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

/*  perk: PE Resource Kit                                      */

/*  Copyright (C) 2015--2016  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"

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

{

	unsigned i;

	if (meta) {

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

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

		free(meta->idata);

		free(meta->sectbl);

		free(meta);

	}

	return status;

}

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.num_of_sections; i++)

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

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

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

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

		if ((block->rva >= low) && (block->rva + block->size <= high))

			return i;

	}

	return -1;

}

int pe_get_image_meta(const struct pe_raw_image * image, struct pe_image_meta ** meta)

{

	int i,j,s,status;

	struct pe_image_meta * m;

	char * base = image->addr;

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

		return -1;

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

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

		return pe_free_image_meta_impl(m,status);

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

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

		return pe_free_image_meta_impl(m,status);

	m->aopt = (union pe_opt_hdr *)((char *)m->acoff + sizeof(m->coff));

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

		return pe_free_image_meta_impl(m,status);

	m->asectbl = (struct pe_sec_hdr *)((char *)m->aopt  + m->coff.size_of_opt_hdr);

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

		return pe_free_image_meta_impl(m,status);

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

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

	/* .edata */

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

	s = pe_get_block_section_index(m,&m->opt.dirs.export_tbl);

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

		return pe_free_image_meta_impl(m,PERK_MALFORMED_IMAGE);

	if (s >= 0) {

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

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

				+ m->opt.dirs.export_tbl.rva - m->sectbl[s].virtual_addr);

	} else if (i >= 0) {

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

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

	}

	if (m->aedata)

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

	/* .idata */

	struct pe_import_hdr * 		pidata;

	union  pe_import_lookup_item *	pitem;

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

	s = pe_get_block_section_index(m,&m->opt.dirs.import_tbl);

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

		return pe_free_image_meta_impl(m,PERK_MALFORMED_IMAGE);

	if (s >= 0) {

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

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

				+ m->opt.dirs.import_tbl.rva - m->sectbl[s].virtual_addr);

	} else if (i >= 0) {

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

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

	}

	if (m->aidata) {

		/* num of implibs */

		for (pidata=m->aidata; pidata->name_rva[0]; pidata++,m->summary.nimplibs++);

		/* import headers */

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

			return pe_free_image_meta_impl(m,status);

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

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

			m->idata[i].name = base + m->hidata->ptr_to_raw_data

						+ m->idata[i].name_rva - m->hidata->virtual_addr;

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

				m->idata[i].aitems = (union pe_import_lookup_item *)(base + m->hidata->ptr_to_raw_data

							+ m->idata[i].import_lookup_tbl_rva - m->hidata->virtual_addr);

			/* items */

			uint32_t * hint;

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

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

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

				hint  = (uint32_t *)pitem->hint_name_tbl_rva;

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

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

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

					return pe_free_image_meta_impl(m,status);

			}

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

				if ((status = pe_read_import_lookup_item(

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

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

						m->opt.std.magic)))

					return pe_free_image_meta_impl(m,status);

				switch (m->opt.std.magic) {

					case PE_MAGIC_PE32:

						m->idata[i].items[j].flags = m->idata[i].items[j].u.import_lookup_entry_32;

						break;

					case PE_MAGIC_PE32_PLUS:

						m->idata[i].items[j].flags = (m->idata[i].items[j].u.import_lookup_entry_64 >> 32);

						break;

				}

				if (!m->idata[i].items[j].flags) {

					struct pe_hint_name_entry * pentry =

						(struct pe_hint_name_entry *)(base + m->hidata->ptr_to_raw_data

							+ m->idata[i].items[j].u.hint_name_tbl_rva - m->hidata->virtual_addr);

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

				}

			}

		}

	}

	/* image */

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

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

	/* all done */

	*meta = m;

	return 0;

}