MdeModulePkg/Library/ResetUtilityLib/ResetUtility.c

   1 /** @file
   2   This contains the business logic for the module-specific Reset Helper functions.
   3
   4   Copyright (c) 2017 Intel Corporation. All rights reserved.<BR>
   5   Copyright (c) 2016 Microsoft Corporation. All rights reserved.<BR>
   6
   7   This program and the accompanying materials are licensed and made available under
   8   the terms and conditions of the BSD License that accompanies this distribution.
   9   The full text of the license may be found at
  10   http://opensource.org/licenses/bsd-license.php.
  11
  12   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  13   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14
  15 **/
  16 #include <Uefi.h>
  17 #include <Library/BaseLib.h>
  18 #include <Library/DebugLib.h>
  19 #include <Library/BaseMemoryLib.h>
  20 #include <Library/ResetSystemLib.h>
  21
  22 typedef struct {
  23   CHAR16 NullTerminator;
  24   GUID   ResetSubtype;
  25 } RESET_UTILITY_GUID_SPECIFIC_RESET_DATA;
  26
  27 /**
  28   This is a shorthand helper function to reset with a subtype so that
  29   the caller doesn't have to bother with a function that has half a dozen
  30   parameters.
  31
  32   This will generate a reset with status EFI_SUCCESS, a NULL string, and
  33   no custom data. The subtype will be formatted in such a way that it can be
  34   picked up by notification registrations and custom handlers.
  35
  36   NOTE: This call will fail if the architectural ResetSystem underpinnings
  37         are not initialized. For DXE, you can add gEfiResetArchProtocolGuid
  38         to your DEPEX.
  39
  40   @param[in]  ResetSubtype  GUID pointer for the reset subtype to be used.
  41
  42 **/
  43 VOID
  44 EFIAPI
  45 ResetPlatformSpecificGuid (
  46   IN CONST  GUID        *ResetSubtype
  47   )
  48 {
  49   RESET_UTILITY_GUID_SPECIFIC_RESET_DATA  ResetData;
  50
  51   ResetData.NullTerminator = CHAR_NULL;
  52   CopyGuid (&ResetData.ResetSubtype, ResetSubtype);
  53   ResetPlatformSpecific (sizeof (ResetData), &ResetData);
  54 }
  55
  56 /**
  57   This function examines the DataSize and ResetData parameters passed to
  58   to ResetSystem() and detemrines if the ResetData contains a Null-terminated
  59   Unicode string followed by a GUID specific subtype.  If the GUID specific
  60   subtype is present, then a pointer to the GUID value in ResetData is returned.
  61
  62   @param[in]  DataSize    The size, in bytes, of ResetData.
  63   @param[in]  ResetData   Pointer to the data buffer passed into ResetSystem().
  64
  65   @retval     Pointer     Pointer to the GUID value in ResetData.
  66   @retval     NULL        ResetData is NULL.
  67   @retval     NULL        ResetData does not start with a Null-terminated
  68                           Unicode string.
  69   @retval     NULL        A Null-terminated Unicode string is present, but there
  70                           are less than sizeof (GUID) bytes after the string.
  71   @retval     NULL        No subtype is found.
  72
  73 **/
  74 GUID *
  75 EFIAPI
  76 GetResetPlatformSpecificGuid (
  77   IN UINTN       DataSize,
  78   IN CONST VOID  *ResetData
  79   )
  80 {
  81   UINTN          ResetDataStringSize;
  82   GUID           *ResetSubtypeGuid;
  83
  84   //
  85   // Make sure parameters are valid
  86   //
  87   if ((ResetData == NULL) || (DataSize < sizeof (GUID))) {
  88     return NULL;
  89   }
  90
  91   //
  92   // Determine the number of bytes in the Null-terminated Unicode string
  93   // at the beginning of ResetData including the Null terminator.
  94   //
  95   ResetDataStringSize = StrnSizeS (ResetData, (DataSize / sizeof (CHAR16)));
  96
  97   //
  98   // Now, assuming that we have enough data for a GUID after the string, the
  99   // GUID should be immediately after the string itself.
 100   //
 101   if ((ResetDataStringSize < DataSize) && (DataSize - ResetDataStringSize) >= sizeof (GUID)) {
 102     ResetSubtypeGuid = (GUID *)((UINT8 *)ResetData + ResetDataStringSize);
 103     DEBUG ((DEBUG_VERBOSE, __FUNCTION__" - Detected reset subtype %g...\n", ResetSubtypeGuid));
 104     return ResetSubtypeGuid;
 105   }
 106   return NULL;
 107 }
 108
 109 /**
 110   This is a helper function that creates the reset data buffer that can be
 111   passed into ResetSystem().
 112
 113   The reset data buffer is returned in ResetData and contains ResetString
 114   followed by the ResetSubtype GUID followed by the ExtraData.
 115
 116   NOTE: Strings are internally limited by MAX_UINT16.
 117
 118   @param[in, out] ResetDataSize  On input, the size of the ResetData buffer. On
 119                                  output, either the total number of bytes
 120                                  copied, or the required buffer size.
 121   @param[in, out] ResetData      A pointer to the buffer in which to place the
 122                                  final structure.
 123   @param[in]      ResetSubtype   Pointer to the GUID specific subtype.  This
 124                                  parameter is optional and may be NULL.
 125   @param[in]      ResetString    Pointer to a Null-terminated Unicode string
 126                                  that describes the reset.  This parameter is
 127                                  optional and may be NULL.
 128   @param[in]      ExtraDataSize  The size, in bytes, of ExtraData buffer.
 129   @param[in]      ExtraData      Pointer to a buffer of extra data.  This
 130                                  parameter is optional and may be NULL.
 131
 132   @retval     RETURN_SUCCESS             ResetDataSize and ResetData are updated.
 133   @retval     RETURN_INVALID_PARAMETER   ResetDataSize is NULL.
 134   @retval     RETURN_INVALID_PARAMETER   ResetData is NULL.
 135   @retval     RETURN_INVALID_PARAMETER   ExtraData was provided without a
 136                                          ResetSubtype. This is not supported by the
 137                                          UEFI spec.
 138   @retval     RETURN_BUFFER_TOO_SMALL    An insufficient buffer was provided.
 139                                          ResetDataSize is updated with minimum size
 140                                          required.
 141 **/
 142 RETURN_STATUS
 143 EFIAPI
 144 BuildResetData (
 145   IN OUT   UINTN     *ResetDataSize,
 146   IN OUT   VOID      *ResetData,
 147   IN CONST GUID      *ResetSubtype  OPTIONAL,
 148   IN CONST CHAR16    *ResetString   OPTIONAL,
 149   IN       UINTN     ExtraDataSize  OPTIONAL,
 150   IN CONST VOID      *ExtraData     OPTIONAL
 151   )
 152 {
 153   UINTN  ResetStringSize;
 154   UINTN  ResetDataBufferSize;
 155   UINT8  *Data;
 156
 157   //
 158   // If the size return pointer is NULL.
 159   //
 160   if (ResetDataSize == NULL) {
 161     return RETURN_INVALID_PARAMETER;
 162   }
 163   //
 164   // If extra data is indicated, but pointer is NULL.
 165   //
 166   if (ExtraDataSize > 0 && ExtraData == NULL) {
 167     return RETURN_INVALID_PARAMETER;
 168   }
 169   //
 170   // If extra data is indicated, but no subtype GUID is supplied.
 171   //
 172   if (ResetSubtype == NULL && ExtraDataSize > 0) {
 173     return RETURN_INVALID_PARAMETER;
 174   }
 175
 176   //
 177   // Determine the final string.
 178   //
 179   if (ResetString == NULL) {
 180     ResetString = L"";     // Use an empty string.
 181   }
 182
 183   //
 184   // Calculate the total buffer required for ResetData.
 185   //
 186   ResetStringSize     = StrnSizeS (ResetString, MAX_UINT16);
 187   ResetDataBufferSize = ResetStringSize + ExtraDataSize;
 188   if (ResetSubtype != NULL) {
 189     ResetDataBufferSize += sizeof (GUID);
 190   }
 191
 192   //
 193   // At this point, if the buffer isn't large enough (or if
 194   // the buffer is NULL) we cannot proceed.
 195   //
 196   if (*ResetDataSize < ResetDataBufferSize) {
 197     *ResetDataSize = ResetDataBufferSize;
 198     return RETURN_BUFFER_TOO_SMALL;
 199   }
 200   *ResetDataSize = ResetDataBufferSize;
 201   if (ResetData == NULL) {
 202     return RETURN_INVALID_PARAMETER;
 203   }
 204
 205   //
 206   // Fill in ResetData with ResetString, the ResetSubtype GUID, and extra data
 207   //
 208   Data = (UINT8 *)ResetData;
 209   CopyMem (Data, ResetString, ResetStringSize);
 210   Data += ResetStringSize;
 211   if (ResetSubtype != NULL) {
 212     CopyMem (Data, ResetSubtype, sizeof (GUID));
 213     Data += sizeof (GUID);
 214   }
 215   if (ExtraDataSize > 0) {
 216     CopyMem (Data, ExtraData, ExtraDataSize);
 217   }
 218
 219   return RETURN_SUCCESS;
 220 }