diff --git a/lib/api/request.cpp b/lib/api/request.cpp
index 3db96ef4f..81124152f 100644
--- a/lib/api/request.cpp
+++ b/lib/api/request.cpp
@@ -42,7 +42,7 @@ std::string Request::toString()
 
 Request * RequestFactory::create(Session *s, const std::string &uri, Session::Method meth, unsigned long ct)
 {
-	s->logger->info("Trying to find request handler for: uri={}", uri);
+	s->logger->info("Lookup request handler for: uri={}", uri);
 
 	for (auto *rf : plugin::Registry::lookup<RequestFactory>()) {
 		std::smatch mr;
diff --git a/lib/format.cpp b/lib/format.cpp
index 0072a53f3..27f4522f1 100644
--- a/lib/format.cpp
+++ b/lib/format.cpp
@@ -62,7 +62,7 @@ Format * FormatFactory::make(json_t *json)
 		return f;
 	}
 	else
-		throw ConfigError(json, "Invalid format config");
+		throw ConfigError(json, "node-config-format", "Invalid format config");
 }
 
 Format * FormatFactory::make(const std::string &format)
diff --git a/lib/nodes/file.cpp b/lib/nodes/file.cpp
index 0917ac980..37d36987c 100644
--- a/lib/nodes/file.cpp
+++ b/lib/nodes/file.cpp
@@ -87,7 +87,7 @@ int file_parse(struct vnode *n, json_t *json)
 
 	int ret;
 	json_error_t err;
-	json_t *json_format;
+	json_t *json_format = nullptr;
 
 	const char *uri_tmpl = nullptr;
 	const char *eof = nullptr;
diff --git a/lib/nodes/signal_generator.cpp b/lib/nodes/signal_generator.cpp
index 981aaa750..8693b3c1e 100644
--- a/lib/nodes/signal_generator.cpp
+++ b/lib/nodes/signal_generator.cpp
@@ -352,7 +352,7 @@ int signal_generator_read(struct vnode *n, struct sample * const smps[], unsigne
 	t->length = MIN(s->values, t->capacity);
 	t->signals = &n->in.signals;
 
-	for (unsigned i = 0; i < MIN(s->values, t->capacity); i++) {
+	for (unsigned i = 0; i < t->length; i++) {
 		switch (s->type[i]) {
 			case signal_generator::SignalType::CONSTANT:
 				t->data[i].f = s->offset[i] + s->amplitude[i];
diff --git a/src/villas-hook.cpp b/src/villas-hook.cpp
index e5b7a5a39..a376d1bfb 100644
--- a/src/villas-hook.cpp
+++ b/src/villas-hook.cpp
@@ -107,18 +107,19 @@ protected:
 
 	void usage()
 	{
-		std::cout << "Usage: villas-hook [OPTIONS] NAME [[PARAM1] [PARAM2] ...]" << std::endl
+		std::cout << "Usage: villas-hook [OPTIONS] NAME" << std::endl
 			<< "  NAME      the name of the hook function" << std::endl
 			<< "  PARAM*    a string of configuration settings for the hook" << std::endl
 			<< "  OPTIONS is one or more of the following options:" << std::endl
-			<< "    -c CONFIG a JSON file containing just the hook configuration" << std::endl
-			<< "    -f FMT    the input data format" << std::endl
-			<< "    -F FMT    the output data format (defaults to input format)" << std::endl
-			<< "    -t DT     the data-type format string" << std::endl
-			<< "    -d LVL    set debug level to LVL" << std::endl
-			<< "    -v CNT    process CNT smps at once" << std::endl
-			<< "    -h        show this help" << std::endl
-			<< "    -V        show the version of the tool" << std::endl << std::endl;
+			<< "    -c CONFIG       a JSON file containing just the hook configuration" << std::endl
+			<< "    -f FMT          the input data format" << std::endl
+			<< "    -F FMT          the output data format (defaults to input format)" << std::endl
+			<< "    -t DT           the data-type format string" << std::endl
+			<< "    -d LVL          set debug level to LVL" << std::endl
+			<< "    -v CNT          process CNT smps at once" << std::endl
+			<< "    -o PARAM=VALUE  provide parameters for hook configuration" << std::endl
+			<< "    -h              show this help" << std::endl
+			<< "    -V              show the version of the tool" << std::endl << std::endl;
 
 		std::cout << "Supported hooks:" << std::endl;
 		for (Plugin *p : Registry::lookup<HookFactory>())