1.\" Copyright (c) 1980, 1991 The Regents of the University of California. 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.\" 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 6.5 (Berkeley) 3/10/91 33.\" 34.Dd March 10, 1991 35.Dt REBOOT 2 36.Os BSD 4 37.Sh NAME 38.Nm reboot 39.Nd reboot system or halt processor 40.Sh SYNOPSIS 41.Fd #include <unistd.h> 42.Fd #include <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.Aq Pa 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)vmunix , 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_INITNAME 85An option allowing the specification of an init program (see 86.Xr init 8 ) 87other than 88.Pa /sbin/init 89to be run when the system reboots. 90This switch is not currently available. 91.It Dv RB_KDB 92Load the symbol table and enable a built-in debugger in the system. 93This option will have no useful function if the kernel is not configured 94for debugging. 95Several other options have different meaning if combined 96with this option, although their use may not be possible 97via the 98.Fn reboot 99call. 100See 101.Xr kadb 4 102for more information. 103.It Dv RB_NOSYNC 104Normally, the disks are sync'd (see 105.Xr sync 8 ) 106before the processor is halted or rebooted. 107This option may be useful if file system changes have been made manually 108or if the processor is on fire. 109.It Dv RB_RDONLY 110Initially mount the root file system read-only. 111This is currently the default, and this option has been deprecated. 112.It Dv RB_SINGLE 113Normally, the reboot procedure involves an automatic disk consistency 114check and then multi-user operations. 115.Dv RB_SINGLE 116prevents this, booting the system with a single-user shell 117on the console. 118.Dv RB_SINGLE 119is actually interpreted by the 120.Xr init 8 121program in the newly booted system. 122.Pp 123When no options are given (i.e., 124.Dv RB_AUTOBOOT 125is used), the system is 126rebooted from file ``vmunix'' in the root file system of unit 0 127of a disk chosen in a processor specific way. 128An automatic consistency check of the disks is normally performed 129(see 130.Xr fsck 8 ) . 131.El 132.Sh RETURN VALUES 133If successful, this call never returns. 134Otherwise, a -1 is returned and an error is returned in the global 135variable 136.Va errno . 137.Sh ERRORS 138.Bl -tag -width Er 139.It Bq Er EPERM 140The caller is not the super-user. 141.El 142.Sh SEE ALSO 143.Xr kadb 4 , 144.Xr crash 8 , 145.Xr halt 8 , 146.Xr init 8 , 147.Xr reboot 8 , 148.Xr savecore 8 149.Sh BUGS 150The HP300 implementation supports neither 151.Dv RB_DFLTROOT 152nor 153.Dv RB_KDB . 154.Sh HISTORY 155The 156.Nm 157function call appeared in 158.Bx 4.0 . 159