summaryrefslogtreecommitdiff
path: root/sys/modules/examples/executor
diff options
context:
space:
mode:
authorkamil <kamil@NetBSD.org>2018-04-13 20:30:09 +0000
committerkamil <kamil@NetBSD.org>2018-04-13 20:30:09 +0000
commit0a2c4d1984310fa496751c9483c5ee7e6b3d433c (patch)
treea503a95960d703663d704f44247c4c49a61af3b0 /sys/modules/examples/executor
parent2a61565763906282c90781cfeb8c7915b2f8da60 (diff)
Add a new example kernel module
executor - basic implementation of callout and RUN_ONCE While there, perform a small cleanup in README. Patch by <Siddharth Muralee> Polishing by myself.
Diffstat (limited to 'sys/modules/examples/executor')
-rw-r--r--sys/modules/examples/executor/Makefile11
-rw-r--r--sys/modules/examples/executor/executor.c108
2 files changed, 119 insertions, 0 deletions
diff --git a/sys/modules/examples/executor/Makefile b/sys/modules/examples/executor/Makefile
new file mode 100644
index 00000000000..50950fc016c
--- /dev/null
+++ b/sys/modules/examples/executor/Makefile
@@ -0,0 +1,11 @@
+# $NetBSD: Makefile,v 1.1 2018/04/13 20:30:09 kamil Exp $
+
+.include "../Makefile.inc"
+
+#S?= /usr/src/sys
+
+KMOD= executor
+SRCS= executor.c
+
+.include <bsd.kmodule.mk>
+
diff --git a/sys/modules/examples/executor/executor.c b/sys/modules/examples/executor/executor.c
new file mode 100644
index 00000000000..395bacaf321
--- /dev/null
+++ b/sys/modules/examples/executor/executor.c
@@ -0,0 +1,108 @@
+/* $NetBSD: executor.c,v 1.1 2018/04/13 20:30:09 kamil Exp $ */
+
+/*-
+ * Copyright (c) 2018 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__KERNEL_RCSID(0, "$NetBSD: executor.c,v 1.1 2018/04/13 20:30:09 kamil Exp $");
+
+#include <sys/param.h>
+#include <sys/module.h>
+#include <sys/callout.h>
+#include <sys/once.h>
+
+/*
+ * Check if dmesg prints
+ * "executor <no-of-seconds-after-loading>" every second
+ * and "executor once" exactly once in the beginning
+ * to test this module
+ */
+
+MODULE(MODULE_CLASS_MISC, executor, NULL);
+
+static void callout_example(void *);
+static int runonce_example(void);
+
+static int executor_count = 0; //To hold the count of seconds
+
+static callout_t sc;
+
+/* Creating a variable that marks whether the function has executed or not */
+static once_t ctl;
+static ONCE_DECL(ctl);
+
+/*
+ * runonce_example : This function should execute only once
+ * It should return 0 as RUN_ONCE calls the function until it returns 0.
+ */
+
+static int
+runonce_example(void) {
+ printf("executor once\n");
+ return 0;
+}
+
+/*
+ * callout_example : This function should get executed every second.
+ * It calls runonce_example each time.
+ * It prints the seconds elasped after the module was loaded.
+ * It reschedules the callout to the next second using callout_schedule
+ */
+
+static void
+callout_example(void *arg) {
+ RUN_ONCE(&ctl, runonce_example);
+ executor_count++;
+ printf("Callout %d\n", executor_count);
+ callout_schedule(&sc, mstohz(1000));
+}
+
+/*
+ * executor_modcmd : has two tasks
+ * On loading the module it needs to initialize a callout handle and schedule
+ * the first callout.
+ * On unloading the module it needs to stop and destroy the callout handle
+ */
+
+static int
+executor_modcmd(modcmd_t cmd, void *arg)
+{
+ switch(cmd) {
+ case MODULE_CMD_INIT:
+ printf("executor module inserted\n");
+ callout_init(&sc, 0);
+ callout_reset(&sc, mstohz(1000), callout_example, NULL);
+ break;
+ case MODULE_CMD_FINI:
+ printf("executor module unloaded\n");
+ callout_stop(&sc);
+ callout_destroy(&sc);
+ break;
+ default:
+ return ENOTTY;
+ }
+ return 0;
+}