cmd/age: add a prototype of the command line tool

cmd/age/age.go

@@ -0,0 +1,106 @@
+// Copyright 2019 Google LLC
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+package main
+
+import (
+	"crypto/rand"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"time"
+
+	"github.com/FiloSottile/age/internal/age"
+)
+
+func main() {
+	log.SetFlags(0)
+
+	generateFlag := flag.Bool("generate", false, "generate a new age key pair")
+	decryptFlag := flag.Bool("d", false, "decrypt the input")
+	flag.Parse()
+
+	switch {
+	case *generateFlag:
+		if *decryptFlag {
+			log.Fatalf("Invalid flag combination")
+		}
+		generate()
+	case *decryptFlag:
+		if *generateFlag {
+			log.Fatalf("Invalid flag combination")
+		}
+		decrypt()
+	default:
+		encrypt()
+	}
+}
+
+func generate() {
+	if len(flag.Args()) != 0 {
+		log.Fatalf("-generate takes no arguments")
+	}
+
+	key := make([]byte, 32)
+	if _, err := rand.Read(key); err != nil {
+		log.Fatalf("Internal error: %v", err)
+	}
+	k, err := age.NewX25519Identity(key)
+	if err != nil {
+		log.Fatalf("Internal error: %v", err)
+	}
+
+	fmt.Printf("# created: %s\n", time.Now().Format(time.RFC3339))
+	fmt.Printf("# %s\n", k.Recipient())
+	fmt.Printf("%s\n", k)
+}
+
+func encrypt() {
+	var recipients []age.Recipient
+	for _, arg := range flag.Args() {
+		r, err := parseRecipient(arg)
+		if err != nil {
+			log.Fatalf("Error: %v", err)
+		}
+		recipients = append(recipients, r)
+	}
+	if len(recipients) == 0 {
+		log.Fatalf("Missing recipients!")
+	}
+
+	w, err := age.Encrypt(os.Stdout, recipients...)
+	if err != nil {
+		log.Fatalf("Error initializing encryption: %v", err)
+	}
+	if _, err := io.Copy(w, os.Stdin); err != nil {
+		log.Fatalf("Error encrypting the input: %v", err)
+	}
+	if err := w.Close(); err != nil {
+		log.Fatalf("Error finalizing encryption: %v", err)
+	}
+}
+
+func decrypt() {
+	var identities []age.Identity
+	// TODO: use the default location if no arguments are provided.
+	for _, name := range flag.Args() {
+		ids, err := parseIdentitiesFile(name)
+		if err != nil {
+			log.Fatalf("Error: %v", err)
+		}
+		identities = append(identities, ids...)
+	}
+
+	r, err := age.Decrypt(os.Stdin, identities...)
+	if err != nil {
+		log.Fatalf("Error initializing decryption: %v", err)
+	}
+	if _, err := io.Copy(os.Stdout, r); err != nil {
+		log.Fatalf("Error decrypting the input: %v", err)
+	}
+}

cmd/age/parse.go

@@ -0,0 +1,52 @@
+// Copyright 2019 Google LLC
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/FiloSottile/age/internal/age"
+)
+
+func parseRecipient(arg string) (age.Recipient, error) {
+	if strings.HasPrefix(arg, "pubkey:") {
+		return age.ParseX25519Recipient(arg)
+	}
+	return nil, fmt.Errorf("unknown recipient type: %s", arg)
+}
+
+func parseIdentitiesFile(name string) ([]age.Identity, error) {
+	f, err := os.Open(name)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open file: %v", err)
+	}
+
+	var ids []age.Identity
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if strings.HasPrefix(line, "#") || line == "" {
+			continue
+		}
+		i, err := age.ParseX25519Identity(line)
+		if err != nil {
+			return nil, fmt.Errorf("malformed secret keys file %q: %v", name, err)
+		}
+		ids = append(ids, i)
+	}
+	if err := scanner.Err(); err != nil {
+		return nil, fmt.Errorf("failed to read %q: %v", name, err)
+	}
+
+	if len(ids) == 0 {
+		return nil, fmt.Errorf("no secret keys found in %q", name)
+	}
+	return ids, nil
+}