Fix invalid argument error on push

With 32ba6ab from #9261, TempArchive now closes the underlying file and
cleans it up as soon as the file's contents have been read. When pushing
an image, PushImageLayerRegistry attempts to call Close() on the layer,
which is a TempArchive that has already been closed. In this situation,
Close() returns an "invalid argument" error.

Add a Close method to TempArchive that does a no-op if the underlying
file has already been closed.

Signed-off-by: Andy Goldstein <agoldste@redhat.com>

archive/archive.go

@@ -771,20 +771,33 @@ func NewTempArchive(src Archive, dir string) (*TempArchive, error) {
 		return nil, err
 	}
 	size := st.Size()
-	return &TempArchive{f, size, 0}, nil
+	return &TempArchive{File: f, Size: size}, nil
 }
 
 type TempArchive struct {
 	*os.File
-	Size int64 // Pre-computed from Stat().Size() as a convenience
-	read int64
+	Size   int64 // Pre-computed from Stat().Size() as a convenience
+	read   int64
+	closed bool
+}
+
+// Close closes the underlying file if it's still open, or does a no-op
+// to allow callers to try to close the TempArchive multiple times safely.
+func (archive *TempArchive) Close() error {
+	if archive.closed {
+		return nil
+	}
+
+	archive.closed = true
+
+	return archive.File.Close()
 }
 
 func (archive *TempArchive) Read(data []byte) (int, error) {
 	n, err := archive.File.Read(data)
 	archive.read += int64(n)
 	if err != nil || archive.read == archive.Size {
-		archive.File.Close()
+		archive.Close()
 		os.Remove(archive.File.Name())
 	}
 	return n, err

archive/archive_test.go

@@ -9,6 +9,7 @@ import (
 	"os/exec"
 	"path"
 	"path/filepath"
+	"strings"
 	"syscall"
 	"testing"
 	"time"
@@ -607,3 +608,18 @@ func TestUntarInvalidSymlink(t *testing.T) {
 		}
 	}
 }
+
+func TestTempArchiveCloseMultipleTimes(t *testing.T) {
+	reader := ioutil.NopCloser(strings.NewReader("hello"))
+	tempArchive, err := NewTempArchive(reader, "")
+	buf := make([]byte, 10)
+	n, err := tempArchive.Read(buf)
+	if n != 5 {
+		t.Fatalf("Expected to read 5 bytes. Read %d instead", n)
+	}
+	for i := 0; i < 3; i++ {
+		if err = tempArchive.Close(); err != nil {
+			t.Fatalf("i=%d. Unexpected error closing temp archive: %v", i, err)
+		}
+	}
+}