Move configuration changes to a common file

The config_runtime.h header contains functions that can be used to
manipulate the running configuration. Currently the header contains the
function to create, add, remove and destroy servers.

server/core/config_runtime.c

@@ -0,0 +1,190 @@
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl.
+ *
+ * Change Date: 2019-07-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+#include <maxscale/config_runtime.h>
+#include <maxscale/gwdirs.h>
+#include <maxscale/spinlock.h>
+
+static SPINLOCK crt_lock = SPINLOCK_INIT;
+
+bool runtime_link_server(SERVER *server, const char *target)
+{
+    spinlock_acquire(&crt_lock);
+
+    bool rval = false;
+    SERVICE *service = service_find(target);
+    MONITOR *monitor = service ? NULL : monitor_find(target);
+
+    if (service || monitor)
+    {
+        rval = true;
+
+        if (service)
+        {
+            serviceAddBackend(service, server);
+            service_serialize_servers(service);
+        }
+        else if (monitor)
+        {
+            monitorAddServer(monitor, server);
+            monitor_serialize_servers(monitor);
+        }
+
+        const char *type = service ? "service" : "monitor";
+
+        MXS_NOTICE("Added server '%s' to %s '%s'", server->unique_name, type, target);
+    }
+
+    spinlock_release(&crt_lock);
+    return rval;
+}
+
+bool runtime_unlink_server(SERVER *server, const char *target)
+{
+    spinlock_acquire(&crt_lock);
+
+    bool rval = false;
+    SERVICE *service = service_find(target);
+    MONITOR *monitor = service ? NULL : monitor_find(target);
+
+    if (service || monitor)
+    {
+        rval = true;
+
+        if (service)
+        {
+            serviceRemoveBackend(service, server);
+            service_serialize_servers(service);
+        }
+        else if (monitor)
+        {
+            monitorRemoveServer(monitor, server);
+            monitor_serialize_servers(monitor);
+        }
+
+        const char *type = service ? "service" : "monitor";
+        MXS_NOTICE("Removed server '%s' from %s '%s'", server->unique_name, type, target);
+    }
+
+    spinlock_release(&crt_lock);
+    return rval;
+}
+
+
+bool runtime_create_server(const char *name, const char *address, const char *port,
+                           const char *protocol, const char *authenticator,
+                           const char *authenticator_options)
+{
+    spinlock_acquire(&crt_lock);
+    bool rval = false;
+
+    if (server_find_by_unique_name(name) == NULL)
+    {
+        // TODO: Get default values from the protocol module
+        if (port == NULL)
+        {
+            port = "3306";
+        }
+        if (protocol == NULL)
+        {
+            protocol = "MySQLBackend";
+        }
+        if (authenticator == NULL && (authenticator = get_default_authenticator(protocol)) == NULL)
+        {
+            MXS_ERROR("No authenticator defined for server '%s' and no default "
+                      "authenticator for protocol '%s'.", name, protocol);
+            spinlock_release(&crt_lock);
+            return false;
+        }
+
+        /** First check if this service has been created before */
+        SERVER *server = server_find_destroyed(name, protocol, authenticator,
+                                               authenticator_options);
+
+        if (server)
+        {
+            /** Found old server, replace network details with new ones and
+             * reactivate it */
+            snprintf(server->name, sizeof(server->name), "%s", address);
+            server->port = atoi(port);
+            server->is_active = true;
+            rval = true;
+        }
+        else
+        {
+            /**
+             * server_alloc will add the server to the global list of
+             * servers so we don't need to manually add it.
+             */
+            server = server_alloc(name, address, atoi(port), protocol,
+                                  authenticator, authenticator_options);
+        }
+
+        if (server && server_serialize(server))
+        {
+            rval = true;
+        }
+    }
+
+    spinlock_release(&crt_lock);
+    return rval;
+}
+
+bool runtime_destroy_server(SERVER *server)
+{
+    spinlock_acquire(&crt_lock);
+    bool rval = false;
+
+    if (service_server_in_use(server) || monitor_server_in_use(server))
+    {
+        MXS_ERROR("Cannot destroy server '%s' as it is used by at least one "
+                  "service or monitor", server->unique_name);
+    }
+    else
+    {
+        char filename[PATH_MAX];
+        snprintf(filename, sizeof(filename), "%s/%s.cnf", get_config_persistdir(),
+                 server->unique_name);
+
+        if (unlink(filename) == -1)
+        {
+            if (errno != ENOENT)
+            {
+                char err[MXS_STRERROR_BUFLEN];
+                MXS_ERROR("Failed to remove persisted server configuration '%s': %d, %s",
+                          filename, errno, strerror_r(errno, err, sizeof(err)));
+            }
+            else
+            {
+                rval = true;
+                MXS_WARNING("Server '%s' was not created at runtime. Remove the "
+                            "server manually from the correct configuration file.",
+                            server->unique_name);
+            }
+        }
+        else
+        {
+            rval = true;
+        }
+
+        if (rval)
+        {
+            MXS_NOTICE("Destroyed server '%s' at %s:%u", server->unique_name,
+                       server->name, server->port);
+            server->is_active = false;
+        }
+    }
+
+    spinlock_release(&crt_lock);
+    return rval;
+}