reboot(2)
NAME
reboot − reboot system or halt processor
SYNTAX
#include <sys/reboot.h>
reboot(howto)
int howto;
DESCRIPTION
The reboot system call reboots the system, and is invoked automatically in the event of unrecoverable system failures. The howto is a mask of options passed to the bootstrap program. The system call interface permits only RB_HALT or RB_AUTOBOOT to be passed to the reboot program; the other flags are used in scripts stored on the console storage media, or used in manual bootstrap procedures. When none of these options (for example, RB_AUTOBOOT) is given, the system is rebooted from file “vmunix” 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_HALT
the processor is simply halted; no reboot takes place. RB_HALT should be used with caution.
RB_ASKNAME
Interpreted by the bootstrap program itself, causing it to inquire as to what file should be booted. Normally, the system is booted from the file “xx(0,0)vmunix” without asking.
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(8) program in the newly booted system. This switch is not available from the system call interface.
Only the superuser may reboot a machine.
RETURN VALUE
If successful, this call never returns. Otherwise, a −1 is returned and an error is returned in the global variable errno.
DIAGNOSTICS
[EPERM] The caller is not the superuser.