Moved writing files code to file source file.

cmd/csaf_provider/files.go

@@ -1,8 +1,14 @@
 package main
 
 import (
+	"bytes"
+	"crypto/sha256"
+	"crypto/sha512"
 	"errors"
 	"fmt"
+	"hash"
+	"io"
+	"io/ioutil"
 	"math/rand"
 	"os"
 	"path/filepath"
@@ -174,3 +180,37 @@ func mkUniq(prefix string, create func(string) error) (string, error) {
 
 	return "", err
 }
+
+func writeHash(fname, name string, h hash.Hash, data []byte) error {
+
+	if _, err := io.Copy(h, bytes.NewReader(data)); err != nil {
+		return err
+	}
+
+	f, err := os.Create(fname)
+	if err != nil {
+		return err
+	}
+	fmt.Fprintf(f, "%x %s\n", h.Sum(nil), name)
+	return f.Close()
+}
+
+func writeHashedFile(fname, name string, data []byte, armored string) error {
+	// Write the file itself.
+	if err := ioutil.WriteFile(fname, data, 0644); err != nil {
+		return err
+	}
+	// Write SHA256 sum.
+	if err := writeHash(fname+".sha256", name, sha256.New(), data); err != nil {
+		return err
+	}
+	// Write SHA512 sum.
+	if err := writeHash(fname+".sha512", name, sha512.New(), data); err != nil {
+		return err
+	}
+	// Write signature.
+	if err := ioutil.WriteFile(fname+".asc", []byte(armored), 0644); err != nil {
+		return err
+	}
+	return nil
+}