/********************************************************/
/*  ntapi: Native API core library                      */
/*  Copyright (C) 2013--2016  Z. Gilboa                 */
/*  Released under GPLv2 and GPLv3; see COPYING.NTAPI.  */
/********************************************************/

#include <ntapi/ntapi.h>
#include <ntapi/nt_file.h>
#include <ntapi/nt_fsctl.h>
#include <ntapi/nt_mount.h>
#include <ntapi/nt_istat.h>
#include "ntapi_impl.h"

int32_t __stdcall __ntapi_tt_istat(
	__in	void *			hfile,
	__in	void *			hroot	__optional,
	__in	nt_unicode_string *	path,
	__out	nt_istat *		istat,
	__out	uintptr_t *		buffer,
	__in	uint32_t		buffer_size,
	__in	uint32_t		open_options,
	__in	uint32_t		flags)
{
	int32_t			status;

	nt_oa			oa;
	nt_iosb			iosb;
	nt_unicode_string *	sdev;
	wchar16_t *		wch;
	wchar16_t *		wch_mark;

	/* validaton */
	if (!hfile && !path)
		return NT_STATUS_INVALID_HANDLE;

	/* hfile */
	if (!hfile) {
		/* oa */
		oa.len = sizeof(nt_oa);
		oa.root_dir = hroot;
		oa.obj_name = path;
		oa.obj_attr = 0;
		oa.sec_desc = 0;
		oa.sec_qos = 0;

		/* open file/folder */
		if ((status = __ntapi->zw_open_file(
				&hfile,
				NT_SEC_SYNCHRONIZE
					| NT_FILE_READ_ATTRIBUTES
					| NT_FILE_READ_ACCESS,
				&oa,
				&iosb,
				NT_FILE_SHARE_READ | NT_FILE_SHARE_WRITE,
				open_options | NT_FILE_SYNCHRONOUS_IO_ALERT)))
			return status;

		istat->flags_out = NT_STAT_NEW_HANDLE;
	}

	istat->hfile    = hfile;
	istat->flags_in = flags;

	/* file index number */
	if ((status = __ntapi->zw_query_information_file(
			hfile,
			&iosb,
			&istat->fii,
			sizeof(istat->fii),
			NT_FILE_INTERNAL_INFORMATION)))
		return status;

	/* attributes & reparse tag information */
	if ((status = __ntapi->zw_query_information_file(
			hfile,
			&iosb,
			&istat->ftagi,
			sizeof(istat->ftagi),
			NT_FILE_ATTRIBUTE_TAG_INFORMATION)))
		return status;

	/* system-unique device name */
	if ((status = __ntapi->zw_query_object(
			hfile,
			NT_OBJECT_NAME_INFORMATION,
			buffer,
			buffer_size,
			(uint32_t *)&iosb.info)))
		return status;

	sdev = (nt_unicode_string *)buffer;
	wch  = sdev->buffer;

	if (sdev->strlen < __DEVICE_PATH_PREFIX_LEN)
		return NT_STATUS_INVALID_HANDLE;

	if ((wch[0] != '\\')
			|| (wch[1] != 'D')
			|| (wch[2] != 'e')
			|| (wch[3] != 'v')
			|| (wch[4] != 'i')
			|| (wch[5] != 'c')
			|| (wch[6] != 'e')
			|| (wch[7] != '\\'))
		return NT_STATUS_INVALID_HANDLE;

	wch_mark = &wch[8];
	wch      = wch_mark;

	while (*wch != '\\')
		wch++;

	istat->dev_name_strlen = (uint16_t)((wch - sdev->buffer) * sizeof(uint16_t));
	istat->dev_name_hash   = __ntapi->tt_buffer_crc32(
		__DEVICE_PATH_PREFIX_HASH,
		wch_mark,
		(uintptr_t)wch - (uintptr_t)wch_mark);

	return status;
}


int32_t __stdcall __ntapi_tt_validate_fs_handle(
	__in	void *		hfile,
	__in	uint32_t	dev_name_hash,
	__in	nt_fii		fii,
	__out	uintptr_t *	buffer,
	__in	uint32_t	buffer_size)
{
	int32_t		status;
	nt_istat	istat;

	status = __ntapi->tt_istat(
		hfile,
		(void *)0,
		(nt_unicode_string *)0,
		&istat,
		buffer,
		buffer_size,
		0,
		NT_ISTAT_DEFAULT);

	if (status) return status;

	if (istat.fii.index_number.quad != fii.index_number.quad)
		return NT_STATUS_CONTEXT_MISMATCH;
	else if (istat.dev_name_hash != dev_name_hash)
		return NT_STATUS_CONTEXT_MISMATCH;

	return NT_STATUS_SUCCESS;
}