1.\" -*- nroff -*- 2.\" 3.\" Copyright (c) 2000 Alexander Langer 4.\" 5.\" All rights reserved. 6.\" 7.\" This program is free software. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 19.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 22.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28.\" 29.\" $FreeBSD$ 30.\" 31.Dd March 1, 2001 32.Dt MODULE 9 33.Os 34.Sh NAME 35.Nm module 36.Nd structure describing a kernel module 37.Sh DESCRIPTION 38Each module in the kernel is described by a 39.Vt module_t 40structure. 41The structure contains the name of the device, a unique ID number, 42a pointer to an event handler function and to an argument, 43which is given to the event handler, 44as well as some kernel internal data. 45.Pp 46The 47.Xr DECLARE_MODULE 9 48macro 49registers the module with the system. 50.Pp 51When the module is loaded, the event handler function is called with 52the 53.Fa what 54argument set to 55.Dv MOD_LOAD . 56.Pp 57On unload it is first called with 58.Fa what 59set to MOD_QUIESCE . 60If the unload was not forced, a non-zero return will prevent the 61unload from happening. 62.Pp 63If the unload continues 64.Fa what 65is set to 66.Dv MOD_UNLOAD . 67If the module returns non-zero to this, the unload will not happen. 68.Pp 69The difference between MOD_QUIESCE and MOD_UNLOAD is that the module 70should fail MOD_QUIESCE if it is currently in use, whereas MOD_UNLOAD 71should only fail if it is impossible to unload the module, for instance 72because there are memory references to the module which cannot be revoked. 73.Pp 74When the system is shutting down, 75.Fa what 76contains the value of 77.Dv MOD_SHUTDOWN . 78.Pp 79The module should return EOPNOTSUPP for unrecognized values of 80.Fa what . 81.Sh EXAMPLES 82.Bd -literal 83#include <sys/param.h> 84#include <sys/kernel.h> 85#include <sys/module.h> 86 87static int foo_handler(module_t mod, int /*modeventtype_t*/ what, 88 void *arg); 89 90static moduledata_t mod_data= { 91 "foo", 92 foo_handler, 93 0 94}; 95 96MODULE_VERSION(foo, 1); 97MODULE_DEPEND(foo, bar, 1, 3, 4); 98 99DECLARE_MODULE(foo, mod_data, SI_SUB_EXEC, SI_ORDER_ANY); 100.Ed 101.Sh SEE ALSO 102.Xr DECLARE_MODULE 9 , 103.Xr DEV_MODULE 9 , 104.Xr DRIVER_MODULE 9 , 105.Xr MODULE_DEPEND 9 , 106.Xr MODULE_VERSION 9 , 107.Xr SYSCALL_MODULE 9 108.Pp 109.Pa /usr/share/examples/kld 110.Sh AUTHORS 111This man page was written by 112.An Alexander Langer Aq alex@FreeBSD.org . 113