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. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)reboot.2 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD$ 34.\" 35.Dd June 4, 1993 36.Dt REBOOT 2 37.Os BSD 4 38.Sh NAME 39.Nm reboot 40.Nd reboot system or halt processor 41.Sh SYNOPSIS 42.Fd #include <unistd.h> 43.Fd #include <sys/reboot.h> 44.Ft int 45.Fn reboot "int howto" 46.Sh DESCRIPTION 47.Fn Reboot 48reboots the system. 49Only the super-user may reboot a machine on demand. 50However, a reboot is invoked 51automatically in the event of unrecoverable system failures. 52.Pp 53.Fa Howto 54is a mask of options; the system call interface allows the following 55options, defined in the include file 56.Aq Pa sys/reboot.h , 57to be passed 58to the new kernel or the new bootstrap and init programs. 59.Bl -tag -width RB_INITNAMEA 60.It Dv RB_AUTOBOOT 61The default, causing the system to reboot in its usual fashion. 62.It Dv RB_ASKNAME 63Interpreted by the bootstrap program itself, causing it to 64prompt on the console as to what file should be booted. 65Normally, the system is booted from the file 66.Dq Em xx Ns No (0,0)kernel , 67where 68.Em xx 69is the default disk name, 70without prompting for the file name. 71.It Dv RB_DFLTROOT 72Use the compiled in root device. 73Normally, the system uses the device from which it was booted 74as the root device if possible. 75(The default behavior is dependent on the ability of the bootstrap program 76to determine the drive from which it was loaded, which is not possible 77on all systems.) 78.It Dv RB_DUMP 79Dump kernel memory before rebooting; see 80.Xr savecore 8 81for more information. 82.It Dv RB_HALT 83the processor is simply halted; no reboot takes place. 84This option should be used with caution. 85.It Dv RB_POWEROFF 86After halting, the shutdown code will do what it can to turn 87of the power. This 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 kadb 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 BUGS 155The HP300 implementation supports neither 156.Dv RB_DFLTROOT 157nor 158.Dv RB_KDB . 159.Sh HISTORY 160The 161.Fn reboot 162function call appeared in 163.Bx 4.0 . 164