reactos/ntoskrnl/ldr/rtl.c

   1 /* $Id$
   2  *
   3  * COPYRIGHT:       See COPYING in the top level directory
   4  * PROJECT:         ReactOS kernel
   5  * FILE:            ntoskrnl/ldr/rtl.c
   6  * PURPOSE:         Loader utilities
   7  *
   8  * PROGRAMMERS:     Jean Michault
   9  *                  Rex Jolliff (rex@lvcablemodem.com)
  10  */
  11
  12 /* INCLUDES *****************************************************************/
  13
  14 #include <ntoskrnl.h>
  15 #define NDEBUG
  16 #include <internal/debug.h>
  17
  18 /* FUNCTIONS ****************************************************************/
  19
  20 NTSTATUS STDCALL
  21 LdrGetProcedureAddress (IN PVOID BaseAddress,
  22                         IN PANSI_STRING Name,
  23                         IN ULONG Ordinal,
  24                         OUT PVOID *ProcedureAddress)
  25 {
  26    PIMAGE_EXPORT_DIRECTORY ExportDir;
  27    ULONG ExportDirSize = 0;
  28    PUSHORT OrdinalPtr;
  29    PULONG NamePtr;
  30    PCHAR CurrentNamePtr;
  31    PULONG AddressPtr;
  32
  33    if (ProcedureAddress == NULL)
  34       return STATUS_INVALID_PARAMETER;
  35
  36    /* get the pointer to the export directory */
  37    ExportDir = RtlImageDirectoryEntryToData(BaseAddress, TRUE,
  38                                             IMAGE_DIRECTORY_ENTRY_EXPORT,
  39                                             &ExportDirSize);
  40
  41    if (ExportDir == NULL || ExportDirSize == 0)
  42       return STATUS_INVALID_PARAMETER;
  43
  44    AddressPtr = (PULONG)RVA(BaseAddress, ExportDir->AddressOfFunctions);
  45
  46    if (Name && Name->Length)
  47    {
  48       LONG minn, maxn, mid, res;
  49
  50       /* Search for export by name */
  51
  52       /*
  53        * NOTE: Exports are always sorted and so we can apply binary search.
  54        * Also the function names are _case sensitive_, so respect that.
  55        * -- Filip Navara, August 1st, 2005
  56        */
  57
  58       OrdinalPtr = (PUSHORT)RVA(BaseAddress, ExportDir->AddressOfNameOrdinals);
  59       NamePtr = (PULONG)RVA(BaseAddress, ExportDir->AddressOfNames);
  60
  61       minn = 0; maxn = ExportDir->NumberOfNames - 1;
  62       while (minn <= maxn)
  63       {
  64          mid = (minn + maxn) / 2;
  65          CurrentNamePtr = (PCHAR)RVA(BaseAddress, NamePtr[mid]);
  66          res = strncmp(CurrentNamePtr, Name->Buffer, Name->Length);
  67          if (res == 0)
  68          {
  69             /*
  70              * Check if the beginning of the name matched, but it's still
  71              * not the whole name.
  72              */
  73             if (CurrentNamePtr[Name->Length] != 0)
  74             {
  75                res = -1;
  76             }
  77             else
  78             {
  79                *ProcedureAddress = (PVOID)RVA(BaseAddress, AddressPtr[OrdinalPtr[mid]]);
  80                return STATUS_SUCCESS;
  81             }
  82          }
  83          if (res > 0)
  84             maxn = mid - 1;
  85          else
  86             minn = mid + 1;
  87       }
  88
  89       CPRINT("LdrGetProcedureAddress: Can't resolve symbol '%Z'\n", Name);
  90    }
  91    else
  92    {
  93       /* Search for export by ordinal */
  94
  95       Ordinal &= 0x0000FFFF;
  96       if (Ordinal - ExportDir->Base < ExportDir->NumberOfFunctions)
  97       {
  98          *ProcedureAddress = (PVOID)RVA(BaseAddress, AddressPtr[Ordinal - ExportDir->Base]);
  99          return STATUS_SUCCESS;
 100       }
 101
 102       CPRINT("LdrGetProcedureAddress: Can't resolve symbol @%d\n", Ordinal);
 103    }
 104
 105    return STATUS_PROCEDURE_NOT_FOUND;
 106 }
 107
 108 /* EOF */