Simplify addTarFile

We can use tar.FileInfoHeader to do much of the work.

Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)

archive/archive.go

@@ -15,7 +15,6 @@ import (
 	"path/filepath"
 	"strings"
 	"syscall"
-	"time"
 )
 
 type Archive io.Reader
@@ -125,48 +124,33 @@ func (compression *Compression) Extension() string {
 }
 
 func addTarFile(path, name string, tw *tar.Writer) error {
-	var stat syscall.Stat_t
-	if err := syscall.Lstat(path, &stat); err != nil {
+	fi, err := os.Lstat(path)
+	if err != nil {
 		return err
 	}
 
-	mtim := getLastModification(&stat)
-	atim := getLastAccess(&stat)
-	hdr := &tar.Header{
-		Name:       name,
-		Mode:       int64(stat.Mode & 07777),
-		Uid:        int(stat.Uid),
-		Gid:        int(stat.Gid),
-		ModTime:    time.Unix(int64(mtim.Sec), int64(mtim.Nsec)),
-		AccessTime: time.Unix(int64(atim.Sec), int64(atim.Nsec)),
+	link := ""
+	if fi.Mode() & os.ModeSymlink != 0 {
+		if link, err = os.Readlink(path); err != nil {
+			return err
+		}
 	}
 
-	if stat.Mode&syscall.S_IFDIR == syscall.S_IFDIR {
-		hdr.Typeflag = tar.TypeDir
-	} else if stat.Mode&syscall.S_IFLNK == syscall.S_IFLNK {
-		hdr.Typeflag = tar.TypeSymlink
-		if link, err := os.Readlink(path); err != nil {
-			return err
-		} else {
-			hdr.Linkname = link
+	hdr, err := tar.FileInfoHeader(fi, link)
+	if err != nil {
+		return err
+	}
+
+	hdr.Name = name
+
+	stat, ok := fi.Sys().(*syscall.Stat_t)
+	if ok {
+		// Currently go does not fill in the major/minors
+		if stat.Mode&syscall.S_IFBLK == syscall.S_IFBLK ||
+			stat.Mode&syscall.S_IFCHR == syscall.S_IFCHR {
+			hdr.Devmajor = int64(major(uint64(stat.Rdev)))
+			hdr.Devminor = int64(minor(uint64(stat.Rdev)))
 		}
-	} else if stat.Mode&syscall.S_IFBLK == syscall.S_IFBLK ||
-		stat.Mode&syscall.S_IFCHR == syscall.S_IFCHR {
-		if stat.Mode&syscall.S_IFBLK == syscall.S_IFBLK {
-			hdr.Typeflag = tar.TypeBlock
-		} else {
-			hdr.Typeflag = tar.TypeChar
-		}
-		hdr.Devmajor = int64(major(uint64(stat.Rdev)))
-		hdr.Devminor = int64(minor(uint64(stat.Rdev)))
-	} else if stat.Mode&syscall.S_IFIFO == syscall.S_IFIFO ||
-		stat.Mode&syscall.S_IFSOCK == syscall.S_IFSOCK {
-		hdr.Typeflag = tar.TypeFifo
-	} else if stat.Mode&syscall.S_IFREG == syscall.S_IFREG {
-		hdr.Typeflag = tar.TypeReg
-		hdr.Size = stat.Size
-	} else {
-		return fmt.Errorf("Unknown file type: %s\n", path)
 	}
 
 	if err := tw.WriteHeader(hdr); err != nil {