1.\" Copyright (c) 1980, 1991, 1993 2.\" The Regents of the University of California. 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.\" 3. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)reboot.2 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD: src/lib/libc/sys/reboot.2,v 1.9.2.4 2001/12/14 18:34:01 ru Exp $ 30.\" $DragonFly: src/lib/libc/sys/reboot.2,v 1.4 2006/05/26 19:39:37 swildner Exp $ 31.\" 32.Dd June 4, 1993 33.Dt REBOOT 2 34.Os 35.Sh NAME 36.Nm reboot 37.Nd reboot system or halt processor 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In unistd.h 42.In sys/reboot.h 43.Ft int 44.Fn reboot "int howto" 45.Sh DESCRIPTION 46.Fn Reboot 47reboots the system. 48Only the super-user may reboot a machine on demand. 49However, a reboot is invoked 50automatically in the event of unrecoverable system failures. 51.Pp 52.Fa Howto 53is a mask of options; the system call interface allows the following 54options, defined in the include file 55.In sys/reboot.h , 56to be passed 57to the new kernel or the new bootstrap and init programs. 58.Bl -tag -width RB_INITNAMEA 59.It Dv RB_AUTOBOOT 60The default, causing the system to reboot in its usual fashion. 61.It Dv RB_ASKNAME 62Interpreted by the bootstrap program itself, causing it to 63prompt on the console as to what file should be booted. 64Normally, the system is booted from the file 65.Dq Em xx Ns No (0,0)kernel , 66where 67.Em xx 68is the default disk name, 69without prompting for the file name. 70.It Dv RB_DFLTROOT 71Use the compiled in root device. 72Normally, the system uses the device from which it was booted 73as the root device if possible. 74(The default behavior is dependent on the ability of the bootstrap program 75to determine the drive from which it was loaded, which is not possible 76on all systems.) 77.It Dv RB_DUMP 78Dump kernel memory before rebooting; see 79.Xr savecore 8 80for more information. 81.It Dv RB_HALT 82the processor is simply halted; no reboot takes place. 83This option should be used with caution. 84.It Dv RB_POWEROFF 85After halting, the shutdown code will do what it can to turn 86off the power. 87This requires hardware support. 88.It Dv RB_INITNAME 89An option allowing the specification of an init program (see 90.Xr init 8 ) 91other than 92.Pa /sbin/init 93to be run when the system reboots. 94This switch is not currently available. 95.It Dv RB_KDB 96Load the symbol table and enable a built-in debugger in the system. 97This option will have no useful function if the kernel is not configured 98for debugging. 99Several other options have different meaning if combined 100with this option, although their use may not be possible 101via the 102.Fn reboot 103call. 104See 105.Xr ddb 4 106for more information. 107.It Dv RB_NOSYNC 108Normally, the disks are sync'd (see 109.Xr sync 8 ) 110before the processor is halted or rebooted. 111This option may be useful if file system changes have been made manually 112or if the processor is on fire. 113.It Dv RB_RDONLY 114Initially mount the root file system read-only. 115This is currently the default, and this option has been deprecated. 116.It Dv RB_SINGLE 117Normally, the reboot procedure involves an automatic disk consistency 118check and then multi-user operations. 119.Dv RB_SINGLE 120prevents this, booting the system with a single-user shell 121on the console. 122.Dv RB_SINGLE 123is actually interpreted by the 124.Xr init 8 125program in the newly booted system. 126.El 127.Pp 128When no options are given (i.e., 129.Dv RB_AUTOBOOT 130is used), the system is 131rebooted from file 132.Dq kernel 133in the root file system of unit 0 134of a disk chosen in a processor specific way. 135An automatic consistency check of the disks is normally performed 136(see 137.Xr fsck 8 ) . 138.Sh RETURN VALUES 139If successful, this call never returns. 140Otherwise, a -1 is returned and an error is returned in the global 141variable 142.Va errno . 143.Sh ERRORS 144.Bl -tag -width Er 145.It Bq Er EPERM 146The caller is not the super-user. 147.El 148.Sh SEE ALSO 149.Xr crash 8 , 150.Xr halt 8 , 151.Xr init 8 , 152.Xr reboot 8 , 153.Xr savecore 8 154.Sh HISTORY 155The 156.Fn reboot 157function call appeared in 158.Bx 4.0 . 159.Sh BUGS 160The HP300 implementation supports neither 161.Dv RB_DFLTROOT 162nor 163.Dv RB_KDB . 164