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dbus-bus.c

00001 /* -*- mode: C; c-file-style: "gnu" -*- */
00002 /* dbus-bus.c  Convenience functions for communicating with the bus.
00003  *
00004  * Copyright (C) 2003  CodeFactory AB
00005  * Copyright (C) 2003  Red Hat, Inc.
00006  *
00007  * Licensed under the Academic Free License version 1.2
00008  * 
00009  * This program is free software; you can redistribute it and/or modify
00010  * it under the terms of the GNU General Public License as published by
00011  * the Free Software Foundation; either version 2 of the License, or
00012  * (at your option) any later version.
00013  *
00014  * This program is distributed in the hope that it will be useful,
00015  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00016  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00017  * GNU General Public License for more details.
00018  * 
00019  * You should have received a copy of the GNU General Public License
00020  * along with this program; if not, write to the Free Software
00021  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
00022  *
00023  */
00024 
00025 #include "dbus-bus.h"
00026 #include "dbus-protocol.h"
00027 #include "dbus-internals.h"
00028 #include "dbus-message.h"
00029 #include <string.h>
00030 
00061 typedef struct
00062 {
00063   DBusConnection *connection; 
00064   char *base_service; 
00066   unsigned int is_well_known : 1; 
00067 } BusData;
00068 
00071 static dbus_int32_t bus_data_slot = -1;
00072 
00074 #define N_BUS_TYPES 3
00075 
00076 static DBusConnection *bus_connections[N_BUS_TYPES];
00077 static char *bus_connection_addresses[N_BUS_TYPES] = { NULL, NULL, NULL };
00078 
00079 static DBusBusType activation_bus_type = DBUS_BUS_ACTIVATION;
00080 
00081 static dbus_bool_t initialized = FALSE;
00082 
00086 _DBUS_DEFINE_GLOBAL_LOCK (bus);
00087 
00088 static void
00089 addresses_shutdown_func (void *data)
00090 {
00091   int i;
00092 
00093   i = 0;
00094   while (i < N_BUS_TYPES)
00095     {
00096       if (bus_connections[i] != NULL)
00097         _dbus_warn ("dbus_shutdown() called but connections were still live!");
00098       
00099       dbus_free (bus_connection_addresses[i]);
00100       bus_connection_addresses[i] = NULL;
00101       ++i;
00102     }
00103 
00104   activation_bus_type = DBUS_BUS_ACTIVATION;
00105 }
00106 
00107 static dbus_bool_t
00108 get_from_env (char           **connection_p,
00109               const char      *env_var)
00110 {
00111   const char *s;
00112   
00113   _dbus_assert (*connection_p == NULL);
00114   
00115   s = _dbus_getenv (env_var);
00116   if (s == NULL || *s == '\0')
00117     return TRUE; /* successfully didn't use the env var */
00118   else
00119     {
00120       *connection_p = _dbus_strdup (s);
00121       return *connection_p != NULL;
00122     }
00123 }
00124 
00125 static dbus_bool_t
00126 init_connections_unlocked (void)
00127 {
00128   if (!initialized)
00129     {
00130       const char *s;
00131       int i;
00132 
00133       i = 0;
00134       while (i < N_BUS_TYPES)
00135         {
00136           bus_connections[i] = NULL;
00137           ++i;
00138         }
00139 
00140       /* Don't init these twice, we may run this code twice if
00141        * init_connections_unlocked() fails midway through.
00142        * In practice, each block below should contain only one
00143        * "return FALSE" or running through twice may not
00144        * work right.
00145        */
00146       
00147        if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL)
00148          {
00149            _dbus_verbose ("Filling in system bus address...\n");
00150            
00151            if (!get_from_env (&bus_connection_addresses[DBUS_BUS_SYSTEM],
00152                               "DBUS_SYSTEM_BUS_ADDRESS"))
00153              return FALSE;
00154          }
00155 
00156                   
00157        if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL)
00158          {
00159            /* Use default system bus address if none set in environment */
00160            bus_connection_addresses[DBUS_BUS_SYSTEM] =
00161              _dbus_strdup (DBUS_SYSTEM_BUS_DEFAULT_ADDRESS);
00162            if (bus_connection_addresses[DBUS_BUS_SYSTEM] == NULL)
00163              return FALSE;
00164            
00165            _dbus_verbose ("  used default system bus \"%s\"\n",
00166                           bus_connection_addresses[DBUS_BUS_SYSTEM]);
00167          }
00168        else
00169          _dbus_verbose ("  used env var system bus \"%s\"\n",
00170                         bus_connection_addresses[DBUS_BUS_SYSTEM]);
00171           
00172       if (bus_connection_addresses[DBUS_BUS_SESSION] == NULL)
00173         {
00174           _dbus_verbose ("Filling in session bus address...\n");
00175           
00176           if (!get_from_env (&bus_connection_addresses[DBUS_BUS_SESSION],
00177                              "DBUS_SESSION_BUS_ADDRESS"))
00178             return FALSE;
00179           _dbus_verbose ("  \"%s\"\n", bus_connection_addresses[DBUS_BUS_SESSION] ?
00180                          bus_connection_addresses[DBUS_BUS_SESSION] : "none set");
00181         }
00182 
00183       if (bus_connection_addresses[DBUS_BUS_ACTIVATION] == NULL)
00184         {
00185           _dbus_verbose ("Filling in activation bus address...\n");
00186           
00187           if (!get_from_env (&bus_connection_addresses[DBUS_BUS_ACTIVATION],
00188                              "DBUS_ACTIVATION_ADDRESS"))
00189             return FALSE;
00190           
00191           _dbus_verbose ("  \"%s\"\n", bus_connection_addresses[DBUS_BUS_ACTIVATION] ?
00192                          bus_connection_addresses[DBUS_BUS_ACTIVATION] : "none set");
00193         }
00194 
00195 
00196       if (bus_connection_addresses[DBUS_BUS_ACTIVATION] != NULL)
00197         {
00198           s = _dbus_getenv ("DBUS_ACTIVATION_BUS_TYPE");
00199               
00200           if (s != NULL)
00201             {
00202               _dbus_verbose ("Bus activation type was set to \"%s\"\n", s);
00203                   
00204               if (strcmp (s, "system") == 0)
00205                 activation_bus_type = DBUS_BUS_SYSTEM;
00206               else if (strcmp (s, "session") == 0)
00207                 activation_bus_type = DBUS_BUS_SESSION;
00208             }
00209         }
00210       else
00211         {
00212           /* Default to the session bus instead if available */
00213           if (bus_connection_addresses[DBUS_BUS_SESSION] != NULL)
00214             {
00215               bus_connection_addresses[DBUS_BUS_ACTIVATION] =
00216                 _dbus_strdup (bus_connection_addresses[DBUS_BUS_SESSION]);
00217               if (bus_connection_addresses[DBUS_BUS_ACTIVATION] == NULL)
00218                 return FALSE;
00219             }
00220         }
00221       
00222       /* If we return FALSE we have to be sure that restarting
00223        * the above code will work right
00224        */
00225       
00226       if (!_dbus_setenv ("DBUS_ACTIVATION_ADDRESS", NULL))
00227         return FALSE;
00228 
00229       if (!_dbus_setenv ("DBUS_ACTIVATION_BUS_TYPE", NULL))
00230         return FALSE;
00231       
00232       if (!_dbus_register_shutdown_func (addresses_shutdown_func,
00233                                          NULL))
00234         return FALSE;
00235       
00236       initialized = TRUE;
00237     }
00238 
00239   return initialized;
00240 }
00241 
00242 static void
00243 bus_data_free (void *data)
00244 {
00245   BusData *bd = data;
00246   
00247   if (bd->is_well_known)
00248     {
00249       int i;
00250       _DBUS_LOCK (bus);
00251       /* We may be stored in more than one slot */
00252       i = 0;
00253       while (i < N_BUS_TYPES)
00254         {
00255           if (bus_connections[i] == bd->connection)
00256             bus_connections[i] = NULL;
00257           
00258           ++i;
00259         }
00260       _DBUS_UNLOCK (bus);
00261     }
00262   
00263   dbus_free (bd->base_service);
00264   dbus_free (bd);
00265 
00266   dbus_connection_free_data_slot (&bus_data_slot);
00267 }
00268 
00269 static BusData*
00270 ensure_bus_data (DBusConnection *connection)
00271 {
00272   BusData *bd;
00273 
00274   if (!dbus_connection_allocate_data_slot (&bus_data_slot))
00275     return NULL;
00276 
00277   bd = dbus_connection_get_data (connection, bus_data_slot);
00278   if (bd == NULL)
00279     {      
00280       bd = dbus_new0 (BusData, 1);
00281       if (bd == NULL)
00282         {
00283           dbus_connection_free_data_slot (&bus_data_slot);
00284           return NULL;
00285         }
00286 
00287       bd->connection = connection;
00288       
00289       if (!dbus_connection_set_data (connection, bus_data_slot, bd,
00290                                      bus_data_free))
00291         {
00292           dbus_free (bd);
00293           dbus_connection_free_data_slot (&bus_data_slot);
00294           return NULL;
00295         }
00296 
00297       /* Data slot refcount now held by the BusData */
00298     }
00299   else
00300     {
00301       dbus_connection_free_data_slot (&bus_data_slot);
00302     }
00303 
00304   return bd;
00305 }
00306  /* end of implementation details docs */
00308 
00324 DBusConnection *
00325 dbus_bus_get (DBusBusType  type,
00326               DBusError   *error)
00327 {
00328   const char *address;
00329   DBusConnection *connection;
00330   BusData *bd;
00331   DBusBusType address_type;
00332 
00333   _dbus_return_val_if_fail (type >= 0 && type < N_BUS_TYPES, NULL);
00334   _dbus_return_val_if_error_is_set (error, NULL);
00335 
00336   _DBUS_LOCK (bus);
00337 
00338   if (!init_connections_unlocked ())
00339     {
00340       _DBUS_UNLOCK (bus);
00341       dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
00342       return NULL;
00343     }
00344 
00345   /* We want to use the activation address even if the
00346    * activating bus is the session or system bus,
00347    * per the spec.
00348    */
00349   address_type = type;
00350   
00351   /* Use the real type of the activation bus for getting its
00352    * connection, but only if the real type's address is available. (If
00353    * the activating bus isn't a well-known bus then
00354    * activation_bus_type == DBUS_BUS_ACTIVATION)
00355    */
00356   if (type == DBUS_BUS_ACTIVATION &&
00357       bus_connection_addresses[activation_bus_type] != NULL)
00358     type = activation_bus_type;
00359   
00360   if (bus_connections[type] != NULL)
00361     {
00362       connection = bus_connections[type];
00363       dbus_connection_ref (connection);
00364       
00365       _DBUS_UNLOCK (bus);
00366       return connection;
00367     }
00368 
00369   address = bus_connection_addresses[address_type];
00370   if (address == NULL)
00371     {
00372       dbus_set_error (error, DBUS_ERROR_FAILED,
00373                       "Unable to determine the address of the message bus");
00374       _DBUS_UNLOCK (bus);
00375       return NULL;
00376     }
00377 
00378   connection = dbus_connection_open (address, error);
00379   
00380   if (!connection)
00381     {
00382       _DBUS_ASSERT_ERROR_IS_SET (error);
00383       _DBUS_UNLOCK (bus);
00384       return NULL;
00385     }
00386 
00387   /* By default we're bound to the lifecycle of
00388    * the message bus.
00389    */
00390   dbus_connection_set_exit_on_disconnect (connection,
00391                                           TRUE);
00392   
00393   if (!dbus_bus_register (connection, error))
00394     {
00395       _DBUS_ASSERT_ERROR_IS_SET (error);
00396       dbus_connection_disconnect (connection);
00397       dbus_connection_unref (connection);
00398 
00399       _DBUS_UNLOCK (bus);
00400       return NULL;
00401     }
00402 
00403   bus_connections[type] = connection;
00404   bd = ensure_bus_data (connection);
00405   _dbus_assert (bd != NULL);
00406 
00407   bd->is_well_known = TRUE;
00408 
00409   _DBUS_UNLOCK (bus);
00410   return connection;
00411 }
00412 
00413 
00427 dbus_bool_t
00428 dbus_bus_register (DBusConnection *connection,
00429                    DBusError      *error)
00430 {
00431   DBusMessage *message, *reply;
00432   char *name;
00433   BusData *bd;
00434   dbus_bool_t retval;
00435 
00436   _dbus_return_val_if_fail (connection != NULL, FALSE);
00437   _dbus_return_val_if_error_is_set (error, FALSE);
00438 
00439   retval = FALSE;
00440   
00441   bd = ensure_bus_data (connection);
00442   if (bd == NULL)
00443     {
00444       _DBUS_SET_OOM (error);
00445       return FALSE;
00446     }
00447 
00448   if (bd->base_service != NULL)
00449     {
00450       _dbus_warn ("Attempt to register the same DBusConnection with the message bus, but it is already registered\n");
00451       /* This isn't an error, it's a programming bug. We'll be nice
00452        * and not _dbus_assert_not_reached()
00453        */
00454       return TRUE;
00455     }
00456   
00457   message = dbus_message_new_method_call (DBUS_SERVICE_ORG_FREEDESKTOP_DBUS,
00458                                           DBUS_PATH_ORG_FREEDESKTOP_DBUS,
00459                                           DBUS_INTERFACE_ORG_FREEDESKTOP_DBUS,
00460                                           "Hello"); 
00461 
00462   if (!message)
00463     {
00464       _DBUS_SET_OOM (error);
00465       return FALSE;
00466     }
00467   
00468   reply = dbus_connection_send_with_reply_and_block (connection, message, -1, error);
00469 
00470   dbus_message_unref (message);
00471   
00472   if (reply == NULL)
00473     goto out;
00474   else if (dbus_set_error_from_message (error, reply))
00475     goto out;
00476   else if (!dbus_message_get_args (reply, error,
00477                                    DBUS_TYPE_STRING, &name,
00478                                    DBUS_TYPE_INVALID))
00479     goto out;
00480   
00481   bd->base_service = name;
00482 
00483   retval = TRUE;
00484   
00485  out:
00486   if (reply)
00487     dbus_message_unref (reply);
00488 
00489   if (!retval)
00490     _DBUS_ASSERT_ERROR_IS_SET (error);
00491   
00492   return retval;
00493 }
00494 
00495 
00507 dbus_bool_t
00508 dbus_bus_set_base_service (DBusConnection *connection,
00509                            const char     *base_service)
00510 {
00511   BusData *bd;
00512 
00513   _dbus_return_val_if_fail (connection != NULL, FALSE);
00514   _dbus_return_val_if_fail (base_service != NULL, FALSE);
00515   
00516   bd = ensure_bus_data (connection);
00517   if (bd == NULL)
00518     return FALSE;
00519 
00520   _dbus_assert (bd->base_service == NULL);
00521   
00522   bd->base_service = _dbus_strdup (base_service);
00523   return bd->base_service != NULL;
00524 }
00525 
00534 const char*
00535 dbus_bus_get_base_service (DBusConnection *connection)
00536 {
00537   BusData *bd;
00538 
00539   _dbus_return_val_if_fail (connection != NULL, NULL);
00540   
00541   bd = ensure_bus_data (connection);
00542   if (bd == NULL)
00543     return NULL;
00544   
00545   return bd->base_service;
00546 }
00547 
00563 int
00564 dbus_bus_acquire_service (DBusConnection *connection,
00565                           const char     *service_name,
00566                           unsigned int    flags,
00567                           DBusError      *error)
00568 {
00569   DBusMessage *message, *reply;
00570   dbus_uint32_t service_result;
00571 
00572   _dbus_return_val_if_fail (connection != NULL, 0);
00573   _dbus_return_val_if_fail (service_name != NULL, 0);
00574   _dbus_return_val_if_error_is_set (error, 0);
00575   
00576   message = dbus_message_new_method_call (DBUS_SERVICE_ORG_FREEDESKTOP_DBUS,
00577                                           DBUS_PATH_ORG_FREEDESKTOP_DBUS,
00578                                           DBUS_INTERFACE_ORG_FREEDESKTOP_DBUS,
00579                                           "AcquireService");
00580 
00581   if (message == NULL)
00582     {
00583       _DBUS_SET_OOM (error);
00584       return -1;
00585     }
00586  
00587   if (!dbus_message_append_args (message,
00588                                  DBUS_TYPE_STRING, service_name,
00589                                  DBUS_TYPE_UINT32, flags,
00590                                  DBUS_TYPE_INVALID))
00591     {
00592       dbus_message_unref (message);
00593       _DBUS_SET_OOM (error);
00594       return -1;
00595     }
00596   
00597   reply = dbus_connection_send_with_reply_and_block (connection, message, -1,
00598                                                      error);
00599   
00600   dbus_message_unref (message);
00601   
00602   if (reply == NULL)
00603     {
00604       _DBUS_ASSERT_ERROR_IS_SET (error);
00605       return -1;
00606     }  
00607 
00608   if (dbus_set_error_from_message (error, reply))
00609     {
00610       _DBUS_ASSERT_ERROR_IS_SET (error);
00611       dbus_message_unref (reply);
00612       return -1;
00613     }
00614   
00615   if (!dbus_message_get_args (reply, error,
00616                               DBUS_TYPE_UINT32, &service_result,
00617                               DBUS_TYPE_INVALID))
00618     {
00619       _DBUS_ASSERT_ERROR_IS_SET (error);
00620       dbus_message_unref (reply);
00621       return -1;
00622     }
00623 
00624   dbus_message_unref (reply);
00625   
00626   return service_result;
00627 }
00628 
00639 dbus_bool_t
00640 dbus_bus_service_exists (DBusConnection *connection,
00641                          const char     *service_name,
00642                          DBusError      *error)
00643 {
00644   DBusMessage *message, *reply;
00645   unsigned int exists;
00646 
00647   _dbus_return_val_if_fail (connection != NULL, FALSE);
00648   _dbus_return_val_if_fail (service_name != NULL, FALSE);
00649   _dbus_return_val_if_error_is_set (error, FALSE);
00650   
00651   message = dbus_message_new_method_call (DBUS_SERVICE_ORG_FREEDESKTOP_DBUS,
00652                                           DBUS_PATH_ORG_FREEDESKTOP_DBUS,
00653                                           DBUS_INTERFACE_ORG_FREEDESKTOP_DBUS,
00654                                           "ServiceExists");
00655   if (message == NULL)
00656     {
00657       _DBUS_SET_OOM (error);
00658       return FALSE;
00659     }
00660   
00661   if (!dbus_message_append_args (message,
00662                                  DBUS_TYPE_STRING, service_name,
00663                                  DBUS_TYPE_INVALID))
00664     {
00665       dbus_message_unref (message);
00666       _DBUS_SET_OOM (error);
00667       return FALSE;
00668     }
00669   
00670   reply = dbus_connection_send_with_reply_and_block (connection, message, -1, error);
00671   dbus_message_unref (message);
00672 
00673   if (reply == NULL)
00674     {
00675       _DBUS_ASSERT_ERROR_IS_SET (error);
00676       return FALSE;
00677     }
00678 
00679   if (!dbus_message_get_args (reply, error,
00680                               DBUS_TYPE_UINT32, &exists,
00681                               DBUS_TYPE_INVALID))
00682     {
00683       _DBUS_ASSERT_ERROR_IS_SET (error);
00684       return FALSE;
00685     }
00686   
00687   return (exists != FALSE);
00688 }
00689 
00705 dbus_bool_t
00706 dbus_bus_activate_service (DBusConnection *connection,
00707                            const char     *service_name,
00708                            dbus_uint32_t   flags,
00709                            dbus_uint32_t  *result,
00710                            DBusError      *error)
00711 {
00712   DBusMessage *msg;
00713   DBusMessage *reply;
00714 
00715   msg = dbus_message_new_method_call (DBUS_SERVICE_ORG_FREEDESKTOP_DBUS,
00716                                       DBUS_PATH_ORG_FREEDESKTOP_DBUS,
00717                                       DBUS_INTERFACE_ORG_FREEDESKTOP_DBUS,
00718                                       "ActivateService");
00719 
00720   if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, service_name,
00721                                  DBUS_TYPE_UINT32, flags, DBUS_TYPE_INVALID))
00722     {
00723       dbus_message_unref (msg);
00724       _DBUS_SET_OOM (error);
00725       return FALSE;
00726     }
00727 
00728   reply = dbus_connection_send_with_reply_and_block (connection, msg,
00729                                                      -1, error);
00730   dbus_message_unref (msg);
00731 
00732   if (reply == NULL)
00733     {
00734       _DBUS_ASSERT_ERROR_IS_SET (error);
00735       return FALSE;
00736     }
00737 
00738   if (dbus_set_error_from_message (error, reply))
00739     {
00740       _DBUS_ASSERT_ERROR_IS_SET (error);
00741       dbus_message_unref (reply);
00742       return FALSE;
00743     }
00744 
00745   if (result != NULL &&
00746       !dbus_message_get_args (reply, error, DBUS_TYPE_UINT32,
00747                               result, DBUS_TYPE_INVALID))
00748     {
00749       _DBUS_ASSERT_ERROR_IS_SET (error);
00750       dbus_message_unref (reply);
00751       return FALSE;
00752     }
00753   
00754   dbus_message_unref (reply);
00755   return TRUE;
00756 }
00757 
00758 static void
00759 send_no_return_values (DBusConnection *connection,
00760                        DBusMessage    *msg,
00761                        DBusError      *error)
00762 {
00763   if (error)
00764     {
00765       /* Block to check success codepath */
00766       DBusMessage *reply;
00767       
00768       reply = dbus_connection_send_with_reply_and_block (connection, msg,
00769                                                          -1, error);
00770       
00771       if (reply == NULL)
00772         {
00773           _DBUS_ASSERT_ERROR_IS_SET (error);
00774           return;
00775         }
00776 
00777       if (dbus_set_error_from_message (error, reply))
00778         {
00779           _DBUS_ASSERT_ERROR_IS_SET (error);
00780           dbus_message_unref (reply);
00781           return;
00782         }
00783 
00784       dbus_message_unref (reply);
00785     }
00786   else
00787     {
00788       /* Silently-fail nonblocking codepath */
00789       if (!dbus_connection_send (connection, msg, NULL))
00790         return;
00791     }
00792 }
00793 
00816 void
00817 dbus_bus_add_match (DBusConnection *connection,
00818                     const char     *rule,
00819                     DBusError      *error)
00820 {
00821   DBusMessage *msg;
00822 
00823   msg = dbus_message_new_method_call (DBUS_SERVICE_ORG_FREEDESKTOP_DBUS,
00824                                       DBUS_PATH_ORG_FREEDESKTOP_DBUS,
00825                                       DBUS_INTERFACE_ORG_FREEDESKTOP_DBUS,
00826                                       "AddMatch");
00827 
00828   if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, rule,
00829                                  DBUS_TYPE_INVALID))
00830     {
00831       dbus_message_unref (msg);
00832       _DBUS_SET_OOM (error);
00833       return;
00834     }
00835 
00836   send_no_return_values (connection, msg, error);
00837 
00838   dbus_message_unref (msg);
00839 }
00840 
00854 void
00855 dbus_bus_remove_match (DBusConnection *connection,
00856                        const char     *rule,
00857                        DBusError      *error)
00858 {
00859   DBusMessage *msg;
00860 
00861   msg = dbus_message_new_method_call (DBUS_SERVICE_ORG_FREEDESKTOP_DBUS,
00862                                       DBUS_PATH_ORG_FREEDESKTOP_DBUS,
00863                                       DBUS_INTERFACE_ORG_FREEDESKTOP_DBUS,
00864                                       "RemoveMatch");
00865 
00866   if (!dbus_message_append_args (msg, DBUS_TYPE_STRING, rule,
00867                                  DBUS_TYPE_INVALID))
00868     {
00869       dbus_message_unref (msg);
00870       _DBUS_SET_OOM (error);
00871       return;
00872     }
00873 
00874   send_no_return_values (connection, msg, error);
00875 
00876   dbus_message_unref (msg);
00877 }
00878 

Generated on Tue Feb 10 18:14:01 2004 for D-BUS by doxygen 1.3.5