internal/dlopen: fix test and run in CI

internal/dlopen/dlopen_example.go

@@ -0,0 +1,57 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+//go:build linux
+// +build linux
+
+package dlopen
+
+// #include <string.h>
+// #include <stdlib.h>
+//
+// int
+// my_strlen(void *f, const char *s)
+// {
+//   size_t (*strlen)(const char *);
+//
+//   strlen = (size_t (*)(const char *))f;
+//   return strlen(s);
+// }
+import "C"
+
+import (
+	"fmt"
+	"unsafe"
+)
+
+func strlen(libs []string, s string) (int, error) {
+	h, err := GetHandle(libs)
+	if err != nil {
+		return -1, fmt.Errorf(`couldn't get a handle to the library: %v`, err)
+	}
+	defer h.Close()
+
+	f := "strlen"
+	cs := C.CString(s)
+	defer C.free(unsafe.Pointer(cs))
+
+	strlen, err := h.GetSymbolPointer(f)
+	if err != nil {
+		return -1, fmt.Errorf(`couldn't get symbol %q: %v`, f, err)
+	}
+
+	len := C.my_strlen(strlen, cs)
+
+	return int(len), nil
+}

scripts/ci-runner.sh

@@ -6,7 +6,7 @@ PROJ="go-systemd"
 ORG_PATH="github.com/coreos"
 REPO_PATH="${ORG_PATH}/${PROJ}"
 
-PACKAGES="activation daemon dbus journal login1 machine1 sdjournal unit util import1"
+PACKAGES="activation daemon dbus internal/dlopen journal login1 machine1 sdjournal unit util import1"
 EXAMPLES="activation listen udpconn"
 
 function build_source {