dbus_common.c

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/*
 * wpa_supplicant D-Bus control interface - common functionality
 * Copyright (c) 2006, Dan Williams <dcbw@redhat.com> and Red Hat, Inc.
 * Copyright (c) 2009, Witold Sowa <witold.sowa@gmail.com>
 * Copyright (c) 2009, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "utils/includes.h"
#include <dbus/dbus.h>

#include "utils/common.h"
#include "utils/eloop.h"
#include "dbus_common.h"
#include "dbus_common_i.h"
#include "dbus_new.h"
#include "dbus_old.h"


#ifndef SIGPOLL
#ifdef SIGIO
/*
 * If we do not have SIGPOLL, try to use SIGIO instead. This is needed for
 * FreeBSD.
 */
#define SIGPOLL SIGIO
#endif
#endif


static void dispatch_data(DBusConnection *con)
{
        while (dbus_connection_get_dispatch_status(con) ==
               DBUS_DISPATCH_DATA_REMAINS)
                dbus_connection_dispatch(con);
}


static void dispatch_initial_dbus_messages(void *eloop_ctx, void *timeout_ctx)
{
        DBusConnection *con = eloop_ctx;
        dispatch_data(con);
}


static void process_watch(struct wpas_dbus_priv *priv,
                          DBusWatch *watch, eloop_event_type type)
{
        dbus_connection_ref(priv->con);

        priv->should_dispatch = 0;

        if (type == EVENT_TYPE_READ)
                dbus_watch_handle(watch, DBUS_WATCH_READABLE);
        else if (type == EVENT_TYPE_WRITE)
                dbus_watch_handle(watch, DBUS_WATCH_WRITABLE);
        else if (type == EVENT_TYPE_EXCEPTION)
                dbus_watch_handle(watch, DBUS_WATCH_ERROR);

        if (priv->should_dispatch) {
                dispatch_data(priv->con);
                priv->should_dispatch = 0;
        }

        dbus_connection_unref(priv->con);
}


static void process_watch_exception(int sock, void *eloop_ctx, void *sock_ctx)
{
        process_watch(eloop_ctx, sock_ctx, EVENT_TYPE_EXCEPTION);
}


static void process_watch_read(int sock, void *eloop_ctx, void *sock_ctx)
{
        process_watch(eloop_ctx, sock_ctx, EVENT_TYPE_READ);
}


static void process_watch_write(int sock, void *eloop_ctx, void *sock_ctx)
{
        process_watch(eloop_ctx, sock_ctx, EVENT_TYPE_WRITE);
}


static dbus_bool_t add_watch(DBusWatch *watch, void *data)
{
        struct wpas_dbus_priv *priv = data;
        unsigned int flags;
        int fd;

        if (!dbus_watch_get_enabled(watch))
                return TRUE;

        flags = dbus_watch_get_flags(watch);
        fd = dbus_watch_get_unix_fd(watch);

        eloop_register_sock(fd, EVENT_TYPE_EXCEPTION, process_watch_exception,
                            priv, watch);

        if (flags & DBUS_WATCH_READABLE) {
                eloop_register_sock(fd, EVENT_TYPE_READ, process_watch_read,
                                    priv, watch);
        }
        if (flags & DBUS_WATCH_WRITABLE) {
                eloop_register_sock(fd, EVENT_TYPE_WRITE, process_watch_write,
                                    priv, watch);
        }

        dbus_watch_set_data(watch, priv, NULL);

        return TRUE;
}


static void remove_watch(DBusWatch *watch, void *data)
{
        unsigned int flags;
        int fd;

        flags = dbus_watch_get_flags(watch);
        fd = dbus_watch_get_unix_fd(watch);

        eloop_unregister_sock(fd, EVENT_TYPE_EXCEPTION);

        if (flags & DBUS_WATCH_READABLE)
                eloop_unregister_sock(fd, EVENT_TYPE_READ);
        if (flags & DBUS_WATCH_WRITABLE)
                eloop_unregister_sock(fd, EVENT_TYPE_WRITE);

        dbus_watch_set_data(watch, NULL, NULL);
}


static void watch_toggled(DBusWatch *watch, void *data)
{
        if (dbus_watch_get_enabled(watch))
                add_watch(watch, data);
        else
                remove_watch(watch, data);
}


static void process_timeout(void *eloop_ctx, void *sock_ctx)
{
        DBusTimeout *timeout = sock_ctx;
        dbus_timeout_handle(timeout);
}


static dbus_bool_t add_timeout(DBusTimeout *timeout, void *data)
{
        struct wpas_dbus_priv *priv = data;
        if (!dbus_timeout_get_enabled(timeout))
                return TRUE;

        eloop_register_timeout(0, dbus_timeout_get_interval(timeout) * 1000,
                               process_timeout, priv, timeout);

        dbus_timeout_set_data(timeout, priv, NULL);

        return TRUE;
}


static void remove_timeout(DBusTimeout *timeout, void *data)
{
        struct wpas_dbus_priv *priv = data;
        eloop_cancel_timeout(process_timeout, priv, timeout);
        dbus_timeout_set_data(timeout, NULL, NULL);
}


static void timeout_toggled(DBusTimeout *timeout, void *data)
{
        if (dbus_timeout_get_enabled(timeout))
                add_timeout(timeout, data);
        else
                remove_timeout(timeout, data);
}


static void process_wakeup_main(int sig, void *signal_ctx)
{
        struct wpas_dbus_priv *priv = signal_ctx;

        if (sig != SIGPOLL || !priv->con)
                return;

        if (dbus_connection_get_dispatch_status(priv->con) !=
            DBUS_DISPATCH_DATA_REMAINS)
                return;

        /* Only dispatch once - we do not want to starve other events */
        dbus_connection_ref(priv->con);
        dbus_connection_dispatch(priv->con);
        dbus_connection_unref(priv->con);
}


static void wakeup_main(void *data)
{
        struct wpas_dbus_priv *priv = data;

        /* Use SIGPOLL to break out of the eloop select() */
        raise(SIGPOLL);
        priv->should_dispatch = 1;
}


static int integrate_with_eloop(struct wpas_dbus_priv *priv)
{
        if (!dbus_connection_set_watch_functions(priv->con, add_watch,
                                                 remove_watch, watch_toggled,
                                                 priv, NULL) ||
            !dbus_connection_set_timeout_functions(priv->con, add_timeout,
                                                   remove_timeout,
                                                   timeout_toggled, priv,
                                                   NULL)) {
                wpa_printf(MSG_ERROR, "dbus: Failed to set callback "
                           "functions");
                return -1;
        }

        if (eloop_register_signal(SIGPOLL, process_wakeup_main, priv))
                return -1;
        dbus_connection_set_wakeup_main_function(priv->con, wakeup_main,
                                                 priv, NULL);

        return 0;
}


static int wpas_dbus_init_common(struct wpas_dbus_priv *priv)
{
        DBusError error;
        int ret = 0;

        /* Get a reference to the system bus */
        dbus_error_init(&error);
        priv->con = dbus_bus_get(DBUS_BUS_SYSTEM, &error);
        if (!priv->con) {
                wpa_printf(MSG_ERROR, "dbus: Could not acquire the system "
                           "bus: %s - %s", error.name, error.message);
                ret = -1;
        }
        dbus_error_free(&error);

        return ret;
}


static int wpas_dbus_init_common_finish(struct wpas_dbus_priv *priv)
{
        /* Tell dbus about our mainloop integration functions */
        integrate_with_eloop(priv);

        /*
         * Dispatch initial DBus messages that may have come in since the bus
         * name was claimed above. Happens when clients are quick to notice the
         * service.
         *
         * FIXME: is there a better solution to this problem?
         */
        eloop_register_timeout(0, 50, dispatch_initial_dbus_messages,
                               priv->con, NULL);

        return 0;
}


static void wpas_dbus_deinit_common(struct wpas_dbus_priv *priv)
{
        if (priv->con) {
                eloop_cancel_timeout(dispatch_initial_dbus_messages,
                                     priv->con, NULL);
                dbus_connection_set_watch_functions(priv->con, NULL, NULL,
                                                    NULL, NULL, NULL);
                dbus_connection_set_timeout_functions(priv->con, NULL, NULL,
                                                      NULL, NULL, NULL);
                dbus_connection_unref(priv->con);
        }

        os_free(priv);
}


struct wpas_dbus_priv * wpas_dbus_init(struct wpa_global *global)
{
        struct wpas_dbus_priv *priv;

        priv = os_zalloc(sizeof(*priv));
        if (priv == NULL)
                return NULL;
        priv->global = global;

        if (wpas_dbus_init_common(priv) < 0) {
                wpas_dbus_deinit(priv);
                return NULL;
        }

#ifdef CONFIG_CTRL_IFACE_DBUS_NEW
        if (wpas_dbus_ctrl_iface_init(priv) < 0) {
                wpas_dbus_deinit(priv);
                return NULL;
        }
#endif /* CONFIG_CTRL_IFACE_DBUS_NEW */

#ifdef CONFIG_CTRL_IFACE_DBUS
        if (wpa_supplicant_dbus_ctrl_iface_init(priv) < 0) {
                wpas_dbus_deinit(priv);
                return NULL;
        }
#endif /* CONFIG_CTRL_IFACE_DBUS */

        if (wpas_dbus_init_common_finish(priv) < 0) {
                wpas_dbus_deinit(priv);
                return NULL;
        }

        return priv;
}


void wpas_dbus_deinit(struct wpas_dbus_priv *priv)
{
        if (priv == NULL)
                return;

#ifdef CONFIG_CTRL_IFACE_DBUS_NEW
        wpas_dbus_ctrl_iface_deinit(priv);
#endif /* CONFIG_CTRL_IFACE_DBUS_NEW */

#ifdef CONFIG_CTRL_IFACE_DBUS
        /* TODO: is any deinit needed? */
#endif /* CONFIG_CTRL_IFACE_DBUS */

        wpas_dbus_deinit_common(priv);
}