Unpack filesystem and whitelist from /proc/self/mountinfo

vendor/github.com/containers/image/internal/tmpdir/tmpdir.go

@@ -0,0 +1,19 @@
+package tmpdir
+
+import (
+	"os"
+	"runtime"
+)
+
+// TemporaryDirectoryForBigFiles returns a directory for temporary (big) files.
+// On non Windows systems it avoids the use of os.TempDir(), because the default temporary directory usually falls under /tmp
+// which on systemd based systems could be the unsuitable tmpfs filesystem.
+func TemporaryDirectoryForBigFiles() string {
+	var temporaryDirectoryForBigFiles string
+	if runtime.GOOS == "windows" {
+		temporaryDirectoryForBigFiles = os.TempDir()
+	} else {
+		temporaryDirectoryForBigFiles = "/var/tmp"
+	}
+	return temporaryDirectoryForBigFiles
+}