virlog: Introduce virLogDefineFilters

Prepare a method that only defines a set of filters. It takes a list of
filters, preferably created by virLogParseFilters. The original set of filters
is reset and replaced by the new user-provided set of filters.

Signed-off-by: Erik Skultety <eskultet@redhat.com>

src/libvirt_private.syms

@@ -1870,6 +1870,7 @@ virLockSpaceReleaseResourcesForOwner;
 
 # util/virlog.h
 virLogDefineFilter;
+virLogDefineFilters;
 virLogDefineOutput;
 virLogDefineOutputs;
 virLogFilterFree;

src/util/virlog.c

@@ -1706,3 +1706,30 @@ virLogDefineOutputs(virLogOutputPtr *outputs, size_t noutputs)
 
     return 0;
 }
+
+
+/**
+ * virLogDefineFilters:
+ * @filters: new set of filters to be defined
+ * @nfilters: number of filters in @filters
+ *
+ * Resets any existing set of filters and defines a completely new one. The
+ * resulting set can also be empty in which case NULL should be passed to
+ * @filters.
+ *
+ * Returns 0 on success or -1 in case of error.
+ */
+int
+virLogDefineFilters(virLogFilterPtr *filters, size_t nfilters)
+{
+    if (virLogInitialize() < 0)
+        return -1;
+
+    virLogLock();
+    virLogResetFilters();
+    virLogFilters = filters;
+    virLogNbFilters = nfilters;
+    virLogUnlock();
+
+    return 0;
+}

src/util/virlog.h

@@ -239,5 +239,6 @@ int virLogFindOutput(virLogOutputPtr *outputs, size_t noutputs,
                      virLogDestination dest, const void *opaque);
 int virLogDefineOutputs(virLogOutputPtr *outputs,
                         size_t noutputs) ATTRIBUTE_NONNULL(1);
+int virLogDefineFilters(virLogFilterPtr *filters, size_t nfilters);
 
 #endif