Refactor build

pkg/util/prompt.go

@@ -0,0 +1,90 @@
+package util
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+
+	"github.com/pkg/errors"
+	"golang.org/x/crypto/ssh/terminal"
+)
+
+var (
+	bs       = []byte("\b \b")
+	mask     = []byte("*")
+	maxBytes = 512
+)
+
+func PromptPassword() (string, bool, error) {
+	fmt.Print("Please enter password for [root]: ")
+	p, err := MaskPassword(os.Stdin, os.Stdout)
+	if err != nil {
+		return "", false, errors.Wrapf(err, "failed to set password")
+	}
+	if string(p) == "" {
+		fmt.Printf("Not setting password, leaving root disabled\n")
+		return "", true, nil
+	}
+	fmt.Print("Confirm password for [root]: ")
+	c, err := MaskPassword(os.Stdin, os.Stdout)
+	if err != nil {
+		return "", false, errors.Wrapf(err, "failed to confirm password")
+	}
+	return string(c), bytes.Compare(p, c) == 0, nil
+}
+
+func MaskPassword(r *os.File, w io.Writer) ([]byte, error) {
+	var p []byte
+	var err error
+	fd := int(r.Fd())
+	if terminal.IsTerminal(fd) {
+		s, e := terminal.MakeRaw(fd)
+		if e != nil {
+			return p, e
+		}
+		defer func() {
+			terminal.Restore(fd, s)
+			fmt.Fprintln(w)
+		}()
+	}
+	// Reference: ascii-table-0-127
+	var i int
+	for i = 0; i <= maxBytes; i++ {
+		if v, e := getCharacter(r); e != nil {
+			err = e
+			break
+		} else if v == 127 || v == 8 {
+			// Delete || Backspace
+			if l := len(p); l > 0 {
+				p = p[:l-1]
+				fmt.Fprint(w, string(bs))
+			}
+		} else if v == 13 || v == 10 {
+			// CR || LF
+			break
+		} else if v == 3 {
+			// End
+			err = fmt.Errorf("interrupted")
+			break
+		} else if v != 0 {
+			p = append(p, v)
+			fmt.Fprint(w, string(mask))
+		}
+	}
+	if i > maxBytes {
+		err = fmt.Errorf("maximum password length is %v bytes", maxBytes)
+	}
+	return p, err
+}
+
+func getCharacter(r io.Reader) (byte, error) {
+	buf := make([]byte, 1)
+	if n, err := r.Read(buf); n == 0 || err != nil {
+		if err != nil {
+			return 0, err
+		}
+		return 0, io.EOF
+	}
+	return buf[0], nil
+}