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

/*  perk: PE Resource Kit                                      */

/*  Copyright (C) 2015--2017  Z. Gilboa                        */

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

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

#include <stdint.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <perk/perk.h>

#include "perk_reader_impl.h"

#include "perk_errinfo_impl.h"

static int pe_free_image_meta_impl(struct pe_image_meta * meta, int ret)

{

	int i;

	if (meta) {

		for (i=0; i<meta->mstats.nimplibs; i++)

			free(meta->idata[i].ih_items);

		free(meta->idata);

		free(meta->sectbl);

		free(meta);

	}

	return ret;

}

void pe_free_image_meta(struct pe_image_meta * meta)

{

	pe_free_image_meta_impl(meta,0);

}

int pe_get_named_section_index(const struct pe_image_meta * m, const char * name)

{

	int i; for (i=0; i<m->coff.cfh_num_of_sections; i++)

		if (!(strcmp(name,m->sectbl[i].sh_name)))

			return i;

	return -1;

}

int pe_get_block_section_index(const struct pe_image_meta * m, const struct pe_block * block)

{

	int i;

	uint32_t low,high;

	if (m->aobj)

		return -1;

	for (i=0; i<m->coff.cfh_num_of_sections; i++) {

		low  = m->sectbl[i].sh_virtual_addr;

		high = low + m->sectbl[i].sh_virtual_size;

		if ((block->dh_rva >= low) && (block->dh_rva + block->dh_size <= high))

			return i;

	}

	return -1;

}

int pe_get_roffset_from_rva(const struct pe_image_meta * m, uint32_t rva, uint32_t * roffset)

{

	int i;

	uint32_t low,high;

	for (i=0; i<m->coff.cfh_num_of_sections; i++) {

		low  = m->sectbl[i].sh_virtual_addr;

		high = low + m->sectbl[i].sh_virtual_size;

		if ((rva >= low) && (rva < high)) {

			*roffset = (rva - low) + m->sectbl[i].sh_ptr_to_raw_data;

			return 0;

		}

	}

	return -1;

}

int pe_get_rva_from_roffset(const struct pe_image_meta * m, uint32_t roffset, uint32_t * rva)

{

	int i;

	uint32_t low,high,ref;

	for (i=0, ref=~0; i<m->coff.cfh_num_of_sections; i++) {

		low  = m->sectbl[i].sh_ptr_to_raw_data;

		high = low + m->sectbl[i].sh_virtual_size;

		if ((roffset >= low) && (roffset < high)) {

			*rva = (roffset - low) + m->sectbl[i].sh_virtual_addr;

			return 0;

		} else if (ref > low) {

			ref = low;

		}

	}

	if (roffset < ref) {

		*rva = roffset;

		return 0;

	}

	return -1;

}

int pe_get_expsym_by_name(

	const struct pe_image_meta *	m,

	const char *			name,

	struct pe_expsym *		expsym)

{

	uint32_t 	offset;

	uint32_t *	symrva;

	const char *	sym;

	unsigned	i;

	if (m->aobj || !m->hedata)

		return -1;

	offset	= m->hedata->sh_virtual_addr - m->hedata->sh_ptr_to_raw_data;

	symrva	= (uint32_t *)((uintptr_t)m->image.addr + (m->edata.eh_name_ptr_rva - offset));

	for (i=0; i<m->edata.eh_num_of_name_ptrs; i++) {

		sym = (const char *)m->image.addr + symrva[i] - offset;

		if (!(strcmp(sym,name))) {

			if (expsym) {

				expsym->name    = sym;

				expsym->eaddr   = 0;

				expsym->maddr   = 0;

				expsym->roffset = 0;

			}

			return 0;

		}

	}

	return -1;

}

int pe_get_expsym_by_index(

	const struct pe_image_meta *	m,

	unsigned			index,

	struct pe_expsym *		expsym)

{

	uint32_t 	offset;

	uint32_t *	symrva;

	uintptr_t	symaddr;

	if (m->aobj)

		return -1;

	if (index >= m->edata.eh_num_of_name_ptrs)

		return -1;

	if (expsym) {

		offset  = m->hedata->sh_virtual_addr - m->hedata->sh_ptr_to_raw_data;

		symrva  = (uint32_t *)((uintptr_t)m->image.addr + (m->edata.eh_name_ptr_rva - offset));

		symaddr = (uintptr_t)m->image.addr + symrva[index] - offset;

		expsym->name    = (const char *)symaddr;

		expsym->eaddr   = 0;

		expsym->maddr   = 0;

		expsym->roffset = 0;

	}

	return 0;

}

int pe_get_image_meta(

	const struct pe_driver_ctx *	dctx,

	const struct pe_raw_image *	image,

	struct pe_image_meta ** meta)

{

	int			ret;

	int 			i,s;

	long			l;

	unsigned		j;

	const unsigned char *	mark;

	struct pe_image_meta *	m;

	char *			base;

	base = image->addr;

	if (!(m = calloc(1,sizeof(*m))))

		return PERK_SYSTEM_ERROR(dctx);

	m->aobj = (struct pe_raw_coff_object_hdr *)base;

	if (pe_read_object_header(m->aobj,&m->coff)) {

		m->aobj = 0;

		m->ados = (struct pe_raw_image_dos_hdr *)base;

		if ((ret = (pe_read_dos_header(m->ados,&m->dos))))

			return pe_free_image_meta_impl(

				m,PERK_CUSTOM_ERROR(dctx,ret));

		m->acoff = (struct pe_raw_coff_image_hdr *)(base + m->dos.dos_lfanew);

		if ((ret = (pe_read_coff_header(m->acoff,&m->coff))))

			return pe_free_image_meta_impl(

				m,PERK_CUSTOM_ERROR(dctx,ret));

	}

	mark  = (const unsigned char *)base + m->coff.cfh_ptr_to_sym_tbl;

	mark += m->coff.cfh_num_of_syms * sizeof(struct pe_raw_coff_symbol);

	if (m->coff.cfh_ptr_to_sym_tbl) {

		m->coff.cfh_ptr_to_str_tbl  = m->coff.cfh_ptr_to_sym_tbl;

		m->coff.cfh_ptr_to_str_tbl += m->coff.cfh_num_of_syms * sizeof(struct pe_raw_coff_symbol);

		m->coff.cfh_size_of_str_tbl = pe_read_long(mark);

	}

	if (m->ados) {

		mark    = &m->acoff->cfh_signature[0];

		m->aopt = (union pe_raw_opt_hdr *)(mark + sizeof(*m->acoff));

		if ((ret = (pe_read_optional_header(m->aopt,&m->opt))))

			return pe_free_image_meta_impl(

				m,PERK_CUSTOM_ERROR(dctx,ret));

		mark       = &m->aopt->opt_hdr_32.coh_magic[0];

		m->asectbl = (struct pe_raw_sec_hdr *)(mark + m->coff.cfh_size_of_opt_hdr);

	} else {

		mark       = &m->aobj->cfh_machine[0];

		m->asectbl = (struct pe_raw_sec_hdr *)(mark + sizeof(*m->aobj));

	}

	if (!(m->sectbl = calloc(m->coff.cfh_num_of_sections,sizeof(*(m->sectbl)))))

		return pe_free_image_meta_impl(

			m,PERK_SYSTEM_ERROR(dctx));

	for (i=0; i<m->coff.cfh_num_of_sections; i++) {

		pe_read_section_header(&m->asectbl[i],&m->sectbl[i]);

		if (m->sectbl[i].sh_name[0] == '/')

			if ((l = strtol(&m->sectbl[i].sh_name[1],0,10)) > 0)

				if (l < m->coff.cfh_size_of_str_tbl)

					m->sectbl[i].sh_long_name = base + m->coff.cfh_ptr_to_str_tbl + l;

	}

	/* .edata */

	i = pe_get_named_section_index(m,".edata");

	s = pe_get_block_section_index(m,&m->opt.oh_dirs.coh_export_tbl);

	if ((i >= 0) && (i != s))

		return pe_free_image_meta_impl(

			m,PERK_CUSTOM_ERROR(dctx,PERK_ERR_IMAGE_MALFORMED));

	if (s >= 0) {

		m->hedata = &m->sectbl[s];

		m->aedata = (struct pe_raw_export_hdr *)(base + m->sectbl[s].sh_ptr_to_raw_data

				+ m->opt.oh_dirs.coh_export_tbl.dh_rva - m->sectbl[s].sh_virtual_addr);

	} else if (i >= 0) {

		m->hedata = &m->sectbl[i];

		m->aedata = (struct pe_raw_export_hdr *)(base + m->sectbl[i].sh_ptr_to_raw_data);

	}

	if (m->aedata) {

		pe_read_export_header(m->aedata,&m->edata);

		m->mstats.nexpsyms = m->edata.eh_num_of_name_ptrs;

	}

	/* .idata */

	struct pe_raw_import_hdr * 	pidata;

	union  pe_raw_import_lookup *	pitem;

	i = pe_get_named_section_index(m,".idata");

	s = pe_get_block_section_index(m,&m->opt.oh_dirs.coh_import_tbl);

	if ((i >= 0) && (i != s))

		return pe_free_image_meta_impl(

			m,PERK_CUSTOM_ERROR(dctx,PERK_ERR_IMAGE_MALFORMED));

	if (s >= 0) {

		m->hidata = &m->sectbl[s];

		m->aidata = (struct pe_raw_import_hdr *)(base + m->sectbl[s].sh_ptr_to_raw_data

				+ m->opt.oh_dirs.coh_import_tbl.dh_rva - m->sectbl[s].sh_virtual_addr);

	} else if (i >= 0) {

		m->hidata = &m->sectbl[i];

		m->aidata = (struct pe_raw_import_hdr *)(base + m->sectbl[i].sh_ptr_to_raw_data);

	}

	if (m->aidata) {

		/* num of implibs */

		for (pidata=m->aidata; pe_read_long(pidata->ih_name_rva); pidata++)

			m->mstats.nimplibs++;

		/* import headers */

		if (!(m->idata = calloc(m->mstats.nimplibs,sizeof(*m->idata))))

			return pe_free_image_meta_impl(

				m,PERK_SYSTEM_ERROR(dctx));

		for (i=0; i<m->mstats.nimplibs; i++) {

			pe_read_import_header(&m->aidata[i],&m->idata[i]);

			m->idata[i].ih_name = base + m->hidata->sh_ptr_to_raw_data

						   + m->idata[i].ih_name_rva

						   - m->hidata->sh_virtual_addr;

			if (m->idata[i].ih_import_lookup_tbl_rva)

				m->idata[i].ih_aitems = (union pe_raw_import_lookup *)(base + m->hidata->sh_ptr_to_raw_data

							+ m->idata[i].ih_import_lookup_tbl_rva

							- m->hidata->sh_virtual_addr);

			/* items */

			uint32_t * hint;

			m->idata[i].ih_count = 0;

			if (m->idata[i].ih_import_lookup_tbl_rva) {

				pitem = m->idata[i].ih_aitems;

				hint  = (uint32_t *)pitem->ii_hint_name_tbl_rva;

				for (; *hint; hint=(uint32_t *)((++pitem)->ii_hint_name_tbl_rva))

					m->idata[i].ih_count++;

				if (!(m->idata[i].ih_items = calloc(m->idata[i].ih_count,sizeof(*(m->idata[i].ih_items)))))

					return pe_free_image_meta_impl(

						m,PERK_SYSTEM_ERROR(dctx));

			}

			for (j=0; j<m->idata[i].ih_count; j++) {

				if ((ret = pe_read_import_lookup(

						&(m->idata[i].ih_aitems[j]),

						&(m->idata[i].ih_items[j]),

						m->opt.oh_std.coh_magic)))

					return pe_free_image_meta_impl(

						m,PERK_CUSTOM_ERROR(dctx,ret));

				switch (m->opt.oh_std.coh_magic) {

					case PE_MAGIC_PE32:

						m->idata[i].ih_items[j].ii_flags = m->idata[i].ih_items[j].u.ii_import_lookup_entry_32;

						break;

					case PE_MAGIC_PE32_PLUS:

						m->idata[i].ih_items[j].ii_flags = (m->idata[i].ih_items[j].u.ii_import_lookup_entry_64 >> 32);

						break;

				}

				if (!m->idata[i].ih_items[j].ii_flags) {

					struct pe_raw_hint_name_entry * pentry =

						(struct pe_raw_hint_name_entry *)(base + m->hidata->sh_ptr_to_raw_data

							+ m->idata[i].ih_items[j].u.ii_hint_name_tbl_rva - m->hidata->sh_virtual_addr);

					m->idata[i].ih_items[j].ii_name = (char *)pentry->ii_name;

				}

			}

		}

	}

	/* image */

	m->image.addr = image->addr;

	m->image.size = image->size;

	/* all done */

	*meta = m;

	return 0;

}