mirror of
https://github.com/ceph/ceph-csi.git
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129 lines
3.8 KiB
Go
129 lines
3.8 KiB
Go
/*
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* path.go - Utility functions for dealing with filesystem paths
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*
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* Copyright 2017 Google Inc.
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* Author: Joe Richey (joerichey@google.com)
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may not
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* use this file except in compliance with the License. You may obtain a copy of
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* the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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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, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations under
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* the License.
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*/
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package filesystem
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import (
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"fmt"
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"log"
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"os"
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"path/filepath"
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"golang.org/x/sys/unix"
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"github.com/pkg/errors"
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)
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// OpenFileOverridingUmask calls os.OpenFile but with the umask overridden so
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// that no permission bits are masked out if the file is created.
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func OpenFileOverridingUmask(name string, flag int, perm os.FileMode) (*os.File, error) {
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oldMask := unix.Umask(0)
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defer unix.Umask(oldMask)
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return os.OpenFile(name, flag, perm)
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}
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// canonicalizePath turns path into an absolute path without symlinks.
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func canonicalizePath(path string) (string, error) {
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path, err := filepath.Abs(path)
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if err != nil {
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return "", err
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}
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path, err = filepath.EvalSymlinks(path)
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// Get a better error if we have an invalid path
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if pathErr, ok := err.(*os.PathError); ok {
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err = errors.Wrap(pathErr.Err, pathErr.Path)
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}
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return path, err
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}
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// loggedStat runs os.Stat, but it logs the error if stat returns any error
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// other than nil or IsNotExist.
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func loggedStat(name string) (os.FileInfo, error) {
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info, err := os.Stat(name)
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if err != nil && !os.IsNotExist(err) {
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log.Print(err)
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}
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return info, err
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}
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// loggedLstat runs os.Lstat (doesn't dereference trailing symlink), but it logs
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// the error if lstat returns any error other than nil or IsNotExist.
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func loggedLstat(name string) (os.FileInfo, error) {
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info, err := os.Lstat(name)
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if err != nil && !os.IsNotExist(err) {
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log.Print(err)
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}
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return info, err
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}
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// isDir returns true if the path exists and is that of a directory.
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func isDir(path string) bool {
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info, err := loggedStat(path)
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return err == nil && info.IsDir()
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}
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// isRegularFile returns true if the path exists and is that of a regular file.
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func isRegularFile(path string) bool {
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info, err := loggedStat(path)
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return err == nil && info.Mode().IsRegular()
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}
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// HaveReadAccessTo returns true if the process has read access to a file or
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// directory, without actually opening it.
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func HaveReadAccessTo(path string) bool {
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return unix.Access(path, unix.R_OK) == nil
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}
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// DeviceNumber represents a combined major:minor device number.
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type DeviceNumber uint64
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func (num DeviceNumber) String() string {
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return fmt.Sprintf("%d:%d", unix.Major(uint64(num)), unix.Minor(uint64(num)))
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}
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func newDeviceNumberFromString(str string) (DeviceNumber, error) {
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var major, minor uint32
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if count, _ := fmt.Sscanf(str, "%d:%d", &major, &minor); count != 2 {
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return 0, errors.Errorf("invalid device number string %q", str)
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}
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return DeviceNumber(unix.Mkdev(major, minor)), nil
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}
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// getDeviceNumber returns the device number of the device node at the given
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// path. If there is a symlink at the path, it is dereferenced.
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func getDeviceNumber(path string) (DeviceNumber, error) {
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var stat unix.Stat_t
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if err := unix.Stat(path, &stat); err != nil {
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return 0, err
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}
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return DeviceNumber(stat.Rdev), nil
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}
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// getNumberOfContainingDevice returns the device number of the filesystem which
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// contains the given file. If the file is a symlink, it is not dereferenced.
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func getNumberOfContainingDevice(path string) (DeviceNumber, error) {
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var stat unix.Stat_t
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if err := unix.Lstat(path, &stat); err != nil {
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return 0, err
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}
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return DeviceNumber(stat.Dev), nil
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}
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