path: root/server/sbus/sssd_dbus_connection.c

#include <sys/time.h>
#include "util/util.h"
#include "dbus/dbus.h"
#include "sbus/sssd_dbus.h"
#include "sbus/sssd_dbus_private.h"

/* Types */
struct dbus_ctx_list;

struct sbus_conn_ctx {
    DBusConnection *conn;
    struct tevent_context *ev;
    int connection_type;
    int disconnect;
    struct sbus_method_ctx *method_ctx_list;
    sbus_conn_destructor_fn destructor;
    void *pvt_data; /* Private data for this connection */
};

struct sbus_message_handler_ctx {
    struct sbus_conn_ctx *conn_ctx;
    struct sbus_method_ctx *method_ctx;
};

struct sbus_conn_watch_ctx {
    DBusWatch *watch;
    int fd;
    struct tevent_fd *fde;
    struct sbus_conn_ctx *top;
};

struct sbus_conn_timeout_ctx {
    DBusTimeout *timeout;
    struct tevent_timer *te;
    struct sbus_conn_ctx *top;
};

static int _method_list_contains_path(struct sbus_method_ctx *list,
                                      struct sbus_method_ctx *method);
static void sbus_unreg_object_paths(struct sbus_conn_ctx *dct_ctx);

static void sbus_dispatch(struct tevent_context *ev,
                               struct tevent_timer *te,
                               struct timeval tv, void *data)
{
    struct tevent_timer *new_event;
    struct sbus_conn_ctx *dct_ctx;
    DBusConnection *conn;
    int ret;

    if (data == NULL) return;

    dct_ctx = talloc_get_type(data, struct sbus_conn_ctx);

    conn = dct_ctx->conn;
    DEBUG(6, ("conn: %lX\n", conn));

    if((dct_ctx->disconnect) || (!dbus_connection_get_is_connected(conn))) {
        DEBUG(3,("Connection is not open for dispatching.\n"));
        /*
         * Free the connection object.
         * This will invoke the destructor for the connection
         */
        talloc_free(dct_ctx);
        dct_ctx = NULL;
        return;
    }

    /* Dispatch only once each time through the mainloop to avoid
     * starving other features
     */
    ret = dbus_connection_get_dispatch_status(conn);
    if (ret != DBUS_DISPATCH_COMPLETE) {
        DEBUG(6,("Dispatching.\n"));
        dbus_connection_dispatch(conn);
    }

    /* If other dispatches are waiting, queue up the do_dispatch function
     * for the next loop.
     */
    ret = dbus_connection_get_dispatch_status(conn);
    if (ret != DBUS_DISPATCH_COMPLETE) {
        new_event = tevent_add_timer(ev, dct_ctx, tv, sbus_dispatch, dct_ctx);
        if (new_event == NULL) {
            DEBUG(2,("Could not add dispatch event!\n"));

            /* TODO: Calling exit here is bad */
            exit(1);
        }
    }
}

/*
 * dbus_connection_read_write_handler
 * Callback for D-BUS to handle messages on a file-descriptor
 */
static void sbus_conn_read_write_handler(struct tevent_context *ev,
                                         struct tevent_fd *fde,
                                         uint16_t flags, void *data)
{
    struct sbus_conn_watch_ctx *conn_w_ctx;
    conn_w_ctx = talloc_get_type(data, struct sbus_conn_watch_ctx);

    DEBUG(6,("Connection is open for read/write.\n"));
    dbus_connection_ref(conn_w_ctx->top->conn);
    if (flags & TEVENT_FD_READ) {
        dbus_watch_handle(conn_w_ctx->watch, DBUS_WATCH_READABLE);
    }
    if (flags & TEVENT_FD_WRITE) {
        dbus_watch_handle(conn_w_ctx->watch, DBUS_WATCH_WRITABLE);
    }
    dbus_connection_unref(conn_w_ctx->top->conn);
}

/*
 * add_connection_watch
 * Set up hooks into the libevents mainloop for
 * D-BUS to add file descriptor-based events
 */
static dbus_bool_t sbus_add_conn_watch(DBusWatch *watch, void *data)
{
    unsigned int flags;
    unsigned int event_flags;
    struct sbus_conn_ctx *dt_ctx;
    struct sbus_conn_watch_ctx *conn_w_ctx;

    if (!dbus_watch_get_enabled(watch)) {
        return TRUE;
    }

    dt_ctx = talloc_get_type(data, struct sbus_conn_ctx);

    conn_w_ctx = talloc_zero(dt_ctx, struct sbus_conn_watch_ctx);
    conn_w_ctx->top = dt_ctx;
    conn_w_ctx->watch = watch;

    flags = dbus_watch_get_flags(watch);
    conn_w_ctx->fd = dbus_watch_get_unix_fd(watch);

    event_flags = 0;

    if (flags & DBUS_WATCH_READABLE)
        event_flags |= TEVENT_FD_READ;

    if (flags & DBUS_WATCH_WRITABLE)
        event_flags |= TEVENT_FD_WRITE;

    if (event_flags == 0)
        return FALSE;

    DEBUG(5,("%lX: %d, %d=%s\n",
             watch, conn_w_ctx->fd, event_flags,
             event_flags==TEVENT_FD_READ?"READ":"WRITE"));

    /* Add the file descriptor to the event loop */
    conn_w_ctx->fde = tevent_add_fd(conn_w_ctx->top->ev, conn_w_ctx,
                                   conn_w_ctx->fd, event_flags,
                                   sbus_conn_read_write_handler,
                                   conn_w_ctx);

    /* Save the event to the watch object so it can be removed later */
    dbus_watch_set_data(conn_w_ctx->watch,conn_w_ctx->fde,NULL);

    return TRUE;
}

/*
 * toggle_connection_watch
 * Hook for D-BUS to toggle the enabled/disabled state of
 * an event in the mainloop
 */
static void sbus_toggle_conn_watch(DBusWatch *watch, void *data)
{
    if (dbus_watch_get_enabled(watch)) {
        sbus_add_conn_watch(watch, data);
    } else {
        sbus_remove_watch(watch, data);
    }
}

/*
 * dbus_connection_timeout_handler
 * Callback for D-BUS to handle timed events
 */
static void sbus_conn_timeout_handler(struct tevent_context *ev,
                                            struct tevent_timer *te,
                                            struct timeval t, void *data)
{
    struct sbus_conn_timeout_ctx *conn_t_ctx;
    conn_t_ctx = talloc_get_type(data, struct sbus_conn_timeout_ctx);

    dbus_timeout_handle(conn_t_ctx->timeout);
}


/*
 * add_connection_timeout
 * Hook for D-BUS to add time-based events to the mainloop
 */
static dbus_bool_t sbus_add_conn_timeout(DBusTimeout *timeout, void *data)
{
    struct sbus_conn_ctx *dt_ctx;
    struct sbus_conn_timeout_ctx *conn_t_ctx;
    struct timeval tv;

    if (!dbus_timeout_get_enabled(timeout))
        return TRUE;

    dt_ctx = talloc_get_type(data, struct sbus_conn_ctx);

    conn_t_ctx = talloc_zero(dt_ctx,struct sbus_conn_timeout_ctx);
    conn_t_ctx->top = dt_ctx;
    conn_t_ctx->timeout = timeout;

    tv = _dbus_timeout_get_interval_tv(dbus_timeout_get_interval(timeout));

    struct timeval rightnow;
    gettimeofday(&rightnow, NULL);

    conn_t_ctx->te = tevent_add_timer(conn_t_ctx->top->ev, conn_t_ctx, tv,
            sbus_conn_timeout_handler, conn_t_ctx);

    /* Save the event to the watch object so it can be removed later */
    dbus_timeout_set_data(conn_t_ctx->timeout,conn_t_ctx->te,NULL);

    return TRUE;
}

/*
 * sbus_toggle_conn_timeout
 * Hook for D-BUS to toggle the enabled/disabled state of a mainloop
 * event
 */
void sbus_toggle_conn_timeout(DBusTimeout *timeout, void *data)
{
    if (dbus_timeout_get_enabled(timeout)) {
        sbus_add_conn_timeout(timeout, data);
    } else {
        sbus_remove_timeout(timeout, data);
    }
}

/* dbus_connection_wakeup_main
 * D-BUS makes a callback to the wakeup_main function when
 * it has data available for dispatching.
 * In order to avoid blocking, this function will create a now()
 * timed event to perform the dispatch during the next iteration
 * through the mainloop
 */
static void sbus_conn_wakeup_main(void *data)
{
    struct sbus_conn_ctx *dct_ctx;
    struct timeval tv;
    struct tevent_timer *te;

    dct_ctx = talloc_get_type(data, struct sbus_conn_ctx);
    gettimeofday(&tv, NULL);

    /* D-BUS calls this function when it is time to do a dispatch */
    te = tevent_add_timer(dct_ctx->ev, dct_ctx,
                         tv, sbus_dispatch, dct_ctx);
    if (te == NULL) {
        DEBUG(2,("Could not add dispatch event!\n"));
        /* TODO: Calling exit here is bad */
        exit(1);
    }
}

/*
 * integrate_connection_with_event_loop
 * Set up a D-BUS connection to use the libevents mainloop
 * for handling file descriptor and timed events
 */
int sbus_add_connection(TALLOC_CTX *ctx,
                        struct tevent_context *ev,
                        DBusConnection *dbus_conn,
                        struct sbus_conn_ctx **dct_ctx,
                        int connection_type)
{
    dbus_bool_t dbret;
    struct sbus_conn_ctx *dt_ctx;

    DEBUG(5,("Adding connection %lX\n", dbus_conn));
    dt_ctx = talloc_zero(ctx, struct sbus_conn_ctx);
    dt_ctx->ev = ev;
    dt_ctx->conn = dbus_conn;
    dt_ctx->connection_type = connection_type;
    dt_ctx->disconnect = 0;
    /* This will be replaced on the first call to sbus_conn_add_method_ctx() */
    dt_ctx->method_ctx_list = NULL;

    /*
     * Set the default destructor
     * Connections can override this with
     * sbus_conn_set_destructor
     */
    sbus_conn_set_destructor(dt_ctx, NULL);

    /* Set up DBusWatch functions */
    dbret = dbus_connection_set_watch_functions(dt_ctx->conn,
                                                sbus_add_conn_watch,
                                                sbus_remove_watch,
                                                sbus_toggle_conn_watch,
                                                dt_ctx, NULL);
    if (!dbret) {
        DEBUG(2,("Error setting up D-BUS connection watch functions\n"));
        return EIO;
    }

    /* Set up DBusTimeout functions */
    dbret = dbus_connection_set_timeout_functions(dt_ctx->conn,
                                                  sbus_add_conn_timeout,
                                                  sbus_remove_timeout,
                                                  sbus_toggle_conn_timeout,
                                                  dt_ctx, NULL);
    if (!dbret) {
        DEBUG(2,("Error setting up D-BUS server timeout functions\n"));
        /* FIXME: free resources ? */
        return EIO;
    }

    /* Set up dispatch handler */
    dbus_connection_set_wakeup_main_function(dt_ctx->conn,
                                             sbus_conn_wakeup_main,
                                             dt_ctx, NULL);

    /* Set up any method_contexts passed in */

    /* Attempt to dispatch immediately in case of opportunistic
     * services connecting before the handlers were all up.
     * If there are no messages to be dispatched, this will do
     * nothing.
     */
    sbus_conn_wakeup_main(dt_ctx);

    /* Return the new toplevel object */
    *dct_ctx = dt_ctx;

    return EOK;
}

/*int sbus_new_connection(struct sbus_method_ctx *ctx, const char *address,
                             DBusConnection **connection,
                             sbus_conn_destructor_fn destructor)*/
int sbus_new_connection(TALLOC_CTX *ctx, struct tevent_context *ev,
                        const char *address,
                        struct sbus_conn_ctx **dct_ctx,
                        sbus_conn_destructor_fn destructor)
{
    DBusConnection *dbus_conn;
    DBusError dbus_error;
    int ret;

    dbus_error_init(&dbus_error);

    /* Open a shared D-BUS connection to the address */
    dbus_conn = dbus_connection_open(address, &dbus_error);
    if (!dbus_conn) {
        DEBUG(1, ("Failed to open connection: name=%s, message=%s\n",
                dbus_error.name, dbus_error.message));
        if (dbus_error_is_set(&dbus_error)) dbus_error_free(&dbus_error);
        return EIO;
    }

    ret = sbus_add_connection(ctx, ev, dbus_conn,
                              dct_ctx, SBUS_CONN_TYPE_SHARED);
    if (ret != EOK) {
        /* FIXME: release resources */
    }

    dbus_connection_set_exit_on_disconnect((*dct_ctx)->conn, FALSE);

    /* Set connection destructor */
    sbus_conn_set_destructor(*dct_ctx, destructor);

    return ret;
}

/*
 * sbus_conn_set_destructor
 * Configures a callback to clean up this connection when it
 * is finalized.
 * @param dct_ctx The sbus_conn_ctx created
 * when this connection was established
 * @param destructor The destructor function that should be
 * called when the connection is finalized. If passed NULL,
 * this will reset the connection to the default destructor.
 */
void sbus_conn_set_destructor(struct sbus_conn_ctx *dct_ctx,
                              sbus_conn_destructor_fn destructor)
{
    if (!dct_ctx) return;

    dct_ctx->destructor = destructor;
    /* TODO: Should we try to handle the talloc_destructor too? */
}

int sbus_default_connection_destructor(void *ctx)
{
    struct sbus_conn_ctx *dct_ctx;
    dct_ctx = talloc_get_type(ctx, struct sbus_conn_ctx);

    DEBUG(5, ("Invoking default destructor on connection %lX\n", dct_ctx->conn));
    if (dct_ctx->connection_type == SBUS_CONN_TYPE_PRIVATE) {
        /* Private connections must be closed explicitly */
        dbus_connection_close(dct_ctx->conn);
    } else if (dct_ctx->connection_type == SBUS_CONN_TYPE_SHARED) {
        /* Shared connections are destroyed when their last reference is removed */
    }
    else {
        /* Critical Error! */
        DEBUG(1,("Critical Error, connection_type is neither shared nor private!\n"));
        return -1;
    }

    /* Remove object path */
    /* TODO: Remove object paths */

    dbus_connection_unref(dct_ctx->conn);
    return 0;
}

/*
 * sbus_get_connection
 * Utility function to retreive the DBusConnection object
 * from a sbus_conn_ctx
 */
DBusConnection *sbus_get_connection(struct sbus_conn_ctx *dct_ctx)
{
    return dct_ctx->conn;
}

void sbus_disconnect (struct sbus_conn_ctx *dct_ctx)
{
    if (dct_ctx == NULL) {
        return;
    }

    DEBUG(5,("Disconnecting %lX\n", dct_ctx->conn));

    /*******************************
     *  Referencing dct_ctx->conn */
    dbus_connection_ref(dct_ctx->conn);

    dct_ctx->disconnect = 1;

    /* Invoke the custom destructor, if it exists */
    if(dct_ctx->destructor) {
        dct_ctx->destructor(dct_ctx);
    }

    /* Unregister object paths */
    sbus_unreg_object_paths(dct_ctx);

    /* Disable watch functions */
    dbus_connection_set_watch_functions(dct_ctx->conn,
                                        NULL, NULL, NULL,
                                        NULL, NULL);
    /* Disable timeout functions */
    dbus_connection_set_timeout_functions(dct_ctx->conn,
                                          NULL, NULL, NULL,
                                          NULL, NULL);

    /* Disable dispatch status function */
    dbus_connection_set_dispatch_status_function(dct_ctx->conn, NULL, NULL, NULL);

    /* Disable wakeup main function */
    dbus_connection_set_wakeup_main_function(dct_ctx->conn, NULL, NULL, NULL);

    /* Finalize the connection */
    sbus_default_connection_destructor(dct_ctx);

    dbus_connection_unref(dct_ctx->conn);
    /* Unreferenced dct_ctx->conn *
     ******************************/

    DEBUG(5,("Disconnected %lX\n", dct_ctx->conn));
}

/* messsage_handler
 * Receive messages and process them
 */
DBusHandlerResult sbus_message_handler(DBusConnection *conn,
                                         DBusMessage *message,
                                         void *user_data)
{
    struct sbus_message_handler_ctx *ctx;
    const char *method;
    const char *path;
    const char *msg_interface;
    DBusMessage *reply = NULL;
    int i, ret;
    int found;

    if (!user_data) {
        return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
    }
    ctx = talloc_get_type(user_data, struct sbus_message_handler_ctx);

    method = dbus_message_get_member(message);
    path = dbus_message_get_path(message);
    msg_interface = dbus_message_get_interface(message);

    if (!method || !path || !msg_interface)
        return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;

    /* Validate the D-BUS path */
    if (strcmp(path, ctx->method_ctx->path) != 0)
        return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;

    /* Validate the method interface */
    if (strcmp(msg_interface, ctx->method_ctx->interface) == 0) {
        found = 0;
        for (i = 0; ctx->method_ctx->methods[i].method != NULL; i++) {
            if (strcmp(method, ctx->method_ctx->methods[i].method) == 0) {
                found = 1;
                ret = ctx->method_ctx->methods[i].fn(message, ctx->conn_ctx);
                if (ret != EOK) return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
                break;
            }
        }

        if (!found) {
            /* Reply DBUS_ERROR_UNKNOWN_METHOD */
            DEBUG(1, ("No matching method found for %s.\n", method));
            reply = dbus_message_new_error(message, DBUS_ERROR_UNKNOWN_METHOD, NULL);
        }
    }
    else {
        /* Special case: check for Introspection request
         * This is usually only useful for system bus connections
         */
        if (strcmp(msg_interface, DBUS_INTROSPECT_INTERFACE) == 0 &&
            strcmp(method, DBUS_INTROSPECT_METHOD) == 0)
        {
            if (ctx->method_ctx->introspect_fn) {
                /* If we have been asked for introspection data and we have
                 * an introspection function registered, user that.
                 */
                ret = ctx->method_ctx->introspect_fn(message, ctx->conn_ctx);
                if (ret != EOK) return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
            }
        }
        else
            return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
    }

    return DBUS_HANDLER_RESULT_HANDLED;
}

/* Adds a new D-BUS path message handler to the connection
 * Note: this must be a unique path.
 */
int sbus_conn_add_method_ctx(struct sbus_conn_ctx *dct_ctx,
                             struct sbus_method_ctx *method_ctx)
{
    DBusObjectPathVTable *connection_vtable;
    struct sbus_message_handler_ctx *msg_handler_ctx;
    TALLOC_CTX *tmp_ctx;

    dbus_bool_t dbret;
    if (!dct_ctx||!method_ctx) {
        return EINVAL;
    }

    if (_method_list_contains_path(dct_ctx->method_ctx_list, method_ctx)) {
        DEBUG(0, ("Cannot add method context with identical path.\n"));
        return EINVAL;
    }

    if (method_ctx->message_handler == NULL) {
        return EINVAL;
    }

    DLIST_ADD(dct_ctx->method_ctx_list, method_ctx);
    if((tmp_ctx = talloc_reference(dct_ctx, method_ctx))!=method_ctx) {
        /* talloc_reference only fails on insufficient memory */
        return ENOMEM;
    }

    /* Set up the vtable for the object path */
    connection_vtable = talloc_zero(dct_ctx, DBusObjectPathVTable);
    if (!connection_vtable) {
        return ENOMEM;
    }
    connection_vtable->message_function = method_ctx->message_handler;

    msg_handler_ctx = talloc_zero(dct_ctx, struct sbus_message_handler_ctx);
    if (!msg_handler_ctx) {
        talloc_free(connection_vtable);
        return ENOMEM;
    }
    msg_handler_ctx->conn_ctx = dct_ctx;
    msg_handler_ctx->method_ctx = method_ctx;

    dbret = dbus_connection_register_object_path(dct_ctx->conn, method_ctx->path,
                                                 connection_vtable, msg_handler_ctx);
    if (!dbret) {
        DEBUG(0, ("Could not register object path to the connection.\n"));
        return ENOMEM;
    }

    return EOK;
}

static int _method_list_contains_path(struct sbus_method_ctx *list,
                                      struct sbus_method_ctx *method)
{
    struct sbus_method_ctx *iter;

    if (!list || !method) {
        return 0; /* FALSE */
    }

    iter = list;
    while (iter != NULL) {
        if (strcmp(iter->path, method->path) == 0)
            return 1; /* TRUE */

        iter = iter->next;
    }

    return 0; /* FALSE */
}

static void sbus_unreg_object_paths(struct sbus_conn_ctx *dct_ctx)
{
    struct sbus_method_ctx *iter = dct_ctx->method_ctx_list;
    struct sbus_method_ctx *purge;

    while (iter != NULL) {
        dbus_connection_unregister_object_path(dct_ctx->conn, iter->path);
        DLIST_REMOVE(dct_ctx->method_ctx_list, iter);
        purge = iter;
        iter = iter->next;
        talloc_unlink(dct_ctx, purge);
    }
}

void sbus_conn_set_private_data(struct sbus_conn_ctx *conn_ctx, void *pvt_data)
{
    conn_ctx->pvt_data = pvt_data;
}

void *sbus_conn_get_private_data(struct sbus_conn_ctx *conn_ctx)
{
    return conn_ctx->pvt_data;
}

bool sbus_conn_disconnecting(struct sbus_conn_ctx *conn_ctx)
{
    if (conn_ctx->disconnect == 1) return true;
    return false;
}

void sbus_conn_send_reply(struct sbus_conn_ctx *conn_ctx, DBusMessage *reply)
{
    dbus_connection_send(conn_ctx->conn, reply, NULL);
}