600 lines
17 KiB
Go
600 lines
17 KiB
Go
// Copyright (C) 2014 The Syncthing Authors.
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this file,
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// You can obtain one at http://mozilla.org/MPL/2.0/.
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package scanner
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import (
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"errors"
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"os"
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"path/filepath"
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"runtime"
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"sync/atomic"
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"time"
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"unicode/utf8"
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"github.com/rcrowley/go-metrics"
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"github.com/syncthing/syncthing/lib/events"
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"github.com/syncthing/syncthing/lib/ignore"
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"github.com/syncthing/syncthing/lib/osutil"
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"github.com/syncthing/syncthing/lib/protocol"
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"github.com/syncthing/syncthing/lib/symlinks"
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"golang.org/x/text/unicode/norm"
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)
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var maskModePerm os.FileMode
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func init() {
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if runtime.GOOS == "windows" {
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// There is no user/group/others in Windows' read-only
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// attribute, and all "w" bits are set in os.FileInfo
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// if the file is not read-only. Do not send these
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// group/others-writable bits to other devices in order to
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// avoid unexpected world-writable files on other platforms.
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maskModePerm = os.ModePerm & 0755
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} else {
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maskModePerm = os.ModePerm
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}
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}
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type Config struct {
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// Folder for which the walker has been created
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Folder string
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// Dir is the base directory for the walk
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Dir string
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// Limit walking to these paths within Dir, or no limit if Sub is empty
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Subs []string
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// BlockSize controls the size of the block used when hashing.
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BlockSize int
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// If Matcher is not nil, it is used to identify files to ignore which were specified by the user.
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Matcher *ignore.Matcher
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// If TempNamer is not nil, it is used to ignore temporary files when walking.
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TempNamer TempNamer
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// Number of hours to keep temporary files for
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TempLifetime time.Duration
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// If CurrentFiler is not nil, it is queried for the current file before rescanning.
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CurrentFiler CurrentFiler
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// The Lstater provides reliable mtimes on top of the regular filesystem.
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Lstater Lstater
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// If IgnorePerms is true, changes to permission bits will not be
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// detected. Scanned files will get zero permission bits and the
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// NoPermissionBits flag set.
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IgnorePerms bool
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// When AutoNormalize is set, file names that are in UTF8 but incorrect
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// normalization form will be corrected.
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AutoNormalize bool
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// Number of routines to use for hashing
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Hashers int
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// Our vector clock id
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ShortID protocol.ShortID
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// Optional progress tick interval which defines how often FolderScanProgress
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// events are emitted. Negative number means disabled.
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ProgressTickIntervalS int
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// Signals cancel from the outside - when closed, we should stop walking.
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Cancel chan struct{}
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}
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type TempNamer interface {
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// IsTemporary returns true if path refers to the name of temporary file.
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IsTemporary(path string) bool
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}
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type CurrentFiler interface {
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// CurrentFile returns the file as seen at last scan.
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CurrentFile(name string) (protocol.FileInfo, bool)
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}
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type Lstater interface {
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Lstat(name string) (os.FileInfo, error)
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}
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func Walk(cfg Config) (chan protocol.FileInfo, error) {
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w := walker{cfg}
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if w.CurrentFiler == nil {
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w.CurrentFiler = noCurrentFiler{}
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}
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if w.TempNamer == nil {
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w.TempNamer = noTempNamer{}
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}
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if w.Lstater == nil {
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w.Lstater = defaultLstater{}
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}
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return w.walk()
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}
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type walker struct {
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Config
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}
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// Walk returns the list of files found in the local folder by scanning the
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// file system. Files are blockwise hashed.
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func (w *walker) walk() (chan protocol.FileInfo, error) {
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l.Debugln("Walk", w.Dir, w.Subs, w.BlockSize, w.Matcher)
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if err := w.checkDir(); err != nil {
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return nil, err
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}
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toHashChan := make(chan protocol.FileInfo)
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finishedChan := make(chan protocol.FileInfo)
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// A routine which walks the filesystem tree, and sends files which have
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// been modified to the counter routine.
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go func() {
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hashFiles := w.walkAndHashFiles(toHashChan, finishedChan)
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if len(w.Subs) == 0 {
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filepath.Walk(w.Dir, hashFiles)
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} else {
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for _, sub := range w.Subs {
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filepath.Walk(filepath.Join(w.Dir, sub), hashFiles)
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}
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}
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close(toHashChan)
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}()
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// We're not required to emit scan progress events, just kick off hashers,
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// and feed inputs directly from the walker.
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if w.ProgressTickIntervalS < 0 {
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newParallelHasher(w.Dir, w.BlockSize, w.Hashers, finishedChan, toHashChan, nil, nil, w.Cancel)
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return finishedChan, nil
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}
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// Defaults to every 2 seconds.
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if w.ProgressTickIntervalS == 0 {
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w.ProgressTickIntervalS = 2
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}
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ticker := time.NewTicker(time.Duration(w.ProgressTickIntervalS) * time.Second)
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// We need to emit progress events, hence we create a routine which buffers
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// the list of files to be hashed, counts the total number of
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// bytes to hash, and once no more files need to be hashed (chan gets closed),
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// start a routine which periodically emits FolderScanProgress events,
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// until a stop signal is sent by the parallel hasher.
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// Parallel hasher is stopped by this routine when we close the channel over
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// which it receives the files we ask it to hash.
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go func() {
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var filesToHash []protocol.FileInfo
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var total int64 = 1
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for file := range toHashChan {
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filesToHash = append(filesToHash, file)
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total += file.Size
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}
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realToHashChan := make(chan protocol.FileInfo)
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done := make(chan struct{})
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progress := newByteCounter()
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newParallelHasher(w.Dir, w.BlockSize, w.Hashers, finishedChan, realToHashChan, progress, done, w.Cancel)
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// A routine which actually emits the FolderScanProgress events
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// every w.ProgressTicker ticks, until the hasher routines terminate.
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go func() {
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defer progress.Close()
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for {
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select {
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case <-done:
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l.Debugln("Walk progress done", w.Dir, w.Subs, w.BlockSize, w.Matcher)
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ticker.Stop()
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return
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case <-ticker.C:
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current := progress.Total()
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rate := progress.Rate()
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l.Debugf("Walk %s %s current progress %d/%d at %.01f MiB/s (%d%%)", w.Dir, w.Subs, current, total, rate/1024/1024, current*100/total)
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events.Default.Log(events.FolderScanProgress, map[string]interface{}{
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"folder": w.Folder,
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"current": current,
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"total": total,
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"rate": rate, // bytes per second
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})
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case <-w.Cancel:
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ticker.Stop()
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return
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}
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}
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}()
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loop:
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for _, file := range filesToHash {
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l.Debugln("real to hash:", file.Name)
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select {
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case realToHashChan <- file:
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case <-w.Cancel:
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break loop
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}
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}
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close(realToHashChan)
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}()
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return finishedChan, nil
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}
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func (w *walker) walkAndHashFiles(fchan, dchan chan protocol.FileInfo) filepath.WalkFunc {
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now := time.Now()
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return func(absPath string, info os.FileInfo, err error) error {
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// Return value used when we are returning early and don't want to
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// process the item. For directories, this means do-not-descend.
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var skip error // nil
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// info nil when error is not nil
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if info != nil && info.IsDir() {
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skip = filepath.SkipDir
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}
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if err != nil {
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l.Debugln("error:", absPath, info, err)
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return skip
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}
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relPath, err := filepath.Rel(w.Dir, absPath)
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if err != nil {
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l.Debugln("rel error:", absPath, err)
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return skip
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}
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if relPath == "." {
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return nil
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}
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info, err = w.Lstater.Lstat(absPath)
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// An error here would be weird as we've already gotten to this point, but act on it nonetheless
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if err != nil {
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return skip
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}
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if w.TempNamer.IsTemporary(relPath) {
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l.Debugln("temporary:", relPath)
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if info.Mode().IsRegular() && info.ModTime().Add(w.TempLifetime).Before(now) {
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os.Remove(absPath)
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l.Debugln("removing temporary:", relPath, info.ModTime())
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}
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return nil
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}
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if ignore.IsInternal(relPath) {
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l.Debugln("ignored (internal):", relPath)
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return skip
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}
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if w.Matcher.Match(relPath).IsIgnored() {
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l.Debugln("ignored (patterns):", relPath)
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return skip
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}
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if !utf8.ValidString(relPath) {
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l.Warnf("File name %q is not in UTF8 encoding; skipping.", relPath)
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return skip
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}
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relPath, shouldSkip := w.normalizePath(absPath, relPath)
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if shouldSkip {
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return skip
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}
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switch {
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case info.Mode()&os.ModeSymlink == os.ModeSymlink:
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if err := w.walkSymlink(absPath, relPath, dchan); err != nil {
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return err
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}
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if info.IsDir() {
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// under no circumstances shall we descend into a symlink
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return filepath.SkipDir
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}
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return nil
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case info.Mode().IsDir():
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err = w.walkDir(relPath, info, dchan)
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case info.Mode().IsRegular():
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err = w.walkRegular(relPath, info, fchan)
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}
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return err
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}
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}
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func (w *walker) walkRegular(relPath string, info os.FileInfo, fchan chan protocol.FileInfo) error {
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curMode := uint32(info.Mode())
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if runtime.GOOS == "windows" && osutil.IsWindowsExecutable(relPath) {
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curMode |= 0111
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}
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// A file is "unchanged", if it
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// - exists
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// - has the same permissions as previously, unless we are ignoring permissions
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// - was not marked deleted (since it apparently exists now)
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// - had the same modification time as it has now
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// - was not a directory previously (since it's a file now)
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// - was not a symlink (since it's a file now)
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// - was not invalid (since it looks valid now)
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// - has the same size as previously
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cf, ok := w.CurrentFiler.CurrentFile(relPath)
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permUnchanged := w.IgnorePerms || !cf.HasPermissionBits() || PermsEqual(cf.Permissions, curMode)
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if ok && permUnchanged && !cf.IsDeleted() && cf.ModTime().Equal(info.ModTime()) && !cf.IsDirectory() &&
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!cf.IsSymlink() && !cf.IsInvalid() && cf.Size == info.Size() {
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return nil
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}
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l.Debugln("rescan:", cf, info.ModTime().Unix(), info.Mode()&os.ModePerm)
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f := protocol.FileInfo{
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Name: relPath,
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Type: protocol.FileInfoTypeFile,
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Version: cf.Version.Update(w.ShortID),
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Permissions: curMode & uint32(maskModePerm),
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NoPermissions: w.IgnorePerms,
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ModifiedS: info.ModTime().Unix(),
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ModifiedNs: int32(info.ModTime().Nanosecond()),
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ModifiedBy: w.ShortID,
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Size: info.Size(),
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}
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l.Debugln("to hash:", relPath, f)
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select {
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case fchan <- f:
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case <-w.Cancel:
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return errors.New("cancelled")
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}
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return nil
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}
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func (w *walker) walkDir(relPath string, info os.FileInfo, dchan chan protocol.FileInfo) error {
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// A directory is "unchanged", if it
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// - exists
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// - has the same permissions as previously, unless we are ignoring permissions
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// - was not marked deleted (since it apparently exists now)
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// - was a directory previously (not a file or something else)
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// - was not a symlink (since it's a directory now)
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// - was not invalid (since it looks valid now)
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cf, ok := w.CurrentFiler.CurrentFile(relPath)
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permUnchanged := w.IgnorePerms || !cf.HasPermissionBits() || PermsEqual(cf.Permissions, uint32(info.Mode()))
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if ok && permUnchanged && !cf.IsDeleted() && cf.IsDirectory() && !cf.IsSymlink() && !cf.IsInvalid() {
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return nil
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}
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f := protocol.FileInfo{
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Name: relPath,
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Type: protocol.FileInfoTypeDirectory,
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Version: cf.Version.Update(w.ShortID),
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Permissions: uint32(info.Mode() & maskModePerm),
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NoPermissions: w.IgnorePerms,
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ModifiedS: info.ModTime().Unix(),
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ModifiedNs: int32(info.ModTime().Nanosecond()),
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ModifiedBy: w.ShortID,
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}
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l.Debugln("dir:", relPath, f)
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select {
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case dchan <- f:
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case <-w.Cancel:
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return errors.New("cancelled")
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}
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return nil
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}
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// walkSymlink returns nil or an error, if the error is of the nature that
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// it should stop the entire walk.
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func (w *walker) walkSymlink(absPath, relPath string, dchan chan protocol.FileInfo) error {
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// If the target is a directory, do NOT descend down there. This will
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// cause files to get tracked, and removing the symlink will as a result
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// remove files in their real location.
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if !symlinks.Supported {
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return nil
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}
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// We always rehash symlinks as they have no modtime or
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// permissions. We check if they point to the old target by
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// checking that their existing blocks match with the blocks in
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// the index.
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target, targetType, err := symlinks.Read(absPath)
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if err != nil {
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l.Debugln("readlink error:", absPath, err)
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return nil
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}
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// A symlink is "unchanged", if
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// - it exists
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// - it wasn't deleted (because it isn't now)
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// - it was a symlink
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// - it wasn't invalid
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// - the symlink type (file/dir) was the same
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// - the target was the same
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cf, ok := w.CurrentFiler.CurrentFile(relPath)
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if ok && !cf.IsDeleted() && cf.IsSymlink() && !cf.IsInvalid() && SymlinkTypeEqual(targetType, cf) && cf.SymlinkTarget == target {
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return nil
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}
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f := protocol.FileInfo{
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Name: relPath,
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Type: SymlinkType(targetType),
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Version: cf.Version.Update(w.ShortID),
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NoPermissions: true, // Symlinks don't have permissions of their own
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SymlinkTarget: target,
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}
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l.Debugln("symlink changedb:", absPath, f)
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select {
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case dchan <- f:
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case <-w.Cancel:
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return errors.New("cancelled")
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}
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return nil
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}
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// normalizePath returns the normalized relative path (possibly after fixing
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// it on disk), or skip is true.
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func (w *walker) normalizePath(absPath, relPath string) (normPath string, skip bool) {
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if runtime.GOOS == "darwin" {
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// Mac OS X file names should always be NFD normalized.
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normPath = norm.NFD.String(relPath)
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} else {
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// Every other OS in the known universe uses NFC or just plain
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// doesn't bother to define an encoding. In our case *we* do care,
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// so we enforce NFC regardless.
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normPath = norm.NFC.String(relPath)
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}
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if relPath != normPath {
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// The file name was not normalized.
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if !w.AutoNormalize {
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// We're not authorized to do anything about it, so complain and skip.
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l.Warnf("File name %q is not in the correct UTF8 normalization form; skipping.", relPath)
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return "", true
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}
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// We will attempt to normalize it.
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normalizedPath := filepath.Join(w.Dir, normPath)
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if _, err := w.Lstater.Lstat(normalizedPath); os.IsNotExist(err) {
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// Nothing exists with the normalized filename. Good.
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if err = os.Rename(absPath, normalizedPath); err != nil {
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l.Infof(`Error normalizing UTF8 encoding of file "%s": %v`, relPath, err)
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return "", true
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}
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l.Infof(`Normalized UTF8 encoding of file name "%s".`, relPath)
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} else {
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// There is something already in the way at the normalized
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// file name.
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l.Infof(`File "%s" has UTF8 encoding conflict with another file; ignoring.`, relPath)
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return "", true
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}
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}
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return normPath, false
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}
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func (w *walker) checkDir() error {
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if info, err := w.Lstater.Lstat(w.Dir); err != nil {
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return err
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} else if !info.IsDir() {
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return errors.New(w.Dir + ": not a directory")
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} else {
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l.Debugln("checkDir", w.Dir, info)
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}
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return nil
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}
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func PermsEqual(a, b uint32) bool {
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switch runtime.GOOS {
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case "windows":
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// There is only writeable and read only, represented for user, group
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// and other equally. We only compare against user.
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return a&0600 == b&0600
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default:
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// All bits count
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return a&0777 == b&0777
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}
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}
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func SymlinkTypeEqual(disk symlinks.TargetType, f protocol.FileInfo) bool {
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// If the target is missing, Unix never knows what type of symlink it is
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// and Windows always knows even if there is no target. Which means that
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// without this special check a Unix node would be fighting with a Windows
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// node about whether or not the target is known. Basically, if you don't
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// know and someone else knows, just accept it. The fact that you don't
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// know means you are on Unix, and on Unix you don't really care what the
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// target type is. The moment you do know, and if something doesn't match,
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// that will propagate through the cluster.
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switch disk {
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case symlinks.TargetUnknown:
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return true
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case symlinks.TargetDirectory:
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return f.Type == protocol.FileInfoTypeSymlinkDirectory
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case symlinks.TargetFile:
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return f.Type == protocol.FileInfoTypeSymlinkFile
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}
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panic("unknown symlink TargetType")
|
|
}
|
|
|
|
func SymlinkType(t symlinks.TargetType) protocol.FileInfoType {
|
|
switch t {
|
|
case symlinks.TargetFile:
|
|
return protocol.FileInfoTypeSymlinkFile
|
|
case symlinks.TargetDirectory:
|
|
return protocol.FileInfoTypeSymlinkDirectory
|
|
case symlinks.TargetUnknown:
|
|
return protocol.FileInfoTypeSymlinkUnknown
|
|
}
|
|
panic("unknown symlink TargetType")
|
|
}
|
|
|
|
// A byteCounter gets bytes added to it via Update() and then provides the
|
|
// Total() and one minute moving average Rate() in bytes per second.
|
|
type byteCounter struct {
|
|
total int64
|
|
metrics.EWMA
|
|
stop chan struct{}
|
|
}
|
|
|
|
func newByteCounter() *byteCounter {
|
|
c := &byteCounter{
|
|
EWMA: metrics.NewEWMA1(), // a one minute exponentially weighted moving average
|
|
stop: make(chan struct{}),
|
|
}
|
|
go c.ticker()
|
|
return c
|
|
}
|
|
|
|
func (c *byteCounter) ticker() {
|
|
// The metrics.EWMA expects clock ticks every five seconds in order to
|
|
// decay the average properly.
|
|
t := time.NewTicker(5 * time.Second)
|
|
for {
|
|
select {
|
|
case <-t.C:
|
|
c.Tick()
|
|
case <-c.stop:
|
|
t.Stop()
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
func (c *byteCounter) Update(bytes int64) {
|
|
atomic.AddInt64(&c.total, bytes)
|
|
c.EWMA.Update(bytes)
|
|
}
|
|
|
|
func (c *byteCounter) Total() int64 {
|
|
return atomic.LoadInt64(&c.total)
|
|
}
|
|
|
|
func (c *byteCounter) Close() {
|
|
close(c.stop)
|
|
}
|
|
|
|
// A no-op CurrentFiler
|
|
|
|
type noCurrentFiler struct{}
|
|
|
|
func (noCurrentFiler) CurrentFile(name string) (protocol.FileInfo, bool) {
|
|
return protocol.FileInfo{}, false
|
|
}
|
|
|
|
// A no-op TempNamer
|
|
|
|
type noTempNamer struct{}
|
|
|
|
func (noTempNamer) IsTemporary(path string) bool {
|
|
return false
|
|
}
|
|
|
|
// A no-op Lstater
|
|
|
|
type defaultLstater struct{}
|
|
|
|
func (defaultLstater) Lstat(name string) (os.FileInfo, error) {
|
|
return osutil.Lstat(name)
|
|
}
|