1.\" Copyright (c) 2003 Hiten M. Pandya 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.\" $FreeBSD$ 26.\" 27.Dd December 1, 2010 28.Dt SYSINIT 9 29.Os 30.Sh NAME 31.Nm SYSINIT , 32.Nm SYSUNINIT 33.Nd a framework for dynamic kernel initialization 34.Sh SYNOPSIS 35.In sys/param.h 36.In sys/kernel.h 37.Fn SYSINIT "uniquifier" "enum sysinit_sub_id subsystem" "enum sysinit_elem_order order" "sysinit_cfunc_t func" "const void *ident" 38.Fn SYSUNINIT "uniquifier" "enum sysinit_sub_id subsystem" "enum sysinit_elem_order order" "sysinit_cfunc_t func" "const void *ident" 39.Sh DESCRIPTION 40.Nm 41is a mechanism for scheduling the execution of initialization and teardown 42routines. 43This is similar to init and fini routines with the addition of explicit 44ordering metadata. 45It allows runtime ordering of subsystem initialization in the kernel as well 46as kernel modules (KLDs). 47.Pp 48The 49.Fn SYSINIT 50macro creates a 51.Vt struct sysinit 52and stores it in a startup linker set. 53The 54.Vt struct sysinit 55type as well as the subsystem identifier constants 56.Pq Dv SI_SUB_* 57and initialization ordering constants 58.Pq Dv SI_ORDER_* 59are defined in 60.In sys/kernel.h : 61.Bd -literal 62struct sysinit { 63 enum sysinit_sub_id subsystem; /* subsystem identifier*/ 64 enum sysinit_elem_order order; /* init order within subsystem*/ 65 sysinit_cfunc_t func; /* function */ 66 const void *udata; /* multiplexer/argument */ 67}; 68.Ed 69.Pp 70The 71.Fn SYSINIT 72macro takes a 73.Fa uniquifier 74argument to identify the particular function dispatch data, 75the 76.Fa subsystem 77type of startup interface, the subsystem element 78.Fa order 79of initialization within the subsystem, the 80.Fa func 81function to call, 82and the data specified in 83.Fa ident 84argument to pass the function. 85.Pp 86The 87.Fn SYSUNINIT 88macro behaves similarly to the 89.Fn SYSINIT 90macro except that it adds the data to a shutdown linker set. 91.Pp 92The startup linker set for the kernel is scanned during boot to build a 93sorted list of initialization routines. 94The initialization routines are then executed in the sorted order. 95The 96.Fa subsystem 97is used as the primary key and is sorted in ascending order. 98The 99.Fa order 100is used as the secondary key and is sorted in ascending order. 101The relative order of two routines that have the same 102.Fa subsystem 103and 104.Fa order 105is undefined. 106.Pp 107The startup linker sets for modules that are loaded together with the kernel 108by the boot loader are scanned during the 109.Dv SI_SUB_KLD 110subsystem initialization. 111These modules' initialization routines are sorted and merged into the kernel's 112list of startup routines and are executed during boot along with the kernel's 113initialization routines. 114Note that this has the effect that any initialization routines in a kernel 115module that are scheduled earlier than 116.Dv SI_SUB_KLD 117are not executed until after 118.Dv SI_SUB_KLD 119during boot. 120.Pp 121The startup linker set for a kernel module loaded at runtime via 122.Xr kldload 2 123is scanned, sorted, and executed when the module is loaded. 124.Pp 125The shutdown linker set for a kernel module is scanned, sorted, and executed 126when a kernel module is unloaded. 127The teardown routines are sorted in the reverse order of the initialization 128routines. 129The teardown routines of the kernel and any loaded modules are 130.Sy not 131executed during shutdown. 132.Sh EXAMPLES 133This example shows the SYSINIT which displays the copyright notice during boot: 134.Bd -literal -offset indent 135static void 136print_caddr_t(void *data) 137{ 138 printf("%s", (char *)data); 139} 140SYSINIT(announce, SI_SUB_COPYRIGHT, SI_ORDER_FIRST, print_caddr_t, 141 copyright); 142.Ed 143.Sh SEE ALSO 144.Xr kld 4 , 145.Xr DECLARE_MODULE 9 , 146.Xr DEV_MODULE 9 , 147.Xr DRIVER_MODULE 9 , 148.Xr MTX_SYSINIT 9 , 149.Xr SYSCALL_MODULE 9 150.Sh HISTORY 151The 152.Nm 153framework first appeared in 154.Fx 2.2 . 155.Sh AUTHORS 156.An -nosplit 157The 158.Nm 159framework was written by 160.An Terrence Lambert Aq terry@FreeBSD.org . 161.Pp 162This manual page was written by 163.An Hiten Pandya Aq hmp@FreeBSD.org . 164