summaryrefslogtreecommitdiff
path: root/server/sbus/sssd_dbus_connection.c
blob: 38ccc6ab13443b3a5e2e5ec6d9e56ac7a1c2f7f3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
/*
    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 "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_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(9, ("dbus conn: %lX\n", dbus_conn));

    if (conn->retries > 0) {
        DEBUG(6, ("SBUS is reconnecting. Deferring.\n"));
        /* Currently trying to reconnect, defer dispatch */
        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(5,("Adding connection %lX\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(5, ("Invoking default destructor on connection %lX\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(5,("Disconnecting %lX\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(5,("Disconnected %lX\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;
}

void sbus_conn_send_reply(struct sbus_connection *conn, DBusMessage *reply)
{
    dbus_connection_send(conn->dbus.conn, reply, NULL);
}