dll: streamline DLL_PROCESS_ATTACH, DLL_PROCESS_DETACH handling

src/dll/eventlog.c

@@ -26,6 +26,24 @@ static INIT_ONCE FspEventLogInitOnce = INIT_ONCE_STATIC_INIT;
 static BOOL WINAPI FspEventLogRegisterEventSource(
     PINIT_ONCE InitOnce, PVOID Parameter, PVOID *Context);
 
+VOID FspEventLogInitialize(BOOLEAN Dynamic)
+{
+}
+
+VOID FspEventLogFinalize(BOOLEAN Dynamic)
+{
+    /*
+     * This function is called during DLL_PROCESS_DETACH. We must therefore keep
+     * finalization tasks to a minimum.
+     *
+     * We must deregister our event source (if any). We only do so if the library
+     * is being explicitly unloaded (rather than the process exiting).
+     */
+
+    if (Dynamic && 0 != FspEventLogHandle)
+        DeregisterEventSource(FspEventLogHandle);
+}
+
 FSP_API VOID FspEventLog(ULONG Type, PWSTR Format, ...)
 {
     va_list ap;

src/dll/fs.c

@@ -27,11 +27,11 @@ static FSP_FILE_SYSTEM_INTERFACE FspFileSystemNullInterface;
 static CRITICAL_SECTION FspFileSystemMountListGuard;
 static LIST_ENTRY FspFileSystemMountList = { &FspFileSystemMountList, &FspFileSystemMountList };
 
-VOID FspFileSystemInitialize(VOID)
+VOID FspFileSystemInitialize(BOOLEAN Dynamic)
 {
     /*
-     * This function is called during DLL_PROCESS_ATTACH. We must therefore keep initialization
-     * tasks to a minimum.
+     * This function is called during DLL_PROCESS_ATTACH. We must therefore keep
+     * initialization tasks to a minimum.
      *
      * Initialization of synchronization objects is allowed! See:
      *     https://msdn.microsoft.com/en-us/library/windows/desktop/dn633971(v=vs.85).aspx
@@ -40,16 +40,11 @@ VOID FspFileSystemInitialize(VOID)
     InitializeCriticalSection(&FspFileSystemMountListGuard);
 }
 
-VOID FspFileSystemFinalize(VOID)
+VOID FspFileSystemFinalize(BOOLEAN Dynamic)
 {
     /*
-     * This function is called during DLL_PROCESS_DETACH. We must therefore keep finalization
-     * tasks to a minimum.
-     *
-     * Very few things can be safely done during DLL_PROCESS_DETACH. See:
-     *     https://msdn.microsoft.com/en-us/library/windows/desktop/dn633971(v=vs.85).aspx
-     *     https://blogs.msdn.microsoft.com/oldnewthing/20070503-00/?p=27003/
-     *     https://blogs.msdn.microsoft.com/oldnewthing/20100122-00/?p=15193/
+     * This function is called during DLL_PROCESS_DETACH. We must therefore keep
+     * finalization tasks to a minimum.
      *
      * We enter our FspFileSystemMountListGuard critical section here and then attempt to cleanup
      * our mount points using DefineDosDeviceW. On Vista and later orphaned critical sections
@@ -60,6 +55,9 @@ VOID FspFileSystemFinalize(VOID)
      * out to CSRSS, which is probably not the safest thing to do when in DllMain! There is also
      * some evidence that it may attempt to load DLL's under some circumstances, which is a
      * definite no-no as we are under the loader lock!
+     *
+     * We only delete the criticaly section when being dynamically unloaded. On process exit the
+     * OS will clean it up for us.
      */
 
     FSP_FILE_SYSTEM *FileSystem;
@@ -79,6 +77,9 @@ VOID FspFileSystemFinalize(VOID)
     }
 
     LeaveCriticalSection(&FspFileSystemMountListGuard);
+
+    if (Dynamic)
+        DeleteCriticalSection(&FspFileSystemMountListGuard);
 }
 
 FSP_API NTSTATUS FspFileSystemCreate(PWSTR DevicePath,

src/dll/library.c

@@ -22,6 +22,8 @@ HANDLE ProcessHeap;
 
 BOOL WINAPI DllMain(HINSTANCE Instance, DWORD Reason, PVOID Reserved)
 {
+    BOOLEAN Dynamic;
+
     switch (Reason)
     {
     case DLL_PROCESS_ATTACH:
@@ -29,11 +31,36 @@ BOOL WINAPI DllMain(HINSTANCE Instance, DWORD Reason, PVOID Reserved)
         ProcessHeap = GetProcessHeap();
         if (0 == ProcessHeap)
             return FALSE;
-        FspNtStatusInitialize();
-        FspFileSystemInitialize();
+
+        /*
+         * These functions are called during DLL_PROCESS_ATTACH. We must therefore keep
+         * initialization tasks to a minimum.
+         *
+         * See the DLL best practices document:
+         *     https://msdn.microsoft.com/en-us/library/windows/desktop/dn633971(v=vs.85).aspx
+         */
+        Dynamic = 0 == Reserved;
+        FspNtStatusInitialize(Dynamic);
+        FspEventLogInitialize(Dynamic);
+        FspFileSystemInitialize(Dynamic);
+        FspServiceInitialize(Dynamic);
         break;
+
     case DLL_PROCESS_DETACH:
-        FspFileSystemFinalize();
+        /*
+         * These functions are called during DLL_PROCESS_DETACH. We must therefore keep
+         * finalization tasks to a minimum.
+         *
+         * See the following documents:
+         *     https://msdn.microsoft.com/en-us/library/windows/desktop/dn633971(v=vs.85).aspx
+         *     https://blogs.msdn.microsoft.com/oldnewthing/20070503-00/?p=27003/
+         *     https://blogs.msdn.microsoft.com/oldnewthing/20100122-00/?p=15193/
+         */
+        Dynamic = 0 == Reserved;
+        FspServiceFinalize(Dynamic);
+        FspFileSystemFinalize(Dynamic);
+        FspEventLogFinalize(Dynamic);
+        FspNtStatusFinalize(Dynamic);
         break;
     }
 

src/dll/library.h

@@ -103,17 +103,19 @@ BOOLEAN RemoveEntryList(PLIST_ENTRY Entry)
     return Flink == Blink;
 }
 
-VOID FspNtStatusInitialize(VOID);
-
-VOID FspFileSystemInitialize(VOID);
-VOID FspFileSystemFinalize(VOID);
+VOID FspNtStatusInitialize(BOOLEAN Dynamic);
+VOID FspNtStatusFinalize(BOOLEAN Dynamic);
+VOID FspEventLogInitialize(BOOLEAN Dynamic);
+VOID FspEventLogFinalize(BOOLEAN Dynamic);
+VOID FspFileSystemInitialize(BOOLEAN Dynamic);
+VOID FspFileSystemFinalize(BOOLEAN Dynamic);
+VOID FspServiceInitialize(BOOLEAN Dynamic);
+VOID FspServiceFinalize(BOOLEAN Dynamic);
 
 NTSTATUS FspFsctlRegister(VOID);
 NTSTATUS FspFsctlUnregister(VOID);
-
 NTSTATUS FspNpRegister(VOID);
 NTSTATUS FspNpUnregister(VOID);
-
 NTSTATUS FspEventLogRegister(VOID);
 NTSTATUS FspEventLogUnregister(VOID);
 

src/dll/ntstatus.c

@@ -19,11 +19,11 @@
 
 static ULONG (WINAPI *FspRtlNtStatusToDosError)(NTSTATUS Status);
 
-VOID FspNtStatusInitialize(VOID)
+VOID FspNtStatusInitialize(BOOLEAN Dynamic)
 {
     /*
-     * This function is called during DLL_PROCESS_ATTACH. We must therefore keep initialization
-     * tasks to a minimum.
+     * This function is called during DLL_PROCESS_ATTACH. We must therefore keep
+     * initialization tasks to a minimum.
      *
      * GetModuleHandle/GetProcAddress is allowed (because they are kernel32 API's)! See:
      *     https://msdn.microsoft.com/en-us/library/windows/desktop/dn633971(v=vs.85).aspx
@@ -36,6 +36,10 @@ VOID FspNtStatusInitialize(VOID)
         FspRtlNtStatusToDosError = (PVOID)GetProcAddress(Handle, "RtlNtStatusToDosError");
 }
 
+VOID FspNtStatusFinalize(BOOLEAN Dynamic)
+{
+}
+
 FSP_API NTSTATUS FspNtStatusFromWin32(DWORD Error)
 {
     switch (Error)

src/dll/service.c

@@ -46,6 +46,14 @@ static DWORD WINAPI FspServiceStopRoutine(PVOID Context);
 static DWORD WINAPI FspServiceInteractiveThread(PVOID Context);
 static BOOL WINAPI FspServiceConsoleCtrlHandler(DWORD CtrlType);
 
+VOID FspServiceInitialize(BOOLEAN Dynamic)
+{
+}
+
+VOID FspServiceFinalize(BOOLEAN Dynamic)
+{
+}
+
 static inline FSP_SERVICE *FspServiceFromTable(VOID)
 {
     FSP_SERVICE *Service = 0;