/* $NetBSD: sysctl.c,v 1.1 2018/04/13 01:20:28 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: sysctl.c,v 1.1 2018/04/13 01:20:28 kamil Exp $"); #include <sys/param.h> #include <sys/module.h> #include <sys/sysctl.h> /* * Check if sysctl -A contains an entry * example_subroot1.sysctl_example=0 * to test this module * */ MODULE(MODULE_CLASS_MISC, sysctl, NULL); static int sysctl_example; static struct sysctllog *example_sysctl_log; static void sysctl_example_setup(struct sysctllog **); /* * sysctl_example_setup : * It first creates a subtree by adding a node to the tree. * This node is named as example_subroot1. * * It then creates a node in subtree for the example variable which * is an integer and is defined in this file itself. * * ROOT * | * ------- * | * examples_subroot1 * | * | * sysctl_example (INT) * */ static void sysctl_example_setup(struct sysctllog **clog) { const struct sysctlnode *rnode; sysctl_createv(clog, 0, NULL, &rnode, CTLFLAG_PERMANENT, CTLTYPE_NODE, "example_subroot1", NULL, NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL); sysctl_createv(clog, 0, &rnode, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "sysctl_example", SYSCTL_DESCR("An example for sysctl_example"), NULL, 0, &sysctl_example, 0, CTL_CREATE, CTL_EOL); } /* * The sysctl_example modcmd has two functions. * 1. Call the sysctl_example_setup function to create a sysctl * handle when the module is loaded in the kernel. * 2. Remove the sysctl entry from the kernel once the module * is unloaded. */ static int sysctl_modcmd(modcmd_t cmd, void *arg) { switch(cmd) { case MODULE_CMD_INIT: printf("sysctl module inserted"); sysctl_example_setup(&example_sysctl_log); break; case MODULE_CMD_FINI: printf("sysctl module unloaded"); sysctl_teardown(&example_sysctl_log); break; default: return ENOTTY; } return 0; }