15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)/* 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * pthread_timechange_handler_np.c 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Description: 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * This translation unit implements miscellaneous thread functions. 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * -------------------------------------------------------------------------- 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Pthreads-win32 - POSIX Threads Library for Win32 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Copyright(C) 1998 John E. Bossom 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Copyright(C) 1999,2005 Pthreads-win32 contributors 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Contact Email: rpj@callisto.canberra.edu.au 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * The current list of contributors is contained 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * in the file CONTRIBUTORS included with the source 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * code distribution. The list can also be seen at the 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * following World Wide Web location: 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * http://sources.redhat.com/pthreads-win32/contributors.html 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * This library is free software; you can redistribute it and/or 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * modify it under the terms of the GNU Lesser General Public 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * License as published by the Free Software Foundation; either 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * version 2 of the License, or (at your option) any later version. 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * This library is distributed in the hope that it will be useful, 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * but WITHOUT ANY WARRANTY; without even the implied warranty of 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Lesser General Public License for more details. 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * You should have received a copy of the GNU Lesser General Public 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * License along with this library in the file COPYING.LIB; 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * if not, write to the Free Software Foundation, Inc., 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) */ 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "pthread.h" 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "implement.h" 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)/* 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Notes on handling system time adjustments (especially negative ones). 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * --------------------------------------------------------------------- 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * This solution was suggested by Alexander Terekhov, but any errors 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * in the implementation are mine - [Ross Johnson] 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 1) The problem: threads doing a timedwait on a CV may expect to timeout 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * at a specific absolute time according to a system timer. If the 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * system clock is adjusted backwards then those threads sleep longer than 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * expected. Also, pthreads-win32 converts absolute times to intervals in 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * order to make use of the underlying Win32, and so waiting threads may 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * awake before their proper abstimes. 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 2) We aren't able to distinquish between threads on timed or untimed waits, 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * so we wake them all at the time of the adjustment so that they can 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * re-evaluate their conditions and re-compute their timeouts. 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 3) We rely on correctly written applications for this to work. Specifically, 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * they must be able to deal properly with spurious wakeups. That is, 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * they must re-test their condition upon wakeup and wait again if 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * the condition is not satisfied. 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) */ 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)void * 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)pthread_timechange_handler_np (void *arg) 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) /* 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * ------------------------------------------------------ 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * DOCPUBLIC 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Broadcasts all CVs to force re-evaluation and 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * new timeouts if required. 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * PARAMETERS 735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * NONE 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * DESCRIPTION 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * Broadcasts all CVs to force re-evaluation and 785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * new timeouts if required. 795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * This routine may be passed directly to pthread_create() 815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * as a new thread in order to run asynchronously. 825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * RESULTS 855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 0 successfully broadcast all CVs 865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * EAGAIN Not all CVs were broadcast 875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * 885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) * ------------------------------------------------------ 895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) */ 905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles){ 915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) int result = 0; 925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) pthread_cond_t cv; 935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ptw32_mcs_local_node_t node; 945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ptw32_mcs_lock_acquire(&ptw32_cond_list_lock, &node); 965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) cv = ptw32_cond_list_head; 985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) while (cv != NULL && 0 == result) 1005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) { 1015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) result = pthread_cond_broadcast (&cv); 1025821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) cv = cv->next; 1035821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1045821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1055821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ptw32_mcs_lock_release(&node); 1065821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1075821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return (void *) (size_t) (result != 0 ? EAGAIN : 0); 1085821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 109