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

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

/*  Copyright (C) 2013--2017  Z. Gilboa                                      */

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

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

#include <psxtypes/psxtypes.h>

#include <pemagine/pemagine.h>

#include "pe_os.h"

struct pe_framework_cmdline {

	struct pe_guid_str_utf16	guid;

	wchar16_t			space1;

	wchar16_t			rarg[2];

	wchar16_t			space2;

	wchar16_t			addr[2*__SIZEOF_POINTER__];

	wchar16_t			null;

};

static int32_t pe_hex_utf16_to_uint32(

	const wchar16_t	hex_key_utf16[8],

	uint32_t *	key)

{

	int		i;

	unsigned char	uch[8];

	unsigned char	ubytes[4];

	uint32_t *	key_ret;

	/* input validation */

	for (i=0; i<8; i++)

		if (!((hex_key_utf16[i] >= 'a') && (hex_key_utf16[i] <= 'f')))

			if (!((hex_key_utf16[i] >= 'A') && (hex_key_utf16[i] <= 'F')))

				if (!((hex_key_utf16[i] >= '0') && (hex_key_utf16[i] <= '9')))

					return OS_STATUS_ILLEGAL_CHARACTER;

	/* intermediate step: little endian byte order */

	uch[0] = (unsigned char)hex_key_utf16[6];

	uch[1] = (unsigned char)hex_key_utf16[7];

	uch[2] = (unsigned char)hex_key_utf16[4];

	uch[3] = (unsigned char)hex_key_utf16[5];

	uch[4] = (unsigned char)hex_key_utf16[2];

	uch[5] = (unsigned char)hex_key_utf16[3];

	uch[6] = (unsigned char)hex_key_utf16[0];

	uch[7] = (unsigned char)hex_key_utf16[1];

	for (i=0; i<8; i++) {

		/* 'a' > 'A' > '0' */

		if (uch[i] >= 'a')

			uch[i] -= ('a' - 0x0a);

		else if (uch[i] >= 'A')

			uch[i] -= ('A' - 0x0a);

		else

			uch[i] -= '0';

	}

	ubytes[0] = uch[0] * 0x10 + uch[1];

	ubytes[1] = uch[2] * 0x10 + uch[3];

	ubytes[2] = uch[4] * 0x10 + uch[5];

	ubytes[3] = uch[6] * 0x10 + uch[7];

	key_ret = (uint32_t *)ubytes;

	*key = *key_ret;

	return OS_STATUS_SUCCESS;

}

static int32_t pe_hex_utf16_to_uint16(

	const wchar16_t hex_key_utf16[4],

	uint16_t *	key)

{

	int32_t		status;

	uint32_t	dword_key;

	wchar16_t	hex_buf[8] = {'0','0','0','0'};

	hex_buf[4] = hex_key_utf16[0];

	hex_buf[5] = hex_key_utf16[1];

	hex_buf[6] = hex_key_utf16[2];

	hex_buf[7] = hex_key_utf16[3];

	if ((status = pe_hex_utf16_to_uint32(hex_buf,&dword_key)))

		return status;

	*key = (uint16_t)dword_key;

	return OS_STATUS_SUCCESS;

}

static int32_t pe_hex_utf16_to_uint64(

	const wchar16_t	hex_key_utf16[16],

	uint64_t *	key)

{

	int32_t		status;

	uint32_t	x64_key[2];

	uint64_t *	key_ret;

	if ((status = pe_hex_utf16_to_uint32(

			&hex_key_utf16[0],

			&x64_key[1])))

		return status;

	if ((status = pe_hex_utf16_to_uint32(

			&hex_key_utf16[8],

			&x64_key[0])))

		return status;

	key_ret = (uint64_t *)x64_key;

	*key    = *key_ret;

	return OS_STATUS_SUCCESS;

}

static int32_t pe_hex_utf16_to_uintptr(

	const wchar16_t	hex_key_utf16[],

	uintptr_t *	key)

{

	#if (__SIZEOF_POINTER__ == 4)

		return pe_hex_utf16_to_uint32(hex_key_utf16,key);

	#elif (__SIZEOF_POINTER__ == 8)

		return pe_hex_utf16_to_uint64(hex_key_utf16,key);

	#endif

}

static int32_t pe_string_to_guid_utf16(

	const struct pe_guid_str_utf16 *guid_str,

	struct pe_guid *		guid)

{

	int32_t			status;

	uint16_t		key;

	const wchar16_t *	wch;

	if ((guid_str->lbrace != '{')

			|| (guid_str->rbrace != '}')

			|| (guid_str->dash1 != '-')

			|| (guid_str->dash2 != '-')

			|| (guid_str->dash3 != '-')

			|| (guid_str->dash4 != '-'))

		return OS_STATUS_INVALID_PARAMETER;

	wch = &(guid_str->group5[0]);

	if ((status = pe_hex_utf16_to_uint32(

			guid_str->group1,

			&guid->data1)))

		return status;

	if ((status = pe_hex_utf16_to_uint16(

			guid_str->group2,

			&guid->data2)))

		return status;

	if ((status = pe_hex_utf16_to_uint16(

			guid_str->group3,

			&guid->data3)))

		return status;

	if ((status = pe_hex_utf16_to_uint16(

			guid_str->group4,

			&key)))

		return status;

	guid->data4[0] = key >> 8;

	guid->data4[1] = key % 0x100;

	if ((status = pe_hex_utf16_to_uint16(

			&(wch[0]),

			&key)))

		return status;

	guid->data4[2] = key >> 8;

	guid->data4[3] = key % 0x100;

	if ((status = pe_hex_utf16_to_uint16(

			&(wch[4]),

			&key)))

		return status;

	guid->data4[4] = key >> 8;

	guid->data4[5] = key % 0x100;

	if ((status = pe_hex_utf16_to_uint16(

			&(wch[8]),

			&key)))

		return status;

	guid->data4[6] = key >> 8;

	guid->data4[7] = key % 0x100;

	return OS_STATUS_SUCCESS;

}

static int32_t pe_guid_compare(

	const struct pe_guid *	pguid_dst,

	const struct pe_guid *	pguid_src)

{

	const uint32_t *	dst;

	const uint32_t *	src;

	dst = &pguid_dst->data1;

	src = &pguid_src->data1;

	if ((dst[0] == src[0])

			&& (dst[1] == src[1])

			&& (dst[2] == src[2])

			&& (dst[3] == src[3]))

		return OS_STATUS_SUCCESS;

	return OS_STATUS_NO_MATCH;

}

int32_t pe_get_framework_runtime_data(

	struct pe_framework_runtime_data **	rtdata,

	const wchar16_t *			cmdline,

	const struct pe_guid *			abi)

{

	int32_t					status;

	struct pe_framework_runtime_data *	prtdata;

	struct pe_framework_cmdline *		fcmdline;

	struct pe_guid				guid;

	uintptr_t				address;

	uintptr_t				buffer;

	void *					hntdll;

	os_zw_read_virtual_memory *		zw_read_virtual_memory;

	/* init */

	if (!(hntdll = pe_get_ntdll_module_handle()))

		return OS_STATUS_INTERNAL_ERROR;

	if (!(zw_read_virtual_memory = (os_zw_read_virtual_memory *)pe_get_procedure_address(

			hntdll,"ZwReadVirtualMemory")))

		return OS_STATUS_INTERNAL_ERROR;

	/* framework cmdline */

	fcmdline = (struct pe_framework_cmdline *)cmdline;

	/* framework cmdline: conformance */

	if (fcmdline->null)

		return OS_STATUS_INVALID_PARAMETER;

	/* framework cmdline: rarg */

	if ((fcmdline->space1 != ' ')

			|| (fcmdline->space2  != ' ')

			|| (fcmdline->rarg[0] != '-')

			|| (fcmdline->rarg[1] != 'r'))

		return OS_STATUS_INVALID_PARAMETER;

	/* framework cmdline: address */

	if ((status = pe_hex_utf16_to_uintptr(

			fcmdline->addr,

			&address)))

		return status;

	/* framework cmdline: guid */

	if ((status = pe_string_to_guid_utf16(

			&fcmdline->guid,

			&guid)))

		return status;

	/* framework cmdline: abi */

	if ((status = pe_guid_compare(&guid,abi)))

		return status;

	/* address: alignment */

	if (address & 0xFFF)

		return OS_STATUS_INVALID_ADDRESS;

	/* address is aligned at page boundary */

	if ((status = zw_read_virtual_memory(

			OS_CURRENT_PROCESS_HANDLE,

			(void *)address,

			(char *)&buffer,

			sizeof(buffer),

			0)))

		return status;

	/* rtdata */

	prtdata = (struct pe_framework_runtime_data *)address;

	/* rtdata: abi */

	if (pe_guid_compare(&prtdata->abi,abi))

		return OS_STATUS_CONTEXT_MISMATCH;

	/* yay */

	*rtdata = prtdata;

	return OS_STATUS_SUCCESS;

}