cmd/chantools: add new createwallet subcommand

This commit adds a new subcommand for creating a new lnd compatible
wallet.db file from an existing aezeed, master root key (xprv) or by
generating a new aezeed.

cmd/chantools/createwallet.go

@@ -0,0 +1,230 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/btcsuite/btcd/btcutil/hdkeychain"
+	_ "github.com/btcsuite/btcwallet/walletdb/bdb"
+	"github.com/lightninglabs/chantools/lnd"
+	"github.com/lightningnetwork/lnd/aezeed"
+	"github.com/lightningnetwork/lnd/keychain"
+	"github.com/lightningnetwork/lnd/lnwallet"
+	"github.com/lightningnetwork/lnd/lnwallet/btcwallet"
+	"github.com/spf13/cobra"
+)
+
+type createWalletCommand struct {
+	WalletDBDir  string
+	GenerateSeed bool
+
+	rootKey *rootKey
+	cmd     *cobra.Command
+}
+
+func newCreateWalletCommand() *cobra.Command {
+	cc := &createWalletCommand{}
+	cc.cmd = &cobra.Command{
+		Use: "createwallet",
+		Short: "Create a new lnd compatible wallet.db file from an " +
+			"existing seed or by generating a new one",
+		Long: `Creates a new wallet that can be used with lnd or with 
+chantools. The wallet can be created from an existing seed or a new one can be
+generated (use --generateseed).`,
+		Example: `chantools createwallet \
+	--walletdbdir ~/.lnd/data/chain/bitcoin/mainnet`,
+		RunE: cc.Execute,
+	}
+	cc.cmd.Flags().StringVar(
+		&cc.WalletDBDir, "walletdbdir", "", "the folder to create the "+
+			"new wallet.db file in",
+	)
+	cc.cmd.Flags().BoolVar(
+		&cc.GenerateSeed, "generateseed", false, "generate a new "+
+			"seed instead of using an existing one",
+	)
+
+	cc.rootKey = newRootKey(cc.cmd, "creating the new wallet")
+
+	return cc.cmd
+}
+
+func (c *createWalletCommand) Execute(_ *cobra.Command, _ []string) error {
+	var (
+		publicWalletPw  = lnwallet.DefaultPublicPassphrase
+		privateWalletPw = lnwallet.DefaultPrivatePassphrase
+		masterRootKey   *hdkeychain.ExtendedKey
+		birthday        time.Time
+		err             error
+	)
+
+	// Check that we have a wallet DB.
+	if c.WalletDBDir == "" {
+		return fmt.Errorf("wallet DB directory is required")
+	}
+
+	// Make sure the directory (and parents) exists.
+	if err := os.MkdirAll(c.WalletDBDir, 0700); err != nil {
+		return fmt.Errorf("error creating wallet DB directory '%s': %w",
+			c.WalletDBDir, err)
+	}
+
+	// Check if we should create a new seed or read if from the console or
+	// environment.
+	if c.GenerateSeed {
+		fmt.Printf("Generating new lnd compatible aezeed...\n")
+		seed, err := aezeed.New(
+			keychain.KeyDerivationVersionTaproot, nil, time.Now(),
+		)
+		if err != nil {
+			return fmt.Errorf("error creating new seed: %w", err)
+		}
+		birthday = seed.BirthdayTime()
+
+		// Derive the master extended key from the seed.
+		masterRootKey, err = hdkeychain.NewMaster(
+			seed.Entropy[:], chainParams,
+		)
+		if err != nil {
+			return fmt.Errorf("failed to derive master extended "+
+				"key: %w", err)
+		}
+
+		passphrase, err := lnd.ReadPassphrase("shouldn't use")
+		if err != nil {
+			return fmt.Errorf("error reading passphrase: %w", err)
+		}
+
+		mnemonic, err := seed.ToMnemonic(passphrase)
+		if err != nil {
+			return fmt.Errorf("error converting seed to "+
+				"mnemonic: %w", err)
+		}
+
+		fmt.Println("Generated new seed")
+		printCipherSeedWords(mnemonic[:])
+	} else {
+		masterRootKey, birthday, err = c.rootKey.readWithBirthday()
+		if err != nil {
+			return err
+		}
+	}
+
+	// To automate things with chantools, we also offer reading the wallet
+	// password from environment variables.
+	pw := []byte(strings.TrimSpace(os.Getenv(passwordEnvName)))
+
+	// Because we cannot differentiate between an empty and a non-existent
+	// environment variable, we need a special character that indicates that
+	// no password should be used. We use a single dash (-) for that as that
+	// would be too short for an explicit password anyway.
+	switch {
+	// The user indicated in the environment variable that no passphrase
+	// should be used. We don't set any value.
+	case string(pw) == "-":
+
+	// The environment variable didn't contain anything, we'll read the
+	// passphrase from the terminal.
+	case len(pw) == 0:
+		fmt.Printf("\n\nThe wallet password is used to encrypt the " +
+			"wallet.db file itself and is unrelated to the seed.\n")
+		pw, err = passwordFromConsole("Input new wallet password: ")
+		if err != nil {
+			return err
+		}
+		pw2, err := passwordFromConsole("Confirm new wallet password: ")
+		if err != nil {
+			return err
+		}
+
+		if !bytes.Equal(pw, pw2) {
+			return fmt.Errorf("passwords don't match")
+		}
+
+		if len(pw) > 0 {
+			publicWalletPw = pw
+			privateWalletPw = pw
+		}
+
+	// There was a password in the environment, just use it directly.
+	default:
+		publicWalletPw = pw
+		privateWalletPw = pw
+	}
+
+	// Try to create the wallet.
+	loader, err := btcwallet.NewWalletLoader(
+		chainParams, 0, btcwallet.LoaderWithLocalWalletDB(
+			c.WalletDBDir, true, 0,
+		),
+	)
+	if err != nil {
+		return fmt.Errorf("error creating wallet loader: %w", err)
+	}
+
+	_, err = loader.CreateNewWalletExtendedKey(
+		publicWalletPw, privateWalletPw, masterRootKey, birthday,
+	)
+	if err != nil {
+		return fmt.Errorf("error creating new wallet: %w", err)
+	}
+
+	if err := loader.UnloadWallet(); err != nil {
+		return fmt.Errorf("error unloading wallet: %w", err)
+	}
+
+	fmt.Printf("Wallet created successfully at %v\n", c.WalletDBDir)
+
+	return nil
+}
+
+func printCipherSeedWords(mnemonicWords []string) {
+	fmt.Println("!!!YOU MUST WRITE DOWN THIS SEED TO BE ABLE TO " +
+		"RESTORE THE WALLET!!!")
+	fmt.Println()
+
+	fmt.Println("---------------BEGIN LND CIPHER SEED---------------")
+
+	numCols := 4
+	colWords := monoWidthColumns(mnemonicWords, numCols)
+	for i := 0; i < len(colWords); i += numCols {
+		fmt.Printf("%2d. %3s  %2d. %3s  %2d. %3s  %2d. %3s\n",
+			i+1, colWords[i], i+2, colWords[i+1], i+3,
+			colWords[i+2], i+4, colWords[i+3])
+	}
+
+	fmt.Println("---------------END LND CIPHER SEED-----------------")
+
+	fmt.Println("\n!!!YOU MUST WRITE DOWN THIS SEED TO BE ABLE TO " +
+		"RESTORE THE WALLET!!!")
+}
+
+// monoWidthColumns takes a set of words, and the number of desired columns,
+// and returns a new set of words that have had white space appended to the
+// word in order to create a mono-width column.
+func monoWidthColumns(words []string, ncols int) []string {
+	// Determine max size of words in each column.
+	colWidths := make([]int, ncols)
+	for i, word := range words {
+		col := i % ncols
+		curWidth := colWidths[col]
+		if len(word) > curWidth {
+			colWidths[col] = len(word)
+		}
+	}
+
+	// Append whitespace to each word to make columns mono-width.
+	finalWords := make([]string, len(words))
+	for i, word := range words {
+		col := i % ncols
+		width := colWidths[col]
+
+		diff := width - len(word)
+		finalWords[i] = word + strings.Repeat(" ", diff)
+	}
+
+	return finalWords
+}

cmd/chantools/root.go

@@ -101,6 +101,7 @@ func main() {
 	rootCmd.AddCommand(
 		newChanBackupCommand(),
 		newClosePoolAccountCommand(),
+		newCreateWalletCommand(),
 		newCompactDBCommand(),
 		newDeletePaymentsCommand(),
 		newDeriveKeyCommand(),