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minio/cmd/posix.go

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20 KiB

/*
* Minio Cloud Storage, (C) 2016 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 (
"bytes"
"errors"
"io"
"io/ioutil"
"os"
slashpath "path"
"path/filepath"
"runtime"
"strings"
"sync/atomic"
"syscall"
"github.com/minio/minio/pkg/disk"
)
const (
fsMinFreeSpace = 1024 * 1024 * 1024
fsMinFreeInodesPercent = 5
maxAllowedIOError = 5
)
// posix - implements StorageAPI interface.
type posix struct {
ioErrCount int32 // ref: https://golang.org/pkg/sync/atomic/#pkg-note-BUG
diskPath string
suppliedDiskPath string
minFreeSpace int64
minFreeInodes int64
}
var errFaultyDisk = errors.New("Faulty disk")
// checkPathLength - returns error if given path name length more than 255
func checkPathLength(pathName string) error {
// Apple OS X path length is limited to 1016
if runtime.GOOS == "darwin" && len(pathName) > 1016 {
return errFileNameTooLong
}
// Check each path segment length is > 255
for len(pathName) > 0 && pathName != "." && pathName != "/" {
dir, file := slashpath.Dir(pathName), slashpath.Base(pathName)
if len(file) > 255 {
return errFileNameTooLong
}
pathName = dir
} // Success.
return nil
}
// isDirEmpty - returns whether given directory is empty or not.
func isDirEmpty(dirname string) bool {
f, err := os.Open(dirname)
if err != nil {
errorIf(func() error {
if !os.IsNotExist(err) {
return err
}
return nil
}(), "Unable to access directory.")
return false
}
defer f.Close()
// List one entry.
_, err = f.Readdirnames(1)
if err != io.EOF {
errorIf(func() error {
if !os.IsNotExist(err) {
return err
}
return nil
}(), "Unable to list directory.")
return false
}
// Returns true if we have reached EOF, directory is indeed empty.
return true
}
// Initialize a new storage disk.
func newPosix(diskPath string) (StorageAPI, error) {
if diskPath == "" {
return nil, errInvalidArgument
}
suppliedDiskPath := diskPath
var err error
// Disallow relative paths, figure out absolute paths.
diskPath, err = filepath.Abs(diskPath)
if err != nil {
return nil, err
}
fs := &posix{
suppliedDiskPath: suppliedDiskPath,
diskPath: diskPath,
minFreeSpace: fsMinFreeSpace,
minFreeInodes: fsMinFreeInodesPercent,
}
st, err := os.Stat(preparePath(diskPath))
if err != nil {
if os.IsNotExist(err) {
// Disk not found create it.
err = os.MkdirAll(diskPath, 0777)
return fs, err
}
return fs, err
}
if !st.IsDir() {
return fs, syscall.ENOTDIR
}
return fs, nil
}
// getDiskInfo returns given disk information.
func getDiskInfo(diskPath string) (di disk.Info, err error) {
if err = checkPathLength(diskPath); err == nil {
di, err = disk.GetInfo(diskPath)
}
if os.IsNotExist(err) {
err = errDiskNotFound
}
return di, err
}
// checkDiskFree verifies if disk path has sufficient minimum free disk space and files.
func (s posix) checkDiskFree() (err error) {
di, err := getDiskInfo(s.diskPath)
if err != nil {
return err
}
// Remove 5% from free space for cumulative disk space used for journalling, inodes etc.
availableDiskSpace := float64(di.Free) * 0.95
if int64(availableDiskSpace) <= s.minFreeSpace {
return errDiskFull
}
// Some filesystems do not implement a way to provide total inodes available, instead inodes
// are allocated based on available disk space. For example CephFS, StoreNext CVFS, AzureFile driver.
// Allow for the available disk to be separately validate and we will validate inodes only if
// total inodes are provided by the underlying filesystem.
if di.Files != 0 {
availableFiles := 100 * float64(di.Ffree) / float64(di.Files)
if int64(availableFiles) <= s.minFreeInodes {
return errDiskFull
}
}
// Success.
return nil
}
// Implements stringer compatible interface.
func (s *posix) String() string {
return s.suppliedDiskPath
}
// DiskInfo provides current information about disk space usage,
// total free inodes and underlying filesystem.
func (s *posix) DiskInfo() (info disk.Info, err error) {
return getDiskInfo(s.diskPath)
}
// getVolDir - will convert incoming volume names to
// corresponding valid volume names on the backend in a platform
// compatible way for all operating systems. If volume is not found
// an error is generated.
func (s *posix) getVolDir(volume string) (string, error) {
if !isValidVolname(volume) {
return "", errInvalidArgument
}
volumeDir := pathJoin(s.diskPath, volume)
return volumeDir, nil
}
// Make a volume entry.
func (s *posix) MakeVol(volume string) (err error) {
defer func() {
if err == syscall.EIO {
atomic.AddInt32(&s.ioErrCount, 1)
}
}()
if s.ioErrCount > maxAllowedIOError {
return errFaultyDisk
}
// Validate if disk is free.
if err = s.checkDiskFree(); err != nil {
return err
}
volumeDir, err := s.getVolDir(volume)
if err != nil {
return err
}
// Make a volume entry, with mode 0777 mkdir honors system umask.
err = os.Mkdir(preparePath(volumeDir), 0777)
if err != nil {
if os.IsExist(err) {
return errVolumeExists
} else if os.IsPermission(err) {
return errDiskAccessDenied
}
return err
}
// Success
return nil
}
// ListVols - list volumes.
func (s *posix) ListVols() (volsInfo []VolInfo, err error) {
defer func() {
if err == syscall.EIO {
atomic.AddInt32(&s.ioErrCount, 1)
}
}()
if s.ioErrCount > maxAllowedIOError {
return nil, errFaultyDisk
}
volsInfo, err = listVols(s.diskPath)
if err != nil {
return nil, err
}
for i, vol := range volsInfo {
volInfo := VolInfo{
Name: vol.Name,
Created: vol.Created,
}
volsInfo[i] = volInfo
}
return volsInfo, nil
}
// List all the volumes from diskPath.
func listVols(dirPath string) ([]VolInfo, error) {
if err := checkPathLength(dirPath); err != nil {
return nil, err
}
entries, err := readDir(dirPath)
if err != nil {
return nil, errDiskNotFound
}
var volsInfo []VolInfo
for _, entry := range entries {
if !strings.HasSuffix(entry, slashSeparator) || !isValidVolname(slashpath.Clean(entry)) {
// Skip if entry is neither a directory not a valid volume name.
continue
}
var fi os.FileInfo
fi, err = os.Stat(preparePath(pathJoin(dirPath, entry)))
if err != nil {
// If the file does not exist, skip the entry.
if os.IsNotExist(err) {
continue
}
return nil, err
}
volsInfo = append(volsInfo, VolInfo{
Name: fi.Name(),
// As os.Stat() doesn't carry other than ModTime(), use
// ModTime() as CreatedTime.
Created: fi.ModTime(),
})
}
return volsInfo, nil
}
// StatVol - get volume info.
func (s *posix) StatVol(volume string) (volInfo VolInfo, err error) {
defer func() {
if err == syscall.EIO {
atomic.AddInt32(&s.ioErrCount, 1)
}
}()
if s.ioErrCount > maxAllowedIOError {
return VolInfo{}, errFaultyDisk
}
// Check disk availability.
if _, err = getDiskInfo(s.diskPath); err != nil {
return VolInfo{}, err
}
// Verify if volume is valid and it exists.
volumeDir, err := s.getVolDir(volume)
if err != nil {
return VolInfo{}, err
}
// Stat a volume entry.
var st os.FileInfo
st, err = os.Stat(preparePath(volumeDir))
if err != nil {
if os.IsNotExist(err) {
return VolInfo{}, errVolumeNotFound
}
return VolInfo{}, err
}
// As os.Stat() doesn't carry other than ModTime(), use ModTime()
// as CreatedTime.
createdTime := st.ModTime()
return VolInfo{
Name: volume,
Created: createdTime,
}, nil
}
// DeleteVol - delete a volume.
func (s *posix) DeleteVol(volume string) (err error) {
defer func() {
if err == syscall.EIO {
atomic.AddInt32(&s.ioErrCount, 1)
}
}()
if s.ioErrCount > maxAllowedIOError {
return errFaultyDisk
}
// Check disk availability.
if _, err = getDiskInfo(s.diskPath); err != nil {
return err
}
// Verify if volume is valid and it exists.
volumeDir, err := s.getVolDir(volume)
if err != nil {
return err
}
err = os.Remove(preparePath(volumeDir))
if err != nil {
if os.IsNotExist(err) {
return errVolumeNotFound
} else if isSysErrNotEmpty(err) {
return errVolumeNotEmpty
}
return err
}
return nil
}
// ListDir - return all the entries at the given directory path.
// If an entry is a directory it will be returned with a trailing "/".
func (s *posix) ListDir(volume, dirPath string) (entries []string, err error) {
defer func() {
if err == syscall.EIO {
atomic.AddInt32(&s.ioErrCount, 1)
}
}()
if s.ioErrCount > maxAllowedIOError {
return nil, errFaultyDisk
}
// Check disk availability.
if _, err = getDiskInfo(s.diskPath); err != nil {
return nil, err
}
// Verify if volume is valid and it exists.
volumeDir, err := s.getVolDir(volume)
if err != nil {
return nil, err
}
// Stat a volume entry.
_, err = os.Stat(preparePath(volumeDir))
if err != nil {
if os.IsNotExist(err) {
return nil, errVolumeNotFound
}
return nil, err
}
return readDir(pathJoin(volumeDir, dirPath))
}
// ReadAll reads from r until an error or EOF and returns the data it read.
// A successful call returns err == nil, not err == EOF. Because ReadAll is
// defined to read from src until EOF, it does not treat an EOF from Read
// as an error to be reported.
// This API is meant to be used on files which have small memory footprint, do
// not use this on large files as it would cause server to crash.
func (s *posix) ReadAll(volume, path string) (buf []byte, err error) {
defer func() {
if err == syscall.EIO {
atomic.AddInt32(&s.ioErrCount, 1)
}
}()
if s.ioErrCount > maxAllowedIOError {
return nil, errFaultyDisk
}
// Check disk availability.
if _, err = getDiskInfo(s.diskPath); err != nil {
return nil, err
}
volumeDir, err := s.getVolDir(volume)
if err != nil {
return nil, err
}
// Stat a volume entry.
_, err = os.Stat(preparePath(volumeDir))
if err != nil {
if os.IsNotExist(err) {
return nil, errVolumeNotFound
}
return nil, err
}
// Validate file path length, before reading.
filePath := pathJoin(volumeDir, path)
if err = checkPathLength(filePath); err != nil {
return nil, err
}
// Open the file for reading.
buf, err = ioutil.ReadFile(preparePath(filePath))
if err != nil {
if os.IsNotExist(err) {
return nil, errFileNotFound
} else if os.IsPermission(err) {
return nil, errFileAccessDenied
} else if pathErr, ok := err.(*os.PathError); ok {
switch pathErr.Err {
case syscall.ENOTDIR, syscall.EISDIR:
return nil, errFileNotFound
default:
if isSysErrHandleInvalid(pathErr.Err) {
// This case is special and needs to be handled for windows.
return nil, errFileNotFound
}
}
return nil, pathErr
}
return nil, err
}
return buf, nil
}
// ReadFile reads exactly len(buf) bytes into buf. It returns the
// number of bytes copied. The error is EOF only if no bytes were
// read. On return, n == len(buf) if and only if err == nil. n == 0
// for io.EOF. Additionally ReadFile also starts reading from an
// offset.
func (s *posix) ReadFile(volume string, path string, offset int64, buf []byte) (n int64, err error) {
defer func() {
if err == syscall.EIO {
atomic.AddInt32(&s.ioErrCount, 1)
}
}()
if s.ioErrCount > maxAllowedIOError {
return 0, errFaultyDisk
}
// Check disk availability.
if _, err = getDiskInfo(s.diskPath); err != nil {
return 0, err
}
volumeDir, err := s.getVolDir(volume)
if err != nil {
return 0, err
}
// Stat a volume entry.
_, err = os.Stat(preparePath(volumeDir))
if err != nil {
if os.IsNotExist(err) {
return 0, errVolumeNotFound
}
return 0, err
}
// Validate effective path length before reading.
filePath := pathJoin(volumeDir, path)
if err = checkPathLength(filePath); err != nil {
return 0, err
}
// Open the file for reading.
file, err := os.Open(preparePath(filePath))
if err != nil {
if os.IsNotExist(err) {
return 0, errFileNotFound
} else if os.IsPermission(err) {
return 0, errFileAccessDenied
} else if isSysErrNotDir(err) {
return 0, errFileAccessDenied
}
return 0, err
}
// Close the file descriptor.
defer file.Close()
st, err := file.Stat()
if err != nil {
return 0, err
}
// Verify if its not a regular file, since subsequent Seek is undefined.
if !st.Mode().IsRegular() {
return 0, errIsNotRegular
}
// Seek to requested offset.
_, err = file.Seek(offset, os.SEEK_SET)
if err != nil {
return 0, err
}
// Read full until buffer.
m, err := io.ReadFull(file, buf)
// Success.
return int64(m), err
}
// AppendFile - append a byte array at path, if file doesn't exist at
// path this call explicitly creates it.
func (s *posix) AppendFile(volume, path string, buf []byte) (err error) {
defer func() {
if err == syscall.EIO {
atomic.AddInt32(&s.ioErrCount, 1)
}
}()
if s.ioErrCount > maxAllowedIOError {
return errFaultyDisk
}
// Validate if disk is free.
if err = s.checkDiskFree(); err != nil {
return err
}
volumeDir, err := s.getVolDir(volume)
if err != nil {
return err
}
// Stat a volume entry.
_, err = os.Stat(preparePath(volumeDir))
if err != nil {
if os.IsNotExist(err) {
return errVolumeNotFound
}
return err
}
filePath := pathJoin(volumeDir, path)
if err = checkPathLength(filePath); err != nil {
return err
}
// Verify if the file already exists and is not of regular type.
var st os.FileInfo
if st, err = os.Stat(preparePath(filePath)); err == nil {
if !st.Mode().IsRegular() {
return errIsNotRegular
}
}
// Create top level directories if they don't exist.
// with mode 0777 mkdir honors system umask.
if err = mkdirAll(filepath.Dir(filePath), 0777); err != nil {
// File path cannot be verified since one of the parents is a file.
if isSysErrNotDir(err) {
return errFileAccessDenied
} else if isSysErrPathNotFound(err) {
// Add specific case for windows.
return errFileAccessDenied
}
return err
}
// Creates the named file with mode 0666 (before umask), or starts appending
// to an existig file.
w, err := os.OpenFile(preparePath(filePath), os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0666)
if err != nil {
// File path cannot be verified since one of the parents is a file.
if isSysErrNotDir(err) {
return errFileAccessDenied
}
return err
}
// Close upon return.
defer w.Close()
// Return io.Copy
_, err = io.Copy(w, bytes.NewReader(buf))
return err
}
// StatFile - get file info.
func (s *posix) StatFile(volume, path string) (file FileInfo, err error) {
defer func() {
if err == syscall.EIO {
atomic.AddInt32(&s.ioErrCount, 1)
}
}()
if s.ioErrCount > maxAllowedIOError {
return FileInfo{}, errFaultyDisk
}
// Check disk availability.
if _, err = getDiskInfo(s.diskPath); err != nil {
return FileInfo{}, err
}
volumeDir, err := s.getVolDir(volume)
if err != nil {
return FileInfo{}, err
}
// Stat a volume entry.
_, err = os.Stat(preparePath(volumeDir))
if err != nil {
if os.IsNotExist(err) {
return FileInfo{}, errVolumeNotFound
}
return FileInfo{}, err
}
filePath := slashpath.Join(volumeDir, path)
if err = checkPathLength(filePath); err != nil {
return FileInfo{}, err
}
st, err := os.Stat(preparePath(filePath))
if err != nil {
// File is really not found.
if os.IsNotExist(err) {
return FileInfo{}, errFileNotFound
}
// File path cannot be verified since one of the parents is a file.
if isSysErrNotDir(err) {
return FileInfo{}, errFileNotFound
}
// Return all errors here.
return FileInfo{}, err
}
// If its a directory its not a regular file.
if st.Mode().IsDir() {
return FileInfo{}, errFileNotFound
}
return FileInfo{
Volume: volume,
Name: path,
ModTime: st.ModTime(),
Size: st.Size(),
Mode: st.Mode(),
}, nil
}
// deleteFile - delete file path if its empty.
func deleteFile(basePath, deletePath string) error {
if basePath == deletePath {
return nil
}
// Verify if the path exists.
pathSt, err := os.Stat(preparePath(deletePath))
if err != nil {
if os.IsNotExist(err) {
return errFileNotFound
} else if os.IsPermission(err) {
return errFileAccessDenied
}
return err
}
if pathSt.IsDir() && !isDirEmpty(deletePath) {
// Verify if directory is empty.
return nil
}
// Attempt to remove path.
if err := os.Remove(preparePath(deletePath)); err != nil {
if os.IsNotExist(err) {
return errFileNotFound
} else if os.IsPermission(err) {
return errFileAccessDenied
}
return err
}
// Recursively go down the next path and delete again.
if err := deleteFile(basePath, slashpath.Dir(deletePath)); err != nil {
return err
}
return nil
}
// DeleteFile - delete a file at path.
func (s *posix) DeleteFile(volume, path string) (err error) {
defer func() {
if err == syscall.EIO {
atomic.AddInt32(&s.ioErrCount, 1)
}
}()
if s.ioErrCount > maxAllowedIOError {
return errFaultyDisk
}
// Check disk availability.
if _, err = getDiskInfo(s.diskPath); err != nil {
return err
}
volumeDir, err := s.getVolDir(volume)
if err != nil {
return err
}
// Stat a volume entry.
_, err = os.Stat(preparePath(volumeDir))
if err != nil {
if os.IsNotExist(err) {
return errVolumeNotFound
}
return err
}
// Following code is needed so that we retain "/" suffix if any in
// path argument.
filePath := pathJoin(volumeDir, path)
if err = checkPathLength(filePath); err != nil {
return err
}
// Delete file and delete parent directory as well if its empty.
return deleteFile(volumeDir, filePath)
}
// RenameFile - rename source path to destination path atomically.
func (s *posix) RenameFile(srcVolume, srcPath, dstVolume, dstPath string) (err error) {
defer func() {
if err == syscall.EIO {
atomic.AddInt32(&s.ioErrCount, 1)
}
}()
if s.ioErrCount > maxAllowedIOError {
return errFaultyDisk
}
// Validate if disk is free.
if err = s.checkDiskFree(); err != nil {
return err
}
srcVolumeDir, err := s.getVolDir(srcVolume)
if err != nil {
return err
}
dstVolumeDir, err := s.getVolDir(dstVolume)
if err != nil {
return err
}
// Stat a volume entry.
_, err = os.Stat(preparePath(srcVolumeDir))
if err != nil {
if os.IsNotExist(err) {
return errVolumeNotFound
}
return err
}
_, err = os.Stat(preparePath(dstVolumeDir))
if err != nil {
if os.IsNotExist(err) {
return errVolumeNotFound
}
}
srcIsDir := strings.HasSuffix(srcPath, slashSeparator)
dstIsDir := strings.HasSuffix(dstPath, slashSeparator)
// Either src and dst have to be directories or files, else return error.
if !(srcIsDir && dstIsDir || !srcIsDir && !dstIsDir) {
return errFileAccessDenied
}
srcFilePath := slashpath.Join(srcVolumeDir, srcPath)
if err = checkPathLength(srcFilePath); err != nil {
return err
}
dstFilePath := slashpath.Join(dstVolumeDir, dstPath)
if err = checkPathLength(dstFilePath); err != nil {
return err
}
if srcIsDir {
// If source is a directory we expect the destination to be non-existent always.
_, err = os.Stat(preparePath(dstFilePath))
if err == nil {
return errFileAccessDenied
}
if !os.IsNotExist(err) {
return err
}
// Destination does not exist, hence proceed with the rename.
}
// Creates all the parent directories, with mode 0777 mkdir honors system umask.
if err = mkdirAll(preparePath(slashpath.Dir(dstFilePath)), 0777); err != nil {
// File path cannot be verified since one of the parents is a file.
if isSysErrNotDir(err) {
return errFileAccessDenied
} else if isSysErrPathNotFound(err) {
// This is a special case should be handled only for
// windows, because windows API does not return "not a
// directory" error message. Handle this specifically here.
return errFileAccessDenied
}
return err
}
// Finally attempt a rename.
err = os.Rename(preparePath(srcFilePath), preparePath(dstFilePath))
if err != nil {
if os.IsNotExist(err) {
return errFileNotFound
}
return err
}
return nil
}