Annotate some virConnectPtr as mandatory non-null

Use the ATTRIBUTE_NONNULL annotation to mark some virConnectPtr
args as mandatory non-null so the compiler can warn of mistakes

* src/conf/domain_event.h: All virConnectPtr args must be non-null
* src/qemu/qemu_conf.h: qemudBuildCommandLine and
  qemudNetworkIfaceConnect() must be given non-null connection
* tests/qemuxml2argvtest.c: Provide a non-null (dummy) connection to
  qemudBuildCommandLine()

src/conf/domain_event.h

@@ -50,18 +50,23 @@ int virDomainEventCallbackListAdd(virConnectPtr conn,
                                   virDomainEventCallbackListPtr cbList,
                                   virConnectDomainEventCallback callback,
                                   void *opaque,
-                                  virFreeCallback freecb);
+                                  virFreeCallback freecb)
+    ATTRIBUTE_NONNULL(1);
 
 int virDomainEventCallbackListRemove(virConnectPtr conn,
                                      virDomainEventCallbackListPtr cbList,
-                                     virConnectDomainEventCallback callback);
+                                     virConnectDomainEventCallback callback)
+    ATTRIBUTE_NONNULL(1);
 
 int virDomainEventCallbackListRemoveConn(virConnectPtr conn,
-                                         virDomainEventCallbackListPtr cbList);
+                                         virDomainEventCallbackListPtr cbList)
+    ATTRIBUTE_NONNULL(1);
 
 int virDomainEventCallbackListMarkDelete(virConnectPtr conn,
                                          virDomainEventCallbackListPtr cbList,
-                                         virConnectDomainEventCallback callback);
+                                         virConnectDomainEventCallback callback)
+    ATTRIBUTE_NONNULL(1);
+
 int virDomainEventCallbackListPurgeMarked(virDomainEventCallbackListPtr cbList);
 
 /**

src/qemu/qemu_conf.h

@@ -188,7 +188,8 @@ int         qemudBuildCommandLine       (virConnectPtr conn,
                                          const char ***retenv,
                                          int **tapfds,
                                          int *ntapfds,
-                                         const char *migrateFrom);
+                                         const char *migrateFrom)
+    ATTRIBUTE_NONNULL(1);
 
 /* With vlan == -1, use netdev syntax, else old hostnet */
 char * qemuBuildHostNetStr(virDomainNetDefPtr net,
@@ -241,7 +242,8 @@ char * qemuBuildUSBHostdevDevStr(virDomainHostdevDefPtr dev);
 int         qemudNetworkIfaceConnect    (virConnectPtr conn,
                                          struct qemud_driver *driver,
                                          virDomainNetDefPtr net,
-                                         unsigned long long qemuCmdFlags);
+                                         unsigned long long qemuCmdFlags)
+    ATTRIBUTE_NONNULL(1);
 
 int         qemudProbeMachineTypes      (const char *binary,
                                          virCapsGuestMachinePtr **machines,

tests/qemuxml2argvtest.c

@@ -13,6 +13,7 @@
 #include "internal.h"
 #include "testutils.h"
 #include "qemu/qemu_conf.h"
+#include "datatypes.h"
 
 #include "testutilsqemu.h"
 
@@ -36,6 +37,10 @@ static int testCompareXMLToArgvFiles(const char *xml,
     unsigned long long flags;
     virDomainDefPtr vmdef = NULL;
     virDomainChrDef monitor_chr;
+    virConnectPtr conn;
+
+    if (!(conn = virGetConnect()))
+        goto fail;
 
     if (virtTestLoadFile(cmd, &expectargv, MAX_FILE) < 0)
         goto fail;
@@ -75,7 +80,7 @@ static int testCompareXMLToArgvFiles(const char *xml,
     }
 
 
-    if (qemudBuildCommandLine(NULL, &driver,
+    if (qemudBuildCommandLine(conn, &driver,
                               vmdef, &monitor_chr, 0, flags,
                               &argv, &qenv,
                               NULL, NULL, migrateFrom) < 0)
@@ -137,6 +142,7 @@ static int testCompareXMLToArgvFiles(const char *xml,
         free(qenv);
     }
     virDomainDefFree(vmdef);
+    virUnrefConnect(conn);
     return ret;
 }