dll: FspFsctlEnumServices

inc/winfsp/fsctl.h

@@ -698,6 +698,9 @@ FSP_API NTSTATUS FspFsctlGetVolumeList(PWSTR DevicePath,
 FSP_API NTSTATUS FspFsctlPreflight(PWSTR DevicePath);
 FSP_API NTSTATUS FspFsctlStartService(VOID);
 FSP_API NTSTATUS FspFsctlStopService(VOID);
+FSP_API NTSTATUS FspFsctlEnumServices(
+    VOID (*EnumFn)(PVOID Context, PWSTR ServiceName, BOOLEAN Running),
+    PVOID Context);
 
 typedef struct
 {

src/dll/fsctl.c

@@ -447,17 +447,14 @@ static BOOLEAN FspFsctlRunningInContainer(VOID)
         0, 0);
 }
 
-FSP_API NTSTATUS FspFsctlStartService(VOID)
+static NTSTATUS FspFsctlStartServiceByName(PWSTR DriverName)
 {
-    WCHAR DriverName[256];
     SC_HANDLE ScmHandle = 0;
     SC_HANDLE SvcHandle = 0;
     SERVICE_STATUS ServiceStatus;
     DWORD LastError;
     NTSTATUS Result;
 
-    FspSxsAppendSuffix(DriverName, sizeof DriverName, L"" FSP_FSCTL_DRIVER_NAME);
-
     AcquireSRWLockExclusive(&FspFsctlStartStopServiceLock);
 
     if (FspFsctlRunningInContainer())
@@ -525,6 +522,58 @@ exit:
     return Result;
 }
 
+static VOID FspFsctlStartService_EnumFn(PVOID Context, PWSTR ServiceName, BOOLEAN Running)
+{
+    PWSTR *PDriverName = Context;
+    if (0 == *PDriverName ||
+        0 > invariant_wcscmp(*PDriverName, ServiceName))
+        *PDriverName = ServiceName;
+}
+
+FSP_API NTSTATUS FspFsctlStartService(VOID)
+{
+    /*
+     * With the introduction of side-by-side (SxS) FSD installations,
+     * we revisit how the FSD is started:
+     *
+     * - If the DLL is started in non-SxS mode, we first try to start
+     * the non-SxS FSD. If that fails we then enumerate all SxS FSD's
+     * and make a best guess on which one to start.
+     *
+     * - If the DLL is started in SxS mode, we only attempt to start
+     * the associated SxS FSD.
+     */
+
+    if (L'\0' == FspSxsIdent()[0])
+    {
+        /* non-SxS mode */
+
+        NTSTATUS Result;
+        PWSTR DriverName = 0;
+
+        Result = FspFsctlStartServiceByName(L"" FSP_FSCTL_DRIVER_NAME);
+        if (NT_SUCCESS(Result))
+            return Result;
+
+        /* DO NOT CLOBBER Result. We will return it if our best effort below fails. */
+
+        FspFsctlEnumServices(FspFsctlStartService_EnumFn, &DriverName);
+
+        if (0 == DriverName || !NT_SUCCESS(FspFsctlStartServiceByName(DriverName)))
+            return Result;
+
+        return STATUS_SUCCESS;
+    }
+    else
+    {
+        /* SxS mode */
+
+        WCHAR DriverName[256];
+        FspSxsAppendSuffix(DriverName, sizeof DriverName, L"" FSP_FSCTL_DRIVER_NAME);
+        return FspFsctlStartServiceByName(DriverName);
+    }
+}
+
 FSP_API NTSTATUS FspFsctlStopService(VOID)
 {
     WCHAR DriverName[256];
@@ -615,6 +664,75 @@ exit:
     return Result;
 }
 
+FSP_API NTSTATUS FspFsctlEnumServices(
+    VOID (*EnumFn)(PVOID Context, PWSTR ServiceName, BOOLEAN Running),
+    PVOID Context)
+{
+    SC_HANDLE ScmHandle = 0;
+    LPENUM_SERVICE_STATUSW Services = 0;
+    DWORD Size, ServiceCount;
+    DWORD LastError;
+    NTSTATUS Result;
+
+    ScmHandle = OpenSCManagerW(0, 0, SC_MANAGER_ENUMERATE_SERVICE);
+    if (0 == ScmHandle)
+    {
+        Result = FspNtStatusFromWin32(GetLastError());
+        goto exit;
+    }
+
+    if (!EnumServicesStatusW(ScmHandle,
+        SERVICE_FILE_SYSTEM_DRIVER, SERVICE_STATE_ALL, 0, 0, &Size, &ServiceCount, 0))
+    {
+        LastError = GetLastError();
+        if (ERROR_MORE_DATA != LastError)
+        {
+            Result = FspNtStatusFromWin32(LastError);
+            goto exit;
+        }
+    }
+    if (0 == Size)
+    {
+        Result = STATUS_SUCCESS;
+        goto exit;
+    }
+
+    Services = MemAlloc(Size);
+    if (0 == Services)
+    {
+        Result = STATUS_INSUFFICIENT_RESOURCES;
+        goto exit;
+    }
+
+    if (!EnumServicesStatusW(ScmHandle,
+        SERVICE_FILE_SYSTEM_DRIVER, SERVICE_STATE_ALL, Services, Size, &Size, &ServiceCount, 0))
+    {
+        Result = FspNtStatusFromWin32(GetLastError());
+        goto exit;
+    }
+
+    for (DWORD I = 0; ServiceCount > I; I++)
+    {
+        if (0 != invariant_wcsicmp(Services[I].lpServiceName, L"" FSP_FSCTL_DRIVER_NAME) &&
+            0 != invariant_wcsnicmp(Services[I].lpServiceName,
+            L"" FSP_FSCTL_DRIVER_NAME FSP_SXS_SEPARATOR_STRING,
+            sizeof(FSP_FSCTL_DRIVER_NAME FSP_SXS_SEPARATOR_STRING) - 1))
+            continue;
+        EnumFn(Context,
+            Services[I].lpServiceName,
+            SERVICE_STOPPED != Services[I].ServiceStatus.dwCurrentState);
+    }
+
+    Result = STATUS_SUCCESS;
+
+exit:
+    MemFree(Services);
+    if (0 != ScmHandle)
+        CloseServiceHandle(ScmHandle);
+
+    return Result;
+}
+
 static NTSTATUS FspFsctlFixServiceSecurity(HANDLE SvcHandle)
 {
     /*

src/dll/sxs.c

@@ -93,7 +93,7 @@ static BOOLEAN FspSxsIdentInitializeFromFile(VOID)
     if (0 == Size)
         goto exit;
 
-    FspSxsIdentBuf[0] = L'+';
+    FspSxsIdentBuf[0] = FSP_SXS_SEPARATOR_CHAR;
     memcpy(FspSxsIdentBuf + 1, WBuffer, Size * sizeof(WCHAR));
     FspSxsIdentBuf[1 + Size] = L'\0';
 
@@ -155,7 +155,7 @@ static BOOLEAN FspSxsIdentInitializeFromDirectory(VOID)
     if (0 == Ident)
         goto exit;
 
-    FspSxsIdentBuf[0] = L'+';
+    FspSxsIdentBuf[0] = FSP_SXS_SEPARATOR_CHAR;
     EndQ = FspSxsIdentBuf + (ARRAYSIZE(FspSxsIdentBuf) - 1);
     for (P = Ident, Q = FspSxsIdentBuf + 1; EndP > P && EndQ > Q && L'\\' != *P; P++, Q++)
         *Q = *P;

src/fsptool/fsptool.c

@@ -65,6 +65,7 @@ static void usage(void)
         "    lsvol                           list file system devices (volumes)\n"
         "    id [NAME|SID|UID]               print user id\n"
         "    perm [PATH|SDDL|UID:GID:MODE]   print permissions\n"
+        "    lsdrv                           list drivers\n"
         "    unload                          unload driver (requires load driver priv)\n",
         PROGNAME);
 }
@@ -564,6 +565,25 @@ static int perm(int argc, wchar_t **argv)
     return FspWin32FromNtStatus(Result);
 }
 
+static VOID lsdrv_enumfn(PVOID Context, PWSTR ServiceName, BOOLEAN Running)
+{
+    info("%-4s%S", Running ? "R" : "-", ServiceName);
+}
+
+static int lsdrv(int argc, wchar_t **argv)
+{
+    if (1 != argc)
+        usage();
+
+    NTSTATUS Result;
+
+    Result = FspFsctlEnumServices(lsdrv_enumfn, 0);
+    if (!NT_SUCCESS(Result))
+        return FspWin32FromNtStatus(Result);
+
+    return 0;
+}
+
 static int unload(int argc, wchar_t **argv)
 {
     if (1 != argc)
@@ -598,6 +618,9 @@ int wmain(int argc, wchar_t **argv)
     if (0 == invariant_wcscmp(L"perm", argv[0]))
         return perm(argc, argv);
     else
+    if (0 == invariant_wcscmp(L"lsdrv", argv[0]))
+        return lsdrv(argc, argv);
+    else
     if (0 == invariant_wcscmp(L"unload", argv[0]))
         return unload(argc, argv);
     else

src/shared/ku/config.h

@@ -30,4 +30,10 @@
  */
 #define FSP_CFG_REJECT_EARLY_IRP
 
+/*
+ * SxS separator. The '+' in "WinFsp+20220906T173701Z".
+ */
+#define FSP_SXS_SEPARATOR_CHAR			'+'
+#define FSP_SXS_SEPARATOR_STRING		"+"
+
 #endif

src/sys/sxs.c

@@ -42,7 +42,7 @@ VOID FspSxsIdentInitialize(PUNICODE_STRING DriverName)
     {
         if (L'\\' == *P)
             break;
-        if (L'+' == *P)
+        if (FSP_SXS_SEPARATOR_CHAR == *P)
         {
             Ident = P;
             break;