/* * Copyright (C) 2004, 2006, 2007 Internet Systems Consortium, Inc. ("ISC") * Copyright (C) 1998-2001 Internet Software Consortium. * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR * PERFORMANCE OF THIS SOFTWARE. */ /* $Id: condition.c,v 1.23 2007-06-18 23:47:49 tbox Exp $ */ #include #include #include #include #include #include #define LSIGNAL 0 #define LBROADCAST 1 isc_result_t isc_condition_init(isc_condition_t *cond) { HANDLE h; REQUIRE(cond != NULL); cond->waiters = 0; /* * This handle is shared across all threads */ h = CreateEvent(NULL, FALSE, FALSE, NULL); if (h == NULL) { /* XXX */ return (ISC_R_UNEXPECTED); } cond->events[LSIGNAL] = h; /* * The threadlist will hold the actual events needed * for the wait condition */ ISC_LIST_INIT(cond->threadlist); return (ISC_R_SUCCESS); } /* * Add the thread to the threadlist along with the required events */ static isc_result_t register_thread(unsigned long thrd, isc_condition_t *gblcond, isc_condition_thread_t **localcond) { HANDLE hc; isc_condition_thread_t *newthread; REQUIRE(localcond != NULL && *localcond == NULL); newthread = malloc(sizeof(isc_condition_thread_t)); if (newthread == NULL) return (ISC_R_NOMEMORY); /* * Create the thread-specific handle */ hc = CreateEvent(NULL, FALSE, FALSE, NULL); if (hc == NULL) { free(newthread); return (ISC_R_UNEXPECTED); } /* * Add the thread ID and handles to list of threads for broadcast */ newthread->handle[LSIGNAL] = gblcond->events[LSIGNAL]; newthread->handle[LBROADCAST] = hc; newthread->th = thrd; /* * The thread is holding the manager lock so this is safe */ ISC_LIST_APPEND(gblcond->threadlist, newthread, link); *localcond = newthread; return (ISC_R_SUCCESS); } static isc_result_t find_thread_condition(unsigned long thrd, isc_condition_t *cond, isc_condition_thread_t **threadcondp) { isc_condition_thread_t *threadcond; REQUIRE(threadcondp != NULL && *threadcondp == NULL); /* * Look for the thread ID. */ for (threadcond = ISC_LIST_HEAD(cond->threadlist); threadcond != NULL; threadcond = ISC_LIST_NEXT(threadcond, link)) { if (threadcond->th == thrd) { *threadcondp = threadcond; return (ISC_R_SUCCESS); } } /* * Not found, so add it. */ return (register_thread(thrd, cond, threadcondp)); } isc_result_t isc_condition_signal(isc_condition_t *cond) { /* * Unlike pthreads, the caller MUST hold the lock associated with * the condition variable when calling us. */ REQUIRE(cond != NULL); if (!SetEvent(cond->events[LSIGNAL])) { /* XXX */ return (ISC_R_UNEXPECTED); } return (ISC_R_SUCCESS); } isc_result_t isc_condition_broadcast(isc_condition_t *cond) { isc_condition_thread_t *threadcond; isc_boolean_t failed = ISC_FALSE; /* * Unlike pthreads, the caller MUST hold the lock associated with * the condition variable when calling us. */ REQUIRE(cond != NULL); /* * Notify every thread registered for this */ for (threadcond = ISC_LIST_HEAD(cond->threadlist); threadcond != NULL; threadcond = ISC_LIST_NEXT(threadcond, link)) { if (!SetEvent(threadcond->handle[LBROADCAST])) failed = ISC_TRUE; } if (failed) return (ISC_R_UNEXPECTED); return (ISC_R_SUCCESS); } isc_result_t isc_condition_destroy(isc_condition_t *cond) { isc_condition_thread_t *next, *threadcond; REQUIRE(cond != NULL); REQUIRE(cond->waiters == 0); (void)CloseHandle(cond->events[LSIGNAL]); /* * Delete the threadlist */ threadcond = ISC_LIST_HEAD(cond->threadlist); while (threadcond != NULL) { next = ISC_LIST_NEXT(threadcond, link); DEQUEUE(cond->threadlist, threadcond, link); (void) CloseHandle(threadcond->handle[LBROADCAST]); free(threadcond); threadcond = next; } return (ISC_R_SUCCESS); } /* * This is always called when the mutex (lock) is held, but because * we are waiting we need to release it and reacquire it as soon as the wait * is over. This allows other threads to make use of the object guarded * by the mutex but it should never try to delete it as long as the * number of waiters > 0. Always reacquire the mutex regardless of the * result of the wait. Note that EnterCriticalSection will wait to acquire * the mutex. */ static isc_result_t wait(isc_condition_t *cond, isc_mutex_t *mutex, DWORD milliseconds) { DWORD result; isc_result_t tresult; isc_condition_thread_t *threadcond = NULL; /* * Get the thread events needed for the wait */ tresult = find_thread_condition(isc_thread_self(), cond, &threadcond); if (tresult != ISC_R_SUCCESS) return (tresult); cond->waiters++; LeaveCriticalSection(mutex); result = WaitForMultipleObjects(2, threadcond->handle, FALSE, milliseconds); EnterCriticalSection(mutex); cond->waiters--; if (result == WAIT_FAILED) { /* XXX */ return (ISC_R_UNEXPECTED); } if (result == WAIT_TIMEOUT) return (ISC_R_TIMEDOUT); return (ISC_R_SUCCESS); } isc_result_t isc_condition_wait(isc_condition_t *cond, isc_mutex_t *mutex) { return (wait(cond, mutex, INFINITE)); } isc_result_t isc_condition_waituntil(isc_condition_t *cond, isc_mutex_t *mutex, isc_time_t *t) { DWORD milliseconds; isc_uint64_t microseconds; isc_time_t now; if (isc_time_now(&now) != ISC_R_SUCCESS) { /* XXX */ return (ISC_R_UNEXPECTED); } microseconds = isc_time_microdiff(t, &now); if (microseconds > 0xFFFFFFFFi64 * 1000) milliseconds = 0xFFFFFFFF; else milliseconds = (DWORD)(microseconds / 1000); return (wait(cond, mutex, milliseconds)); }