Add initial plugin header

This patch adds the first preliminary draft plugin description. It is
missing many things, most importantly documentation.

More importantly it is likely not yet complete.

Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>

2 files changed, 77 insertions, 2 deletions

diff --git a/src/lib/Makefile.am b/src/lib/Makefile.am
index 0eaf568..fc64133 100644
--- a/src/lib/Makefile.am
+++ b/src/lib/Makefile.am
@@ -3,6 +3,7 @@ MAINTAINERCLEANFILES = Makefile.in
 AM_CPPFLAGS = \
 -I$(top_srcdir)/src/lib \
 -I$(top_builddir)/src/lib \
+-I$(top_srcdir)/src/include \
 -DPACKAGE_LIB_DIR=\"$(libdir)\" \
 -DPACKAGE_DATA_DIR=\"$(datadir)/$(PACKAGE)\" \
 @EFL_CFLAGS@ \
@@ -13,6 +14,6 @@ lib_LTLIBRARIES = libengagement.la
 includes_HEADERS = engagement.h
 includesdir = $(includedir)/engagement-@VMAJ@
 
-libengagement_la_SOURCES = engagement.c
-libengagement_la_LIBADD = @EFL_LIBS@ -lm
+libengagement_la_SOURCES = engagement.c plugin.c
+libengagement_la_LIBADD = @EFL_LIBS@ @LIBDL@
 libengagement_la_LDFLAGS = @EFL_LTLIBRARY_FLAGS@
diff --git a/src/lib/plugin.c b/src/lib/plugin.c
new file mode 100644
index 0000000..09df8de
--- /dev/null
+++ b/src/lib/plugin.c
@@ -0,0 +1,74 @@
+/*
+ * (c) Copyright 2016 Olliver Schinagl
+ * Author: Olliver Schinagl <oliver@schinagl.nl>
+ *
+ * SPDX-License-Identifier:	AGPL-3.0+
+ */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <dlfcn.h>
+
+#include <engagement/plugin.h>
+
+struct plugin *plugin_load(const char *path)
+{
+	struct plugin *plugin;
+	void *handle;
+
+	handle = dlopen(path, RTLD_LAZY); /* TODO check if RTLD_LAZY is what we want */
+	if (!handle) {
+		// TODO EINA_LOG
+		fprintf(stderr, "dlopen failed: %s\n", dlerror());
+		return NULL;
+	}
+
+	/* TODO use macro's to allow for static inclusion */
+	/* TODO use dlvsym() if available */
+	plugin = (struct plugin *)dlsym(handle, PLUGIN_SYMBOL);
+	if(!plugin) {
+		// TODO EINA_LOG
+		fprintf(stderr, "dlsym failed%s\n", dlerror());
+		return NULL;
+	}
+
+	if (plugin->magic != PLUGIN_MAGIC) {
+		// TODO EINA_LOG
+		fprintf(stderr, "Failed to init plugin, magic mismatch, plugin corrupt?\n");
+		return NULL;
+	}
+	plugin->_handle = handle;
+
+	if (plugin->load)
+		plugin->load();
+
+	return plugin;
+}
+
+int plugin_unload(struct plugin *plugin)
+{
+	int error;
+
+	if (!plugin) {
+		// TODO EINA_LOG
+		fprintf(stderr, "Cannot unload plugin %p.\n", plugin);
+		return -EFAULT;
+	}
+	
+	if (plugin->unload)
+		plugin->unload();
+
+	if (!plugin->_handle) {
+		// TODO EINA_LOG
+		fprintf(stderr, "Error, no handle for plugin %s\n",
+			       plugin->info.name);
+		return -EFAULT;
+	}
+	error = dlclose(plugin->_handle);
+	if (error)
+		// TODO EINA_LOG
+		fprintf(stderr, "Failed to close %s\n", dlerror());
+
+	return error;
+}