common/filesystem/filesystemext.cpp

c1c9242f0046150566414e1f222cb667e03e605evboxsync/* $Id$ */
c1c9242f0046150566414e1f222cb667e03e605evboxsync/** @file
c1c9242f0046150566414e1f222cb667e03e605evboxsync * IPRT Filesystem API (FileSys) - ext2/3 format.
c1c9242f0046150566414e1f222cb667e03e605evboxsync */
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync/*
c1c9242f0046150566414e1f222cb667e03e605evboxsync * Copyright (C) 2012 Oracle Corporation
c1c9242f0046150566414e1f222cb667e03e605evboxsync *
c1c9242f0046150566414e1f222cb667e03e605evboxsync * This file is part of VirtualBox Open Source Edition (OSE), as
c1c9242f0046150566414e1f222cb667e03e605evboxsync * available from http://www.virtualbox.org. This file is free software;
c1c9242f0046150566414e1f222cb667e03e605evboxsync * you can redistribute it and/or modify it under the terms of the GNU
c1c9242f0046150566414e1f222cb667e03e605evboxsync * General Public License (GPL) as published by the Free Software
c1c9242f0046150566414e1f222cb667e03e605evboxsync * Foundation, in version 2 as it comes in the "COPYING" file of the
c1c9242f0046150566414e1f222cb667e03e605evboxsync * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
c1c9242f0046150566414e1f222cb667e03e605evboxsync * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
c1c9242f0046150566414e1f222cb667e03e605evboxsync *
c1c9242f0046150566414e1f222cb667e03e605evboxsync * The contents of this file may alternatively be used under the terms
c1c9242f0046150566414e1f222cb667e03e605evboxsync * of the Common Development and Distribution License Version 1.0
c1c9242f0046150566414e1f222cb667e03e605evboxsync * (CDDL) only, as it comes in the "COPYING.CDDL" file of the
c1c9242f0046150566414e1f222cb667e03e605evboxsync * VirtualBox OSE distribution, in which case the provisions of the
c1c9242f0046150566414e1f222cb667e03e605evboxsync * CDDL are applicable instead of those of the GPL.
c1c9242f0046150566414e1f222cb667e03e605evboxsync *
c1c9242f0046150566414e1f222cb667e03e605evboxsync * You may elect to license modified versions of this file under the
c1c9242f0046150566414e1f222cb667e03e605evboxsync * terms and conditions of either the GPL or the CDDL or both.
c1c9242f0046150566414e1f222cb667e03e605evboxsync */
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync/*******************************************************************************
c1c9242f0046150566414e1f222cb667e03e605evboxsync*   Header Files                                                               *
c1c9242f0046150566414e1f222cb667e03e605evboxsync*******************************************************************************/
c1c9242f0046150566414e1f222cb667e03e605evboxsync#define LOG_GROUP LOG_GROUP_DEFAULT
c1c9242f0046150566414e1f222cb667e03e605evboxsync#include <iprt/types.h>
c1c9242f0046150566414e1f222cb667e03e605evboxsync#include <iprt/assert.h>
c1c9242f0046150566414e1f222cb667e03e605evboxsync#include <iprt/mem.h>
c1c9242f0046150566414e1f222cb667e03e605evboxsync#include <iprt/filesystem.h>
c1c9242f0046150566414e1f222cb667e03e605evboxsync#include <iprt/string.h>
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync#include <iprt/vfs.h>
c1c9242f0046150566414e1f222cb667e03e605evboxsync#include "internal/filesystem.h"
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync/*******************************************************************************
c1c9242f0046150566414e1f222cb667e03e605evboxsync*   Structures and Typedefs                                                    *
c1c9242f0046150566414e1f222cb667e03e605evboxsync*******************************************************************************/
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync/*
c1c9242f0046150566414e1f222cb667e03e605evboxsync * The filesystem structures are from http://wiki.osdev.org/Ext2 and
c1c9242f0046150566414e1f222cb667e03e605evboxsync * http://www.nongnu.org/ext2-doc/ext2.html
c1c9242f0046150566414e1f222cb667e03e605evboxsync */
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync/**
c1c9242f0046150566414e1f222cb667e03e605evboxsync * Ext superblock.
c1c9242f0046150566414e1f222cb667e03e605evboxsync *
c1c9242f0046150566414e1f222cb667e03e605evboxsync * Everything is stored little endian on the disk.
c1c9242f0046150566414e1f222cb667e03e605evboxsync */
c1c9242f0046150566414e1f222cb667e03e605evboxsync#pragma pack(1)
c1c9242f0046150566414e1f222cb667e03e605evboxsynctypedef struct ExtSuperBlock
c1c9242f0046150566414e1f222cb667e03e605evboxsync{
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Total number of inodes in the filesystem. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    cInodesTotal;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Total number of blocks in the filesystem. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    cBlocksTotal;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Number of blocks reserved for the super user. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    cBlocksRsvdForSuperUser;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Total number of unallocated blocks. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    cBlocksUnallocated;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Total number of unallocated inodes. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    cInodesUnallocated;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Block number of block containing the superblock. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    iBlockOfSuperblock;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Number of bits to shift 1024 to the left to get the block size */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    cBitsShiftLeftBlockSize;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Number of bits to shift 1024 to the left to get the fragment size */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    cBitsShiftLeftFragmentSize;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Number of blocks in each block group. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    cBlocksPerGroup;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Number of fragments in each block group. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    cFragmentsPerBlockGroup;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Number of inodes in each block group. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    cInodesPerBlockGroup;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Last mount time. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    u32LastMountTime;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Last written time. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    u32LastWrittenTime;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Number of times the volume was mounted since the last check. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint16_t    cMountsSinceLastCheck;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Number of mounts allowed before a consistency check. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint16_t    cMaxMountsUntilCheck;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Signature to identify a ext2 volume. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint16_t    u16Signature;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** State of the filesystem (clean/errors) */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint16_t    u16FilesystemState;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** What to do on an error. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint16_t    u16ActionOnError;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Minor version field. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint16_t    u16VersionMinor;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Time of last check. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    u32LastCheckTime;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Interval between consistency checks. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    u32CheckInterval;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Operating system ID of the filesystem creator. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    u32OsIdCreator;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Major version field. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    u32VersionMajor;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** User ID that is allowed to use reserved blocks. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint16_t    u16UidReservedBlocks;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Group ID that is allowed to use reserved blocks. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint16_t    u16GidReservedBlocks;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Reserved fields. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint8_t     abReserved[940];
c1c9242f0046150566414e1f222cb667e03e605evboxsync} ExtSuperBlock;
c1c9242f0046150566414e1f222cb667e03e605evboxsync#pragma pack()
c1c9242f0046150566414e1f222cb667e03e605evboxsyncAssertCompileSize(ExtSuperBlock, 1024);
c1c9242f0046150566414e1f222cb667e03e605evboxsync/** Pointer to an ext super block. */
c1c9242f0046150566414e1f222cb667e03e605evboxsynctypedef ExtSuperBlock *PExtSuperBlock;
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync/** Ext2 signature. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync#define RTFILESYSTEM_EXT2_SIGNATURE    (0xef53)
c1c9242f0046150566414e1f222cb667e03e605evboxsync/** Clean filesystem state. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync#define RTFILESYSTEM_EXT2_STATE_CLEAN  (0x0001)
c1c9242f0046150566414e1f222cb667e03e605evboxsync/** Error filesystem state. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync#define RTFILESYSTEM_EXT2_STATE_ERRORS (0x0002)
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync/**
c1c9242f0046150566414e1f222cb667e03e605evboxsync * Block group descriptor.
c1c9242f0046150566414e1f222cb667e03e605evboxsync */
c1c9242f0046150566414e1f222cb667e03e605evboxsync#pragma pack(1)
c1c9242f0046150566414e1f222cb667e03e605evboxsynctypedef struct BlockGroupDesc
c1c9242f0046150566414e1f222cb667e03e605evboxsync{
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Block address of the block bitmap. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    offBlockBitmap;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Block address of the inode bitmap. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    offInodeBitmap;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Start block address of the inode table. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t    offInodeTable;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Number of unallocated blocks in group. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint16_t    cBlocksUnallocated;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Number of unallocated inodes in group. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint16_t    cInodesUnallocated;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Number of directories in the group. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint16_t    cDirectories;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Padding. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint16_t    u16Padding;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Reserved. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint8_t     abReserved[12];
c1c9242f0046150566414e1f222cb667e03e605evboxsync} BlockGroupDesc;
c1c9242f0046150566414e1f222cb667e03e605evboxsync#pragma pack()
c1c9242f0046150566414e1f222cb667e03e605evboxsyncAssertCompileSize(BlockGroupDesc, 32);
c1c9242f0046150566414e1f222cb667e03e605evboxsync/** Pointer to an ext block group descriptor. */
c1c9242f0046150566414e1f222cb667e03e605evboxsynctypedef BlockGroupDesc *PBlockGroupDesc;
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync/**
c1c9242f0046150566414e1f222cb667e03e605evboxsync * Cached block group descriptor data.
c1c9242f0046150566414e1f222cb667e03e605evboxsync */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsynctypedef struct RTFILESYSTEMEXTBLKGRP
c1c9242f0046150566414e1f222cb667e03e605evboxsync{
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Start offset (in bytes and from the start of the disk). */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint64_t    offStart;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Last offset in the block group (inclusive). */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint64_t    offLast;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Block bitmap - variable in size (depends on the block size
c1c9242f0046150566414e1f222cb667e03e605evboxsync     * and number of blocks per group). */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint8_t     abBlockBitmap[1];
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync} RTFILESYSTEMEXTBLKGRP;
c1c9242f0046150566414e1f222cb667e03e605evboxsync/** Pointer to block group descriptor data. */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsynctypedef RTFILESYSTEMEXTBLKGRP *PRTFILESYSTEMEXTBLKGRP;
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync/**
c1c9242f0046150566414e1f222cb667e03e605evboxsync * Ext2/3 filesystem data.
c1c9242f0046150566414e1f222cb667e03e605evboxsync */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsynctypedef struct RTFILESYSTEMEXT
c1c9242f0046150566414e1f222cb667e03e605evboxsync{
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    /** VFS file handle. */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    RTVFSFILE                 hVfsFile;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Block number of the superblock. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint32_t                  iSbBlock;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Size of one block. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    size_t                    cbBlock;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Number of blocks in one group. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    unsigned                  cBlocksPerGroup;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Number of blocks groups in the volume. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync    unsigned                  cBlockGroups;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    /** Cached block group descriptor data. */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    PRTFILESYSTEMEXTBLKGRP    pBlkGrpDesc;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync} RTFILESYSTEMEXT;
c1c9242f0046150566414e1f222cb667e03e605evboxsync/** Pointer to the ext filesystem data. */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsynctypedef RTFILESYSTEMEXT *PRTFILESYSTEMEXT;
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync/*******************************************************************************
c1c9242f0046150566414e1f222cb667e03e605evboxsync*   Methods                                                                    *
c1c9242f0046150566414e1f222cb667e03e605evboxsync*******************************************************************************/
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync/**
c1c9242f0046150566414e1f222cb667e03e605evboxsync * Loads the block descriptor of the given block group from the medium.
c1c9242f0046150566414e1f222cb667e03e605evboxsync *
c1c9242f0046150566414e1f222cb667e03e605evboxsync * @returns IPRT status code.
c1c9242f0046150566414e1f222cb667e03e605evboxsync * @param   pThis    EXT filesystem instance data.
c1c9242f0046150566414e1f222cb667e03e605evboxsync * @param   iBlkGrp  Block group number to load.
c1c9242f0046150566414e1f222cb667e03e605evboxsync */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsyncstatic int rtFsExtLoadBlkGrpDesc(PRTFILESYSTEMEXT pThis, uint32_t iBlkGrp)
c1c9242f0046150566414e1f222cb667e03e605evboxsync{
c1c9242f0046150566414e1f222cb667e03e605evboxsync    int rc = VINF_SUCCESS;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    PRTFILESYSTEMEXTBLKGRP pBlkGrpDesc = pThis->pBlkGrpDesc;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    uint64_t offRead = (pThis->iSbBlock + 1) * pThis->cbBlock;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    BlockGroupDesc BlkDesc;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    size_t cbBlockBitmap;
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync    cbBlockBitmap = pThis->cBlocksPerGroup / 8;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    if (pThis->cBlocksPerGroup % 8)
c1c9242f0046150566414e1f222cb667e03e605evboxsync        cbBlockBitmap++;
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync    if (!pBlkGrpDesc)
c1c9242f0046150566414e1f222cb667e03e605evboxsync    {
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        size_t cbBlkDesc = RT_OFFSETOF(RTFILESYSTEMEXTBLKGRP, abBlockBitmap[cbBlockBitmap]);
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        pBlkGrpDesc = (PRTFILESYSTEMEXTBLKGRP)RTMemAllocZ(cbBlkDesc);
c1c9242f0046150566414e1f222cb667e03e605evboxsync        if (!pBlkGrpDesc)
c1c9242f0046150566414e1f222cb667e03e605evboxsync            return VERR_NO_MEMORY;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    }
c1c9242f0046150566414e1f222cb667e03e605evboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    rc = RTVfsFileReadAt(pThis->hVfsFile, offRead, &BlkDesc, sizeof(BlkDesc), NULL);
c1c9242f0046150566414e1f222cb667e03e605evboxsync    if (RT_SUCCESS(rc))
c1c9242f0046150566414e1f222cb667e03e605evboxsync    {
c1c9242f0046150566414e1f222cb667e03e605evboxsync        pBlkGrpDesc->offStart = pThis->iSbBlock + (uint64_t)iBlkGrp * pThis->cBlocksPerGroup * pThis->cbBlock;
c1c9242f0046150566414e1f222cb667e03e605evboxsync        pBlkGrpDesc->offLast  = pBlkGrpDesc->offStart + pThis->cBlocksPerGroup * pThis->cbBlock;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        rc = RTVfsFileReadAt(pThis->hVfsFile, BlkDesc.offBlockBitmap * pThis->cbBlock,
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync                             &pBlkGrpDesc->abBlockBitmap[0], cbBlockBitmap, NULL);
c1c9242f0046150566414e1f222cb667e03e605evboxsync    }
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync    pThis->pBlkGrpDesc = pBlkGrpDesc;
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync    return rc;
c1c9242f0046150566414e1f222cb667e03e605evboxsync}
c1c9242f0046150566414e1f222cb667e03e605evboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsyncstatic bool rtFsExtIsBlockRangeInUse(PRTFILESYSTEMEXTBLKGRP pBlkGrpDesc,
854203c3afd42e567982d205e1046c8531d099a2vboxsync                                     uint32_t offBlockStart, size_t cBlocks)
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync{
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    bool fUsed = false;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    while (cBlocks)
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    {
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        uint32_t idxByte = offBlockStart / 8;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        uint32_t iBit = offBlockStart % 8;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        if (pBlkGrpDesc->abBlockBitmap[idxByte] & RT_BIT(iBit))
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        {
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync            fUsed = true;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync            break;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        }
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        cBlocks--;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        offBlockStart++;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    }
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    return fUsed;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync}
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsyncstatic DECLCALLBACK(int) rtFsExtProbe(RTVFSFILE hVfsFile, uint32_t *puScore)
c1c9242f0046150566414e1f222cb667e03e605evboxsync{
c1c9242f0046150566414e1f222cb667e03e605evboxsync    int rc = VINF_SUCCESS;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    uint64_t cbMedium = 0;
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync    *puScore = RTFILESYSTEM_MATCH_SCORE_UNSUPPORTED;
c1c9242f0046150566414e1f222cb667e03e605evboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    rc = RTVfsFileGetSize(hVfsFile, &cbMedium);
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    if (RT_SUCCESS(rc))
c1c9242f0046150566414e1f222cb667e03e605evboxsync    {
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        if (cbMedium >= 2*sizeof(ExtSuperBlock))
c1c9242f0046150566414e1f222cb667e03e605evboxsync        {
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync            ExtSuperBlock SuperBlock;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync            rc = RTVfsFileReadAt(hVfsFile, 1024, &SuperBlock, sizeof(ExtSuperBlock), NULL);
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync            if (RT_SUCCESS(rc))
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync            {
c1c9242f0046150566414e1f222cb667e03e605evboxsync#if defined(RT_BIGENDIAN)
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync                /** @todo: Convert to host endianess. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync#endif
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync                if (SuperBlock.u16Signature == RTFILESYSTEM_EXT2_SIGNATURE)
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync                    *puScore = RTFILESYSTEM_MATCH_SCORE_SUPPORTED;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync            }
c1c9242f0046150566414e1f222cb667e03e605evboxsync        }
c1c9242f0046150566414e1f222cb667e03e605evboxsync    }
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync    return rc;
c1c9242f0046150566414e1f222cb667e03e605evboxsync}
c1c9242f0046150566414e1f222cb667e03e605evboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsyncstatic DECLCALLBACK(int) rtFsExtInit(void *pvThis, RTVFSFILE hVfsFile)
c1c9242f0046150566414e1f222cb667e03e605evboxsync{
c1c9242f0046150566414e1f222cb667e03e605evboxsync    int rc = VINF_SUCCESS;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    PRTFILESYSTEMEXT pThis = (PRTFILESYSTEMEXT)pvThis;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    ExtSuperBlock SuperBlock;
c1c9242f0046150566414e1f222cb667e03e605evboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    pThis->hVfsFile    = hVfsFile;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    pThis->pBlkGrpDesc = NULL;
c1c9242f0046150566414e1f222cb667e03e605evboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    rc = RTVfsFileReadAt(hVfsFile, 1024, &SuperBlock, sizeof(ExtSuperBlock), NULL);
c1c9242f0046150566414e1f222cb667e03e605evboxsync    if (RT_SUCCESS(rc))
c1c9242f0046150566414e1f222cb667e03e605evboxsync    {
c1c9242f0046150566414e1f222cb667e03e605evboxsync#if defined(RT_BIGENDIAN)
c1c9242f0046150566414e1f222cb667e03e605evboxsync        /** @todo: Convert to host endianess. */
c1c9242f0046150566414e1f222cb667e03e605evboxsync#endif
c1c9242f0046150566414e1f222cb667e03e605evboxsync        if (SuperBlock.u16FilesystemState == RTFILESYSTEM_EXT2_STATE_ERRORS)
c1c9242f0046150566414e1f222cb667e03e605evboxsync            rc = VERR_FILESYSTEM_CORRUPT;
c1c9242f0046150566414e1f222cb667e03e605evboxsync        else
c1c9242f0046150566414e1f222cb667e03e605evboxsync        {
c1c9242f0046150566414e1f222cb667e03e605evboxsync            pThis->iSbBlock = SuperBlock.iBlockOfSuperblock;
c1c9242f0046150566414e1f222cb667e03e605evboxsync            pThis->cbBlock = 1024 << SuperBlock.cBitsShiftLeftBlockSize;
c1c9242f0046150566414e1f222cb667e03e605evboxsync            pThis->cBlocksPerGroup = SuperBlock.cBlocksPerGroup;
c1c9242f0046150566414e1f222cb667e03e605evboxsync            pThis->cBlockGroups = SuperBlock.cBlocksTotal / pThis->cBlocksPerGroup;
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync            /* Load first block group descriptor. */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync            rc = rtFsExtLoadBlkGrpDesc(pThis, 0);
c1c9242f0046150566414e1f222cb667e03e605evboxsync        }
c1c9242f0046150566414e1f222cb667e03e605evboxsync    }
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync    return rc;
c1c9242f0046150566414e1f222cb667e03e605evboxsync}
c1c9242f0046150566414e1f222cb667e03e605evboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsyncstatic DECLCALLBACK(void) rtFsExtDestroy(void *pvThis)
c1c9242f0046150566414e1f222cb667e03e605evboxsync{
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    PRTFILESYSTEMEXT pThis = (PRTFILESYSTEMEXT)pvThis;
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync    if (pThis->pBlkGrpDesc)
c1c9242f0046150566414e1f222cb667e03e605evboxsync        RTMemFree(pThis->pBlkGrpDesc);
c1c9242f0046150566414e1f222cb667e03e605evboxsync}
c1c9242f0046150566414e1f222cb667e03e605evboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsyncstatic DECLCALLBACK(int) rtFsExtOpenRoot(void *pvThis, PRTVFSDIR phVfsDir)
c1c9242f0046150566414e1f222cb667e03e605evboxsync{
350953fa71e4942666d270cfac998be645fae487vboxsync    NOREF(pvThis);
350953fa71e4942666d270cfac998be645fae487vboxsync    NOREF(phVfsDir);
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    return VERR_NOT_IMPLEMENTED;
c1c9242f0046150566414e1f222cb667e03e605evboxsync}
c1c9242f0046150566414e1f222cb667e03e605evboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsyncstatic DECLCALLBACK(int) rtFsExtIsRangeInUse(void *pvThis, RTFOFF off, size_t cb,
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync                                             bool *pfUsed)
c1c9242f0046150566414e1f222cb667e03e605evboxsync{
c1c9242f0046150566414e1f222cb667e03e605evboxsync    int rc = VINF_SUCCESS;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    uint64_t offStart = (uint64_t)off;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    PRTFILESYSTEMEXT pThis = (PRTFILESYSTEMEXT)pvThis;
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    *pfUsed = false;
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync    while (cb > 0)
c1c9242f0046150566414e1f222cb667e03e605evboxsync    {
c1c9242f0046150566414e1f222cb667e03e605evboxsync        bool fUsed;
c1c9242f0046150566414e1f222cb667e03e605evboxsync        uint32_t offBlockStart = (uint32_t)(offStart / pThis->cbBlock);
c1c9242f0046150566414e1f222cb667e03e605evboxsync        uint32_t iBlockGroup = (offBlockStart - pThis->iSbBlock) / pThis->cBlocksPerGroup;
c1c9242f0046150566414e1f222cb667e03e605evboxsync        uint32_t offBlockRelStart = offBlockStart - iBlockGroup * pThis->cBlocksPerGroup;
c1c9242f0046150566414e1f222cb667e03e605evboxsync        size_t cbThis = 0;
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync        if (   offStart < pThis->pBlkGrpDesc->offStart
c1c9242f0046150566414e1f222cb667e03e605evboxsync            || offStart > pThis->pBlkGrpDesc->offLast)
c1c9242f0046150566414e1f222cb667e03e605evboxsync        {
c1c9242f0046150566414e1f222cb667e03e605evboxsync            /* Load new block descriptor. */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync            rc = rtFsExtLoadBlkGrpDesc(pThis, iBlockGroup);
c1c9242f0046150566414e1f222cb667e03e605evboxsync            if (RT_FAILURE(rc))
c1c9242f0046150566414e1f222cb667e03e605evboxsync                break;
c1c9242f0046150566414e1f222cb667e03e605evboxsync        }
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync        cbThis = RT_MIN(cb, pThis->pBlkGrpDesc->offLast - offStart + 1);
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        fUsed = rtFsExtIsBlockRangeInUse(pThis->pBlkGrpDesc, offBlockRelStart,
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync                                         cbThis / pThis->cbBlock +
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync                                         (cbThis % pThis->cbBlock ? 1 : 0));
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync        if (fUsed)
c1c9242f0046150566414e1f222cb667e03e605evboxsync        {
c1c9242f0046150566414e1f222cb667e03e605evboxsync            *pfUsed = true;
c1c9242f0046150566414e1f222cb667e03e605evboxsync            break;
c1c9242f0046150566414e1f222cb667e03e605evboxsync        }
c1c9242f0046150566414e1f222cb667e03e605evboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        cb       -= cbThis;
c1c9242f0046150566414e1f222cb667e03e605evboxsync        offStart += cbThis;
c1c9242f0046150566414e1f222cb667e03e605evboxsync    }
c1c9242f0046150566414e1f222cb667e03e605evboxsync
c1c9242f0046150566414e1f222cb667e03e605evboxsync    return rc;
c1c9242f0046150566414e1f222cb667e03e605evboxsync}
c1c9242f0046150566414e1f222cb667e03e605evboxsync
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsyncDECL_HIDDEN_CONST(RTFILESYSTEMDESC) const g_rtFsExt =
c1c9242f0046150566414e1f222cb667e03e605evboxsync{
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    /** cbFs */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    sizeof(RTFILESYSTEMEXT),
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    /** VfsOps */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    {
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        /** uVersion. */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        RTVFSOPS_VERSION,
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        /** fFeatures */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        0,
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        /** pszName */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        "ExtVfsOps",
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        /** pfnDestroy */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        rtFsExtDestroy,
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        /** pfnOpenRoot */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        rtFsExtOpenRoot,
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        /** pfnIsRangeInUse */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        rtFsExtIsRangeInUse,
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        /** uEndMarker */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync        RTVFSOPS_VERSION
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    },
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    /** pfnProbe */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    rtFsExtProbe,
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    /** pfnInit */
54d2d2606d7c83a456819cd038a73e0f9a600ca4vboxsync    rtFsExtInit
c1c9242f0046150566414e1f222cb667e03e605evboxsync};
c1c9242f0046150566414e1f222cb667e03e605evboxsync