code.delx.au - refind/blob - EfiLib/BdsTianoCore.c

   1 /** @file
   2   BDS Lib functions which relate with create or process the boot option.
   3
   4 Copyright (c) 2004 - 2011, Intel Corporation. All rights reserved.<BR>
   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 "../include/tiano_includes.h"
  16
  17 /**
  18   Build the boot#### or driver#### option from the VariableName, the
  19   build boot#### or driver#### will also be linked to BdsCommonOptionList.
  20
  21   @param  BdsCommonOptionList   The header of the boot#### or driver#### option
  22                                 link list
  23   @param  VariableName          EFI Variable name indicate if it is boot#### or
  24                                 driver####
  25
  26   @retval BDS_COMMON_OPTION     Get the option just been created
  27   @retval NULL                  Failed to get the new option
  28
  29 **/
  30 BDS_COMMON_OPTION *
  31 EFIAPI
  32 BdsLibVariableToOption (
  33   IN OUT LIST_ENTRY                   *BdsCommonOptionList,
  34   IN  CHAR16                          *VariableName
  35   )
  36 {
  37   UINT32                    Attribute;
  38   UINT16                    FilePathSize;
  39   UINT8                     *Variable;
  40   UINT8                     *TempPtr;
  41   UINTN                     VariableSize;
  42   EFI_DEVICE_PATH_PROTOCOL  *DevicePath;
  43   BDS_COMMON_OPTION         *Option;
  44   VOID                      *LoadOptions;
  45   UINT32                    LoadOptionsSize;
  46   CHAR16                    *Description;
  47   UINT8                     NumOff;
  48   EFI_GUID EfiGlobalVariableGuid     = { 0x8BE4DF61, 0x93CA, 0x11D2, { 0xAA, 0x0D, 0x00, 0xE0, 0x98, 0x03, 0x2B, 0x8C }};
  49
  50   //
  51   // Read the variable. We will never free this data.
  52   //
  53   Variable = BdsLibGetVariableAndSize (
  54               VariableName,
  55               &EfiGlobalVariableGuid,
  56               &VariableSize
  57               );
  58   if (Variable == NULL) {
  59     return NULL;
  60   }
  61   //
  62   // Notes: careful defined the variable of Boot#### or
  63   // Driver####, consider use some macro to abstract the code
  64   //
  65   //
  66   // Get the option attribute
  67   //
  68   TempPtr   =  Variable;
  69   Attribute =  *(UINT32 *) Variable;
  70   TempPtr   += sizeof (UINT32);
  71
  72   //
  73   // Get the option's device path size
  74   //
  75   FilePathSize =  *(UINT16 *) TempPtr;
  76   TempPtr      += sizeof (UINT16);
  77
  78   //
  79   // Get the option's description string
  80   //
  81   Description = (CHAR16 *) TempPtr;
  82
  83   //
  84   // Get the option's description string size
  85   //
  86   TempPtr     += StrSize ((CHAR16 *) TempPtr);
  87
  88   //
  89   // Get the option's device path
  90   //
  91   DevicePath =  (EFI_DEVICE_PATH_PROTOCOL *) TempPtr;
  92   TempPtr    += FilePathSize;
  93
  94   LoadOptions     = TempPtr;
  95   LoadOptionsSize = (UINT32) (VariableSize - (UINTN) (TempPtr - Variable));
  96
  97   //
  98   // The Console variables may have multiple device paths, so make
  99   // an Entry for each one.
 100   //
 101   Option = AllocateZeroPool (sizeof (BDS_COMMON_OPTION));
 102   if (Option == NULL) {
 103     return NULL;
 104   }
 105
 106   Option->Signature   = BDS_LOAD_OPTION_SIGNATURE;
 107   Option->DevicePath  = AllocateZeroPool (GetDevicePathSize (DevicePath));
 108   ASSERT(Option->DevicePath != NULL);
 109   CopyMem (Option->DevicePath, DevicePath, GetDevicePathSize (DevicePath));
 110
 111   Option->Attribute   = Attribute;
 112   Option->Description = AllocateZeroPool (StrSize (Description));
 113   ASSERT(Option->Description != NULL);
 114   CopyMem (Option->Description, Description, StrSize (Description));
 115
 116   Option->LoadOptions = AllocateZeroPool (LoadOptionsSize);
 117   ASSERT(Option->LoadOptions != NULL);
 118   CopyMem (Option->LoadOptions, LoadOptions, LoadOptionsSize);
 119   Option->LoadOptionsSize = LoadOptionsSize;
 120
 121   //
 122   // Get the value from VariableName Unicode string
 123   // since the ISO standard assumes ASCII equivalent abbreviations, we can be safe in converting this
 124   // Unicode stream to ASCII without any loss in meaning.
 125   //
 126   if (*VariableName == 'B') {
 127     NumOff = (UINT8) (sizeof (L"Boot") / sizeof(CHAR16) - 1);
 128     Option->BootCurrent = (UINT16) ((VariableName[NumOff]  -'0') * 0x1000);
 129     Option->BootCurrent = (UINT16) (Option->BootCurrent + ((VariableName[NumOff+1]-'0') * 0x100));
 130     Option->BootCurrent = (UINT16) (Option->BootCurrent +  ((VariableName[NumOff+2]-'0') * 0x10));
 131     Option->BootCurrent = (UINT16) (Option->BootCurrent + ((VariableName[NumOff+3]-'0')));
 132   }
 133   //
 134   // Insert active entry to BdsDeviceList
 135   //
 136   if ((Option->Attribute & LOAD_OPTION_ACTIVE) == LOAD_OPTION_ACTIVE) {
 137     InsertTailList (BdsCommonOptionList, &Option->Link);
 138     FreePool (Variable);
 139     return Option;
 140   }
 141
 142   FreePool (Variable);
 143   FreePool (Option);
 144   return NULL;
 145
 146 }
 147
 148
 149 /**
 150   Read the EFI variable (VendorGuid/Name) and return a dynamically allocated
 151   buffer, and the size of the buffer. If failure return NULL.
 152
 153   @param  Name                  String part of EFI variable name
 154   @param  VendorGuid            GUID part of EFI variable name
 155   @param  VariableSize          Returns the size of the EFI variable that was read
 156
 157   @return                       Dynamically allocated memory that contains a copy of the EFI variable
 158                                 Caller is responsible freeing the buffer.
 159   @retval NULL                  Variable was not read
 160
 161 **/
 162 VOID *
 163 EFIAPI
 164 BdsLibGetVariableAndSize (
 165   IN  CHAR16              *Name,
 166   IN  EFI_GUID            *VendorGuid,
 167   OUT UINTN               *VariableSize
 168   )
 169 {
 170   EFI_STATUS  Status;
 171   UINTN       BufferSize;
 172   VOID        *Buffer;
 173
 174   Buffer = NULL;
 175
 176   //
 177   // Pass in a zero size buffer to find the required buffer size.
 178   //
 179   BufferSize  = 0;
 180   Status      = gRT->GetVariable (Name, VendorGuid, NULL, &BufferSize, Buffer);
 181   if (Status == EFI_BUFFER_TOO_SMALL) {
 182     //
 183     // Allocate the buffer to return
 184     //
 185     Buffer = AllocateZeroPool (BufferSize);
 186     if (Buffer == NULL) {
 187       return NULL;
 188     }
 189     //
 190     // Read variable into the allocated buffer.
 191     //
 192     Status = gRT->GetVariable (Name, VendorGuid, NULL, &BufferSize, Buffer);
 193     if (EFI_ERROR (Status)) {
 194       BufferSize = 0;
 195     }
 196   }
 197
 198   *VariableSize = BufferSize;
 199   return Buffer;
 200 }
 201