Add support for Darwin clonefile

dmcgowan · dmcgowan · commit 30cf84dfb5e0 · 2023-05-16T23:15:10.000-07:00
Signed-off-by: Derek McGowan &lt;derek@mcg.dev&gt;
diff --git a/fs/copy.go b/fs/copy.go
@@ -184,6 +184,10 @@ func copyDirectory(dst, src string, inodes map[uint64]string, o *copyDirOpts) er
 // CopyFile copies the source file to the target.
 // The most efficient means of copying is used for the platform.
 func CopyFile(target, source string) error {
+	return copyFile(target, source)
+}
+
+func openAndCopyFile(target, source string) error {
 	src, err := os.Open(source)
 	if err != nil {
 		return fmt.Errorf("failed to open source %s: %w", source, err)
diff --git a/fs/copy_darwin.go b/fs/copy_darwin.go
@@ -0,0 +1,35 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package fs
+
+import (
+	"errors"
+	"fmt"
+
+	"golang.org/x/sys/unix"
+)
+
+func copyFile(target, source string) error {
+	if err := unix.Clonefile(source, target, unix.CLONE_NOFOLLOW); err != nil {
+		if !errors.Is(err, unix.ENOTSUP) {
+			return fmt.Errorf("clonefile failed: %w", err)
+		}
+
+		return openAndCopyFile(target, source)
+	}
+	return nil
+}
diff --git a/fs/copy_nondarwin.go b/fs/copy_nondarwin.go
@@ -0,0 +1,22 @@
+//go:build !darwin
+// +build !darwin
+
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package fs
+
+var copyFile = openAndCopyFile
