package wclayer import ( "errors" "os" "path/filepath" "syscall" "github.com/Microsoft/go-winio" "github.com/Microsoft/hcsshim/internal/hcserror" "github.com/Microsoft/hcsshim/internal/safefile" ) type baseLayerWriter struct { root *os.File f *os.File bw *winio.BackupFileWriter err error hasUtilityVM bool dirInfo []dirInfo } type dirInfo struct { path string fileInfo winio.FileBasicInfo } // reapplyDirectoryTimes reapplies directory modification, creation, etc. times // after processing of the directory tree has completed. The times are expected // to be ordered such that parent directories come before child directories. func reapplyDirectoryTimes(root *os.File, dis []dirInfo) error { for i := range dis { di := &dis[len(dis)-i-1] // reverse order: process child directories first f, err := safefile.OpenRelative(di.path, root, syscall.GENERIC_READ|syscall.GENERIC_WRITE, syscall.FILE_SHARE_READ, safefile.FILE_OPEN, safefile.FILE_DIRECTORY_FILE) if err != nil { return err } err = winio.SetFileBasicInfo(f, &di.fileInfo) f.Close() if err != nil { return err } } return nil } func (w *baseLayerWriter) closeCurrentFile() error { if w.f != nil { err := w.bw.Close() err2 := w.f.Close() w.f = nil w.bw = nil if err != nil { return err } if err2 != nil { return err2 } } return nil } func (w *baseLayerWriter) Add(name string, fileInfo *winio.FileBasicInfo) (err error) { defer func() { if err != nil { w.err = err } }() err = w.closeCurrentFile() if err != nil { return err } if filepath.ToSlash(name) == `UtilityVM/Files` { w.hasUtilityVM = true } var f *os.File defer func() { if f != nil { f.Close() } }() extraFlags := uint32(0) if fileInfo.FileAttributes&syscall.FILE_ATTRIBUTE_DIRECTORY != 0 { extraFlags |= safefile.FILE_DIRECTORY_FILE if fileInfo.FileAttributes&syscall.FILE_ATTRIBUTE_REPARSE_POINT == 0 { w.dirInfo = append(w.dirInfo, dirInfo{name, *fileInfo}) } } mode := uint32(syscall.GENERIC_READ | syscall.GENERIC_WRITE | winio.WRITE_DAC | winio.WRITE_OWNER | winio.ACCESS_SYSTEM_SECURITY) f, err = safefile.OpenRelative(name, w.root, mode, syscall.FILE_SHARE_READ, safefile.FILE_CREATE, extraFlags) if err != nil { return hcserror.New(err, "Failed to safefile.OpenRelative", name) } err = winio.SetFileBasicInfo(f, fileInfo) if err != nil { return hcserror.New(err, "Failed to SetFileBasicInfo", name) } w.f = f w.bw = winio.NewBackupFileWriter(f, true) f = nil return nil } func (w *baseLayerWriter) AddLink(name string, target string) (err error) { defer func() { if err != nil { w.err = err } }() err = w.closeCurrentFile() if err != nil { return err } return safefile.LinkRelative(target, w.root, name, w.root) } func (w *baseLayerWriter) Remove(name string) error { return errors.New("base layer cannot have tombstones") } func (w *baseLayerWriter) Write(b []byte) (int, error) { n, err := w.bw.Write(b) if err != nil { w.err = err } return n, err } func (w *baseLayerWriter) Close() error { defer func() { w.root.Close() w.root = nil }() err := w.closeCurrentFile() if err != nil { return err } if w.err == nil { // Restore the file times of all the directories, since they may have // been modified by creating child directories. err = reapplyDirectoryTimes(w.root, w.dirInfo) if err != nil { return err } err = ProcessBaseLayer(w.root.Name()) if err != nil { return err } if w.hasUtilityVM { err := safefile.EnsureNotReparsePointRelative("UtilityVM", w.root) if err != nil { return err } err = ProcessUtilityVMImage(filepath.Join(w.root.Name(), "UtilityVM")) if err != nil { return err } } } return w.err }