sdk/lib/rtl/heapuser.c

   1 /*
   2  * COPYRIGHT:       See COPYING in the top level directory
   3  * PROJECT:         ReactOS system libraries
   4  * FILE:            lib/rtl/heapuser.c
   5  * PURPOSE:         RTL Heap backend allocator (user mode only functions)
   6  * PROGRAMMERS:     Copyright 2010 Aleksey Bragin
   7  */
   8
   9 /* INCLUDES *****************************************************************/
  10
  11 #include <rtl.h>
  12 #include <heap.h>
  13
  14 #define NDEBUG
  15 #include <debug.h>
  16
  17 RTL_CRITICAL_SECTION RtlpProcessHeapsListLock;
  18
  19
  20 /* Usermode only! */
  21 VOID
  22 NTAPI
  23 RtlpAddHeapToProcessList(PHEAP Heap)
  24 {
  25     PPEB Peb;
  26
  27     /* Get PEB */
  28     Peb = RtlGetCurrentPeb();
  29
  30     /* Acquire the lock */
  31     RtlEnterCriticalSection(&RtlpProcessHeapsListLock);
  32
  33     //_SEH2_TRY {
  34     /* Check if max number of heaps reached */
  35     if (Peb->NumberOfHeaps == Peb->MaximumNumberOfHeaps)
  36     {
  37         // TODO: Handle this case
  38         ASSERT(FALSE);
  39     }
  40
  41     /* Add the heap to the process heaps */
  42     Peb->ProcessHeaps[Peb->NumberOfHeaps] = Heap;
  43     Peb->NumberOfHeaps++;
  44     Heap->ProcessHeapsListIndex = (USHORT)Peb->NumberOfHeaps;
  45     // } _SEH2_FINALLY {
  46
  47     /* Release the lock */
  48     RtlLeaveCriticalSection(&RtlpProcessHeapsListLock);
  49
  50     // } _SEH2_END
  51 }
  52
  53 /* Usermode only! */
  54 VOID
  55 NTAPI
  56 RtlpRemoveHeapFromProcessList(PHEAP Heap)
  57 {
  58     PPEB Peb;
  59     PHEAP *Current, *Next;
  60     ULONG Count;
  61
  62     /* Get PEB */
  63     Peb = RtlGetCurrentPeb();
  64
  65     /* Acquire the lock */
  66     RtlEnterCriticalSection(&RtlpProcessHeapsListLock);
  67
  68     /* Check if we don't need anything to do */
  69     if ((Heap->ProcessHeapsListIndex == 0) ||
  70         (Heap->ProcessHeapsListIndex > Peb->NumberOfHeaps) ||
  71         (Peb->NumberOfHeaps == 0))
  72     {
  73         /* Release the lock */
  74         RtlLeaveCriticalSection(&RtlpProcessHeapsListLock);
  75
  76         return;
  77     }
  78
  79     /* The process actually has more than one heap.
  80        Use classic, lernt from university times algorithm for removing an entry
  81        from a static array */
  82
  83     Current = (PHEAP *)&Peb->ProcessHeaps[Heap->ProcessHeapsListIndex - 1];
  84     Next = Current + 1;
  85
  86     /* How many items we need to shift to the left */
  87     Count = Peb->NumberOfHeaps - (Heap->ProcessHeapsListIndex - 1);
  88
  89     /* Move them all in a loop */
  90     while (--Count)
  91     {
  92         /* Copy it and advance next pointer */
  93         *Current = *Next;
  94
  95         /* Update its index */
  96         (*Current)->ProcessHeapsListIndex -= 1;
  97
  98         /* Advance pointers */
  99         Current++;
 100         Next++;
 101     }
 102
 103     /* Decrease total number of heaps */
 104     Peb->NumberOfHeaps--;
 105
 106     /* Zero last unused item */
 107     Peb->ProcessHeaps[Peb->NumberOfHeaps] = NULL;
 108     Heap->ProcessHeapsListIndex = 0;
 109
 110     /* Release the lock */
 111     RtlLeaveCriticalSection(&RtlpProcessHeapsListLock);
 112 }
 113
 114 VOID
 115 NTAPI
 116 RtlInitializeHeapManager(VOID)
 117 {
 118     PPEB Peb;
 119
 120     /* Get PEB */
 121     Peb = RtlGetCurrentPeb();
 122
 123     /* Initialize heap-related fields of PEB */
 124     Peb->NumberOfHeaps = 0;
 125
 126     /* Initialize the process heaps list protecting lock */
 127     RtlInitializeCriticalSection(&RtlpProcessHeapsListLock);
 128 }
 129