boot/freeldr/freeldr/disk/ramdisk.c

   1 /*
   2  * PROJECT:         ReactOS Boot Loader
   3  * LICENSE:         BSD - See COPYING.ARM in the top level directory
   4  * FILE:            boot/freeldr/freeldr/disk/ramdisk.c
   5  * PURPOSE:         Implements routines to support booting from a RAM Disk
   6  * PROGRAMMERS:     ReactOS Portable Systems Group
   7  *                  Hervé Poussineau
   8  */
   9
  10 /* INCLUDES *******************************************************************/
  11
  12 #include <freeldr.h>
  13
  14 #include <debug.h>
  15
  16 /* GLOBALS ********************************************************************/
  17
  18 PVOID gRamDiskBase;
  19 ULONG gRamDiskSize;
  20 ULONG gRamDiskOffset;
  21
  22 /* FUNCTIONS ******************************************************************/
  23
  24 static ARC_STATUS RamDiskClose(ULONG FileId)
  25 {
  26     //
  27     // Nothing to do
  28     //
  29     return ESUCCESS;
  30 }
  31
  32 static ARC_STATUS RamDiskGetFileInformation(ULONG FileId, FILEINFORMATION* Information)
  33 {
  34     //
  35     // Give current seek offset and ram disk size to caller
  36     //
  37     RtlZeroMemory(Information, sizeof(*Information));
  38     Information->EndingAddress.LowPart = gRamDiskSize;
  39     Information->CurrentAddress.LowPart = gRamDiskOffset;
  40
  41     return ESUCCESS;
  42 }
  43
  44 static ARC_STATUS RamDiskOpen(CHAR* Path, OPENMODE OpenMode, ULONG* FileId)
  45 {
  46     //
  47     // Always return success, as contents are already in memory
  48     //
  49     return ESUCCESS;
  50 }
  51
  52 static ARC_STATUS RamDiskRead(ULONG FileId, VOID* Buffer, ULONG N, ULONG* Count)
  53 {
  54     PVOID StartAddress;
  55
  56     //
  57     // Get actual pointer
  58     //
  59     StartAddress = (PVOID)((ULONG_PTR)gRamDiskBase + gRamDiskOffset);
  60
  61     //
  62     // Don't allow reads past our image
  63     //
  64     if (gRamDiskOffset + N > gRamDiskSize)
  65     {
  66         *Count = 0;
  67         return EIO;
  68     }
  69
  70     //
  71     // Do the read
  72     //
  73     RtlCopyMemory(Buffer, StartAddress, N);
  74     *Count = N;
  75
  76     return ESUCCESS;
  77 }
  78
  79 static ARC_STATUS RamDiskSeek(ULONG FileId, LARGE_INTEGER* Position, SEEKMODE SeekMode)
  80 {
  81     //
  82     // Only accept absolute mode now
  83     //
  84     if (SeekMode != SeekAbsolute)
  85         return EINVAL;
  86
  87     //
  88     // Check if we're in the ramdisk
  89     //
  90     if (Position->HighPart != 0)
  91         return EINVAL;
  92     if (Position->LowPart >= gRamDiskSize)
  93         return EINVAL;
  94
  95     //
  96     // OK, remember seek position
  97     //
  98     gRamDiskOffset = Position->LowPart;
  99
 100     return ESUCCESS;
 101 }
 102
 103 static const DEVVTBL RamDiskVtbl = {
 104     RamDiskClose,
 105     RamDiskGetFileInformation,
 106     RamDiskOpen,
 107     RamDiskRead,
 108     RamDiskSeek,
 109 };
 110
 111 VOID
 112 NTAPI
 113 RamDiskInitialize(VOID)
 114 {
 115     /* Register the RAMDISK device */
 116     FsRegisterDevice("ramdisk(0)", &RamDiskVtbl);
 117 }
 118
 119 BOOLEAN
 120 NTAPI
 121 RamDiskLoadVirtualFile(IN PCHAR FileName)
 122 {
 123     ULONG RamFileId;
 124     ULONG TotalRead, ChunkSize, Count;
 125     PCHAR MsgBuffer = "Loading RamDisk...";
 126     ULONG PercentPerChunk, Percent;
 127     FILEINFORMATION Information;
 128     LARGE_INTEGER Position;
 129     ARC_STATUS Status;
 130
 131     //
 132     // Display progress
 133     //
 134     UiDrawBackdrop();
 135     UiDrawProgressBarCenter(1, 100, MsgBuffer);
 136
 137     //
 138     // Try opening the ramdisk file
 139     //
 140     RamFileId = FsOpenFile(FileName);
 141     if (!RamFileId)
 142         return FALSE;
 143
 144     //
 145     // Get the file size
 146     //
 147     Status = ArcGetFileInformation(RamFileId, &Information);
 148     if (Status != ESUCCESS)
 149     {
 150         ArcClose(RamFileId);
 151         return FALSE;
 152     }
 153
 154     //
 155     // For now, limit RAM disks to 4GB
 156     //
 157     if (Information.EndingAddress.HighPart != 0)
 158     {
 159         UiMessageBox("RAM disk too big.");
 160         ArcClose(RamFileId);
 161         return FALSE;
 162     }
 163     gRamDiskSize = Information.EndingAddress.LowPart;
 164
 165     //
 166     // Allocate memory for it
 167     //
 168     ChunkSize = 8 * 1024 * 1024;
 169     if (gRamDiskSize < ChunkSize)
 170         Percent = PercentPerChunk = 0;
 171     else
 172         Percent = PercentPerChunk = 100 / (gRamDiskSize / ChunkSize);
 173     gRamDiskBase = MmAllocateMemoryWithType(gRamDiskSize, LoaderXIPRom);
 174     if (!gRamDiskBase)
 175     {
 176         UiMessageBox("Failed to allocate memory for RAM disk.");
 177         ArcClose(RamFileId);
 178         return FALSE;
 179     }
 180
 181     //
 182     // Read it in chunks
 183     //
 184     for (TotalRead = 0; TotalRead < gRamDiskSize; TotalRead += ChunkSize)
 185     {
 186         //
 187         // Check if we're at the last chunk
 188         //
 189         if ((gRamDiskSize - TotalRead) < ChunkSize)
 190         {
 191             //
 192             // Only need the actual data required
 193             //
 194             ChunkSize = gRamDiskSize - TotalRead;
 195         }
 196
 197         //
 198         // Draw progress
 199         //
 200         UiDrawProgressBarCenter(Percent, 100, MsgBuffer);
 201         Percent += PercentPerChunk;
 202
 203         //
 204         // Copy the contents
 205         //
 206         Position.HighPart = 0;
 207         Position.LowPart = TotalRead;
 208         Status = ArcSeek(RamFileId, &Position, SeekAbsolute);
 209         if (Status == ESUCCESS)
 210         {
 211             Status = ArcRead(RamFileId,
 212                              (PVOID)((ULONG_PTR)gRamDiskBase + TotalRead),
 213                              ChunkSize,
 214                              &Count);
 215         }
 216
 217         //
 218         // Check for success
 219         //
 220         if (Status != ESUCCESS || Count != ChunkSize)
 221         {
 222             MmFreeMemory(gRamDiskBase);
 223             gRamDiskBase = NULL;
 224             gRamDiskSize = 0;
 225             ArcClose(RamFileId);
 226             UiMessageBox("Failed to read RAM disk.");
 227             return FALSE;
 228         }
 229     }
 230
 231     ArcClose(RamFileId);
 232
 233     /* Setup the RAMDISK device */
 234     RamDiskInitialize();
 235
 236     return TRUE;
 237 }