storage

Documentation

Index

• Constants
• Variables
• func GetGPTTable(device BlockDev) (*gpt.Table, error)
• func GetMountpointByDevice(devicePath string) (*string, error)
• func GetSupportedFilesystems() (fstypes []string, err error)
• type BlockDev
  • func FilterEFISystemPartitions(devices []BlockDev) ([]BlockDev, error)
  • func GetBlockStats() ([]BlockDev, error)
  • func PartitionsByFsUUID(devices []BlockDev, fsuuid string) []BlockDev
  • func PartitionsByGUID(devices []BlockDev, guid string) ([]BlockDev, error)
  • func (b BlockDev) Summary() string
• type BlockStat
  • func BlockStatFromBytes(buf []byte) (*BlockStat, error)
• type Mountpoint
  • func Mount(devname, mountpath string, filesystems []string) (*Mountpoint, error)

Constants

const (
	EXT2SprblkOff       = 1024 // Offset of superblock in partition
	EXT2SprblkSize      = 512  // Actually 1024 but most of the last byters are reserved
	EXT2SprblkMagicOff  = 56   // Offset of magic number in suberblock
	EXT2SprblkMagicSize = 2
	EXT2SprblkMagic     = '\uEF53' // fixed value
	EXT2SprblkUUIDOff   = 104      // Offset of UUID in superblock
	EXT2SprblkUUIDSize  = 16
)

see https://www.nongnu.org/ext2-doc/ext2.html#DISK-ORGANISATION

const (
	FAT32MagicOff  = 82 // Offset of magic number
	FAT32MagicSize = 8
	FAT32Magic     = "FAT32   " // fixed value
	FAT32IDOff     = 67         // Offset of filesystem-ID / serielnumber. Treated as short filesystem UUID
	FAT32IDSize    = 4
)

see https://de.wikipedia.org/wiki/File_Allocation_Table#Aufbau

Variables

var (
	// LinuxMountsPath is the standard mountpoint list path
	LinuxMountsPath = "/proc/mounts"
)

var SystemPartitionGUID = gpt.Guid([...]byte{
	0x28, 0x73, 0x2a, 0xc1,
	0x1f, 0xf8,
	0xd2, 0x11,
	0xba, 0x4b,
	0x00, 0xa0, 0xc9, 0x3e, 0xc9, 0x3b,
})

SystemPartitionGUID is the GUID of EFI system partitions EFI System partitions have GUID C12A7328-F81F-11D2-BA4B-00A0C93EC93B

Functions

func GetGPTTable

func GetGPTTable(device BlockDev) (*gpt.Table, error)

GetGPTTable tries to read a GPT table from the block device described by the passed BlockDev object, and returns a gpt.Table object, or an error if any

func GetMountpointByDevice

func GetMountpointByDevice(devicePath string) (*string, error)

GetMountpointByDevice gets the mountpoint by given device name. Returns on first match

func GetSupportedFilesystems

func GetSupportedFilesystems() (fstypes []string, err error)

GetSupportedFilesystems returns the supported file systems for block devices

Types

type BlockDev

type BlockDev struct {
	Name   string
	Stat   BlockStat
	FsUUID string
}

BlockDev maps a device name to a BlockStat structure for a given block device

func FilterEFISystemPartitions

func FilterEFISystemPartitions(devices []BlockDev) ([]BlockDev, error)

FilterEFISystemPartitions returns a list of BlockDev objects whose underlying block device is a valid EFI system partition, or an error if any

func GetBlockStats

func GetBlockStats() ([]BlockDev, error)

GetBlockStats iterates over /sys/class/block entries and returns a list of BlockDev objects, or an error if any

func PartitionsByFsUUID

func PartitionsByFsUUID(devices []BlockDev, fsuuid string) []BlockDev

PartitionsByFsUUID returns a list of BlockDev objects whose underlying block device has a filesystem with the given UUID

func PartitionsByGUID

func PartitionsByGUID(devices []BlockDev, guid string) ([]BlockDev, error)

PartitionsByGUID returns a list of BlockDev objects whose underlying block device has the given GUID

func (BlockDev) Summary

func (b BlockDev) Summary() string

Summary prints a multiline summary of the BlockDev object https://www.kernel.org/doc/Documentation/block/stat.txt

type BlockStat

type BlockStat struct {
	ReadIOs      uint64
	ReadMerges   uint64
	ReadSectors  uint64
	ReadTicks    uint64
	WriteIOs     uint64
	WriteMerges  uint64
	WriteSectors uint64
	WriteTicks   uint64
	InFlight     uint64
	IOTicks      uint64
	TimeInQueue  uint64
	// Kernel 4.18 added four fields for discard tracking, see
	// https://github.com/torvalds/linux/commit/bdca3c87fb7ad1cc61d231d37eb0d8f90d001e0c
	DiscardIOs     uint64
	DiscardMerges  uint64
	DiscardSectors uint64
	DiscardTicks   uint64
}

BlockStat provides block device information as contained in /sys/class/block/<device_name>/stat

func BlockStatFromBytes

func BlockStatFromBytes(buf []byte) (*BlockStat, error)

BlockStatFromBytes parses a block stat file and returns a BlockStat object. The format of the block stat file is the one defined by Linux for /sys/class/block/<device_name>/stat

type Mountpoint

type Mountpoint struct {
	DeviceName string
	Path       string
	FsType     string
}

Mountpoint holds mount point information for a given device

func Mount

func Mount(devname, mountpath string, filesystems []string) (*Mountpoint, error)

Mount tries to mount a block device on the given mountpoint, trying in order the provided file system types. It returns a Mountpoint structure, or an error if the device could not be mounted. If the mount point does not exist, it will be created.