintptr_t *)pe_va_from_rva(base,*rva_offset);
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		if (pe_addr_within_bounds(addr_offset,exp_hdr,sec_addr_cap)) {
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			sym->forwarder_rva = addr_offset;
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			sym->addr = pe_resolve_forwarder_rva((char *)addr_offset);
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		} else {
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			sym->forwarder_rva = 0;
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			sym->addr = addr_offset;
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		}
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		return 0;
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	}
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	if ((len = pe_impl_strlen_ansi(name)) < 0)
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		return -1;
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	len++;
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	lower  = 0;
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	upper  = *name_entries;
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	while (lower < upper) {
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		idx        = (lower + upper) / 2;
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		rva_offset = (uint32_t *)pe_va_from_rva(fn_names,idx*sizeof(uint32_t));
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		exp_name   = (char *)pe_va_from_rva(base,*rva_offset);
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		src = name;
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		dst = exp_name;
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		for (match=0; (match
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				src++;
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				dst++;
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		}
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		if (match == len) {
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			sym->ordinal_base = (uint32_t *)exp_hdr->eh_ordinal_base;
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			sym->ordinal      = (uint16_t *)pe_va_from_rva(fn_ordinals,idx*sizeof(uint16_t));
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			rva_offset  = (uint32_t *)pe_va_from_rva(fn_addr,(*sym->ordinal)*sizeof(uint32_t));
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			addr_offset = (uintptr_t *)pe_va_from_rva(base,*rva_offset);
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			if (pe_addr_within_bounds(addr_offset,exp_hdr,sec_addr_cap)) {
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				sym->forwarder_rva = addr_offset;
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				sym->addr = pe_resolve_forwarder_rva((char *)addr_offset);
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			} else {
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				sym->forwarder_rva = 0;
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				sym->addr = addr_offset;
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			}
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			return 0;
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		}
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		else {
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			if (*src > *dst)
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				lower = idx + 1;
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			else
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				upper = idx;
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		}
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	}
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	return -1;
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}