virlog: Introduce virLogDefineOutputs

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

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

src/libvirt_private.syms

@@ -1871,6 +1871,7 @@ virLockSpaceReleaseResourcesForOwner;
 # util/virlog.h
 virLogDefineFilter;
 virLogDefineOutput;
+virLogDefineOutputs;
 virLogFilterFree;
 virLogFilterListFree;
 virLogFilterNew;

src/util/virlog.c

@@ -1681,3 +1681,28 @@ virLogFindOutput(virLogOutputPtr *outputs, size_t noutputs,
 
     return -1;
 }
+
+
+/**
+ * virLogDefineOutputs:
+ * @outputs: new set of outputs to be defined
+ * @noutputs: number of outputs in @outputs
+ *
+ * Resets any existing set of outputs and defines a completely new one.
+ *
+ * Returns number of outputs successfully defined or -1 in case of error;
+ */
+int
+virLogDefineOutputs(virLogOutputPtr *outputs, size_t noutputs)
+{
+    if (virLogInitialize() < 0)
+        return -1;
+
+    virLogLock();
+    virLogResetOutputs();
+    virLogOutputs = outputs;
+    virLogNbOutputs = noutputs;
+    virLogUnlock();
+
+    return 0;
+}

src/util/virlog.h

@@ -237,5 +237,7 @@ virLogFilterPtr virLogFilterNew(const char *match,
                                 unsigned int flags) ATTRIBUTE_NONNULL(1);
 int virLogFindOutput(virLogOutputPtr *outputs, size_t noutputs,
                      virLogDestination dest, const void *opaque);
+int virLogDefineOutputs(virLogOutputPtr *outputs,
+                        size_t noutputs) ATTRIBUTE_NONNULL(1);
 
 #endif