agent: utilize IWD_MODULE

Converts agent into an IWD module. This removes the dbus dependency
on agent. Since dbus is initialized very early we can assume
dbus_get_bus is going to return a valid object.

src/agent.c

@@ -29,6 +29,7 @@
 #include <ell/ell.h>
 #include "src/dbus.h"
 #include "src/agent.h"
+#include "src/iwd.h"
 
 static unsigned int next_request_id = 0;
 
@@ -619,8 +620,10 @@ static bool release_agent(void *data, void *user_data)
 	return true;
 }
 
-bool agent_init(struct l_dbus *dbus)
+static int agent_init(void)
 {
+	struct l_dbus *dbus = dbus_get_bus();
+
 	agents = l_queue_new();
 
 	if (!l_dbus_register_interface(dbus, IWD_AGENT_MANAGER_INTERFACE,
@@ -628,7 +631,7 @@ bool agent_init(struct l_dbus *dbus)
 						NULL, false)) {
 		l_info("Unable to register %s interface",
 				IWD_AGENT_MANAGER_INTERFACE);
-		return false;
+		return -EIO;
 	}
 
 	if (!l_dbus_object_add_interface(dbus, IWD_AGENT_MANAGER_PATH,
@@ -637,24 +640,26 @@ bool agent_init(struct l_dbus *dbus)
 		l_info("Unable to register the agent manager object on '%s'",
 				IWD_AGENT_MANAGER_PATH);
 		l_dbus_unregister_interface(dbus, IWD_AGENT_MANAGER_INTERFACE);
-		return false;
+		return -EIO;
 	}
 
-	return true;
+	return 0;
 }
 
-bool agent_exit(struct l_dbus *dbus)
+static void agent_exit(void)
 {
+	struct l_dbus *dbus = dbus_get_bus();
+
 	l_dbus_unregister_object(dbus, IWD_AGENT_MANAGER_PATH);
 	l_dbus_unregister_interface(dbus, IWD_AGENT_MANAGER_INTERFACE);
 
 	l_queue_destroy(agents, agent_free);
 	agents = NULL;
-
-	return true;
 }
 
 void agent_shutdown(void)
 {
 	l_queue_foreach_remove(agents, release_agent, NULL);
 }
+
+IWD_MODULE(agent, agent_init, agent_exit);

src/agent.h

@@ -37,8 +37,6 @@ typedef void (*agent_request_user_name_passwd_func_t) (enum agent_result result,
 					void *user_data);
 typedef void (*agent_request_destroy_func_t)(void *user_data);
 
-bool agent_init(struct l_dbus *dbus);
-bool agent_exit(struct l_dbus *dbus);
 void agent_shutdown(void);
 
 unsigned int agent_request_passphrase(const char *path,

src/dbus.c

@@ -210,12 +210,11 @@ struct l_dbus *dbus_get_bus(void)
 bool dbus_init(struct l_dbus *dbus)
 {
 	g_dbus = dbus;
-	return agent_init(dbus);
+	return true;
 }
 
 void dbus_exit(void)
 {
-	agent_exit(g_dbus);
 	g_dbus = NULL;
 }