fdo#86745 - Possible exception/segfault in jurt jpipe.dll under Windows ...

- Remove the LoadLibrary from DLLMain (from windows not recommended)
   see http://msdn.microsoft.com/en-us/library/windows/desktop/ms682583(v=vs.85).aspx
   in section Remarks
- Improve the comment why we need two dll's (jpipe.dll and jpipx.dll)
- Integrate CriticalSection, init in DllMain see link
   http://msdn.microsoft.com/en-us/library/windows/desktop/dn633971(v=vs.85).aspx#general_best_practices

Signed-off-by: Stephan Bergmann <sbergman@redhat.com>: removed the unsafe module
== NULL check around the critical section in getFunction

Change-Id: I6d5f655a4942437f6dc722236f6c371063e2c407

jurt/source/pipe/com_sun_star_lib_connections_pipe_PipeConnection.c

@@ -21,15 +21,15 @@
 #include "osl/security.h"
 #include <osl/pipe.h>
 
-/* On Windows, jpipe.dll must not have dependencies on any other URE DLLs, as
-   Java System.LoadLibrary could otherwise not load it.  Therefore, on Windows,
-   this code goes into a jpipx.dll that the jpipe.dll wrapper loads with
-   LoadLibraryEx(LOAD_WITH_ALTERED_SEARCH_PATH).  The function names in this
-   wrapped code are truncated from the long JNICALL names, as JNICALL causes
-   some "@N" with different numeric values for N (and probably different across
-   32 and 64 bit) to be added to the symbol names, which the calls to
-   GetProcAddress in wrapper/wrapper.c would otheriwse have to take into
-   account.
+/* On Windows, jpipe.dll must not have static dependencies on any other URE DLLs
+   (sal3.dll, uwinapi.dll), as Java System.LoadLibrary could otherwise not load
+   it.  Therefore, on Windows, this code goes into a jpipx.dll that the jpipe.dll
+   wrapper loads with LoadLibraryEx(LOAD_WITH_ALTERED_SEARCH_PATH).
+   The function names in this wrapped code are truncated from the long JNICALL
+   names, as JNICALL causes some "@N" with different numeric values for
+   N (and probably different across 32 and 64 bit) to be added to the symbol
+   names, which the calls to GetProcAddress in wrapper/wrapper.c would otherwise
+   have to take into account.
 */
 
 /*****************************************************************************/

jurt/source/pipe/wrapper/wrapper.c

@@ -26,27 +26,50 @@
 #include "jni.h"
 #include "sal/types.h"
 
-static HMODULE module;
 
-static FARPROC getFunction(char const * name) {
+static HMODULE   module   = NULL;
+static HINSTANCE hInstDLL = NULL;
+static CRITICAL_SECTION CriticalSection;
+
+void InitWrapper(void) {
+    #define MAXPATH 512
+    wchar_t path[MAXPATH];
+    DWORD size;
+
+    size = GetModuleFileNameW(hInstDLL, path, MAXPATH);
+    if (size == 0) {
+        abort();
+    }
+    path[size - 5] = L'x'; /* ...\jpipe.dll -> ...\jpipx.dll */
+    module = LoadLibraryExW(path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
+    if (module == NULL) {
+        abort();
+    }
+}
+
+static FARPROC getFunction(char const * name)
+{
+    {
+        EnterCriticalSection(&CriticalSection);
+
+        if(module == NULL)
+            InitWrapper();
+
+        LeaveCriticalSection(&CriticalSection);
+    }
+
     return GetProcAddress(module, name);
 }
 
 BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved) {
     (void) lpvReserved;
-    if (fdwReason == DLL_PROCESS_ATTACH) {
-        wchar_t path[32767];
-        DWORD size;
-        size = GetModuleFileNameW(hinstDLL, path, 32767);
-        if (size == 0) {
-            return FALSE;
-        }
-        path[size - 5] = L'x'; /* ...\jpipe.dll -> ...\jpipx.dll */
-        module = LoadLibraryExW(path, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
-        if (module == NULL) {
-            return FALSE;
-        }
+
+    if (fdwReason == DLL_PROCESS_ATTACH)
+    {
+        InitializeCriticalSection(&CriticalSection);
+        hInstDLL = hinstDLL;
     }
+
     return TRUE;
 }