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 #define RVA(m, b) ((ULONG)b + m)
  21
  22 NTSTATUS STDCALL
  23 LdrGetProcedureAddress (IN PVOID BaseAddress,
  24                         IN PANSI_STRING Name,
  25                         IN ULONG Ordinal,
  26                         OUT PVOID *ProcedureAddress)
  27 {
  28    PIMAGE_EXPORT_DIRECTORY ExportDir;
  29    PUSHORT OrdinalPtr;
  30    PULONG NamePtr;
  31    PULONG AddressPtr;
  32    ULONG i = 0;
  33
  34    /* get the pointer to the export directory */
  35    ExportDir = (PIMAGE_EXPORT_DIRECTORY)
  36         RtlImageDirectoryEntryToData (BaseAddress, TRUE,
  37                                       IMAGE_DIRECTORY_ENTRY_EXPORT, &i);
  38
  39    if (!ExportDir || !i || !ProcedureAddress)
  40      {
  41         return(STATUS_INVALID_PARAMETER);
  42      }
  43
  44    AddressPtr = (PULONG)RVA((char*)BaseAddress, ExportDir->AddressOfFunctions);
  45    if (Name && Name->Length)
  46      {
  47        LONG minn, maxn;
  48
  49         /* by name */
  50        OrdinalPtr =
  51          (PUSHORT)RVA((char*)BaseAddress, ExportDir->AddressOfNameOrdinals);
  52        NamePtr = (PULONG)RVA((char*)BaseAddress, ExportDir->AddressOfNames);
  53
  54         minn = 0; maxn = ExportDir->NumberOfNames;
  55         while (minn <= maxn)
  56           {
  57             LONG mid;
  58             LONG res;
  59
  60             mid = (minn + maxn) / 2;
  61             res = _strnicmp(Name->Buffer, (PCH)RVA((char*)BaseAddress, NamePtr[mid]),
  62                             Name->Length);
  63             if (res == 0)
  64               {
  65                 *ProcedureAddress =
  66                   (PVOID)RVA((char*)BaseAddress, AddressPtr[OrdinalPtr[mid]]);
  67                 return(STATUS_SUCCESS);
  68               }
  69             else if (res > 0)
  70               {
  71                 maxn = mid - 1;
  72               }
  73             else
  74               {
  75                 minn = mid + 1;
  76               }
  77           }
  78
  79         for (i = 0; i < ExportDir->NumberOfNames; i++, NamePtr++, OrdinalPtr++)
  80           {
  81              if (!_strnicmp(Name->Buffer,
  82                             (char*)((char*)BaseAddress + *NamePtr), Name->Length))
  83                {
  84                   *ProcedureAddress =
  85                     (PVOID)((ULONG)BaseAddress +
  86                             (ULONG)AddressPtr[*OrdinalPtr]);
  87                   return STATUS_SUCCESS;
  88                }
  89           }
  90         CPRINT("LdrGetProcedureAddress: Can't resolve symbol '%Z'\n", Name);
  91      }
  92    else
  93      {
  94         /* by ordinal */
  95         Ordinal &= 0x0000FFFF;
  96         if (Ordinal - ExportDir->Base < ExportDir->NumberOfFunctions)
  97           {
  98              *ProcedureAddress =
  99                (PVOID)((ULONG)BaseAddress +
 100                        (ULONG)AddressPtr[Ordinal - ExportDir->Base]);
 101              return STATUS_SUCCESS;
 102           }
 103         CPRINT("LdrGetProcedureAddress: Can't resolve symbol @%d\n",
 104                  Ordinal);
 105   }
 106
 107    return STATUS_PROCEDURE_NOT_FOUND;
 108 }
 109
 110 /* EOF */