From b42ce5c0de4fa88a8ba4058a7d74425dc9e0178d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Barbosa?= <joao.paulo.barbosa@gmail.com>
Date: Wed, 12 Dec 2018 23:21:19 +0000
Subject: [PATCH] rpc: Make unloadwallet wait for complete wallet unload

Github-Pull: #14941
Rebased-From: c37851d
---
 src/init.cpp          |  1 +
 src/wallet/init.cpp   |  6 ++++++
 src/wallet/wallet.cpp | 23 +++++++++++++++++++++++
 3 files changed, 30 insertions(+)

diff --git a/src/init.cpp b/src/init.cpp
index ccb5962c4..2d320a207 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -286,6 +286,7 @@ void Shutdown(InitInterfaces& interfaces)
         LogPrintf("%s: Unable to remove PID file: %s\n", __func__, fsbridge::get_filesystem_error_message(e));
     }
     interfaces.chain_clients.clear();
+    g_wallet_init_interface.Close();
     UnregisterAllValidationInterfaces();
     GetMainSignals().UnregisterBackgroundSignalScheduler();
     GetMainSignals().UnregisterWithMempoolSignals(mempool);
diff --git a/src/wallet/init.cpp b/src/wallet/init.cpp
index e766deadb..70fbb681a 100644
--- a/src/wallet/init.cpp
+++ b/src/wallet/init.cpp
@@ -135,4 +135,10 @@ void WalletInit::Construct(InitInterfaces& interfaces) const
     }
     gArgs.SoftSetArg("-wallet", "");
     interfaces.chain_clients.emplace_back(interfaces::MakeWalletClient(*interfaces.chain, gArgs.GetArgs("-wallet")));
+    auto wallets = GetWallets();
+    while (!wallets.empty()) {
+        auto wallet = wallets.back();
+        wallets.pop_back();
+        RemoveWallet(wallet);
+        UnloadWallet(std::move(wallet));
 }
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index fdaafd518..946e02130 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -125,6 +125,29 @@ static void ReleaseWallet(CWallet* wallet)
     g_wallet_release_cv.notify_all();
 }
 
+void UnloadWallet(std::shared_ptr<CWallet>&& wallet)
+{
+    // Mark wallet for unloading.
+    CWallet* pwallet = wallet.get();
+    {
+        std::lock_guard<std::mutex> lock(g_wallet_release_mutex);
+        auto it = g_unloading_wallet_set.insert(pwallet);
+        assert(it.second);
+    }
+    // The wallet can be in use so it's not possible to explicitly unload here.
+    // Notify the unload intent so that all remaining shared pointers are
+    // released.
+    pwallet->NotifyUnload();
+    // Time to ditch our shared_ptr and wait for ReleaseWallet call.
+    wallet.reset();
+    {
+        std::unique_lock<std::mutex> lock(g_wallet_release_mutex);
+        while (g_unloading_wallet_set.count(pwallet) == 1) {
+            g_wallet_release_cv.wait(lock);
+        }
+    }
+}
+
 void UnloadWallet(std::shared_ptr<CWallet>&& wallet)
 {
     // Mark wallet for unloading.