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https://github.com/ceph/ceph-csi.git
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371 lines
12 KiB
Go
371 lines
12 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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"fmt"
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"os"
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"path/filepath"
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"strings"
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utilexec "k8s.io/utils/exec"
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)
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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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// Log message where sensitive mount options were removed
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sensitiveOptionsRemoved = "<masked>"
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)
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// Interface defines the set of methods to allow for mount operations on a system.
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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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// options MUST not contain sensitive material (like passwords).
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Mount(source string, target string, fstype string, options []string) error
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// MountSensitive is the same as Mount() but this method allows
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// sensitiveOptions to be passed in a separate parameter from the normal
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// mount options and ensures the sensitiveOptions are never logged. This
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// method should be used by callers that pass sensitive material (like
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// passwords) as mount options.
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MountSensitive(source string, target string, fstype string, options []string, sensitiveOptions []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 directly from the OS is not guaranteed
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// consistent (i.e. it could change between chunked reads). This is guaranteed
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// to be consistent.
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List() ([]MountPoint, error)
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// IsLikelyNotMountPoint uses heuristics to determine if a directory
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// is not 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 and symbolic link. For callers that do not
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// care about such situations, this is a faster alternative to calling List()
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// and scanning that output.
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IsLikelyNotMountPoint(file string) (bool, error)
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// GetMountRefs finds all mount references to pathname, returning a slice of
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// paths. Pathname can be a mountpoint path or a normal directory
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// (for bind mount). On Linux, pathname is excluded from the slice.
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// For example, if /dev/sdc was mounted at /path/a and /path/b,
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// GetMountRefs("/path/a") would return ["/path/b"]
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// GetMountRefs("/path/b") would return ["/path/a"]
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// On Windows there is no way to query all mount points; as long as pathname is
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// a valid mount, it will be returned.
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GetMountRefs(pathname string) ([]string, 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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// MountPoint 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 // Opts may contain sensitive mount options (like passwords) and MUST be treated as such (e.g. not logged).
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Freq int
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Pass int
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}
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type MountErrorType string
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const (
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FilesystemMismatch MountErrorType = "FilesystemMismatch"
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HasFilesystemErrors MountErrorType = "HasFilesystemErrors"
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UnformattedReadOnly MountErrorType = "UnformattedReadOnly"
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FormatFailed MountErrorType = "FormatFailed"
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GetDiskFormatFailed MountErrorType = "GetDiskFormatFailed"
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UnknownMountError MountErrorType = "UnknownMountError"
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)
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type MountError struct {
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Type MountErrorType
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Message string
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}
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func (mountError MountError) String() string {
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return mountError.Message
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}
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func (mountError MountError) Error() string {
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return mountError.Message
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}
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func NewMountError(mountErrorValue MountErrorType, format string, args ...interface{}) error {
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mountError := MountError{
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Type: mountErrorValue,
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Message: fmt.Sprintf(format, args...),
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}
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return mountError
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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 utilexec.Interface
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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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// options MUST not contain sensitive material (like passwords).
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func (mounter *SafeFormatAndMount) FormatAndMount(source string, target string, fstype string, options []string) error {
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return mounter.FormatAndMountSensitive(source, target, fstype, options, nil /* sensitiveOptions */)
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}
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// FormatAndMountSensitive is the same as FormatAndMount but this method allows
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// sensitiveOptions to be passed in a separate parameter from the normal mount
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// options and ensures the sensitiveOptions are never logged. This method should
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// be used by callers that pass sensitive material (like passwords) as mount
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// options.
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func (mounter *SafeFormatAndMount) FormatAndMountSensitive(source string, target string, fstype string, options []string, sensitiveOptions []string) error {
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return mounter.formatAndMountSensitive(source, target, fstype, options, sensitiveOptions)
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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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// Note that mountPath should be path after the evaluation of any symblolic links.
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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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// Finding the device mounted to mountPath.
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diskDev := ""
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for i := range mps {
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if mountPath == 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 == mountPath {
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if mps[i].Path != mountPath {
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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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// 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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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 && os.IsPermission(notMntErr) {
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// We were not allowed to do the simple stat() check, e.g. on NFS with
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// root_squash. Fall back to /proc/mounts check below.
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notMnt = true
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notMntErr = nil
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}
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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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// Resolve any symlinks in file, kernel would do the same and use the resolved path in /proc/mounts.
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resolvedFile, err := filepath.EvalSymlinks(file)
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if err != nil {
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return true, err
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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 isMountPointMatch(mp, resolvedFile) {
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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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// MakeBindOpts 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 MakeBindOpts(options []string) (bool, []string, []string) {
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bind, bindOpts, bindRemountOpts, _ := MakeBindOptsSensitive(options, nil /* sensitiveOptions */)
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return bind, bindOpts, bindRemountOpts
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}
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// MakeBindOptsSensitive is the same as MakeBindOpts but this method allows
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// sensitiveOptions to be passed in a separate parameter from the normal mount
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// options and ensures the sensitiveOptions are never logged. This method should
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// be used by callers that pass sensitive material (like passwords) as mount
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// options.
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func MakeBindOptsSensitive(options []string, sensitiveOptions []string) (bool, []string, []string, []string) {
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// Because we have an FD opened on the subpath bind mount, the "bind" option
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// needs to be included, otherwise the mount target will error as busy if you
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// remount as readonly.
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//
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// As a consequence, all read only bind mounts will no longer change the underlying
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// volume mount to be read only.
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bindRemountOpts := []string{"bind", "remount"}
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bindRemountSensitiveOpts := []string{}
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bind := false
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bindOpts := []string{"bind"}
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// _netdev is a userspace mount option and does not automatically get added when
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// bind mount is created and hence we must carry it over.
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if checkForNetDev(options, sensitiveOptions) {
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bindOpts = append(bindOpts, "_netdev")
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}
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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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for _, sensitiveOption := range sensitiveOptions {
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switch sensitiveOption {
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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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bindRemountSensitiveOpts = append(bindRemountSensitiveOpts, sensitiveOption)
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}
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}
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return bind, bindOpts, bindRemountOpts, bindRemountSensitiveOpts
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}
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func checkForNetDev(options []string, sensitiveOptions []string) bool {
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for _, option := range options {
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if option == "_netdev" {
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return true
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}
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}
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for _, sensitiveOption := range sensitiveOptions {
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if sensitiveOption == "_netdev" {
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return true
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}
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}
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return false
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}
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// PathWithinBase checks if give path is within given base directory.
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func PathWithinBase(fullPath, basePath string) bool {
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rel, err := filepath.Rel(basePath, fullPath)
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if err != nil {
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return false
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}
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if StartsWithBackstep(rel) {
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// Needed to escape the base path.
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return false
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}
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return true
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}
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// StartsWithBackstep checks if the given path starts with a backstep segment.
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func StartsWithBackstep(rel string) bool {
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// normalize to / and check for ../
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return rel == ".." || strings.HasPrefix(filepath.ToSlash(rel), "../")
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}
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// sanitizedOptionsForLogging will return a comma seperated string containing
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// options and sensitiveOptions. Each entry in sensitiveOptions will be
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// replaced with the string sensitiveOptionsRemoved
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// e.g. o1,o2,<masked>,<masked>
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func sanitizedOptionsForLogging(options []string, sensitiveOptions []string) string {
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seperator := ""
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if len(options) > 0 && len(sensitiveOptions) > 0 {
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seperator = ","
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}
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sensitiveOptionsStart := ""
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sensitiveOptionsEnd := ""
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if len(sensitiveOptions) > 0 {
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sensitiveOptionsStart = strings.Repeat(sensitiveOptionsRemoved+",", len(sensitiveOptions)-1)
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sensitiveOptionsEnd = sensitiveOptionsRemoved
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}
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return strings.Join(options, ",") +
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seperator +
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sensitiveOptionsStart +
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sensitiveOptionsEnd
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}
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