1 files changed, 115 insertions, 27 deletions

diff --git a/dlfcn.c b/dlfcn.c
index add1f4f..324fafc 100644
--- a/dlfcn.c
+++ b/dlfcn.c
@@ -22,7 +22,9 @@
 #include <stdlib.h>

 #include <crtdbg.h>

 #endif

+#define PSAPI_VERSION 1

 #include <windows.h>

+#include <psapi.h>

 #include <stdio.h>

 

 #define DLFCN_WIN32_EXPORTS

@@ -40,23 +42,25 @@ typedef struct global_object {
 } global_object;

 

 static global_object first_object;

+static global_object first_automatic_object;

+static int auto_ref_count = 0;

 

 /* These functions implement a double linked list for the global objects. */

-static global_object *global_search( HMODULE hModule )

+static global_object *global_search( global_object *start, HMODULE hModule )

 {

     global_object *pobject;

 

     if( hModule == NULL )

         return NULL;

 

-    for( pobject = &first_object; pobject ; pobject = pobject->next )

+    for( pobject = start; pobject; pobject = pobject->next )

         if( pobject->hModule == hModule )

             return pobject;

 

     return NULL;

 }

 

-static void global_add( HMODULE hModule )

+static void global_add( global_object *start, HMODULE hModule )

 {

     global_object *pobject;

     global_object *nobject;

@@ -64,15 +68,22 @@ static void global_add( HMODULE hModule )
     if( hModule == NULL )

         return;

 

-    pobject = global_search( hModule );

+    pobject = global_search( start, hModule );

 

     /* Do not add object again if it's already on the list */

     if( pobject )

         return;

 

-    for( pobject = &first_object; pobject->next ; pobject = pobject->next );

+    if( start == &first_automatic_object )

+    {

+        pobject = global_search( &first_object, hModule );

+        if( pobject )

+            return;

+    }

+

+    for( pobject = start; pobject->next; pobject = pobject->next );

 

-    nobject = malloc( sizeof(global_object) );

+    nobject = malloc( sizeof( global_object ) );

 

     /* Should this be enough to fail global_add, and therefore also fail

      * dlopen?

@@ -86,14 +97,14 @@ static void global_add( HMODULE hModule )
     nobject->hModule = hModule;

 }

 

-static void global_rem( HMODULE hModule )

+static void global_rem( global_object *start, HMODULE hModule )

 {

     global_object *pobject;

 

     if( hModule == NULL )

         return;

 

-    pobject = global_search( hModule );

+    pobject = global_search( start, hModule );

 

     if( !pobject )

         return;

@@ -185,18 +196,40 @@ void *dlopen( const char *file, int mode )
 

     if( file == 0 )

     {

+        HMODULE hAddtnlMods[1024]; // Already loaded modules

+        HANDLE hCurrentProc = GetCurrentProcess( );

+        DWORD cbNeeded;

+

         /* POSIX says that if the value of file is 0, a handle on a global

          * symbol object must be provided. That object must be able to access

          * all symbols from the original program file, and any objects loaded

          * with the RTLD_GLOBAL flag.

          * The return value from GetModuleHandle( ) allows us to retrieve

          * symbols only from the original program file. For objects loaded with

-         * the RTLD_GLOBAL flag, we create our own list later on.

+         * the RTLD_GLOBAL flag, we create our own list later on. For objects

+         * outside of the program file but already loaded (e.g. linked DLLs)

+         * they are added below.

          */

         hModule = GetModuleHandle( NULL );

 

         if( !hModule )

             save_err_ptr_str( file );

+

+

+        /* GetModuleHandle( NULL ) only returns the current program file. So

+         * if we want to get ALL loaded module including those in linked DLLs,

+         * we have to use EnumProcessModules( ).

+         */

+        if( EnumProcessModules( hCurrentProc, hAddtnlMods,

+                                sizeof( hAddtnlMods ), &cbNeeded ) != 0 )

+        {

+            DWORD i;

+            for( i = 0; i < cbNeeded / sizeof( HMODULE ); i++ )

+            {

+                global_add( &first_automatic_object, hAddtnlMods[i] );

+            }

+        }

+        auto_ref_count++;

     }

     else

     {

@@ -233,7 +266,7 @@ void *dlopen( const char *file, int mode )
         if( !hModule )

             save_err_str( lpFileName );

         else if( (mode & RTLD_GLOBAL) )

-            global_add( hModule );

+            global_add( &first_object, hModule );

     }

 

     /* Return to previous state of the error-mode bit flags. */

@@ -242,6 +275,21 @@ void *dlopen( const char *file, int mode )
     return (void *) hModule;

 }

 

+static void free_auto( )

+{

+    global_object *pobject = first_automatic_object.next;

+    if( pobject )

+    {

+        global_object *next;

+        for ( ; pobject; pobject = next )

+        {

+            next = pobject->next;

+            free( pobject );

+        }

+        first_automatic_object.next = NULL;

+    }

+}

+

 int dlclose( void *handle )

 {

     HMODULE hModule = (HMODULE) handle;

@@ -255,7 +303,18 @@ int dlclose( void *handle )
      * objects.

      */

     if( ret )

-        global_rem( hModule );

+    {

+        HMODULE cur = GetModuleHandle( NULL );

+        global_rem( &first_object, hModule );

+        if( hModule == cur )

+        {

+            auto_ref_count--;

+            if( auto_ref_count < 0 )

+                auto_ref_count = 0;

+            if( !auto_ref_count )

+                free_auto( );

+        }

+    }

     else

         save_err_ptr_str( handle );

 

@@ -268,37 +327,47 @@ int dlclose( void *handle )
 void *dlsym( void *handle, const char *name )

 {

     FARPROC symbol;

+    HMODULE hModule;

 

     current_error = NULL;

 

     symbol = GetProcAddress( handle, name );

 

-    if( symbol == NULL )

-    {

-        HMODULE hModule;

+    if( symbol != NULL )

+        goto end;

 

-        /* If the handle for the original program file is passed, also search

-         * in all globally loaded objects.

-         */

+    /* If the handle for the original program file is passed, also search

+     * in all globally loaded objects.

+     */

 

-        hModule = GetModuleHandle( NULL );

+    hModule = GetModuleHandle( NULL );

 

-        if( hModule == handle )

+    if( hModule == handle )

+    {

+        global_object *pobject;

+

+        for( pobject = &first_object; pobject; pobject = pobject->next )

         {

-            global_object *pobject;

+            if( pobject->hModule )

+            {

+                symbol = GetProcAddress( pobject->hModule, name );

+                if( symbol != NULL )

+                    goto end;

+            }

+        }

 

-            for( pobject = &first_object; pobject ; pobject = pobject->next )

+        for( pobject = &first_automatic_object; pobject; pobject = pobject->next )

+        {

+            if( pobject->hModule )

             {

-                if( pobject->hModule )

-                {

-                    symbol = GetProcAddress( pobject->hModule, name );

-                    if( symbol != NULL )

-                        break;

-                }

+                symbol = GetProcAddress( pobject->hModule, name );

+                if( symbol != NULL )

+                    goto end;

             }

         }

     }

 

+end:

     if( symbol == NULL )

         save_err_str( name );

 

@@ -316,3 +385,22 @@ char *dlerror( void )
 

     return error_pointer;

 }

+

+#ifdef SHARED

+BOOL WINAPI DllMain( HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved )

+{

+    /*

+     * https://msdn.microsoft.com/en-us/library/windows/desktop/ms682583(v=vs.85).aspx 

+     *

+     *     When handling DLL_PROCESS_DETACH, a DLL should free resources such as heap

+     *     memory only if the DLL is being unloaded dynamically (the lpReserved

+     *     parameter is NULL).

+     */

+    if( fdwReason == DLL_PROCESS_DETACH && !lpvReserved )

+    {

+        auto_ref_count = 0;

+        free_auto( );

+    }

+    return TRUE;

+}

+#endif