.\"	$OpenBSD: boot.8,v 1.14 2024/11/05 09:42:48 miod Exp $
.\"
.\" Copyright (c) 1997-2001 Michael Shalayeff
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.Dd $Mdocdate: November 5 2024 $
.Dt BOOT 8 landisk
.Os
.Sh NAME
.Nm boot ,
.Nm boot.conf
.Nd landisk-specific second-stage bootstrap
.Sh DESCRIPTION
The main purpose of this program is to load the system kernel from the
root file system of the machine.
.Pp
This program is loaded by the
.Xr xxboot 8
primary bootstrap loader and provides a convenient way to load the kernel.
This program acts as an enhanced boot monitor for landisk systems, providing
a common interface for the kernel to start from.
.Pp
Basic operations include:
.Pp
.Bl -bullet -compact
.It
Loading kernels from any device supported by your system firmware.
.It
Loading kernels compressed by
.Xr gzip 1 .
.It
Providing an interactive command line.
.El
.Pp
The sequence of its operation is as follows: initialization,
parsing the configuration file, then an interactive command line.
While at the command line you have 5 seconds to type any commands, if needed.
If time expires, the kernel will be loaded according to
the current variable settings (see the
.Ic set
command).
If the kernel load fails, a second attempt is made with the timeout increased
by one second.
The sequence of
.Nm
operations is as follows:
.Bl -enum
.It
If the file
.Pa /etc/boot.conf
exists on the filesystem
.Nm
was loaded from, open and parse it.
Lines beginning with the
.Sq #
character,
as well as whitespace at the beginning of lines,
are ignored.
The file may contain any commands
.Nm
accepts at the interactive prompt.
Though default settings usually suffice, they can be changed here.
.\" XXX CHECK_SKIP_CONF is not defined...
.\" .Pa boot.conf
.\" processing can be skipped by holding down either Control key as
.\" .Nm
.\" starts.
.It
The header line
.Pp
.Dl >> OpenBSD/landisk BOOT [x.xx]
.Pp
is displayed to the active console, where
.Ar x.xx
is the version number of the
.Nm
program, followed by the
.Pp
.Dl boot>
.Pp
prompt, which means you are in interactive mode and may enter commands.
If you do not,
.Nm
will proceed to load the kernel with the current parameters after the
timeout period has expired.
.El
.Pp
By default,
.Nm
attempts to load the kernel executable
.Pa /bsd .
If it fails to find the kernel and no alternative kernel image has
been specified, the system will be unable to boot.
.Sh COMMANDS
The following commands are accepted at the
.Nm
prompt:
.Bl -tag -width shorten
.It Ic boot Oo Oo Ar device : Oc Ns Ar image Oc Op Fl acds
Boots the specified kernel image
with any options given.
If
.Ar device
or
.Ar image
are omitted, values from
.Nm
variables will be used.
.Pp
The only bootable device, at the moment, is the internal IDE device (either a
compactflash media or an ATA disk drive), and is named
.Sq cf .
Therefore, to boot kernel
.Pa /bsd
from
.\" XXX no support for partition different from `a' yet...
.\" slice
.\" .Sq a
.\" on
the internal drive, specify
.Dq boot cf:/bsd .
.Bl -tag -width _a_
.It Fl a
Causes the kernel to ask for the
.Nm root
device to use.
.It Fl c
Causes the kernel to go into
.Xr boot_config 8
before performing
.Xr autoconf 4
procedures.
.It Fl d
Causes the kernel to drop into
.Xr ddb 4
at the earliest convenient point.
.It Fl s
Causes the kernel to boot single-user.
.El
.It Ic echo Op Ar args
Displays
.Ar args
on the console device.
.It Ic help
Prints a list of available commands.
.It Ic hexdump Ar addr size
Show
.Ar size
bytes of memory at address
.Ar addr .
.It Ic ls Op Ar directory
Prints contents of the specified
.Ar directory
in long format including: attributes and file type, owner, group,
size, filename.
.It Ic reboot
Reboots the machine by initiating a warm boot procedure.
.It Ic set Op Ar varname Op Ar value
If invoked without arguments, prints a list of variables and their values.
If only
.Ar varname
is specified, displays contents of that variable.
If
.Ar varname
and
.Ar value
are both specified, sets that variable to the given value.
Variables include:
.Pp
.Bl -tag -compact -width db_console
.It Ic db_console
Boolean (0 or 1) to permit entry into the kernel debugger before the
.Em ddb.console
sysctl gets effective.
.It Ic debug
Debug flag if
.Nm
was compiled with DEBUG defined.
.\" XXX Useless until partitions are supported.
.\" .It Nm device
.\" Boot device name (e.g.,
.\" .Li cf0a ,
.\" .Li cf0d ) .
.It Ic howto
Options to pass to the loaded kernel.
.It Ic image
File name containing the kernel image.
.It Ic timeout
Number of seconds boot will wait for human intervention before
booting the default kernel image.
.It Ic time
Displays system time and date.
.El
.Sh FILES
.Bl -tag -width /usr/mdec/xxboot -compact
.It Pa /boot
system bootstrap
.It Pa /etc/boot.conf
system bootstrap's startup file
.It Pa /bsd
kernel image
.It Pa /bsd.rd
kernel image for installation/recovery
.It Pa /usr/mdec/xxboot
first stage bootstrap
.El
.Sh EXAMPLES
Boot the default kernel:
.Pp
.Dl boot> boot
.Pp
Remove the 5 second pause at boot-time permanently, causing
.Nm
to load the kernel immediately without prompting:
.Pp
.Dl # echo \&"boot\&" > /etc/boot.conf
.Pp
Boot the kernel named
.Pa /bsd.rd
in
.Dq User Kernel Configuration
mode (see
.Xr boot_config 8 ) .
This mechanism allows for the explicit enabling and disabling of devices
during the current boot sequence, as well as the modification
of device parameters.
Once booted, such changes can be made permanent by using
.Xr config 8 Ns 's
.Fl e
option.
.Pp
.Dl boot> boot cf:/bsd.rd -c
.Sh SEE ALSO
.Xr gzip 1 ,
.Xr autoconf 4 ,
.Xr ddb 4 ,
.Xr boot_config 8 ,
.Xr fdisk 8 ,
.Xr reboot 8 ,
.Xr xxboot 8
.Sh HISTORY
This program was written by Michael Shalayeff for
.Ox 4.1 .