/********************************************************/
/*  ntapi: Native API core library                      */
/*  Copyright (C) 2013--2021  SysDeer Technologies, LLC */
/*  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,
	__out	nt_istat *		istat,
	__in	uint32_t		infolen,
	__out	uintptr_t *		buffer,
	__in	uint32_t		buffer_size,
	__in	uint32_t		flags)
{
	int32_t			status;

	nt_iosb			iosb;
	nt_unicode_string *	sdev;
	wchar16_t *		wch;
	wchar16_t *		wch_mark;
	wchar16_t *		wch_cap;
	uint32_t		hash;
	uint32_t		written;

	/* validaton */
	if (infolen < sizeof(*istat))
		return NT_STATUS_INFO_LENGTH_MISMATCH;

	/* init */
	__ntapi->tt_aligned_block_memset(
		istat,0,sizeof(*istat));

	istat->hfile           = hfile;
	istat->dev_name_maxlen = (uint16_t)infolen - sizeof(*istat);

	/* sigh */
	if (buffer_size >= 65536)
		buffer_size = 65535;

	/* file index number */
	if (!(flags & NT_ISTAT_DEV_NAME_ONLY))
		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 (!(flags & NT_ISTAT_DEV_NAME_ONLY))
		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,
			&written)))
		return status;

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

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

	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_NOT_SUPPORTED;

	if ((sdev->strlen >= __DEVICE_MUP_PREFIX_LEN)
			&& (wch[8]=='M')
			&& (wch[9]=='u')
			&& (wch[10]=='p')
			&& (wch[11]=='\\')) {
		hash = __DEVICE_MUP_PREFIX_HASH;
		istat->flags |= NT_STATFS_MUP_DEVICE;

		wch_mark = &wch[12];
		wch      = wch_mark;

		for (; *wch!='\\'; )
			wch++;
		wch++;
	} else {
		wch_mark = &wch[8];
		wch      = wch_mark;
		hash     = __DEVICE_PATH_PREFIX_HASH;
	}

	wch_cap = sdev->buffer + (sdev->strlen / sizeof(wchar16_t));

	for (; wch<wch_cap && *wch!='\\'; )
		wch++;

	istat->obj_name_strlen = sdev->strlen;
	istat->obj_name_maxlen = istat->dev_name_maxlen;
	istat->dev_name_strlen = sizeof(uint16_t) * (uint16_t)(wch - sdev->buffer);
	istat->dev_name_hash   = __ntapi->tt_buffer_crc32(
					hash,wch_mark,
					sizeof(wchar16_t) * (wch - wch_mark));

	if (!(flags & NT_ISTAT_DEV_NAME_COPY))
		return NT_STATUS_SUCCESS;
	else if (istat->dev_name_maxlen < istat->dev_name_strlen)
		return NT_STATUS_BUFFER_TOO_SMALL;

	__ntapi->tt_memcpy_utf16(
		istat->dev_name,
		sdev->buffer,
		istat->dev_name_strlen);

	return status;
}