sdk/lib/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 <stdarg.h>
   9 #include <windef.h>
  10 #include <winbase.h>
  11 #include <string.h>
  12
  13 #if defined (_WIN64) && defined (__ia64__)
  14 #error FIXME: Unsupported __ImageBase implementation.
  15 #else
  16 #ifdef __GNUC__
  17 /* Hack, for bug in ld.  Will be removed soon.  */
  18 #define __ImageBase __MINGW_LSYMBOL(_image_base__)
  19 #endif
  20 /* This symbol is defined by the linker.  */
  21 extern IMAGE_DOS_HEADER __ImageBase;
  22 #endif
  23
  24 WINBOOL _ValidateImageBase (PBYTE);
  25
  26 WINBOOL
  27 _ValidateImageBase (PBYTE pImageBase)
  28 {
  29   PIMAGE_DOS_HEADER pDOSHeader;
  30   PIMAGE_NT_HEADERS pNTHeader;
  31   PIMAGE_OPTIONAL_HEADER pOptHeader;
  32
  33   pDOSHeader = (PIMAGE_DOS_HEADER) pImageBase;
  34   if (pDOSHeader->e_magic != IMAGE_DOS_SIGNATURE)
  35     return FALSE;
  36   pNTHeader = (PIMAGE_NT_HEADERS) ((PBYTE) pDOSHeader + pDOSHeader->e_lfanew);
  37   if (pNTHeader->Signature != IMAGE_NT_SIGNATURE)
  38     return FALSE;
  39   pOptHeader = (PIMAGE_OPTIONAL_HEADER) &pNTHeader->OptionalHeader;
  40   if (pOptHeader->Magic != IMAGE_NT_OPTIONAL_HDR_MAGIC)
  41     return FALSE;
  42   return TRUE;
  43 }
  44
  45 PIMAGE_SECTION_HEADER _FindPESection (PBYTE, DWORD_PTR);
  46
  47 PIMAGE_SECTION_HEADER
  48 _FindPESection (PBYTE pImageBase, DWORD_PTR rva)
  49 {
  50   PIMAGE_NT_HEADERS pNTHeader;
  51   PIMAGE_SECTION_HEADER pSection;
  52   unsigned int iSection;
  53
  54   pNTHeader = (PIMAGE_NT_HEADERS) (pImageBase + ((PIMAGE_DOS_HEADER) pImageBase)->e_lfanew);
  55
  56   for (iSection = 0, pSection = IMAGE_FIRST_SECTION (pNTHeader);
  57     iSection < pNTHeader->FileHeader.NumberOfSections;
  58     ++iSection,++pSection)
  59     {
  60       if (rva >= pSection->VirtualAddress
  61           && rva < pSection->VirtualAddress + pSection->Misc.VirtualSize)
  62         return pSection;
  63     }
  64   return NULL;
  65 }
  66
  67 PIMAGE_SECTION_HEADER _FindPESectionByName (const char *);
  68
  69 PIMAGE_SECTION_HEADER
  70 _FindPESectionByName (const char *pName)
  71 {
  72   PBYTE pImageBase;
  73   PIMAGE_NT_HEADERS pNTHeader;
  74   PIMAGE_SECTION_HEADER pSection;
  75   unsigned int iSection;
  76
  77   /* Long names aren't supported.  */
  78   if (strlen (pName) > IMAGE_SIZEOF_SHORT_NAME)
  79     return NULL;
  80
  81   pImageBase = (PBYTE) &__ImageBase;
  82   if (! _ValidateImageBase (pImageBase))
  83     return NULL;
  84
  85   pNTHeader = (PIMAGE_NT_HEADERS) (pImageBase + ((PIMAGE_DOS_HEADER) pImageBase)->e_lfanew);
  86
  87   for (iSection = 0, pSection = IMAGE_FIRST_SECTION (pNTHeader);
  88     iSection < pNTHeader->FileHeader.NumberOfSections;
  89     ++iSection,++pSection)
  90     {
  91       if (!strncmp ((char *) &pSection->Name[0], pName, IMAGE_SIZEOF_SHORT_NAME))
  92         return pSection;
  93     }
  94   return NULL;
  95 }
  96
  97 int __mingw_GetSectionCount (void);
  98 PIMAGE_SECTION_HEADER __mingw_GetSectionForAddress (LPVOID p);
  99
 100 PIMAGE_SECTION_HEADER
 101 __mingw_GetSectionForAddress (LPVOID p)
 102 {
 103   PBYTE pImageBase;
 104   DWORD_PTR rva;
 105
 106   pImageBase = (PBYTE) &__ImageBase;
 107   if (! _ValidateImageBase (pImageBase))
 108     return NULL;
 109
 110   rva = (DWORD_PTR) (((PBYTE) p) - pImageBase);
 111   return _FindPESection (pImageBase, rva);
 112 }
 113
 114 int
 115 __mingw_GetSectionCount (void)
 116 {
 117   PBYTE pImageBase;
 118   PIMAGE_NT_HEADERS pNTHeader;
 119
 120   pImageBase = (PBYTE) &__ImageBase;
 121   if (! _ValidateImageBase (pImageBase))
 122     return 0;
 123
 124   pNTHeader = (PIMAGE_NT_HEADERS) (pImageBase + ((PIMAGE_DOS_HEADER) pImageBase)->e_lfanew);
 125
 126   return (int) pNTHeader->FileHeader.NumberOfSections;
 127 }
 128
 129
 130 PIMAGE_SECTION_HEADER _FindPESectionExec (size_t);
 131
 132 PIMAGE_SECTION_HEADER
 133 _FindPESectionExec (size_t eNo)
 134 {
 135   PBYTE pImageBase;
 136   PIMAGE_NT_HEADERS pNTHeader;
 137   PIMAGE_SECTION_HEADER pSection;
 138   unsigned int iSection;
 139
 140   pImageBase = (PBYTE) &__ImageBase;
 141   if (! _ValidateImageBase (pImageBase))
 142     return NULL;
 143
 144   pNTHeader = (PIMAGE_NT_HEADERS) (pImageBase + ((PIMAGE_DOS_HEADER) pImageBase)->e_lfanew);
 145
 146   for (iSection = 0, pSection = IMAGE_FIRST_SECTION (pNTHeader);
 147     iSection < pNTHeader->FileHeader.NumberOfSections;
 148     ++iSection,++pSection)
 149     {
 150       if ((pSection->Characteristics & IMAGE_SCN_MEM_EXECUTE) != 0)
 151       {
 152         if (!eNo)
 153           return pSection;
 154         --eNo;
 155       }
 156     }
 157   return NULL;
 158 }
 159
 160 PBYTE _GetPEImageBase (void);
 161
 162 PBYTE
 163 _GetPEImageBase (void)
 164 {
 165   PBYTE pImageBase;
 166   pImageBase = (PBYTE) &__ImageBase;
 167   if (! _ValidateImageBase (pImageBase))
 168     return NULL;
 169   return pImageBase;
 170 }
 171
 172 WINBOOL _IsNonwritableInCurrentImage (PBYTE);
 173
 174 WINBOOL
 175 _IsNonwritableInCurrentImage (PBYTE pTarget)
 176 {
 177   PBYTE pImageBase;
 178   DWORD_PTR rvaTarget;
 179   PIMAGE_SECTION_HEADER pSection;
 180
 181   pImageBase = (PBYTE) &__ImageBase;
 182   if (! _ValidateImageBase (pImageBase))
 183     return FALSE;
 184   rvaTarget = pTarget - pImageBase;
 185   pSection = _FindPESection (pImageBase, rvaTarget);
 186   if (pSection == NULL)
 187     return FALSE;
 188   return (pSection->Characteristics & IMAGE_SCN_MEM_WRITE) == 0;
 189 }
 190
 191 const char *
 192 __mingw_enum_import_library_names (int);
 193
 194 const char *
 195 __mingw_enum_import_library_names (int i)
 196 {
 197   PBYTE pImageBase;
 198   PIMAGE_NT_HEADERS pNTHeader;
 199   PIMAGE_IMPORT_DESCRIPTOR importDesc;
 200   PIMAGE_SECTION_HEADER pSection;
 201   DWORD importsStartRVA;
 202
 203   pImageBase = (PBYTE) &__ImageBase;
 204   if (! _ValidateImageBase (pImageBase))
 205     return NULL;
 206
 207   pNTHeader = (PIMAGE_NT_HEADERS) (pImageBase + ((PIMAGE_DOS_HEADER) pImageBase)->e_lfanew);
 208
 209   importsStartRVA = pNTHeader->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress;
 210   if (!importsStartRVA)
 211     return NULL;
 212
 213   pSection = _FindPESection (pImageBase, importsStartRVA);
 214   if (!pSection)
 215       return NULL;
 216
 217   importDesc = (PIMAGE_IMPORT_DESCRIPTOR) (pImageBase + importsStartRVA);
 218   if (!importDesc)
 219     return NULL;
 220
 221   for (;;)
 222     {
 223       if (importDesc->TimeDateStamp == 0 && importDesc->Name == 0)
 224         break;
 225
 226       if (i <= 0)
 227        return (char *) (pImageBase + importDesc->Name);
 228       --i;
 229       importDesc++;
 230     }
 231
 232   return NULL;
 233 }
 234
 235 HMODULE __mingw_get_msvcrt_handle(void);
 236 HMODULE __mingw_get_msvcrt_handle(void)
 237 {
 238     static HANDLE msvcrt_handle;
 239
 240     if(!msvcrt_handle) {
 241         const char *lib_name;
 242         int i = 0;
 243
 244         while ((lib_name = __mingw_enum_import_library_names (i++))) {
 245             if((lib_name[0] == 'm' || lib_name[0] == 'M')
 246                && (lib_name[1] == 's' || lib_name[1] == 'S')
 247                && (lib_name[2] == 'v' || lib_name[2] == 'V')
 248                && (lib_name[3] == 'c' || lib_name[3] == 'C')
 249                && (lib_name[4] == 'r' || lib_name[4] == 'R')
 250                && (lib_name[5] == 't' || lib_name[5] == 'T' || ('0' <= lib_name[5] && lib_name[5] <= '9')))
 251                 break;
 252         }
 253
 254        if(lib_name)
 255             msvcrt_handle = GetModuleHandleA(lib_name);
 256         if(!msvcrt_handle)
 257             msvcrt_handle = LoadLibraryW(L"msvcrt.dll");
 258     }
 259
 260     return msvcrt_handle;
 261 }