mount

Documentation

Overview

TODO(thockin): This whole pkg is pretty linux-centric. As soon as we have an alternate platform, we will need to abstract further.

Index

• func GetDeviceNameFromMount(mounter Interface, mountPath string) (string, int, error)
• func HasMountRefs(mountPath string, mountRefs []string) bool
• func IsNotMountPoint(mounter Interface, file string) (bool, error)
• func PathWithinBase(fullPath, basePath string) bool
• type Exec
• type FileType
• type Interface
  • func New(mounterPath string) Interface
• type MountPoint
• type Mounter
  • func (mounter *Mounter) CleanSubPaths(podDir string, volumeName string) error
  • func (mounter *Mounter) DeviceOpened(pathname string) (bool, error)
  • func (mounter *Mounter) EvalHostSymlinks(pathname string) (string, error)
  • func (mounter *Mounter) ExistsPath(pathname string) (bool, error)
  • func (mounter *Mounter) GetDeviceNameFromMount(mountPath, pluginDir string) (string, error)
  • func (mounter *Mounter) GetFSGroup(pathname string) (int64, error)
  • func (mounter *Mounter) GetFileType(pathname string) (FileType, error)
  • func (mounter *Mounter) GetMode(pathname string) (os.FileMode, error)
  • func (mounter *Mounter) GetMountRefs(pathname string) ([]string, error)
  • func (mounter *Mounter) GetSELinuxSupport(pathname string) (bool, error)
  • func (mounter *Mounter) IsLikelyNotMountPoint(file string) (bool, error)
  • func (mounter *Mounter) IsMountPointMatch(mp MountPoint, dir string) bool
  • func (mounter *Mounter) IsNotMountPoint(dir string) (bool, error)
  • func (*Mounter) List() ([]MountPoint, error)
  • func (mounter *Mounter) MakeDir(pathname string) error
  • func (mounter *Mounter) MakeFile(pathname string) error
  • func (mounter *Mounter) MakeRShared(path string) error
  • func (mounter *Mounter) Mount(source string, target string, fstype string, options []string) error
  • func (mounter *Mounter) PathIsDevice(pathname string) (bool, error)
  • func (mounter *Mounter) PrepareSafeSubpath(subPath Subpath) (newHostPath string, cleanupAction func(), err error)
  • func (mounter *Mounter) SafeMakeDir(subdir string, base string, perm os.FileMode) 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)
• type Subpath

Functions

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 HasMountRefs

func HasMountRefs(mountPath string, mountRefs []string) bool

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. This method uses the List() of all mountpoints It is more extensive than IsLikelyNotMountPoint and it detects bind mounts in linux

func PathWithinBase

func PathWithinBase(fullPath, basePath string) bool

PathWithinBase checks if give path is within given base directory.

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 executes command where mount utilities are. This can be either the host, container where kubelet runs or even a remote pod with mount utilities. Usual pkg/util/exec interface is not used because kubelet.RunInContainer does not provide stdin/stdout/stderr streams.

type FileType

type FileType string

const (
	MountsInGlobalPDPath          = "mounts"
	FileTypeDirectory    FileType = "Directory"
	FileTypeFile         FileType = "File"
	FileTypeSocket       FileType = "Socket"
	FileTypeCharDev      FileType = "CharDevice"
	FileTypeBlockDev     FileType = "BlockDevice"
)

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 is not guaranteed consistent (i.e.
	// it could change between chunked reads). This is guaranteed to be
	// consistent.
	List() ([]MountPoint, error)
	// IsMountPointMatch determines if the mountpoint matches the dir
	IsMountPointMatch(mp MountPoint, dir string) bool
	// 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
	IsNotMountPoint(file string) (bool, error)
	// IsLikelyNotMountPoint uses heuristics to determine if a directory
	// is 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.
	IsLikelyNotMountPoint(file string) (bool, error)
	// DeviceOpened determines if the device is in use elsewhere
	// on the system, i.e. still mounted.
	DeviceOpened(pathname string) (bool, error)
	// PathIsDevice determines if a path is a device.
	PathIsDevice(pathname string) (bool, error)
	// GetDeviceNameFromMount finds the device name by checking the mount path
	// to get the global mount path which matches its plugin directory
	GetDeviceNameFromMount(mountPath, pluginDir string) (string, error)
	// MakeRShared checks that given path is on a mount with 'rshared' mount
	// propagation. If not, it bind-mounts the path as rshared.
	MakeRShared(path string) error
	// GetFileType checks for file/directory/socket/block/character devices.
	// Will operate in the host mount namespace if kubelet is running in a container
	GetFileType(pathname string) (FileType, error)
	// MakeFile creates an empty file.
	// Will operate in the host mount namespace if kubelet is running in a container
	MakeFile(pathname string) error
	// MakeDir creates a new directory.
	// Will operate in the host mount namespace if kubelet is running in a container
	MakeDir(pathname string) error
	// SafeMakeDir creates subdir within given base. It makes sure that the
	// created directory does not escape given base directory mis-using
	// symlinks. Note that the function makes sure that it creates the directory
	// somewhere under the base, nothing else. E.g. if the directory already
	// exists, it may exist outside of the base due to symlinks.
	// This method should be used if the directory to create is inside volume
	// that's under user control. User must not be able to use symlinks to
	// escape the volume to create directories somewhere else.
	SafeMakeDir(subdir string, base string, perm os.FileMode) error
	// Will operate in the host mount namespace if kubelet is running in a container.
	// Error is returned on any other error than "file not found".
	ExistsPath(pathname string) (bool, error)
	// EvalHostSymlinks returns the path name after evaluating symlinks.
	// Will operate in the host mount namespace if kubelet is running in a container.
	EvalHostSymlinks(pathname string) (string, error)
	// CleanSubPaths removes any bind-mounts created by PrepareSafeSubpath in given
	// pod volume directory.
	CleanSubPaths(podDir string, volumeName string) error
	// PrepareSafeSubpath does everything that's necessary to prepare a subPath
	// that's 1) inside given volumePath and 2) immutable after this call.
	//
	// newHostPath - location of prepared subPath. It should be used instead of
	// hostName when running the container.
	// cleanupAction - action to run when the container is running or it failed to start.
	//
	// CleanupAction must be called immediately after the container with given
	// subpath starts. On the other hand, Interface.CleanSubPaths must be called
	// when the pod finishes.
	PrepareSafeSubpath(subPath Subpath) (newHostPath string, cleanupAction func(), err 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)
	// GetFSGroup returns FSGroup of the path.
	GetFSGroup(pathname string) (int64, error)
	// GetSELinuxSupport returns true if given path is on a mount that supports
	// SELinux.
	GetSELinuxSupport(pathname string) (bool, error)
	// GetMode returns permissions of the path.
	GetMode(pathname string) (os.FileMode, error)
}

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 MountPoint

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

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

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) CleanSubPaths

func (mounter *Mounter) CleanSubPaths(podDir string, volumeName string) error

func (*Mounter) DeviceOpened

func (mounter *Mounter) DeviceOpened(pathname string) (bool, error)

DeviceOpened checks if block device in use by calling Open with O_EXCL flag. If pathname is not a device, log and return false with nil error. If open returns errno EBUSY, return true with nil error. If open returns nil, return false with nil error. Otherwise, return false with error

func (*Mounter) EvalHostSymlinks

func (mounter *Mounter) EvalHostSymlinks(pathname string) (string, error)

func (*Mounter) ExistsPath

func (mounter *Mounter) ExistsPath(pathname string) (bool, error)

func (*Mounter) GetDeviceNameFromMount

func (mounter *Mounter) GetDeviceNameFromMount(mountPath, pluginDir string) (string, error)

GetDeviceNameFromMount: given a mount point, find the device name from its global mount point

func (*Mounter) GetFSGroup

func (mounter *Mounter) GetFSGroup(pathname string) (int64, error)

func (*Mounter) GetFileType

func (mounter *Mounter) GetFileType(pathname string) (FileType, error)

func (*Mounter) GetMode

func (mounter *Mounter) GetMode(pathname string) (os.FileMode, error)

func (*Mounter) GetMountRefs

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

func (*Mounter) GetSELinuxSupport

func (mounter *Mounter) GetSELinuxSupport(pathname string) (bool, error)

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. mkdir /tmp/a /tmp/b; mount --bin /tmp/a /tmp/b; IsLikelyNotMountPoint("/tmp/b") will return true. When in fact /tmp/b is a mount point. If this situation if of interest to you, don't use this function...

func (*Mounter) IsMountPointMatch

func (mounter *Mounter) IsMountPointMatch(mp MountPoint, dir string) bool

func (*Mounter) IsNotMountPoint

func (mounter *Mounter) IsNotMountPoint(dir string) (bool, error)

func (*Mounter) List

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

List returns a list of all mounted filesystems.

func (*Mounter) MakeDir

func (mounter *Mounter) MakeDir(pathname string) error

func (*Mounter) MakeFile

func (mounter *Mounter) MakeFile(pathname string) error

func (*Mounter) MakeRShared

func (mounter *Mounter) MakeRShared(path string) error

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) PathIsDevice

func (mounter *Mounter) PathIsDevice(pathname string) (bool, error)

PathIsDevice uses FileInfo returned from os.Stat to check if path refers to a device.

func (*Mounter) PrepareSafeSubpath

func (mounter *Mounter) PrepareSafeSubpath(subPath Subpath) (newHostPath string, cleanupAction func(), err error)

func (*Mounter) SafeMakeDir

func (mounter *Mounter) SafeMakeDir(subdir string, base string, perm os.FileMode) error

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

type Subpath

type Subpath struct {
	// index of the VolumeMount for this container
	VolumeMountIndex int
	// Full path to the subpath directory on the host
	Path string
	// name of the volume that is a valid directory name.
	VolumeName string
	// Full path to the volume path
	VolumePath string
	// Path to the pod's directory, including pod UID
	PodDir string
	// Name of the container
	ContainerName string
}