gadget

package
v0.1.0 Latest Latest
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 Go to latest Published: Nov 12, 2022 License: Apache-2.0 Imports: 29 Imported by: 0

Documentation

Index

Constants

View Source 
const (
	SystemBoot = "system-boot"
	SystemData = "system-data"
	SystemSeed = "system-seed"
	SystemSave = "system-save"
)
View Source 
const (
	// SizeMBR is the maximum byte size of a structure of role 'mbr'
	SizeMBR = quantity.Size(446)
	// SizeLBA48Pointer is the byte size of a pointer value written at the
	// location described by 'offset-write'
	SizeLBA48Pointer = quantity.Size(4)
)
View Source 
const (
	ContentWrite ContentOperation = iota
	ContentUpdate
	ContentRollback

	ChangeAbort ContentChangeAction = iota
	ChangeApply
	ChangeIgnore
)
View Source 
const GPTPartitionGUIDESP = "C12A7328-F81F-11D2-BA4B-00A0C93EC93B"

Variables

View Source 
var (
	ErrDeviceNotFound      = errors.New("device not found")
	ErrMountNotFound       = errors.New("mount point not found")
	ErrNoFilesystemDefined = errors.New("no filesystem defined")
)
View Source 
var (
	// default positioning constraints that match ubuntu-image
	DefaultConstraints = LayoutConstraints{
		NonMBRStartOffset: 1 * quantity.OffsetMiB,
	}
)
View Source 
var ErrNoKernelCommandline = errors.New("no kernel command line in the gadget")
View Source 
var (
	ErrNoUpdate = errors.New("nothing to update")
)

Functions

func AllDiskVolumeDeviceTraits 

func AllDiskVolumeDeviceTraits(allLaidOutVols map[string]*LaidOutVolume, optsPerVolume map[string]*DiskVolumeValidationOptions) (map[string]DiskVolumeDeviceTraits, error)

AllDiskVolumeDeviceTraits takes a mapping of volume name to LaidOutVolume and produces a map of volume name to DiskVolumeDeviceTraits. Since doing so uses DiskVolumeDeviceTraitsForDevice, it will also validate that disk devices identified for the laid out volume are compatible and matching before returning.

func EnsureLayoutCompatibility 

func EnsureLayoutCompatibility(gadgetLayout *LaidOutVolume, diskLayout *OnDiskVolume, opts *EnsureLayoutCompatibilityOptions) error

func FindDeviceForStructure 

func FindDeviceForStructure(ps *LaidOutStructure) (string, error)

FindDeviceForStructure attempts to find an existing block device matching given volume structure, by inspecting its name and, optionally, the filesystem label. Assumes that the host's udev has set up device symlinks correctly.

func IsCompatible 

func IsCompatible(current, new *Info) error

IsCompatible checks whether the current and an update are compatible. Returns nil or an error describing the incompatibility. TODO: make this reasonably consistent with Update for multi-volume scenarios

func IsCreatableAtInstall 

func IsCreatableAtInstall(gv *VolumeStructure) bool

IsCreatableAtInstall returns whether the gadget structure would be created at install - currently that is only ubuntu-save, ubuntu-data, and ubuntu-boot

func IsRoleMBR 

func IsRoleMBR(ls LaidOutStructure) bool

IsRoleMBR returns whether a structure's role is MBR or not. meh this function is weirdly placed, not sure what to do w/o making schemaMBR constant exported

func KernelCommandLineFromGadget 

func KernelCommandLineFromGadget(gadgetDirOrSnapPath string) (cmdline string, full bool, err error)

KernelCommandLineFromGadget returns the desired kernel command line provided by the gadget. The full flag indicates whether the gadget provides a full command line or just the extra parameters that will be appended to the static ones. An ErrNoKernelCommandline is returned when thea gadget does not set any kernel command line.

func LoadDiskVolumesDeviceTraits 

func LoadDiskVolumesDeviceTraits(dir string) (map[string]DiskVolumeDeviceTraits, error)

LoadDiskVolumesDeviceTraits loads the mapping of volumes to disk traits if there is any. If there is no file with the mapping available, nil is returned.

func MockUpdaterForStructure 

func MockUpdaterForStructure(mock func(loc StructureLocation, ps *LaidOutStructure, rootDir, rollbackDir string, observer ContentUpdateObserver) (Updater, error)) (restore func())

MockUpdaterForStructure replace internal call with a mocked one, for use in tests only

func MockVolumeStructureToLocationMap 

func MockVolumeStructureToLocationMap(f func(_ GadgetData, _ Model, _ map[string]*LaidOutVolume) (map[string]map[int]StructureLocation, error)) (restore func())

func SaveDiskVolumesDeviceTraits 

func SaveDiskVolumesDeviceTraits(dir string, mapping map[string]DiskVolumeDeviceTraits) error

SaveDiskVolumesDeviceTraits saves the mapping of volume names to volume / device traits to a file inside the provided directory on disk for later loading and verification.

func SystemDefaults 

func SystemDefaults(gadgetDefaults map[string]map[string]interface{}) map[string]interface{}

SystemDefaults returns default system configuration from gadget defaults.

func Update 

func Update(model Model, old, new GadgetData, rollbackDirPath string, updatePolicy UpdatePolicyFunc, observer ContentUpdateObserver) error

Update applies the gadget update given the gadget information and data from old and new revisions. It errors out when the update is not possible or illegal, or a failure occurs at any of the steps. When there is no update, a special error ErrNoUpdate is returned.

Only structures selected by the update policy are part of the update. When the policy is nil, a default one is used. The default policy selects structures in an opt-in manner, only tructures with a higher value of Edition field in the new gadget definition are part of the update.

Data that would be modified during the update is first backed up inside the rollback directory. Should the apply step fail, the modified data is recovered.

The rules for gadget/kernel updates with "$kernel:refs":

  1. When installing a kernel with assets that have "update: true" there *must* be a matching entry in gadget.yaml. If not we risk bricking the system because the kernel tells us that it *needs* this file to boot but without gadget.yaml we would not put it anywhere.
  2. When installing a gadget with "$kernel:ref" content it is okay if this content cannot get resolved as long as there is no "edition" jump. This means adding new "$kernel:ref" without "edition" updates is always possible.

To add a new "$kernel:ref" to gadget/kernel: a. Update gadget and gadget.yaml and add "$kernel:ref" but do not 

update edition (if edition update is needed, use epoch)

b. Update kernel and kernel.yaml with new assets. c. snapd will refresh gadget (see rule 2) but refuse to take the 

new kernel (rule 1)

d. After step (c) is completed the kernel refresh will now also 

work (no more violation of rule 1)

func Validate 

func Validate(info *Info, model Model, extra *ValidationConstraints) error

Validate checks that the given gadget metadata matches the consistency rules for role usage, labels etc as implied by the model and extra constraints that might be known only at runtime.

func ValidateContent 

func ValidateContent(info *Info, gadgetSnapRootDir, kernelSnapRootDir string) error

ValidateContent checks whether the given directory contains valid matching content with respect to the given pre-validated gadget metadata.

Types

type Connection 

type Connection struct {
	Plug ConnectionPlug `yaml:"plug"`
	Slot ConnectionSlot `yaml:"slot"`
}

GadgetConnect describes an interface connection requested by the gadget between seeded snaps. The syntax is of a mapping like: 

plug: (<plug-snap-id>|system):plug
[slot: (<slot-snap-id>|system):slot]

"system" indicates a system plug or slot. Fully omitting the slot part indicates a system slot with the same name as the plug.

type ConnectionPlug 

type ConnectionPlug struct {
	SnapID string
	Plug   string
}

func (*ConnectionPlug) Empty 

func (gcplug *ConnectionPlug) Empty() bool

func (*ConnectionPlug) UnmarshalYAML 

func (gcplug *ConnectionPlug) UnmarshalYAML(unmarshal func(interface{}) error) error

type ConnectionSlot 

type ConnectionSlot struct {
	SnapID string
	Slot   string
}

func (*ConnectionSlot) Empty 

func (gcslot *ConnectionSlot) Empty() bool

func (*ConnectionSlot) UnmarshalYAML 

func (gcslot *ConnectionSlot) UnmarshalYAML(unmarshal func(interface{}) error) error

type ContentChange 

type ContentChange struct {
	// Before is a path to a file containing the original data before the
	// operation takes place (or took place in case of ContentRollback).
	Before string
	// After is a path to a file location of the data applied by the operation.
	After string
}

ContentChange carries paths to files containing the content data being modified by the operation.

type ContentChangeAction 

type ContentChangeAction int

type ContentObserver 

type ContentObserver interface {
	// Observe is called to observe an pending or completed action, related
	// to content being written, updated or being rolled back. In each of
	// the scenarios, the target path is relative under the root.
	//
	// For a file write or update, the source path points to the content
	// that will be written. When called during rollback, observe call
	// happens after the original file has been restored (or removed if the
	// file was added during the update), the source path is empty.
	//
	// Returning ChangeApply indicates that the observer agrees for a given
	// change to be applied. When called with a ContentUpdate or
	// ContentWrite operation, returning ChangeIgnore indicates that the
	// change shall be ignored. ChangeAbort is expected to be returned along
	// with a non-nil error.
	Observe(op ContentOperation, sourceStruct *LaidOutStructure,
		targetRootDir, relativeTargetPath string, dataChange *ContentChange) (ContentChangeAction, error)
}

ContentObserver allows for observing operations on the content of the gadget structures.

type ContentOperation 

type ContentOperation int

type ContentUpdateObserver 

type ContentUpdateObserver interface {
	ContentObserver
	// BeforeWrite is called when the backups of content that will get
	// modified during the update are complete and update is ready to be
	// applied.
	BeforeWrite() error
	// Canceled is called when the update has been canceled, or if changes
	// were written and the update has been reverted.
	Canceled() error
}

ContentUpdateObserver allows for observing update (and potentially a rollback) of the gadget structure content.

type DiskEncryptionMethod 

type DiskEncryptionMethod string
const (

	// standard LUKS as it is used for automatic FDE using SecureBoot and TPM
	// 2.0 in UC20+
	EncryptionLUKS DiskEncryptionMethod = "LUKS"
	// ICE stands for Inline Crypto Engine, used on specific (usually embedded)
	// devices
	EncryptionICE DiskEncryptionMethod = "ICE"
)

type DiskStructureDeviceTraits 

type DiskStructureDeviceTraits struct {
	// OriginalDevicePath is the device path in sysfs and in /dev/disk/by-path the
	// partition was measured and observed at during UC20+ install mode.
	OriginalDevicePath string `json:"device-path"`
	// OriginalKernelPath is the device path like /dev/vda1 the partition was
	// measured and observed at during UC20+ install mode.
	OriginalKernelPath string `json:"kernel-path"`
	// PartitionUUID is the partuuid as defined by i.e. /dev/disk/by-partuuid
	PartitionUUID string `json:"partition-uuid"`
	// PartitionLabel is the label of the partition for GPT disks, i.e.
	// /dev/disk/by-partlabel
	PartitionLabel string `json:"partition-label"`
	// PartitionType is the type of the partition i.e. 0x83 for a
	// Linux native partition on DOS, or
	// 0FC63DAF-8483-4772-8E79-3D69D8477DE4 for a Linux filesystem
	// data partition on GPT.
	PartitionType string `json:"partition-type"`
	// FilesystemUUID is the UUID of the filesystem on the partition, i.e.
	// /dev/disk/by-uuid
	FilesystemUUID string `json:"filesystem-uuid"`
	// FilesystemLabel is the label of the filesystem for structures that have
	// filesystems, i.e. /dev/disk/by-label
	FilesystemLabel string `json:"filesystem-label"`
	// FilesystemType is the type of the filesystem, i.e. vfat or ext4, etc.
	FilesystemType string `json:"filesystem-type"`
	// Offset is the offset of the structure
	Offset quantity.Offset `json:"offset"`
	// Size is the size of the structure
	Size quantity.Size `json:"size"`
}

DiskStructureDeviceTraits is a similar to DiskVolumeDeviceTraits, but is a set of traits for a specific structure on a disk rather than the full disk itself. Structures can be full partitions or just raw slices on a disk like the "BIOS Boot" structure on default amd64 grub Ubuntu Core systems.

type DiskVolumeDeviceTraits 

type DiskVolumeDeviceTraits struct {

	// OriginalDevicePath is the device path in sysfs and in /dev/disk/by-path
	// the volume was measured and observed at during UC20+ install mode.
	OriginalDevicePath string `json:"device-path"`

	// OriginalKernelPath is the device path like /dev/vda the volume was
	// measured and observed at during UC20+ install mode.
	OriginalKernelPath string `json:"kernel-path"`

	// DiskID is the disk's identifier, it is a UUID for GPT disks or an
	// unsigned integer for DOS disks encoded as a string in hexadecimal as in
	// "0x1212e868".
	DiskID string `json:"disk-id"`

	// Size is the physical size of the disk, regardless of usable space
	// considerations.
	Size quantity.Size `json:"size"`

	// SectorSize is the physical sector size of the disk, typically 512 or
	// 4096.
	SectorSize quantity.Size `json:"sector-size"`

	// Schema is the disk schema, either dos or gpt in lowercase.
	Schema string `json:"schema"`

	// Structure contains trait information about each individual structure in
	// the volume that may be useful in identifying whether a disk matches a
	// volume or not.
	Structure []DiskStructureDeviceTraits `json:"structure"`

	// StructureEncryption is the set of partitions that are encrypted on the
	// volume - this should only ever have ubuntu-data or ubuntu-save keys for
	// now in the map. The value indicates parameters of the encryption present
	// that enable matching/identifying encrypted structures with their laid out
	// counterparts in the gadget.yaml.
	StructureEncryption map[string]StructureEncryptionParameters `json:"structure-encryption"`
}

DiskVolumeDeviceTraits is a set of traits about a disk that were measured at a previous point in time on the same device, and is used primarily to try and map a volume in the gadget.yaml to a physical device on the system after the initial installation is done. We don't have a steadfast and predictable way to always find the device again, so we need to do a search, trying to find a device which matches each trait in turn, and verify it matches the physical structure layout and if not move on to using the next trait.

func DiskTraitsFromDeviceAndValidate 

func DiskTraitsFromDeviceAndValidate(expLayout *LaidOutVolume, dev string, opts *DiskVolumeValidationOptions) (res DiskVolumeDeviceTraits, err error)

DiskTraitsFromDeviceAndValidate takes a laid out gadget volume and an expected disk device path and confirms that they are compatible, and then builds up the disk volume traits for that device. If the laid out volume is not compatible with the disk structure for the specified device an error is returned.

type DiskVolumeValidationOptions 

type DiskVolumeValidationOptions struct {
	// AllowImplicitSystemData has the same meaning as the eponymously named
	// field in EnsureLayoutCompatibilityOptions.
	AllowImplicitSystemData bool
	// ExpectedEncryptedPartitions is a map of the names (gadget structure
	// names) of partitions that are encrypted on the volume and information
	// about that encryption.
	ExpectedStructureEncryption map[string]StructureEncryptionParameters
}

DiskVolumeValidationOptions is a set of options on how to validate a disk to volume mapping for a specific disk/volume pair. It is closely related to the options provided to EnsureLayoutCompatibility via EnsureLayoutCompatibilityOptions.

type EnsureLayoutCompatibilityOptions 

type EnsureLayoutCompatibilityOptions struct {
	// AssumeCreatablePartitionsCreated will assume that all partitions such as
	// ubuntu-data, ubuntu-save, etc. that are creatable in install mode have
	// already been created and thus must be already exactly matching that which
	// is in the gadget.yaml.
	AssumeCreatablePartitionsCreated bool

	// AllowImplicitSystemData allows the system-data role to be missing from
	// the laid out volume as was allowed in UC18 and UC16 where the system-data
	// partition would be dynamically inserted into the image at image build
	// time by ubuntu-image without being mentioned in the gadget.yaml.
	AllowImplicitSystemData bool

	// ExpectedStructureEncryption is a map of the structure name to information
	// about the encrypted partitions that can be used to validate whether a
	// given structure should be accepted as an encrypted partition.
	ExpectedStructureEncryption map[string]StructureEncryptionParameters
}

EnsureLayoutCompatibilityOptions is a set of options for determining how strict to be when evaluating whether an on-disk structure matches a laid out structure.

type GadgetData 

type GadgetData struct {
	// Info is the gadget metadata
	Info *Info
	// XXX: should be GadgetRootDir
	// RootDir is the root directory of gadget snap data
	RootDir string

	// KernelRootDir is the root directory of kernel snap data
	KernelRootDir string
}

GadgetData holds references to a gadget revision metadata and its data directory.

type Info 

type Info struct {
	Volumes map[string]*Volume `yaml:"volumes,omitempty"`

	// Default configuration for snaps (snap-id => key => value).
	Defaults map[string]map[string]interface{} `yaml:"defaults,omitempty"`

	Connections []Connection `yaml:"connections"`
}

func InfoFromGadgetYaml 

func InfoFromGadgetYaml(gadgetYaml []byte, model Model) (*Info, error)

InfoFromGadgetYaml parses the provided gadget metadata. If model is nil only self-consistency checks are performed. If model is not nil implied values for filesystem labels will be set as well, based on whether the model is for classic, UC16/18 or UC20. UC gadget metadata is expected to have volumes definitions.

func ReadInfo 

func ReadInfo(gadgetSnapRootDir string, model Model) (*Info, error)

ReadInfo reads the gadget specific metadata from meta/gadget.yaml in the snap root directory. See ReadInfoAndValidate for a variant that does role-usage consistency validation like Validate.

func ReadInfoAndValidate 

func ReadInfoAndValidate(gadgetSnapRootDir string, model Model, validationConstraints *ValidationConstraints) (*Info, error)

ReadInfoAndValidate reads the gadget specific metadata from meta/gadget.yaml in the snap root directory. It also performs role-usage consistency validation as Validate does using the given constraints. See ReadInfo for a variant that does not. See also ValidateContent for further validating the content itself instead of the metadata.

func ReadInfoFromSnapFile 

func ReadInfoFromSnapFile(snapf snap.Container, model Model) (*Info, error)

ReadInfoFromSnapFile reads the gadget specific metadata from meta/gadget.yaml in the given snap container. It also performs role-usage consistency validation as Validate does. See ReadInfoFromSnapFileNoValidate for a variant that does not.

func ReadInfoFromSnapFileNoValidate 

func ReadInfoFromSnapFileNoValidate(snapf snap.Container, model Model) (*Info, error)

ReadInfoFromSnapFileNoValidate reads the gadget specific metadata from meta/gadget.yaml in the given snap container. See ReadInfoFromSnapFile for a variant that does role-usage consistency validation like Validate as well.

type LaidOutContent 

type LaidOutContent struct {
	*VolumeContent

	// StartOffset defines the start offset of this content image
	StartOffset quantity.Offset
	// AbsoluteOffsetWrite is the resolved absolute position of offset-write
	// for this content element within the enclosing volume
	AbsoluteOffsetWrite *quantity.Offset
	// Size is the maximum size occupied by this image
	Size quantity.Size
	// Index of the content in structure declaration inside gadget YAML
	Index int
}

LaidOutContent describes raw content that has been placed within the encompassing structure and volume

TODO: this can't have "$kernel:" refs at this point, fail in validate 

for bare structures with "$kernel:" refs

func (LaidOutContent) String 

func (p LaidOutContent) String() string

type LaidOutStructure 

type LaidOutStructure struct {
	*VolumeStructure
	// StartOffset defines the start offset of the structure within the
	// enclosing volume
	StartOffset quantity.Offset
	// AbsoluteOffsetWrite is the resolved absolute position of offset-write
	// for this structure element within the enclosing volume
	AbsoluteOffsetWrite *quantity.Offset
	// Index of the structure definition in gadget YAML, note this starts at 0.
	YamlIndex int
	// LaidOutContent is a list of raw content inside the structure
	LaidOutContent []LaidOutContent
	// ResolvedContent is a list of filesystem content that has all
	// relative paths or references resolved
	ResolvedContent []ResolvedContent
}

LaidOutStructure describes a VolumeStructure that has been placed within the volume

func ShiftStructureTo 

func ShiftStructureTo(ps LaidOutStructure, offset quantity.Offset) LaidOutStructure

ShiftStructureTo translates the starting offset of a laid out structure and its content to the provided offset.

func (LaidOutStructure) String 

func (p LaidOutStructure) String() string

type LaidOutVolume 

type LaidOutVolume struct {
	*Volume
	// Size is the total size of the volume
	Size quantity.Size
	// LaidOutStructure is a list of structures within the volume, sorted
	// by their start offsets
	LaidOutStructure []LaidOutStructure
	// RootDir is the root directory for volume data
	RootDir string
}

LaidOutVolume defines the size of a volume and arrangement of all the structures within it

func LaidOutVolumesFromGadget 

func LaidOutVolumesFromGadget(gadgetRoot, kernelRoot string, model Model) (system *LaidOutVolume, all map[string]*LaidOutVolume, err error)

LaidOutVolumesFromGadget takes a gadget rootdir and lays out the partitions on all volumes as specified. It returns the specific volume on which system-* roles/partitions exist, as well as all volumes mentioned in the gadget.yaml and their laid out representations. Those volumes are assumed to already be flashed and managed separately at image build/flash time, while the system volume with all the system-* roles on it can be manipulated during install mode.

func LayoutVolume 

func LayoutVolume(volume *Volume, constraints LayoutConstraints, opts *LayoutOptions) (*LaidOutVolume, error)

LayoutVolume attempts to completely lay out the volume, that is the structures and their content, using provided constraints

type LayoutConstraints 

type LayoutConstraints struct {
	// NonMBRStartOffset is the default start offset of non-MBR structure in
	// the volume.
	NonMBRStartOffset quantity.Offset
}

LayoutConstraints defines the constraints for arranging structures within a volume

type LayoutOptions 

type LayoutOptions struct {
	// SkipResolveContent will skip resolving content paths
	// and `$kernel:` style references
	SkipResolveContent bool

	// IgnoreContent will skip laying out content structure data to the
	// volume. Settings this implies "SkipResolveContent".  This
	// is used when only the partitions need to get
	// created and content gets written later.
	IgnoreContent bool

	GadgetRootDir string
	KernelRootDir string
}

LayoutOptions defines the options to layout a given volume.

type Model 

type Model interface {
	Classic() bool
	Grade() asserts.ModelGrade
}

Model carries characteristics about the model that are relevant to gadget. Note *asserts.Model implements this, and that's the expected use case.

type MountedFilesystemWriter 

type MountedFilesystemWriter struct {
	// contains filtered or unexported fields
}

MountedFilesystemWriter assists in writing contents of a structure to a mounted filesystem.

func NewMountedFilesystemWriter 

func NewMountedFilesystemWriter(ps *LaidOutStructure, observer ContentObserver) (*MountedFilesystemWriter, error)

NewMountedFilesystemWriter returns a writer capable of writing provided structure, with content of the structure stored in the given root directory.

func (*MountedFilesystemWriter) Write 

func (m *MountedFilesystemWriter) Write(whereDir string, preserve []string) error

Write writes structure data into provided directory. All existing files are overwritten, unless their paths, relative to target directory, are listed in the preserve list. Permission bits and ownership of updated entries is not preserved.

type OnDiskStructure 

type OnDiskStructure struct {
	LaidOutStructure

	// Node identifies the device node of the block device.
	Node string

	// DiskIndex is the index of the structure on the disk - this should be
	// used instead of YamlIndex for an OnDiskStructure, YamlIndex comes from
	// the embedded LaidOutStructure which is 0-based and does not have the same
	// meaning. A LaidOutStructure's YamlIndex position will include that of
	// bare structures which will not show up as an OnDiskStructure, so the
	// range of OnDiskStructure.DiskIndex values is not necessarily the same as
	// the range of LaidOutStructure.YamlIndex values.
	DiskIndex int

	// Size of the on disk structure, which is at least equal to the
	// LaidOutStructure.Size but may be bigger if the partition was
	// expanded.
	Size quantity.Size
}

OnDiskStructure represents a gadget structure laid on a block device.

func OnDiskStructureFromPartition 

func OnDiskStructureFromPartition(p disks.Partition) (OnDiskStructure, error)

type OnDiskVolume 

type OnDiskVolume struct {
	Structure []OnDiskStructure
	// ID is the disk's identifier, it is a UUID for GPT disks or an unsigned
	// integer for DOS disks encoded as a string in hexadecimal as in
	// "0x1212e868".
	ID string
	// Device is the full device node path for the disk, such as /dev/vda.
	Device string
	// Schema is the disk schema, GPT or DOS.
	Schema string
	// size in bytes
	Size quantity.Size
	// UsableSectorsEnd is the end (exclusive) of usable sectors on the disk,
	// this sector specifically is not usable for partitions, though it may be
	// used for i.e. GPT header backups on some disks. This should be used when
	// calculating the size of an auto-expanded partition instead of the Size
	// parameter which does not take this into account.
	UsableSectorsEnd uint64
	// sector size in bytes
	SectorSize quantity.Size
}

OnDiskVolume holds information about the disk device including its partitioning schema, the partition table, and the structure layout it contains.

func OnDiskVolumeFromDevice 

func OnDiskVolumeFromDevice(device string) (*OnDiskVolume, error)

OnDiskVolumeFromDevice obtains the partitioning and filesystem information from the block device.

func OnDiskVolumeFromDisk 

func OnDiskVolumeFromDisk(disk disks.Disk) (*OnDiskVolume, error)

type PartiallyLaidOutVolume 

type PartiallyLaidOutVolume struct {
	*Volume
	// LaidOutStructure is a list of structures within the volume, sorted
	// by their start offsets
	LaidOutStructure []LaidOutStructure
}

PartiallyLaidOutVolume defines the layout of volume structures, but lacks the details about the layout of raw image content within the bare structures.

func LayoutVolumePartially 

func LayoutVolumePartially(volume *Volume, constraints LayoutConstraints) (*PartiallyLaidOutVolume, error)

LayoutVolumePartially attempts to lay out only the structures in the volume using provided constraints

type RawStructureWriter 

type RawStructureWriter struct {
	// contains filtered or unexported fields
}

RawStructureWriter implements support for writing raw (bare) structures.

func NewRawStructureWriter 

func NewRawStructureWriter(contentDir string, ps *LaidOutStructure) (*RawStructureWriter, error)

NewRawStructureWriter returns a writer for the given structure, that will load the structure content data from the provided gadget content directory.

func (*RawStructureWriter) Write 

func (r *RawStructureWriter) Write(out io.WriteSeeker) error

Write will write whole contents of a structure into the output stream.

type RelativeOffset 

type RelativeOffset struct {
	// RelativeTo names the structure relative to which the location of the
	// address write will be calculated.
	RelativeTo string `yaml:"relative-to" json:"relative-to"`
	// Offset is a 32-bit value
	Offset quantity.Offset `yaml:"offset" json:"offset"`
}

RelativeOffset describes an offset where structure data is written at. The position can be specified as byte-offset relative to the start of another named structure.

func (*RelativeOffset) String 

func (r *RelativeOffset) String() string

func (*RelativeOffset) UnmarshalYAML 

func (s *RelativeOffset) UnmarshalYAML(unmarshal func(interface{}) error) error

type ResolvedContent 

type ResolvedContent struct {
	*VolumeContent

	// ResolvedSource is the absolute path of the Source after resolving
	// any references (e.g. to a "$kernel:" snap).
	ResolvedSource string

	// KernelUpdate is true if this content comes from the kernel
	// and has the "Update" property set
	KernelUpdate bool
}

type ResolvedContentFilterFunc 

type ResolvedContentFilterFunc func(*ResolvedContent) bool

ResolvedContentFilterFunc is a callback that evaluates the given ResolvedContent and returns true if it should be applied as part of an update. This is relevant for e.g. asset updates that come from the kernel snap.

func KernelUpdatePolicy 

func KernelUpdatePolicy(from, to *LaidOutStructure) (bool, ResolvedContentFilterFunc)

KernelUpdatePolicy implements the update policy for kernel asset updates.

This is called when there is a kernel->kernel refresh for kernels that contain bootloader assets. In this case all bootloader assets that are marked as "update: true" in the kernel.yaml need updating.

But any non-kernel assets need to be ignored, they will be handled by the regular gadget->gadget update mechanism and policy.

func RemodelUpdatePolicy 

func RemodelUpdatePolicy(from, to *LaidOutStructure) (bool, ResolvedContentFilterFunc)

RemodelUpdatePolicy implements the update policy of a remodel scenario. The policy selects all non-MBR structures for the update.

type StructureEncryptionParameters 

type StructureEncryptionParameters struct {
	// Method is the method of encryption used, currently only EncryptionLUKS is
	// recognized.
	Method DiskEncryptionMethod `json:"method"`
	// contains filtered or unexported fields
}

StructureEncryptionParameters contains information about an encrypted structure, used to match encrypted structures on disk with their abstract, laid out counterparts in the gadget.yaml.

func (*StructureEncryptionParameters) UnmarshalJSON 

func (s *StructureEncryptionParameters) UnmarshalJSON(b []byte) error

type StructureLocation 

type StructureLocation struct {
	// Device is the kernel device node path such as /dev/vda1 for the
	// structure's backing physical disk.
	Device string
	// Offset is the offset from 0 for the physical disk that this structure
	// starts at.
	Offset quantity.Offset

	// RootMountPoint is the directory where the root directory of the structure
	// is mounted read/write. There may be other mount points for this structure
	// on the system, but this one is guaranteed to be writable and thus
	// suitable for gadget asset updates.
	RootMountPoint string
}

StructureLocation represents the location of a structure for updating purposes. Either Device + Offset must be set for a raw structure without a filesystem, or RootMountPoint must be set for structures with a filesystem.

type UpdatePolicyFunc 

type UpdatePolicyFunc func(from, to *LaidOutStructure) (bool, ResolvedContentFilterFunc)

UpdatePolicyFunc is a callback that evaluates the provided pair of (potentially not yet resolved) structures and returns true when the pair should be part of an update. It may also return a filter function for the resolved content when not all of the content should be applied as part of the update (e.g. when updating assets from the kernel snap).

type Updater 

type Updater interface {
	// Update applies the update or errors out on failures. When no actual
	// update was applied because the new content is identical a special
	// ErrNoUpdate is returned.
	Update() error
	// Backup prepares a backup copy of data that will be modified by
	// Update()
	Backup() error
	// Rollback restores data modified by update
	Rollback() error
}

type ValidationConstraints 

type ValidationConstraints struct {
	// EncryptedData when true indicates that the gadget will be used on a
	// device where the data partition will be encrypted.
	EncryptedData bool
}

ValidationConstraints carries extra constraints on top of those implied by the model to use for gadget validation. They might be constraints that are determined only at runtime.

type Volume 

type Volume struct {
	// Schema describes the schema used for the volume
	Schema string `yaml:"schema" json:"schema"`
	// Bootloader names the bootloader used by the volume
	Bootloader string `yaml:"bootloader" json:"bootloader"`
	//  ID is a 2-hex digit disk ID or GPT GUID
	ID string `yaml:"id" json:"id"`
	// Structure describes the structures that are part of the volume
	Structure []VolumeStructure `yaml:"structure" json:"structure"`
	// Name is the name of the volume from the gadget.yaml
	Name string `json:"-"`
}

Volume defines the structure and content for the image to be written into a block device.

type VolumeContent 

type VolumeContent struct {
	// UnresovedSource is the data of the partition relative to
	// the gadget base directory
	UnresolvedSource string `yaml:"source" json:"source"`
	// Target is the location of the data inside the root filesystem
	Target string `yaml:"target" json:"target"`

	// Image names the image, relative to gadget base directory, to be used
	// for a 'bare' type structure
	Image string `yaml:"image" json:"image"`
	// Offset the image is written at
	Offset *quantity.Offset `yaml:"offset" json:"offset"`
	// OffsetWrite describes a 32-bit address, within the volume, at which
	// the offset of current image will be written. The position may be
	// specified as a byte offset relative to the start of a named structure
	OffsetWrite *RelativeOffset `yaml:"offset-write" json:"offset-write"`
	// Size of the image, when empty size is calculated by looking at the
	// image
	Size quantity.Size `yaml:"size" json:"size"`

	Unpack bool `yaml:"unpack" json:"unpack"`
}

VolumeContent defines the contents of the structure. The content can be either files within a filesystem described by the structure or raw images written into the area of a bare structure.

func (VolumeContent) String 

func (vc VolumeContent) String() string

type VolumeStructure 

type VolumeStructure struct {
	// VolumeName is the name of the volume that this structure belongs to.
	VolumeName string `json:"-"`
	// Name, when non empty, provides the name of the structure
	Name string `yaml:"name" json:"name"`
	// Label provides the filesystem label
	Label string `yaml:"filesystem-label" json:"filesystem-label"`
	// Offset defines a starting offset of the structure
	Offset *quantity.Offset `yaml:"offset" json:"offset"`
	// OffsetWrite describes a 32-bit address, within the volume, at which
	// the offset of current structure will be written. The position may be
	// specified as a byte offset relative to the start of a named structure
	OffsetWrite *RelativeOffset `yaml:"offset-write" json:"offset-write"`
	// Size of the structure
	Size quantity.Size `yaml:"size" json:"size"`
	// Type of the structure, which can be 2-hex digit MBR partition,
	// 36-char GUID partition, comma separated <mbr>,<guid> for hybrid
	// partitioning schemes, or 'bare' when the structure is not considered
	// a partition.
	//
	// For backwards compatibility type 'mbr' is also accepted, and the
	// structure is treated as if it is of role 'mbr'.
	Type string `yaml:"type" json:"type"`
	// Role describes the role of given structure, can be one of
	// 'mbr', 'system-data', 'system-boot', 'system-boot-image',
	// 'system-boot-select' or 'system-recovery-select'. Structures of type 'mbr', must have a
	// size of 446 bytes and must start at 0 offset.
	Role string `yaml:"role" json:"role"`
	// ID is the GPT partition ID, this should always be made upper case for
	// comparison purposes.
	ID string `yaml:"id" json:"id"`
	// Filesystem used for the partition, 'vfat', 'ext4' or 'none' for
	// structures of type 'bare'
	Filesystem string `yaml:"filesystem" json:"filesystem"`
	// Content of the structure
	Content []VolumeContent `yaml:"content" json:"content"`
	Update  VolumeUpdate    `yaml:"update" json:"update"`

	// Note that the Device field will never be part of the yaml
	// and just used as part of the POST /systems/<label> API that
	// is used by an installer.
	Device string `yaml:"-" json:"device,omitempty"`
}

VolumeStructure describes a single structure inside a volume. A structure can represent a partition, Master Boot Record, or any other contiguous range within the volume.

func (*VolumeStructure) HasFilesystem 

func (vs *VolumeStructure) HasFilesystem() bool

HasFilesystem returns true if the structure is using a filesystem.

func (*VolumeStructure) IsPartition 

func (vs *VolumeStructure) IsPartition() bool

IsPartition returns true when the structure describes a partition in a block device.

type VolumeUpdate 

type VolumeUpdate struct {
	Edition  edition.Number `yaml:"edition" json:"edition"`
	Preserve []string       `yaml:"preserve" json:"preserve"`
}

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