NetworkManager/src/libnm-core-impl/nm-dbus-utils.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2015 Red Hat, Inc.
 */

#include "libnm-core-impl/nm-default-libnm-core.h"

#include "libnm-core-intern/nm-core-internal.h"

typedef struct {
    char               *signal_name;
    const GVariantType *signature;
} NMDBusSignalData;

static void
dbus_signal_data_free(gpointer data, GClosure *closure)
{
    NMDBusSignalData *sd = data;

    g_free(sd->signal_name);
    g_slice_free(NMDBusSignalData, sd);
}

static void
dbus_signal_meta_marshal(GClosure     *closure,
                         GValue       *return_value,
                         guint         n_param_values,
                         const GValue *param_values,
                         gpointer      invocation_hint,
                         gpointer      marshal_data)
{
    NMDBusSignalData *sd = marshal_data;
    const char       *signal_name;
    GVariant         *parameters, *param;
    GValue           *closure_params;
    gsize             n_params, i;

    g_return_if_fail(n_param_values == 4);

    signal_name = g_value_get_string(&param_values[2]);
    parameters  = g_value_get_variant(&param_values[3]);

    if (strcmp(signal_name, sd->signal_name) != 0)
        return;

    if (sd->signature) {
        if (!g_variant_is_of_type(parameters, sd->signature)) {
            g_warning("%p: got signal '%s' but parameters were of type '%s', not '%s'",
                      g_value_get_object(&param_values[0]),
                      signal_name,
                      g_variant_get_type_string(parameters),
                      g_variant_type_peek_string(sd->signature));
            return;
        }

        n_params = g_variant_n_children(parameters) + 1;
    } else
        n_params = 1;

    closure_params = g_new0(GValue, n_params);
    g_value_init(&closure_params[0], G_TYPE_OBJECT);
    g_value_copy(&param_values[0], &closure_params[0]);

    for (i = 1; i < n_params; i++) {
        param = g_variant_get_child_value(parameters, i - 1);
        if (g_variant_is_of_type(param, G_VARIANT_TYPE("ay"))
            || g_variant_is_of_type(param, G_VARIANT_TYPE("aay"))) {
            /* g_dbus_gvariant_to_gvalue() thinks 'ay' means "non-UTF-8 NUL-terminated string" */
            g_value_init(&closure_params[i], G_TYPE_VARIANT);
            g_value_set_variant(&closure_params[i], param);
        } else
            g_dbus_gvariant_to_gvalue(param, &closure_params[i]);
        g_variant_unref(param);
    }

    g_cclosure_marshal_generic(closure, NULL, n_params, closure_params, invocation_hint, NULL);

    for (i = 0; i < n_params; i++)
        g_value_unset(&closure_params[i]);
    g_free(closure_params);
}

/**
 * _nm_dbus_signal_connect_data:
 * @proxy: a #GDBusProxy
 * @signal_name: the D-Bus signal to connect to
 * @signature: (allow-none): the signal's type signature (must be a tuple)
 * @c_handler: the signal handler function
 * @data: (allow-none): data to pass to @c_handler
 * @destroy_data: (allow-none): closure destroy notify for @data
 * @connect_flags: connection flags
 *
 * Connects to the D-Bus signal @signal_name on @proxy. @c_handler must be a
 * void function whose first argument is a #GDBusProxy, followed by arguments
 * for each element of @signature, ending with a #gpointer argument for @data.
 *
 * The argument types in @c_handler correspond to the types output by
 * g_dbus_gvariant_to_gvalue(), except for 'ay' and 'aay'. In particular:
 * - both 16-bit and 32-bit integers are passed as #int/#guint
 * - 'as' values are passed as #GStrv (char **)
 * - all other array, tuple, and dict types are passed as #GVariant
 *
 * If @signature is %NULL, then the signal's parameters will be ignored, and
 * @c_handler should take only the #GDBusProxy and #gpointer arguments.
 *
 * Returns: the signal handler ID, which can be used with
 *   g_signal_handler_remove(). Beware that because of the way the signal is
 *   connected, you will not be able to remove it with
 *   g_signal_handlers_disconnect_by_func(), although
 *   g_signal_handlers_disconnect_by_data() will work correctly.
 */
gulong
_nm_dbus_signal_connect_data(GDBusProxy         *proxy,
                             const char         *signal_name,
                             const GVariantType *signature,
                             GCallback           c_handler,
                             gpointer            data,
                             GClosureNotify      destroy_data,
                             GConnectFlags       connect_flags)
{
    NMDBusSignalData *sd;
    GClosure         *closure;
    gboolean          swapped = !!(connect_flags & G_CONNECT_SWAPPED);
    gboolean          after   = !!(connect_flags & G_CONNECT_AFTER);

    g_return_val_if_fail(G_IS_DBUS_PROXY(proxy), 0);
    g_return_val_if_fail(signal_name != NULL, 0);
    g_return_val_if_fail(signature == NULL || g_variant_type_is_tuple(signature), 0);
    g_return_val_if_fail(c_handler != NULL, 0);

    sd              = g_slice_new(NMDBusSignalData);
    sd->signal_name = g_strdup(signal_name);
    sd->signature   = signature;

    closure = (swapped ? g_cclosure_new_swap : g_cclosure_new)(c_handler, data, destroy_data);
    g_closure_set_marshal(closure, g_cclosure_marshal_generic);
    g_closure_set_meta_marshal(closure, sd, dbus_signal_meta_marshal);
    g_closure_add_finalize_notifier(closure, sd, dbus_signal_data_free);

    return g_signal_connect_closure(proxy, "g-signal", closure, after);
}

/**
 * _nm_dbus_signal_connect:
 * @proxy: a #GDBusProxy
 * @signal_name: the D-Bus signal to connect to
 * @signature: the signal's type signature (must be a tuple)
 * @c_handler: the signal handler function
 * @data: (allow-none): data to pass to @c_handler
 *
 * Simplified version of _nm_dbus_signal_connect_data() with fewer arguments.
 *
 * Returns: the signal handler ID, as with _nm_signal_connect_data().
 */

/**
 * _nm_dbus_typecheck_response:
 * @response: the #GVariant response to check.
 * @reply_type: the expected reply type. It may be %NULL to perform no
 *   checking.
 * @error: (allow-none): the error in case the @reply_type does not match.
 *
 * Returns: %TRUE, if @response is of the expected @reply_type.
 */
gboolean
_nm_dbus_typecheck_response(GVariant *response, const GVariantType *reply_type, GError **error)
{
    g_return_val_if_fail(response, FALSE);

    if (!reply_type)
        return TRUE;
    if (g_variant_is_of_type(response, reply_type))
        return TRUE;

    /* This is the same error code that g_dbus_connection_call() returns if
     * @reply_type doesn't match.
     */
    g_set_error(error,
                G_IO_ERROR,
                G_IO_ERROR_INVALID_ARGUMENT,
                _("Method returned type '%s', but expected '%s'"),
                g_variant_get_type_string(response),
                g_variant_type_peek_string(reply_type));
    return FALSE;
}

/**
 * _nm_dbus_proxy_call_finish:
 * @proxy: A #GDBusProxy.
 * @res: A #GAsyncResult obtained from the #GAsyncReadyCallback passed to
 *   g_dbus_proxy_call().
 * @reply_type: (allow-none): the expected type of the reply, or %NULL
 * @error: Return location for error or %NULL.
 *
 * Finishes an operation started with g_dbus_proxy_call(), as with
 * g_dbus_proxy_call_finish(), except thatif @reply_type is non-%NULL, then it
 * will also check that the response matches that type signature, and return
 * an error if not.
 *
 * Returns: %NULL if @error is set. Otherwise, a #GVariant tuple with
 * return values. Free with g_variant_unref().
 */
GVariant *
_nm_dbus_proxy_call_finish(GDBusProxy         *proxy,
                           GAsyncResult       *res,
                           const GVariantType *reply_type,
                           GError            **error)
{
    GVariant *variant;

    variant = g_dbus_proxy_call_finish(proxy, res, error);
    if (variant && !_nm_dbus_typecheck_response(variant, reply_type, error))
        nm_clear_pointer(&variant, g_variant_unref);
    return variant;
}

GVariant *
_nm_dbus_connection_call_finish(GDBusConnection    *dbus_connection,
                                GAsyncResult       *result,
                                const GVariantType *reply_type,
                                GError            **error)
{
    GVariant *variant;

    variant = g_dbus_connection_call_finish(dbus_connection, result, error);
    if (variant && !_nm_dbus_typecheck_response(variant, reply_type, error))
        nm_clear_pointer(&variant, g_variant_unref);
    return variant;
}

/**
 * _nm_dbus_error_has_name:
 * @error: (allow-none): a #GError, or %NULL
 * @dbus_error_name: a D-Bus error name
 *
 * Checks if @error is set and corresponds to the D-Bus error @dbus_error_name.
 *
 * This should only be used for "foreign" D-Bus errors (eg, errors
 * from BlueZ or wpa_supplicant). All NetworkManager D-Bus errors
 * should be properly mapped by gdbus to one of the domains/codes in
 * nm-errors.h.
 *
 * Returns: %TRUE or %FALSE
 */
gboolean
_nm_dbus_error_has_name(GError *error, const char *dbus_error_name)
{
    gboolean has_name = FALSE;

    if (error && g_dbus_error_is_remote_error(error)) {
        char *error_name;

        error_name = g_dbus_error_get_remote_error(error);
        has_name   = !g_strcmp0(error_name, dbus_error_name);
        g_free(error_name);
    }

    return has_name;
}