prepare boot v2

cpiocat/cpiocat.go

@@ -0,0 +1,67 @@
+package cpiocat
+
+import (
+	"io"
+	"os"
+
+	"github.com/cavaliergopher/cpio"
+)
+
+func Append(out io.Writer, in io.Reader, filesToAppend []string) (err error) {
+	cout := cpio.NewWriter(out)
+
+	cin := cpio.NewReader(in)
+
+	for {
+		var hdr *cpio.Header
+		hdr, err = cin.Next()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return
+		}
+
+		err = cout.WriteHeader(hdr)
+		if err != nil {
+			return
+		}
+
+		_, err = io.Copy(cout, cin)
+		if err != nil {
+			return
+		}
+	}
+
+	for _, file := range filesToAppend {
+		err = func() (err error) {
+			stat, err := os.Stat(file)
+			if err != nil {
+				return
+			}
+
+			hdr := &cpio.Header{
+				Name: file,
+				Size: stat.Size(),
+				Mode: cpio.FileMode(stat.Mode()),
+			}
+
+			cout.WriteHeader(hdr)
+
+			f, err := os.Open(file)
+			if err != nil {
+				return
+			}
+			defer f.Close()
+
+			_, err = io.Copy(cout, f)
+			return
+		}()
+		if err != nil {
+			return
+		}
+	}
+
+	err = cout.Close()
+	return
+}