reactos/lib/sdk/crt/startup/pesect.c

   1 /**
   2  * This file has no copyright assigned and is placed in the Public Domain.
   3  * This file is part of the w64 mingw-runtime package.
   4  * No warranty is given; refer to the file DISCLAIMER.PD within this package.
   5  */
   6
   7 #include <windows.h>
   8 #include <string.h>
   9
  10 #if defined (_WIN64) && defined (__ia64__)
  11 #error FIXME: Unsupported __ImageBase implementation.
  12 #else
  13 /* Hack, for bug in ld.  Will be removed soon.  */
  14 #ifndef _MSC_VER
  15 #define __ImageBase __MINGW_LSYMBOL(_image_base__)
  16 #endif
  17 /* This symbol is defined by the linker.  */
  18 extern IMAGE_DOS_HEADER __ImageBase;
  19 #endif
  20
  21 WINBOOL _ValidateImageBase (PBYTE);
  22
  23 WINBOOL
  24 _ValidateImageBase (PBYTE pImageBase)
  25 {
  26   PIMAGE_DOS_HEADER pDOSHeader;
  27   PIMAGE_NT_HEADERS pNTHeader;
  28   PIMAGE_OPTIONAL_HEADER pOptHeader;
  29
  30   pDOSHeader = (PIMAGE_DOS_HEADER) pImageBase;
  31   if (pDOSHeader->e_magic != IMAGE_DOS_SIGNATURE)
  32     return FALSE;
  33   pNTHeader = (PIMAGE_NT_HEADERS) ((PBYTE) pDOSHeader + pDOSHeader->e_lfanew);
  34   if (pNTHeader->Signature != IMAGE_NT_SIGNATURE)
  35     return FALSE;
  36   pOptHeader = (PIMAGE_OPTIONAL_HEADER) &pNTHeader->OptionalHeader;
  37   if (pOptHeader->Magic != IMAGE_NT_OPTIONAL_HDR_MAGIC)
  38     return FALSE;
  39   return TRUE;
  40 }
  41
  42 PIMAGE_SECTION_HEADER _FindPESection (PBYTE, DWORD_PTR);
  43
  44 PIMAGE_SECTION_HEADER
  45 _FindPESection (PBYTE pImageBase, DWORD_PTR rva)
  46 {
  47   PIMAGE_NT_HEADERS pNTHeader;
  48   PIMAGE_SECTION_HEADER pSection;
  49   unsigned int iSection;
  50
  51   pNTHeader = (PIMAGE_NT_HEADERS) (pImageBase + ((PIMAGE_DOS_HEADER) pImageBase)->e_lfanew);
  52
  53   for (iSection = 0, pSection = IMAGE_FIRST_SECTION (pNTHeader);
  54     iSection < pNTHeader->FileHeader.NumberOfSections;
  55     ++iSection,++pSection)
  56     {
  57       if (rva >= pSection->VirtualAddress
  58           && rva < pSection->VirtualAddress + pSection->Misc.VirtualSize)
  59         return pSection;
  60     }
  61   return NULL;
  62 }
  63
  64 PIMAGE_SECTION_HEADER _FindPESectionByName (const char *);
  65
  66 PIMAGE_SECTION_HEADER
  67 _FindPESectionByName (const char *pName)
  68 {
  69   PBYTE pImageBase;
  70   PIMAGE_NT_HEADERS pNTHeader;
  71   PIMAGE_SECTION_HEADER pSection;
  72   unsigned int iSection;
  73
  74   /* Long names aren't supported.  */
  75   if (strlen (pName) > IMAGE_SIZEOF_SHORT_NAME)
  76     return NULL;
  77
  78   pImageBase = (PBYTE) &__ImageBase;
  79   if (! _ValidateImageBase (pImageBase))
  80     return NULL;
  81
  82   pNTHeader = (PIMAGE_NT_HEADERS) (pImageBase + ((PIMAGE_DOS_HEADER) pImageBase)->e_lfanew);
  83
  84   for (iSection = 0, pSection = IMAGE_FIRST_SECTION (pNTHeader);
  85     iSection < pNTHeader->FileHeader.NumberOfSections;
  86     ++iSection,++pSection)
  87     {
  88       if (!strncmp ((char *) &pSection->Name[0], pName, IMAGE_SIZEOF_SHORT_NAME))
  89         return pSection;
  90     }
  91   return NULL;
  92 }
  93
  94 int __mingw_GetSectionCount (void);
  95 PIMAGE_SECTION_HEADER __mingw_GetSectionForAddress (LPVOID p);
  96
  97 PIMAGE_SECTION_HEADER
  98 __mingw_GetSectionForAddress (LPVOID p)
  99 {
 100   PBYTE pImageBase;
 101   DWORD_PTR rva;
 102
 103   pImageBase = (PBYTE) &__ImageBase;
 104   if (! _ValidateImageBase (pImageBase))
 105     return NULL;
 106
 107   rva = (DWORD_PTR) (((PBYTE) p) - pImageBase);
 108   return _FindPESection (pImageBase, rva);
 109 }
 110
 111 int
 112 __mingw_GetSectionCount (void)
 113 {
 114   PBYTE pImageBase;
 115   PIMAGE_NT_HEADERS pNTHeader;
 116
 117   pImageBase = (PBYTE) &__ImageBase;
 118   if (! _ValidateImageBase (pImageBase))
 119     return 0;
 120
 121   pNTHeader = (PIMAGE_NT_HEADERS) (pImageBase + ((PIMAGE_DOS_HEADER) pImageBase)->e_lfanew);
 122
 123   return (int) pNTHeader->FileHeader.NumberOfSections;
 124 }
 125
 126
 127 PIMAGE_SECTION_HEADER _FindPESectionExec (size_t);
 128
 129 PIMAGE_SECTION_HEADER
 130 _FindPESectionExec (size_t eNo)
 131 {
 132   PBYTE pImageBase;
 133   PIMAGE_NT_HEADERS pNTHeader;
 134   PIMAGE_SECTION_HEADER pSection;
 135   unsigned int iSection;
 136
 137   pImageBase = (PBYTE) &__ImageBase;
 138   if (! _ValidateImageBase (pImageBase))
 139     return NULL;
 140
 141   pNTHeader = (PIMAGE_NT_HEADERS) (pImageBase + ((PIMAGE_DOS_HEADER) pImageBase)->e_lfanew);
 142
 143   for (iSection = 0, pSection = IMAGE_FIRST_SECTION (pNTHeader);
 144     iSection < pNTHeader->FileHeader.NumberOfSections;
 145     ++iSection,++pSection)
 146     {
 147       if ((pSection->Characteristics & IMAGE_SCN_MEM_EXECUTE) != 0)
 148       {
 149         if (!eNo)
 150           return pSection;
 151         --eNo;
 152       }
 153     }
 154   return NULL;
 155 }
 156
 157 PBYTE _GetPEImageBase (void);
 158
 159 PBYTE
 160 _GetPEImageBase (void)
 161 {
 162   PBYTE pImageBase;
 163   pImageBase = (PBYTE) &__ImageBase;
 164   if (! _ValidateImageBase (pImageBase))
 165     return NULL;
 166   return pImageBase;
 167 }
 168
 169 WINBOOL _IsNonwritableInCurrentImage (PBYTE);
 170
 171 WINBOOL
 172 _IsNonwritableInCurrentImage (PBYTE pTarget)
 173 {
 174   PBYTE pImageBase;
 175   DWORD_PTR rvaTarget;
 176   PIMAGE_SECTION_HEADER pSection;
 177
 178   pImageBase = (PBYTE) &__ImageBase;
 179   if (! _ValidateImageBase (pImageBase))
 180     return FALSE;
 181   rvaTarget = pTarget - pImageBase;
 182   pSection = _FindPESection (pImageBase, rvaTarget);
 183   if (pSection == NULL)
 184     return FALSE;
 185   return (pSection->Characteristics & IMAGE_SCN_MEM_WRITE) == 0;
 186 }