/********************************************************/
/*  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_impl.h"

int32_t __stdcall __ntapi_tt_open_physical_parent_directory(
	__out	void **		hparent,
	__in	void *		hdir,
	__out	uintptr_t *	buffer,
	__in	uint32_t	buffer_size,
	__in	uint32_t	desired_access,
	__in	uint32_t	open_options)
{
	int32_t				status;
	nt_oa				oa;
	nt_iosb				iosb;
	wchar16_t *			wch;
	wchar16_t *			root;
	nt_unicode_string *		path;
	uint32_t			len;

	path = (nt_unicode_string *)buffer;

	if ((status = __ntapi->zw_query_object(
			hdir,
			NT_OBJECT_NAME_INFORMATION,
			path,
			buffer_size,
			&len)))
		return status;

	/* integrity */
	if (len == sizeof(nt_unicode_string))
		return NT_STATUS_BAD_FILE_TYPE;

	/* device root directory */
	root = path->buffer;
	wch  = path->buffer + (path->strlen / sizeof(uint16_t));


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

	for (root=&root[8]; (root<wch) && (*root!='\\'); )
		root++;

	if ((uint16_t)((++root - path->buffer) * sizeof(uint16_t)) == path->strlen)
		return NT_STATUS_MORE_PROCESSING_REQUIRED;

	/* physical parent directory path */
	for (; (wch>root) && (wch[-1]!='\\'); )
		wch--;

	path->strlen = sizeof(uint16_t) * (uint16_t)(wch-path->buffer);
	path->maxlen = 0;

	/* oa */
	oa.len = sizeof(nt_oa);
	oa.root_dir = 0;
	oa.obj_name = path;
	oa.obj_attr = 0;
	oa.sec_desc = 0;
	oa.sec_qos  = 0;

	/* default access */
	desired_access = desired_access
		? desired_access
		: NT_SEC_SYNCHRONIZE | NT_FILE_READ_ATTRIBUTES | NT_FILE_READ_ACCESS;

	/* open parent directory */
	return __ntapi->zw_open_file(
		hparent,
		desired_access,
		&oa,
		&iosb,
		NT_FILE_SHARE_READ | NT_FILE_SHARE_WRITE,
		open_options | NT_FILE_DIRECTORY_FILE);
}