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/*
* MinIO Cloud Storage, (C) 2016, 2017, 2018 MinIO, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package cmd
import (
"context"
"io"
"os"
pathutil "path"
"runtime"
"github.com/minio/minio/cmd/logger"
"github.com/minio/minio/pkg/lock"
)
// Removes only the file at given path does not remove
// any parent directories, handles long paths for
// windows automatically.
func fsRemoveFile(ctx context.Context, filePath string) (err error) {
if filePath == "" {
logger.LogIf(ctx, errInvalidArgument)
return errInvalidArgument
}
if err = checkPathLength(filePath); err != nil {
logger.LogIf(ctx, err)
return err
}
if err = os.Remove((filePath)); err != nil {
err = osErrToFSFileErr(err)
if err != errFileNotFound {
logger.LogIf(ctx, err)
}
}
return err
}
// Removes all files and folders at a given path, handles
// long paths for windows automatically.
func fsRemoveAll(ctx context.Context, dirPath string) (err error) {
if dirPath == "" {
logger.LogIf(ctx, errInvalidArgument)
return errInvalidArgument
}
if err = checkPathLength(dirPath); err != nil {
logger.LogIf(ctx, err)
return err
}
if err = removeAll(dirPath); err != nil {
if os.IsPermission(err) {
logger.LogIf(ctx, errVolumeAccessDenied)
return errVolumeAccessDenied
} else if isSysErrNotEmpty(err) {
logger.LogIf(ctx, errVolumeNotEmpty)
return errVolumeNotEmpty
}
logger.LogIf(ctx, err)
return err
}
return nil
}
// Removes a directory only if its empty, handles long
// paths for windows automatically.
func fsRemoveDir(ctx context.Context, dirPath string) (err error) {
if dirPath == "" {
logger.LogIf(ctx, errInvalidArgument)
return errInvalidArgument
}
if err = checkPathLength(dirPath); err != nil {
logger.LogIf(ctx, err)
return err
}
if err = os.Remove((dirPath)); err != nil {
if os.IsNotExist(err) {
return errVolumeNotFound
} else if isSysErrNotEmpty(err) {
return errVolumeNotEmpty
}
logger.LogIf(ctx, err)
return err
}
return nil
}
// Creates a new directory, parent dir should exist
// otherwise returns an error. If directory already
// exists returns an error. Windows long paths
// are handled automatically.
func fsMkdir(ctx context.Context, dirPath string) (err error) {
if dirPath == "" {
logger.LogIf(ctx, errInvalidArgument)
return errInvalidArgument
}
if err = checkPathLength(dirPath); err != nil {
logger.LogIf(ctx, err)
return err
}
if err = os.Mkdir((dirPath), 0777); err != nil {
switch {
case os.IsExist(err):
return errVolumeExists
case os.IsPermission(err):
logger.LogIf(ctx, errDiskAccessDenied)
return errDiskAccessDenied
case isSysErrNotDir(err):
// File path cannot be verified since
// one of the parents is a file.
logger.LogIf(ctx, errDiskAccessDenied)
return errDiskAccessDenied
case isSysErrPathNotFound(err):
// Add specific case for windows.
logger.LogIf(ctx, errDiskAccessDenied)
return errDiskAccessDenied
default:
logger.LogIf(ctx, err)
return err
}
}
return nil
}
// fsStat is a low level call which validates input arguments
// and checks input length upto supported maximum. Does
// not perform any higher layer interpretation of files v/s
// directories. For higher level interpretation look at
// fsStatFileDir, fsStatFile, fsStatDir.
func fsStat(ctx context.Context, statLoc string) (os.FileInfo, error) {
if statLoc == "" {
logger.LogIf(ctx, errInvalidArgument)
return nil, errInvalidArgument
}
if err := checkPathLength(statLoc); err != nil {
logger.LogIf(ctx, err)
return nil, err
}
fi, err := os.Stat(statLoc)
if err != nil {
return nil, err
}
return fi, nil
}
// Lookup if volume exists, returns volume attributes upon success.
func fsStatVolume(ctx context.Context, volume string) (os.FileInfo, error) {
fi, err := fsStat(ctx, volume)
if err != nil {
if os.IsNotExist(err) {
return nil, errVolumeNotFound
} else if os.IsPermission(err) {
return nil, errVolumeAccessDenied
}
return nil, err
}
if !fi.IsDir() {
return nil, errVolumeAccessDenied
}
return fi, nil
}
// Is a one place function which converts all os.PathError
// into a more FS object layer friendly form, converts
// known errors into their typed form for top level
// interpretation.
func osErrToFSFileErr(err error) error {
if err == nil {
return nil
}
if os.IsNotExist(err) {
return errFileNotFound
}
if os.IsPermission(err) {
return errFileAccessDenied
}
if isSysErrNotDir(err) {
return errFileNotFound
}
if isSysErrPathNotFound(err) {
return errFileNotFound
}
if isSysErrTooManyFiles(err) {
return errTooManyOpenFiles
}
return err
}
// Lookup if directory exists, returns directory attributes upon success.
func fsStatDir(ctx context.Context, statDir string) (os.FileInfo, error) {
fi, err := fsStat(ctx, statDir)
if err != nil {
err = osErrToFSFileErr(err)
if err != errFileNotFound {
logger.LogIf(ctx, err)
}
return nil, err
}
if !fi.IsDir() {
return nil, errFileNotFound
}
return fi, nil
}
// Lookup if file exists, returns file attributes upon success.
func fsStatFile(ctx context.Context, statFile string) (os.FileInfo, error) {
fi, err := fsStat(ctx, statFile)
if err != nil {
err = osErrToFSFileErr(err)
if err != errFileNotFound {
logger.LogIf(ctx, err)
}
return nil, err
}
if fi.IsDir() {
return nil, errFileNotFound
}
return fi, nil
}
// Returns if the filePath is a regular file.
func fsIsFile(ctx context.Context, filePath string) bool {
fi, err := fsStat(ctx, filePath)
if err != nil {
return false
}
return fi.Mode().IsRegular()
}
// Opens the file at given path, optionally from an offset. Upon success returns
// a readable stream and the size of the readable stream.
func fsOpenFile(ctx context.Context, readPath string, offset int64) (io.ReadCloser, int64, error) {
if readPath == "" || offset < 0 {
logger.LogIf(ctx, errInvalidArgument)
return nil, 0, errInvalidArgument
}
if err := checkPathLength(readPath); err != nil {
logger.LogIf(ctx, err)
return nil, 0, err
}
fr, err := os.Open(readPath)
if err != nil {
return nil, 0, osErrToFSFileErr(err)
}
// Stat to get the size of the file at path.
st, err := fr.Stat()
if err != nil {
err = osErrToFSFileErr(err)
if err != errFileNotFound {
logger.LogIf(ctx, err)
}
return nil, 0, err
}
// Verify if its not a regular file, since subsequent Seek is undefined.
if !st.Mode().IsRegular() {
logger.LogIf(ctx, errIsNotRegular)
return nil, 0, errIsNotRegular
}
// Seek to the requested offset.
if offset > 0 {
_, err = fr.Seek(offset, io.SeekStart)
if err != nil {
logger.LogIf(ctx, err)
return nil, 0, err
}
}
// Success.
return fr, st.Size(), nil
}
// Creates a file and copies data from incoming reader. Staging buffer is used by io.CopyBuffer.
func fsCreateFile(ctx context.Context, filePath string, reader io.Reader, buf []byte, fallocSize int64) (int64, error) {
if filePath == "" || reader == nil {
logger.LogIf(ctx, errInvalidArgument)
return 0, errInvalidArgument
}
if err := checkPathLength(filePath); err != nil {
logger.LogIf(ctx, err)
return 0, err
}
if err := mkdirAll(pathutil.Dir(filePath), 0777); err != nil {
logger.LogIf(ctx, err)
return 0, err
}
if err := checkDiskFree(pathutil.Dir(filePath), fallocSize); err != nil {
logger.LogIf(ctx, err)
return 0, err
}
writer, err := lock.Open(filePath, os.O_CREATE|os.O_WRONLY, 0666)
if err != nil {
return 0, osErrToFSFileErr(err)
}
defer writer.Close()
// Fallocate only if the size is final object is known.
if fallocSize > 0 {
if err = fsFAllocate(int(writer.Fd()), 0, fallocSize); err != nil {
logger.LogIf(ctx, err)
return 0, err
}
}
var bytesWritten int64
if buf != nil {
bytesWritten, err = io.CopyBuffer(writer, reader, buf)
if err != nil {
if err != io.ErrUnexpectedEOF {
logger.LogIf(ctx, err)
}
return 0, err
}
} else {
bytesWritten, err = io.Copy(writer, reader)
if err != nil {
logger.LogIf(ctx, err)
return 0, err
}
}
return bytesWritten, nil
}
// fsFAllocate is similar to Fallocate but provides a convenient
// wrapper to handle various operating system specific errors.
func fsFAllocate(fd int, offset int64, len int64) (err error) {
e := Fallocate(fd, offset, len)
// Ignore errors when Fallocate is not supported in the current system
if e != nil && !isSysErrNoSys(e) && !isSysErrOpNotSupported(e) {
switch {
case isSysErrNoSpace(e):
err = errDiskFull
case isSysErrIO(e):
err = e
default:
// For errors: EBADF, EINTR, EINVAL, ENODEV, EPERM, ESPIPE and ETXTBSY
// Appending was failed anyway, returns unexpected error
err = errUnexpected
}
return err
}
return nil
}
// Renames source path to destination path, fails if the destination path
// parents are not already created.
func fsSimpleRenameFile(ctx context.Context, sourcePath, destPath string) error {
if err := checkPathLength(sourcePath); err != nil {
logger.LogIf(ctx, err)
return err
}
if err := checkPathLength(destPath); err != nil {
logger.LogIf(ctx, err)
return err
}
if err := os.Rename(sourcePath, destPath); err != nil {
logger.LogIf(ctx, err)
return osErrToFSFileErr(err)
}
return nil
}
// Renames source path to destination path, creates all the
// missing parents if they don't exist.
func fsRenameFile(ctx context.Context, sourcePath, destPath string) error {
if err := checkPathLength(sourcePath); err != nil {
logger.LogIf(ctx, err)
return err
}
if err := checkPathLength(destPath); err != nil {
logger.LogIf(ctx, err)
return err
}
if err := renameAll(sourcePath, destPath); err != nil {
logger.LogIf(ctx, err)
return err
}
return nil
}
// fsDeleteFile is a wrapper for deleteFile(), after checking the path length.
func fsDeleteFile(ctx context.Context, basePath, deletePath string) error {
if err := checkPathLength(basePath); err != nil {
logger.LogIf(ctx, err)
return err
}
if err := checkPathLength(deletePath); err != nil {
logger.LogIf(ctx, err)
return err
}
if err := deleteFile(basePath, deletePath); err != nil {
if err != errFileNotFound {
logger.LogIf(ctx, err)
}
return err
}
return nil
}
// fsRemoveMeta safely removes a locked file and takes care of Windows special case
func fsRemoveMeta(ctx context.Context, basePath, deletePath, tmpDir string) error {
// Special case for windows please read through.
if runtime.GOOS == globalWindowsOSName {
// Ordinarily windows does not permit deletion or renaming of files still
// in use, but if all open handles to that file were opened with FILE_SHARE_DELETE
// then it can permit renames and deletions of open files.
//
// There are however some gotchas with this, and it is worth listing them here.
// Firstly, Windows never allows you to really delete an open file, rather it is
// flagged as delete pending and its entry in its directory remains visible
// (though no new file handles may be opened to it) and when the very last
// open handle to the file in the system is closed, only then is it truly
// deleted. Well, actually only sort of truly deleted, because Windows only
// appears to remove the file entry from the directory, but in fact that
// entry is merely hidden and actually still exists and attempting to create
// a file with the same name will return an access denied error. How long it
// silently exists for depends on a range of factors, but put it this way:
// if your code loops creating and deleting the same file name as you might
// when operating a lock file, you're going
4858
to see lots of random spurious
// access denied errors and truly dismal lock file performance compared to POSIX.
//
// We work-around these un-POSIX file semantics by taking a dual step to
// deleting files. Firstly, it renames the file to tmp location into multipartTmpBucket
// We always open files with FILE_SHARE_DELETE permission enabled, with that
// flag Windows permits renaming and deletion, and because the name was changed
// to a very random name somewhere not in its origin directory before deletion,
// you don't see those unexpected random errors when creating files with the
// same name as a recently deleted file as you do anywhere else on Windows.
// Because the file is probably not in its original containing directory any more,
// deletions of that directory will not fail with "directory not empty" as they
// otherwise normally would either.
tmpPath := pathJoin(tmpDir, mustGetUUID())
fsRenameFile(ctx, deletePath, tmpPath)
// Proceed to deleting the directory if empty
fsDeleteFile(ctx, basePath, pathutil.Dir(deletePath))
// Finally delete the renamed file.
return fsDeleteFile(ctx, tmpDir, tmpPath)
}
return fsDeleteFile(ctx, basePath, deletePath)
}