From 0a2c4d1984310fa496751c9483c5ee7e6b3d433c Mon Sep 17 00:00:00 2001 From: kamil Date: Fri, 13 Apr 2018 20:30:09 +0000 Subject: Add a new example kernel module executor - basic implementation of callout and RUN_ONCE While there, perform a small cleanup in README. Patch by Polishing by myself. --- sys/modules/examples/executor/executor.c | 108 +++++++++++++++++++++++++++++++ 1 file changed, 108 insertions(+) create mode 100644 sys/modules/examples/executor/executor.c (limited to 'sys/modules/examples/executor/executor.c') 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 +__KERNEL_RCSID(0, "$NetBSD: executor.c,v 1.1 2018/04/13 20:30:09 kamil Exp $"); + +#include +#include +#include +#include + +/* + * Check if dmesg prints + * "executor " 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; +} -- cgit