mirror of
https://github.com/marketideas/qasm.git
synced 2024-12-28 06:29:58 +00:00
508 lines
14 KiB
C++
508 lines
14 KiB
C++
/*
|
|
* CiderPress
|
|
* Copyright (C) 2007 by faddenSoft, LLC. All Rights Reserved.
|
|
* See the file LICENSE for distribution terms.
|
|
*/
|
|
/*
|
|
* Implementation of the Windows FAT filesystem.
|
|
*
|
|
* Right now we just try to identify that a disk is in a PC format rather
|
|
* than Apple II. The trick here is to figure out whether block 0 is a
|
|
* Master Boot Record or merely a Boot Sector.
|
|
*/
|
|
#include "StdAfx.h"
|
|
#include "DiskImgPriv.h"
|
|
|
|
|
|
/*
|
|
* ===========================================================================
|
|
* DiskFSFAT
|
|
* ===========================================================================
|
|
*/
|
|
|
|
const int kBlkSize = 512;
|
|
const long kBootBlock = 0;
|
|
const uint16_t kSignature = 0xaa55; // MBR or boot sector
|
|
const int kSignatureOffset = 0x1fe;
|
|
const uint8_t kOpcodeMumble = 0x33; // seen on 2nd drive
|
|
const uint8_t kOpcodeBranch = 0xeb;
|
|
const uint8_t kOpcodeSetInt = 0xfa;
|
|
|
|
typedef struct PartitionTableEntry {
|
|
uint8_t driveNum; // dl (0x80 or 0x00)
|
|
uint8_t startHead; // dh
|
|
uint8_t startSector; // cl (&0x3f=sector, +two hi bits cyl)
|
|
uint8_t startCylinder; // ch (low 8 bits of 10-bit cylinder)
|
|
uint8_t type; // partition type
|
|
uint8_t endHead; // dh
|
|
uint8_t endSector; // cl
|
|
uint8_t endCylinder; // ch
|
|
uint32_t startLBA; // in blocks
|
|
uint32_t size; // in blocks
|
|
} PartitionTableEntry;
|
|
|
|
/*
|
|
* Definition of a Master Boot Record, which is block 0 of a physical volume.
|
|
*/
|
|
typedef struct DiskFSFAT::MasterBootRecord {
|
|
/*
|
|
* Begins immediately with code, usually 0xfa (set interrupt flag) or
|
|
* 0xeb (relative branch).
|
|
*/
|
|
uint8_t firstByte;
|
|
|
|
/*
|
|
* Partition table starts at 0x1be. Four entries, each 16 bytes.
|
|
*/
|
|
PartitionTableEntry parTab[4];
|
|
} MasterBootRecord;
|
|
|
|
/*
|
|
* Definition of a boot sector, which is block 0 of a logical volume.
|
|
*/
|
|
typedef struct DiskFSFAT::BootSector {
|
|
/*
|
|
* The first few bytes of the boot sector is called the BIOS Parameter
|
|
* Block, or BPB.
|
|
*/
|
|
uint8_t jump[3]; // usually EB XX 90
|
|
uint8_t oemName[8]; // e.g. "MSWIN4.1" or "MSDOS5.0"
|
|
uint16_t bytesPerSector; // usually (always?) 512
|
|
uint8_t sectPerCluster;
|
|
uint16_t reservedSectors;
|
|
uint8_t numFAT;
|
|
uint16_t numRootDirEntries;
|
|
uint16_t numSectors; // if set, ignore numSectorsHuge
|
|
uint8_t mediaType;
|
|
uint16_t numFATSectors;
|
|
uint16_t sectorsPerTrack;
|
|
uint16_t numHeads;
|
|
uint32_t numHiddenSectors;
|
|
uint32_t numSectorsHuge; // only if numSectors==0
|
|
/*
|
|
* This next part can start immediately after the above (at 0x24) for
|
|
* FAT12/FAT16, or somewhat later (0x42) for FAT32. It doesn't seem
|
|
* to exist for NTFS. Probably safest to assume it doesn't exist.
|
|
*
|
|
* The only way to be sure of what we're dealing with is to know the
|
|
* partition type, but if this is our block 0 then we can't know what
|
|
* that is.
|
|
*/
|
|
uint8_t driveNum;
|
|
uint8_t reserved;
|
|
uint8_t signature; // 0x29
|
|
uint32_t volumeID;
|
|
uint8_t volumeLabel[11]; // e.g. "FUBAR "
|
|
uint8_t fileSysType[8]; // e.g. "FAT12 "
|
|
|
|
/*
|
|
* Code follows. Signature 0xaa55 in the last two bytes.
|
|
*/
|
|
} BootSector;
|
|
|
|
// some values for MediaType
|
|
enum MediaType {
|
|
kMediaTypeLarge = 0xf0, // 1440KB or 2800KB 3.5" disk
|
|
kMediaTypeHardDrive = 0xf8,
|
|
kMediaTypeMedium = 0xf9, // 720KB 3.5" disk or 1.2MB 5.25" disk
|
|
kMediaTypeSmall = 0xfd, // 360KB 5.25" disk
|
|
};
|
|
|
|
|
|
/*
|
|
* Unpack the MBR.
|
|
*
|
|
* Returns "true" if this looks like an MBR, "false" otherwise.
|
|
*/
|
|
/*static*/ bool DiskFSFAT::UnpackMBR(const uint8_t* buf, MasterBootRecord* pOut)
|
|
{
|
|
const uint8_t* ptr;
|
|
int i;
|
|
|
|
pOut->firstByte = buf[0x00];
|
|
|
|
ptr = &buf[0x1be];
|
|
for (i = 0; i < 4; i++) {
|
|
pOut->parTab[i].driveNum = ptr[0x00];
|
|
pOut->parTab[i].startHead = ptr[0x01];
|
|
pOut->parTab[i].startSector = ptr[0x02];
|
|
pOut->parTab[i].startCylinder = ptr[0x03];
|
|
pOut->parTab[i].type = ptr[0x04];
|
|
pOut->parTab[i].endHead = ptr[0x05];
|
|
pOut->parTab[i].endSector = ptr[0x06];
|
|
pOut->parTab[i].endCylinder = ptr[0x07];
|
|
pOut->parTab[i].startLBA = GetLongLE(&ptr[0x08]);
|
|
pOut->parTab[i].size = GetLongLE(&ptr[0x0c]);
|
|
|
|
ptr += 16;
|
|
}
|
|
|
|
if (pOut->firstByte != kOpcodeBranch &&
|
|
pOut->firstByte != kOpcodeSetInt &&
|
|
pOut->firstByte != kOpcodeMumble)
|
|
return false;
|
|
bool foundActive = false;
|
|
for (i = 0; i < 4; i++) {
|
|
if (pOut->parTab[i].driveNum == 0x80)
|
|
foundActive = true;
|
|
else if (pOut->parTab[i].driveNum != 0x00)
|
|
return false; // must be 0x00 or 0x80
|
|
}
|
|
// CFFA cards don't seem to set the "active" flag
|
|
if (false && !foundActive)
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Unpack the boot sector.
|
|
*
|
|
* Returns "true" if this looks like a boot sector, "false" otherwise.
|
|
*/
|
|
/*static*/ bool DiskFSFAT::UnpackBootSector(const uint8_t* buf, BootSector* pOut)
|
|
{
|
|
memcpy(pOut->jump, &buf[0x00], sizeof(pOut->jump));
|
|
memcpy(pOut->oemName, &buf[0x03], sizeof(pOut->oemName));
|
|
pOut->bytesPerSector = GetShortLE(&buf[0x0b]);
|
|
pOut->sectPerCluster = buf[0x0d];
|
|
pOut->reservedSectors = GetShortLE(&buf[0x0e]);
|
|
pOut->numFAT = buf[0x10];
|
|
pOut->numRootDirEntries = GetShortLE(&buf[0x11]);
|
|
pOut->numSectors = GetShortLE(&buf[0x13]);
|
|
pOut->mediaType = buf[0x15];
|
|
pOut->numFATSectors = GetShortLE(&buf[0x16]);
|
|
pOut->sectorsPerTrack = GetShortLE(&buf[0x18]);
|
|
pOut->numHeads = GetShortLE(&buf[0x1a]);
|
|
pOut->numHiddenSectors = GetLongLE(&buf[0x1c]);
|
|
pOut->numSectorsHuge = GetLongLE(&buf[0x20]);
|
|
|
|
if (pOut->jump[0] != kOpcodeBranch && pOut->jump[0] != kOpcodeSetInt)
|
|
return false;
|
|
if (pOut->bytesPerSector != 512)
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* See if this looks like a FAT volume.
|
|
*/
|
|
/*static*/ DIError DiskFSFAT::TestImage(DiskImg* pImg, DiskImg::SectorOrder imageOrder)
|
|
{
|
|
DIError dierr = kDIErrNone;
|
|
uint8_t blkBuf[kBlkSize];
|
|
MasterBootRecord mbr;
|
|
BootSector bs;
|
|
|
|
dierr = pImg->ReadBlockSwapped(kBootBlock, blkBuf, imageOrder,
|
|
DiskImg::kSectorOrderProDOS);
|
|
if (dierr != kDIErrNone)
|
|
goto bail;
|
|
|
|
/*
|
|
* Both MBR and boot sectors have the same signature in block 0.
|
|
*/
|
|
if (GetShortLE(&blkBuf[kSignatureOffset]) != kSignature) {
|
|
dierr = kDIErrFilesystemNotFound;
|
|
goto bail;
|
|
}
|
|
|
|
/*
|
|
* Decode it as an MBR and as a partition table. Figure out which
|
|
* one makes sense. If neither make sense, fail.
|
|
*/
|
|
bool hasMBR, hasBS;
|
|
hasMBR = UnpackMBR(blkBuf, &mbr);
|
|
hasBS = UnpackBootSector(blkBuf, &bs);
|
|
LOGI(" FAT hasMBR=%d hasBS=%d", hasMBR, hasBS);
|
|
|
|
if (!hasMBR && !hasBS) {
|
|
dierr = kDIErrFilesystemNotFound;
|
|
goto bail;
|
|
}
|
|
if (hasMBR) {
|
|
LOGI(" FAT partition table found:");
|
|
for (int i = 0; i < 4; i++) {
|
|
LOGI(" %d: type=0x%02x start LBA=%-9u size=%u",
|
|
i, mbr.parTab[i].type,
|
|
mbr.parTab[i].startLBA, mbr.parTab[i].size);
|
|
}
|
|
}
|
|
if (hasBS) {
|
|
LOGI(" FAT boot sector found:");
|
|
LOGI(" OEMName is '%.8s'", bs.oemName);
|
|
}
|
|
|
|
// looks good!
|
|
|
|
bail:
|
|
return dierr;
|
|
}
|
|
|
|
/*
|
|
* Test to see if the image is a FAT disk.
|
|
*/
|
|
/*static*/ DIError DiskFSFAT::TestFS(DiskImg* pImg, DiskImg::SectorOrder* pOrder,
|
|
DiskImg::FSFormat* pFormat, FSLeniency leniency)
|
|
{
|
|
/* must be block format, should be at least 360K */
|
|
if (!pImg->GetHasBlocks() || pImg->GetNumBlocks() < kExpectedMinBlocks)
|
|
return kDIErrFilesystemNotFound;
|
|
if (pImg->GetIsEmbedded()) // don't look for FAT inside CFFA!
|
|
return kDIErrFilesystemNotFound;
|
|
|
|
DiskImg::SectorOrder ordering[DiskImg::kSectorOrderMax];
|
|
|
|
DiskImg::GetSectorOrderArray(ordering, *pOrder);
|
|
|
|
for (int i = 0; i < DiskImg::kSectorOrderMax; i++) {
|
|
if (ordering[i] == DiskImg::kSectorOrderUnknown)
|
|
continue;
|
|
if (TestImage(pImg, ordering[i]) == kDIErrNone) {
|
|
*pOrder = ordering[i];
|
|
*pFormat = DiskImg::kFormatMSDOS;
|
|
return kDIErrNone;
|
|
}
|
|
}
|
|
|
|
LOGI(" FAT didn't find valid FS");
|
|
return kDIErrFilesystemNotFound;
|
|
}
|
|
|
|
/*
|
|
* Get things rolling.
|
|
*/
|
|
DIError DiskFSFAT::Initialize(void)
|
|
{
|
|
DIError dierr = kDIErrNone;
|
|
|
|
strcpy(fVolumeName, "[MS-DOS]"); // max 11 chars
|
|
strcpy(fVolumeID, "FATxx [MS-DOS]");
|
|
|
|
// take the easy way out
|
|
fTotalBlocks = fpImg->GetNumBlocks();
|
|
|
|
CreateFakeFile();
|
|
|
|
SetVolumeUsageMap();
|
|
|
|
return dierr;
|
|
}
|
|
|
|
|
|
/*
|
|
* Blank out the volume usage map.
|
|
*/
|
|
void DiskFSFAT::SetVolumeUsageMap(void)
|
|
{
|
|
VolumeUsage::ChunkState cstate;
|
|
long block;
|
|
|
|
fVolumeUsage.Create(fpImg->GetNumBlocks());
|
|
|
|
cstate.isUsed = true;
|
|
cstate.isMarkedUsed = true;
|
|
cstate.purpose = VolumeUsage::kChunkPurposeUnknown;
|
|
|
|
for (block = fTotalBlocks-1; block >= 0; block--)
|
|
fVolumeUsage.SetChunkState(block, &cstate);
|
|
}
|
|
|
|
|
|
/*
|
|
* Fill a buffer with some interesting stuff, and add it to the file list.
|
|
*/
|
|
void DiskFSFAT::CreateFakeFile(void)
|
|
{
|
|
A2FileFAT* pFile;
|
|
char buf[768]; // currently running about 430
|
|
static const char* kFormatMsg =
|
|
"The FAT12/16/32 and NTFS filesystems are not supported. CiderPress knows\r\n"
|
|
"how to recognize MS-DOS and Windows volumes so that it can identify\r\n"
|
|
"PC data on removable media, but it does not know how to view or extract\r\n"
|
|
"files from them.\r\n"
|
|
"\r\n"
|
|
"Some information about this FAT volume:\r\n"
|
|
"\r\n"
|
|
" Volume name : '%s'\r\n"
|
|
" Volume size : %ld blocks (%.2fMB)\r\n"
|
|
"\r\n"
|
|
"(CiderPress limits itself to 8GB, so larger volume sizes may not be shown.)\r\n"
|
|
;
|
|
long capacity;
|
|
|
|
capacity = fTotalBlocks;
|
|
|
|
memset(buf, 0, sizeof(buf));
|
|
snprintf(buf, NELEM(buf)-1, kFormatMsg,
|
|
fVolumeName,
|
|
capacity,
|
|
(double) capacity / 2048.0);
|
|
|
|
pFile = new A2FileFAT(this);
|
|
pFile->SetFakeFile(buf, strlen(buf));
|
|
strcpy(pFile->fFileName, "(not supported)");
|
|
|
|
AddFileToList(pFile);
|
|
}
|
|
|
|
|
|
/*
|
|
* ===========================================================================
|
|
* A2FileFAT
|
|
* ===========================================================================
|
|
*/
|
|
|
|
/*
|
|
* Dump the contents of the A2File structure.
|
|
*/
|
|
void A2FileFAT::Dump(void) const
|
|
{
|
|
LOGD("A2FileFAT '%s'", fFileName);
|
|
}
|
|
|
|
/*
|
|
* Not a whole lot to do.
|
|
*/
|
|
DIError A2FileFAT::Open(A2FileDescr** ppOpenFile, bool readOnly,
|
|
bool rsrcFork /*=false*/)
|
|
{
|
|
A2FDFAT* pOpenFile = NULL;
|
|
|
|
if (fpOpenFile != NULL)
|
|
return kDIErrAlreadyOpen;
|
|
if (rsrcFork)
|
|
return kDIErrForkNotFound;
|
|
assert(readOnly == true);
|
|
|
|
pOpenFile = new A2FDFAT(this);
|
|
|
|
fpOpenFile = pOpenFile;
|
|
*ppOpenFile = pOpenFile;
|
|
|
|
return kDIErrNone;
|
|
}
|
|
|
|
|
|
/*
|
|
* ===========================================================================
|
|
* A2FDFAT
|
|
* ===========================================================================
|
|
*/
|
|
|
|
/*
|
|
* Read a chunk of data from the fake file.
|
|
*/
|
|
DIError A2FDFAT::Read(void* buf, size_t len, size_t* pActual)
|
|
{
|
|
LOGD(" FAT reading %lu bytes from '%s' (offset=%ld)",
|
|
(unsigned long) len, fpFile->GetPathName(), (long) fOffset);
|
|
|
|
A2FileFAT* pFile = (A2FileFAT*) fpFile;
|
|
|
|
/* don't allow them to read past the end of the file */
|
|
if (fOffset + (long)len > pFile->fLength) {
|
|
if (pActual == NULL)
|
|
return kDIErrDataUnderrun;
|
|
len = (size_t) (pFile->fLength - fOffset);
|
|
}
|
|
if (pActual != NULL)
|
|
*pActual = len;
|
|
|
|
memcpy(buf, pFile->GetFakeFileBuf(), len);
|
|
|
|
fOffset += len;
|
|
|
|
return kDIErrNone;
|
|
}
|
|
|
|
/*
|
|
* Write data at the current offset.
|
|
*/
|
|
DIError A2FDFAT::Write(const void* buf, size_t len, size_t* pActual)
|
|
{
|
|
return kDIErrNotSupported;
|
|
}
|
|
|
|
/*
|
|
* Seek to a new offset.
|
|
*/
|
|
DIError A2FDFAT::Seek(di_off_t offset, DIWhence whence)
|
|
{
|
|
di_off_t fileLen = ((A2FileFAT*) fpFile)->fLength;
|
|
|
|
switch (whence) {
|
|
case kSeekSet:
|
|
if (offset < 0 || offset > fileLen)
|
|
return kDIErrInvalidArg;
|
|
fOffset = offset;
|
|
break;
|
|
case kSeekEnd:
|
|
if (offset > 0 || offset < -fileLen)
|
|
return kDIErrInvalidArg;
|
|
fOffset = fileLen + offset;
|
|
break;
|
|
case kSeekCur:
|
|
if (offset < -fOffset ||
|
|
offset >= (fileLen - fOffset))
|
|
{
|
|
return kDIErrInvalidArg;
|
|
}
|
|
fOffset += offset;
|
|
break;
|
|
default:
|
|
assert(false);
|
|
return kDIErrInvalidArg;
|
|
}
|
|
|
|
assert(fOffset >= 0 && fOffset <= fileLen);
|
|
return kDIErrNone;
|
|
}
|
|
|
|
/*
|
|
* Return current offset.
|
|
*/
|
|
di_off_t A2FDFAT::Tell(void)
|
|
{
|
|
return fOffset;
|
|
}
|
|
|
|
/*
|
|
* Release file state, and tell our parent to destroy us.
|
|
*/
|
|
DIError A2FDFAT::Close(void)
|
|
{
|
|
fpFile->CloseDescr(this);
|
|
return kDIErrNone;
|
|
}
|
|
|
|
/*
|
|
* Return the #of sectors/blocks in the file.
|
|
*/
|
|
long A2FDFAT::GetSectorCount(void) const
|
|
{
|
|
A2FileFAT* pFile = (A2FileFAT*) fpFile;
|
|
return (long) ((pFile->fLength+255) / 256);
|
|
}
|
|
|
|
long A2FDFAT::GetBlockCount(void) const
|
|
{
|
|
A2FileFAT* pFile = (A2FileFAT*) fpFile;
|
|
return (long) ((pFile->fLength+511) / 512);
|
|
}
|
|
|
|
/*
|
|
* Return the Nth track/sector in this file.
|
|
*/
|
|
DIError A2FDFAT::GetStorage(long sectorIdx, long* pTrack, long* pSector) const
|
|
{
|
|
return kDIErrNotSupported;
|
|
}
|
|
|
|
/*
|
|
* Return the Nth 512-byte block in this file.
|
|
*/
|
|
DIError A2FDFAT::GetStorage(long blockIdx, long* pBlock) const
|
|
{
|
|
return kDIErrNotSupported;
|
|
}
|