api,bearer: new 'ConnectionError' property

This new property will provide detailed information about the failed
connection attempt, or about the network initiated disconnection. The
property will be cleared only if a new connection attempt is
triggered, and so it can be used to investigate why a given attempt
failed without needing to be the one who triggered the attempt (e.g.
so that failures in NetworkManager-triggered connection attempts can
be investigated looking at the DBus API).

The property is built as a (ss) tuple, but the libmm-glib interface
provides methods to read this property as a GError.

cli/mmcli-bearer.c

@@ -133,10 +133,11 @@ mmcli_bearer_shutdown (void)
 static void
 print_bearer_info (MMBearer *bearer)
 {
-    MMBearerIpConfig   *ipv4_config;
+    g_autoptr(MMBearerIpConfig)    ipv4_config = NULL;
-    MMBearerIpConfig   *ipv6_config;
+    g_autoptr(MMBearerIpConfig)    ipv6_config = NULL;
-    MMBearerProperties *properties;
+    g_autoptr(MMBearerProperties)  properties = NULL;
-    MMBearerStats      *stats;
+    g_autoptr(MMBearerStats)       stats = NULL;
+    g_autoptr(GError)              connection_error = NULL;
     gint                           profile_id;
     gchar                         *profile_id_str;
 
@@ -145,6 +146,7 @@ print_bearer_info (MMBearer *bearer)
     properties       = mm_bearer_get_properties (bearer);
     stats            = mm_bearer_get_stats (bearer);
     profile_id       = mm_bearer_get_profile_id (bearer);
+    connection_error = mm_bearer_get_connection_error (bearer);
 
     profile_id_str = (profile_id != MM_3GPP_PROFILE_ID_UNKNOWN) ? g_strdup_printf ("%d", profile_id) : NULL;
 
@@ -152,6 +154,8 @@ print_bearer_info (MMBearer *bearer)
     mmcli_output_string      (MMC_F_BEARER_GENERAL_TYPE,      mm_bearer_type_get_string (mm_bearer_get_bearer_type (bearer)));
 
     mmcli_output_string      (MMC_F_BEARER_STATUS_CONNECTED,                mm_bearer_get_connected (bearer) ? "yes" : "no");
+    mmcli_output_string_take (MMC_F_BEARER_STATUS_CONNECTION_ERROR_NAME,    connection_error ? g_dbus_error_encode_gerror (connection_error) : NULL);
+    mmcli_output_string      (MMC_F_BEARER_STATUS_CONNECTION_ERROR_MESSAGE, connection_error ? connection_error->message : NULL);
     mmcli_output_string      (MMC_F_BEARER_STATUS_SUSPENDED,                mm_bearer_get_suspended (bearer) ? "yes" : "no");
     mmcli_output_string      (MMC_F_BEARER_STATUS_MULTIPLEXED,              mm_bearer_get_multiplexed (bearer) ? "yes" : "no");
     mmcli_output_string      (MMC_F_BEARER_STATUS_INTERFACE,                mm_bearer_get_interface (bearer));
@@ -315,11 +319,6 @@ print_bearer_info (MMBearer *bearer)
     }
 
     mmcli_output_dump ();
-
-    g_clear_object (&stats);
-    g_clear_object (&properties);
-    g_clear_object (&ipv4_config);
-    g_clear_object (&ipv6_config);
 }
 
 static void

cli/mmcli-output.c

@@ -210,6 +210,8 @@ static FieldInfo field_infos[] = {
     [MMC_F_BEARER_GENERAL_DBUS_PATH]               = { "bearer.dbus-path",                                "path",                     MMC_S_BEARER_GENERAL,             },
     [MMC_F_BEARER_GENERAL_TYPE]                    = { "bearer.type",                                     "type",                     MMC_S_BEARER_GENERAL,             },
     [MMC_F_BEARER_STATUS_CONNECTED]                = { "bearer.status.connected",                         "connected",                MMC_S_BEARER_STATUS,              },
+    [MMC_F_BEARER_STATUS_CONNECTION_ERROR_NAME]    = { "bearer.status.connection-error.name",             "connection error name",    MMC_S_BEARER_STATUS,              },
+    [MMC_F_BEARER_STATUS_CONNECTION_ERROR_MESSAGE] = { "bearer.status.connection-error.message",          "connection error message", MMC_S_BEARER_STATUS,              },
     [MMC_F_BEARER_STATUS_SUSPENDED]                = { "bearer.status.suspended",                         "suspended",                MMC_S_BEARER_STATUS,              },
     [MMC_F_BEARER_STATUS_MULTIPLEXED]              = { "bearer.status.multiplexed",                       "multiplexed",              MMC_S_BEARER_STATUS,              },
     [MMC_F_BEARER_STATUS_INTERFACE]                = { "bearer.status.interface",                         "interface",                MMC_S_BEARER_STATUS,              },

cli/mmcli-output.h

@@ -227,6 +227,8 @@ typedef enum {
     MMC_F_BEARER_GENERAL_TYPE,
     /* Bearer status section */
     MMC_F_BEARER_STATUS_CONNECTED,
+    MMC_F_BEARER_STATUS_CONNECTION_ERROR_NAME,
+    MMC_F_BEARER_STATUS_CONNECTION_ERROR_MESSAGE,
     MMC_F_BEARER_STATUS_SUSPENDED,
     MMC_F_BEARER_STATUS_MULTIPLEXED,
     MMC_F_BEARER_STATUS_INTERFACE,

docs/reference/libmm-glib/libmm-glib-sections.txt

@@ -1091,6 +1091,8 @@ mm_bearer_peek_properties
 mm_bearer_get_properties
 mm_bearer_peek_stats
 mm_bearer_get_stats
+mm_bearer_get_connection_error
+mm_bearer_peek_connection_error
 <SUBSECTION Methods>
 mm_bearer_connect
 mm_bearer_connect_finish
@@ -1835,6 +1837,8 @@ mm_gdbus_bearer_get_ip_timeout
 mm_gdbus_bearer_get_properties
 mm_gdbus_bearer_dup_properties
 mm_gdbus_bearer_get_connected
+mm_gdbus_bearer_get_connection_error
+mm_gdbus_bearer_dup_connection_error
 mm_gdbus_bearer_get_suspended
 mm_gdbus_bearer_get_multiplexed
 mm_gdbus_bearer_get_bearer_type
@@ -1851,6 +1855,7 @@ mm_gdbus_bearer_call_disconnect_sync
 <SUBSECTION Private>
 mm_gdbus_bearer_interface_info
 mm_gdbus_bearer_set_connected
+mm_gdbus_bearer_set_connection_error
 mm_gdbus_bearer_set_interface
 mm_gdbus_bearer_set_ip4_config
 mm_gdbus_bearer_set_ip6_config

introspection/org.freedesktop.ModemManager1.Bearer.xml

@@ -101,6 +101,20 @@
     -->
     <property name="Connected" type="b" access="read" />
 
+    <!--
+        ConnectionError:
+
+        Provides additional information specifying the reason why the modem is
+	not connected (either due to a failed connection attempt, or due to a
+	a network initiated disconnection).
+
+        The value is composed of two strings: the registered DBus error name,
+	and an optional error message.
+
+        Since: 1.18
+    -->
+    <property name="ConnectionError" type="(ss)" access="read" />
+
     <!--
         Suspended:
 

libmm-glib/mm-bearer.c

@@ -22,6 +22,7 @@
  */
 
 #include "mm-helpers.h"
+#include "mm-common-helpers.h"
 #include "mm-bearer.h"
 
 /**
@@ -58,6 +59,11 @@ struct _MMBearerPrivate {
     GMutex stats_mutex;
     guint stats_id;
     MMBearerStats *stats;
+
+    /* Connection error */
+    GMutex connection_error_mutex;
+    guint connection_error_id;
+    GError *connection_error;
 };
 
 /*****************************************************************************/
@@ -757,6 +763,116 @@ mm_bearer_peek_stats (MMBearer *self)
 
 /*****************************************************************************/
 
+static void
+connection_error_updated (MMBearer   *self,
+                          GParamSpec *pspec)
+{
+    g_mutex_lock (&self->priv->connection_error_mutex);
+    {
+        GVariant *tuple;
+
+        g_clear_error (&self->priv->connection_error);
+
+        tuple = mm_gdbus_bearer_get_connection_error (MM_GDBUS_BEARER (self));
+        if (tuple) {
+            g_autoptr(GError) error = NULL;
+
+            self->priv->connection_error = mm_common_error_from_tuple (tuple, &error);
+            if (error)
+                g_warning ("Invalid bearer connection error update received: %s", error->message);
+        }
+    }
+    g_mutex_unlock (&self->priv->connection_error_mutex);
+}
+
+static void
+ensure_internal_connection_error (MMBearer  *self,
+                                  GError   **dup)
+{
+    g_mutex_lock (&self->priv->connection_error_mutex);
+    {
+        /* If this is the first time ever asking for the object, setup the
+         * update listener and the initial object, if any. */
+        if (!self->priv->connection_error_id) {
+            g_autoptr(GVariant) tuple = NULL;
+
+            tuple = mm_gdbus_bearer_dup_connection_error (MM_GDBUS_BEARER (self));
+            if (tuple) {
+                g_autoptr(GError) error = NULL;
+
+                self->priv->connection_error = mm_common_error_from_tuple (tuple, &error);
+                if (error)
+                    g_warning ("Invalid bearer connection error: %s", error->message);
+            }
+
+            /* No need to clear this signal connection when freeing self */
+            self->priv->connection_error_id =
+                g_signal_connect (self,
+                                  "notify::connection-error",
+                                  G_CALLBACK (connection_error_updated),
+                                  NULL);
+        }
+
+        if (dup && self->priv->connection_error)
+            *dup = g_error_copy (self->priv->connection_error);
+    }
+    g_mutex_unlock (&self->priv->connection_error_mutex);
+}
+
+/**
+ * mm_bearer_get_connection_error:
+ * @self: A #MMBearer.
+ *
+ * Gets a #GError specifying the connection error details, if any.
+ *
+ * <warning>The values reported by @self are not updated when the values in the
+ * interface change. Instead, the client is expected to call
+ * mm_bearer_get_connection_error() again to get a new #GError with the
+ * new values.</warning>
+ *
+ * Returns: (transfer full): A #GError that must be freed with
+ * g_error_free() or %NULL if none.
+ *
+ * Since: 1.18
+ */
+GError *
+mm_bearer_get_connection_error (MMBearer *self)
+{
+    GError *error = NULL;
+
+    g_return_val_if_fail (MM_IS_BEARER (self), NULL);
+
+    ensure_internal_connection_error (self, &error);
+    return error;
+}
+
+/**
+ * mm_bearer_peek_connection_error:
+ * @self: A #MMBearer.
+ *
+ * Gets a #GError specifying the connection error details, if any.
+ *
+ * <warning>The returned value is only valid until the property changes so
+ * it is only safe to use this function on the thread where
+ * @self was constructed. Use mm_bearer_get_connection_error() if on another
+ * thread.</warning>
+ *
+ * Returns: (transfer none): A #GError, or %NULL if none. Do not
+ * free the returned value, it belongs to @self.
+ *
+ * Since: 1.18
+ */
+GError *
+mm_bearer_peek_connection_error (MMBearer *self)
+{
+    g_return_val_if_fail (MM_IS_BEARER (self), NULL);
+
+    ensure_internal_connection_error (self, NULL);
+    return self->priv->connection_error;
+}
+
+/*****************************************************************************/
+
 /**
  * mm_bearer_connect_finish:
  * @self: A #MMBearer.
@@ -932,6 +1048,7 @@ mm_bearer_init (MMBearer *self)
     g_mutex_init (&self->priv->ipv6_config_mutex);
     g_mutex_init (&self->priv->properties_mutex);
     g_mutex_init (&self->priv->stats_mutex);
+    g_mutex_init (&self->priv->connection_error_mutex);
 }
 
 static void
@@ -943,6 +1060,7 @@ finalize (GObject *object)
     g_mutex_clear (&self->priv->ipv6_config_mutex);
     g_mutex_clear (&self->priv->properties_mutex);
     g_mutex_clear (&self->priv->stats_mutex);
+    g_mutex_clear (&self->priv->connection_error_mutex);
 
     G_OBJECT_CLASS (mm_bearer_parent_class)->finalize (object);
 }
@@ -956,6 +1074,7 @@ dispose (GObject *object)
     g_clear_object (&self->priv->ipv6_config);
     g_clear_object (&self->priv->properties);
     g_clear_object (&self->priv->stats);
+    g_clear_error (&self->priv->connection_error);
 
     G_OBJECT_CLASS (mm_bearer_parent_class)->dispose (object);
 }

libmm-glib/mm-bearer.h

@@ -120,6 +120,9 @@ MMBearerIpConfig   *mm_bearer_peek_ipv6_config (MMBearer *self);
 MMBearerStats      *mm_bearer_get_stats        (MMBearer *self);
 MMBearerStats      *mm_bearer_peek_stats       (MMBearer *self);
 
+GError             *mm_bearer_get_connection_error  (MMBearer *self);
+GError             *mm_bearer_peek_connection_error (MMBearer *self);
+
 G_END_DECLS
 
 #endif /* _MM_BEARER_H_ */

libmm-glib/mm-common-helpers.c

@@ -1911,3 +1911,53 @@ mm_common_register_errors (void)
 
     return TRUE;
 }
+
+GError *
+mm_common_error_from_tuple (GVariant  *tuple,
+                            GError   **error)
+{
+    g_autoptr(GError)  dbus_error = NULL;
+    g_autofree gchar  *error_name = NULL;
+    g_autofree gchar  *error_message = NULL;
+
+    mm_common_register_errors ();
+
+    if (!g_variant_is_of_type (tuple, G_VARIANT_TYPE ("(ss)"))) {
+        g_set_error (error,
+                     MM_CORE_ERROR,
+                     MM_CORE_ERROR_INVALID_ARGS,
+                     "Cannot create error from tuple: "
+                     "invalid variant type received");
+        return NULL;
+    }
+
+    g_variant_get (tuple, "(ss)", &error_name, &error_message);
+    if (!error_name || !error_name[0])
+        return NULL;
+
+    /* We convert the error name into a proper GError (domain+code), but we
+     * don't attempt to give the error message to new_for_dbus_error() as that
+     * would generate a string we don't want (e.g. instead of just "Unknown
+     * Error" we would get "GDBus.Error:org.freedesktop.ModemManager1.Error.MobileEquipment.Unknown: Unknown error"
+     */
+    dbus_error = g_dbus_error_new_for_dbus_error (error_name, "");
+
+    /* And now we build a new GError with same domain+code but with the received
+     * error message */
+    return g_error_new (dbus_error->domain, dbus_error->code, "%s", error_message);
+}
+
+GVariant *
+mm_common_error_to_tuple (const GError *error)
+{
+    g_autofree gchar *error_name = NULL;
+    GVariant         *tuple[2];
+
+    mm_common_register_errors ();
+
+    error_name = g_dbus_error_encode_gerror (error);
+    tuple[0] = g_variant_new_string (error_name);
+    tuple[1] = g_variant_new_string (error->message);
+
+    return g_variant_ref_sink (g_variant_new_tuple (tuple, 2));
+}

libmm-glib/mm-common-helpers.h

@@ -203,5 +203,8 @@ gboolean  mm_utils_check_for_single_value (guint32 value);
 
 /* DBus error handling */
 gboolean  mm_common_register_errors  (void);
+GError   *mm_common_error_from_tuple (GVariant      *tuple,
+                                      GError       **error);
+GVariant *mm_common_error_to_tuple   (const GError  *error);
 
 #endif /* MM_COMMON_HELPERS_H */