1 files changed, 46 insertions, 0 deletions

diff --git a/cli/internal/cacheitem/restore_regular.go b/cli/internal/cacheitem/restore_regular.go
new file mode 100644
index 0000000..ed8946e
--- /dev/null
+++ b/cli/internal/cacheitem/restore_regular.go
@@ -0,0 +1,46 @@
+package cacheitem
+
+import (
+	"archive/tar"
+	"io"
+	"os"
+
+	"github.com/vercel/turbo/cli/internal/turbopath"
+)
+
+// restoreRegular restores a file.
+func restoreRegular(dirCache *cachedDirTree, anchor turbopath.AbsoluteSystemPath, header *tar.Header, reader *tar.Reader) (turbopath.AnchoredSystemPath, error) {
+	// Assuming this was a `turbo`-created input, we currently have an AnchoredUnixPath.
+	// Assuming this is malicious input we don't really care if we do the wrong thing.
+	processedName, err := canonicalizeName(header.Name)
+	if err != nil {
+		return "", err
+	}
+
+	// We need to traverse `processedName` from base to root split at
+	// `os.Separator` to make sure we don't end up following a symlink
+	// outside of the restore path.
+	if err := safeMkdirFile(dirCache, anchor, processedName, header.Mode); err != nil {
+		return "", err
+	}
+
+	// Create the file.
+	if f, err := processedName.RestoreAnchor(anchor).OpenFile(os.O_WRONLY|os.O_TRUNC|os.O_CREATE, os.FileMode(header.Mode)); err != nil {
+		return "", err
+	} else if _, err := io.Copy(f, reader); err != nil {
+		return "", err
+	} else if err := f.Close(); err != nil {
+		return "", err
+	}
+	return processedName, nil
+}
+
+// safeMkdirAll creates all directories, assuming that the leaf node is a file.
+func safeMkdirFile(dirCache *cachedDirTree, anchor turbopath.AbsoluteSystemPath, processedName turbopath.AnchoredSystemPath, mode int64) error {
+	isRootFile := processedName.Dir() == "."
+	if !isRootFile {
+		return safeMkdirAll(dirCache, anchor, processedName.Dir(), 0755)
+	}
+
+	return nil
+}