[ssu] Use ssusysinfo instead of SSU D-Bus interface

During bootup usb-moded needs device name / model information before
the system has reached a point where SSU daemon can be started. This
can cause systemd deadlocks and/or timeouts as usb-moded waits for SSU
daemon and the rest of the bootup is blocked until usb-moded reaches
ready state.

Use ssu-sysinfo C-library that can provide the device details required
by usb-moded without using any IPC mechanisms.
Signed-off-by: Simo Piiroinen <simo.piiroinen@jollamobile.com>

configure.ac

@@ -97,6 +97,7 @@ PKG_CHECK_MODULES([USB_MODED], [
  gio-2.0
  libudev
  libkmod
+ ssu-sysinfo
 ])
 
 AC_SUBST(USB_MODED_LIBS)

rpm/usb-moded.spec

@@ -15,6 +15,7 @@ BuildRequires: pkgconfig(udev)
 BuildRequires: pkgconfig(libkmod)
 BuildRequires: doxygen
 BuildRequires: pkgconfig(libsystemd-daemon)
+BuildRequires: pkgconfig(ssu-sysinfo)
 
 Requires: lsof
 Requires: usb-moded-configs

src/usb_moded-ssu.c

@@ -21,129 +21,43 @@
 */
 
 #include <glib.h>
-
-#include <dbus/dbus.h>
-
+#include <ssusysinfo.h>
 #include "usb_moded-ssu.h"
 #include "usb_moded-log.h"
-#include "usb_moded-dbus-private.h"
-
-/** SSU D-Bus service name */
-#define SSU_DBUS_SERVICE          "org.nemo.ssu"
 
-/** Default SSU D-Bus object path */
-#define SSU_DBUS_OBJECT           "/org/nemo/ssu"
+/** Cached ssu-sysinfo handle */
+static ssusysinfo_t *ssu_instance = 0;
 
-/** SSU D-Bus interface */
-#define SSU_DBUS_INTERFACE        "org.nemo.ssu"
+/** Flag for ssu-sysinfo instance has been initialized */
+static gboolean      ssu_intialized = FALSE;
 
-/** SSU displayName D-Bus method call */
-#define SSU_DBUS_GET_DISPLAY_NAME "displayName"
-
-/** SsuDisplayType enum adapted from ssu c++ headers */
-typedef enum
+/** Atexit callback for releasing cached ssu-sysinfo handle */
+static void ssu_free_handle(void)
 {
-	/** Manufacturer, like ACME Corp.
-	 *  Board mappings key "deviceManufacturer" */
-	SsuDeviceManufacturer = 0,
-
-	/** Marketed device name, like Pogoblaster 3000.
-	 *  Board mappings key "prettyModel" */
-	SsuDeviceModel        = 1,
+    /* Make sure instance does not get created on exit path */
+    ssu_intialized = TRUE;
 
-	/** Type designation, like NCC-1701.
-	 *  Beard mappings key "deviceDesignation" */
-	SsuDeviceDesignation  = 2,
-} SsuDisplayType;
+    /* Release existing instance */
+    ssusysinfo_delete(ssu_instance),
+        ssu_instance = 0;
+}
 
-/** Wrapper for making synchronous org.nemo.ssu.displayName() method calls
+/** Helper for obtaining ssu-sysinfo handle on demand
  *
- * Caller must release non-null return value with g_free().
- *
- * @param type_id display name type to query
- *
- * @return human readable string, or NULL in case of errors
+ * @return ssu-sysinfo, or NULL in case of errors
  */
-static gchar *
-usb_moded_get_ssu_display_name(SsuDisplayType type_id)
+static ssusysinfo_t *ssu_get_handle(void)
 {
-	gchar          *res = 0;
-	DBusConnection *con = 0;
-	DBusMessage    *req = 0;
-	DBusMessage    *rsp = 0;
-	dbus_int32_t    arg = type_id;
-	const char     *val = 0;
-	DBusError       err = DBUS_ERROR_INIT;
-
-	if( !(con = usb_moded_dbus_get_connection()) ) {
-		log_err("not connected to system bus");
-		goto EXIT;
-	}
-
-	req = dbus_message_new_method_call(SSU_DBUS_SERVICE,
-					   SSU_DBUS_OBJECT,
-					   SSU_DBUS_INTERFACE,
-					   SSU_DBUS_GET_DISPLAY_NAME);
-
-	if( !req ) {
-		log_err("could not create method call message");
-		goto EXIT;
-	}
-
-	if( !dbus_message_append_args(req,
-				      DBUS_TYPE_INT32, &arg,
-				      DBUS_TYPE_INVALID) ) {
-		log_err("could not add method call parameters");
-		goto EXIT;
-	}
-
-	rsp = dbus_connection_send_with_reply_and_block(con, req, -1, &err);
-	if( !rsp ) {
-		/* Be less verbose with failures that are expected
-		 * if ssu service is not installed on the device. */
-		if( !strcmp(err.name, DBUS_ERROR_SERVICE_UNKNOWN) ) {
-			log_debug("%s D-Bus service is not available",
-				  SSU_DBUS_SERVICE);
-		}
-		else {
-			log_err("did not get reply: %s: %s",
-				err.name, err.message);
-		}
-		goto EXIT;
-	}
-
-	if( dbus_set_error_from_message(&err, rsp) ) {
-		log_err("got error reply: %s: %s", err.name, err.message);
-		goto EXIT;
-	}
-
-	if( !dbus_message_get_args(rsp, &err,
-				   DBUS_TYPE_STRING, &val,
-				   DBUS_TYPE_INVALID) ) {
-		log_err("could not parse reply: %s: %s",
-			err.name, err.message);
-		goto EXIT;
-	}
-
-	res = g_strdup(val);
-
-EXIT:
-
-	dbus_error_free(&err);
-
-	if( rsp )
-		dbus_message_unref(rsp);
-	if( req )
-		dbus_message_unref(req);
-	if( con )
-		dbus_connection_unref(con);
-
-	log_debug("ssu displayName(%d) -> %s", type_id, res ?: "N/A");
-
-	return res;
+    /* Attempt only once */
+    if( !ssu_intialized ) {
+        ssu_intialized = TRUE;
+        ssu_instance = ssusysinfo_create();
+        atexit(ssu_free_handle);
+    }
+    return ssu_instance;
 }
 
-/** Query device manufacturer name from the SSU D-Bus service
+/** Read device manufacturer name from the SSU configuration
  *
  * Caller must release non-null return value with g_free().
  *
@@ -152,10 +66,15 @@ EXIT:
 gchar *
 ssu_get_manufacturer_name(void)
 {
-	return usb_moded_get_ssu_display_name(SsuDeviceManufacturer);
+    gchar *res = 0;
+    const char *val = ssusysinfo_device_manufacturer(ssu_get_handle());
+    if( val && strcmp(val, "UNKNOWN") )
+        res = g_strdup(val);
+    log_debug("%s() -> %s", __FUNCTION__, res ?: "N/A");
+    return res;
 }
 
-/** Query device model name from the SSU D-Bus service
+/** Read device model name from the SSU configuration
  *
  * Caller must release non-null return value with g_free().
  *
@@ -164,5 +83,10 @@ ssu_get_manufacturer_name(void)
 gchar *
 ssu_get_product_name(void)
 {
-	return usb_moded_get_ssu_display_name(SsuDeviceModel);
+    gchar *res = 0;
+    const char *val = ssusysinfo_device_pretty_name(ssu_get_handle());
+    if( val && strcmp(val, "UNKNOWN") )
+        res = g_strdup(val);
+    log_debug("%s() -> %s", __FUNCTION__, res ?: "N/A");
+    return res;
 }