lib/rtl/heapuser.c

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