Add a new gptboot(8) man page. Factor out the redundant information

in gpart(8) and boot(8), adding references to gptboot(8) in both.

Reviewed by:	jhb, ae, pjd, Paul Schenkeveld <bsdcan@psconsult.nl>, david_a_bright@dell.com (portions), gjb
MFC after:	1 week
This commit is contained in:
Warren Block 2013-07-01 22:38:36 +00:00
parent 4310207e25
commit 42c916d7ee
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=252492
4 changed files with 264 additions and 66 deletions

View File

@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd January 25, 2013
.Dd July 1, 2013
.Dt GPART 8
.Os
.Sh NAME
@ -645,14 +645,12 @@ The scheme-specific attributes for GPT:
When set, the
.Nm gptboot
stage 1 boot loader will try to boot the system from this partition.
Multiple partitions might be marked with the
Multiple partitions can be marked with the
.Cm bootme
attribute.
In such scenario the
.Nm gptboot
will try all
.Cm bootme
partitions one by one, until the next boot stage is successfully entered.
See
.Xr gptboot 8
for more details.
.It Cm bootonce
Setting this attribute automatically sets the
.Cm bootme
@ -660,49 +658,14 @@ attribute.
When set, the
.Nm gptboot
stage 1 boot loader will try to boot the system from this partition only once.
Partitions with both
.Cm bootonce
and
.Cm bootme
attributes are tried before partitions with only the
.Cm bootme
attribute.
Before
.Cm bootonce
partition is tried, the
.Nm gptboot
removes the
.Cm bootme
attribute and tries to execute the next boot stage.
If it fails, the
.Cm bootonce
attribute that is now alone is replaced with the
.Cm bootfailed
attribute.
If the execution of the next boot stage succeeds, but the system is not fully
booted, the
.Nm gptboot
will look for
.Cm bootonce
attributes alone (without the
.Cm bootme
attribute) on the next system boot and will replace those with the
.Cm bootfailed
attribute.
If the system is fully booted, the
.Pa /etc/rc.d/gptboot
start-up script will look for partition with the
.Cm bootonce
attribute alone, will remove the attribute and log that the system was
successfully booted from this partition.
There should be at most one
.Cm bootonce
partition when system is successfully booted.
Multiple partitions might be marked with the
Multiple partitions can be marked with the
.Cm bootonce
and
.Cm bootme
attribute pairs.
See
.Xr gptboot 8
for more details.
.It Cm bootfailed
This attribute should not be manually managed.
It is managed by the
@ -710,14 +673,9 @@ It is managed by the
stage 1 boot loader and the
.Pa /etc/rc.d/gptboot
start-up script.
This attribute is used to mark partitions that had the
.Cm bootonce
attribute set, but we failed to boot from them.
Once we successfully boot, the
.Pa /etc/rc.d/gptboot
script will log all the partitions we failed to boot from and will remove the
.Cm bootfailed
attributes.
See
.Xr gptboot 8
for more details.
.El
.Pp
The scheme-specific attributes for MBR:
@ -795,20 +753,17 @@ There are two variants of bootstrap code to write to this partition:
.Pa /boot/gptboot
and
.Pa /boot/gptzfsboot .
.Pp
.Pa /boot/gptboot
is used to boot from UFS.
It searches through
is used to boot from UFS partitions.
.Cm gptboot
searches through
.Cm freebsd-ufs
partitions in the GPT and boots from the first one with the
partitions in the GPT and selects one to boot based on the
.Cm bootonce
attribute set.
If that attribute is not found,
.Pa /boot/gptboot
boots from the first
.Cm freebsd-ufs
partition with the
and
.Cm bootme
attribute set.
attributes.
If neither attribute is found,
.Pa /boot/gptboot
boots from the first
@ -817,6 +772,10 @@ partition.
.Pa /boot/loader
.Pq the third bootstrap stage
is loaded from the first partition that matches these conditions.
See
.Xr gptboot 8
for more information.
.Pp
.Pa /boot/gptzfsboot
is used to boot from ZFS.
It searches through the GPT for
@ -1105,7 +1064,8 @@ and
.Xr dd 1 ,
.Xr geom 4 ,
.Xr boot0cfg 8 ,
.Xr geom 8
.Xr geom 8 ,
.Xr gptboot 8
.Sh HISTORY
The
.Nm

View File

@ -36,7 +36,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd July 4, 2010
.Dd July 1, 2013
.Dt BOOT 8 i386
.Os
.Sh NAME
@ -351,6 +351,7 @@ requirement has not been adhered to.
.Xr bsdlabel 8 ,
.Xr btxld 8 ,
.Xr config 8 ,
.Xr gptboot 8 ,
.Xr halt 8 ,
.Xr loader 8 ,
.Xr nextboot 8 ,

View File

@ -3,6 +3,7 @@
.PATH: ${.CURDIR}/../boot2 ${.CURDIR}/../common ${.CURDIR}/../../common
FILES= gptboot
MAN= gptboot.8
NM?= nm

View File

@ -0,0 +1,236 @@
.\" Copyright (c) 2013 Warren Block
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd July 1, 2013
.Dt GPTBOOT 8
.Os
.Sh NAME
.Nm gptboot
.Nd GPT bootcode for UFS on BIOS-based computers
.Sh DESCRIPTION
.Nm
is used on BIOS-based computers to boot from a UFS partition on a
GPT-partitioned disk.
.Nm
is installed in a
.Cm freebsd-boot
partition with
.Xr gpart 8 .
.Sh IMPLEMENTATION NOTES
The GPT standard allows a variable number of partitions, but
.Nm
only boots from tables with 128 partitions or less.
.Sh PARTITION ATTRIBUTES
.Nm
checks and manages several attributes of GPT UFS partitions.
.Bl -tag -width ".Cm bootfailed"
.It Cm bootme
Attempt to boot from this partition.
If more than one partition has the
.Cm bootme
attribute set,
.Nm
will attempt to boot each one until successful.
.It Cm bootonce
Attempt to boot from this partition only one time.
Setting this attribute with
.Xr gpart 8
automatically also sets the
.Cm bootme
attribute.
Multiple partitions may have the
.Cm bootonce
and
.Cm bootme
attributes set.
.It Cm bootfailed
The
.Cm bootfailed
attribute marks partitions that had the
.Cm bootonce
attribute set, but failed to boot.
This attribute is managed by the system.
See
.Sx "BOOTING"
and
.Sx "POST-BOOT ACTIONS"
below for details.
.El
.Sh USAGE
For normal usage, the user does not have to set or manage any of the
partition attributes.
.Nm
will boot from the first UFS partition found.
.Pp
The
.Cm bootonce
attribute can be used for testing an upgraded operating system on
an already-working computer.
The existing system partition is left untouched, and the new version
of the operating system to be tested is installed on another partition.
The
.Cm bootonce
attribute is set on that new test partition.
The next boot is attempted from the test partition.
Success or failure will be shown in the system log files.
After a successful boot of the test partition, a user script can check
the logs and change the
.Cm bootme
attributes so the test partition becomes the new system partition.
Because the
.Cm bootonce
attribute is cleared after an attempted boot, a failed boot will not
leave the system attempting to boot from a partition that will never
succeed.
Instead, the system will boot from the older, known-working operating
system that has not been modified.
If the
.Cm bootme
attribute is set on any partitions, booting will be attempted from them
first.
If no partitions with
.Cm bootme
attributes are found, booting will be attempted from the first UFS
partition found.
.Sh BOOTING
.Nm
first reads the partition table.
All
.Cm freebsd-ufs
partitions with only the
.Cm bootonce
attribute set, indicating a failed boot, are set to
.Cm bootfailed .
.Nm
then scans through all of the
.Cm freebsd-ufs
partitions.
Boot behavior depends on the combination of
.Cm bootme
and
.Cm bootonce
attributes set on those partitions.
.Bl -tag -width ".Cm bootonce + .Cm bootme"
.It Cm bootonce + Cm bootme
Highest priority: booting is attempted from each of the
.Cm freebsd-ufs
partitions with both of these attributes.
On each partition, the
.Cm bootme
attribute is removed and the boot attempted.
.It Cm bootme
Middle priority: booting is attempted from each of the
.Cm freebsd-ufs
partitions with the
.Cm bootme
attribute.
.It neither
If neither
.Cm bootonce
nor
.Cm bootme
attributes are found on any partitions, booting is attempted from the
first
.Cm freebsd-ufs
partition on the disk.
.El
.Sh POST-BOOT ACTIONS
The startup script
.Pa /etc/rc.d/gptboot
checks the attributes of
.Cm freebsd-ufs
partitions on all GPT disks.
Partitions with the
.Cm bootfailed
attribute generate a
.Dq boot from X failed
system log message.
Partitions with only the
.Cm bootonce
attribute, indicating a partition that successfully booted, generate a
.Dq boot from X succeeded
system log message.
The
.Cm bootfailed
attributes are cleared from all the partitions.
The
.Cm bootonce
attribute is cleared from the partition that successfully booted.
There is normally only one of these.
.Sh FILES
.Bl -tag -width /boot/loader -compact
.It Pa /boot/gptboot
.It Pa /boot.config
.El
.Sh EXAMPLES
.Nm
is typically installed in combination with a
.Dq protective MBR
.Po
see
.Xr gpart 8
.Pc .
Install
.Nm
on the
.Pa ada0
drive:
.Bd -literal -offset indent
gpart bootcode -b /boot/pmbr -p /boot/gptboot -i 1 ada0
.Ed
.Pp
.Nm
can also be installed without the PMBR:
.Bd -literal -offset indent
gpart bootcode -p /boot/gptboot -i 1 ada0
.Ed
.Pp
Set the
.Cm bootme
attribute for partition 2:
.Bd -literal -offset indent
gpart set -a bootme -i 2 ada0
.Ed
.Pp
Set the
.Cm bootonce
attribute for partition 2, automatically also setting the
.Cm bootme
attribute:
.Bd -literal -offset indent
gpart set -a bootonce -i 2 ada0
.Ed
.Pp
.Sh SEE ALSO
.Xr boot.config 5 ,
.Xr rc.conf 5 ,
.Xr boot 8 ,
.Xr gpart 8
.Sh HISTORY
.Nm
appeared in FreeBSD 7.1.
.Sh AUTHORS
Warren Block <wblock@FreeBSD.org>