1.\" $OpenBSD: reboot.2,v 1.2 1996/10/08 01:20:13 michaels Exp $ 2.\" $NetBSD: reboot.2,v 1.5 1995/02/27 12:36:02 cgd Exp $ 3.\" 4.\" Copyright (c) 1980, 1991, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" @(#)reboot.2 8.1 (Berkeley) 6/4/93 36.\" 37.Dd June 4, 1993 38.Dt REBOOT 2 39.Os BSD 4 40.Sh NAME 41.Nm reboot 42.Nd reboot system or halt processor 43.Sh SYNOPSIS 44.Fd #include <unistd.h> 45.Fd #include <sys/reboot.h> 46.Ft int 47.Fn reboot "int howto" 48.Sh DESCRIPTION 49.Fn reboot 50reboots the system. Only the super-user may reboot a machine on demand. 51However, a reboot may be invoked automatically in the event of 52unrecoverable system failures. Programs other than 53.Xr reboot 8 54should not call 55.Fn reboot . 56.Xr Shutdown 8 57or a higher-level API will shut the system down cleanly. 58.Pp 59.Fa Howto 60is a mask of options; the system call interface allows the following 61options, defined in the include file 62.Aq Pa sys/reboot.h , 63to be passed 64to the new kernel or the new bootstrap and init programs. 65.Bl -tag -width RB_INITNAMEA 66.It Dv RB_AUTOBOOT 67The default, causing the system to reboot in its usual fashion. 68.It Dv RB_ASKNAME 69Interpreted by the bootstrap program itself, causing it to 70prompt on the console as to what file should be booted. 71Normally, the system is booted from the file 72.Dq Em xx Ns No (0,0)bsd , 73where 74.Em xx 75is the default disk name, 76without prompting for the file name. 77.It Dv RB_DFLTROOT 78Use the compiled in root device. 79Normally, the system uses the device from which it was booted 80as the root device if possible. 81(The default behavior is dependent on the ability of the bootstrap program 82to determine the drive from which it was loaded, which is not possible 83on all systems.) 84.It Dv RB_DUMP 85Dump kernel memory before rebooting; see 86.Xr savecore 8 87for more information. 88.It Dv RB_HALT 89the processor is simply halted; no reboot takes place. 90This option should be used with caution. 91.It Dv RB_INITNAME 92An option allowing the specification of an init program (see 93.Xr launchd 8 ) 94other than 95.Pa /sbin/launchd 96to be run when the system reboots. 97This switch is not currently available. 98.It Dv RB_KDB 99Load the symbol table and enable a built-in debugger in the system. 100This option will have no useful function if the kernel is not configured 101for debugging. 102Several other options have different meaning if combined 103with this option, although their use may not be possible 104via the 105.Fn reboot 106call. 107See 108.Xr kadb 4 109for more information. 110.It Dv RB_NOSYNC 111Normally, the disks are sync'd (see 112.Xr sync 8 ) 113before the processor is halted or rebooted. 114This option may be useful if file system changes have been made manually 115or if the processor is on fire. 116.It Dv RB_RDONLY 117Initially mount the root file system read-only. 118This is currently the default, and this option has been deprecated. 119.It Dv RB_SINGLE 120Normally, the reboot procedure involves an automatic disk consistency 121check and then multi-user operations. 122.Dv RB_SINGLE 123prevents this, booting the system with a single-user shell 124on the console. 125.Dv RB_SINGLE 126is actually interpreted by the 127.Xr launchd 8 128program in the newly booted system. 129.Pp 130When no options are given (i.e., 131.Dv RB_AUTOBOOT 132is used), the system is 133rebooted from file ``bsd'' in 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.El 139.Sh RETURN VALUES 140If successful, this call never returns. 141Otherwise, a -1 is returned and an error is returned in the global 142variable 143.Va errno . 144.Sh ERRORS 145.Bl -tag -width Er 146.It Bq Er EPERM 147The caller is not the super-user. 148.El 149.Sh SEE ALSO 150.Xr shutdown 8 , 151.Xr halt 8 , 152.Xr launchd 8 , 153.Xr reboot 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