diff --git a/configure.ac b/configure.ac
index 67dbfbf..e5127da 100644
--- a/configure.ac
+++ b/configure.ac
@@ -22,7 +22,7 @@ test_gcc_flag() {
 
 # We use gnu99 instead of c99 because many have interpreted the standard
 # in a way that int64_t isn't defined on non-64 bit platforms.
-CFLAGS="-Os -std=gnu99 -Wall -Wextra -pipe  -Wold-style-definition -Wfloat-equal -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wendif-labels -Wpointer-arith -Wcast-align -Wwrite-strings -Winline -Wno-unused-parameter -finline-small-functions -Wno-unused-result -fstack-protector -D_FORTIFY_SOURCE=2 -Wl,-z,relro,-z,now -fPIE -fpie -pie"
+CFLAGS="-Os -std=gnu99 -Wall -Wextra -pipe  -Wold-style-definition -Wfloat-equal -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wendif-labels -Wpointer-arith -Wcast-align -Wwrite-strings -Winline -finline-small-functions -fstack-protector -D_FORTIFY_SOURCE=2 -Wl,-z,relro,-z,now -fPIE -fpie -pie"
 LDFLAGS="-z relro -z now"
 
 AC_ARG_ENABLE([debug], AS_HELP_STRING([--enable-debug],[Enable debug @<:@default=false@:>@]),
diff --git a/src/usb_moded-appsync.c b/src/usb_moded-appsync.c
index eac7a77..4c82b2b 100644
--- a/src/usb_moded-appsync.c
+++ b/src/usb_moded-appsync.c
@@ -52,7 +52,7 @@ static void cancel_enumerate_usb_timer(void);
 static GList *sync_list = NULL;
 
 static guint enumerate_usb_id = 0;
-static struct timeval sync_tv;
+static struct timeval sync_tv = {0, 0};
 #ifdef APP_SYNC_DBUS
 static  int no_dbus = 0;
 #else
diff --git a/src/usb_moded-appsync.h b/src/usb_moded-appsync.h
index f1ef638..0234957 100644
--- a/src/usb_moded-appsync.h
+++ b/src/usb_moded-appsync.h
@@ -32,6 +32,8 @@
 #define APP_INFO_SYSTEMD_KEY	"systemd"
 #define APP_INFO_POST		"post"
 
+/** Application activation state
+ */
 typedef enum {
   /** Application is not relevant for the current mode */
   APP_STATE_DONTCARE = 0,
@@ -46,15 +48,13 @@ typedef enum {
  */
 typedef struct list_elem
 {
-  /*@{*/
-  char *name;		/* name of the app to launch */
-  char *mode; 		/* mode in which to launch the app */
-  char *launch;		/* dbus launch command/address */ 
-  app_state_t state;	/* marker to check if the app has started sucessfully */
-  int systemd;		/* marker to know if we start it with systemd or not */
-  int post;		/* marker to indicate when to start the app */
-  /*@}*/
-}list_elem;
+  char *name;           /**< name of the app to launch */
+  char *mode;           /**< mode in which to launch the app */
+  char *launch;         /**< dbus launch command/address */
+  app_state_t state;    /**< marker to check if the app has started sucessfully */
+  int systemd;          /**< marker to know if we start it with systemd or not */
+  int post;             /**< marker to indicate when to start the app */
+} list_elem;
 
 void readlist(int diag);
 int activate_sync(const char *mode);
diff --git a/src/usb_moded-config.c b/src/usb_moded-config.c
index d6c0513..26a74e5 100644
--- a/src/usb_moded-config.c
+++ b/src/usb_moded-config.c
@@ -528,7 +528,12 @@ set_config_result_t set_mode_whitelist(const char *whitelist)
     g_free(mode_setting);
 
     current_mode = get_usb_mode();
-    if (strcmp(current_mode, MODE_CHARGING_FALLBACK) && strcmp(current_mode, MODE_ASK) && valid_mode(current_mode)) {
+    if (!strcmp(current_mode, MODE_UNDEFINED)) {
+      /* Disconnected -> do nothing */
+    }
+    else if (strcmp(current_mode, MODE_CHARGING_FALLBACK) && strcmp(current_mode, MODE_ASK) && valid_mode(current_mode)) {
+      /* Invalid mode that is not MODE_ASK or MODE_CHARGING_FALLBACK
+       * -> switch to MODE_CHARGING_FALLBACK */
       usb_moded_mode_cleanup(get_usb_module());
       set_usb_mode(MODE_CHARGING_FALLBACK);
     }
diff --git a/src/usb_moded-config.h b/src/usb_moded-config.h
index 3570bc0..c6ed11d 100644
--- a/src/usb_moded-config.h
+++ b/src/usb_moded-config.h
@@ -85,10 +85,12 @@ char * get_mode_whitelist(void);
 
 int is_roaming_not_allowed(void);
 
+/** Configuration change result
+ */
 typedef enum set_config_result_t {
-	SET_CONFIG_ERROR = -1,
-	SET_CONFIG_UPDATED,
-	SET_CONFIG_UNCHANGED
+    SET_CONFIG_ERROR = -1,  /**< Value change failed */
+    SET_CONFIG_UPDATED,     /**< Value change succeeded */
+    SET_CONFIG_UNCHANGED,   /**< Value did not change */
 } set_config_result_t;
 
 int conf_file_merge(void);
diff --git a/src/usb_moded-dbus.c b/src/usb_moded-dbus.c
index 3a2e685..0c8caec 100644
--- a/src/usb_moded-dbus.c
+++ b/src/usb_moded-dbus.c
@@ -47,8 +47,6 @@
 static DBusConnection *dbus_connection_sys = NULL;
 static gboolean        have_service_name   = FALSE;
 
-extern gboolean rescue_mode;
-
 /**
  * Issues "sig_usb_config_ind" signal.
 */
@@ -188,6 +186,11 @@ static DBusHandlerResult msg_handler(DBusConnection *const connection, DBusMessa
 
   if(!interface || !member || !object) goto EXIT;
 
+  log_debug("DBUS %s %s.%s from %s",
+            dbus_message_type_to_string(type),
+            interface, member,
+            dbus_message_get_sender(msg) ?: "N/A");
+
   if( type == DBUS_MESSAGE_TYPE_SIGNAL )
   {
 	if( !strcmp(interface, INIT_DONE_INTERFACE) && !strcmp(member, INIT_DONE_SIGNAL) ) {
diff --git a/src/usb_moded-dyn-config.h b/src/usb_moded-dyn-config.h
index 81e7d2d..aa9ab96 100644
--- a/src/usb_moded-dyn-config.h
+++ b/src/usb_moded-dyn-config.h
@@ -65,36 +65,34 @@ android engineers prefered to have sysfs entries... go figure... */
  */
 typedef struct mode_list_elem
 {
-  /*@{ */
-  char *mode_name;			/* mode name */
-  char *mode_module;			/* needed module for given mode */
-  int appsync;				/* requires appsync or not */
-  int network;				/* bring up network or not */
-  int mass_storage;			/* Use mass-storage functions */
-  char *network_interface;		/* Which network interface to bring up if network needs to be enabled */
-  char *sysfs_path;			/* path to set sysfs options */
-  char *sysfs_value;			/* option name/value to write to sysfs */
-  char *sysfs_reset_value;		/* value to reset the the sysfs to default */
-  char *softconnect;			/* value to be written to softconnect interface */
-  char *softconnect_disconnect;		/* value to set on the softconnect interface to disable after disconnect */
-  char *softconnect_path;		/* path for the softconnect */
-  char *android_extra_sysfs_path;	/* path for static value that never changes that needs to be set by sysfs :( */
-  char *android_extra_sysfs_value;	/* static value that never changes that needs to be set by sysfs :( */
-  char *android_extra_sysfs_path2;	/* path for static value that never changes that needs to be set by sysfs :( */
-  char *android_extra_sysfs_value2;	/* static value that never changes that needs to be set by sysfs :( */
-  char *android_extra_sysfs_path3;	/* path for static value that never changes that needs to be set by sysfs :( */
-  char *android_extra_sysfs_value3;	/* static value that never changes that needs to be set by sysfs :( */
-  char *android_extra_sysfs_path4;	/* path for static value that never changes that needs to be set by sysfs :( */
-  char *android_extra_sysfs_value4;	/* static value that never changes that needs to be set by sysfs :( */
-  char *idProduct;			/* product id to assign to a specific profile */
-  char *idVendorOverride;		/* Temporary vendor override for special modes used by odms in testing/manufacturing */
-  int nat;				/* If NAT should be set up in this mode or not */
-  int dhcp_server;			/* if a DHCP server needs to be configured and started or not */
+  char *mode_name;                      /**< Mode name */
+  char *mode_module;                    /**< Needed module for given mode */
+  int appsync;                          /**< Requires appsync or not */
+  int network;                          /**< Bring up network or not */
+  int mass_storage;                     /**< Use mass-storage functions */
+  char *network_interface;              /**< Which network interface to bring up if network needs to be enabled */
+  char *sysfs_path;                     /**< Path to set sysfs options */
+  char *sysfs_value;                    /**< Option name/value to write to sysfs */
+  char *sysfs_reset_value;              /**< Value to reset the the sysfs to default */
+  char *softconnect;                    /**< Value to be written to softconnect interface */
+  char *softconnect_disconnect;         /**< Value to set on the softconnect interface to disable after disconnect */
+  char *softconnect_path;               /**< Path for the softconnect */
+  char *android_extra_sysfs_path;       /**< Path for static value that never changes that needs to be set by sysfs :( */
+  char *android_extra_sysfs_value;      /**< Static value that never changes that needs to be set by sysfs :( */
+  char *android_extra_sysfs_path2;      /**< Path for static value that never changes that needs to be set by sysfs :( */
+  char *android_extra_sysfs_value2;     /**< Static value that never changes that needs to be set by sysfs :( */
+  char *android_extra_sysfs_path3;      /**< Path for static value that never changes that needs to be set by sysfs :( */
+  char *android_extra_sysfs_value3;     /**< Static value that never changes that needs to be set by sysfs :( */
+  char *android_extra_sysfs_path4;      /**< Path for static value that never changes that needs to be set by sysfs :( */
+  char *android_extra_sysfs_value4;     /**< Static value that never changes that needs to be set by sysfs :( */
+  char *idProduct;                      /**< Product id to assign to a specific profile */
+  char *idVendorOverride;               /**< Temporary vendor override for special modes used by odms in testing/manufacturing */
+  int nat;                              /**< If NAT should be set up in this mode or not */
+  int dhcp_server;                      /**< if a DHCP server needs to be configured and started or not */
 #ifdef CONNMAN
-  char* connman_tethering;		/* connman's tethering technology path */
+  char* connman_tethering;              /**< Connman's tethering technology path */
 #endif
- /*@} */
-}mode_list_elem;
+} mode_list_elem;
 
 /* diag is used to select a secondary configuration location for diagnostic purposes */
 GList *read_mode_list(int diag);
diff --git a/src/usb_moded-log.c b/src/usb_moded-log.c
index 06084ee..5a19c8c 100644
--- a/src/usb_moded-log.c
+++ b/src/usb_moded-log.c
@@ -65,12 +65,14 @@ static void log_gettime(struct timeval *tv)
 	timersub(tv, &log_begtime, tv);
 }
 
-/**
- * Print the logged messages to the selected output
+/** Print the logged messages to the selected output
  *
- * @param lev The wanted log level
- * @param fmt The message to be logged
- * @param va The stdarg variable list
+ * @param file  Source file name
+ * @param func  Function name
+ * @param line  Line in source file
+ * @param lev   The wanted log level
+ * @param fmt   The message format string
+ * @param va    Arguments for the format string
  */
 void log_emit_va(const char *file, const char *func, int line, int lev, const char *fmt, va_list va)
 {
@@ -138,6 +140,15 @@ void log_emit_va(const char *file, const char *func, int line, int lev, const ch
 	errno = saved;
 }
 
+/** Print the logged messages to the selected output
+ *
+ * @param file  Source file name
+ * @param func  Function name
+ * @param line  Line in source file
+ * @param lev   The wanted log level
+ * @param fmt   The message format string
+ * @param ...   Arguments for the format string
+ */
 void log_emit_real(const char *file, const char *func, int line, int lev, const char *fmt, ...)
 {
         va_list va;
diff --git a/src/usb_moded-modules-android.c b/src/usb_moded-modules-android.c
index 630af54..dc29bd2 100644
--- a/src/usb_moded-modules-android.c
+++ b/src/usb_moded-modules-android.c
@@ -38,9 +38,6 @@
 #include "usb_moded-config.h"
 #include "usb_moded-modesetting.h"
 
-/* kmod context - initialized at start in usb_moded_init */
-struct kmod_ctx *ctx;
-
 /** load module 
  *
  * @param module Name of the module to load
diff --git a/src/usb_moded-network.c b/src/usb_moded-network.c
index 0b6f50d..72e2d82 100644
--- a/src/usb_moded-network.c
+++ b/src/usb_moded-network.c
@@ -52,7 +52,7 @@
 #define UDHCP_CONFIG_DIR	"/run/usb-moded"
 #define UDHCP_CONFIG_LINK	"/etc/udhcpd.conf"
 
-const char default_interface[] = "usb0";
+static const char default_interface[] = "usb0";
 
 /** IP forwarding configuration block */
 typedef struct ipforward_data
@@ -100,6 +100,8 @@ static int check_interface(char *interface)
 
 static char* get_interface(struct mode_list_elem *data)
 {
+  (void)data; // FIXME: why is this passed in the 1st place?
+
   char *interface = 0;
   char *setting   = get_network_setting(NETWORK_INTERFACE_KEY);
 
diff --git a/src/usb_moded-trigger.c b/src/usb_moded-trigger.c
index e09f346..8ad73fe 100644
--- a/src/usb_moded-trigger.c
+++ b/src/usb_moded-trigger.c
@@ -47,7 +47,7 @@ static struct udev *udev = 0;
 static struct udev_monitor *mon = 0;
 static GIOChannel *iochannel = 0;
 static guint watch_id = 0;
-static const char *dev_name;
+static const char *dev_name = 0;
 
 /* static function definitions */
 static gboolean monitor_udev(GIOChannel *iochannel G_GNUC_UNUSED, GIOCondition cond,
@@ -56,6 +56,8 @@ static void udev_parse(struct udev_device *dev);
 
 static void notify_issue (gpointer data)
 {
+	(void)data;
+
         log_debug("trigger watch destroyed\n!");
 	/* clean up & restart trigger */
 	trigger_stop();
diff --git a/src/usb_moded-udev.c b/src/usb_moded-udev.c
index 7d86cd3..1e39b7f 100644
--- a/src/usb_moded-udev.c
+++ b/src/usb_moded-udev.c
@@ -40,10 +40,10 @@
 #include "usb_moded-modes.h"
 
 /* global variables */
-static struct udev *udev;
-static struct udev_monitor *mon;
-static GIOChannel *iochannel;
-static guint watch_id; 
+static struct udev *udev = 0;
+static struct udev_monitor *mon = 0;
+static GIOChannel *iochannel = 0;
+static guint watch_id = 0;
 static char *dev_name = 0;
 static int cleanup = 0;
 /* track cable and charger connects disconnects */
@@ -70,6 +70,8 @@ static gboolean cable_connection_timeout_cb(gpointer data);
 
 static void notify_issue (gpointer data)
 {
+	(void)data;
+
 	/* we do not want to restart when we try to clean up */
 	if(cleanup)
 		return;
@@ -335,6 +337,8 @@ static void setup_charger_connection(void)
 
 static gboolean cable_connection_timeout_cb(gpointer data)
 {
+	(void)data;
+
 	log_debug("connect delay: timeout");
 	cable_connection_timeout_id = 0;
 
diff --git a/src/usb_moded-util.c b/src/usb_moded-util.c
index f716fdf..2007f78 100644
--- a/src/usb_moded-util.c
+++ b/src/usb_moded-util.c
@@ -29,8 +29,7 @@
 
 #include "usb_moded-dbus.h"
 
-DBusError       error;
-DBusConnection *conn = 0;
+static DBusConnection *conn = 0;
 
 static int query_mode (void)
 {
@@ -408,7 +407,7 @@ int main (int argc, char *argv[])
    }
 
   /* init dbus */
-  dbus_error_init(&error);
+  DBusError error = DBUS_ERROR_INIT;
 
   conn = dbus_bus_get_private(DBUS_BUS_SYSTEM, &error);
   if (!conn)
diff --git a/src/usb_moded.c b/src/usb_moded.c
index 9d9b96b..2064d95 100644
--- a/src/usb_moded.c
+++ b/src/usb_moded.c
@@ -65,17 +65,29 @@
 # define VERBOSE_WAKELOCKING 0
 #endif
 
+/** A struct containing all the usb_moded info needed
+ */
+typedef struct usb_mode
+{
+  gboolean connected;           /**< Connection status, 1 for connected */
+  gboolean mounted;             /**< Mount status, 1 for mounted -UNUSED atm- */
+  gboolean android_usb_broken;  /**< Used to keep an active gadget for broken Android kernels */
+  char *mode;                   /**< The mode name */
+  char *module;                 /**< The module name for the specific mode */
+  struct mode_list_elem *data;  /**< Contains the mode data */
+} usb_mode;
+
 /* global definitions */
 
 static int usb_moded_exitcode = EXIT_FAILURE;
 static GMainLoop *usb_moded_mainloop = NULL;
 
 gboolean rescue_mode = FALSE;
-gboolean diag_mode = FALSE;
-gboolean hw_fallback = FALSE;
-gboolean android_broken_usb = FALSE;
-gboolean android_ignore_udev_events = FALSE;
-gboolean android_ignore_next_udev_disconnect_event = FALSE;
+static gboolean diag_mode = FALSE;
+static gboolean hw_fallback = FALSE;
+static gboolean android_broken_usb = FALSE;
+static gboolean android_ignore_udev_events = FALSE;
+static gboolean android_ignore_next_udev_disconnect_event = FALSE;
 #ifdef SYSTEMD
 static gboolean systemd_notify = FALSE;
 #endif
@@ -120,9 +132,17 @@ static void set_cable_connection_delay(int delay_ms)
 	}
 }
 
-struct usb_mode current_mode;
-guint charging_timeout = 0;
-static GList *modelist;
+static struct usb_mode current_mode = {
+    .connected = FALSE,
+    .mounted = FALSE,
+    .android_usb_broken = FALSE,
+    .mode = NULL,
+    .module = NULL,
+    .data = NULL,
+};
+
+static guint charging_timeout = 0;
+static GList *modelist = 0;
 
 /* static helper functions */
 static gboolean set_disconnected(gpointer data);
@@ -186,6 +206,8 @@ void set_usb_connected(gboolean connected)
 
 static gboolean set_disconnected(gpointer data)
 {
+  (void)data;
+
   /* let usb settle */
   usb_moded_sleep(1);
   /* only disconnect for real if we are actually still disconnected */
@@ -209,6 +231,8 @@ static gboolean set_disconnected(gpointer data)
 /* set disconnected without sending signals. */
 static gboolean set_disconnected_silent(gpointer data)
 {
+  (void)data;
+
 if(!get_usb_connection_state())
         {
                 log_debug("Resetting connection data after HUP\n");
@@ -767,6 +791,10 @@ static void usb_moded_cleanup(void)
 /* charging fallback handler */
 static gboolean charging_fallback(gpointer data)
 {
+  (void)data;
+
+  charging_timeout = 0;
+
   /* if a mode has been set we don't want it changed to charging
    * after 5 seconds. We set it to ask, so anything different 
    * means a mode has been set */
@@ -780,7 +808,6 @@ static gboolean charging_fallback(gpointer data)
   free(current_mode.mode);
   current_mode.mode = strdup(MODE_ASK);
   current_mode.data = NULL;
-  charging_timeout = 0;
   log_info("Falling back on charging mode.\n");
 	
   return(FALSE);
@@ -1352,8 +1379,12 @@ int main(int argc, char* argv[])
 	/* silence usb_moded_system() calls */
 	if( log_get_type() != LOG_TO_STDERR && log_get_level() != LOG_DEBUG )
 	{
-		freopen("/dev/null", "a", stdout);
-		freopen("/dev/null", "a", stderr);
+		if( !freopen("/dev/null", "a", stdout) ) {
+			log_err("can't redirect stdout: %m");
+		}
+		if( !freopen("/dev/null", "a", stderr) ) {
+			log_err("can't redirect stderr: %m");
+		}
 	}
 
 #if !GLIB_CHECK_VERSION(2, 36, 0)
diff --git a/src/usb_moded.h b/src/usb_moded.h
index e4912b7..f16df5f 100644
--- a/src/usb_moded.h
+++ b/src/usb_moded.h
@@ -43,23 +43,12 @@
 #define USB_MODED_LOCKFILE	"/var/run/usb_moded.pid"
 #define MAX_READ_BUF 512
 
-/** 
- * a struct containing all the usb_moded info needed 
+/** Mode list types
  */
-typedef struct usb_mode  
-{
-  /*@{*/
-  gboolean connected; 		/* connection status, 1 for connected */
-  gboolean mounted;  		/* mount status, 1 for mounted -UNUSED atm- */
-  gboolean android_usb_broken;  /* Used to keep an active gadget for broken Android kernels */
-  char *mode;  			/* the mode name */
-  char *module; 		/* the module name for the specific mode */
-  struct mode_list_elem *data;  /* contains the mode data */
-  /*@}*/
-}usb_mode;
-
 typedef enum mode_list_type_t {
+    /** All configured modes */
     SUPPORTED_MODES_LIST,
+    /** Configured modes that can be activated */
     AVAILABLE_MODES_LIST
 } mode_list_type_t;
 
@@ -99,6 +88,7 @@ void allow_suspend(void);
 void delay_suspend(void);
 
 extern int cable_connection_delay;
+extern gboolean rescue_mode;
 
 void usb_moded_stop(int exitcode);