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