1 files changed, 255 insertions, 0 deletions
diff --git a/lib/isc/win32/condition.c b/lib/isc/win32/condition.c
new file mode 100644
index 0000000..ca11bce
--- /dev/null
+++ b/lib/isc/win32/condition.c
@@ -0,0 +1,255 @@
+/*
+ * 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));
+}