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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
  43 struct event_list {
  44     xcb_generic_event_t *event;
  45     struct event_list *next;
  46 };
  47
  48 struct reply_list {
  49     void *reply;
  50     struct reply_list *next;
  51 };
  52
  53 typedef struct pending_reply {
  54     unsigned int request;
  55     enum workarounds workaround;
  56     int flags;
  57     struct pending_reply *next;
  58 } pending_reply;
  59
  60 typedef struct reader_list {
  61     unsigned int request;
  62     pthread_cond_t *data;
  63     struct reader_list *next;
  64 } reader_list;
  65
  66 static void wake_up_next_reader(xcb_connection_t *c)
  67 {
  68     int pthreadret;
  69     if(c->in.readers)
  70         pthreadret = pthread_cond_signal(c->in.readers->data);
  71     else
  72         pthreadret = pthread_cond_signal(&c->in.event_cond);
  73     assert(pthreadret == 0);
  74 }
  75
  76 static int read_packet(xcb_connection_t *c)
  77 {
  78     xcb_generic_reply_t genrep;
  79     int length = 32;
  80     void *buf;
  81     pending_reply *pend = 0;
  82     struct event_list *event;
  83
  84     /* Wait for there to be enough data for us to read a whole packet */
  85     if(c->in.queue_len < length)
  86         return 0;
  87
  88     /* Get the response type, length, and sequence number. */
  89     memcpy(&genrep, c->in.queue, sizeof(genrep));
  90
  91     /* Compute 32-bit sequence number of this packet. */
  92     if((genrep.response_type & 0x7f) != XCB_KEYMAP_NOTIFY)
  93     {
  94         unsigned int lastread = c->in.request_read;
  95         c->in.request_read = (lastread & 0xffff0000) | genrep.sequence;
  96         if(XCB_SEQUENCE_COMPARE(c->in.request_read, <, lastread))
  97             c->in.request_read += 0x10000;
  98         if(XCB_SEQUENCE_COMPARE(c->in.request_read, >, c->in.request_expected))
  99             c->in.request_expected = c->in.request_read;
 100
 101         if(c->in.request_read != lastread)
 102         {
 103             if(c->in.current_reply)
 104             {
 105                 _xcb_map_put(c->in.replies, lastread, c->in.current_reply);
 106                 c->in.current_reply = 0;
 107                 c->in.current_reply_tail = &c->in.current_reply;
 108             }
 109             c->in.request_completed = c->in.request_read - 1;
 110         }
 111
 112         while(c->in.pending_replies &&
 113               XCB_SEQUENCE_COMPARE (c->in.pending_replies->request, <=, c->in.request_completed))
 114         {
 115             pending_reply *oldpend = c->in.pending_replies;
 116             c->in.pending_replies = oldpend->next;
 117             if(!oldpend->next)
 118                 c->in.pending_replies_tail = &c->in.pending_replies;
 119             free(oldpend);
 120         }
 121
 122         if(genrep.response_type == XCB_ERROR)
 123             c->in.request_completed = c->in.request_read;
 124     }
 125
 126     if(genrep.response_type == XCB_ERROR || genrep.response_type == XCB_REPLY)
 127     {
 128         pend = c->in.pending_replies;
 129         if(pend && pend->request != c->in.request_read)
 130             pend = 0;
 131     }
 132
 133     /* For reply packets, check that the entire packet is available. */
 134     if(genrep.response_type == XCB_REPLY)
 135     {
 136         if(pend && pend->workaround == WORKAROUND_GLX_GET_FB_CONFIGS_BUG)
 137         {
 138             uint32_t *p = (uint32_t *) c->in.queue;
 139             genrep.length = p[2] * p[3] * 2;
 140         }
 141         length += genrep.length * 4;
 142     }
 143
 144     buf = malloc(length + (genrep.response_type == XCB_REPLY ? 0 : sizeof(uint32_t)));
 145     if(!buf)
 146     {
 147         _xcb_conn_shutdown(c);
 148         return 0;
 149     }
 150     if(_xcb_in_read_block(c, buf, length) <= 0)
 151     {
 152         free(buf);
 153         return 0;
 154     }
 155     if(pend && (pend->flags & XCB_REQUEST_DISCARD_REPLY))
 156     {
 157         free(buf);
 158         return 1;
 159     }
 160
 161     if(genrep.response_type != XCB_REPLY)
 162         ((xcb_generic_event_t *) buf)->full_sequence = c->in.request_read;
 163
 164     /* reply, or checked error */
 165     if( genrep.response_type == XCB_REPLY ||
 166        (genrep.response_type == XCB_ERROR && pend && (pend->flags & XCB_REQUEST_CHECKED)))
 167     {
 168         reader_list *reader;
 169         struct reply_list *cur = malloc(sizeof(struct reply_list));
 170         if(!cur)
 171         {
 172             _xcb_conn_shutdown(c);
 173             return 0;
 174         }
 175         cur->reply = buf;
 176         cur->next = 0;
 177         *c->in.current_reply_tail = cur;
 178         c->in.current_reply_tail = &cur->next;
 179         for(reader = c->in.readers;
 180             reader &&
 181             XCB_SEQUENCE_COMPARE(reader->request, <=, c->in.request_read);
 182             reader = reader->next)
 183         {
 184             if(reader->request == c->in.request_read)
 185             {
 186                 pthread_cond_signal(reader->data);
 187                 break;
 188             }
 189         }
 190         return 1;
 191     }
 192
 193     /* event, or unchecked error */
 194     event = malloc(sizeof(struct event_list));
 195     if(!event)
 196     {
 197         _xcb_conn_shutdown(c);
 198         free(buf);
 199         return 0;
 200     }
 201     event->event = buf;
 202     event->next = 0;
 203     *c->in.events_tail = event;
 204     c->in.events_tail = &event->next;
 205     pthread_cond_signal(&c->in.event_cond);
 206     return 1; /* I have something for you... */
 207 }
 208
 209 static xcb_generic_event_t *get_event(xcb_connection_t *c)
 210 {
 211     struct event_list *cur = c->in.events;
 212     xcb_generic_event_t *ret;
 213     if(!c->in.events)
 214         return 0;
 215     ret = cur->event;
 216     c->in.events = cur->next;
 217     if(!cur->next)
 218         c->in.events_tail = &c->in.events;
 219     free(cur);
 220     return ret;
 221 }
 222
 223 static void free_reply_list(struct reply_list *head)
 224 {
 225     while(head)
 226     {
 227         struct reply_list *cur = head;
 228         head = cur->next;
 229         free(cur->reply);
 230         free(cur);
 231     }
 232 }
 233
 234 static int read_block(const int fd, void *buf, const size_t len)
 235 {
 236     int done = 0;
 237     while(done < len)
 238     {
 239         int ret = read(fd, ((char *) buf) + done, len - done);
 240         if(ret > 0)
 241             done += ret;
 242         if(ret < 0 && errno == EAGAIN)
 243         {
 244             fd_set fds;
 245             FD_ZERO(&fds);
 246             FD_SET(fd, &fds);
 247             do {
 248                 ret = select(fd + 1, &fds, 0, 0, 0);
 249             } while (ret == -1 && errno == EINTR);
 250         }
 251         if(ret <= 0)
 252             return ret;
 253     }
 254     return len;
 255 }
 256
 257 static int poll_for_reply(xcb_connection_t *c, unsigned int request, void **reply, xcb_generic_error_t **error)
 258 {
 259     struct reply_list *head;
 260
 261     /* If an error occurred when issuing the request, fail immediately. */
 262     if(!request)
 263         head = 0;
 264     /* We've read requests past the one we want, so if it has replies we have
 265      * them all and they're in the replies map. */
 266     else if(XCB_SEQUENCE_COMPARE(request, <, c->in.request_read))
 267     {
 268         head = _xcb_map_remove(c->in.replies, request);
 269         if(head && head->next)
 270             _xcb_map_put(c->in.replies, request, head->next);
 271     }
 272     /* We're currently processing the responses to the request we want, and we
 273      * have a reply ready to return. So just return it without blocking. */
 274     else if(request == c->in.request_read && c->in.current_reply)
 275     {
 276         head = c->in.current_reply;
 277         c->in.current_reply = head->next;
 278         if(!head->next)
 279             c->in.current_reply_tail = &c->in.current_reply;
 280     }
 281     /* We know this request can't have any more replies, and we've already
 282      * established it doesn't have a reply now. Don't bother blocking. */
 283     else if(request == c->in.request_completed)
 284         head = 0;
 285     /* We may have more replies on the way for this request: block until we're
 286      * sure. */
 287     else
 288         return 0;
 289
 290     if(error)
 291         *error = 0;
 292     *reply = 0;
 293
 294     if(head)
 295     {
 296         if(((xcb_generic_reply_t *) head->reply)->response_type == XCB_ERROR)
 297         {
 298             if(error)
 299                 *error = head->reply;
 300             else
 301                 free(head->reply);
 302         }
 303         else
 304             *reply = head->reply;
 305
 306         free(head);
 307     }
 308
 309     return 1;
 310 }
 311
 312 /* Public interface */
 313
 314 void *xcb_wait_for_reply(xcb_connection_t *c, unsigned int request, xcb_generic_error_t **e)
 315 {
 316     void *ret = 0;
 317     if(e)
 318         *e = 0;
 319     if(c->has_error)
 320         return 0;
 321
 322     _xcb_lock_io(c);
 323
 324     /* If this request has not been written yet, write it. */
 325     if(_xcb_out_flush_to(c, request))
 326     {
 327         pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
 328         reader_list reader;
 329         reader_list **prev_reader;
 330
 331         for(prev_reader = &c->in.readers;
 332             *prev_reader &&
 333             XCB_SEQUENCE_COMPARE ((*prev_reader)->request, <=, request);
 334             prev_reader = &(*prev_reader)->next)
 335         {
 336             /* empty */;
 337         }
 338         reader.request = request;
 339         reader.data = &cond;
 340         reader.next = *prev_reader;
 341         *prev_reader = &reader;
 342
 343         while(!poll_for_reply(c, request, &ret, e))
 344             if(!_xcb_conn_wait(c, &cond, 0, 0))
 345                 break;
 346
 347         for(prev_reader = &c->in.readers;
 348             *prev_reader &&
 349             XCB_SEQUENCE_COMPARE((*prev_reader)->request, <=, request);
 350             prev_reader = &(*prev_reader)->next)
 351         {
 352             if(*prev_reader == &reader)
 353             {
 354                 *prev_reader = (*prev_reader)->next;
 355                 break;
 356             }
 357         }
 358         pthread_cond_destroy(&cond);
 359     }
 360
 361     wake_up_next_reader(c);
 362     _xcb_unlock_io(c);
 363     return ret;
 364 }
 365
 366 int xcb_poll_for_reply(xcb_connection_t *c, unsigned int request, void **reply, xcb_generic_error_t **error)
 367 {
 368     int ret;
 369     if(c->has_error)
 370     {
 371         *reply = 0;
 372         if(error)
 373             *error = 0;
 374         return 1; /* would not block */
 375     }
 376     assert(reply != 0);
 377     _xcb_lock_io(c);
 378     ret = poll_for_reply(c, request, reply, error);
 379     _xcb_unlock_io(c);
 380     return ret;
 381 }
 382
 383 xcb_generic_event_t *xcb_wait_for_event(xcb_connection_t *c)
 384 {
 385     xcb_generic_event_t *ret;
 386     if(c->has_error)
 387         return 0;
 388     _xcb_lock_io(c);
 389     /* get_event returns 0 on empty list. */
 390     while(!(ret = get_event(c)))
 391         if(!_xcb_conn_wait(c, &c->in.event_cond, 0, 0))
 392             break;
 393
 394     wake_up_next_reader(c);
 395     _xcb_unlock_io(c);
 396     return ret;
 397 }
 398
 399 xcb_generic_event_t *xcb_poll_for_event(xcb_connection_t *c)
 400 {
 401     xcb_generic_event_t *ret = 0;
 402     if(!c->has_error)
 403     {
 404         _xcb_lock_io(c);
 405         /* FIXME: follow X meets Z architecture changes. */
 406         ret = get_event(c);
 407         if(!ret && _xcb_in_read(c)) /* _xcb_in_read shuts down the connection on error */
 408             ret = get_event(c);
 409         _xcb_unlock_io(c);
 410     }
 411     return ret;
 412 }
 413
 414 xcb_generic_error_t *xcb_request_check(xcb_connection_t *c, xcb_void_cookie_t cookie)
 415 {
 416     /* FIXME: this could hold the lock to avoid syncing unnecessarily, but
 417      * that would require factoring the locking out of xcb_get_input_focus,
 418      * xcb_get_input_focus_reply, and xcb_wait_for_reply. */
 419     xcb_generic_error_t *ret;
 420     void *reply;
 421     if(c->has_error)
 422         return 0;
 423     if(XCB_SEQUENCE_COMPARE(cookie.sequence,>,c->in.request_expected)
 424        && XCB_SEQUENCE_COMPARE(cookie.sequence,>,c->in.request_completed))
 425     {
 426         free(xcb_get_input_focus_reply(c, xcb_get_input_focus(c), &ret));
 427         assert(!ret);
 428     }
 429     reply = xcb_wait_for_reply(c, cookie.sequence, &ret);
 430     assert(!reply);
 431     return ret;
 432 }
 433
 434 /* Private interface */
 435
 436 int _xcb_in_init(_xcb_in *in)
 437 {
 438     if(pthread_cond_init(&in->event_cond, 0))
 439         return 0;
 440     in->reading = 0;
 441
 442     in->queue_len = 0;
 443
 444     in->request_read = 0;
 445     in->request_completed = 0;
 446
 447     in->replies = _xcb_map_new();
 448     if(!in->replies)
 449         return 0;
 450
 451     in->current_reply_tail = &in->current_reply;
 452     in->events_tail = &in->events;
 453     in->pending_replies_tail = &in->pending_replies;
 454
 455     return 1;
 456 }
 457
 458 void _xcb_in_destroy(_xcb_in *in)
 459 {
 460     pthread_cond_destroy(&in->event_cond);
 461     free_reply_list(in->current_reply);
 462     _xcb_map_delete(in->replies, (void (*)(void *)) free_reply_list);
 463     while(in->events)
 464     {
 465         struct event_list *e = in->events;
 466         in->events = e->next;
 467         free(e->event);
 468         free(e);
 469     }
 470     while(in->pending_replies)
 471     {
 472         pending_reply *pend = in->pending_replies;
 473         in->pending_replies = pend->next;
 474         free(pend);
 475     }
 476 }
 477
 478 int _xcb_in_expect_reply(xcb_connection_t *c, unsigned int request, enum workarounds workaround, int flags)
 479 {
 480     pending_reply *pend = malloc(sizeof(pending_reply));
 481     assert(workaround != WORKAROUND_NONE || flags != 0);
 482     if(!pend)
 483     {
 484         _xcb_conn_shutdown(c);
 485         return 0;
 486     }
 487     pend->request = request;
 488     pend->workaround = workaround;
 489     pend->flags = flags;
 490     pend->next = 0;
 491     *c->in.pending_replies_tail = pend;
 492     c->in.pending_replies_tail = &pend->next;
 493     return 1;
 494 }
 495
 496 int _xcb_in_read(xcb_connection_t *c)
 497 {
 498     int n = read(c->fd, c->in.queue + c->in.queue_len, sizeof(c->in.queue) - c->in.queue_len);
 499     if(n > 0)
 500         c->in.queue_len += n;
 501     while(read_packet(c))
 502         /* empty */;
 503     if((n > 0) || (n < 0 && errno == EAGAIN))
 504         return 1;
 505     _xcb_conn_shutdown(c);
 506     return 0;
 507 }
 508
 509 int _xcb_in_read_block(xcb_connection_t *c, void *buf, int len)
 510 {
 511     int done = c->in.queue_len;
 512     if(len < done)
 513         done = len;
 514
 515     memcpy(buf, c->in.queue, done);
 516     c->in.queue_len -= done;
 517     memmove(c->in.queue, c->in.queue + done, c->in.queue_len);
 518
 519     if(len > done)
 520     {
 521         int ret = read_block(c->fd, (char *) buf + done, len - done);
 522         if(ret <= 0)
 523         {
 524             _xcb_conn_shutdown(c);
 525             return ret;
 526         }
 527     }
 528
 529     return len;
 530 }