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Fix review comments for temp file creation

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Add rclone copyright notice for smb files.
Change temp file creation code to match sftp code.
Remove fastrand dependency.
This commit is contained in:
Aneesh Nireshwalia 2023-01-31 17:35:18 -07:00
parent ffea194387
commit 59ecedacaf
4 changed files with 58 additions and 96 deletions
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1
go.mod
View file

@ -26,7 +26,6 @@ require (
github.com/restic/chunker v0.4.0
github.com/spf13/cobra v1.6.1
github.com/spf13/pflag v1.0.5
github.com/valyala/fastrand v1.1.0
golang.org/x/crypto v0.5.0
golang.org/x/net v0.5.0
golang.org/x/oauth2 v0.4.0

2
go.sum
View file

@ -169,8 +169,6 @@ github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKs
github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
github.com/tv42/httpunix v0.0.0-20191220191345-2ba4b9c3382c h1:u6SKchux2yDvFQnDHS3lPnIRmfVJ5Sxy3ao2SIdysLQ=
github.com/tv42/httpunix v0.0.0-20191220191345-2ba4b9c3382c/go.mod h1:hzIxponao9Kjc7aWznkXaL4U4TWaDSs8zcsY4Ka08nM=
github.com/valyala/fastrand v1.1.0 h1:f+5HkLW4rsgzdNoleUOB69hyT9IlD2ZQh9GyDMfb5G8=
github.com/valyala/fastrand v1.1.0/go.mod h1:HWqCzkrkg6QXT8V2EXWvXCoow7vLwOFN002oeRzjapQ=
github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
go.opencensus.io v0.24.0 h1:y73uSU6J157QMP2kn2r30vwW1A2W2WFwSCGnAVxeaD0=
go.opencensus.io v0.24.0/go.mod h1:vNK8G9p7aAivkbmorf4v+7Hgx+Zs0yY+0fOtgBfjQKo=

22
internal/backend/smb/conpool.go
View file

@ -1,3 +1,23 @@
// Parts of this code have been copied from Rclone (https://github.com/rclone)
// Copyright (C) 2012 by Nick Craig-Wood http://www.craig-wood.com/nick/
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package smb
import (
@ -63,7 +83,7 @@ func (b *Backend) getSessions() int32 {
// dial starts a client connection to the given SMB server. It is a
// convenience function that connects to the given network address,
// initiates the SMB handshake, and then sets up a Client.
// initiates the SMB handshake, and then returns a session for SMB communication.
func (b *Backend) dial(ctx context.Context, network, addr string) (*conn, error) {
dialer := net.Dialer{}
tconn, err := dialer.Dial(network, addr)

129
internal/backend/smb/smb.go
View file

@ -1,14 +1,34 @@
// Parts of this code have been copied from Rclone (https://github.com/rclone)
// Copyright (C) 2012 by Nick Craig-Wood http://www.craig-wood.com/nick/
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package smb
import (
"context"
"crypto/rand"
"encoding/hex"
"hash"
"io"
"io/fs"
"os"
"path"
"path/filepath"
"strconv"
"sync"
"syscall"
"time"
@ -21,8 +41,6 @@ import (
"github.com/restic/restic/internal/debug"
"github.com/restic/restic/internal/errors"
"github.com/restic/restic/internal/restic"
"github.com/valyala/fastrand"
)
// Backend stores data on an SMB endpoint.
@ -160,8 +178,9 @@ func (b *Backend) Save(ctx context.Context, h restic.Handle, rd restic.RewindRea
return backoff.Permanent(err)
}
finalname := b.Filename(h)
dir := filepath.Dir(finalname)
filename := b.Filename(h)
tmpFilename := filename + "-restic-temp-" + tempSuffix()
dir := filepath.Dir(tmpFilename)
defer func() {
// Mark non-retriable errors as such
@ -173,9 +192,6 @@ func (b *Backend) Save(ctx context.Context, h restic.Handle, rd restic.RewindRea
b.sem.GetToken()
defer b.sem.ReleaseToken()
// Create new file with a temporary name.
tmpname := filepath.Base(finalname) + "-tmp-"
b.addSession() // Show session in use
defer b.removeSession()
@ -185,7 +201,8 @@ func (b *Backend) Save(ctx context.Context, h restic.Handle, rd restic.RewindRea
}
defer b.putConnection(&cn)
f, err := b.CreateTemp(cn, dir, tmpname)
// create new file
f, err := cn.smbShare.OpenFile(tmpFilename, os.O_CREATE|os.O_EXCL|os.O_WRONLY, 0600)
if b.IsNotExist(err) {
debug.Log("error %v: creating dir", err)
@ -196,7 +213,7 @@ func (b *Backend) Save(ctx context.Context, h restic.Handle, rd restic.RewindRea
debug.Log("error creating dir %v: %v", dir, mkdirErr)
} else {
// try again
f, err = b.CreateTemp(cn, dir, tmpname)
f, err = cn.smbShare.OpenFile(tmpFilename, os.O_CREATE|os.O_EXCL|os.O_WRONLY, 0600)
}
}
@ -237,14 +254,14 @@ func (b *Backend) Save(ctx context.Context, h restic.Handle, rd restic.RewindRea
if err = f.Close(); err != nil {
return errors.WithStack(err)
}
if err = cn.smbShare.Rename(f.Name(), finalname); err != nil {
if err = cn.smbShare.Rename(f.Name(), filename); err != nil {
return errors.WithStack(err)
}
// try to mark file as read-only to avoid accidential modifications
// ignore if the operation fails as some filesystems don't allow the chmod call
// e.g. exfat and network file systems with certain mount options
err = cn.setFileReadonly(finalname, b.Modes.File)
err = cn.setFileReadonly(filename, b.Modes.File)
if err != nil && !os.IsPermission(err) {
return errors.WithStack(err)
}
@ -473,85 +490,13 @@ func (b *Backend) Close() error {
return err
}
const (
pathSeparator = '/' // Always using '/' for SMB
)
// CreateTemp creates a new temporary file in the directory dir,
// opens the file for reading and writing, and returns the resulting file.
// The filename is generated by taking pattern and adding a random string to the end.
// If pattern includes a "*", the random string replaces the last "*".
// If dir is the empty string, CreateTemp uses the default directory for temporary files, as returned by TempDir.
// Multiple programs or goroutines calling CreateTemp simultaneously will not choose the same file.
// The caller can use the file's Name method to find the pathname of the file.
// It is the caller's responsibility to remove the file when it is no longer needed.
func (b *Backend) CreateTemp(cn *conn, dir, pattern string) (*smb2.File, error) {
if dir == "" {
dir = os.TempDir()
}
prefix, suffix, err := prefixAndSuffix(pattern)
// tempSuffix generates a random string suffix that should be sufficiently long
// to avoid accidental conflicts.
func tempSuffix() string {
var nonce [16]byte
_, err := rand.Read(nonce[:])
if err != nil {
return nil, &fs.PathError{Op: "createtemp", Path: pattern, Err: err}
}
prefix = joinPath(dir, prefix)
try := 0
for {
name := prefix + nextRandom() + suffix
f, err := cn.smbShare.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0600)
if os.IsExist(err) {
if try++; try < 10000 {
continue
}
return nil, &fs.PathError{Op: "createtemp", Path: prefix + "*" + suffix, Err: fs.ErrExist}
}
return f, err
panic(err)
}
}
var errPatternHasSeparator = errors.New("pattern contains path separator")
// prefixAndSuffix splits pattern by the last wildcard "*", if applicable,
// returning prefix as the part before "*" and suffix as the part after "*".
func prefixAndSuffix(pattern string) (prefix, suffix string, err error) {
for i := 0; i < len(pattern); i++ {
if IsPathSeparator(pattern[i]) {
return "", "", errPatternHasSeparator
}
}
if pos := lastIndex(pattern, '*'); pos != -1 {
prefix, suffix = pattern[:pos], pattern[pos+1:]
} else {
prefix = pattern
}
return prefix, suffix, nil
}
// LastIndexByte from the strings package.
func lastIndex(s string, sep byte) int {
for i := len(s) - 1; i >= 0; i-- {
if s[i] == sep {
return i
}
}
return -1
}
func nextRandom() string {
return strconv.FormatUint(uint64(fastrand.Uint32()), 10)
}
func joinPath(dir, name string) string {
if len(dir) > 0 && IsPathSeparator(dir[len(dir)-1]) {
return dir + name
}
return dir + string(pathSeparator) + name
}
// IsPathSeparator reports whether c is a directory separator character.
func IsPathSeparator(c uint8) bool {
// NOTE: Windows accepts / as path separator.
return c == '\\' || c == '/'
return hex.EncodeToString(nonce[:])
}