1 files changed, 157 insertions, 0 deletions
diff --git a/lib/isc/taskpool.c b/lib/isc/taskpool.c
new file mode 100644
index 0000000..3099532
--- /dev/null
+++ b/lib/isc/taskpool.c
@@ -0,0 +1,157 @@
+/*
+ * 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.
+ */
+
+/*! \file */
+
+#include <stdbool.h>
+
+#include <isc/mem.h>
+#include <isc/random.h>
+#include <isc/taskpool.h>
+#include <isc/util.h>
+
+/***
+ *** Types.
+ ***/
+
+struct isc_taskpool {
+	isc_mem_t *mctx;
+	isc_taskmgr_t *tmgr;
+	unsigned int ntasks;
+	unsigned int quantum;
+	isc_task_t **tasks;
+};
+
+/***
+ *** Functions.
+ ***/
+
+static void
+alloc_pool(isc_taskmgr_t *tmgr, isc_mem_t *mctx, unsigned int ntasks,
+	   unsigned int quantum, isc_taskpool_t **poolp) {
+	isc_taskpool_t *pool;
+	unsigned int i;
+
+	pool = isc_mem_get(mctx, sizeof(*pool));
+
+	pool->mctx = NULL;
+	isc_mem_attach(mctx, &pool->mctx);
+	pool->ntasks = ntasks;
+	pool->quantum = quantum;
+	pool->tmgr = tmgr;
+	pool->tasks = isc_mem_get(mctx, ntasks * sizeof(isc_task_t *));
+	for (i = 0; i < ntasks; i++) {
+		pool->tasks[i] = NULL;
+	}
+
+	*poolp = pool;
+}
+
+isc_result_t
+isc_taskpool_create(isc_taskmgr_t *tmgr, isc_mem_t *mctx, unsigned int ntasks,
+		    unsigned int quantum, bool priv, isc_taskpool_t **poolp) {
+	unsigned int i;
+	isc_taskpool_t *pool = NULL;
+
+	INSIST(ntasks > 0);
+
+	/* Allocate the pool structure */
+	alloc_pool(tmgr, mctx, ntasks, quantum, &pool);
+
+	/* Create the tasks */
+	for (i = 0; i < ntasks; i++) {
+		isc_result_t result = isc_task_create_bound(tmgr, quantum,
+							    &pool->tasks[i], i);
+		if (result != ISC_R_SUCCESS) {
+			isc_taskpool_destroy(&pool);
+			return (result);
+		}
+		isc_task_setprivilege(pool->tasks[i], priv);
+		isc_task_setname(pool->tasks[i], "taskpool", NULL);
+	}
+
+	*poolp = pool;
+	return (ISC_R_SUCCESS);
+}
+
+void
+isc_taskpool_gettask(isc_taskpool_t *pool, isc_task_t **targetp) {
+	isc_task_attach(pool->tasks[isc_random_uniform(pool->ntasks)], targetp);
+}
+
+int
+isc_taskpool_size(isc_taskpool_t *pool) {
+	REQUIRE(pool != NULL);
+	return (pool->ntasks);
+}
+
+isc_result_t
+isc_taskpool_expand(isc_taskpool_t **sourcep, unsigned int size, bool priv,
+		    isc_taskpool_t **targetp) {
+	isc_taskpool_t *pool;
+
+	REQUIRE(sourcep != NULL && *sourcep != NULL);
+	REQUIRE(targetp != NULL && *targetp == NULL);
+
+	pool = *sourcep;
+	*sourcep = NULL;
+	if (size > pool->ntasks) {
+		isc_taskpool_t *newpool = NULL;
+		unsigned int i;
+
+		/* Allocate a new pool structure */
+		alloc_pool(pool->tmgr, pool->mctx, size, pool->quantum,
+			   &newpool);
+
+		/* Copy over the tasks from the old pool */
+		for (i = 0; i < pool->ntasks; i++) {
+			newpool->tasks[i] = pool->tasks[i];
+			pool->tasks[i] = NULL;
+		}
+
+		/* Create new tasks */
+		for (i = pool->ntasks; i < size; i++) {
+			isc_result_t result =
+				isc_task_create_bound(pool->tmgr, pool->quantum,
+						      &newpool->tasks[i], i);
+			if (result != ISC_R_SUCCESS) {
+				*sourcep = pool;
+				isc_taskpool_destroy(&newpool);
+				return (result);
+			}
+			isc_task_setprivilege(newpool->tasks[i], priv);
+			isc_task_setname(newpool->tasks[i], "taskpool", NULL);
+		}
+
+		isc_taskpool_destroy(&pool);
+		pool = newpool;
+	}
+
+	*targetp = pool;
+	return (ISC_R_SUCCESS);
+}
+
+void
+isc_taskpool_destroy(isc_taskpool_t **poolp) {
+	unsigned int i;
+	isc_taskpool_t *pool = *poolp;
+	*poolp = NULL;
+	for (i = 0; i < pool->ntasks; i++) {
+		if (pool->tasks[i] != NULL) {
+			isc_task_detach(&pool->tasks[i]);
+		}
+	}
+	isc_mem_put(pool->mctx, pool->tasks,
+		    pool->ntasks * sizeof(isc_task_t *));
+	isc_mem_putanddetach(&pool->mctx, pool, sizeof(*pool));
+}