From c87770915b88d195d264b58111c64142b1965cfa Mon Sep 17 00:00:00 2001
From: Andrew Chow <achow101-github@achow101.com>
Date: Fri, 8 May 2020 17:06:16 -0400
Subject: wallettool: Add a salvage command

---
 src/bitcoin-wallet.cpp    |  1 +
 src/wallet/wallettool.cpp | 38 +++++++++++++++++++++++++++++++++-----
 2 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/src/bitcoin-wallet.cpp b/src/bitcoin-wallet.cpp
index 7f9439788a..b420463c00 100644
--- a/src/bitcoin-wallet.cpp
+++ b/src/bitcoin-wallet.cpp
@@ -31,6 +31,7 @@ static void SetupWalletToolArgs()
 
     gArgs.AddArg("info", "Get wallet info", ArgsManager::ALLOW_ANY, OptionsCategory::COMMANDS);
     gArgs.AddArg("create", "Create new wallet file", ArgsManager::ALLOW_ANY, OptionsCategory::COMMANDS);
+    gArgs.AddArg("salvage", "Attempt to recover private keys from a corrupt wallet", ArgsManager::ALLOW_ANY, OptionsCategory::COMMANDS);
 }
 
 static bool WalletAppInit(int argc, char* argv[])
diff --git a/src/wallet/wallettool.cpp b/src/wallet/wallettool.cpp
index 522efaa884..89645fb5cd 100644
--- a/src/wallet/wallettool.cpp
+++ b/src/wallet/wallettool.cpp
@@ -103,6 +103,29 @@ static void WalletShowInfo(CWallet* wallet_instance)
     tfm::format(std::cout, "Address Book: %zu\n", wallet_instance->m_address_book.size());
 }
 
+static bool SalvageWallet(const fs::path& path)
+{
+    // Create a Database handle to allow for the db to be initialized before recovery
+    std::unique_ptr<WalletDatabase> database = WalletDatabase::Create(path);
+
+    // Initialize the environment before recovery
+    bilingual_str error_string;
+    try {
+        WalletBatch::VerifyEnvironment(path, error_string);
+    } catch (const fs::filesystem_error& e) {
+        error_string = Untranslated(strprintf("Error loading wallet. %s", fsbridge::get_filesystem_error_message(e)));
+    }
+    if (!error_string.original.empty()) {
+        tfm::format(std::cerr, "Failed to open wallet for salvage :%s\n", error_string.original);
+        return false;
+    }
+
+    // Perform the recovery
+    CWallet dummy_wallet(nullptr, WalletLocation(), WalletDatabase::CreateDummy());
+    std::string backup_filename;
+    return WalletBatch::Recover(path, (void*)&dummy_wallet, WalletBatch::RecoverKeysOnlyFilter, backup_filename);
+}
+
 bool ExecuteWalletToolFunc(const std::string& command, const std::string& name)
 {
     fs::path path = fs::absolute(name, GetWalletDir());
@@ -113,7 +136,7 @@ bool ExecuteWalletToolFunc(const std::string& command, const std::string& name)
             WalletShowInfo(wallet_instance.get());
             wallet_instance->Flush(true);
         }
-    } else if (command == "info") {
+    } else if (command == "info" || command == "salvage") {
         if (!fs::exists(path)) {
             tfm::format(std::cerr, "Error: no wallet file at %s\n", name);
             return false;
@@ -123,10 +146,15 @@ bool ExecuteWalletToolFunc(const std::string& command, const std::string& name)
             tfm::format(std::cerr, "%s\nError loading %s. Is wallet being used by other process?\n", error.original, name);
             return false;
         }
-        std::shared_ptr<CWallet> wallet_instance = LoadWallet(name, path);
-        if (!wallet_instance) return false;
-        WalletShowInfo(wallet_instance.get());
-        wallet_instance->Flush(true);
+
+        if (command == "info") {
+            std::shared_ptr<CWallet> wallet_instance = LoadWallet(name, path);
+            if (!wallet_instance) return false;
+            WalletShowInfo(wallet_instance.get());
+            wallet_instance->Flush(true);
+        } else if (command == "salvage") {
+            return SalvageWallet(path);
+        }
     } else {
         tfm::format(std::cerr, "Invalid command: %s\n", command);
         return false;
-- 
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