1 files changed, 57 insertions, 7 deletions

diff --git a/src/dlfcn.c b/src/dlfcn.c
index 4e4e10e..80bd119 100644
--- a/src/dlfcn.c
+++ b/src/dlfcn.c
@@ -24,9 +24,6 @@
  * THE SOFTWARE.

  */

 

-#ifndef _WIN32_WINNT

-#define _WIN32_WINNT 0x0501

-#endif

 #ifdef _DEBUG

 #define _CRTDBG_MAP_ALLOC

 #include <stdlib.h>

@@ -36,6 +33,14 @@
 #include <stdio.h>

 #include <stdlib.h>

 

+/* Older SDK versions do not have these macros */

+#ifndef GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS

+#define GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS 0x4

+#endif

+#ifndef GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT

+#define GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT 0x2

+#endif

+

 #ifdef _MSC_VER

 /* https://docs.microsoft.com/en-us/cpp/intrinsics/returnaddress */

 #pragma intrinsic( _ReturnAddress )

@@ -196,6 +201,44 @@ static void save_err_ptr_str( const void *ptr, DWORD dwMessageId )
     save_err_str( ptr_buf, dwMessageId );

 }

 

+static HMODULE MyGetModuleHandleFromAddress( void *addr )

+{

+    static BOOL (WINAPI *GetModuleHandleExAPtr)(DWORD, LPCSTR, HMODULE *) = NULL;

+    static BOOL failed = FALSE;

+    HMODULE kernel32;

+    HMODULE hModule;

+    MEMORY_BASIC_INFORMATION info;

+    SIZE_T sLen;

+

+    if( !failed && GetModuleHandleExAPtr == NULL )

+    {

+        kernel32 = GetModuleHandleA( "Kernel32.dll" );

+        if( kernel32 != NULL )

+            GetModuleHandleExAPtr = (BOOL (WINAPI *)(DWORD, LPCSTR, HMODULE *)) GetProcAddress( kernel32, "GetModuleHandleExA" );

+        if( GetModuleHandleExAPtr == NULL )

+            failed = TRUE;

+    }

+

+    if( !failed )

+    {

+        /* If GetModuleHandleExA is available use it with GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS */

+        if( !GetModuleHandleExAPtr( GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT, (LPCSTR) addr, &hModule ) )

+            return NULL;

+    }

+    else

+    {

+        /* To get HMODULE from address use undocumented hack from https://stackoverflow.com/a/2396380

+         * The HMODULE of a DLL is the same value as the module's base address.

+         */

+        sLen = VirtualQuery( addr, &info, sizeof( info ) );

+        if( sLen != sizeof( info ) )

+            return NULL;

+        hModule = (HMODULE) info.AllocationBase;

+    }

+

+    return hModule;

+}

+

 /* Load Psapi.dll at runtime, this avoids linking caveat */

 static BOOL MyEnumProcessModules( HANDLE hProcess, HMODULE *lphModule, DWORD cb, LPDWORD lpcbNeeded )

 {

@@ -402,9 +445,12 @@ void *dlsym( void *handle, const char *name )
          * The next object is the one found upon the application of a load

          * order symbol resolution algorithm. To get caller function of dlsym()

          * use _ReturnAddress() intrinsic. To get HMODULE of caller function

-         * use standard GetModuleHandleExA() function.

+         * use MyGetModuleHandleFromAddress() which calls either standard

+         * GetModuleHandleExA() function or hack via VirtualQuery().

          */

-        if( !GetModuleHandleExA( GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT, (LPCSTR) _ReturnAddress( ), &hCaller ) )

+        hCaller = MyGetModuleHandleFromAddress( _ReturnAddress( ) );

+

+        if( hCaller == NULL )

         {

             dwMessageId = ERROR_INVALID_PARAMETER;

             goto end;

@@ -638,7 +684,9 @@ static BOOL fill_info( void *addr, Dl_info *info )
     void *funcAddress = NULL;

 

     /* Get module of the specified address */

-    if( !GetModuleHandleExA( GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT, addr, &hModule ) || hModule == NULL )

+    hModule = MyGetModuleHandleFromAddress( addr );

+

+    if( hModule == NULL )

         return FALSE;

 

     dwSize = GetModuleFileNameA( hModule, module_filename, sizeof( module_filename ) );

@@ -676,7 +724,9 @@ int dladdr( void *addr, Dl_info *info )
         HMODULE hModule;

 

         /* Get module of the import thunk address */

-        if( !GetModuleHandleExA( GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT, addr, &hModule ) || hModule == NULL )

+        hModule = MyGetModuleHandleFromAddress( addr );

+

+        if( hModule == NULL )

             return 0;

 

         if( !get_image_section( hModule, IMAGE_DIRECTORY_ENTRY_IAT, &iat, &iatSize ) )