253 lines
7.2 KiB
Go
253 lines
7.2 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
|
|
// SPDX-License-Identifier: BSD-3-Clause
|
|
|
|
package taildrop
|
|
|
|
import (
|
|
"crypto/sha256"
|
|
"errors"
|
|
"io"
|
|
"os"
|
|
"path/filepath"
|
|
"sync"
|
|
"time"
|
|
|
|
"tailscale.com/envknob"
|
|
"tailscale.com/ipn"
|
|
"tailscale.com/tstime"
|
|
"tailscale.com/version/distro"
|
|
)
|
|
|
|
type incomingFileKey struct {
|
|
id ClientID
|
|
name string // e.g., "foo.jpeg"
|
|
}
|
|
|
|
type incomingFile struct {
|
|
clock tstime.DefaultClock
|
|
|
|
started time.Time
|
|
size int64 // or -1 if unknown; never 0
|
|
w io.Writer // underlying writer
|
|
sendFileNotify func() // called when done
|
|
partialPath string // non-empty in direct mode
|
|
finalPath string // not used in direct mode
|
|
|
|
mu sync.Mutex
|
|
copied int64
|
|
done bool
|
|
lastNotify time.Time
|
|
}
|
|
|
|
func (f *incomingFile) Write(p []byte) (n int, err error) {
|
|
n, err = f.w.Write(p)
|
|
|
|
var needNotify bool
|
|
defer func() {
|
|
if needNotify {
|
|
f.sendFileNotify()
|
|
}
|
|
}()
|
|
if n > 0 {
|
|
f.mu.Lock()
|
|
defer f.mu.Unlock()
|
|
f.copied += int64(n)
|
|
now := f.clock.Now()
|
|
if f.lastNotify.IsZero() || now.Sub(f.lastNotify) > time.Second {
|
|
f.lastNotify = now
|
|
needNotify = true
|
|
}
|
|
}
|
|
return n, err
|
|
}
|
|
|
|
// PutFile stores a file into [Manager.Dir] from a given client id.
|
|
// The baseName must be a base filename without any slashes.
|
|
// The length is the expected length of content to read from r,
|
|
// it may be negative to indicate that it is unknown.
|
|
// It returns the length of the entire file.
|
|
//
|
|
// If there is a failure reading from r, then the partial file is not deleted
|
|
// for some period of time. The [Manager.PartialFiles] and [Manager.HashPartialFile]
|
|
// methods may be used to list all partial files and to compute the hash for a
|
|
// specific partial file. This allows the client to determine whether to resume
|
|
// a partial file. While resuming, PutFile may be called again with a non-zero
|
|
// offset to specify where to resume receiving data at.
|
|
func (m *Manager) PutFile(id ClientID, baseName string, r io.Reader, offset, length int64) (int64, error) {
|
|
switch {
|
|
case m == nil || m.opts.Dir == "":
|
|
return 0, ErrNoTaildrop
|
|
case !envknob.CanTaildrop():
|
|
return 0, ErrNoTaildrop
|
|
case distro.Get() == distro.Unraid && !m.opts.DirectFileMode:
|
|
return 0, ErrNotAccessible
|
|
}
|
|
dstPath, err := joinDir(m.opts.Dir, baseName)
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
redactAndLogError := func(action string, err error) error {
|
|
err = redactError(err)
|
|
m.opts.Logf("put %v error: %v", action, err)
|
|
return err
|
|
}
|
|
|
|
// Check whether there is an in-progress transfer for the file.
|
|
partialPath := dstPath + id.partialSuffix()
|
|
inFileKey := incomingFileKey{id, baseName}
|
|
inFile, loaded := m.incomingFiles.LoadOrInit(inFileKey, func() *incomingFile {
|
|
inFile := &incomingFile{
|
|
clock: m.opts.Clock,
|
|
started: m.opts.Clock.Now(),
|
|
size: length,
|
|
sendFileNotify: m.opts.SendFileNotify,
|
|
}
|
|
if m.opts.DirectFileMode {
|
|
inFile.partialPath = partialPath
|
|
inFile.finalPath = dstPath
|
|
}
|
|
return inFile
|
|
})
|
|
if loaded {
|
|
return 0, ErrFileExists
|
|
}
|
|
defer m.incomingFiles.Delete(inFileKey)
|
|
m.deleter.Remove(filepath.Base(partialPath)) // avoid deleting the partial file while receiving
|
|
|
|
// Create (if not already) the partial file with read-write permissions.
|
|
f, err := os.OpenFile(partialPath, os.O_CREATE|os.O_RDWR, 0666)
|
|
if err != nil {
|
|
return 0, redactAndLogError("Create", err)
|
|
}
|
|
defer func() {
|
|
f.Close() // best-effort to cleanup dangling file handles
|
|
if err != nil {
|
|
m.deleter.Insert(filepath.Base(partialPath)) // mark partial file for eventual deletion
|
|
}
|
|
}()
|
|
inFile.w = f
|
|
|
|
// Record that we have started to receive at least one file.
|
|
// This is used by the deleter upon a cold-start to scan the directory
|
|
// for any files that need to be deleted.
|
|
if m.opts.State != nil {
|
|
if b, _ := m.opts.State.ReadState(ipn.TaildropReceivedKey); len(b) == 0 {
|
|
if err := m.opts.State.WriteState(ipn.TaildropReceivedKey, []byte{1}); err != nil {
|
|
m.opts.Logf("WriteState error: %v", err) // non-fatal error
|
|
}
|
|
}
|
|
}
|
|
|
|
// A positive offset implies that we are resuming an existing file.
|
|
// Seek to the appropriate offset and truncate the file.
|
|
if offset != 0 {
|
|
currLength, err := f.Seek(0, io.SeekEnd)
|
|
if err != nil {
|
|
return 0, redactAndLogError("Seek", err)
|
|
}
|
|
if offset < 0 || offset > currLength {
|
|
return 0, redactAndLogError("Seek", err)
|
|
}
|
|
if _, err := f.Seek(offset, io.SeekStart); err != nil {
|
|
return 0, redactAndLogError("Seek", err)
|
|
}
|
|
if err := f.Truncate(offset); err != nil {
|
|
return 0, redactAndLogError("Truncate", err)
|
|
}
|
|
}
|
|
|
|
// Copy the contents of the file.
|
|
copyLength, err := io.Copy(inFile, r)
|
|
if err != nil {
|
|
return 0, redactAndLogError("Copy", err)
|
|
}
|
|
if length >= 0 && copyLength != length {
|
|
return 0, redactAndLogError("Copy", errors.New("copied an unexpected number of bytes"))
|
|
}
|
|
if err := f.Close(); err != nil {
|
|
return 0, redactAndLogError("Close", err)
|
|
}
|
|
fileLength := offset + copyLength
|
|
|
|
inFile.mu.Lock()
|
|
inFile.done = true
|
|
inFile.mu.Unlock()
|
|
|
|
// File has been successfully received, rename the partial file
|
|
// to the final destination filename. If a file of that name already exists,
|
|
// then try multiple times with variations of the filename.
|
|
computePartialSum := sync.OnceValues(func() ([sha256.Size]byte, error) {
|
|
return sha256File(partialPath)
|
|
})
|
|
maxRetries := 10
|
|
for ; maxRetries > 0; maxRetries-- {
|
|
// Atomically rename the partial file as the destination file if it doesn't exist.
|
|
// Otherwise, it returns the length of the current destination file.
|
|
// The operation is atomic.
|
|
dstLength, err := func() (int64, error) {
|
|
m.renameMu.Lock()
|
|
defer m.renameMu.Unlock()
|
|
switch fi, err := os.Stat(dstPath); {
|
|
case os.IsNotExist(err):
|
|
return -1, os.Rename(partialPath, dstPath)
|
|
case err != nil:
|
|
return -1, err
|
|
default:
|
|
return fi.Size(), nil
|
|
}
|
|
}()
|
|
if err != nil {
|
|
return 0, redactAndLogError("Rename", err)
|
|
}
|
|
if dstLength < 0 {
|
|
break // we successfully renamed; so stop
|
|
}
|
|
|
|
// Avoid the final rename if a destination file has the same contents.
|
|
//
|
|
// Note: this is best effort and copying files from iOS from the Media Library
|
|
// results in processing on the iOS side which means the size and shas of the
|
|
// same file can be different.
|
|
if dstLength == fileLength {
|
|
partialSum, err := computePartialSum()
|
|
if err != nil {
|
|
return 0, redactAndLogError("Rename", err)
|
|
}
|
|
dstSum, err := sha256File(dstPath)
|
|
if err != nil {
|
|
return 0, redactAndLogError("Rename", err)
|
|
}
|
|
if dstSum == partialSum {
|
|
if err := os.Remove(partialPath); err != nil {
|
|
return 0, redactAndLogError("Remove", err)
|
|
}
|
|
break // we successfully found a content match; so stop
|
|
}
|
|
}
|
|
|
|
// Choose a new destination filename and try again.
|
|
dstPath = NextFilename(dstPath)
|
|
inFile.finalPath = dstPath
|
|
}
|
|
if maxRetries <= 0 {
|
|
return 0, errors.New("too many retries trying to rename partial file")
|
|
}
|
|
m.totalReceived.Add(1)
|
|
m.opts.SendFileNotify()
|
|
return fileLength, nil
|
|
}
|
|
|
|
func sha256File(file string) (out [sha256.Size]byte, err error) {
|
|
h := sha256.New()
|
|
f, err := os.Open(file)
|
|
if err != nil {
|
|
return out, err
|
|
}
|
|
defer f.Close()
|
|
if _, err := io.Copy(h, f); err != nil {
|
|
return out, err
|
|
}
|
|
return [sha256.Size]byte(h.Sum(nil)), nil
|
|
}
|