1 files changed, 81 insertions, 0 deletions
diff --git a/bin/tests/system/dyndb/driver/lock.c b/bin/tests/system/dyndb/driver/lock.c
new file mode 100644
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+++ b/bin/tests/system/dyndb/driver/lock.c
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+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0 AND ISC
+ *
+ * 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.
+ */
+
+/*
+ * Copyright (C) Red Hat
+ *
+ * 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 AUTHORS 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.
+ */
+
+#include "lock.h"
+
+#include <isc/task.h>
+#include <isc/util.h>
+
+/*
+ * Lock BIND dispatcher and allow only single task to run.
+ *
+ * @warning
+ * All calls to isc_task_beginexclusive() have to operate on the same task
+ * otherwise it would not be possible to distinguish recursive locking
+ * from real conflict on the dispatcher lock.
+ * For this reason this wrapper function always works with inst->task.
+ * As a result, this function have to be be called only from inst->task.
+ *
+ * Recursive locking is allowed. Auxiliary variable pointed to by "statep"
+ * stores information if last run_exclusive_enter() operation really locked
+ * something or if the lock was called recursively and was no-op.
+ *
+ * The pair (inst, state) used for run_exclusive_enter() has to be
+ * used for run_exclusive_exit().
+ *
+ * @param[in]  	  inst   The instance with the only task which is allowed to
+ * run.
+ * @param[in,out] statep Lock state: ISC_R_SUCCESS or ISC_R_LOCKBUSY
+ */
+void
+run_exclusive_enter(sample_instance_t *inst, isc_result_t *statep) {
+	REQUIRE(statep != NULL);
+	REQUIRE(*statep == ISC_R_IGNORE);
+
+	*statep = isc_task_beginexclusive(inst->task);
+	RUNTIME_CHECK(*statep == ISC_R_SUCCESS || *statep == ISC_R_LOCKBUSY);
+}
+
+/*
+ * Exit task-exclusive mode.
+ *
+ * @param[in] inst  The instance used for previous run_exclusive_enter() call.
+ * @param[in] state Lock state as returned by run_exclusive_enter().
+ */
+void
+run_exclusive_exit(sample_instance_t *inst, isc_result_t state) {
+	if (state == ISC_R_SUCCESS) {
+		isc_task_endexclusive(inst->task);
+	} else {
+		/* Unlocking recursive lock or the lock was never locked. */
+		INSIST(state == ISC_R_LOCKBUSY || state == ISC_R_IGNORE);
+	}
+
+	return;
+}