Merge #14453: rpc: Fix wallet unload during walletpassphrase timeout

8907df9e02ec47ef249a7422faa766f06aa01e94 qa: Ensure wallet unload during walletpassphrase timeout (João Barbosa)
321decffa1fbf213462d97e5372bd0c4eeb99635 rpc: Fix wallet unload during walletpassphrase timeout (João Barbosa)

Pull request description:

  Replaces the raw wallet pointer in the `RPCRunLater` callback with a `std::weak_ptr` to check if the wallet is not expired.

  To test:
  ```
  bitcoind -regtest
  bitcoin-cli -regtest encryptwallet foobar
  bitcoin-cli -regtest walletpassphrase foobar 5 && bitcoin-cli -regtest unloadwallet ""
  ```

  Fixes #14452.

Tree-SHA512: 311e839234f5fb7955ab5412a2cfc1903ee7132ea56a8ab992ede3614586834886bd65192b76531ae0aa3a526b38e70ca2e1cdbabe52995906ff97b49d93c268

1 files changed, 12 insertions, 8 deletions

diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 5b97ad3ca1..dc39ba3001 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -1803,13 +1803,6 @@ static UniValue keypoolrefill(const JSONRPCRequest& request)
 }
 
 
-static void LockWallet(CWallet* pWallet)
-{
-    LOCK(pWallet->cs_wallet);
-    pWallet->nRelockTime = 0;
-    pWallet->Lock();
-}
-
 static UniValue walletpassphrase(const JSONRPCRequest& request)
 {
     std::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
@@ -1879,7 +1872,18 @@ static UniValue walletpassphrase(const JSONRPCRequest& request)
     pwallet->TopUpKeyPool();
 
     pwallet->nRelockTime = GetTime() + nSleepTime;
-    RPCRunLater(strprintf("lockwallet(%s)", pwallet->GetName()), std::bind(LockWallet, pwallet), nSleepTime);
+
+    // Keep a weak pointer to the wallet so that it is possible to unload the
+    // wallet before the following callback is called. If a valid shared pointer
+    // is acquired in the callback then the wallet is still loaded.
+    std::weak_ptr<CWallet> weak_wallet = wallet;
+    RPCRunLater(strprintf("lockwallet(%s)", pwallet->GetName()), [weak_wallet] {
+        if (auto shared_wallet = weak_wallet.lock()) {
+            LOCK(shared_wallet->cs_wallet);
+            shared_wallet->Lock();
+            shared_wallet->nRelockTime = 0;
+        }
+    }, nSleepTime);
 
     return NullUniValue;
 }