CloverBootloader/Library/MachoLib/Relocations.c
2019-10-04 23:32:02 +03:00

159 lines
3.6 KiB
C

/** @file
Provides services for Relocations.
Copyright (c) 2018, Download-Fritz. All rights reserved.<BR>
This program and the accompanying materials are licensed and made available
under the terms and conditions of the BSD License which accompanies this
distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php.
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include <Base.h>
#include <IndustryStandard/AppleMachoImage.h>
#include <Library/DebugLib.h>
#include <Library/MachoLib.h>
#include "MachoLibInternal.h"
/**
Returns whether the Relocation's type indicates a Pair for the Intel 64
platform.
@param[in] Type The Relocation's type to verify.
**/
BOOLEAN
MachoRelocationIsPairIntel64 (
IN UINT8 Type
)
{
return (Type == MachX8664RelocSubtractor);
}
/**
Returns whether the Relocation's type matches a Pair's for the Intel 64
platform.
@param[in] Type The Relocation's type to verify.
**/
BOOLEAN
MachoIsRelocationPairTypeIntel64 (
IN UINT8 Type
)
{
return (Type == MachX8664RelocUnsigned);
}
/**
Returns whether the Relocation shall be preserved for the Intel 64 platform.
@param[in] Type The Relocation's type to verify.
**/
BOOLEAN
MachoPreserveRelocationIntel64 (
IN UINT8 Type
)
{
return (Type == MachX8664RelocUnsigned);
}
/**
Retrieves an extern Relocation by the address it targets.
@param[in] Address The address to search for.
@retval NULL NULL is returned on failure.
**/
STATIC
MACH_RELOCATION_INFO *
InternalLookupRelocationByOffset (
IN UINT64 Address,
IN UINT32 NumRelocs,
IN MACH_RELOCATION_INFO *Relocs
)
{
UINT32 Index;
MACH_RELOCATION_INFO *Relocation;
for (Index = 0; Index < NumRelocs; ++Index) {
Relocation = &Relocs[Index];
//
// A section-based relocation entry can be skipped for absolute symbols.
//
if ((Relocation->Extern == 0)
&& (Relocation->SymbolNumber == MACH_RELOC_ABSOLUTE)) {
continue;
}
if ((UINT64)Relocation->Address == Address) {
return Relocation;
}
//
// Relocation Pairs can be skipped.
// Assumption: Intel X64. Currently verified by the Context
// initialization.
//
if (MachoRelocationIsPairIntel64 ((UINT8)Relocation->Type)) {
if (Index == (MAX_UINT32 - 1)) {
break;
}
++Index;
}
}
return NULL;
}
/**
Retrieves an extern Relocation by the address it targets.
@param[in,out] Context Context of the Mach-O.
@param[in] Address The address to search for.
@retval NULL NULL is returned on failure.
**/
MACH_RELOCATION_INFO *
InternalGetExternRelocationByOffset (
IN OUT OC_MACHO_CONTEXT *Context,
IN UINT64 Address
)
{
return InternalLookupRelocationByOffset (
Address,
Context->DySymtab->NumExternalRelocations,
Context->ExternRelocations
);
}
/**
Retrieves an extern Relocation by the address it targets.
@param[in,out] Context Context of the Mach-O.
@param[in] Address The address to search for.
@retval NULL NULL is returned on failure.
**/
MACH_RELOCATION_INFO *
InternalGetLocalRelocationByOffset (
IN OUT OC_MACHO_CONTEXT *Context,
IN UINT64 Address
)
{
return InternalLookupRelocationByOffset (
Address,
Context->DySymtab->NumOfLocalRelocations,
Context->LocalRelocations
);
}