123 lines
2.4 KiB
C
123 lines
2.4 KiB
C
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/*++
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Copyright (c) 1990 Microsoft Corporation
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Module Name:
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MEMORY.C
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Abstract:
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This file contains the routines that deal with memory management.
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Author:
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Rajen Shah (rajens) 12-Jul-1991
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[Environment:]
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User Mode - Win32, except for NTSTATUS returned by some functions.
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Revision History:
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--*/
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// INCLUDES
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#include <eventp.h>
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// Implement my own tail-checking, since the system code requires a
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// debugging build
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//#define TAIL_CHECKING
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#ifdef TAIL_CHECKING
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#define CHECK_HEAP_TAIL_SIZE 16
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#define CHECK_HEAP_TAIL_FILL 0xAB
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#endif
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PVOID ElfpAllocateBuffer(ULONG Size)
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/*++
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Routine Description:
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Allocate a buffer of the given size, and return the pointer in BufPtr.
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Return Value:
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Pointer to allocated buffer (or NULL).
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--*/
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{
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PVOID BufPtr;
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#ifdef TAIL_CHECKING
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// Keep the offset of the pattern (so we don't have to have internal
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// knowledge about the granularity of the heap block) and copy a
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// known pattern after the end of the user's block
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BufPtr = (PVOID*)MIDL_user_allocate(Size
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+ CHECK_HEAP_TAIL_SIZE + sizeof(DWORD));
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*((PDWORD)BufPtr) = Size + sizeof(DWORD);
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(PBYTE)BufPtr += sizeof(DWORD);
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RtlFillMemory((PBYTE)BufPtr + Size,
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CHECK_HEAP_TAIL_SIZE,
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CHECK_HEAP_TAIL_FILL);
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#else
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BufPtr = (PVOID*)MIDL_user_allocate(Size);
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#endif
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return (BufPtr);
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}
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VOID ElfpFreeBuffer(PVOID BufPtr)
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/*++
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Routine Description:
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Frees a buffer previously allocated by AllocateBuffer.
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Arguments:
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Pointer to buffer.
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Return Value:
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NOTHING
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--*/
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{
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#ifdef TAIL_CHECKING
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// Check for NULL when TAIL_CHECKING is enabled since
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// it allows us to avoid checking every pointer that
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// we want to free vs. NULL when we call ElfpFreeBuffer.
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// Note that MIDL_user_free handles NULL.
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if (BufPtr != NULL) {
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DWORD i;
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PBYTE pb;
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// Back up to real start of block
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(PBYTE)BufPtr -= sizeof(DWORD);
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i = *((PDWORD)BufPtr);
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pb = (PBYTE)BufPtr + i;
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for (i = 0; i < CHECK_HEAP_TAIL_SIZE; i++, pb++) {
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if (*pb != CHECK_HEAP_TAIL_FILL) {
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ElfDbgPrint(("[ELF] Heap has been corrupted at 0x%x\n",
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BufPtr));
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// Make it access violate
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pb = (PBYTE)0;
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*pb = 1;
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}
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}
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}
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#endif
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MIDL_user_free(BufPtr);
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return;
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}
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