reactos/lib/rtl/image.c

   1 /* COPYRIGHT:       See COPYING in the top level directory
   2  * PROJECT:         ReactOS system libraries
   3  * FILE:            lib/rtl/image.c
   4  * PURPOSE:         Image handling functions
   5  * PROGRAMMER:      Eric Kohl
   6  */
   7
   8 /* INCLUDES *****************************************************************/
   9
  10 #include <rtl.h>
  11
  12 #define NDEBUG
  13 #include <debug.h>
  14
  15 /* FUNCTIONS *****************************************************************/
  16
  17 /*
  18  * @implemented
  19  */
  20 PIMAGE_NT_HEADERS NTAPI
  21 RtlImageNtHeader (IN PVOID BaseAddress)
  22 {
  23   PIMAGE_NT_HEADERS NtHeader;
  24   PIMAGE_DOS_HEADER DosHeader = (PIMAGE_DOS_HEADER)BaseAddress;
  25
  26   if (DosHeader && DosHeader->e_magic != IMAGE_DOS_SIGNATURE)
  27     {
  28       DPRINT1("DosHeader->e_magic %x\n", DosHeader->e_magic);
  29       DPRINT1("NtHeader 0x%p\n", ((ULONG_PTR)BaseAddress + DosHeader->e_lfanew));
  30     }
  31
  32   if (DosHeader && DosHeader->e_magic == IMAGE_DOS_SIGNATURE)
  33     {
  34       NtHeader = (PIMAGE_NT_HEADERS)((ULONG_PTR)BaseAddress + DosHeader->e_lfanew);
  35       if (NtHeader->Signature == IMAGE_NT_SIGNATURE)
  36         return NtHeader;
  37     }
  38
  39   return NULL;
  40 }
  41
  42
  43 /*
  44  * @implemented
  45  */
  46 PVOID
  47 NTAPI
  48 RtlImageDirectoryEntryToData (
  49         PVOID   BaseAddress,
  50         BOOLEAN bMappedAsImage,
  51         ULONG   Directory,
  52         PULONG  Size
  53         )
  54 {
  55         PIMAGE_NT_HEADERS NtHeader;
  56         ULONG Va;
  57
  58         /* Magic flag for non-mapped images. */
  59         if ((ULONG_PTR)BaseAddress & 1)
  60         {
  61                 BaseAddress = (PVOID)((ULONG_PTR)BaseAddress & ~1);
  62                 bMappedAsImage = FALSE;
  63         }
  64
  65
  66         NtHeader = RtlImageNtHeader (BaseAddress);
  67         if (NtHeader == NULL)
  68                 return NULL;
  69
  70         if (Directory >= NtHeader->OptionalHeader.NumberOfRvaAndSizes)
  71                 return NULL;
  72
  73         Va = NtHeader->OptionalHeader.DataDirectory[Directory].VirtualAddress;
  74         if (Va == 0)
  75                 return NULL;
  76
  77         *Size = NtHeader->OptionalHeader.DataDirectory[Directory].Size;
  78
  79         if (bMappedAsImage || Va < NtHeader->OptionalHeader.SizeOfHeaders)
  80                 return (PVOID)((ULONG_PTR)BaseAddress + Va);
  81
  82         /* image mapped as ordinary file, we must find raw pointer */
  83         return (PVOID)RtlImageRvaToVa (NtHeader, BaseAddress, Va, NULL);
  84 }
  85
  86
  87 /*
  88  * @implemented
  89  */
  90 PIMAGE_SECTION_HEADER
  91 NTAPI
  92 RtlImageRvaToSection (
  93         PIMAGE_NT_HEADERS       NtHeader,
  94         PVOID                   BaseAddress,
  95         ULONG                   Rva
  96         )
  97 {
  98         PIMAGE_SECTION_HEADER Section;
  99         ULONG Va;
 100         ULONG Count;
 101
 102         Count = NtHeader->FileHeader.NumberOfSections;
 103         Section = (PIMAGE_SECTION_HEADER)((ULONG)&NtHeader->OptionalHeader +
 104                                           NtHeader->FileHeader.SizeOfOptionalHeader);
 105         while (Count)
 106         {
 107                 Va = Section->VirtualAddress;
 108                 if ((Va <= Rva) &&
 109                     (Rva < Va + Section->SizeOfRawData))
 110                         return Section;
 111                 Section++;
 112         }
 113         return NULL;
 114 }
 115
 116
 117 /*
 118  * @implemented
 119  */
 120 ULONG
 121 NTAPI
 122 RtlImageRvaToVa (
 123         PIMAGE_NT_HEADERS       NtHeader,
 124         PVOID                   BaseAddress,
 125         ULONG                   Rva,
 126         PIMAGE_SECTION_HEADER   *SectionHeader
 127         )
 128 {
 129         PIMAGE_SECTION_HEADER Section = NULL;
 130
 131         if (SectionHeader)
 132                 Section = *SectionHeader;
 133
 134         if (Section == NULL ||
 135             Rva < Section->VirtualAddress ||
 136             Rva >= Section->VirtualAddress + Section->SizeOfRawData)
 137         {
 138                 Section = RtlImageRvaToSection (NtHeader, BaseAddress, Rva);
 139                 if (Section == NULL)
 140                         return 0;
 141
 142                 if (SectionHeader)
 143                         *SectionHeader = Section;
 144         }
 145
 146         return (ULONG)((ULONG_PTR)BaseAddress +
 147                        Rva +
 148                        Section->PointerToRawData -
 149                        (ULONG_PTR)Section->VirtualAddress);
 150 }
 151
 152 /* EOF */