gpt

package
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 Go to latest Published: Jul 19, 2026 License: MIT Imports: 12 Imported by: 24

Documentation

Overview

Package gpt provides an interface to GUID Partition Table (GPT) partitioned disks.

You can use this package to manipulate existing GPT disks, read existing disks, or create entirely new partition tables on disks or disk files.

gpt.Table implements the Table interface in github.com/diskfs/go-diskfs/partition

Normally, the best way to interact with a disk is to use the github.com/diskfs/go-diskfs package, which, when necessary, will call this one. When creating a new disk or manipulating an existing one, You will, however, need to interact with an gpt.Table and gpt.Partition structs.

Here is a simple example of a GPT Table with a single 10MB Linux partition: 

table := &gpt.Table{
  LogicalSectorSize:  512,
  PhysicalSectorSize: 512,
  Partitions: []*mbr.Partition{
    {
      LogicalSectorSize:  512,
      PhysicalSectorSize: 512,
      ProtectiveMBR:      true,
      GUID:               "43E51892-3273-42F7-BCDA-B43B80CDFC48",
    },
  },
}

Index

Constants

View Source 
const PartitionEntrySize = 128

PartitionEntrySize fixed size of a GPT partition entry

Variables

This section is empty.

Functions

This section is empty.

Types

type Partition 

type Partition struct {
	Index      int    // index of the partition in the table
	Start      uint64 // start sector for the partition
	End        uint64 // end sector for the partition
	Size       uint64 // size of the partition in bytes
	Type       Type   // parttype for the partition
	Name       string // name for the partition
	GUID       string // partition GUID, can be left blank to auto-generate
	Attributes uint64 // Attributes flags
	// contains filtered or unexported fields
}

Partition represents the structure of a single partition on the disk

func (*Partition) Equal added in v1.3.0 

func (p *Partition) Equal(o *Partition) bool

func (*Partition) Expand added in v1.4.1 

func (p *Partition) Expand(sectors uint64)

Expand increases the size of the partition by a number of sectors

func (*Partition) GetIndex added in v1.8.0 

func (p *Partition) GetIndex() int

func (*Partition) GetSize added in v1.1.0 

func (p *Partition) GetSize() int64

func (*Partition) GetStart added in v1.1.0 

func (p *Partition) GetStart() int64

func (*Partition) Label added in v1.8.0 

func (p *Partition) Label() string

Label returns the partition label

func (*Partition) ReadContents added in v1.1.0 

func (p *Partition) ReadContents(f backend.File, out io.Writer) (int64, error)

ReadContents reads the contents of the partition into a writer streams the entire partition to the writer

func (*Partition) UUID added in v1.4.1 

func (p *Partition) UUID() string

UUID returns the partitions UUID

func (*Partition) WriteContents added in v1.1.0 

func (p *Partition) WriteContents(f backend.WritableFile, contents io.Reader) (uint64, error)

WriteContents fills the partition with the contents provided reads from beginning of reader to exactly size of partition in bytes

type Table 

type Table struct {
	Partitions         []*Partition // slice of Partition
	LogicalSectorSize  int          // logical size of a sector
	PhysicalSectorSize int          // physical size of the sector
	GUID               string       // disk GUID, can be left blank to auto-generate
	ProtectiveMBR      bool         // whether or not a protective MBR is in place
	// RecoveredFromBackup is set to true by Read() when the primary GPT was
	// invalid (bad signature / header CRC / partition-entries CRC) and the
	// table was loaded from the backup GPT at end-of-disk. Callers should
	// rewrite the primary by calling Write() with this table, or use an
	// external tool such as sgdisk --repair, before treating subsequent
	// reads as authoritative.
	RecoveredFromBackup bool
	// contains filtered or unexported fields
}

Table represents a partition table to be applied to a disk or read from a disk

func Read 

func Read(f backend.File, logicalBlockSize, physicalBlockSize int) (*Table, error)

Read reads a partition table from a disk.

Must be passed the backend.File from which to read, and the logical and physical block sizes. If successful, returns a gpt.Table struct. Returns an error if it fails at any stage reading the disk or processing the bytes on disk as a GPT.

If the primary GPT (LBA 1) parses and reads cleanly but fails CRC validation (header CRC or partition-entries CRC), Read falls back to the backup GPT at end-of-disk. On a successful fallback the returned Table has RecoveredFromBackup set to true; the caller should rewrite the primary by calling Write() before treating subsequent reads as authoritative.

I/O errors on the primary (read failure, short read) are propagated directly without a backup attempt, because the backup is read through the same I/O path and would fail the same way. Callers that want to retry with a different reader can detect this case by inspecting the returned error.

func (*Table) Equal 

func (t *Table) Equal(t2 *Table) bool

Equal check if another table is functionally equal to this one

func (*Table) GetPartitions added in v1.1.0 

func (t *Table) GetPartitions() []part.Partition

GetPartitions get the partitions

func (*Table) LastDataSector added in v1.4.1 

func (t *Table) LastDataSector() uint64

func (*Table) Repair added in v1.4.1 

func (t *Table) Repair(diskSize uint64) error

Repair will attempt to evaluate the headers fix the header location and re-write the primary and secondary header

func (*Table) Resize added in v1.4.1 

func (t *Table) Resize(size uint64)

Resize changes the size of the GPT.

The size argument is in bytes and must be a multiple of the logical sector size. Use this function in case a storage device is not the same as the total size of its GPT.

func (*Table) TotalSize added in v1.4.1 

func (t *Table) TotalSize() uint64

TotalSize returns the total size of the GPT in bytes.

This is counted from the start of the MBR to the end of the secondary header.

func (*Table) Type 

func (t *Table) Type() string

Type report the type of table, always "gpt"

func (*Table) UUID added in v1.4.1 

func (t *Table) UUID() string

UUID returns the partition table UUID (disk UUID)

func (*Table) Verify added in v1.4.1 

func (t *Table) Verify(f backend.File, diskSize uint64) error

Verify will attempt to evaluate the headers

func (*Table) Write 

func (t *Table) Write(f backend.WritableFile, size int64) error

Write writes a GPT to disk. Must be passed the backend.WritableFile to which to write and the size of the disk.

Write order is designed to be crash-safe: the backup GPT (at end of disk) is written and synced before the primary GPT (at LBA 1). Within each side, the partition-entries array is written and synced before the header sector that references its CRC. A power loss at any point leaves the disk in one of:

  • both copies still old (operation not yet observably started),
  • backup new, primary still old,
  • backup new, primary inconsistent (CRC mismatch — Read() falls back to the backup),
  • both copies fully new (success).

In every case, a consumer that validates CRCs and falls back to the backup on primary failure will see a consistent partition layout.

type Type 

type Type string

Type constants for the GUID for type of partition, see https://en.wikipedia.org/wiki/GUID_Partition_Table#Partition_entries 

const (
	Unused                   Type = "00000000-0000-0000-0000-000000000000"
	EFISystemPartition       Type = "C12A7328-F81F-11D2-BA4B-00A0C93EC93B"
	MBRPartitionScheme       Type = "024DEE41-33E7-11D3-9D69-0008C781F39F"
	IntelFastFlash           Type = "D3BFE2DE-3DAF-11DF-BA40-E3A556D89593"
	BIOSBoot                 Type = "21686148-6449-6E6F-744E-656564454649"
	SonyBootPartition        Type = "F4019732-066E-4E12-8273-346C5641494F"
	LenovoBootPartition      Type = "BFBFAFE7-A34F-448A-9A5B-6213EB736C22"
	PowerPCPRePBoot          Type = "9E1A2D38-C612-4316-AA26-8B49521E5A8B"
	ONIEBoot                 Type = "7412F7D5-A156-4B13-81DC-867174929325"
	ONIEConfig               Type = "D4E6E2CD-4469-46F3-B5CB-1BFF57AFC149"
	MicrosoftReserved        Type = "E3C9E316-0B5C-4DB8-817D-F92DF00215AE"
	MicrosoftBasicData       Type = "EBD0A0A2-B9E5-4433-87C0-68B6B72699C7"
	MicrosoftLDMMetadata     Type = "5808C8AA-7E8F-42E0-85D2-E1E90434CFB3"
	MicrosoftLDMData         Type = "AF9B60A0-1431-4F62-BC68-3311714A69AD"
	MicrosoftWindowsRecovery Type = "DE94BBA4-06D1-4D40-A16A-BFD50179D6AC"
	IBMGeneralParallelFs     Type = "37AFFC90-EF7D-4E96-91C3-2D7AE055B174"
	MicrosoftStorageSpaces   Type = "E75CAF8F-F680-4CEE-AFA3-B001E56EFC2D"
	HPUXData                 Type = "75894C1E-3AEB-11D3-B7C1-7B03A0000000"
	HPUXService              Type = "E2A1E728-32E3-11D6-A682-7B03A0000000"
	LinuxSwap                Type = "0657FD6D-A4AB-43C4-84E5-0933C84B4F4F"
	LinuxFilesystem          Type = "0FC63DAF-8483-4772-8E79-3D69D8477DE4"
	LinuxServerData          Type = "3B8F8425-20E0-4F3B-907F-1A25A76F98E8"
	LinuxRootX86             Type = "44479540-F297-41B2-9AF7-D131D5F0458A"
	LinuxRootArm             Type = "69DAD710-2CE4-4E3C-B16C-21A1D49ABED3"
	LinuxRootX86_64          Type = "4F68BCE3-E8CD-4DB1-96E7-FBCAF984B709"
	LinuxRootArm64           Type = "B921B045-1DF0-41C3-AF44-4C6F280D3FAE"
	LinuxRootIA64            Type = "993D8D3D-F80E-4225-855A-9DAF8ED7EA97"
	LinuxReserved            Type = "8DA63339-0007-60C0-C436-083AC8230908"
	LinuxHome                Type = "933AC7E1-2EB4-4F13-B844-0E14E2AEF915"
	LinuxRAID                Type = "A19D880F-05FC-4D3B-A006-743F0F84911E"
	LinuxExtendedBoot        Type = "BC13C2FF-59E6-4262-A352-B275FD6F7172"
	LinuxLVM                 Type = "E6D6D379-F507-44C2-A23C-238F2A3DF928"
	LinuxDMCrypt             Type = "7FFEC5C9-2D00-49B7-8941-3EA10A5586B7"
	LinuxLUKS                Type = "CA7D7CCB-63ED-4C53-861C-1742536059CC"
	FreeBSDData              Type = "516E7CB4-6ECF-11D6-8FF8-00022D09712B"
	FreeBSDBoot              Type = "83BD6B9D-7F41-11DC-BE0B-001560B84F0F"
	FreeBSDSwap              Type = "516E7CB5-6ECF-11D6-8FF8-00022D09712B"
	FreeBSDNANDFS            Type = "74BA7DD9-A689-11E1-BD04-00E081286ACF"
	FreeBSDUFS               Type = "516E7CB6-6ECF-11D6-8FF8-00022D09712B"
	FreeBSDZFS               Type = "516E7CBA-6ECF-11D6-8FF8-00022D09712B"
	FreeBSDVinum             Type = "516E7CB8-6ECF-11D6-8FF8-00022D09712B"
	AppleHFS                 Type = "48465300-0000-11AA-AA11-00306543ECAC"
	AppleUFS                 Type = "55465300-0000-11AA-AA11-00306543ECAC"
	AppleAPFS                Type = "7C3457EF-0000-11AA-AA11-00306543ECAC"
	AppleRAID                Type = "52414944-0000-11AA-AA11-00306543ECAC"
	AppleRAIDOffline         Type = "52414944-5F4F-11AA-AA11-00306543ECAC"
	AppleBoot                Type = "426F6F74-0000-11AA-AA11-00306543ECAC"
	AppleLabel               Type = "4C616265-6C00-11AA-AA11-00306543ECAC"
	AppleTVRecovery          Type = "5265636F-7665-11AA-AA11-00306543ECAC"
	AppleCoreStorage         Type = "53746F72-6167-11AA-AA11-00306543ECAC"
	DragonflyLabel32         Type = "9D087404-1CA5-11DC-8817-01301BB8A9F5"
	DragonflySwap            Type = "9D58FDBD-1CA5-11DC-8817-01301BB8A9F5"
	DragonflyUFS             Type = "9D94CE7C-1CA5-11DC-8817-01301BB8A9F5"
	DragonflyVINUM           Type = "9DD4478F-1CA5-11DC-8817-01301BB8A9F5"
	DragonflyCCD             Type = "DBD5211B-1CA5-11DC-8817-01301BB8A9F5"
	DragonflyLabel64         Type = "3D48CE54-1D16-11DC-8696-01301BB8A9F5"
	DragonflyLegacy          Type = "BD215AB2-1D16-11DC-8696-01301BB8A9F5"
	DragonflyHAMMER          Type = "61DC63AC-6E38-11DC-8513-01301BB8A9F5"
	DragonflyHAMMER2         Type = "5CBB9AD1-862D-11DC-A94D-01301BB8A9F5"
	SolarisBoot              Type = "6A82CB45-1DD2-11B2-99A6-080020736631"
	SolarisRoot              Type = "6A85CF4D-1DD2-11B2-99A6-080020736631"
	SolarisUsrAndAppleZFS    Type = "6A898CC3-1DD2-11B2-99A6-080020736631"
	SolarisSwap              Type = "6A87C46F-1DD2-11B2-99A6-080020736631"
	SolarisBackup            Type = "6A8B642B-1DD2-11B2-99A6-080020736631"
	SolarisVar               Type = "6A8EF2E9-1DD2-11B2-99A6-080020736631"
	SolarisHome              Type = "6A90BA39-1DD2-11B2-99A6-080020736631"
	SolarisAlternateSector   Type = "6A9283A5-1DD2-11B2-99A6-080020736631"
	SolarisReserved1         Type = "6A945A3B-1DD2-11B2-99A6-080020736631"
	SolarisReserved2         Type = "6A9630D1-1DD2-11B2-99A6-080020736631"
	SolarisReserved3         Type = "6A980767-1DD2-11B2-99A6-080020736631"
	SolarisReserved4         Type = "6A96237F-1DD2-11B2-99A6-080020736631"
	SolarisReserved5         Type = "6A8D2AC7-1DD2-11B2-99A6-080020736631"
	NetBSDSwap               Type = "49F48D32-B10E-11DC-B99B-0019D1879648"
	NetBSDFFS                Type = "49F48D5A-B10E-11DC-B99B-0019D1879648"
	NetBSDLFS                Type = "49F48D82-B10E-11DC-B99B-0019D1879648"
	NetBSDConcatenated       Type = "2DB519C4-B10E-11DC-B99B-0019D1879648"
	NetBSDEncrypted          Type = "2DB519EC-B10E-11DC-B99B-0019D1879648"
	NetBSDRAID               Type = "49F48DAA-B10E-11DC-B99B-0019D1879648"
	ChromeOSFirmware         Type = "CAB6E88E-ABF3-4102-A07A-D4BB9BE3C1D3"
	ChromeOSKernel           Type = "FE3A2A5D-4F32-41A7-B725-ACCC3285A309"
	ChromeOSRootFs           Type = "3CB8E202-3B7E-47DD-8A3C-7FF2A13CFCEC"
	ChromeOSReserved         Type = "2E0A753D-9E48-43B0-8337-B15192CB1B5E"
	MidnightBSDData          Type = "85D5E45A-237C-11E1-B4B3-E89A8F7FC3A7"
	MidnightBSDBoot          Type = "85D5E45E-237C-11E1-B4B3-E89A8F7FC3A7"
	MidnightBSDSwap          Type = "85D5E45B-237C-11E1-B4B3-E89A8F7FC3A7"
	MidnightBSDUFS           Type = "0394EF8B-237E-11E1-B4B3-E89A8F7FC3A7"
	MidnightBSDZFS           Type = "85D5E45D-237C-11E1-B4B3-E89A8F7FC3A7"
	MidnightBSDVinum         Type = "85D5E45C-237C-11E1-B4B3-E89A8F7FC3A7"
	CephJournal              Type = "45B0969E-9B03-4F30-B4C6-B4B80CEFF106"
	CephEncryptedJournal     Type = "45B0969E-9B03-4F30-B4C6-5EC00CEFF106"
	CephOSD                  Type = "4FBD7E29-9D25-41B8-AFD0-062C0CEFF05D"
	CephCryptOSD             Type = "4FBD7E29-9D25-41B8-AFD0-5EC00CEFF05D"
	CephDiskInCreation       Type = "89C57F98-2FE5-4DC0-89C1-F3AD0CEFF2BE"
	CephCryptDiskInCreation  Type = "89C57F98-2FE5-4DC0-89C1-5EC00CEFF2BE"
	VMwareVMFS               Type = "AA31E02A-400F-11DB-9590-000C2911D1B8"
	VMwareDiagnostic         Type = "9D275380-40AD-11DB-BF97-000C2911D1B8"
	VMwareVirtualSAN         Type = "381CFCCC-7288-11E0-92EE-000C2911D0B2"
	VMwareVirsto             Type = "77719A0C-A4A0-11E3-A47E-000C29745A24"
	VMwareReserved           Type = "9198EFFC-31C0-11DB-8F78-000C2911D1B8"
	OpenBSDData              Type = "824CC7A0-36A8-11E3-890A-952519AD3F61"
	QNX6FileSystem           Type = "CEF5A9AD-73BC-4601-89F3-CDEEEEE321A1"
	Plan9Partition           Type = "C91818F9-8025-47AF-89D2-F030D7000C2C"
	HiFiveUnleashedFSBL      Type = "5B193300-FC78-40CD-8002-E86C45580B47"
	HiFiveUnleashedBBL       Type = "2E54B353-1271-4842-806F-E436D6AF6985"
)

List of GUID partition types

Source Files

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