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   1 /* Copyright (C) 2001-2004 Bart Massey and Jamey Sharp.
   2  *
   3  * Permission is hereby granted, free of charge, to any person obtaining a
   4  * copy of this software and associated documentation files (the "Software"),
   5  * to deal in the Software without restriction, including without limitation
   6  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   7  * and/or sell copies of the Software, and to permit persons to whom the
   8  * Software is furnished to do so, subject to the following conditions:
   9  *
  10  * The above copyright notice and this permission notice shall be included in
  11  * all copies or substantial portions of the Software.
  12  *
  13  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  14  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  15  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  16  * AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  17  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  18  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  19  *
  20  * Except as contained in this notice, the names of the authors or their
  21  * institutions shall not be used in advertising or otherwise to promote the
  22  * sale, use or other dealings in this Software without prior written
  23  * authorization from the authors.
  24  */
  25
  26 /* Stuff that reads stuff from the server. */
  27
  28 #include <assert.h>
  29 #include <string.h>
  30 #include <stdlib.h>
  31 #include <unistd.h>
  32 #include <stdio.h>
  33 #include <errno.h>
  34
  35 #include "xcb.h"
  36 #include "xcbext.h"
  37 #include "xcbint.h"
  38 #if USE_POLL
  39 #include <poll.h>
  40 #endif
  41 #ifndef _WIN32
  42 #include <sys/select.h>
  43 #include <sys/socket.h>
  44 #endif
  45
  46 #ifdef _WIN32
  47 #include "xcb_windefs.h"
  48 #endif /* _WIN32 */
  49
  50 #define XCB_ERROR 0
  51 #define XCB_REPLY 1
  52 #define XCB_XGE_EVENT 35
  53
  54 /* required for compiling for Win32 using MinGW */
  55 #ifndef MSG_WAITALL
  56 #define MSG_WAITALL 0
  57 #endif
  58
  59 struct event_list {
  60     xcb_generic_event_t *event;
  61     struct event_list *next;
  62 };
  63
  64 struct reply_list {
  65     void *reply;
  66     struct reply_list *next;
  67 };
  68
  69 typedef struct pending_reply {
  70     uint64_t first_request;
  71     uint64_t last_request;
  72     enum workarounds workaround;
  73     int flags;
  74     struct pending_reply *next;
  75 } pending_reply;
  76
  77 typedef struct reader_list {
  78     unsigned int request;
  79     pthread_cond_t *data;
  80     struct reader_list *next;
  81 } reader_list;
  82
  83 static int read_packet(xcb_connection_t *c)
  84 {
  85     xcb_generic_reply_t genrep;
  86     int length = 32;
  87     int eventlength = 0; /* length after first 32 bytes for GenericEvents */
  88     void *buf;
  89     pending_reply *pend = 0;
  90     struct event_list *event;
  91
  92     /* Wait for there to be enough data for us to read a whole packet */
  93     if(c->in.queue_len < length)
  94         return 0;
  95
  96     /* Get the response type, length, and sequence number. */
  97     memcpy(&genrep, c->in.queue, sizeof(genrep));
  98
  99     /* Compute 32-bit sequence number of this packet. */
 100     if((genrep.response_type & 0x7f) != XCB_KEYMAP_NOTIFY)
 101     {
 102         uint64_t lastread = c->in.request_read;
 103         c->in.request_read = (lastread & UINT64_C(0xffffffffffff0000)) | genrep.sequence;
 104         if(XCB_SEQUENCE_COMPARE(c->in.request_read, <, lastread))
 105             c->in.request_read += 0x10000;
 106         if(XCB_SEQUENCE_COMPARE(c->in.request_read, >, c->in.request_expected))
 107             c->in.request_expected = c->in.request_read;
 108
 109         if(c->in.request_read != lastread)
 110         {
 111             if(c->in.current_reply)
 112             {
 113                 _xcb_map_put(c->in.replies, lastread, c->in.current_reply);
 114                 c->in.current_reply = 0;
 115                 c->in.current_reply_tail = &c->in.current_reply;
 116             }
 117             c->in.request_completed = c->in.request_read - 1;
 118         }
 119
 120         while(c->in.pending_replies &&
 121               c->in.pending_replies->workaround != WORKAROUND_EXTERNAL_SOCKET_OWNER &&
 122               XCB_SEQUENCE_COMPARE (c->in.pending_replies->last_request, <=, c->in.request_completed))
 123         {
 124             pending_reply *oldpend = c->in.pending_replies;
 125             c->in.pending_replies = oldpend->next;
 126             if(!oldpend->next)
 127                 c->in.pending_replies_tail = &c->in.pending_replies;
 128             free(oldpend);
 129         }
 130
 131         if(genrep.response_type == XCB_ERROR)
 132             c->in.request_completed = c->in.request_read;
 133     }
 134
 135     if(genrep.response_type == XCB_ERROR || genrep.response_type == XCB_REPLY)
 136     {
 137         pend = c->in.pending_replies;
 138         if(pend &&
 139            !(XCB_SEQUENCE_COMPARE(pend->first_request, <=, c->in.request_read) &&
 140              (pend->workaround == WORKAROUND_EXTERNAL_SOCKET_OWNER ||
 141               XCB_SEQUENCE_COMPARE(c->in.request_read, <=, pend->last_request))))
 142             pend = 0;
 143     }
 144
 145     /* For reply packets, check that the entire packet is available. */
 146     if(genrep.response_type == XCB_REPLY)
 147     {
 148         if(pend && pend->workaround == WORKAROUND_GLX_GET_FB_CONFIGS_BUG)
 149         {
 150             uint32_t *p = (uint32_t *) c->in.queue;
 151             genrep.length = p[2] * p[3] * 2;
 152         }
 153         length += genrep.length * 4;
 154     }
 155
 156     /* XGE events may have sizes > 32 */
 157     if (genrep.response_type == XCB_XGE_EVENT)
 158         eventlength = genrep.length * 4;
 159
 160     buf = malloc(length + eventlength +
 161             (genrep.response_type == XCB_REPLY ? 0 : sizeof(uint32_t)));
 162     if(!buf)
 163     {
 164         _xcb_conn_shutdown(c);
 165         return 0;
 166     }
 167
 168     if(_xcb_in_read_block(c, buf, length) <= 0)
 169     {
 170         free(buf);
 171         return 0;
 172     }
 173
 174     /* pull in XGE event data if available, append after event struct */
 175     if (eventlength)
 176     {
 177         if(_xcb_in_read_block(c, &((xcb_generic_event_t*)buf)[1], eventlength) <= 0)
 178         {
 179             free(buf);
 180             return 0;
 181         }
 182     }
 183
 184     if(pend && (pend->flags & XCB_REQUEST_DISCARD_REPLY))
 185     {
 186         free(buf);
 187         return 1;
 188     }
 189
 190     if(genrep.response_type != XCB_REPLY)
 191         ((xcb_generic_event_t *) buf)->full_sequence = c->in.request_read;
 192
 193     /* reply, or checked error */
 194     if( genrep.response_type == XCB_REPLY ||
 195        (genrep.response_type == XCB_ERROR && pend && (pend->flags & XCB_REQUEST_CHECKED)))
 196     {
 197         reader_list *reader;
 198         struct reply_list *cur = malloc(sizeof(struct reply_list));
 199         if(!cur)
 200         {
 201             _xcb_conn_shutdown(c);
 202             free(buf);
 203             return 0;
 204         }
 205         cur->reply = buf;
 206         cur->next = 0;
 207         *c->in.current_reply_tail = cur;
 208         c->in.current_reply_tail = &cur->next;
 209         for(reader = c->in.readers;
 210             reader &&
 211             XCB_SEQUENCE_COMPARE_32(reader->request, <=, c->in.request_read);
 212             reader = reader->next)
 213         {
 214             if(XCB_SEQUENCE_COMPARE_32(reader->request, ==, c->in.request_read))
 215             {
 216                 pthread_cond_signal(reader->data);
 217                 break;
 218             }
 219         }
 220         return 1;
 221     }
 222
 223     /* event, or unchecked error */
 224     event = malloc(sizeof(struct event_list));
 225     if(!event)
 226     {
 227         _xcb_conn_shutdown(c);
 228         free(buf);
 229         return 0;
 230     }
 231     event->event = buf;
 232     event->next = 0;
 233     *c->in.events_tail = event;
 234     c->in.events_tail = &event->next;
 235     pthread_cond_signal(&c->in.event_cond);
 236     return 1; /* I have something for you... */
 237 }
 238
 239 static xcb_generic_event_t *get_event(xcb_connection_t *c)
 240 {
 241     struct event_list *cur = c->in.events;
 242     xcb_generic_event_t *ret;
 243     if(!c->in.events)
 244         return 0;
 245     ret = cur->event;
 246     c->in.events = cur->next;
 247     if(!cur->next)
 248         c->in.events_tail = &c->in.events;
 249     free(cur);
 250     return ret;
 251 }
 252
 253 static void free_reply_list(struct reply_list *head)
 254 {
 255     while(head)
 256     {
 257         struct reply_list *cur = head;
 258         head = cur->next;
 259         free(cur->reply);
 260         free(cur);
 261     }
 262 }
 263
 264 static int read_block(const int fd, void *buf, const ssize_t len)
 265 {
 266     int done = 0;
 267     while(done < len)
 268     {
 269         int ret = recv(fd, ((char *) buf) + done, len - done,MSG_WAITALL);
 270         if(ret > 0)
 271             done += ret;
 272 #ifndef _WIN32
 273         if(ret < 0 && errno == EAGAIN)
 274 #else
 275         if(ret == SOCKET_ERROR && WSAGetLastError() == WSAEWOULDBLOCK)
 276 #endif /* !_Win32 */
 277         {
 278 #if USE_POLL
 279             struct pollfd pfd;
 280             pfd.fd = fd;
 281             pfd.events = POLLIN;
 282             pfd.revents = 0;
 283             do {
 284                 ret = poll(&pfd, 1, -1);
 285             } while (ret == -1 && errno == EINTR);
 286 #else
 287             fd_set fds;
 288             FD_ZERO(&fds);
 289             FD_SET(fd, &fds);
 290
 291             /* Initializing errno here makes sure that for Win32 this loop will execute only once */
 292             errno = 0;
 293             do {
 294                 ret = select(fd + 1, &fds, 0, 0, 0);
 295             } while (ret == -1 && errno == EINTR);
 296 #endif /* USE_POLL */
 297         }
 298         if(ret <= 0)
 299             return ret;
 300     }
 301     return len;
 302 }
 303
 304 static int poll_for_reply(xcb_connection_t *c, unsigned int request, void **reply, xcb_generic_error_t **error)
 305 {
 306     struct reply_list *head;
 307
 308     /* If an error occurred when issuing the request, fail immediately. */
 309     if(!request)
 310         head = 0;
 311     /* We've read requests past the one we want, so if it has replies we have
 312      * them all and they're in the replies map. */
 313     else if(XCB_SEQUENCE_COMPARE_32(request, <, c->in.request_read))
 314     {
 315         head = _xcb_map_remove(c->in.replies, request);
 316         if(head && head->next)
 317             _xcb_map_put(c->in.replies, request, head->next);
 318     }
 319     /* We're currently processing the responses to the request we want, and we
 320      * have a reply ready to return. So just return it without blocking. */
 321     else if(XCB_SEQUENCE_COMPARE_32(request, ==, c->in.request_read) && c->in.current_reply)
 322     {
 323         head = c->in.current_reply;
 324         c->in.current_reply = head->next;
 325         if(!head->next)
 326             c->in.current_reply_tail = &c->in.current_reply;
 327     }
 328     /* We know this request can't have any more replies, and we've already
 329      * established it doesn't have a reply now. Don't bother blocking. */
 330     else if(XCB_SEQUENCE_COMPARE_32(request, ==, c->in.request_completed))
 331         head = 0;
 332     /* We may have more replies on the way for this request: block until we're
 333      * sure. */
 334     else
 335         return 0;
 336
 337     if(error)
 338         *error = 0;
 339     *reply = 0;
 340
 341     if(head)
 342     {
 343         if(((xcb_generic_reply_t *) head->reply)->response_type == XCB_ERROR)
 344         {
 345             if(error)
 346                 *error = head->reply;
 347             else
 348                 free(head->reply);
 349         }
 350         else
 351             *reply = head->reply;
 352
 353         free(head);
 354     }
 355
 356     return 1;
 357 }
 358
 359 static void *wait_for_reply(xcb_connection_t *c, unsigned int request, xcb_generic_error_t **e)
 360 {
 361     void *ret = 0;
 362     uint64_t widened_request = (c->out.request & UINT64_C(0xffffffff00000000)) | request;
 363     if(widened_request > c->out.request)
 364         widened_request -= UINT64_C(1) << 32;
 365
 366     /* If this request has not been written yet, write it. */
 367     if(c->out.return_socket || _xcb_out_flush_to(c, widened_request))
 368     {
 369         pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
 370         reader_list reader;
 371         reader_list **prev_reader;
 372
 373         for(prev_reader = &c->in.readers;
 374             *prev_reader &&
 375             XCB_SEQUENCE_COMPARE_32((*prev_reader)->request, <=, request);
 376             prev_reader = &(*prev_reader)->next)
 377         {
 378             /* empty */;
 379         }
 380         reader.request = request;
 381         reader.data = &cond;
 382         reader.next = *prev_reader;
 383         *prev_reader = &reader;
 384
 385         while(!poll_for_reply(c, request, &ret, e))
 386             if(!_xcb_conn_wait(c, &cond, 0, 0))
 387                 break;
 388
 389         for(prev_reader = &c->in.readers;
 390             *prev_reader &&
 391             XCB_SEQUENCE_COMPARE_32((*prev_reader)->request, <=, request);
 392             prev_reader = &(*prev_reader)->next)
 393         {
 394             if(*prev_reader == &reader)
 395             {
 396                 *prev_reader = (*prev_reader)->next;
 397                 break;
 398             }
 399         }
 400         pthread_cond_destroy(&cond);
 401     }
 402
 403     _xcb_in_wake_up_next_reader(c);
 404     return ret;
 405 }
 406
 407 /* Public interface */
 408
 409 void *xcb_wait_for_reply(xcb_connection_t *c, unsigned int request, xcb_generic_error_t **e)
 410 {
 411     void *ret;
 412     if(e)
 413         *e = 0;
 414     if(c->has_error)
 415         return 0;
 416
 417     pthread_mutex_lock(&c->iolock);
 418     ret = wait_for_reply(c, request, e);
 419     pthread_mutex_unlock(&c->iolock);
 420     return ret;
 421 }
 422
 423 static void insert_pending_discard(xcb_connection_t *c, pending_reply **prev_next, uint64_t seq)
 424 {
 425     pending_reply *pend;
 426     pend = malloc(sizeof(*pend));
 427     if(!pend)
 428     {
 429         _xcb_conn_shutdown(c);
 430         return;
 431     }
 432
 433     pend->first_request = seq;
 434     pend->last_request = seq;
 435     pend->workaround = 0;
 436     pend->flags = XCB_REQUEST_DISCARD_REPLY;
 437     pend->next = *prev_next;
 438     *prev_next = pend;
 439
 440     if(!pend->next)
 441         c->in.pending_replies_tail = &pend->next;
 442 }
 443
 444 static void discard_reply(xcb_connection_t *c, unsigned int request)
 445 {
 446     void *reply;
 447     pending_reply **prev_pend;
 448     uint64_t widened_request;
 449
 450     /* Free any replies or errors that we've already read. Stop if
 451      * xcb_wait_for_reply would block or we've run out of replies. */
 452     while(poll_for_reply(c, request, &reply, 0) && reply)
 453         free(reply);
 454
 455     /* If we've proven there are no more responses coming, we're done. */
 456     if(XCB_SEQUENCE_COMPARE_32(request, <=, c->in.request_completed))
 457         return;
 458
 459     /* Walk the list of pending requests. Mark the first match for deletion. */
 460     for(prev_pend = &c->in.pending_replies; *prev_pend; prev_pend = &(*prev_pend)->next)
 461     {
 462         if(XCB_SEQUENCE_COMPARE_32((*prev_pend)->first_request, >, request))
 463             break;
 464
 465         if(XCB_SEQUENCE_COMPARE_32((*prev_pend)->first_request, ==, request))
 466         {
 467             /* Pending reply found. Mark for discard: */
 468             (*prev_pend)->flags |= XCB_REQUEST_DISCARD_REPLY;
 469             return;
 470         }
 471     }
 472
 473     /* Pending reply not found (likely due to _unchecked request). Create one: */
 474     widened_request = (c->out.request & UINT64_C(0xffffffff00000000)) | request;
 475     if(widened_request > c->out.request)
 476         widened_request -= UINT64_C(1) << 32;
 477
 478     insert_pending_discard(c, prev_pend, widened_request);
 479 }
 480
 481 void xcb_discard_reply(xcb_connection_t *c, unsigned int sequence)
 482 {
 483     if(c->has_error)
 484         return;
 485
 486     /* If an error occurred when issuing the request, fail immediately. */
 487     if(!sequence)
 488         return;
 489
 490     pthread_mutex_lock(&c->iolock);
 491     discard_reply(c, sequence);
 492     pthread_mutex_unlock(&c->iolock);
 493 }
 494
 495 int xcb_poll_for_reply(xcb_connection_t *c, unsigned int request, void **reply, xcb_generic_error_t **error)
 496 {
 497     int ret;
 498     if(c->has_error)
 499     {
 500         *reply = 0;
 501         if(error)
 502             *error = 0;
 503         return 1; /* would not block */
 504     }
 505     assert(reply != 0);
 506     pthread_mutex_lock(&c->iolock);
 507     ret = poll_for_reply(c, request, reply, error);
 508     pthread_mutex_unlock(&c->iolock);
 509     return ret;
 510 }
 511
 512 xcb_generic_event_t *xcb_wait_for_event(xcb_connection_t *c)
 513 {
 514     xcb_generic_event_t *ret;
 515     if(c->has_error)
 516         return 0;
 517     pthread_mutex_lock(&c->iolock);
 518     /* get_event returns 0 on empty list. */
 519     while(!(ret = get_event(c)))
 520         if(!_xcb_conn_wait(c, &c->in.event_cond, 0, 0))
 521             break;
 522
 523     _xcb_in_wake_up_next_reader(c);
 524     pthread_mutex_unlock(&c->iolock);
 525     return ret;
 526 }
 527
 528 xcb_generic_event_t *xcb_poll_for_event(xcb_connection_t *c)
 529 {
 530     xcb_generic_event_t *ret = 0;
 531     if(!c->has_error)
 532     {
 533         pthread_mutex_lock(&c->iolock);
 534         /* FIXME: follow X meets Z architecture changes. */
 535         ret = get_event(c);
 536         if(!ret && _xcb_in_read(c)) /* _xcb_in_read shuts down the connection on error */
 537             ret = get_event(c);
 538         pthread_mutex_unlock(&c->iolock);
 539     }
 540     return ret;
 541 }
 542
 543 xcb_generic_error_t *xcb_request_check(xcb_connection_t *c, xcb_void_cookie_t cookie)
 544 {
 545     xcb_generic_error_t *ret = 0;
 546     void *reply;
 547     if(c->has_error)
 548         return 0;
 549     pthread_mutex_lock(&c->iolock);
 550     if(XCB_SEQUENCE_COMPARE_32(cookie.sequence,>=,c->in.request_expected)
 551        && XCB_SEQUENCE_COMPARE_32(cookie.sequence,>,c->in.request_completed))
 552     {
 553         _xcb_out_send_sync(c);
 554         _xcb_out_flush_to(c, c->out.request);
 555     }
 556     reply = wait_for_reply(c, cookie.sequence, &ret);
 557     assert(!reply);
 558     pthread_mutex_unlock(&c->iolock);
 559     return ret;
 560 }
 561
 562 /* Private interface */
 563
 564 int _xcb_in_init(_xcb_in *in)
 565 {
 566     if(pthread_cond_init(&in->event_cond, 0))
 567         return 0;
 568     in->reading = 0;
 569
 570     in->queue_len = 0;
 571
 572     in->request_read = 0;
 573     in->request_completed = 0;
 574
 575     in->replies = _xcb_map_new();
 576     if(!in->replies)
 577         return 0;
 578
 579     in->current_reply_tail = &in->current_reply;
 580     in->events_tail = &in->events;
 581     in->pending_replies_tail = &in->pending_replies;
 582
 583     return 1;
 584 }
 585
 586 void _xcb_in_destroy(_xcb_in *in)
 587 {
 588     pthread_cond_destroy(&in->event_cond);
 589     free_reply_list(in->current_reply);
 590     _xcb_map_delete(in->replies, (void (*)(void *)) free_reply_list);
 591     while(in->events)
 592     {
 593         struct event_list *e = in->events;
 594         in->events = e->next;
 595         free(e->event);
 596         free(e);
 597     }
 598     while(in->pending_replies)
 599     {
 600         pending_reply *pend = in->pending_replies;
 601         in->pending_replies = pend->next;
 602         free(pend);
 603     }
 604 }
 605
 606 void _xcb_in_wake_up_next_reader(xcb_connection_t *c)
 607 {
 608     int pthreadret;
 609     if(c->in.readers)
 610         pthreadret = pthread_cond_signal(c->in.readers->data);
 611     else
 612         pthreadret = pthread_cond_signal(&c->in.event_cond);
 613     assert(pthreadret == 0);
 614 }
 615
 616 int _xcb_in_expect_reply(xcb_connection_t *c, uint64_t request, enum workarounds workaround, int flags)
 617 {
 618     pending_reply *pend = malloc(sizeof(pending_reply));
 619     assert(workaround != WORKAROUND_NONE || flags != 0);
 620     if(!pend)
 621     {
 622         _xcb_conn_shutdown(c);
 623         return 0;
 624     }
 625     pend->first_request = pend->last_request = request;
 626     pend->workaround = workaround;
 627     pend->flags = flags;
 628     pend->next = 0;
 629     *c->in.pending_replies_tail = pend;
 630     c->in.pending_replies_tail = &pend->next;
 631     return 1;
 632 }
 633
 634 void _xcb_in_replies_done(xcb_connection_t *c)
 635 {
 636     struct pending_reply *pend;
 637     if (c->in.pending_replies_tail != &c->in.pending_replies)
 638     {
 639         pend = container_of(c->in.pending_replies_tail, struct pending_reply, next);
 640         if(pend->workaround == WORKAROUND_EXTERNAL_SOCKET_OWNER)
 641         {
 642             pend->last_request = c->out.request;
 643             pend->workaround = WORKAROUND_NONE;
 644         }
 645     }
 646 }
 647
 648 int _xcb_in_read(xcb_connection_t *c)
 649 {
 650     int n = recv(c->fd, c->in.queue + c->in.queue_len, sizeof(c->in.queue) - c->in.queue_len,MSG_WAITALL);
 651     if(n > 0)
 652         c->in.queue_len += n;
 653     while(read_packet(c))
 654         /* empty */;
 655 #ifndef _WIN32
 656     if((n > 0) || (n < 0 && errno == EAGAIN))
 657 #else
 658     if((n > 0) || (n < 0 && WSAGetLastError() == WSAEWOULDBLOCK))
 659 #endif /* !_WIN32 */
 660         return 1;
 661     _xcb_conn_shutdown(c);
 662     return 0;
 663 }
 664
 665 int _xcb_in_read_block(xcb_connection_t *c, void *buf, int len)
 666 {
 667     int done = c->in.queue_len;
 668     if(len < done)
 669         done = len;
 670
 671     memcpy(buf, c->in.queue, done);
 672     c->in.queue_len -= done;
 673     memmove(c->in.queue, c->in.queue + done, c->in.queue_len);
 674
 675     if(len > done)
 676     {
 677         int ret = read_block(c->fd, (char *) buf + done, len - done);
 678         if(ret <= 0)
 679         {
 680             _xcb_conn_shutdown(c);
 681             return ret;
 682         }
 683     }
 684
 685     return len;
 686 }