reboot(2) — 4 BSD

NAME

reboot − reboot system or halt processor

SYNOPSIS

#include <sys/reboot.h>
int reboot (howto)
int howto;

DESCRIPTION

reboot reboots the system, and is invoked automatically in the event of unrecoverable system failures. Howto is a mask of options passed to the bootstrap program. The valid bits are described below. When none of these options (e.g. RB_AUTOBOOT) is given, the system is rebooted from file unix in the root file system of unit 0 of a disk chosen in a processor specific way. An automatic consistency check of the disks is then normally performed.

The bits of howto are:

RB_DUMP
Force a system core dump prior to rebooting.

RB_HALT
The processor is simply halted; no reboot takes place.

RB_NOSYNC
Do not sync the disk prior to rebooting. This option should only be used in an extreme situation.

RB_SINGLE
Normally, the reboot procedure involves an automatic disk consistency check and then multi-user operations. RB_SINGLE prevents the consistency check, rather simply booting the system with a single-user shell on the console. RB_SINGLE is interpreted by the init(1M) program in the newly booted system.

RB_WRITABLE
Normally, a disk consistency check is performed on a read-only instantiation of the root file system; following the disk consistency check, the root file system in mounted a writable. If the root file system needs to be manually checked, the above steps can be circumvented by specifying RW_WRITABLE. RB_SINGLE should always be specified along with RB_WRITABLE.

Only the super-user or a user who has an effective access vector of ACC_REBOOT may reboot a machine.

RETURN VALUES

If successful, this call never returns. Otherwise, a −1 is returned and an error is returned in the global variable errno.

ERRORS

[EPERM] The caller is not the super-user.

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