mirror of https://github.com/k3s-io/k3s
105 lines
2.8 KiB
Go
105 lines
2.8 KiB
Go
// Copyright 2015 The etcd Authors
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//
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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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//
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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,
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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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package fileutil
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import (
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"fmt"
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"io"
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"io/ioutil"
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"os"
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"path/filepath"
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"github.com/coreos/pkg/capnslog"
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)
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const (
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// PrivateFileMode grants owner to read/write a file.
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PrivateFileMode = 0600
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// PrivateDirMode grants owner to make/remove files inside the directory.
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PrivateDirMode = 0700
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)
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var plog = capnslog.NewPackageLogger("go.etcd.io/etcd", "pkg/fileutil")
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// IsDirWriteable checks if dir is writable by writing and removing a file
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// to dir. It returns nil if dir is writable.
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func IsDirWriteable(dir string) error {
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f := filepath.Join(dir, ".touch")
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if err := ioutil.WriteFile(f, []byte(""), PrivateFileMode); err != nil {
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return err
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}
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return os.Remove(f)
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}
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// TouchDirAll is similar to os.MkdirAll. It creates directories with 0700 permission if any directory
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// does not exists. TouchDirAll also ensures the given directory is writable.
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func TouchDirAll(dir string) error {
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// If path is already a directory, MkdirAll does nothing
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// and returns nil.
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err := os.MkdirAll(dir, PrivateDirMode)
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if err != nil {
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// if mkdirAll("a/text") and "text" is not
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// a directory, this will return syscall.ENOTDIR
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return err
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}
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return IsDirWriteable(dir)
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}
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// CreateDirAll is similar to TouchDirAll but returns error
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// if the deepest directory was not empty.
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func CreateDirAll(dir string) error {
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err := TouchDirAll(dir)
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if err == nil {
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var ns []string
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ns, err = ReadDir(dir)
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if err != nil {
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return err
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}
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if len(ns) != 0 {
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err = fmt.Errorf("expected %q to be empty, got %q", dir, ns)
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}
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}
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return err
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}
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// Exist returns true if a file or directory exists.
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func Exist(name string) bool {
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_, err := os.Stat(name)
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return err == nil
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}
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// ZeroToEnd zeros a file starting from SEEK_CUR to its SEEK_END. May temporarily
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// shorten the length of the file.
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func ZeroToEnd(f *os.File) error {
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// TODO: support FALLOC_FL_ZERO_RANGE
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off, err := f.Seek(0, io.SeekCurrent)
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if err != nil {
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return err
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}
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lenf, lerr := f.Seek(0, io.SeekEnd)
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if lerr != nil {
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return lerr
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}
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if err = f.Truncate(off); err != nil {
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return err
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}
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// make sure blocks remain allocated
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if err = Preallocate(f, lenf, true); err != nil {
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return err
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}
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_, err = f.Seek(off, io.SeekStart)
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return err
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}
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