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.. SPDX-License-Identifier: GPL-2.0+
gpt command
===========
Synopsis
--------
::
gpt enumerate <interface> <dev>
gpt guid <interface> <dev> [<varname>]
gpt read <interface> <dev> [<varname>]
gpt rename <interface> <dev> <part> <name>
gpt repair <interface> <dev>
gpt setenv <interface> <dev> <partition name>
gpt swap <interface> <dev> <name1> <name2>
gpt verify <interface> <dev> [<partition string>]
gpt write <interface> <dev> <partition string>
Description
-----------
The gpt command lets users read, create, modify, or verify the GPT (GUID
Partition Table) partition layout.
Common arguments:
interface
interface for accessing the block device (mmc, sata, scsi, usb, ....)
dev
device number
partition string
Describes the GPT partition layout for a disk. The syntax is similar to
the one used by the :doc:`mbr command <mbr>` command. The string contains
one or more partition descriptors, each separated by a ";". Each descriptor
contains one or more fields, with each field separated by a ",". Fields are
either of the form "key=value" to set a specific value, or simple "flag" to
set a boolean flag
The first descriptor can optionally be used to describe parameters for the
whole disk with the following fields:
* uuid_disk=UUID - Set the UUID for the disk
Partition descriptors can have the following fields:
* name=<NAME> - The partition name, required
* start=<BYTES> - The partition start offset in bytes, required
* size=<BYTES> - The partition size in bytes or "-" to expand it to the whole free area
* bootable - Set the legacy bootable flag
* uuid=<UUID> - The partition UUID, optional if CONFIG_RANDOM_UUID=y is enabled
* type=<UUID> - The partition type GUID, requires CONFIG_PARTITION_TYPE_GUID=y
If 'uuid' is not specified, but CONFIG_RANDOM_UUID is enabled, a random UUID
will be generated for the partition
gpt enumerate
~~~~~~~~~~~~~
Sets the variable 'gpt_partition_list' to be a list of all the partition names
on the device.
gpt guid
~~~~~~~~
Report the GUID of a disk. If 'varname' is specified, the command will set the
variable to the GUID, otherwise it will be printed out.
gpt read
~~~~~~~~
Prints the current state of the GPT partition table. If 'varname' is specified,
the variable will be filled with a partition string in the same format as a
'<partition string>', suitable for passing to other 'gpt' commands. If the
argument is omitted, a human readable description is printed out.
CONFIG_CMD_GPT_RENAME=y is required.
gpt rename
~~~~~~~~~~
Renames all partitions named 'part' to be 'name'. CONFIG_CMD_GPT_RENAME=y is
required.
gpt repair
~~~~~~~~~~
Repairs the GPT partition tables if it they become corrupted.
gpt setenv
~~~~~~~~~~
The 'gpt setenv' command will set a series of environment variables with
information about the partition named '<partition name>'. The variables are:
gpt_partition_addr
the starting offset of the partition in blocks as a hexadecimal number
gpt_partition_size
the size of the partition in blocks as a hexadecimal number
gpt_partition_name
the name of the partition
gpt_partition_entry
the partition number in the table, e.g. 1, 2, 3, etc.
gpt swap
~~~~~~~~
Changes the names of all partitions that are named 'name1' to be 'name2', and
all partitions named 'name2' to be 'name1'. CONFIG_CMD_GPT_RENAME=y is
required.
gpt verify
~~~~~~~~~~
Sets return value $? to 0 (true) if the partition layout on the
specified disk matches the one in the provided partition string, and 1 (false)
if it does not match. If no partition string is specified, the command will
check if the disk is partitioned or not.
gpt write
~~~~~~~~~
(Re)writes the partition table on the disk to match the provided
partition string. It returns 0 on success or 1 on failure.
Configuration
-------------
To use the 'gpt' command you must specify CONFIG_CMD_GPT=y. To enable 'gpt
read', 'gpt swap' and 'gpt rename', you must specify CONFIG_CMD_GPT_RENAME=y.
Examples
~~~~~~~~
Create 6 partitions on a disk::
=> setenv gpt_parts 'uuid_disk=bec9fc2a-86c1-483d-8a0e-0109732277d7;
name=boot,start=4M,size=128M,bootable,type=ebd0a0a2-b9e5-4433-87c0-68b6b72699c7,
name=rootfs,size=3072M,type=0fc63daf-8483-4772-8e79-3d69d8477de4;
name=system-data,size=512M,type=0fc63daf-8483-4772-8e79-3d69d8477de4;
name=[ext],size=-,type=0fc63daf-8483-4772-8e79-3d69d8477de4;
name=user,size=-,type=0fc63daf-8483-4772-8e79-3d69d8477de4;
name=modules,size=100M,type=0fc63daf-8483-4772-8e79-3d69d8477de4;
name=ramdisk,size=8M,type=0fc63daf-8483-4772-8e79-3d69d8477de4
=> gpt write mmc 0 $gpt_parts
Verify that the device matches the partition layout described in the variable
$gpt_parts::
=> gpt verify mmc 0 $gpt_parts
Get the information about the partition named 'rootfs'::
=> gpt setenv mmc 0 rootfs
=> echo ${gpt_partition_addr}
2000
=> echo ${gpt_partition_size}
14a000
=> echo ${gpt_partition_name}
rootfs
=> echo ${gpt_partition_entry}
2
Get the list of partition names on the disk::
=> gpt enumerate
=> echo gpt_partition_list
boot rootfs system-data [ext] user modules ramdisk
Get the GUID for a disk::
=> gpt guid mmc 0
bec9fc2a-86c1-483d-8a0e-0109732277d7
=> gpt guid mmc gpt_disk_uuid
=> echo ${gpt_disk_uuid}
bec9fc2a-86c1-483d-8a0e-0109732277d7
|
