code.delx.au - pulseaudio/blob - polyp/polyplib-context.c

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of polypaudio.
   5
   6   polypaudio is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License as published
   8   by the Free Software Foundation; either version 2 of the License,
   9   or (at your option) any later version.
  10
  11   polypaudio is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with polypaudio; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19   USA.
  20 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <stdio.h>
  27 #include <assert.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <sys/types.h>
  31 #include <sys/socket.h>
  32 #include <netdb.h>
  33 #include <unistd.h>
  34 #include <sys/stat.h>
  35 #include <errno.h>
  36 #include <sys/wait.h>
  37
  38 #include "polyplib-internal.h"
  39 #include "polyplib-context.h"
  40 #include "native-common.h"
  41 #include "pdispatch.h"
  42 #include "pstream.h"
  43 #include "dynarray.h"
  44 #include "socket-client.h"
  45 #include "pstream-util.h"
  46 #include "authkey.h"
  47 #include "util.h"
  48 #include "xmalloc.h"
  49 #include "log.h"
  50
  51 static const struct pa_pdispatch_command command_table[PA_COMMAND_MAX] = {
  52     [PA_COMMAND_REQUEST] = { pa_command_request },
  53     [PA_COMMAND_PLAYBACK_STREAM_KILLED] = { pa_command_stream_killed },
  54     [PA_COMMAND_RECORD_STREAM_KILLED] = { pa_command_stream_killed },
  55     [PA_COMMAND_SUBSCRIBE_EVENT] = { pa_command_subscribe_event },
  56 };
  57
  58 struct pa_context *pa_context_new(struct pa_mainloop_api *mainloop, const char *name) {
  59     struct pa_context *c;
  60     assert(mainloop && name);
  61
  62     c = pa_xmalloc(sizeof(struct pa_context));
  63     c->ref = 1;
  64     c->name = pa_xstrdup(name);
  65     c->mainloop = mainloop;
  66     c->client = NULL;
  67     c->pstream = NULL;
  68     c->pdispatch = NULL;
  69     c->playback_streams = pa_dynarray_new();
  70     c->record_streams = pa_dynarray_new();
  71     assert(c->playback_streams && c->record_streams);
  72
  73     PA_LLIST_HEAD_INIT(struct pa_stream, c->streams);
  74     PA_LLIST_HEAD_INIT(struct pa_operation, c->operations);
  75
  76     c->error = PA_ERROR_OK;
  77     c->state = PA_CONTEXT_UNCONNECTED;
  78     c->ctag = 0;
  79
  80     c->state_callback = NULL;
  81     c->state_userdata = NULL;
  82
  83     c->subscribe_callback = NULL;
  84     c->subscribe_userdata = NULL;
  85
  86     c->memblock_stat = pa_memblock_stat_new();
  87
  88     pa_check_for_sigpipe();
  89     return c;
  90 }
  91
  92 static void context_free(struct pa_context *c) {
  93     assert(c);
  94
  95     while (c->operations)
  96         pa_operation_cancel(c->operations);
  97
  98     while (c->streams)
  99         pa_stream_set_state(c->streams, PA_STREAM_TERMINATED);
 100
 101     if (c->client)
 102         pa_socket_client_unref(c->client);
 103     if (c->pdispatch)
 104         pa_pdispatch_unref(c->pdispatch);
 105     if (c->pstream) {
 106         pa_pstream_close(c->pstream);
 107         pa_pstream_unref(c->pstream);
 108     }
 109
 110     if (c->record_streams)
 111         pa_dynarray_free(c->record_streams, NULL, NULL);
 112     if (c->playback_streams)
 113         pa_dynarray_free(c->playback_streams, NULL, NULL);
 114
 115     pa_memblock_stat_unref(c->memblock_stat);
 116
 117     pa_xfree(c->name);
 118     pa_xfree(c);
 119 }
 120
 121 struct pa_context* pa_context_ref(struct pa_context *c) {
 122     assert(c && c->ref >= 1);
 123     c->ref++;
 124     return c;
 125 }
 126
 127 void pa_context_unref(struct pa_context *c) {
 128     assert(c && c->ref >= 1);
 129
 130     if ((--(c->ref)) == 0)
 131         context_free(c);
 132 }
 133
 134 void pa_context_set_state(struct pa_context *c, enum pa_context_state st) {
 135     assert(c);
 136
 137     if (c->state == st)
 138         return;
 139
 140     pa_context_ref(c);
 141
 142     if (st == PA_CONTEXT_FAILED || st == PA_CONTEXT_TERMINATED) {
 143         struct pa_stream *s;
 144
 145         s = c->streams ? pa_stream_ref(c->streams) : NULL;
 146         while (s) {
 147             struct pa_stream *n = s->next ? pa_stream_ref(s->next) : NULL;
 148             pa_stream_set_state(s, st == PA_CONTEXT_FAILED ? PA_STREAM_FAILED : PA_STREAM_TERMINATED);
 149             pa_stream_unref(s);
 150             s = n;
 151         }
 152
 153         if (c->pdispatch)
 154             pa_pdispatch_unref(c->pdispatch);
 155         c->pdispatch = NULL;
 156
 157         if (c->pstream) {
 158             pa_pstream_close(c->pstream);
 159             pa_pstream_unref(c->pstream);
 160         }
 161         c->pstream = NULL;
 162
 163         if (c->client)
 164             pa_socket_client_unref(c->client);
 165         c->client = NULL;
 166     }
 167
 168     c->state = st;
 169     if (c->state_callback)
 170         c->state_callback(c, c->state_userdata);
 171
 172     pa_context_unref(c);
 173 }
 174
 175 void pa_context_fail(struct pa_context *c, int error) {
 176     assert(c);
 177     c->error = error;
 178     pa_context_set_state(c, PA_CONTEXT_FAILED);
 179 }
 180
 181 static void pstream_die_callback(struct pa_pstream *p, void *userdata) {
 182     struct pa_context *c = userdata;
 183     assert(p && c);
 184     pa_context_fail(c, PA_ERROR_CONNECTIONTERMINATED);
 185 }
 186
 187 static void pstream_packet_callback(struct pa_pstream *p, struct pa_packet *packet, void *userdata) {
 188     struct pa_context *c = userdata;
 189     assert(p && packet && c);
 190
 191     pa_context_ref(c);
 192
 193     if (pa_pdispatch_run(c->pdispatch, packet, c) < 0) {
 194         pa_log(__FILE__": invalid packet.\n");
 195         pa_context_fail(c, PA_ERROR_PROTOCOL);
 196     }
 197
 198     pa_context_unref(c);
 199 }
 200
 201 static void pstream_memblock_callback(struct pa_pstream *p, uint32_t channel, uint32_t delta, const struct pa_memchunk *chunk, void *userdata) {
 202     struct pa_context *c = userdata;
 203     struct pa_stream *s;
 204     assert(p && chunk && c && chunk->memblock && chunk->memblock->data);
 205
 206     pa_context_ref(c);
 207
 208     if ((s = pa_dynarray_get(c->record_streams, channel))) {
 209         if (s->read_callback)
 210             s->read_callback(s, (uint8_t*) chunk->memblock->data + chunk->index, chunk->length, s->read_userdata);
 211     }
 212
 213     pa_context_unref(c);
 214 }
 215
 216 int pa_context_handle_error(struct pa_context *c, uint32_t command, struct pa_tagstruct *t) {
 217     assert(c && t);
 218
 219     if (command == PA_COMMAND_ERROR) {
 220         if (pa_tagstruct_getu32(t, &c->error) < 0) {
 221             pa_context_fail(c, PA_ERROR_PROTOCOL);
 222             return -1;
 223
 224         }
 225     } else if (command == PA_COMMAND_TIMEOUT)
 226         c->error = PA_ERROR_TIMEOUT;
 227     else {
 228         pa_context_fail(c, PA_ERROR_PROTOCOL);
 229         return -1;
 230     }
 231
 232     return 0;
 233 }
 234
 235 static void setup_complete_callback(struct pa_pdispatch *pd, uint32_t command, uint32_t tag, struct pa_tagstruct *t, void *userdata) {
 236     struct pa_context *c = userdata;
 237     assert(pd && c && (c->state == PA_CONTEXT_AUTHORIZING || c->state == PA_CONTEXT_SETTING_NAME));
 238
 239     pa_context_ref(c);
 240
 241     if (command != PA_COMMAND_REPLY) {
 242
 243         if (pa_context_handle_error(c, command, t) < 0)
 244             pa_context_fail(c, PA_ERROR_PROTOCOL);
 245
 246         pa_context_fail(c, c->error);
 247         goto finish;
 248     }
 249
 250     switch(c->state) {
 251         case PA_CONTEXT_AUTHORIZING: {
 252             struct pa_tagstruct *t;
 253             t = pa_tagstruct_new(NULL, 0);
 254             assert(t);
 255             pa_tagstruct_putu32(t, PA_COMMAND_SET_NAME);
 256             pa_tagstruct_putu32(t, tag = c->ctag++);
 257             pa_tagstruct_puts(t, c->name);
 258             pa_pstream_send_tagstruct(c->pstream, t);
 259             pa_pdispatch_register_reply(c->pdispatch, tag, DEFAULT_TIMEOUT, setup_complete_callback, c);
 260
 261             pa_context_set_state(c, PA_CONTEXT_SETTING_NAME);
 262             break;
 263         }
 264
 265         case PA_CONTEXT_SETTING_NAME :
 266             pa_context_set_state(c, PA_CONTEXT_READY);
 267             break;
 268
 269         default:
 270             assert(0);
 271     }
 272
 273 finish:
 274     pa_context_unref(c);
 275 }
 276
 277 static void setup_context(struct pa_context *c, struct pa_iochannel *io) {
 278     struct pa_tagstruct *t;
 279     uint32_t tag;
 280     assert(c && io);
 281
 282     pa_context_ref(c);
 283
 284     assert(!c->pstream);
 285     c->pstream = pa_pstream_new(c->mainloop, io, c->memblock_stat);
 286     assert(c->pstream);
 287
 288     pa_pstream_set_die_callback(c->pstream, pstream_die_callback, c);
 289     pa_pstream_set_recieve_packet_callback(c->pstream, pstream_packet_callback, c);
 290     pa_pstream_set_recieve_memblock_callback(c->pstream, pstream_memblock_callback, c);
 291
 292     assert(!c->pdispatch);
 293     c->pdispatch = pa_pdispatch_new(c->mainloop, command_table, PA_COMMAND_MAX);
 294     assert(c->pdispatch);
 295
 296     if (pa_authkey_load_from_home(PA_NATIVE_COOKIE_FILE, c->auth_cookie, sizeof(c->auth_cookie)) < 0) {
 297         pa_context_fail(c, PA_ERROR_AUTHKEY);
 298         goto finish;
 299     }
 300
 301     t = pa_tagstruct_new(NULL, 0);
 302     assert(t);
 303     pa_tagstruct_putu32(t, PA_COMMAND_AUTH);
 304     pa_tagstruct_putu32(t, tag = c->ctag++);
 305     pa_tagstruct_put_arbitrary(t, c->auth_cookie, sizeof(c->auth_cookie));
 306     pa_pstream_send_tagstruct(c->pstream, t);
 307     pa_pdispatch_register_reply(c->pdispatch, tag, DEFAULT_TIMEOUT, setup_complete_callback, c);
 308
 309     pa_context_set_state(c, PA_CONTEXT_AUTHORIZING);
 310
 311 finish:
 312
 313     pa_context_unref(c);
 314 }
 315
 316 static void on_connection(struct pa_socket_client *client, struct pa_iochannel*io, void *userdata) {
 317     struct pa_context *c = userdata;
 318     assert(client && c && c->state == PA_CONTEXT_CONNECTING);
 319
 320     pa_context_ref(c);
 321
 322     pa_socket_client_unref(client);
 323     c->client = NULL;
 324
 325     if (!io) {
 326         pa_context_fail(c, PA_ERROR_CONNECTIONREFUSED);
 327         goto finish;
 328     }
 329
 330     setup_context(c, io);
 331
 332 finish:
 333     pa_context_unref(c);
 334 }
 335
 336 static struct sockaddr *resolve_server(const char *server, size_t *len) {
 337     struct sockaddr *sa;
 338     struct addrinfo hints, *result = NULL;
 339     char *port, host[256];
 340     assert(server && len);
 341
 342     snprintf(host, sizeof(host), "%s", server);
 343     host[strcspn(host, ":")] = 0;
 344
 345     if ((port = strrchr(server, ':')))
 346         port++;
 347
 348     if (!port)
 349         port = DEFAULT_PORT;
 350
 351     memset(&hints, 0, sizeof(hints));
 352     hints.ai_family = PF_UNSPEC;
 353     hints.ai_socktype = SOCK_STREAM;
 354     hints.ai_protocol = 0;
 355
 356     if (getaddrinfo(host, port, &hints, &result) != 0)
 357         return NULL;
 358     assert(result);
 359
 360     sa = pa_xmalloc(*len = result->ai_addrlen);
 361     memcpy(sa, result->ai_addr, *len);
 362
 363     freeaddrinfo(result);
 364
 365     return sa;
 366 }
 367
 368 int pa_context_connect(struct pa_context *c, const char *server) {
 369     int r = -1;
 370     assert(c && c->ref >= 1 && c->state == PA_CONTEXT_UNCONNECTED);
 371
 372     pa_context_ref(c);
 373
 374     if (!server)
 375         if (!(server = getenv(ENV_DEFAULT_SERVER)))
 376             server = DEFAULT_SERVER;
 377
 378     assert(!c->client);
 379
 380     if (*server == '/') {
 381         if (!(c->client = pa_socket_client_new_unix(c->mainloop, server))) {
 382             pa_context_fail(c, PA_ERROR_CONNECTIONREFUSED);
 383             goto finish;
 384         }
 385     } else {
 386         struct sockaddr* sa;
 387         size_t sa_len;
 388
 389         if (!(sa = resolve_server(server, &sa_len))) {
 390             pa_context_fail(c, PA_ERROR_INVALIDSERVER);
 391             goto finish;
 392         }
 393
 394         c->client = pa_socket_client_new_sockaddr(c->mainloop, sa, sa_len);
 395         pa_xfree(sa);
 396
 397         if (!c->client) {
 398             pa_context_fail(c, PA_ERROR_CONNECTIONREFUSED);
 399             goto finish;
 400         }
 401     }
 402
 403     pa_socket_client_set_callback(c->client, on_connection, c);
 404     pa_context_set_state(c, PA_CONTEXT_CONNECTING);
 405
 406     r = 0;
 407
 408 finish:
 409     pa_context_unref(c);
 410
 411     return r;
 412 }
 413
 414 void pa_context_disconnect(struct pa_context *c) {
 415     assert(c);
 416     pa_context_set_state(c, PA_CONTEXT_TERMINATED);
 417 }
 418
 419 enum pa_context_state pa_context_get_state(struct pa_context *c) {
 420     assert(c && c->ref >= 1);
 421     return c->state;
 422 }
 423
 424 int pa_context_errno(struct pa_context *c) {
 425     assert(c && c->ref >= 1);
 426     return c->error;
 427 }
 428
 429 void pa_context_set_state_callback(struct pa_context *c, void (*cb)(struct pa_context *c, void *userdata), void *userdata) {
 430     assert(c && c->ref >= 1);
 431     c->state_callback = cb;
 432     c->state_userdata = userdata;
 433 }
 434
 435 int pa_context_is_pending(struct pa_context *c) {
 436     assert(c && c->ref >= 1);
 437
 438 /*     pa_log("pstream: %i\n", pa_pstream_is_pending(c->pstream)); */
 439 /*     pa_log("pdispatch: %i\n", pa_pdispatch_is_pending(c->pdispatch)); */
 440
 441     return (c->pstream && pa_pstream_is_pending(c->pstream)) || (c->pdispatch && pa_pdispatch_is_pending(c->pdispatch)) || c->client;
 442 }
 443
 444 static void set_dispatch_callbacks(struct pa_operation *o);
 445
 446 static void pdispatch_drain_callback(struct pa_pdispatch*pd, void *userdata) {
 447     set_dispatch_callbacks(userdata);
 448 }
 449
 450 static void pstream_drain_callback(struct pa_pstream *s, void *userdata) {
 451     set_dispatch_callbacks(userdata);
 452 }
 453
 454 static void set_dispatch_callbacks(struct pa_operation *o) {
 455     int done = 1;
 456     assert(o && o->context && o->context->ref >= 1 && o->ref >= 1 && o->context->state == PA_CONTEXT_READY);
 457
 458     pa_pstream_set_drain_callback(o->context->pstream, NULL, NULL);
 459     pa_pdispatch_set_drain_callback(o->context->pdispatch, NULL, NULL);
 460
 461     if (pa_pdispatch_is_pending(o->context->pdispatch)) {
 462         pa_pdispatch_set_drain_callback(o->context->pdispatch, pdispatch_drain_callback, o);
 463         done = 0;
 464     }
 465
 466     if (pa_pstream_is_pending(o->context->pstream)) {
 467         pa_pstream_set_drain_callback(o->context->pstream, pstream_drain_callback, o);
 468         done = 0;
 469     }
 470
 471     if (!done)
 472         pa_operation_ref(o);
 473     else {
 474         if (o->callback) {
 475             void (*cb)(struct pa_context *c, void *userdata);
 476             cb = (void (*)(struct pa_context*, void*)) o->callback;
 477             cb(o->context, o->userdata);
 478         }
 479
 480         pa_operation_done(o);
 481     }
 482
 483     pa_operation_unref(o);
 484 }
 485
 486 struct pa_operation* pa_context_drain(struct pa_context *c, void (*cb) (struct pa_context*c, void *userdata), void *userdata) {
 487     struct pa_operation *o;
 488     assert(c && c->ref >= 1);
 489
 490     if (c->state != PA_CONTEXT_READY)
 491         return NULL;
 492
 493     if (!pa_context_is_pending(c))
 494         return NULL;
 495
 496     o = pa_operation_new(c, NULL);
 497     assert(o);
 498     o->callback = cb;
 499     o->userdata = userdata;
 500
 501     set_dispatch_callbacks(pa_operation_ref(o));
 502
 503     return o;
 504 }
 505
 506 void pa_context_exit_daemon(struct pa_context *c) {
 507     struct pa_tagstruct *t;
 508     assert(c && c->ref >= 1);
 509
 510     t = pa_tagstruct_new(NULL, 0);
 511     assert(t);
 512     pa_tagstruct_putu32(t, PA_COMMAND_EXIT);
 513     pa_tagstruct_putu32(t, c->ctag++);
 514     pa_pstream_send_tagstruct(c->pstream, t);
 515 }
 516
 517 void pa_context_simple_ack_callback(struct pa_pdispatch *pd, uint32_t command, uint32_t tag, struct pa_tagstruct *t, void *userdata) {
 518     struct pa_operation *o = userdata;
 519     int success = 1;
 520     assert(pd && o && o->context && o->ref >= 1);
 521
 522     if (command != PA_COMMAND_REPLY) {
 523         if (pa_context_handle_error(o->context, command, t) < 0)
 524             goto finish;
 525
 526         success = 0;
 527     } else if (!pa_tagstruct_eof(t)) {
 528         pa_context_fail(o->context, PA_ERROR_PROTOCOL);
 529         goto finish;
 530     }
 531
 532     if (o->callback) {
 533         void (*cb)(struct pa_context *c, int success, void *userdata) = o->callback;
 534         cb(o->context, success, o->userdata);
 535     }
 536
 537 finish:
 538     pa_operation_done(o);
 539     pa_operation_unref(o);
 540 }
 541
 542 struct pa_operation* pa_context_send_simple_command(struct pa_context *c, uint32_t command, void (*internal_callback)(struct pa_pdispatch *pd, uint32_t command, uint32_t tag, struct pa_tagstruct *t, void *userdata), void (*cb)(), void *userdata) {
 543     struct pa_tagstruct *t;
 544     struct pa_operation *o;
 545     uint32_t tag;
 546     assert(c && cb);
 547
 548     o = pa_operation_new(c, NULL);
 549     o->callback = cb;
 550     o->userdata = userdata;
 551
 552     t = pa_tagstruct_new(NULL, 0);
 553     pa_tagstruct_putu32(t, command);
 554     pa_tagstruct_putu32(t, tag = c->ctag++);
 555     pa_pstream_send_tagstruct(c->pstream, t);
 556     pa_pdispatch_register_reply(c->pdispatch, tag, DEFAULT_TIMEOUT, internal_callback, o);
 557
 558     return pa_operation_ref(o);
 559 }
 560
 561 const char* pa_get_library_version(void) {
 562     return PACKAGE_VERSION;
 563 }
 564
 565 static int is_running(void) {
 566     struct stat st;
 567
 568     if (DEFAULT_SERVER[0] != '/')
 569         return 1;
 570
 571     if (stat(DEFAULT_SERVER, &st) < 0)
 572         return 0;
 573
 574     return 1;
 575 }
 576
 577 int pa_context_connect_spawn(struct pa_context *c, void (*atfork)(void), void (*prefork)(void), void (*postfork)(void)) {
 578     pid_t pid;
 579     int status, r;
 580     int fds[2] = { -1, -1} ;
 581     struct pa_iochannel *io;
 582
 583     if (getenv(ENV_DEFAULT_SERVER) || is_running())
 584         return pa_context_connect(c, NULL);
 585
 586     if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds) < 0) {
 587         pa_log(__FILE__": socketpair() failed: %s\n", strerror(errno));
 588         pa_context_fail(c, PA_ERROR_INTERNAL);
 589         goto fail;
 590     }
 591
 592     if (prefork)
 593         prefork();
 594
 595     if ((pid = fork()) < 0) {
 596         pa_log(__FILE__": fork() failed: %s\n", strerror(errno));
 597         pa_context_fail(c, PA_ERROR_INTERNAL);
 598
 599         if (postfork)
 600             postfork();
 601
 602         goto fail;
 603     } else if (!pid) {
 604         char t[64];
 605         char *p;
 606         /* Child */
 607
 608         close(fds[0]);
 609
 610         if (atfork)
 611             atfork();
 612
 613         if (!(p = getenv(ENV_DEFAULT_BINARY)))
 614             p = POLYPAUDIO_BINARY;
 615
 616         snprintf(t, sizeof(t), "-Lmodule-native-protocol-fd fd=%i", fds[1]);
 617         execl(p, p, "-r", "-D", "-lsyslog", "-X 5", t, NULL);
 618
 619         exit(1);
 620     }
 621
 622     /* Parent */
 623
 624     r = waitpid(pid, &status, 0);
 625
 626     if (postfork)
 627         postfork();
 628
 629     if (r < 0) {
 630         pa_log(__FILE__": waitpid() failed: %s\n", strerror(errno));
 631         pa_context_fail(c, PA_ERROR_INTERNAL);
 632         goto fail;
 633     } else if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
 634         pa_context_fail(c, PA_ERROR_CONNECTIONREFUSED);
 635         goto fail;
 636     }
 637
 638     close(fds[1]);
 639
 640     io = pa_iochannel_new(c->mainloop, fds[0], fds[0]);
 641     setup_context(c, io);
 642     return 0;
 643
 644 fail:
 645     if (fds[0] != -1)
 646         close(fds[0]);
 647     if (fds[1] != -1)
 648         close(fds[1]);
 649
 650     return -1;
 651 }
 652
 653 struct pa_operation* pa_context_set_default_sink(struct pa_context *c, const char *name, void(*cb)(struct pa_context*c, int success, void *userdata), void *userdata) {
 654     struct pa_tagstruct *t;
 655     struct pa_operation *o;
 656     uint32_t tag;
 657     assert(c && cb);
 658
 659     o = pa_operation_new(c, NULL);
 660     o->callback = cb;
 661     o->userdata = userdata;
 662
 663     t = pa_tagstruct_new(NULL, 0);
 664     pa_tagstruct_putu32(t, PA_COMMAND_SET_DEFAULT_SINK);
 665     pa_tagstruct_putu32(t, tag = c->ctag++);
 666     pa_tagstruct_puts(t, name);
 667     pa_pstream_send_tagstruct(c->pstream, t);
 668     pa_pdispatch_register_reply(c->pdispatch, tag, DEFAULT_TIMEOUT,  pa_context_simple_ack_callback, o);
 669
 670     return pa_operation_ref(o);
 671 }
 672
 673 struct pa_operation* pa_context_set_default_source(struct pa_context *c, const char *name, void(*cb)(struct pa_context*c, int success,  void *userdata), void *userdata) {
 674     struct pa_tagstruct *t;
 675     struct pa_operation *o;
 676     uint32_t tag;
 677     assert(c && cb);
 678
 679     o = pa_operation_new(c, NULL);
 680     o->callback = cb;
 681     o->userdata = userdata;
 682
 683     t = pa_tagstruct_new(NULL, 0);
 684     pa_tagstruct_putu32(t, PA_COMMAND_SET_DEFAULT_SOURCE);
 685     pa_tagstruct_putu32(t, tag = c->ctag++);
 686     pa_tagstruct_puts(t, name);
 687     pa_pstream_send_tagstruct(c->pstream, t);
 688     pa_pdispatch_register_reply(c->pdispatch, tag, DEFAULT_TIMEOUT,  pa_context_simple_ack_callback, o);
 689
 690     return pa_operation_ref(o);
 691 }