package format

import "github.com/Microsoft/hcsshim/pkg/cimfs/format"

format package maintains some basic structures to allows us to read header of a cim file. This is mostly required to understand the region & objectid files associated with a particular cim. Otherwise, we don't need to parse the cim format.

Index ¶

• Constants
• Variables
• type CommonHeader
• type FileType
• type FilesystemHeader
• type Magic
• type RegionOffset
• type RegionSet
• type Version

Constants ¶

const (
	RegionFileName   = "region"
	ObjectIDFileName = "objectid"
)

Variables ¶

var CurrentVersion = Version{3, 0}

var MagicValue = Magic([8]uint8{'c', 'i', 'm', 'f', 'i', 'l', 'e', '0'})

var MinSupportedVersion = Version{2, 0}

Types ¶

type CommonHeader ¶

type CommonHeader struct {
	Magic        Magic
	HeaderLength uint32
	Type         FileType
	Reserved     uint8
	Reserved2    uint16
	Version      Version
	Reserved3    uint64
}

CommonHeader is the common header for all CIM-related files.

type FileType ¶

type FileType uint8

type FilesystemHeader ¶

type FilesystemHeader struct {
	Common           CommonHeader
	Regions          RegionSet
	FilesystemOffset RegionOffset
	Reserved         uint32
	Reserved1        uint16
	ParentCount      uint16
}

FilesystemHeader is the header for a filesystem file.

The filesystem file points to the filesystem object inside a region file and specifies regions sets.

type Magic ¶

type Magic [8]uint8

Magic specifies the magic number at the beginning of a file.

type RegionOffset ¶

type RegionOffset uint64

RegionOffset encodes an offset to objects as index of the region file containing the object and the byte offset within that file.

type RegionSet ¶

type RegionSet struct {
	ID        guid.GUID
	Count     uint16
	Reserved  uint16
	Reserved1 uint32
}

type Version ¶

type Version struct {
	Major, Minor uint32
}

Source Files ¶

doc.go format.go