ramdisk.c File Reference

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

Include dependency graph for ramdisk.c:

Go to the source code of this file.

Functions
static ARC_STATUS	RamDiskClose (ULONG FileId)
static ARC_STATUS	RamDiskGetFileInformation (ULONG FileId, FILEINFORMATION *Information)
static ARC_STATUS	RamDiskOpen (CHAR *Path, OPENMODE OpenMode, ULONG *FileId)
static ARC_STATUS	RamDiskRead (ULONG FileId, VOID *Buffer, ULONG N, ULONG *Count)
static ARC_STATUS	RamDiskSeek (ULONG FileId, LARGE_INTEGER *Position, SEEKMODE SeekMode)
VOID NTAPI	RamDiskInitialize (VOID)
BOOLEAN NTAPI	RamDiskLoadVirtualFile (IN PCHAR FileName)

Variables
PVOID	gRamDiskBase
ULONG	gRamDiskSize
ULONG	gRamDiskOffset
static const DEVVTBL	RamDiskVtbl

Function Documentation

RamDiskClose()

static ARC_STATUS RamDiskClose ( ULONG  FileId )

static

Definition at line 24 of file ramdisk.c.

{
    //
    // Nothing to do
    //
    return ESUCCESS;
}

RamDiskGetFileInformation()

static ARC_STATUS RamDiskGetFileInformation ( ULONG  FileId, FILEINFORMATION *  Information  )

static

Definition at line 32 of file ramdisk.c.

{
    //
    // Give current seek offset and ram disk size to caller
    //
    RtlZeroMemory(Information, sizeof(FILEINFORMATION));
    Information->EndingAddress.LowPart = gRamDiskSize;
    Information->CurrentAddress.LowPart = gRamDiskOffset;

    return ESUCCESS;
}

RamDiskInitialize()

VOID NTAPI RamDiskInitialize

(

VOID

)

Definition at line 113 of file ramdisk.c.

{
    /* Register the RAMDISK device */
    FsRegisterDevice("ramdisk(0)", &RamDiskVtbl);
}

Referenced by ArmHwDetect(), and RamDiskLoadVirtualFile().

RamDiskLoadVirtualFile()

BOOLEAN NTAPI RamDiskLoadVirtualFile

(

IN PCHAR

FileName

)

Definition at line 121 of file ramdisk.c.

{
    PFILE RamFile;
    ULONG TotalRead, ChunkSize, Count;
    PCHAR MsgBuffer = "Loading RamDisk...";
    ULONG PercentPerChunk, Percent;
    FILEINFORMATION Information;
    LARGE_INTEGER Position;
    ARC_STATUS Status;

    //
    // Display progress
    //
    UiDrawBackdrop();
    UiDrawProgressBarCenter(1, 100, MsgBuffer);

    //
    // Try opening the ramdisk file
    //
    RamFile = FsOpenFile(FileName);
    if (!RamFile)
        return FALSE;

    //
    // Get the file size
    //
    Status = ArcGetFileInformation(RamFile, &Information);
    if (Status != ESUCCESS)
    {
        FsCloseFile(RamFile);
        return FALSE;
    }

    //
    // For now, limit RAM disks to 4GB
    //
    if (Information.EndingAddress.HighPart != 0)
    {
        UiMessageBox("RAM disk too big.");
        FsCloseFile(RamFile);
        return FALSE;
    }
    gRamDiskSize = Information.EndingAddress.LowPart;

    //
    // Allocate memory for it
    //
    ChunkSize = 8 * 1024 * 1024;
    if (gRamDiskSize < ChunkSize)
        Percent = PercentPerChunk = 0;
    else
        Percent = PercentPerChunk = 100 / (gRamDiskSize / ChunkSize);
    gRamDiskBase = MmAllocateMemoryWithType(gRamDiskSize, LoaderXIPRom);
    if (!gRamDiskBase)
    {
        UiMessageBox("Failed to allocate memory for RAM disk.");
        FsCloseFile(RamFile);
        return FALSE;
    }

    //
    // Read it in chunks
    //
    for (TotalRead = 0; TotalRead < gRamDiskSize; TotalRead += ChunkSize)
    {
        //
        // Check if we're at the last chunk
        //
        if ((gRamDiskSize - TotalRead) < ChunkSize)
        {
            //
            // Only need the actual data required
            //
            ChunkSize = gRamDiskSize - TotalRead;
        }

        //
        // Draw progress
        //
        UiDrawProgressBarCenter(Percent, 100, MsgBuffer);
        Percent += PercentPerChunk;

        //
        // Copy the contents
        //
        Position.HighPart = 0;
        Position.LowPart = TotalRead;
        Status = ArcSeek(RamFile, &Position, SeekAbsolute);
        if (Status == ESUCCESS)
        {
            Status = ArcRead(RamFile,
                             (PVOID)((ULONG_PTR)gRamDiskBase + TotalRead),
                             ChunkSize,
                             &Count);
        }

        //
        // Check for success
        //
        if (Status != ESUCCESS || Count != ChunkSize)
        {
            MmFreeMemory(gRamDiskBase);
            gRamDiskBase = NULL;
            gRamDiskSize = 0;
            FsCloseFile(RamFile);
            UiMessageBox("Failed to read RAM disk.");
            return FALSE;
        }
    }

    FsCloseFile(RamFile);

    /* Setup the RAMDISK device */
    RamDiskInitialize();

    return TRUE;
}

Referenced by LoadAndBootWindows(), and LoadReactOSSetup().

RamDiskOpen()

static ARC_STATUS RamDiskOpen ( CHAR *  Path, OPENMODE  OpenMode, ULONG *  FileId  )

static

Definition at line 44 of file ramdisk.c.

{
    //
    // Always return success, as contents are already in memory
    //
    return ESUCCESS;
}

RamDiskRead()

static ARC_STATUS RamDiskRead ( ULONG  FileId, VOID *  Buffer, ULONG  N, ULONG *  Count  )

static

Definition at line 52 of file ramdisk.c.

{
    PVOID StartAddress;

    //
    // Get actual pointer
    //
    StartAddress = (PVOID)((ULONG_PTR)gRamDiskBase + gRamDiskOffset);

    //
    // Don't allow reads past our image
    //
    if (gRamDiskOffset + N > gRamDiskSize)
    {
        *Count = 0;
        return EIO;
    }

    //
    // Do the read
    //
    RtlCopyMemory(Buffer, StartAddress, N);
    *Count = N;

    return ESUCCESS;
}

RamDiskSeek()

static ARC_STATUS RamDiskSeek ( ULONG  FileId, LARGE_INTEGER *  Position, SEEKMODE  SeekMode  )

static

Definition at line 79 of file ramdisk.c.

{
    //
    // Only accept absolute mode now
    //
    if (SeekMode != SeekAbsolute)
        return EINVAL;

    //
    // Check if we're in the ramdisk
    //
    if (Position->HighPart != 0)
        return EINVAL;
    if (Position->LowPart >= gRamDiskSize)
        return EINVAL;

    //
    // OK, remember seek position
    //
    gRamDiskOffset = Position->LowPart;

    return ESUCCESS;
}

Variable Documentation

gRamDiskBase

PVOID gRamDiskBase

Definition at line 18 of file ramdisk.c.

Referenced by CmdLineParse(), RamDiskLoadVirtualFile(), and RamDiskRead().

gRamDiskOffset

ULONG gRamDiskOffset

Definition at line 20 of file ramdisk.c.

Referenced by RamDiskGetFileInformation(), RamDiskRead(), and RamDiskSeek().

gRamDiskSize

ULONG gRamDiskSize

Definition at line 19 of file ramdisk.c.

Referenced by CmdLineParse(), RamDiskGetFileInformation(), RamDiskLoadVirtualFile(), RamDiskRead(), and RamDiskSeek().

RamDiskVtbl

const DEVVTBL RamDiskVtbl

static

Initial value:

= {
    RamDiskClose,
    RamDiskGetFileInformation,
    RamDiskOpen,
    RamDiskRead,
    RamDiskSeek,
}

Definition at line 103 of file ramdisk.c.

Referenced by RamDiskInitialize().