Add basic support for dynamically loadable plugins

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

plugins/Makefile

@@ -0,0 +1,32 @@
+# Plugin based services architecture for finit -*-Makefile-*-
+CFLAGS      = -fPIC -g -Os -I..
+CPPFLAGS    = -W -Wall
+LDFLAGS     = -shared 
+PLUGINS     = foo.so
+DEPS        = $(addprefix .,$(PLUGINS:.so=.d))
+
+include ../common.mk
+
+all: $(PLUGINS)
+
+clean:
+	$(RM) $(PLUGINS) *.o
+
+distclean: clean
+	$(RM) $(JUNK) $(DEPS)
+
+install: all
+	@for plugin in $(PLUGINS); do \
+		echo "  INSTALL $(PLUGIN_DIR)/$$plugin"; \
+		cp $$plugin $(PLUGIN_DIR); \
+	done
+
+uninstall:
+	@for plugin in $(PLUGINS); do \
+		echo "  RM      $(PLUGIN_DIR)/$$plugin"; \
+		rm $(PLUGIN_DIR)/$$plugin; \
+	done
+
+ifneq ($(MAKECMDGOALS),clean)
+ -include $(DEPS)
+endif

plugins/foo.c

@@ -0,0 +1,54 @@
+/* Test of plugin to dynamic-linking daemon.
+ *
+ * Copyright (c) 2012  Joachim Nilsson <troglobit@gmail.com>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <stdio.h>
+#include "plugin.h"
+
+#define PLUGIN_NAME "foo"
+
+static void service(void *arg __unused)
+{
+	printf("Service %s\n", PLUGIN_NAME);
+}
+
+static plugin_t plugin = {
+        .name = PLUGIN_NAME,
+        .svc = {
+		.cb = service,
+        },
+};
+
+static void init_plugin(void)
+{
+	plugin_register(&plugin);
+}
+
+static void exit_plugin(void)
+{
+	plugin_unregister(&plugin);
+}
+
+PLUGIN_INIT(init_plugin)
+PLUGIN_EXIT(exit_plugin)
+
+/**
+ * Local Variables:
+ *  version-control: t
+ *  indent-tabs-mode: t
+ *  c-file-style: "linux"
+ * End:
+ */