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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 <sys/select.h>
  34 #include <errno.h>
  35
  36 #include "xcb.h"
  37 #include "xcbext.h"
  38 #include "xcbint.h"
  39
  40 #define XCB_ERROR 0
  41 #define XCB_REPLY 1
  42 #define XCB_XGE_EVENT 35
  43
  44 struct event_list {
  45     xcb_generic_event_t *event;
  46     struct event_list *next;
  47 };
  48
  49 struct reply_list {
  50     void *reply;
  51     struct reply_list *next;
  52 };
  53
  54 typedef struct pending_reply {
  55     uint64_t first_request;
  56     uint64_t last_request;
  57     enum workarounds workaround;
  58     int flags;
  59     struct pending_reply *next;
  60 } pending_reply;
  61
  62 typedef struct reader_list {
  63     unsigned int request;
  64     pthread_cond_t *data;
  65     struct reader_list *next;
  66 } reader_list;
  67
  68 static void wake_up_next_reader(xcb_connection_t *c)
  69 {
  70     int pthreadret;
  71     if(c->in.readers)
  72         pthreadret = pthread_cond_signal(c->in.readers->data);
  73     else
  74         pthreadret = pthread_cond_signal(&c->in.event_cond);
  75     assert(pthreadret == 0);
  76 }
  77
  78 static int read_packet(xcb_connection_t *c)
  79 {
  80     xcb_generic_reply_t genrep;
  81     int length = 32;
  82     int eventlength = 0; /* length after first 32 bytes for GenericEvents */
  83     void *buf;
  84     pending_reply *pend = 0;
  85     struct event_list *event;
  86
  87     /* Wait for there to be enough data for us to read a whole packet */
  88     if(c->in.queue_len < length)
  89         return 0;
  90
  91     /* Get the response type, length, and sequence number. */
  92     memcpy(&genrep, c->in.queue, sizeof(genrep));
  93
  94     /* Compute 32-bit sequence number of this packet. */
  95     if((genrep.response_type & 0x7f) != XCB_KEYMAP_NOTIFY)
  96     {
  97         uint64_t lastread = c->in.request_read;
  98         c->in.request_read = (lastread & UINT64_C(0xffffffffffff0000)) | genrep.sequence;
  99         if(XCB_SEQUENCE_COMPARE(c->in.request_read, <, lastread))
 100             c->in.request_read += 0x10000;
 101         if(XCB_SEQUENCE_COMPARE(c->in.request_read, >, c->in.request_expected))
 102             c->in.request_expected = c->in.request_read;
 103
 104         if(c->in.request_read != lastread)
 105         {
 106             if(c->in.current_reply)
 107             {
 108                 _xcb_map_put(c->in.replies, lastread, c->in.current_reply);
 109                 c->in.current_reply = 0;
 110                 c->in.current_reply_tail = &c->in.current_reply;
 111             }
 112             c->in.request_completed = c->in.request_read - 1;
 113         }
 114
 115         while(c->in.pending_replies &&
 116               c->in.pending_replies->workaround != WORKAROUND_EXTERNAL_SOCKET_OWNER &&
 117               XCB_SEQUENCE_COMPARE (c->in.pending_replies->last_request, <=, c->in.request_completed))
 118         {
 119             pending_reply *oldpend = c->in.pending_replies;
 120             c->in.pending_replies = oldpend->next;
 121             if(!oldpend->next)
 122                 c->in.pending_replies_tail = &c->in.pending_replies;
 123             free(oldpend);
 124         }
 125
 126         if(genrep.response_type == XCB_ERROR)
 127             c->in.request_completed = c->in.request_read;
 128     }
 129
 130     if(genrep.response_type == XCB_ERROR || genrep.response_type == XCB_REPLY)
 131     {
 132         pend = c->in.pending_replies;
 133         if(pend &&
 134            !(XCB_SEQUENCE_COMPARE(pend->first_request, <=, c->in.request_read) &&
 135              (pend->workaround == WORKAROUND_EXTERNAL_SOCKET_OWNER ||
 136               XCB_SEQUENCE_COMPARE(c->in.request_read, <=, pend->last_request))))
 137             pend = 0;
 138     }
 139
 140     /* For reply packets, check that the entire packet is available. */
 141     if(genrep.response_type == XCB_REPLY)
 142     {
 143         if(pend && pend->workaround == WORKAROUND_GLX_GET_FB_CONFIGS_BUG)
 144         {
 145             uint32_t *p = (uint32_t *) c->in.queue;
 146             genrep.length = p[2] * p[3] * 2;
 147         }
 148         length += genrep.length * 4;
 149     }
 150
 151     /* XGE events may have sizes > 32 */
 152     if (genrep.response_type == XCB_XGE_EVENT)
 153     {
 154         eventlength = ((xcb_ge_event_t*)&genrep)->length * 4;
 155     }
 156
 157     buf = malloc(length + eventlength +
 158             (genrep.response_type == XCB_REPLY ? 0 : sizeof(uint32_t)));
 159     if(!buf)
 160     {
 161         _xcb_conn_shutdown(c);
 162         return 0;
 163     }
 164
 165     if(_xcb_in_read_block(c, buf, length) <= 0)
 166     {
 167         free(buf);
 168         return 0;
 169     }
 170
 171     /* pull in XGE event data if available, append after event struct */
 172     if (eventlength)
 173     {
 174         if(_xcb_in_read_block(c, &((xcb_generic_event_t*)buf)[1], eventlength) <= 0)
 175         {
 176             free(buf);
 177             return 0;
 178         }
 179     }
 180
 181     if(pend && (pend->flags & XCB_REQUEST_DISCARD_REPLY))
 182     {
 183         free(buf);
 184         return 1;
 185     }
 186
 187     if(genrep.response_type != XCB_REPLY)
 188         ((xcb_generic_event_t *) buf)->full_sequence = c->in.request_read;
 189
 190     /* reply, or checked error */
 191     if( genrep.response_type == XCB_REPLY ||
 192        (genrep.response_type == XCB_ERROR && pend && (pend->flags & XCB_REQUEST_CHECKED)))
 193     {
 194         reader_list *reader;
 195         struct reply_list *cur = malloc(sizeof(struct reply_list));
 196         if(!cur)
 197         {
 198             _xcb_conn_shutdown(c);
 199             free(buf);
 200             return 0;
 201         }
 202         cur->reply = buf;
 203         cur->next = 0;
 204         *c->in.current_reply_tail = cur;
 205         c->in.current_reply_tail = &cur->next;
 206         for(reader = c->in.readers;
 207             reader &&
 208             XCB_SEQUENCE_COMPARE_32(reader->request, <=, c->in.request_read);
 209             reader = reader->next)
 210         {
 211             if(XCB_SEQUENCE_COMPARE_32(reader->request, ==, c->in.request_read))
 212             {
 213                 pthread_cond_signal(reader->data);
 214                 break;
 215             }
 216         }
 217         return 1;
 218     }
 219
 220     /* event, or unchecked error */
 221     event = malloc(sizeof(struct event_list));
 222     if(!event)
 223     {
 224         _xcb_conn_shutdown(c);
 225         free(buf);
 226         return 0;
 227     }
 228     event->event = buf;
 229     event->next = 0;
 230     *c->in.events_tail = event;
 231     c->in.events_tail = &event->next;
 232     pthread_cond_signal(&c->in.event_cond);
 233     return 1; /* I have something for you... */
 234 }
 235
 236 static xcb_generic_event_t *get_event(xcb_connection_t *c)
 237 {
 238     struct event_list *cur = c->in.events;
 239     xcb_generic_event_t *ret;
 240     if(!c->in.events)
 241         return 0;
 242     ret = cur->event;
 243     c->in.events = cur->next;
 244     if(!cur->next)
 245         c->in.events_tail = &c->in.events;
 246     free(cur);
 247     return ret;
 248 }
 249
 250 static void free_reply_list(struct reply_list *head)
 251 {
 252     while(head)
 253     {
 254         struct reply_list *cur = head;
 255         head = cur->next;
 256         free(cur->reply);
 257         free(cur);
 258     }
 259 }
 260
 261 static int read_block(const int fd, void *buf, const ssize_t len)
 262 {
 263     int done = 0;
 264     while(done < len)
 265     {
 266         int ret = read(fd, ((char *) buf) + done, len - done);
 267         if(ret > 0)
 268             done += ret;
 269         if(ret < 0 && errno == EAGAIN)
 270         {
 271             fd_set fds;
 272             FD_ZERO(&fds);
 273             FD_SET(fd, &fds);
 274             do {
 275                 ret = select(fd + 1, &fds, 0, 0, 0);
 276             } while (ret == -1 && errno == EINTR);
 277         }
 278         if(ret <= 0)
 279             return ret;
 280     }
 281     return len;
 282 }
 283
 284 static int poll_for_reply(xcb_connection_t *c, unsigned int request, void **reply, xcb_generic_error_t **error)
 285 {
 286     struct reply_list *head;
 287
 288     /* If an error occurred when issuing the request, fail immediately. */
 289     if(!request)
 290         head = 0;
 291     /* We've read requests past the one we want, so if it has replies we have
 292      * them all and they're in the replies map. */
 293     else if(XCB_SEQUENCE_COMPARE_32(request, <, c->in.request_read))
 294     {
 295         head = _xcb_map_remove(c->in.replies, request);
 296         if(head && head->next)
 297             _xcb_map_put(c->in.replies, request, head->next);
 298     }
 299     /* We're currently processing the responses to the request we want, and we
 300      * have a reply ready to return. So just return it without blocking. */
 301     else if(XCB_SEQUENCE_COMPARE_32(request, ==, c->in.request_read) && c->in.current_reply)
 302     {
 303         head = c->in.current_reply;
 304         c->in.current_reply = head->next;
 305         if(!head->next)
 306             c->in.current_reply_tail = &c->in.current_reply;
 307     }
 308     /* We know this request can't have any more replies, and we've already
 309      * established it doesn't have a reply now. Don't bother blocking. */
 310     else if(XCB_SEQUENCE_COMPARE_32(request, ==, c->in.request_completed))
 311         head = 0;
 312     /* We may have more replies on the way for this request: block until we're
 313      * sure. */
 314     else
 315         return 0;
 316
 317     if(error)
 318         *error = 0;
 319     *reply = 0;
 320
 321     if(head)
 322     {
 323         if(((xcb_generic_reply_t *) head->reply)->response_type == XCB_ERROR)
 324         {
 325             if(error)
 326                 *error = head->reply;
 327             else
 328                 free(head->reply);
 329         }
 330         else
 331             *reply = head->reply;
 332
 333         free(head);
 334     }
 335
 336     return 1;
 337 }
 338
 339 /* Public interface */
 340
 341 void *xcb_wait_for_reply(xcb_connection_t *c, unsigned int request, xcb_generic_error_t **e)
 342 {
 343     uint64_t widened_request;
 344     void *ret = 0;
 345     if(e)
 346         *e = 0;
 347     if(c->has_error)
 348         return 0;
 349
 350     pthread_mutex_lock(&c->iolock);
 351
 352     widened_request = (c->out.request & UINT64_C(0xffffffff00000000)) | request;
 353     if(widened_request > c->out.request)
 354         widened_request -= UINT64_C(1) << 32;
 355
 356     /* If this request has not been written yet, write it. */
 357     if(c->out.return_socket || _xcb_out_flush_to(c, widened_request))
 358     {
 359         pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
 360         reader_list reader;
 361         reader_list **prev_reader;
 362
 363         for(prev_reader = &c->in.readers;
 364             *prev_reader &&
 365             XCB_SEQUENCE_COMPARE_32((*prev_reader)->request, <=, request);
 366             prev_reader = &(*prev_reader)->next)
 367         {
 368             /* empty */;
 369         }
 370         reader.request = request;
 371         reader.data = &cond;
 372         reader.next = *prev_reader;
 373         *prev_reader = &reader;
 374
 375         while(!poll_for_reply(c, request, &ret, e))
 376             if(!_xcb_conn_wait(c, &cond, 0, 0))
 377                 break;
 378
 379         for(prev_reader = &c->in.readers;
 380             *prev_reader &&
 381             XCB_SEQUENCE_COMPARE_32((*prev_reader)->request, <=, request);
 382             prev_reader = &(*prev_reader)->next)
 383         {
 384             if(*prev_reader == &reader)
 385             {
 386                 *prev_reader = (*prev_reader)->next;
 387                 break;
 388             }
 389         }
 390         pthread_cond_destroy(&cond);
 391     }
 392
 393     wake_up_next_reader(c);
 394     pthread_mutex_unlock(&c->iolock);
 395     return ret;
 396 }
 397
 398 int xcb_poll_for_reply(xcb_connection_t *c, unsigned int request, void **reply, xcb_generic_error_t **error)
 399 {
 400     int ret;
 401     if(c->has_error)
 402     {
 403         *reply = 0;
 404         if(error)
 405             *error = 0;
 406         return 1; /* would not block */
 407     }
 408     assert(reply != 0);
 409     pthread_mutex_lock(&c->iolock);
 410     ret = poll_for_reply(c, request, reply, error);
 411     pthread_mutex_unlock(&c->iolock);
 412     return ret;
 413 }
 414
 415 xcb_generic_event_t *xcb_wait_for_event(xcb_connection_t *c)
 416 {
 417     xcb_generic_event_t *ret;
 418     if(c->has_error)
 419         return 0;
 420     pthread_mutex_lock(&c->iolock);
 421     /* get_event returns 0 on empty list. */
 422     while(!(ret = get_event(c)))
 423         if(!_xcb_conn_wait(c, &c->in.event_cond, 0, 0))
 424             break;
 425
 426     wake_up_next_reader(c);
 427     pthread_mutex_unlock(&c->iolock);
 428     return ret;
 429 }
 430
 431 xcb_generic_event_t *xcb_poll_for_event(xcb_connection_t *c)
 432 {
 433     xcb_generic_event_t *ret = 0;
 434     if(!c->has_error)
 435     {
 436         pthread_mutex_lock(&c->iolock);
 437         /* FIXME: follow X meets Z architecture changes. */
 438         ret = get_event(c);
 439         if(!ret && _xcb_in_read(c)) /* _xcb_in_read shuts down the connection on error */
 440             ret = get_event(c);
 441         pthread_mutex_unlock(&c->iolock);
 442     }
 443     return ret;
 444 }
 445
 446 xcb_generic_error_t *xcb_request_check(xcb_connection_t *c, xcb_void_cookie_t cookie)
 447 {
 448     /* FIXME: this could hold the lock to avoid syncing unnecessarily, but
 449      * that would require factoring the locking out of xcb_get_input_focus,
 450      * xcb_get_input_focus_reply, and xcb_wait_for_reply. */
 451     xcb_generic_error_t *ret;
 452     void *reply;
 453     if(c->has_error)
 454         return 0;
 455     if(XCB_SEQUENCE_COMPARE_32(cookie.sequence,>,c->in.request_expected)
 456        && XCB_SEQUENCE_COMPARE_32(cookie.sequence,>,c->in.request_completed))
 457     {
 458         free(xcb_get_input_focus_reply(c, xcb_get_input_focus(c), &ret));
 459         assert(!ret);
 460     }
 461     reply = xcb_wait_for_reply(c, cookie.sequence, &ret);
 462     assert(!reply);
 463     return ret;
 464 }
 465
 466 /* Private interface */
 467
 468 int _xcb_in_init(_xcb_in *in)
 469 {
 470     if(pthread_cond_init(&in->event_cond, 0))
 471         return 0;
 472     in->reading = 0;
 473
 474     in->queue_len = 0;
 475
 476     in->request_read = 0;
 477     in->request_completed = 0;
 478
 479     in->replies = _xcb_map_new();
 480     if(!in->replies)
 481         return 0;
 482
 483     in->current_reply_tail = &in->current_reply;
 484     in->events_tail = &in->events;
 485     in->pending_replies_tail = &in->pending_replies;
 486
 487     return 1;
 488 }
 489
 490 void _xcb_in_destroy(_xcb_in *in)
 491 {
 492     pthread_cond_destroy(&in->event_cond);
 493     free_reply_list(in->current_reply);
 494     _xcb_map_delete(in->replies, (void (*)(void *)) free_reply_list);
 495     while(in->events)
 496     {
 497         struct event_list *e = in->events;
 498         in->events = e->next;
 499         free(e->event);
 500         free(e);
 501     }
 502     while(in->pending_replies)
 503     {
 504         pending_reply *pend = in->pending_replies;
 505         in->pending_replies = pend->next;
 506         free(pend);
 507     }
 508 }
 509
 510 int _xcb_in_expect_reply(xcb_connection_t *c, uint64_t request, enum workarounds workaround, int flags)
 511 {
 512     pending_reply *pend = malloc(sizeof(pending_reply));
 513     assert(workaround != WORKAROUND_NONE || flags != 0);
 514     if(!pend)
 515     {
 516         _xcb_conn_shutdown(c);
 517         return 0;
 518     }
 519     pend->first_request = pend->last_request = request;
 520     pend->workaround = workaround;
 521     pend->flags = flags;
 522     pend->next = 0;
 523     *c->in.pending_replies_tail = pend;
 524     c->in.pending_replies_tail = &pend->next;
 525     return 1;
 526 }
 527
 528 void _xcb_in_replies_done(xcb_connection_t *c)
 529 {
 530     struct pending_reply *pend;
 531     if (c->in.pending_replies_tail != &c->in.pending_replies)
 532     {
 533         pend = container_of(c->in.pending_replies_tail, struct pending_reply, next);
 534         if(pend->workaround == WORKAROUND_EXTERNAL_SOCKET_OWNER)
 535         {
 536             pend->last_request = c->out.request;
 537             pend->workaround = WORKAROUND_NONE;
 538         }
 539     }
 540 }
 541
 542 int _xcb_in_read(xcb_connection_t *c)
 543 {
 544     int n = read(c->fd, c->in.queue + c->in.queue_len, sizeof(c->in.queue) - c->in.queue_len);
 545     if(n > 0)
 546         c->in.queue_len += n;
 547     while(read_packet(c))
 548         /* empty */;
 549     if((n > 0) || (n < 0 && errno == EAGAIN))
 550         return 1;
 551     _xcb_conn_shutdown(c);
 552     return 0;
 553 }
 554
 555 int _xcb_in_read_block(xcb_connection_t *c, void *buf, int len)
 556 {
 557     int done = c->in.queue_len;
 558     if(len < done)
 559         done = len;
 560
 561     memcpy(buf, c->in.queue, done);
 562     c->in.queue_len -= done;
 563     memmove(c->in.queue, c->in.queue + done, c->in.queue_len);
 564
 565     if(len > done)
 566     {
 567         int ret = read_block(c->fd, (char *) buf + done, len - done);
 568         if(ret <= 0)
 569         {
 570             _xcb_conn_shutdown(c);
 571             return ret;
 572         }
 573     }
 574
 575     return len;
 576 }