A bunch of changes

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

cmd/onerng/read.go

@@ -0,0 +1,89 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"time"
+
+	"github.com/pkg/errors"
+
+	"github.com/dustin/go-humanize"
+	"github.com/hairyhenderson/go-onerng"
+	"github.com/spf13/cobra"
+)
+
+func readCmd(ctx context.Context) *cobra.Command {
+	readOut := ""
+	disableAvalanche := false
+	enableRF := false
+	disableWhitener := false
+	enableAESWhiten := true
+
+	count := int64(-1)
+	cmd := &cobra.Command{
+		Use:   "read",
+		Short: "read some random data from the OneRNG",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			o := &onerng.OneRNG{Path: opts.Device}
+			err := o.Init(ctx)
+			if err != nil {
+				return errors.Wrapf(err, "init failed")
+			}
+
+			// set flags based on commandline options
+			flags := onerng.Default
+			if disableAvalanche {
+				flags |= onerng.DisableAvalanche
+			}
+			if enableRF {
+				flags |= onerng.EnableRF
+			}
+			if disableWhitener {
+				flags |= onerng.DisableWhitener
+			}
+
+			// waste some entropy...
+			devNull, err := os.OpenFile("/dev/null", os.O_WRONLY, 0200)
+			if err != nil {
+				return err
+			}
+			_, err = o.Read(ctx, devNull, 10*1024, flags)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "warning: entropy wasteage failed or incomplete, continuing anyway\n")
+			}
+
+			var out io.WriteCloser
+			if readOut == "-" {
+				out = os.Stdout
+			} else {
+				out, err = os.OpenFile(readOut, os.O_RDWR|os.O_CREATE, 0644)
+				if err != nil {
+					return err
+				}
+			}
+
+			if enableAESWhiten {
+				out, err = o.AESWhitener(ctx, out)
+				if err != nil {
+					return err
+				}
+			}
+
+			start := time.Now()
+			written, err := o.Read(ctx, out, count, flags)
+			delta := time.Since(start)
+			rate := float64(written) / delta.Seconds()
+			fmt.Fprintf(os.Stderr, "%s written in %s (%s/s)\n", humanize.Bytes(uint64(written)), delta, humanize.Bytes(uint64(rate)))
+			return err
+		},
+	}
+	cmd.Flags().StringVarP(&readOut, "out", "o", "-", "output file for data (use - for stdout)")
+	cmd.Flags().BoolVar(&disableAvalanche, "disable-avalanche", false, "Disable noise generation from the Avalanche Diode")
+	cmd.Flags().BoolVar(&enableRF, "enable-rf", false, "Enable noise generation from RF")
+	cmd.Flags().BoolVar(&disableWhitener, "disable-whitener", false, "Disable the on-board CRC16 generator")
+	cmd.Flags().Int64VarP(&count, "count", "n", -1, "Read only N bytes (use -1 for unlimited)")
+	cmd.Flags().BoolVar(&enableAESWhiten, "aes-whitener", true, "encrypt with AES-128 to 'whiten' the input stream with a random key obtained from the OneRNG")
+	return cmd
+}