ArmPlatformPkg/FileSystem/BootMonFs/BootMonFsReadWrite.c

   1 /** @file
   2 *
   3 *  Copyright (c) 2012-2014, ARM Limited. All rights reserved.
   4 *
   5 *  This program and the accompanying materials
   6 *  are licensed and made available under the terms and conditions of the BSD License
   7 *  which accompanies this distribution.  The full text of the license may be found at
   8 *  http://opensource.org/licenses/bsd-license.php
   9 *
  10 *  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11 *  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12 *
  13 **/
  14
  15 #include <Protocol/SimpleFileSystem.h>
  16 #include <Library/UefiLib.h>
  17 #include <Library/BaseMemoryLib.h>
  18 #include <Library/MemoryAllocationLib.h>
  19 #include <Library/DebugLib.h>
  20
  21 #include "BootMonFsInternal.h"
  22
  23 EFIAPI
  24 EFI_STATUS
  25 BootMonFsReadFile (
  26   IN EFI_FILE_PROTOCOL  *This,
  27   IN OUT UINTN          *BufferSize,
  28   OUT VOID              *Buffer
  29   )
  30 {
  31   BOOTMON_FS_INSTANCE   *Instance;
  32   BOOTMON_FS_FILE       *File;
  33   EFI_DISK_IO_PROTOCOL  *DiskIo;
  34   EFI_BLOCK_IO_MEDIA    *Media;
  35   UINT64                FileStart;
  36   EFI_STATUS            Status;
  37   UINTN                 RemainingFileSize;
  38
  39   // Ensure the file has been written in Flash before reading it.
  40   // This keeps the code simple and avoids having to manage a non-flushed file.
  41   BootMonFsFlushFile (This);
  42
  43   File = BOOTMON_FS_FILE_FROM_FILE_THIS (This);
  44   if (File == NULL) {
  45     return EFI_INVALID_PARAMETER;
  46   }
  47
  48   Instance = File->Instance;
  49   DiskIo = Instance->DiskIo;
  50   Media = Instance->Media;
  51   FileStart = (Media->LowestAlignedLba + File->HwDescription.BlockStart) * Media->BlockSize;
  52
  53   if (File->Position >= File->HwDescription.Region[0].Size) {
  54     // The entire file has been read
  55     *BufferSize = 0;
  56     return EFI_DEVICE_ERROR;
  57   }
  58
  59   // This driver assumes that the entire file is in region 0.
  60   RemainingFileSize = File->HwDescription.Region[0].Size - File->Position;
  61
  62   // If read would go past end of file, truncate the read
  63   if (*BufferSize > RemainingFileSize) {
  64     *BufferSize = RemainingFileSize;
  65   }
  66
  67   Status = DiskIo->ReadDisk (
  68                     DiskIo,
  69                     Media->MediaId,
  70                     FileStart + File->Position,
  71                     *BufferSize,
  72                     Buffer
  73                     );
  74   if (EFI_ERROR (Status)) {
  75     *BufferSize = 0;
  76   }
  77
  78   File->Position += *BufferSize;
  79
  80   return Status;
  81 }
  82
  83 // Inserts an entry into the write chain
  84 EFIAPI
  85 EFI_STATUS
  86 BootMonFsWriteFile (
  87   IN EFI_FILE_PROTOCOL  *This,
  88   IN OUT UINTN          *BufferSize,
  89   IN VOID               *Buffer
  90   )
  91 {
  92   BOOTMON_FS_FILE         *File;
  93   BOOTMON_FS_FILE_REGION  *Region;
  94
  95   File = BOOTMON_FS_FILE_FROM_FILE_THIS (This);
  96   if (File == NULL) {
  97     return EFI_INVALID_PARAMETER;
  98   }
  99
 100   if (!(File->OpenMode & EFI_FILE_MODE_WRITE)) {
 101     return EFI_ACCESS_DENIED;
 102   }
 103
 104   // Allocate and initialize the memory region
 105   Region = (BOOTMON_FS_FILE_REGION*)AllocateZeroPool (sizeof (BOOTMON_FS_FILE_REGION));
 106   if (Region == NULL) {
 107     return EFI_OUT_OF_RESOURCES;
 108   }
 109
 110   Region->Buffer  = AllocateCopyPool (*BufferSize, Buffer);
 111   if (Region->Buffer == NULL) {
 112     FreePool (Region);
 113     return EFI_OUT_OF_RESOURCES;
 114   }
 115
 116   Region->Size    = *BufferSize;
 117
 118   Region->Offset = File->Position;
 119
 120   InsertTailList (&File->RegionToFlushLink, &Region->Link);
 121
 122   File->Position += *BufferSize;
 123
 124   return EFI_SUCCESS;
 125 }
 126
 127 EFIAPI
 128 EFI_STATUS
 129 BootMonFsSetPosition (
 130   IN EFI_FILE_PROTOCOL  *This,
 131   IN UINT64             Position
 132   )
 133 {
 134   BOOTMON_FS_FILE         *File;
 135
 136   File = BOOTMON_FS_FILE_FROM_FILE_THIS (This);
 137
 138   // UEFI Spec section 12.5:
 139   // "Seeking to position 0xFFFFFFFFFFFFFFFF causes the current position to
 140   //  be set to the end of the file."
 141   if (Position == 0xFFFFFFFFFFFFFFFF) {
 142     File->Position = BootMonFsGetImageLength (File);
 143   } else {
 144     // NB: Seeking past the end of the file is valid.
 145     File->Position = Position;
 146   }
 147
 148   return EFI_SUCCESS;
 149 }
 150
 151 EFIAPI
 152 EFI_STATUS
 153 BootMonFsGetPosition (
 154   IN  EFI_FILE_PROTOCOL *This,
 155   OUT UINT64            *Position
 156   ) {
 157   BOOTMON_FS_FILE         *File;
 158
 159   File = BOOTMON_FS_FILE_FROM_FILE_THIS (This);
 160
 161   *Position = File->Position;
 162   return EFI_SUCCESS;
 163 }