1 /* 2 Copyright The Helm Authors. 3 4 Licensed under the Apache License, Version 2.0 (the "License"); 5 you may not use this file except in compliance with the License. 6 You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10 Unless required by applicable law or agreed to in writing, software 11 distributed under the License is distributed on an "AS IS" BASIS, 12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 See the License for the specific language governing permissions and 14 limitations under the License. 15 */ 16 17 package fileutil 18 19 import ( 20 "io" 21 "os" 22 "path/filepath" 23 24 "helm.sh/helm/v3/internal/third_party/dep/fs" 25 ) 26 27 // AtomicWriteFile atomically (as atomic as os.Rename allows) writes a file to a 28 // disk. 29 func AtomicWriteFile(filename string, reader io.Reader, mode os.FileMode) error { 30 tempFile, err := os.CreateTemp(filepath.Split(filename)) 31 if err != nil { 32 return err 33 } 34 tempName := tempFile.Name() 35 36 if _, err := io.Copy(tempFile, reader); err != nil { 37 tempFile.Close() // return value is ignored as we are already on error path 38 return err 39 } 40 41 if err := tempFile.Close(); err != nil { 42 return err 43 } 44 45 if err := os.Chmod(tempName, mode); err != nil { 46 return err 47 } 48 49 return fs.RenameWithFallback(tempName, filename) 50 } 51