iso.c File Reference

#include <freeldr.h>
#include <debug.h>

Include dependency graph for iso.c:

Go to the source code of this file.

Macros
#define	SECTORSIZE   2048
#define	TAG_ISO_BUFFER   'BosI'
#define	TAG_ISO_FILE   'FosI'

Functions
	DBG_DEFAULT_CHANNEL (FILESYSTEM)
static BOOLEAN	IsoSearchDirectoryBufferForFile (PVOID DirectoryBuffer, ULONG DirectoryLength, PCHAR FileName, PISO_FILE_INFO IsoFileInfoPointer)
static ARC_STATUS	IsoBufferDirectory (ULONG DeviceId, ULONG DirectoryStartSector, ULONG DirectoryLength, PVOID *pDirectoryBuffer)
static ARC_STATUS	IsoLookupFile (PCSTR FileName, ULONG DeviceId, PISO_FILE_INFO IsoFileInfoPointer)
ARC_STATUS	IsoClose (ULONG FileId)
ARC_STATUS	IsoGetFileInformation (ULONG FileId, FILEINFORMATION *Information)
ARC_STATUS	IsoOpen (CHAR *Path, OPENMODE OpenMode, ULONG *FileId)
ARC_STATUS	IsoRead (ULONG FileId, VOID *Buffer, ULONG N, ULONG *Count)
ARC_STATUS	IsoSeek (ULONG FileId, LARGE_INTEGER *Position, SEEKMODE SeekMode)
const DEVVTBL *	IsoMount (ULONG DeviceId)

Variables
const DEVVTBL	Iso9660FuncTable

Macro Definition Documentation

SECTORSIZE

#define SECTORSIZE   2048

Definition at line 27 of file iso.c.

TAG_ISO_BUFFER

#define TAG_ISO_BUFFER   'BosI'

Definition at line 28 of file iso.c.

TAG_ISO_FILE

#define TAG_ISO_FILE   'FosI'

Definition at line 29 of file iso.c.

Function Documentation

DBG_DEFAULT_CHANNEL()

DBG_DEFAULT_CHANNEL

(

FILESYSTEM

)

IsoBufferDirectory()

static ARC_STATUS IsoBufferDirectory ( ULONG  DeviceId, ULONG  DirectoryStartSector, ULONG  DirectoryLength, PVOID *  pDirectoryBuffer  )

static

Definition at line 99 of file iso.c.

{
    PVOID DirectoryBuffer;
    ULONG SectorCount;
    LARGE_INTEGER Position;
    ULONG Count;
    ARC_STATUS Status;

    TRACE("IsoBufferDirectory() DirectoryStartSector = %d DirectoryLength = %d\n", DirectoryStartSector, DirectoryLength);

    SectorCount = ROUND_UP(DirectoryLength, SECTORSIZE) / SECTORSIZE;
    TRACE("Trying to read (DirectoryCount) %d sectors.\n", SectorCount);

    //
    // Attempt to allocate memory for directory buffer
    //
    TRACE("Trying to allocate (DirectoryLength) %d bytes.\n", DirectoryLength);
    DirectoryBuffer = FrLdrTempAlloc(DirectoryLength, TAG_ISO_BUFFER);
    if (!DirectoryBuffer)
        return ENOMEM;

    //
    // Now read directory contents into DirectoryBuffer
    //
    Position.HighPart = 0;
    Position.LowPart = DirectoryStartSector * SECTORSIZE;
    Status = ArcSeek(DeviceId, &Position, SeekAbsolute);
    if (Status != ESUCCESS)
    {
        FrLdrTempFree(DirectoryBuffer, TAG_ISO_BUFFER);
        return Status;
    }
    Status = ArcRead(DeviceId, DirectoryBuffer, SectorCount * SECTORSIZE, &Count);
    if (Status != ESUCCESS || Count != SectorCount * SECTORSIZE)
    {
        FrLdrTempFree(DirectoryBuffer, TAG_ISO_BUFFER);
        return EIO;
    }

    *pDirectoryBuffer = DirectoryBuffer;
    return ESUCCESS;
}

Referenced by IsoLookupFile().

IsoClose()

ARC_STATUS IsoClose

(

ULONG

FileId

)

Definition at line 243 of file iso.c.

{
    PISO_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
    FrLdrTempFree(FileHandle, TAG_ISO_FILE);
    return ESUCCESS;
}

IsoGetFileInformation()

ARC_STATUS IsoGetFileInformation	(	ULONG	FileId,
		FILEINFORMATION *	Information
	)

Definition at line 250 of file iso.c.

{
    PISO_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);

    RtlZeroMemory(Information, sizeof(*Information));
    Information->EndingAddress.LowPart = FileHandle->FileSize;
    Information->CurrentAddress.LowPart = FileHandle->FilePointer;

    TRACE("IsoGetFileInformation(%lu) -> FileSize = %lu, FilePointer = 0x%lx\n",
          FileId, Information->EndingAddress.LowPart, Information->CurrentAddress.LowPart);

    return ESUCCESS;
}

IsoLookupFile()

static ARC_STATUS IsoLookupFile ( PCSTR  FileName, ULONG  DeviceId, PISO_FILE_INFO  IsoFileInfoPointer  )

static

Definition at line 150 of file iso.c.

{
    UCHAR Buffer[SECTORSIZE];
    PPVD Pvd = (PPVD)Buffer;
    UINT32        i;
    ULONG            NumberOfPathParts;
    CHAR        PathPart[261];
    PVOID        DirectoryBuffer;
    ULONG        DirectorySector;
    ULONG        DirectoryLength;
    ISO_FILE_INFO    IsoFileInfo;
    LARGE_INTEGER Position;
    ULONG Count;
    ARC_STATUS Status;

    TRACE("IsoLookupFile() FileName = %s\n", FileName);

    RtlZeroMemory(IsoFileInfoPointer, sizeof(ISO_FILE_INFO));
    RtlZeroMemory(&IsoFileInfo, sizeof(ISO_FILE_INFO));

    //
    // Read The Primary Volume Descriptor
    //
    Position.HighPart = 0;
    Position.LowPart = 16 * SECTORSIZE;
    Status = ArcSeek(DeviceId, &Position, SeekAbsolute);
    if (Status != ESUCCESS)
        return Status;
    Status = ArcRead(DeviceId, Pvd, SECTORSIZE, &Count);
    if (Status != ESUCCESS || Count < sizeof(PVD))
        return EIO;

    DirectorySector = Pvd->RootDirRecord.ExtentLocationL;
    DirectoryLength = Pvd->RootDirRecord.DataLengthL;

    //
    // Figure out how many sub-directories we are nested in
    //
    NumberOfPathParts = FsGetNumPathParts(FileName);

    //
    // Loop once for each part
    //
    for (i=0; i<NumberOfPathParts; i++)
    {
        //
        // Get first path part
        //
        FsGetFirstNameFromPath(PathPart, FileName);

        //
        // Advance to the next part of the path
        //
        for (; (*FileName != '\\') && (*FileName != '/') && (*FileName != '\0'); FileName++)
        {
        }
        FileName++;

        //
        // Buffer the directory contents
        //
        Status = IsoBufferDirectory(DeviceId, DirectorySector, DirectoryLength, &DirectoryBuffer);
        if (Status != ESUCCESS)
            return Status;

        //
        // Search for file name in directory
        //
        if (!IsoSearchDirectoryBufferForFile(DirectoryBuffer, DirectoryLength, PathPart, &IsoFileInfo))
        {
            FrLdrTempFree(DirectoryBuffer, TAG_ISO_BUFFER);
            return ENOENT;
        }

        FrLdrTempFree(DirectoryBuffer, TAG_ISO_BUFFER);

        //
        // If we have another sub-directory to go then
        // grab the start sector and file size
        //
        if ((i+1) < NumberOfPathParts)
        {
            DirectorySector = IsoFileInfo.FileStart;
            DirectoryLength = IsoFileInfo.FileSize;
        }

    }

    RtlCopyMemory(IsoFileInfoPointer, &IsoFileInfo, sizeof(ISO_FILE_INFO));

    return ESUCCESS;
}

Referenced by IsoOpen().

IsoMount()

const DEVVTBL* IsoMount

(

ULONG

DeviceId

)

Definition at line 495 of file iso.c.

{
    UCHAR Buffer[SECTORSIZE];
    PPVD Pvd = (PPVD)Buffer;
    LARGE_INTEGER Position;
    ULONG Count;
    ARC_STATUS Status;

    TRACE("Enter IsoMount(%lu)\n", DeviceId);

    //
    // Read The Primary Volume Descriptor
    //
    Position.HighPart = 0;
    Position.LowPart = 16 * SECTORSIZE;
    Status = ArcSeek(DeviceId, &Position, SeekAbsolute);
    if (Status != ESUCCESS)
        return NULL;
    Status = ArcRead(DeviceId, Pvd, SECTORSIZE, &Count);
    if (Status != ESUCCESS || Count < sizeof(PVD))
        return NULL;

    //
    // Check if PVD is valid. If yes, return ISO9660 function table
    //
    if (Pvd->VdType == 1 && RtlEqualMemory(Pvd->StandardId, "CD001", 5))
    {
        TRACE("IsoMount(%lu) success\n", DeviceId);
        return &Iso9660FuncTable;
    }

    return NULL;
}

Referenced by ArcOpen().

IsoOpen()

ARC_STATUS IsoOpen	(	CHAR *	Path,
		OPENMODE	OpenMode,
		ULONG *	FileId
	)

Definition at line 264 of file iso.c.

{
    ISO_FILE_INFO TempFileInfo;
    PISO_FILE_INFO FileHandle;
    ULONG DeviceId;
    ARC_STATUS Status;

    if (OpenMode != OpenReadOnly)
        return EACCES;

    DeviceId = FsGetDeviceId(*FileId);

    TRACE("IsoOpen() FileName = %s\n", Path);

    RtlZeroMemory(&TempFileInfo, sizeof(TempFileInfo));
    Status = IsoLookupFile(Path, DeviceId, &TempFileInfo);
    if (Status != ESUCCESS)
        return ENOENT;

    FileHandle = FrLdrTempAlloc(sizeof(ISO_FILE_INFO), TAG_ISO_FILE);
    if (!FileHandle)
        return ENOMEM;

    RtlCopyMemory(FileHandle, &TempFileInfo, sizeof(ISO_FILE_INFO));

    FsSetDeviceSpecific(*FileId, FileHandle);
    return ESUCCESS;
}

IsoRead()

ARC_STATUS IsoRead	(	ULONG	FileId,
		VOID *	Buffer,
		ULONG	N,
		ULONG *	Count
	)

Definition at line 293 of file iso.c.

{
    ARC_STATUS Status;
    PISO_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
    UCHAR SectorBuffer[SECTORSIZE];
    LARGE_INTEGER Position;
    ULONG DeviceId;
    ULONG SectorNumber;
    ULONG OffsetInSector;
    ULONG LengthInSector;
    ULONG NumberOfSectors;
    ULONG BytesRead;

    TRACE("IsoRead() Buffer = %p, N = %lu\n", Buffer, N);

    DeviceId = FsGetDeviceId(FileId);
    *Count = 0;

    //
    // If the user is trying to read past the end of
    // the file then return success with Count == 0.
    //
    if (FileHandle->FilePointer >= FileHandle->FileSize)
    {
        return ESUCCESS;
    }

    //
    // If the user is trying to read more than there is to read
    // then adjust the amount to read.
    //
    if (FileHandle->FilePointer + N > FileHandle->FileSize)
    {
        N = FileHandle->FileSize - FileHandle->FilePointer;
    }

    //
    // Ok, now we have to perform at most 3 calculations
    // I'll draw you a picture (using nifty ASCII art):
    //
    // CurrentFilePointer -+
    //                     |
    //    +----------------+
    //    |
    // +-----------+-----------+-----------+-----------+
    // | Sector  1 | Sector  2 | Sector  3 | Sector  4 |
    // +-----------+-----------+-----------+-----------+
    //    |                                    |
    //    +---------------+--------------------+
    //                    |
    // N -----------------+
    //
    // 1 - The first calculation (and read) will align
    //     the file pointer with the next sector
    //     boundary (if we are supposed to read that much)
    // 2 - The next calculation (and read) will read
    //     in all the full sectors that the requested
    //     amount of data would cover (in this case
    //     sectors 2 & 3).
    // 3 - The last calculation (and read) would read
    //     in the remainder of the data requested out of
    //     the last sector.
    //


    //
    // Only do the first read if we
    // aren't aligned on a cluster boundary
    //
    if (FileHandle->FilePointer % SECTORSIZE)
    {
        //
        // Do the math for our first read
        //
        SectorNumber = FileHandle->FileStart + (FileHandle->FilePointer / SECTORSIZE);
        OffsetInSector = FileHandle->FilePointer % SECTORSIZE;
        LengthInSector = min(N, SECTORSIZE - OffsetInSector);

        //
        // Now do the read and update Count, N, FilePointer, & Buffer
        //
        Position.HighPart = 0;
        Position.LowPart = SectorNumber * SECTORSIZE;
        Status = ArcSeek(DeviceId, &Position, SeekAbsolute);
        if (Status != ESUCCESS)
        {
            return Status;
        }
        Status = ArcRead(DeviceId, SectorBuffer, SECTORSIZE, &BytesRead);
        if (Status != ESUCCESS || BytesRead != SECTORSIZE)
        {
            return EIO;
        }
        RtlCopyMemory(Buffer, SectorBuffer + OffsetInSector, LengthInSector);
        *Count += LengthInSector;
        N -= LengthInSector;
        FileHandle->FilePointer += LengthInSector;
        Buffer = (PVOID)((ULONG_PTR)Buffer + LengthInSector);
    }

    //
    // Do the math for our second read (if any data left)
    //
    if (N > 0)
    {
        //
        // Determine how many full clusters we need to read
        //
        NumberOfSectors = (N / SECTORSIZE);

        SectorNumber = FileHandle->FileStart + (FileHandle->FilePointer / SECTORSIZE);

        //
        // Now do the read and update Count, N, FilePointer, & Buffer
        //
        Position.HighPart = 0;
        Position.LowPart = SectorNumber * SECTORSIZE;
        Status = ArcSeek(DeviceId, &Position, SeekAbsolute);
        if (Status != ESUCCESS)
        {
            return Status;
        }
        Status = ArcRead(DeviceId, Buffer, NumberOfSectors * SECTORSIZE, &BytesRead);
        if (Status != ESUCCESS || BytesRead != NumberOfSectors * SECTORSIZE)
        {
            return EIO;
        }

        *Count += NumberOfSectors * SECTORSIZE;
        N -= NumberOfSectors * SECTORSIZE;
        FileHandle->FilePointer += NumberOfSectors * SECTORSIZE;
        Buffer = (PVOID)((ULONG_PTR)Buffer + NumberOfSectors * SECTORSIZE);
    }

    //
    // Do the math for our third read (if any data left)
    //
    if (N > 0)
    {
        SectorNumber = FileHandle->FileStart + (FileHandle->FilePointer / SECTORSIZE);

        //
        // Now do the read and update Count, N, FilePointer, & Buffer
        //
        Position.HighPart = 0;
        Position.LowPart = SectorNumber * SECTORSIZE;
        Status = ArcSeek(DeviceId, &Position, SeekAbsolute);
        if (Status != ESUCCESS)
        {
            return Status;
        }
        Status = ArcRead(DeviceId, SectorBuffer, SECTORSIZE, &BytesRead);
        if (Status != ESUCCESS || BytesRead != SECTORSIZE)
        {
            return EIO;
        }
        RtlCopyMemory(Buffer, SectorBuffer, N);
        *Count += N;
        FileHandle->FilePointer += N;
    }

    TRACE("IsoRead() done\n");

    return ESUCCESS;
}

IsoSearchDirectoryBufferForFile()

static BOOLEAN IsoSearchDirectoryBufferForFile ( PVOID  DirectoryBuffer, ULONG  DirectoryLength, PCHAR  FileName, PISO_FILE_INFO  IsoFileInfoPointer  )

static

Definition at line 31 of file iso.c.

{
    PDIR_RECORD    Record;
    ULONG        Offset;
    ULONG i;
    CHAR Name[32];

    TRACE("IsoSearchDirectoryBufferForFile() DirectoryBuffer = 0x%x DirectoryLength = %d FileName = %s\n", DirectoryBuffer, DirectoryLength, FileName);

    RtlZeroMemory(Name, 32 * sizeof(UCHAR));

    Offset = 0;
    Record = (PDIR_RECORD)DirectoryBuffer;
    while (TRUE)
    {
        Offset = Offset + Record->RecordLength;
        Record = (PDIR_RECORD)((ULONG_PTR)DirectoryBuffer + Offset);

        if (Record->RecordLength == 0)
        {
            Offset = ROUND_UP(Offset, SECTORSIZE);
            Record = (PDIR_RECORD)((ULONG_PTR)DirectoryBuffer + Offset);
        }

        if (Offset >= DirectoryLength)
            return FALSE;

        if (Record->FileIdLength == 1 && Record->FileId[0] == 0)
        {
            TRACE("Name '.'\n");
        }
        else if (Record->FileIdLength == 1 && Record->FileId[0] == 1)
        {
            TRACE("Name '..'\n");
        }
        else
        {
            for (i = 0; i < Record->FileIdLength && Record->FileId[i] != ';'; i++)
                Name[i] = Record->FileId[i];
            Name[i] = 0;
            TRACE("Name '%s'\n", Name);

            if (strlen(FileName) == strlen(Name) && _stricmp(FileName, Name) == 0)
            {
                IsoFileInfoPointer->FileStart = Record->ExtentLocationL;
                IsoFileInfoPointer->FileSize = Record->DataLengthL;
                IsoFileInfoPointer->FilePointer = 0;
                IsoFileInfoPointer->Directory = !!(Record->FileFlags & 0x02);

                return TRUE;
            }

        }

        RtlZeroMemory(Name, 32 * sizeof(UCHAR));
    }

    return FALSE;
}

Referenced by IsoLookupFile().

IsoSeek()

ARC_STATUS IsoSeek	(	ULONG	FileId,
		LARGE_INTEGER *	Position,
		SEEKMODE	SeekMode
	)

Definition at line 459 of file iso.c.

{
    PISO_FILE_INFO FileHandle = FsGetDeviceSpecific(FileId);
    LARGE_INTEGER NewPosition = *Position;

    switch (SeekMode)
    {
        case SeekAbsolute:
            break;
        case SeekRelative:
            NewPosition.QuadPart += (ULONGLONG)FileHandle->FilePointer;
            break;
        default:
            ASSERT(FALSE);
            return EINVAL;
    }

    if (NewPosition.HighPart != 0)
        return EINVAL;
    if (NewPosition.LowPart >= FileHandle->FileSize)
        return EINVAL;

    FileHandle->FilePointer = NewPosition.LowPart;
    return ESUCCESS;
}

Variable Documentation

Iso9660FuncTable

const DEVVTBL Iso9660FuncTable

Initial value:

=
{
    IsoClose,
    IsoGetFileInformation,
    IsoOpen,
    IsoRead,
    IsoSeek,
    L"cdfs",
}

Definition at line 485 of file iso.c.

Referenced by IsoMount().