image

package
v1.3.1 Latest Latest
Warning

This package is not in the latest version of its module.

 Go to latest Published: Apr 24, 2024 License: BSD-3-Clause Imports: 18 Imported by: 0

Documentation

Overview

Package image provides underlying data types for Apptainer image formats. Additionally, all image types will satisfy the ImageFormat{} interface. This interface will expose all things necessary to use an Apptainer image, whether through OCI or directly. 

type ImageFormat interface {
    Root() *spec.Root - Root() returns the OCI compliant root of the
                        Image. This function may perform some action,
                        such as extracting the filesystem to a dir.
}

Index

Constants

View Source 
const (
	// SQUASHFS constant for squashfs format
	SQUASHFS = iota + 0x1000
	// EXT3 constant for ext3 format
	EXT3
	// SANDBOX constant for directory format
	SANDBOX
	// SIF constant for sif format
	SIF
	// ENCRYPTSQUASHFS constant for encrypted squashfs format
	ENCRYPTSQUASHFS
	// RAW constant for raw format
	RAW
	// GOCRYPTFS constant for encrypted gocryptfs format
	GOCRYPTFSSQUASHFS
)
View Source 
const (
	// RootFsUsage defines flag for image/partition
	// usable as root filesystem.
	RootFsUsage = Usage(1 << iota)
	// OverlayUsage defines flag for image/partition
	// usable as overlay.
	OverlayUsage
	// DataUsage defines flag for image/partition
	// usable as data.
	DataUsage
)
View Source 
const (
	// ErrNoSection corresponds to an image section not found.
	ErrNoSection = readerError("no section found")
	// ErrNoPartition corresponds to an image partition not found.
	ErrNoPartition = readerError("no partition found")
)
View Source 
const (
	// SIFDescOCIConfigJSON is the name of the SIF descriptor holding the OCI configuration.
	SIFDescOCIConfigJSON = "oci-config.json"
	// SIFDescInspectMetadataJSON is the name of the SIF descriptor holding the container metadata.
	SIFDescInspectMetadataJSON = "inspect-metadata.json"
)
View Source 
const ImageFeature = SquashFeature | Ext3Feature | GocryptFeature

ImageFeature means the driver handles any of the image mount types

View Source 
const (
	// RootFs partition name
	RootFs = "!__rootfs__!"
)

Variables

View Source 
var ErrUnknownFormat = errors.New("image format not recognized")

ErrUnknownFormat represents an unknown image format error.

Functions

func CheckExt3Header 

func CheckExt3Header(b []byte) (uint64, error)

CheckExt3Header checks if byte content contains a valid ext3 header and returns offset where ext3 partition begin

func CheckSquashfsHeader 

func CheckSquashfsHeader(b []byte) (uint64, error)

CheckSquashfsHeader checks if byte content contains a valid squashfs header and returns offset where squashfs partition starts

func GetSquashfsComp 

func GetSquashfsComp(b []byte) (string, error)

GetSquashfsComp checks if byte content contains a valid squashfs header and returns type of compression used

func IsReadOnlyFilesytem 

func IsReadOnlyFilesytem(err error) bool

IsReadOnlyFilesytem returns if the corresponding error is a read-only filesystem error or not.

func NewPartitionReader 

func NewPartitionReader(image *Image, name string, index int) (io.Reader, error)

NewPartitionReader searches and returns a reader for an image partition identified by name or by index, if index is less than 0 only partition with provided name will be returned if a matching entry is found

func NewSectionReader 

func NewSectionReader(image *Image, name string, index int) (io.Reader, error)

NewSectionReader searches and returns a reader for an image section identified by name or by index, if index is less than 0 only section with provided name will be returned if a matching entry is found.

func RegisterDriver 

func RegisterDriver(name string, driver Driver) error

RegisterDriver registers an image driver by name.

func ResolvePath 

func ResolvePath(path string) (string, error)

ResolvePath returns a resolved absolute path.

Types

type Driver 

type Driver interface {
	// Mount is called each time an engine mount an image
	Mount(*MountParams, MountFunc) error
	// MountErr returns driver mount errors.
	MountErr() error
	// Start the driver for initialization.
	Start(*DriverParams, int, bool) error
	// Stop the driver related to given mount target for cleanup,
	// an empty target signify to the driver to prepare for stop.
	Stop(string) error
	// Features Feature returns supported features.
	Features() DriverFeature
}

Driver defines the image driver interface to register.

func GetDriver 

func GetDriver(name string) Driver

GetDriver returns the named image driver interface.

type DriverFeature 

type DriverFeature uint16

DriverFeature defines a feature type that a driver is supporting. 

const (
	// SquashFeature means the driver handles squashfs image mounts.
	SquashFeature DriverFeature = 1 << iota
	// Ext3Feature means the driver handles ext3fs image mounts.
	Ext3Feature
	// GocryptFeature means the driver handles gocryptfs image mounts.
	GocryptFeature
	// OverlayFeature means the driver handle overlay mount.
	OverlayFeature
	// FuseFeature means the driver uses FUSE as its base.
	FuseFeature
)

type DriverParams 

type DriverParams struct {
	SessionPath string         // session driver image path
	UsernsFd    int            // user namespace file descriptor
	FuseFd      int            // fuse file descriptor
	Config      *config.Common // common engine configuration
}

DriverParams defines parameters passed to driver interface while starting it.

type Image 

type Image struct {
	Partitions []Section `json:"partitions"`
	Sections   []Section `json:"sections"`
	Path       string    `json:"path"`
	Name       string    `json:"name"`
	Source     string    `json:"source"`
	Type       int       `json:"type"`
	File       *os.File  `json:"-"`
	Fd         uintptr   `json:"fd"`
	Writable   bool      `json:"writable"`
	Usage      Usage     `json:"usage"`
}

Image describes an image object, an image is composed of one or more partitions (eg: container root filesystem, overlay), image format like SIF contains descriptors pointing to chunk of data, chunks position and size are stored as image sections.

func Init 

func Init(path string, writable bool) (*Image, error)

Init initializes an image object based on given path.

func (*Image) AuthorizedGroup 

func (i *Image) AuthorizedGroup(groups []string) (bool, error)

AuthorizedGroup checks whether the image is owned by any group from the supplied groups list.

func (*Image) AuthorizedOwner 

func (i *Image) AuthorizedOwner(owners []string) (bool, error)

AuthorizedOwner checks whether the image is owned by any user from the supplied users list.

func (*Image) AuthorizedPath 

func (i *Image) AuthorizedPath(paths []string) (bool, error)

AuthorizedPath checks if image is in a path supplied in paths

func (*Image) EncryptedRootFs added in v1.3.0 

func (i *Image) EncryptedRootFs() (encryptionType string, err error)

EncryptedRootFs returns "encryptfs" if the image contains a device-mapper encrypted root partition, "gocryptfs" if it contains a gocryptfs encrypted root partition, or an empty string if there is no encryption

func (*Image) GetAllPartitions 

func (i *Image) GetAllPartitions() ([]Section, error)

GetAllPartitions returns all partitions found in the image.

func (*Image) GetDataPartitions 

func (i *Image) GetDataPartitions() ([]Section, error)

GetDataPartitions returns data partitions found in the image.

func (*Image) GetOverlayPartitions 

func (i *Image) GetOverlayPartitions() ([]Section, error)

GetOverlayPartitions returns overlay partitions found in the image.

func (*Image) GetRootFsPartition 

func (i *Image) GetRootFsPartition() (*Section, error)

GetRootFsPartition returns the first root filesystem partition found in the image.

func (*Image) GetRootFsPartitions 

func (i *Image) GetRootFsPartitions() ([]Section, error)

GetRootFsPartitions returns root filesystem partitions found in the image.

func (*Image) ReInit 

func (i *Image) ReInit()

ReInit fills in the File object if needed. This function should be called after passing an image object between processes using JSON

type MountFunc 

type MountFunc func(source string, target string, filesystem string, flags uintptr, data string) error

MountFunc defines mount function prototype

type MountParams 

type MountParams struct {
	Source           string   // image source
	Target           string   // image target mount point
	Filesystem       string   // image filesystem type
	Flags            uintptr  // mount flags
	Offset           uint64   // offset where start filesystem
	Size             uint64   // size of image filesystem
	Key              []byte   // filesystem decryption key
	FSOptions        []string // filesystem mount options
	DontElevatePrivs bool     // omit cmd.SysProcAttr, currently only used by gocryptfs
}

MountParams defines parameters passed to driver interface while mounting images.

type Section 

type Section struct {
	Name         string `json:"name"`
	Size         uint64 `json:"size"`
	Offset       uint64 `json:"offset"`
	ID           uint32 `json:"id"`
	Type         uint32 `json:"type"`
	AllowedUsage Usage  `json:"allowed_usage"`
}

Section identifies and locates a data section in image object.

type Usage 

type Usage uint8

Source Files

View all Source files

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL
go.dev uses cookies from Google to deliver and enhance the quality of its services and to analyze traffic. Learn more.