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-rw-r--r--lib/isc/win32/condition.c255
1 files changed, 255 insertions, 0 deletions
diff --git a/lib/isc/win32/condition.c b/lib/isc/win32/condition.c
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+++ b/lib/isc/win32/condition.c
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+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, you can obtain one at https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+#include <inttypes.h>
+#include <stdbool.h>
+
+#include <isc/assertions.h>
+#include <isc/condition.h>
+#include <isc/error.h>
+#include <isc/strerr.h>
+#include <isc/thread.h>
+#include <isc/time.h>
+#include <isc/util.h>
+
+#define LSIGNAL 0
+#define LBROADCAST 1
+
+void
+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) {
+ char strbuf[ISC_STRERRORSIZE];
+ DWORD err = GetLastError();
+ strerror_r(err, strbuf, sizeof(strbuf));
+ isc_error_fatal(__FILE__, __LINE__, "CreateEvent failed: %s",
+ strbuf);
+ }
+ cond->events[LSIGNAL] = h;
+
+ /*
+ * The threadlist will hold the actual events needed
+ * for the wait condition
+ */
+ ISC_LIST_INIT(cond->threadlist);
+}
+
+/*
+ * 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_LINK_INIT(newthread, link);
+ ISC_LIST_APPEND(gblcond->threadlist, newthread, link);
+ *localcond = newthread;
+ return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+find_thread_condition(uintptr_t 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;
+ bool failed = 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 = 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;
+ 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));
+}