mount

Documentation

Overview

Package mount defines an interface to mounting filesystems.

Index

• Constants
• func AddSystemdScope(systemdRunPath, mountName, command string, args []string) (string, []string)
• func CleanupMountPoint(mountPath string, mounter Interface, extensiveMountPointCheck bool) error
• func GetDeviceNameFromMount(mounter Interface, mountPath string) (string, int, error)
• func IsCorruptedMnt(err error) bool
• func IsNotMountPoint(mounter Interface, file string) (bool, error)
• func MakeBindOpts(options []string) (bool, []string, []string)
• func MakeMountArgs(source, target, fstype string, options []string) []string
• func PathExists(path string) (bool, error)
• func PathWithinBase(fullPath, basePath string) bool
• func SearchMountPoints(hostSource, mountInfoPath string) ([]string, error)
• func StartsWithBackstep(rel string) bool
• type Exec
  • func NewOSExec() Exec
• type FakeAction
• type FakeExec
  • func NewFakeExec(run runHook) *FakeExec
  • func (f *FakeExec) Run(cmd string, args ...string) ([]byte, error)
• type FakeMounter
  • func (f *FakeMounter) GetMountRefs(pathname string) ([]string, error)
  • func (f *FakeMounter) IsLikelyNotMountPoint(file string) (bool, error)
  • func (f *FakeMounter) List() ([]MountPoint, error)
  • func (f *FakeMounter) Mount(source string, target string, fstype string, options []string) error
  • func (f *FakeMounter) ResetLog()
  • func (f *FakeMounter) Unmount(target string) error
• type Interface
  • func New(mounterPath string) Interface
• type MountInfo
  • func ParseMountInfo(filename string) ([]MountInfo, error)
• type MountPoint
  • func ListProcMounts(mountFilePath string) ([]MountPoint, error)
• type Mounter
  • func (mounter *Mounter) GetMountRefs(pathname string) ([]string, error)
  • func (mounter *Mounter) IsLikelyNotMountPoint(file string) (bool, error)
  • func (*Mounter) List() ([]MountPoint, error)
  • func (mounter *Mounter) Mount(source string, target string, fstype string, options []string) error
  • func (mounter *Mounter) Unmount(target string) error
• type SafeFormatAndMount
  • func (mounter *SafeFormatAndMount) FormatAndMount(source string, target string, fstype string, options []string) error
  • func (mounter *SafeFormatAndMount) GetDiskFormat(disk string) (string, error)

Constants

const (
	// FakeActionMount is the string for specifying mount as FakeAction.Action
	FakeActionMount = "mount"
	// FakeActionUnmount is the string for specifying unmount as FakeAction.Action
	FakeActionUnmount = "unmount"
)

Functions

func AddSystemdScope

func AddSystemdScope(systemdRunPath, mountName, command string, args []string) (string, []string)

AddSystemdScope adds "system-run --scope" to given command line implementation is shared with NsEnterMounter

func CleanupMountPoint

func CleanupMountPoint(mountPath string, mounter Interface, extensiveMountPointCheck bool) error

CleanupMountPoint unmounts the given path and deletes the remaining directory if successful. If extensiveMountPointCheck is true IsNotMountPoint will be called instead of IsLikelyNotMountPoint. IsNotMountPoint is more expensive but properly handles bind mounts within the same fs.

func GetDeviceNameFromMount

func GetDeviceNameFromMount(mounter Interface, mountPath string) (string, int, error)

GetDeviceNameFromMount given a mnt point, find the device from /proc/mounts returns the device name, reference count, and error code.

func IsCorruptedMnt

func IsCorruptedMnt(err error) bool

IsCorruptedMnt return true if err is about corrupted mount point

func IsNotMountPoint

func IsNotMountPoint(mounter Interface, file string) (bool, error)

IsNotMountPoint determines if a directory is a mountpoint. It should return ErrNotExist when the directory does not exist. IsNotMountPoint is more expensive than IsLikelyNotMountPoint. IsNotMountPoint detects bind mounts in linux. IsNotMountPoint enumerates all the mountpoints using List() and the list of mountpoints may be large, then it uses isMountPointMatch to evaluate whether the directory is a mountpoint.

func MakeBindOpts

func MakeBindOpts(options []string) (bool, []string, []string)

MakeBindOpts detects whether a bind mount is being requested and makes the remount options to use in case of bind mount, due to the fact that bind mount doesn't respect mount options. The list equals:

options - 'bind' + 'remount' (no duplicate)

func MakeMountArgs

func MakeMountArgs(source, target, fstype string, options []string) []string

MakeMountArgs makes the arguments to the mount(8) command. Implementation is shared with NsEnterMounter

func PathExists

func PathExists(path string) (bool, error)

PathExists returns true if the specified path exists. TODO: clean this up to use pkg/util/file/FileExists

func PathWithinBase

func PathWithinBase(fullPath, basePath string) bool

PathWithinBase checks if give path is within given base directory.

func SearchMountPoints

func SearchMountPoints(hostSource, mountInfoPath string) ([]string, error)

SearchMountPoints finds all mount references to the source, returns a list of mountpoints. This function assumes source cannot be device. Some filesystems may share a source name, e.g. tmpfs. And for bind mounting, it's possible to mount a non-root path of a filesystem, so we need to use root path and major:minor to represent mount source uniquely. This implementation is shared between Linux and NsEnterMounter

func StartsWithBackstep

func StartsWithBackstep(rel string) bool

StartsWithBackstep checks if the given path starts with a backstep segment.

Types

type Exec

type Exec interface {
	// Run executes a command and returns its stdout + stderr combined in one
	// stream.
	Run(cmd string, args ...string) ([]byte, error)
}

Exec is an interface for executing commands on systems.

func NewOSExec

func NewOSExec() Exec

NewOSExec returns a new Exec interface implementation based on exec()

type FakeAction

type FakeAction struct {
	Action string // "mount" or "unmount"
	Target string // applies to both mount and unmount actions
	Source string // applies only to "mount" actions
	FSType string // applies only to "mount" actions
}

FakeAction objects are logged every time a fake mount or unmount is called.

type FakeExec

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

FakeExec for testing.

func NewFakeExec

func NewFakeExec(run runHook) *FakeExec

NewFakeExec returns a new FakeExec

func (*FakeExec) Run

func (f *FakeExec) Run(cmd string, args ...string) ([]byte, error)

Run executes the command using the optional runhook, if given

type FakeMounter

type FakeMounter struct {
	MountPoints []MountPoint
	Log         []FakeAction
	// Error to return for a path when calling IsLikelyNotMountPoint
	MountCheckErrors map[string]error
	// contains filtered or unexported fields
}

FakeMounter implements mount.Interface for tests.

func (*FakeMounter) GetMountRefs

func (f *FakeMounter) GetMountRefs(pathname string) ([]string, error)

GetMountRefs finds all mount references to the path, returns a list of paths.

func (*FakeMounter) IsLikelyNotMountPoint

func (f *FakeMounter) IsLikelyNotMountPoint(file string) (bool, error)

IsLikelyNotMountPoint determines whether a path is a mountpoint by checking if the absolute path to file is in the in-memory mountpoints

func (*FakeMounter) List

func (f *FakeMounter) List() ([]MountPoint, error)

List returns all the in-memory mountpoints for FakeMounter

func (*FakeMounter) Mount

func (f *FakeMounter) Mount(source string, target string, fstype string, options []string) error

Mount records the mount event and updates the in-memory mount points for FakeMounter

func (*FakeMounter) ResetLog

func (f *FakeMounter) ResetLog()

ResetLog clears all the log entries in FakeMounter

func (*FakeMounter) Unmount

func (f *FakeMounter) Unmount(target string) error

Unmount records the unmount event and updates the in-memory mount points for FakeMounter

type Interface

type Interface interface {
	// Mount mounts source to target as fstype with given options.
	Mount(source string, target string, fstype string, options []string) error
	// Unmount unmounts given target.
	Unmount(target string) error
	// List returns a list of all mounted filesystems.  This can be large.
	// On some platforms, reading mounts directly from the OS is not guaranteed
	// consistent (i.e. it could change between chunked reads). This is guaranteed
	// to be consistent.
	List() ([]MountPoint, error)
	// IsLikelyNotMountPoint uses heuristics to determine if a directory
	// is not a mountpoint.
	// It should return ErrNotExist when the directory does not exist.
	// IsLikelyNotMountPoint does NOT properly detect all mountpoint types
	// most notably linux bind mounts and symbolic link.
	IsLikelyNotMountPoint(file string) (bool, error)
	// GetMountRefs finds all mount references to the path, returns a
	// list of paths. Path could be a mountpoint path, device or a normal
	// directory (for bind mount).
	GetMountRefs(pathname string) ([]string, error)
}

Interface defines the set of methods to allow for mount operations on a system.

func New

func New(mounterPath string) Interface

New returns a mount.Interface for the current system. It provides options to override the default mounter behavior. mounterPath allows using an alternative to `/bin/mount` for mounting.

type MountInfo

type MountInfo struct {
	// Unique ID for the mount (maybe reused after umount).
	ID int
	// The ID of the parent mount (or of self for the root of this mount namespace's mount tree).
	ParentID int
	// The value of `st_dev` for files on this filesystem.
	MajorMinor string
	// The pathname of the directory in the filesystem which forms the root of this mount.
	Root string
	// Mount source, filesystem-specific information. e.g. device, tmpfs name.
	Source string
	// Mount point, the pathname of the mount point.
	MountPoint string
	// Optional fieds, zero or more fields of the form "tag[:value]".
	OptionalFields []string
	// The filesystem type in the form "type[.subtype]".
	FsType string
	// Per-mount options.
	MountOptions []string
	// Per-superblock options.
	SuperOptions []string
}

MountInfo represents a single line in /proc/<pid>/mountinfo.

func ParseMountInfo

func ParseMountInfo(filename string) ([]MountInfo, error)

ParseMountInfo parses /proc/xxx/mountinfo.

type MountPoint

type MountPoint struct {
	Device string
	Path   string
	Type   string
	Opts   []string
	Freq   int
	Pass   int
}

MountPoint represents a single line in /proc/mounts or /etc/fstab.

func ListProcMounts

func ListProcMounts(mountFilePath string) ([]MountPoint, error)

ListProcMounts is shared with NsEnterMounter

type Mounter

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

Mounter provides the default implementation of mount.Interface for the linux platform. This implementation assumes that the kubelet is running in the host's root mount namespace.

func (*Mounter) GetMountRefs

func (mounter *Mounter) GetMountRefs(pathname string) ([]string, error)

GetMountRefs finds all mount references to pathname, returns a list of paths. Path could be a mountpoint path, device or a normal directory (for bind mount).

func (*Mounter) IsLikelyNotMountPoint

func (mounter *Mounter) IsLikelyNotMountPoint(file string) (bool, error)

IsLikelyNotMountPoint determines if a directory is not a mountpoint. It is fast but not necessarily ALWAYS correct. If the path is in fact a bind mount from one part of a mount to another it will not be detected. It also can not distinguish between mountpoints and symbolic links. mkdir /tmp/a /tmp/b; mount --bind /tmp/a /tmp/b; IsLikelyNotMountPoint("/tmp/b") will return true. When in fact /tmp/b is a mount point. If this situation is of interest to you, don't use this function...

func (*Mounter) List

func (*Mounter) List() ([]MountPoint, error)

List returns a list of all mounted filesystems.

func (*Mounter) Mount

func (mounter *Mounter) Mount(source string, target string, fstype string, options []string) error

Mount mounts source to target as fstype with given options. 'source' and 'fstype' must be an empty string in case it's not required, e.g. for remount, or for auto filesystem type, where kernel handles fstype for you. The mount 'options' is a list of options, currently come from mount(8), e.g. "ro", "remount", "bind", etc. If no more option is required, call Mount with an empty string list or nil.

func (*Mounter) Unmount

func (mounter *Mounter) Unmount(target string) error

Unmount unmounts the target.

type SafeFormatAndMount

type SafeFormatAndMount struct {
	Interface
	Exec
}

SafeFormatAndMount probes a device to see if it is formatted. Namely it checks to see if a file system is present. If so it mounts it otherwise the device is formatted first then mounted.

func (*SafeFormatAndMount) FormatAndMount

func (mounter *SafeFormatAndMount) FormatAndMount(source string, target string, fstype string, options []string) error

FormatAndMount formats the given disk, if needed, and mounts it. That is if the disk is not formatted and it is not being mounted as read-only it will format it first then mount it. Otherwise, if the disk is already formatted or it is being mounted as read-only, it will be mounted without formatting.

func (*SafeFormatAndMount) GetDiskFormat

func (mounter *SafeFormatAndMount) GetDiskFormat(disk string) (string, error)

GetDiskFormat uses 'blkid' to see if the given disk is unformatted