299 lines
8.3 KiB
Go
299 lines
8.3 KiB
Go
// Copyright (C) 2014 The Syncthing Authors.
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//
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// This program is free software: you can redistribute it and/or modify it
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// under the terms of the GNU General Public License as published by the Free
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// Software Foundation, either version 3 of the License, or (at your option)
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// any later version.
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//
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// This program is distributed in the hope that it will be useful, but WITHOUT
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// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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// more details.
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//
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// You should have received a copy of the GNU General Public License along
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// with this program. If not, see <http://www.gnu.org/licenses/>.
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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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"strings"
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"code.google.com/p/go.text/unicode/norm"
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"github.com/syncthing/syncthing/internal/ignore"
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"github.com/syncthing/syncthing/internal/lamport"
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"github.com/syncthing/syncthing/internal/protocol"
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"github.com/syncthing/syncthing/internal/symlinks"
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)
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type Walker struct {
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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 this path within Dir, or no limit if Sub is blank
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Sub 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 tempory files when walking.
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TempNamer TempNamer
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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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// 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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}
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type TempNamer interface {
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// Temporary returns a temporary name for the filed referred to by filepath.
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TempName(path string) string
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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
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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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if debug {
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l.Debugln("Walk", w.Dir, w.Sub, w.BlockSize, w.Matcher)
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}
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err := checkDir(w.Dir)
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if err != nil {
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return nil, err
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}
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files := make(chan protocol.FileInfo)
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hashedFiles := make(chan protocol.FileInfo)
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newParallelHasher(w.Dir, w.BlockSize, runtime.NumCPU(), hashedFiles, files)
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go func() {
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hashFiles := w.walkAndHashFiles(files)
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filepath.Walk(filepath.Join(w.Dir, w.Sub), hashFiles)
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close(files)
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}()
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return hashedFiles, nil
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}
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func (w *Walker) walkAndHashFiles(fchan chan protocol.FileInfo) filepath.WalkFunc {
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return func(p string, info os.FileInfo, err error) error {
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if err != nil {
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if debug {
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l.Debugln("error:", p, info, err)
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}
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return nil
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}
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rn, err := filepath.Rel(w.Dir, p)
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if err != nil {
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if debug {
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l.Debugln("rel error:", p, err)
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}
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return nil
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}
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if rn == "." {
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return nil
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}
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if w.TempNamer != nil && w.TempNamer.IsTemporary(rn) {
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// A temporary file
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if debug {
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l.Debugln("temporary:", rn)
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}
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return nil
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}
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if sn := filepath.Base(rn); sn == ".stignore" || sn == ".stfolder" ||
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strings.HasPrefix(rn, ".stversions") || (w.Matcher != nil && w.Matcher.Match(rn)) {
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// An ignored file
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if debug {
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l.Debugln("ignored:", rn)
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}
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if info.IsDir() {
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return filepath.SkipDir
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}
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return nil
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}
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if (runtime.GOOS == "linux" || runtime.GOOS == "windows") && !norm.NFC.IsNormalString(rn) {
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l.Warnf("File %q contains non-NFC UTF-8 sequences and cannot be synced. Consider renaming.", rn)
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return nil
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}
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// We must perform this check, as symlinks on Windows are always
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// .IsRegular or .IsDir unlike on Unix.
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// Index wise symlinks are always files, regardless of what the target
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// is, because symlinks carry their target path as their content.
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isSymlink, _ := symlinks.IsSymlink(p)
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if isSymlink {
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var rval error
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// If the target is a directory, do NOT descend down there.
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// This will cause files to get tracked, and removing the symlink
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// will as a result remove files in their real location.
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// But do not SkipDir if the target is not a directory, as it will
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// stop scanning the current directory.
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if info.IsDir() {
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rval = filepath.SkipDir
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}
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// We always rehash symlinks as they have no modtime or
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// permissions.
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// We check if they point to the old target by checking that
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// their existing blocks match with the blocks in the index.
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// If we don't have a filer or don't support symlinks, skip.
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if w.CurrentFiler == nil || !symlinks.Supported {
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return rval
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}
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target, flags, err := symlinks.Read(p)
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flags = flags & protocol.SymlinkTypeMask
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if err != nil {
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if debug {
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l.Debugln("readlink error:", p, err)
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}
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return rval
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}
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blocks, err := Blocks(strings.NewReader(target), w.BlockSize, 0)
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if err != nil {
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if debug {
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l.Debugln("hash link error:", p, err)
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}
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return rval
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}
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cf := w.CurrentFiler.CurrentFile(rn)
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if !cf.IsDeleted() && cf.IsSymlink() && SymlinkTypeEqual(flags, cf.Flags) && BlocksEqual(cf.Blocks, blocks) {
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return rval
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}
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f := protocol.FileInfo{
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Name: rn,
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Version: lamport.Default.Tick(0),
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Flags: protocol.FlagSymlink | flags | protocol.FlagNoPermBits | 0666,
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Modified: 0,
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Blocks: blocks,
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}
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if debug {
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l.Debugln("symlink to hash:", p, f)
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}
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fchan <- f
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return rval
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}
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if info.Mode().IsDir() {
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if w.CurrentFiler != nil {
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cf := w.CurrentFiler.CurrentFile(rn)
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permUnchanged := w.IgnorePerms || !cf.HasPermissionBits() || PermsEqual(cf.Flags, uint32(info.Mode()))
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if !cf.IsDeleted() && cf.IsDirectory() && permUnchanged {
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return nil
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}
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}
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var flags uint32 = protocol.FlagDirectory
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if w.IgnorePerms {
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flags |= protocol.FlagNoPermBits | 0777
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} else {
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flags |= uint32(info.Mode() & os.ModePerm)
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}
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f := protocol.FileInfo{
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Name: rn,
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Version: lamport.Default.Tick(0),
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Flags: flags,
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Modified: info.ModTime().Unix(),
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}
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if debug {
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l.Debugln("dir:", p, f)
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}
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fchan <- f
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return nil
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}
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if info.Mode().IsRegular() {
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if w.CurrentFiler != nil {
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cf := w.CurrentFiler.CurrentFile(rn)
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permUnchanged := w.IgnorePerms || !cf.HasPermissionBits() || PermsEqual(cf.Flags, uint32(info.Mode()))
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if !cf.IsDeleted() && cf.Modified == info.ModTime().Unix() && permUnchanged {
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return nil
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}
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if debug {
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l.Debugln("rescan:", cf, info.ModTime().Unix(), info.Mode()&os.ModePerm)
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}
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}
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var flags = uint32(info.Mode() & os.ModePerm)
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if w.IgnorePerms {
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flags = protocol.FlagNoPermBits | 0666
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}
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f := protocol.FileInfo{
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Name: rn,
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Version: lamport.Default.Tick(0),
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Flags: flags,
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Modified: info.ModTime().Unix(),
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}
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if debug {
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l.Debugln("to hash:", p, f)
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}
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fchan <- f
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}
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return nil
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}
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}
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func checkDir(dir string) error {
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if info, err := os.Lstat(dir); err != nil {
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return err
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} else if !info.IsDir() {
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return errors.New(dir + ": not a directory")
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} else if debug {
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l.Debugln("checkDir", 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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// 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.
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// Which means that without this special check a Unix node would be fighting
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// with a Windows node about whether or not the target is known.
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// Basically, if you don't know and someone else knows, just accept it.
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// The fact that you don't know means you are on Unix, and on Unix you don't
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// really care what the target type is. The moment you do know, and if something
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// doesn't match, that will propogate throught the cluster.
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func SymlinkTypeEqual(disk, index uint32) bool {
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if disk&protocol.FlagSymlinkMissingTarget != 0 && index&protocol.FlagSymlinkMissingTarget == 0 {
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return true
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}
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return disk&protocol.SymlinkTypeMask == index&protocol.SymlinkTypeMask
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}
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