mirror of
https://github.com/ceph/ceph-csi.git
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257 lines
8.5 KiB
Go
257 lines
8.5 KiB
Go
/*
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Copyright 2014 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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// TODO(thockin): This whole pkg is pretty linux-centric. As soon as we have
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// an alternate platform, we will need to abstract further.
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package mount
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import (
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"path/filepath"
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)
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type FileType string
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const (
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// Default mount command if mounter path is not specified
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defaultMountCommand = "mount"
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MountsInGlobalPDPath = "mounts"
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FileTypeDirectory FileType = "Directory"
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FileTypeFile FileType = "File"
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FileTypeSocket FileType = "Socket"
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FileTypeCharDev FileType = "CharDevice"
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FileTypeBlockDev FileType = "BlockDevice"
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)
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type Interface interface {
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// Mount mounts source to target as fstype with given options.
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Mount(source string, target string, fstype string, options []string) error
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// Unmount unmounts given target.
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Unmount(target string) error
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// List returns a list of all mounted filesystems. This can be large.
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// On some platforms, reading mounts is not guaranteed consistent (i.e.
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// it could change between chunked reads). This is guaranteed to be
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// consistent.
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List() ([]MountPoint, error)
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// IsMountPointMatch determines if the mountpoint matches the dir
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IsMountPointMatch(mp MountPoint, dir string) bool
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// IsNotMountPoint determines if a directory is a mountpoint.
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// It should return ErrNotExist when the directory does not exist.
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// IsNotMountPoint is more expensive than IsLikelyNotMountPoint.
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// IsNotMountPoint detects bind mounts in linux.
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// IsNotMountPoint enumerates all the mountpoints using List() and
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// the list of mountpoints may be large, then it uses
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// IsMountPointMatch to evaluate whether the directory is a mountpoint
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IsNotMountPoint(file string) (bool, error)
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// IsLikelyNotMountPoint uses heuristics to determine if a directory
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// is a mountpoint.
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// It should return ErrNotExist when the directory does not exist.
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// IsLikelyNotMountPoint does NOT properly detect all mountpoint types
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// most notably linux bind mounts.
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IsLikelyNotMountPoint(file string) (bool, error)
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// DeviceOpened determines if the device is in use elsewhere
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// on the system, i.e. still mounted.
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DeviceOpened(pathname string) (bool, error)
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// PathIsDevice determines if a path is a device.
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PathIsDevice(pathname string) (bool, error)
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// GetDeviceNameFromMount finds the device name by checking the mount path
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// to get the global mount path which matches its plugin directory
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GetDeviceNameFromMount(mountPath, pluginDir string) (string, error)
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// MakeRShared checks that given path is on a mount with 'rshared' mount
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// propagation. If not, it bind-mounts the path as rshared.
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MakeRShared(path string) error
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// GetFileType checks for file/directory/socket/block/character devices.
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// Will operate in the host mount namespace if kubelet is running in a container
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GetFileType(pathname string) (FileType, error)
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// MakeFile creates an empty file.
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// Will operate in the host mount namespace if kubelet is running in a container
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MakeFile(pathname string) error
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// MakeDir creates a new directory.
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// Will operate in the host mount namespace if kubelet is running in a container
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MakeDir(pathname string) error
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// ExistsPath checks whether the path exists.
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// Will operate in the host mount namespace if kubelet is running in a container
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ExistsPath(pathname string) bool
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}
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// Exec executes command where mount utilities are. This can be either the host,
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// container where kubelet runs or even a remote pod with mount utilities.
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// Usual pkg/util/exec interface is not used because kubelet.RunInContainer does
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// not provide stdin/stdout/stderr streams.
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type Exec interface {
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// Run executes a command and returns its stdout + stderr combined in one
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// stream.
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Run(cmd string, args ...string) ([]byte, error)
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}
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// Compile-time check to ensure all Mounter implementations satisfy
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// the mount interface
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var _ Interface = &Mounter{}
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// This represents a single line in /proc/mounts or /etc/fstab.
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type MountPoint struct {
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Device string
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Path string
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Type string
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Opts []string
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Freq int
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Pass int
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}
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// SafeFormatAndMount probes a device to see if it is formatted.
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// Namely it checks to see if a file system is present. If so it
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// mounts it otherwise the device is formatted first then mounted.
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type SafeFormatAndMount struct {
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Interface
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Exec
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}
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// FormatAndMount formats the given disk, if needed, and mounts it.
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// That is if the disk is not formatted and it is not being mounted as
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// read-only it will format it first then mount it. Otherwise, if the
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// disk is already formatted or it is being mounted as read-only, it
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// will be mounted without formatting.
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func (mounter *SafeFormatAndMount) FormatAndMount(source string, target string, fstype string, options []string) error {
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// Don't attempt to format if mounting as readonly. Go straight to mounting.
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for _, option := range options {
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if option == "ro" {
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return mounter.Interface.Mount(source, target, fstype, options)
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}
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}
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return mounter.formatAndMount(source, target, fstype, options)
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}
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// GetMountRefsByDev finds all references to the device provided
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// by mountPath; returns a list of paths.
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func GetMountRefsByDev(mounter Interface, mountPath string) ([]string, error) {
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mps, err := mounter.List()
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if err != nil {
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return nil, err
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}
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slTarget, err := filepath.EvalSymlinks(mountPath)
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if err != nil {
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slTarget = mountPath
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}
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// Finding the device mounted to mountPath
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diskDev := ""
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for i := range mps {
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if slTarget == mps[i].Path {
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diskDev = mps[i].Device
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break
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}
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}
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// Find all references to the device.
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var refs []string
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for i := range mps {
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if mps[i].Device == diskDev || mps[i].Device == slTarget {
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if mps[i].Path != slTarget {
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refs = append(refs, mps[i].Path)
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}
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}
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}
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return refs, nil
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}
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// GetDeviceNameFromMount: given a mnt point, find the device from /proc/mounts
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// returns the device name, reference count, and error code
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func GetDeviceNameFromMount(mounter Interface, mountPath string) (string, int, error) {
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mps, err := mounter.List()
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if err != nil {
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return "", 0, err
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}
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// Find the device name.
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// FIXME if multiple devices mounted on the same mount path, only the first one is returned
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device := ""
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// If mountPath is symlink, need get its target path.
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slTarget, err := filepath.EvalSymlinks(mountPath)
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if err != nil {
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slTarget = mountPath
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}
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for i := range mps {
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if mps[i].Path == slTarget {
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device = mps[i].Device
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break
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}
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}
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// Find all references to the device.
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refCount := 0
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for i := range mps {
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if mps[i].Device == device {
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refCount++
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}
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}
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return device, refCount, nil
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}
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// IsNotMountPoint determines if a directory is a mountpoint.
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// It should return ErrNotExist when the directory does not exist.
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// This method uses the List() of all mountpoints
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// It is more extensive than IsLikelyNotMountPoint
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// and it detects bind mounts in linux
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func IsNotMountPoint(mounter Interface, file string) (bool, error) {
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// IsLikelyNotMountPoint provides a quick check
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// to determine whether file IS A mountpoint
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notMnt, notMntErr := mounter.IsLikelyNotMountPoint(file)
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if notMntErr != nil {
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return notMnt, notMntErr
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}
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// identified as mountpoint, so return this fact
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if notMnt == false {
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return notMnt, nil
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}
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// check all mountpoints since IsLikelyNotMountPoint
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// is not reliable for some mountpoint types
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mountPoints, mountPointsErr := mounter.List()
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if mountPointsErr != nil {
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return notMnt, mountPointsErr
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}
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for _, mp := range mountPoints {
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if mounter.IsMountPointMatch(mp, file) {
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notMnt = false
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break
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}
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}
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return notMnt, nil
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}
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// isBind detects whether a bind mount is being requested and makes the remount options to
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// use in case of bind mount, due to the fact that bind mount doesn't respect mount options.
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// The list equals:
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// options - 'bind' + 'remount' (no duplicate)
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func isBind(options []string) (bool, []string) {
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bindRemountOpts := []string{"remount"}
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bind := false
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if len(options) != 0 {
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for _, option := range options {
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switch option {
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case "bind":
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bind = true
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break
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case "remount":
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break
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default:
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bindRemountOpts = append(bindRemountOpts, option)
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}
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}
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}
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return bind, bindRemountOpts
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}
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