Implement MigrateLegacyToDescriptor

2 files changed, 413 insertions, 0 deletions

diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 3d2d59cf96..90dba5d837 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -3726,4 +3726,400 @@ bool CWallet::MigrateToSQLite(bilingual_str& error)
     assert(committed); // This is a critical error, the new db could not be written to. The original db exists as a backup, but we should not continue execution.
     return true;
 }
+
+std::optional<MigrationData> CWallet::GetDescriptorsForLegacy(bilingual_str& error) const
+{
+    AssertLockHeld(cs_wallet);
+
+    LegacyScriptPubKeyMan* legacy_spkm = GetLegacyScriptPubKeyMan();
+    if (!legacy_spkm) {
+        error = _("Error: This wallet is already a descriptor wallet");
+        return std::nullopt;
+    }
+
+    std::optional<MigrationData> res = legacy_spkm->MigrateToDescriptor();
+    if (res == std::nullopt) {
+        error = _("Error: Unable to produce descriptors for this legacy wallet. Make sure the wallet is unlocked first");
+        return std::nullopt;
+    }
+    return res;
+}
+
+bool CWallet::ApplyMigrationData(MigrationData& data, bilingual_str& error)
+{
+    AssertLockHeld(cs_wallet);
+
+    LegacyScriptPubKeyMan* legacy_spkm = GetLegacyScriptPubKeyMan();
+    if (!legacy_spkm) {
+        error = _("Error: This wallet is already a descriptor wallet");
+        return false;
+    }
+
+    for (auto& desc_spkm : data.desc_spkms) {
+        if (m_spk_managers.count(desc_spkm->GetID()) > 0) {
+            error = _("Error: Duplicate descriptors created during migration. Your wallet may be corrupted.");
+            return false;
+        }
+        m_spk_managers[desc_spkm->GetID()] = std::move(desc_spkm);
+    }
+
+    // Remove the LegacyScriptPubKeyMan from disk
+    if (!legacy_spkm->DeleteRecords()) {
+        return false;
+    }
+
+    // Remove the LegacyScriptPubKeyMan from memory
+    m_spk_managers.erase(legacy_spkm->GetID());
+    m_external_spk_managers.clear();
+    m_internal_spk_managers.clear();
+
+    // Setup new descriptors
+    SetWalletFlag(WALLET_FLAG_DESCRIPTORS);
+    if (!IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
+        // Use the existing master key if we have it
+        if (data.master_key.key.IsValid()) {
+            SetupDescriptorScriptPubKeyMans(data.master_key);
+        } else {
+            // Setup with a new seed if we don't.
+            SetupDescriptorScriptPubKeyMans();
+        }
+    }
+
+    // Check if the transactions in the wallet are still ours. Either they belong here, or they belong in the watchonly wallet.
+    // We need to go through these in the tx insertion order so that lookups to spends works.
+    std::vector<uint256> txids_to_delete;
+    for (const auto& [_pos, wtx] : wtxOrdered) {
+        if (!IsMine(*wtx->tx) && !IsFromMe(*wtx->tx)) {
+            // Check it is the watchonly wallet's
+            // solvable_wallet doesn't need to be checked because transactions for those scripts weren't being watched for
+            if (data.watchonly_wallet) {
+                LOCK(data.watchonly_wallet->cs_wallet);
+                if (data.watchonly_wallet->IsMine(*wtx->tx) || data.watchonly_wallet->IsFromMe(*wtx->tx)) {
+                    // Add to watchonly wallet
+                    if (!data.watchonly_wallet->AddToWallet(wtx->tx, wtx->m_state)) {
+                        error = _("Error: Could not add watchonly tx to watchonly wallet");
+                        return false;
+                    }
+                    // Mark as to remove from this wallet
+                    txids_to_delete.push_back(wtx->GetHash());
+                    continue;
+                }
+            }
+            // Both not ours and not in the watchonly wallet
+            error = strprintf(_("Error: Transaction %s in wallet cannot be identified to belong to migrated wallets"), wtx->GetHash().GetHex());
+            return false;
+        }
+    }
+    // Do the removes
+    if (txids_to_delete.size() > 0) {
+        std::vector<uint256> deleted_txids;
+        if (ZapSelectTx(txids_to_delete, deleted_txids) != DBErrors::LOAD_OK) {
+            error = _("Error: Could not delete watchonly transactions");
+            return false;
+        }
+        if (deleted_txids != txids_to_delete) {
+            error = _("Error: Not all watchonly txs could be deleted");
+            return false;
+        }
+        // Tell the GUI of each tx
+        for (const uint256& txid : deleted_txids) {
+            NotifyTransactionChanged(txid, CT_UPDATED);
+        }
+    }
+
+    // Check the address book data in the same way we did for transactions
+    std::vector<CTxDestination> dests_to_delete;
+    for (const auto& addr_pair : m_address_book) {
+        // Labels applied to receiving addresses should go based on IsMine
+        if (addr_pair.second.purpose == "receive") {
+            if (!IsMine(addr_pair.first)) {
+                // Check the address book data is the watchonly wallet's
+                if (data.watchonly_wallet) {
+                    LOCK(data.watchonly_wallet->cs_wallet);
+                    if (data.watchonly_wallet->IsMine(addr_pair.first)) {
+                        // Add to the watchonly. Preserve the labels, purpose, and change-ness
+                        std::string label = addr_pair.second.GetLabel();
+                        std::string purpose = addr_pair.second.purpose;
+                        if (!purpose.empty()) {
+                            data.watchonly_wallet->m_address_book[addr_pair.first].purpose = purpose;
+                        }
+                        if (!addr_pair.second.IsChange()) {
+                            data.watchonly_wallet->m_address_book[addr_pair.first].SetLabel(label);
+                        }
+                        dests_to_delete.push_back(addr_pair.first);
+                        continue;
+                    }
+                }
+                if (data.solvable_wallet) {
+                    LOCK(data.solvable_wallet->cs_wallet);
+                    if (data.solvable_wallet->IsMine(addr_pair.first)) {
+                        // Add to the solvable. Preserve the labels, purpose, and change-ness
+                        std::string label = addr_pair.second.GetLabel();
+                        std::string purpose = addr_pair.second.purpose;
+                        if (!purpose.empty()) {
+                            data.solvable_wallet->m_address_book[addr_pair.first].purpose = purpose;
+                        }
+                        if (!addr_pair.second.IsChange()) {
+                            data.solvable_wallet->m_address_book[addr_pair.first].SetLabel(label);
+                        }
+                        dests_to_delete.push_back(addr_pair.first);
+                        continue;
+                    }
+                }
+                // Not ours, not in watchonly wallet, and not in solvable
+                error = _("Error: Address book data in wallet cannot be identified to belong to migrated wallets");
+                return false;
+            }
+        } else {
+            // Labels for everything else (send) should be cloned to all
+            if (data.watchonly_wallet) {
+                LOCK(data.watchonly_wallet->cs_wallet);
+                // Add to the watchonly. Preserve the labels, purpose, and change-ness
+                std::string label = addr_pair.second.GetLabel();
+                std::string purpose = addr_pair.second.purpose;
+                if (!purpose.empty()) {
+                    data.watchonly_wallet->m_address_book[addr_pair.first].purpose = purpose;
+                }
+                if (!addr_pair.second.IsChange()) {
+                    data.watchonly_wallet->m_address_book[addr_pair.first].SetLabel(label);
+                }
+                continue;
+            }
+            if (data.solvable_wallet) {
+                LOCK(data.solvable_wallet->cs_wallet);
+                // Add to the solvable. Preserve the labels, purpose, and change-ness
+                std::string label = addr_pair.second.GetLabel();
+                std::string purpose = addr_pair.second.purpose;
+                if (!purpose.empty()) {
+                    data.solvable_wallet->m_address_book[addr_pair.first].purpose = purpose;
+                }
+                if (!addr_pair.second.IsChange()) {
+                    data.solvable_wallet->m_address_book[addr_pair.first].SetLabel(label);
+                }
+                continue;
+            }
+        }
+    }
+    // Remove the things to delete
+    if (dests_to_delete.size() > 0) {
+        for (const auto& dest : dests_to_delete) {
+            if (!DelAddressBook(dest)) {
+                error = _("Error: Unable to remove watchonly address book data");
+                return false;
+            }
+        }
+    }
+
+    // Connect the SPKM signals
+    ConnectScriptPubKeyManNotifiers();
+    NotifyCanGetAddressesChanged();
+
+    WalletLogPrintf("Wallet migration complete.\n");
+
+    return true;
+}
+
+bool DoMigration(CWallet& wallet, WalletContext& context, bilingual_str& error, MigrationResult& res) EXCLUSIVE_LOCKS_REQUIRED(wallet.cs_wallet)
+{
+    AssertLockHeld(wallet.cs_wallet);
+
+    // Get all of the descriptors from the legacy wallet
+    std::optional<MigrationData> data = wallet.GetDescriptorsForLegacy(error);
+    if (data == std::nullopt) return false;
+
+    // Create the watchonly and solvable wallets if necessary
+    if (data->watch_descs.size() > 0 || data->solvable_descs.size() > 0) {
+        DatabaseOptions options;
+        options.require_existing = false;
+        options.require_create = true;
+
+        // Make the wallets
+        options.create_flags = WALLET_FLAG_DISABLE_PRIVATE_KEYS | WALLET_FLAG_BLANK_WALLET | WALLET_FLAG_DESCRIPTORS;
+        if (wallet.IsWalletFlagSet(WALLET_FLAG_AVOID_REUSE)) {
+            options.create_flags |= WALLET_FLAG_AVOID_REUSE;
+        }
+        if (wallet.IsWalletFlagSet(WALLET_FLAG_KEY_ORIGIN_METADATA)) {
+            options.create_flags |= WALLET_FLAG_KEY_ORIGIN_METADATA;
+        }
+        if (data->watch_descs.size() > 0) {
+            wallet.WalletLogPrintf("Making a new watchonly wallet containing the watched scripts\n");
+
+            DatabaseStatus status;
+            std::vector<bilingual_str> warnings;
+            std::string wallet_name = wallet.GetName() + "_watchonly";
+            data->watchonly_wallet = CreateWallet(context, wallet_name, std::nullopt, options, status, error, warnings);
+            if (status != DatabaseStatus::SUCCESS) {
+                error = _("Error: Failed to create new watchonly wallet");
+                return false;
+            }
+            res.watchonly_wallet = data->watchonly_wallet;
+            LOCK(data->watchonly_wallet->cs_wallet);
+
+            // Parse the descriptors and add them to the new wallet
+            for (const auto& [desc_str, creation_time] : data->watch_descs) {
+                // Parse the descriptor
+                FlatSigningProvider keys;
+                std::string parse_err;
+                std::unique_ptr<Descriptor> desc = Parse(desc_str, keys, parse_err, /* require_checksum */ true);
+                assert(desc); // It shouldn't be possible to have the LegacyScriptPubKeyMan make an invalid descriptor
+                assert(!desc->IsRange()); // It shouldn't be possible to have LegacyScriptPubKeyMan make a ranged watchonly descriptor
+
+                // Add to the wallet
+                WalletDescriptor w_desc(std::move(desc), creation_time, 0, 0, 0);
+                data->watchonly_wallet->AddWalletDescriptor(w_desc, keys, "", false);
+            }
+
+            // Add the wallet to settings
+            UpdateWalletSetting(*context.chain, wallet_name, /*load_on_startup=*/true, warnings);
+        }
+        if (data->solvable_descs.size() > 0) {
+            wallet.WalletLogPrintf("Making a new watchonly wallet containing the unwatched solvable scripts\n");
+
+            DatabaseStatus status;
+            std::vector<bilingual_str> warnings;
+            std::string wallet_name = wallet.GetName() + "_solvables";
+            data->solvable_wallet = CreateWallet(context, wallet_name, std::nullopt, options, status, error, warnings);
+            if (status != DatabaseStatus::SUCCESS) {
+                error = _("Error: Failed to create new watchonly wallet");
+                return false;
+            }
+            res.solvables_wallet = data->solvable_wallet;
+            LOCK(data->solvable_wallet->cs_wallet);
+
+            // Parse the descriptors and add them to the new wallet
+            for (const auto& [desc_str, creation_time] : data->solvable_descs) {
+                // Parse the descriptor
+                FlatSigningProvider keys;
+                std::string parse_err;
+                std::unique_ptr<Descriptor> desc = Parse(desc_str, keys, parse_err, /* require_checksum */ true);
+                assert(desc); // It shouldn't be possible to have the LegacyScriptPubKeyMan make an invalid descriptor
+                assert(!desc->IsRange()); // It shouldn't be possible to have LegacyScriptPubKeyMan make a ranged watchonly descriptor
+
+                // Add to the wallet
+                WalletDescriptor w_desc(std::move(desc), creation_time, 0, 0, 0);
+                data->solvable_wallet->AddWalletDescriptor(w_desc, keys, "", false);
+            }
+
+            // Add the wallet to settings
+            UpdateWalletSetting(*context.chain, wallet_name, /*load_on_startup=*/true, warnings);
+        }
+    }
+
+    // Add the descriptors to wallet, remove LegacyScriptPubKeyMan, and cleanup txs and address book data
+    if (!wallet.ApplyMigrationData(*data, error)) {
+        return false;
+    }
+    return true;
+}
+
+util::Result<MigrationResult> MigrateLegacyToDescriptor(std::shared_ptr<CWallet>&& wallet, WalletContext& context)
+{
+    MigrationResult res;
+    bilingual_str error;
+    std::vector<bilingual_str> warnings;
+
+    // Make a backup of the DB
+    std::string wallet_name = wallet->GetName();
+    fs::path this_wallet_dir = fs::absolute(fs::PathFromString(wallet->GetDatabase().Filename())).parent_path();
+    fs::path backup_filename = fs::PathFromString(strprintf("%s-%d.legacy.bak", wallet_name, GetTime()));
+    fs::path backup_path = this_wallet_dir / backup_filename;
+    if (!wallet->BackupWallet(fs::PathToString(backup_path))) {
+        return util::Error{_("Error: Unable to make a backup of your wallet")};
+    }
+    res.backup_path = backup_path;
+
+    // Unload the wallet so that nothing else tries to use it while we're changing it
+    if (!RemoveWallet(context, wallet, /*load_on_start=*/std::nullopt, warnings)) {
+        return util::Error{_("Unable to unload the wallet before migrating")};
+    }
+    UnloadWallet(std::move(wallet));
+
+    // Load the wallet but only in the context of this function.
+    // No signals should be connected nor should anything else be aware of this wallet
+    WalletContext empty_context;
+    empty_context.args = context.args;
+    DatabaseOptions options;
+    options.require_existing = true;
+    DatabaseStatus status;
+    std::unique_ptr<WalletDatabase> database = MakeWalletDatabase(wallet_name, options, status, error);
+    if (!database) {
+        return util::Error{Untranslated("Wallet file verification failed.") + Untranslated(" ") + error};
+    }
+
+    std::shared_ptr<CWallet> local_wallet = CWallet::Create(empty_context, wallet_name, std::move(database), options.create_flags, error, warnings);
+    if (!local_wallet) {
+        return util::Error{Untranslated("Wallet loading failed.") + Untranslated(" ") + error};
+    }
+
+    bool success = false;
+    {
+        LOCK(local_wallet->cs_wallet);
+
+        // First change to using SQLite
+        if (!local_wallet->MigrateToSQLite(error)) return util::Error{error};
+
+        // Do the migration, and cleanup if it fails
+        success = DoMigration(*local_wallet, context, error, res);
+    }
+
+    if (success) {
+        // Migration successful, unload the wallet locally, then reload it.
+        assert(local_wallet.use_count() == 1);
+        local_wallet.reset();
+        LoadWallet(context, wallet_name, /*load_on_start=*/std::nullopt, options, status, error, warnings);
+        res.wallet_name = wallet_name;
+    } else {
+        // Migration failed, cleanup
+        // Copy the backup to the actual wallet dir
+        fs::path temp_backup_location = fsbridge::AbsPathJoin(GetWalletDir(), backup_filename);
+        fs::copy_file(backup_path, temp_backup_location, fs::copy_options::none);
+
+        // Remember this wallet's walletdir to remove after unloading
+        std::vector<fs::path> wallet_dirs;
+        wallet_dirs.push_back(fs::PathFromString(local_wallet->GetDatabase().Filename()).parent_path());
+
+        // Unload the wallet locally
+        assert(local_wallet.use_count() == 1);
+        local_wallet.reset();
+
+        // Make list of wallets to cleanup
+        std::vector<std::shared_ptr<CWallet>> created_wallets;
+        created_wallets.push_back(std::move(res.watchonly_wallet));
+        created_wallets.push_back(std::move(res.solvables_wallet));
+
+        // Get the directories to remove after unloading
+        for (std::shared_ptr<CWallet>& w : created_wallets) {
+            wallet_dirs.push_back(fs::PathFromString(w->GetDatabase().Filename()).parent_path());
+        }
+
+        // Unload the wallets
+        for (std::shared_ptr<CWallet>& w : created_wallets) {
+            if (!RemoveWallet(context, w, /*load_on_start=*/false)) {
+                error += _("\nUnable to cleanup failed migration");
+                return util::Error{error};
+            }
+            UnloadWallet(std::move(w));
+        }
+
+        // Delete the wallet directories
+        for (fs::path& dir : wallet_dirs) {
+            fs::remove_all(dir);
+        }
+
+        // Restore the backup
+        DatabaseStatus status;
+        std::vector<bilingual_str> warnings;
+        if (!RestoreWallet(context, temp_backup_location, wallet_name, /*load_on_start=*/std::nullopt, status, error, warnings)) {
+            error += _("\nUnable to restore backup of wallet.");
+            return util::Error{error};
+        }
+
+        // Move the backup to the wallet dir
+        fs::copy_file(temp_backup_location, backup_path, fs::copy_options::none);
+        fs::remove(temp_backup_location);
+
+        return util::Error{error};
+    }
+    return res;
+}
 } // namespace wallet
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 45391c20d7..d8807dc02d 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -927,6 +927,13 @@ public:
      * May crash if something unexpected happens in the filesystem.
      */
     bool MigrateToSQLite(bilingual_str& error) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
+
+    //! Get all of the descriptors from a legacy wallet
+    std::optional<MigrationData> GetDescriptorsForLegacy(bilingual_str& error) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
+
+    //! Adds the ScriptPubKeyMans given in MigrationData to this wallet, removes LegacyScriptPubKeyMan,
+    //! and where needed, moves tx and address book entries to watchonly_wallet or solvable_wallet
+    bool ApplyMigrationData(MigrationData& data, bilingual_str& error) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 };
 
 /**
@@ -985,6 +992,16 @@ bool RemoveWalletSetting(interfaces::Chain& chain, const std::string& wallet_nam
 bool DummySignInput(const SigningProvider& provider, CTxIn &tx_in, const CTxOut &txout, const CCoinControl* coin_control = nullptr);
 
 bool FillInputToWeight(CTxIn& txin, int64_t target_weight);
+
+struct MigrationResult {
+    std::string wallet_name;
+    std::shared_ptr<CWallet> watchonly_wallet;
+    std::shared_ptr<CWallet> solvables_wallet;
+    fs::path backup_path;
+};
+
+//! Do all steps to migrate a legacy wallet to a descriptor wallet
+util::Result<MigrationResult> MigrateLegacyToDescriptor(std::shared_ptr<CWallet>&& wallet, WalletContext& context);
 } // namespace wallet
 
 #endif // BITCOIN_WALLET_WALLET_H