qga-win: Fix QGA VSS Provider service stop failure

On one hand "guest-fsfreeze-freeze" command, "COM+ System Application service" is
stopped, on the other hand "guest-fsfreeze-thaw" stops QGA VSS Provider service from
"COM+ Application Admin Catalog".
Invoking a series of freeze and thaw commands may result in QGA failing to stop
VSS Provider service as "COM+ System Application service" is stopped, which can
cause some delay in qga response.
In this commit StopService function was changed and VSS Provider service is now
stopped using Winsvc library API.

BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1549425

Signed-off-by: Basil Salman <bsalman@redhat.com>
Signed-off-by: Basil Salman <basil@daynix.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

1 files changed, 20 insertions, 13 deletions

diff --git a/qga/vss-win32/install.cpp b/qga/vss-win32/install.cpp
index a456841..40de133 100644
--- a/qga/vss-win32/install.cpp
+++ b/qga/vss-win32/install.cpp
@@ -19,6 +19,7 @@
 #include <comdef.h>
 #include <comutil.h>
 #include <sddl.h>
+#include <winsvc.h>
 
 #define BUFFER_SIZE 1024
 
@@ -509,26 +510,32 @@ namespace _com_util
     }
 }
 
-/* Stop QGA VSS provider service from COM+ Application Admin Catalog */
-
+/* Stop QGA VSS provider service using Winsvc API  */
 STDAPI StopService(void)
 {
     HRESULT hr;
-    COMInitializer initializer;
-    COMPointer<IUnknown> pUnknown;
-    COMPointer<ICOMAdminCatalog2> pCatalog;
+    SC_HANDLE manager = OpenSCManager(NULL, NULL, SC_MANAGER_ALL_ACCESS);
+    SC_HANDLE service = NULL;
 
-    int count = 0;
+    if (!manager) {
+        errmsg(E_FAIL, "Failed to open service manager");
+        hr = E_FAIL;
+        goto out;
+    }
+    service = OpenService(manager, QGA_PROVIDER_NAME, SC_MANAGER_ALL_ACCESS);
 
-    chk(QGAProviderFind(QGAProviderCount, (void *)&count));
-    if (count) {
-        chk(CoCreateInstance(CLSID_COMAdminCatalog, NULL, CLSCTX_INPROC_SERVER,
-            IID_IUnknown, (void **)pUnknown.replace()));
-        chk(pUnknown->QueryInterface(IID_ICOMAdminCatalog2,
-            (void **)pCatalog.replace()));
-        chk(pCatalog->ShutdownApplication(_bstr_t(QGA_PROVIDER_LNAME)));
+    if (!service) {
+        errmsg(E_FAIL, "Failed to open service");
+        hr =  E_FAIL;
+        goto out;
+    }
+    if (!(ControlService(service, SERVICE_CONTROL_STOP, NULL))) {
+        errmsg(E_FAIL, "Failed to stop service");
+        hr = E_FAIL;
     }
 
 out:
+    CloseServiceHandle(service);
+    CloseServiceHandle(manager);
     return hr;
 }