NAME
reboot —
reboot system or halt
processor
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
#include <sys/reboot.h>
int
reboot(
int
howto,
char
*bootstr);
DESCRIPTION
reboot() reboots the system. Only the super-user may reboot a
machine on demand. However, a reboot is invoked automatically in the event of
unrecoverable system failures.
howto is a mask of options; the system call interface
allows the following options, defined in the include file
<sys/reboot.h>, to be passed to the
new kernel or the new bootstrap and init programs. In addition to the options
described below, other options described in
boothowto(9) may be set, but
such options may be ignored by the system.
Options can be combined together by OR'ing them, eg.
RB_DUMP
|
RB_NOSYNC
would be
interpreted as “dump kernel memory before rebooting and don't sync the
disks”.
RB_AUTOBOOT |
0x0000 |
The default, causing the system to reboot in its usual
fashion. |
RB_ASKNAME |
0x0001 |
Interpreted by the bootstrap program itself, causing
it to prompt on the console as to what file should be booted. Normally,
the system is booted from the file
“xx(0,0)netbsd”,
where xx is the default disk name, without prompting for
the file name. |
RB_DUMP |
0x0100 |
Dump kernel memory before rebooting; see
savecore(8) for more
information. |
RB_HALT |
0x0008 |
the processor is simply halted; no reboot takes place.
This option should be used with caution. |
RB_POWERDOWN |
0x0808 |
This option is always used in conjunction with
RB_HALT , and if the system hardware supports the
function, the system will be powered off, otherwise it has no effect. |
RB_INITNAME |
0x0010 |
An option allowing the specification of an init
program (see init(8)) other
than /sbin/init to be run when the system reboots. This
switch is not currently available. |
RB_KDB |
0x0040 |
Load the symbol table and enable a built-in debugger
in the system. This option will have no useful function if the kernel is
not configured for debugging. Several other options have different meaning
if combined with this option, although their use may not be possible via
the reboot() call. See
ddb(4) for more
information. |
RB_NOSYNC |
0x0004 |
Normally, the disks are sync'd (see
sync(8)) before the processor
is halted or rebooted. This option may be useful if file system changes
have been made manually or if the processor is on fire. |
RB_RDONLY |
0x0080 |
Initially mount the root file system read-only. This
is currently the default, and this option has been deprecated. |
RB_SINGLE |
0x0002 |
Normally, the reboot procedure involves an automatic
disk consistency check and then multi-user operations.
RB_SINGLE prevents this, booting the system with a
single-user shell on the console. RB_SINGLE is
actually interpreted by the
init(8) program in the newly
booted system.
When no options are given (i.e., RB_AUTOBOOT is
used), the system is rebooted from file ``netbsd'' 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 normally performed (see
fsck(8)). |
RB_STRING |
0x0400 |
bootstr is a string passed to
the firmware on the machine, if possible, if this option is set. Currently
this is only implemented on the sparc and the sun3 ports. |
RB_USERCONF |
0x1000 |
Initially invoke the
userconf(4) facility when
the system starts up again, if it has been compiled into the kernel that
is loaded. |
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.
SEE ALSO
ddb(4),
crash(8),
halt(8),
init(8),
reboot(8),
savecore(8),
boothowto(9)
HISTORY
The
reboot() function call appeared in
4.0BSD.
The
RB_DFLTROOT
option is now
obsolete.