sssd_dbus_connection.c revision 19b4bb652f5cdc2797b66595eaf8811881aa9873
/*
Authors:
Simo Sorce <ssorce@redhat.com>
Stephen Gallagher <sgallagh@redhat.com>
Copyright (C) 2009 Red Hat
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <sys/time.h>
#include <dbus/dbus.h>
#include "util/util.h"
#include "sbus/sssd_dbus.h"
#include "sbus/sssd_dbus_private.h"
/* Types */
struct dbus_ctx_list;
struct sbus_interface_p {
struct sbus_interface_p *prev, *next;
struct sbus_connection *conn;
struct sbus_interface *intf;
};
static bool path_in_interface_list(struct sbus_interface_p *list,
const char *path);
static void sbus_unreg_object_paths(struct sbus_connection *conn);
static int sbus_auto_reconnect(struct sbus_connection *conn);
static void sbus_dispatch(struct tevent_context *ev,
struct tevent_timer *te,
struct timeval tv, void *data)
{
struct tevent_timer *new_event;
struct sbus_connection *conn;
DBusConnection *dbus_conn;
int ret;
if (data == NULL) return;
conn = talloc_get_type(data, struct sbus_connection);
dbus_conn = conn->dbus.conn;
DEBUG(SSSDBG_TRACE_ALL, ("dbus conn: %p\n", dbus_conn));
if (conn->retries > 0) {
DEBUG(6, ("SBUS is reconnecting. Deferring.\n"));
/* Currently trying to reconnect, defer dispatch for 30ms */
tv = tevent_timeval_current_ofs(0, 30);
new_event = tevent_add_timer(ev, conn, tv, sbus_dispatch, conn);
if (new_event == NULL) {
DEBUG(0,("Could not defer dispatch!\n"));
}
return;
}
if ((!dbus_connection_get_is_connected(dbus_conn)) &&
(conn->max_retries != 0)) {
/* Attempt to reconnect automatically */
ret = sbus_auto_reconnect(conn);
if (ret == EOK) {
DEBUG(1, ("Performing auto-reconnect\n"));
return;
}
DEBUG(0, ("Cannot start auto-reconnection.\n"));
conn->reconnect_callback(conn,
SBUS_RECONNECT_ERROR,
conn->reconnect_pvt);
return;
}
if ((conn->disconnect) ||
(!dbus_connection_get_is_connected(dbus_conn))) {
DEBUG(3,("Connection is not open for dispatching.\n"));
/*
* Free the connection object.
* This will invoke the destructor for the connection
*/
talloc_free(conn);
conn = NULL;
return;
}
/* Dispatch only once each time through the mainloop to avoid
* starving other features
*/
ret = dbus_connection_get_dispatch_status(dbus_conn);
if (ret != DBUS_DISPATCH_COMPLETE) {
DEBUG(9,("Dispatching.\n"));
dbus_connection_dispatch(dbus_conn);
}
/* If other dispatches are waiting, queue up the dispatch function
* for the next loop.
*/
ret = dbus_connection_get_dispatch_status(dbus_conn);
if (ret != DBUS_DISPATCH_COMPLETE) {
new_event = tevent_add_timer(ev, conn, tv, sbus_dispatch, conn);
if (new_event == NULL) {
DEBUG(2,("Could not add dispatch event!\n"));
/* TODO: Calling exit here is bad */
exit(1);
}
}
}
/* 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_connection *conn;
struct timeval tv;
struct tevent_timer *te;
conn = talloc_get_type(data, struct sbus_connection);
tv = tevent_timeval_current();
/* D-BUS calls this function when it is time to do a dispatch */
te = tevent_add_timer(conn->ev, conn, tv, sbus_dispatch, conn);
if (te == NULL) {
DEBUG(2,("Could not add dispatch event!\n"));
/* TODO: Calling exit here is bad */
exit(1);
}
}
static int sbus_conn_set_fns(struct sbus_connection *conn);
/*
* 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_init_connection(TALLOC_CTX *ctx,
struct tevent_context *ev,
DBusConnection *dbus_conn,
struct sbus_interface *intf,
int connection_type,
struct sbus_connection **_conn)
{
struct sbus_connection *conn;
int ret;
DEBUG(SSSDBG_TRACE_FUNC,("Adding connection %p\n", dbus_conn));
conn = talloc_zero(ctx, struct sbus_connection);
conn->ev = ev;
conn->type = SBUS_CONNECTION;
conn->dbus.conn = dbus_conn;
conn->connection_type = connection_type;
ret = sbus_conn_add_interface(conn, intf);
if (ret != EOK) {
talloc_free(conn);
return ret;
}
ret = sbus_conn_set_fns(conn);
if (ret != EOK) {
talloc_free(conn);
return ret;
}
*_conn = conn;
return ret;
}
static int sbus_conn_set_fns(struct sbus_connection *conn)
{
dbus_bool_t dbret;
/*
* Set the default destructor
* Connections can override this with
* sbus_conn_set_destructor
*/
sbus_conn_set_destructor(conn, NULL);
/* Set up DBusWatch functions */
dbret = dbus_connection_set_watch_functions(conn->dbus.conn,
sbus_add_watch,
sbus_remove_watch,
sbus_toggle_watch,
conn, 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(conn->dbus.conn,
sbus_add_timeout,
sbus_remove_timeout,
sbus_toggle_timeout,
conn, 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(conn->dbus.conn,
sbus_conn_wakeup_main,
conn, 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(conn);
return EOK;
}
int sbus_new_connection(TALLOC_CTX *ctx, struct tevent_context *ev,
const char *address, struct sbus_interface *intf,
struct sbus_connection **_conn)
{
struct sbus_connection *conn;
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_init_connection(ctx, ev, dbus_conn, intf,
SBUS_CONN_TYPE_SHARED, &conn);
if (ret != EOK) {
/* FIXME: release resources */
}
/* Store the address for later reconnection */
conn->address = talloc_strdup(conn, address);
dbus_connection_set_exit_on_disconnect(conn->dbus.conn, FALSE);
*_conn = conn;
return ret;
}
/*
* sbus_conn_set_destructor
* Configures a callback to clean up this connection when it
* is finalized.
* @param conn The sbus_connection 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_connection *conn,
sbus_conn_destructor_fn destructor)
{
if (!conn) return;
conn->destructor = destructor;
/* TODO: Should we try to handle the talloc_destructor too? */
}
int sbus_default_connection_destructor(void *ctx)
{
struct sbus_connection *conn;
conn = talloc_get_type(ctx, struct sbus_connection);
DEBUG(SSSDBG_TRACE_FUNC, ("Invoking default destructor on connection %p\n",
conn->dbus.conn));
if (conn->connection_type == SBUS_CONN_TYPE_PRIVATE) {
/* Private connections must be closed explicitly */
dbus_connection_close(conn->dbus.conn);
}
else if (conn->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(conn->dbus.conn);
return 0;
}
/*
* sbus_get_connection
* Utility function to retreive the DBusConnection object
* from a sbus_connection
*/
DBusConnection *sbus_get_connection(struct sbus_connection *conn)
{
return conn->dbus.conn;
}
void sbus_disconnect (struct sbus_connection *conn)
{
if (conn == NULL) {
return;
}
DEBUG(SSSDBG_TRACE_FUNC, ("Disconnecting %p\n", conn->dbus.conn));
/*******************************
* Referencing conn->dbus.conn */
dbus_connection_ref(conn->dbus.conn);
conn->disconnect = 1;
/* Invoke the custom destructor, if it exists */
if (conn->destructor) {
conn->destructor(conn);
}
/* Unregister object paths */
sbus_unreg_object_paths(conn);
/* Disable watch functions */
dbus_connection_set_watch_functions(conn->dbus.conn,
NULL, NULL, NULL,
NULL, NULL);
/* Disable timeout functions */
dbus_connection_set_timeout_functions(conn->dbus.conn,
NULL, NULL, NULL,
NULL, NULL);
/* Disable dispatch status function */
dbus_connection_set_dispatch_status_function(conn->dbus.conn,
NULL, NULL, NULL);
/* Disable wakeup main function */
dbus_connection_set_wakeup_main_function(conn->dbus.conn,
NULL, NULL, NULL);
/* Finalize the connection */
sbus_default_connection_destructor(conn);
dbus_connection_unref(conn->dbus.conn);
/* Unreferenced conn->dbus_conn *
******************************/
DEBUG(SSSDBG_TRACE_FUNC ,("Disconnected %p\n", conn->dbus.conn));
}
static int sbus_reply_internal_error(DBusMessage *message,
struct sbus_connection *conn) {
DBusMessage *reply = dbus_message_new_error(message, DBUS_ERROR_IO_ERROR,
"Internal Error");
if (reply) {
sbus_conn_send_reply(conn, reply);
dbus_message_unref(reply);
return DBUS_HANDLER_RESULT_HANDLED;
}
return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
}
/* messsage_handler
* Receive messages and process them
*/
DBusHandlerResult sbus_message_handler(DBusConnection *dbus_conn,
DBusMessage *message,
void *user_data)
{
struct sbus_interface_p *intf_p;
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;
}
intf_p = talloc_get_type(user_data, struct sbus_interface_p);
method = dbus_message_get_member(message);
DEBUG(9, ("Received SBUS method [%s]\n", method));
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, intf_p->intf->path) != 0)
return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
/* Validate the method interface */
if (strcmp(msg_interface, intf_p->intf->interface) == 0) {
found = 0;
for (i = 0; intf_p->intf->methods[i].method != NULL; i++) {
if (strcmp(method, intf_p->intf->methods[i].method) == 0) {
found = 1;
ret = intf_p->intf->methods[i].fn(message, intf_p->conn);
if (ret != EOK) {
return sbus_reply_internal_error(message, intf_p->conn);
}
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);
sbus_conn_send_reply(intf_p->conn, reply);
dbus_message_unref(reply);
}
}
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 (intf_p->intf->introspect_fn) {
/* If we have been asked for introspection data and we have
* an introspection function registered, user that.
*/
ret = intf_p->intf->introspect_fn(message, intf_p->conn);
if (ret != EOK) {
return sbus_reply_internal_error(message, intf_p->conn);
}
}
}
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_interface(struct sbus_connection *conn,
struct sbus_interface *intf)
{
struct sbus_interface_p *intf_p;
dbus_bool_t dbret;
const char *path;
if (!conn || !intf || !intf->vtable.message_function) {
return EINVAL;
}
path = intf->path;
if (path_in_interface_list(conn->intf_list, path)) {
DEBUG(0, ("Cannot add method context with identical path.\n"));
return EINVAL;
}
intf_p = talloc_zero(conn, struct sbus_interface_p);
if (!intf_p) {
return ENOMEM;
}
intf_p->conn = conn;
intf_p->intf = intf;
DLIST_ADD(conn->intf_list, intf_p);
dbret = dbus_connection_register_object_path(conn->dbus.conn,
path, &intf->vtable, intf_p);
if (!dbret) {
DEBUG(0, ("Could not register object path to the connection.\n"));
return ENOMEM;
}
return EOK;
}
static bool path_in_interface_list(struct sbus_interface_p *list,
const char *path)
{
struct sbus_interface_p *iter;
if (!list || !path) {
return false;
}
iter = list;
while (iter != NULL) {
if (strcmp(iter->intf->path, path) == 0) {
return true;
}
iter = iter->next;
}
return false;
}
static void sbus_unreg_object_paths(struct sbus_connection *conn)
{
struct sbus_interface_p *iter = conn->intf_list;
while (iter != NULL) {
dbus_connection_unregister_object_path(conn->dbus.conn,
iter->intf->path);
iter = iter->next;
}
}
void sbus_conn_set_private_data(struct sbus_connection *conn, void *pvt_data)
{
conn->pvt_data = pvt_data;
}
void *sbus_conn_get_private_data(struct sbus_connection *conn)
{
return conn->pvt_data;
}
static void sbus_reconnect(struct tevent_context *ev,
struct tevent_timer *te,
struct timeval tv, void *data)
{
struct sbus_connection *conn;
struct sbus_interface_p *iter;
DBusError dbus_error;
dbus_bool_t dbret;
int ret;
conn = talloc_get_type(data, struct sbus_connection);
dbus_error_init(&dbus_error);
DEBUG(3, ("Making reconnection attempt %d to [%s]\n",
conn->retries, conn->address));
conn->dbus.conn = dbus_connection_open(conn->address, &dbus_error);
if (conn->dbus.conn) {
/* We successfully reconnected. Set up mainloop integration. */
DEBUG(3, ("Reconnected to [%s]\n", conn->address));
ret = sbus_conn_set_fns(conn);
if (ret != EOK) {
dbus_connection_unref(conn->dbus.conn);
goto failed;
}
/* Re-register object paths */
iter = conn->intf_list;
while (iter) {
dbret = dbus_connection_register_object_path(conn->dbus.conn,
iter->intf->path,
&iter->intf->vtable,
iter);
if (!dbret) {
DEBUG(0, ("Could not register object path.\n"));
dbus_connection_unref(conn->dbus.conn);
goto failed;
}
iter = iter->next;
}
/* Reset retries to 0 to resume dispatch processing */
conn->retries = 0;
/* Notify the owner of this connection that the
* reconnection was successful
*/
conn->reconnect_callback(conn,
SBUS_RECONNECT_SUCCESS,
conn->reconnect_pvt);
return;
}
failed:
/* Reconnection failed, try again in a few seconds */
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);
conn->retries++;
/* Check if we've passed our last chance or if we've lost track of
* our retry count somehow
*/
if ((conn->retries > conn->max_retries) || (conn->retries <= 0)) {
conn->reconnect_callback(conn,
SBUS_RECONNECT_EXCEEDED_RETRIES,
conn->reconnect_pvt);
}
if (conn->retries == 2) {
/* Wait 3 seconds before the second reconnect attempt */
tv.tv_sec += 3;
}
else if (conn->retries == 3) {
/* Wait 10 seconds before the third reconnect attempt */
tv.tv_sec += 10;
}
else {
/* Wait 30 seconds before all subsequent reconnect attempts */
tv.tv_sec += 30;
}
te = tevent_add_timer(conn->ev, conn, tv, sbus_reconnect, conn);
if (!te) {
conn->reconnect_callback(conn,
SBUS_RECONNECT_ERROR,
conn->reconnect_pvt);
}
}
/* This function will free and recreate the sbus_connection,
* calling functions need to be aware of this (and whether
* they have attached a talloc destructor to the
* sbus_connection.
*/
static int sbus_auto_reconnect(struct sbus_connection *conn)
{
struct tevent_timer *te = NULL;
struct timeval tv;
conn->retries++;
if (conn->retries >= conn->max_retries) {
/* Return EIO (to tell the calling process it
* needs to create a new connection from scratch
*/
return EIO;
}
gettimeofday(&tv, NULL);
tv.tv_sec += 1; /* Wait 1 second before the first reconnect attempt */
te = tevent_add_timer(conn->ev, conn, tv, sbus_reconnect, conn);
if (!te) {
return EIO;
}
return EOK;
}
/* Max retries */
void sbus_reconnect_init(struct sbus_connection *conn,
int max_retries,
sbus_conn_reconn_callback_fn callback,
void *pvt)
{
if (max_retries < 0 || callback == NULL) return;
conn->retries = 0;
conn->max_retries = max_retries;
conn->reconnect_callback = callback;
conn->reconnect_pvt = pvt;
}
bool sbus_conn_disconnecting(struct sbus_connection *conn)
{
if (conn->disconnect == 1) return true;
return false;
}
/*
* Send a message across the SBUS
* If requested, the DBusPendingCall object will
* be returned to the caller.
*
* This function will return EAGAIN in the event
* that the connection is not open for
* communication.
*/
int sbus_conn_send(struct sbus_connection *conn,
DBusMessage *msg,
int timeout_ms,
DBusPendingCallNotifyFunction reply_handler,
void *pvt,
DBusPendingCall **pending)
{
DBusPendingCall *pending_reply;
DBusConnection *dbus_conn;
dbus_bool_t dbret;
dbus_conn = sbus_get_connection(conn);
if (!dbus_conn) {
DEBUG(SSSDBG_CRIT_FAILURE, ("D-BUS not connected\n"));
return ENOTCONN;
}
dbret = dbus_connection_send_with_reply(dbus_conn, msg,
&pending_reply,
timeout_ms);
if (!dbret) {
/*
* Critical Failure
* Insufficient memory to send message
*/
DEBUG(0, ("D-BUS send failed.\n"));
return ENOMEM;
}
if (pending_reply) {
/* Set up the reply handler */
dbret = dbus_pending_call_set_notify(pending_reply, reply_handler,
pvt, NULL);
if (!dbret) {
/*
* Critical Failure
* Insufficient memory to create pending call notify
*/
DEBUG(0, ("D-BUS send failed.\n"));
dbus_pending_call_cancel(pending_reply);
dbus_pending_call_unref(pending_reply);
return ENOMEM;
}
if(pending) {
*pending = pending_reply;
}
return EOK;
}
/* If pending_reply is NULL, the connection was not
* open for sending.
*/
/* TODO: Create a callback into the reconnection logic so this
* request is invoked when the connection is re-established
*/
return EAGAIN;
}
void sbus_conn_send_reply(struct sbus_connection *conn, DBusMessage *reply)
{
dbus_connection_send(conn->dbus.conn, reply, NULL);
}