From 0fb78eae34b870b9e5b942095d340f2aae49cd60 Mon Sep 17 00:00:00 2001
From: Jeff Garzik <jgarzik@exmulti.com>
Date: Mon, 14 May 2012 01:11:11 -0400
Subject: [PATCH] Always check return values of TxnBegin() and TxnCommit()

---
 src/bitcoinrpc.cpp |  6 ++++--
 src/main.cpp       | 12 +++++++++---
 src/wallet.cpp     |  3 ++-
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/bitcoinrpc.cpp b/src/bitcoinrpc.cpp
index e058978eb..8e4361c92 100644
--- a/src/bitcoinrpc.cpp
+++ b/src/bitcoinrpc.cpp
@@ -1037,7 +1037,8 @@ Value movecmd(const Array& params, bool fHelp)
         strComment = params[4].get_str();
 
     CWalletDB walletdb(pwalletMain->strWalletFile);
-    walletdb.TxnBegin();
+    if (!walletdb.TxnBegin())
+        throw JSONRPCError(-20, "database error");
 
     int64 nNow = GetAdjustedTime();
 
@@ -1059,7 +1060,8 @@ Value movecmd(const Array& params, bool fHelp)
     credit.strComment = strComment;
     walletdb.WriteAccountingEntry(credit);
 
-    walletdb.TxnCommit();
+    if (!walletdb.TxnCommit())
+        throw JSONRPCError(-20, "database error");
 
     return true;
 }
diff --git a/src/main.cpp b/src/main.cpp
index 20bb56e96..870a8ef61 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1514,7 +1514,9 @@ bool CBlock::SetBestChain(CTxDB& txdb, CBlockIndex* pindexNew)
 {
     uint256 hash = GetHash();
 
-    txdb.TxnBegin();
+    if (!txdb.TxnBegin())
+        return error("SetBestChain() : TxnBegin failed");
+
     if (pindexGenesisBlock == NULL && hash == hashGenesisBlock)
     {
         txdb.WriteHashBestChain(hash);
@@ -1563,7 +1565,10 @@ bool CBlock::SetBestChain(CTxDB& txdb, CBlockIndex* pindexNew)
                 printf("SetBestChain() : ReadFromDisk failed\n");
                 break;
             }
-            txdb.TxnBegin();
+            if (!txdb.TxnBegin()) {
+                printf("SetBestChain() : TxnBegin 2 failed\n");
+                break;
+            }
             // errors now are not fatal, we still did a reorganisation to a new chain in a valid way
             if (!block.SetBestChainInner(txdb, pindex))
                 break;
@@ -1621,7 +1626,8 @@ bool CBlock::AddToBlockIndex(unsigned int nFile, unsigned int nBlockPos)
     pindexNew->bnChainWork = (pindexNew->pprev ? pindexNew->pprev->bnChainWork : 0) + pindexNew->GetBlockWork();
 
     CTxDB txdb;
-    txdb.TxnBegin();
+    if (!txdb.TxnBegin())
+        return false;
     txdb.WriteBlockIndex(CDiskBlockIndex(pindexNew));
     if (!txdb.TxnCommit())
         return false;
diff --git a/src/wallet.cpp b/src/wallet.cpp
index 998909897..96dc986ed 100644
--- a/src/wallet.cpp
+++ b/src/wallet.cpp
@@ -242,7 +242,8 @@ bool CWallet::EncryptWallet(const SecureString& strWalletPassphrase)
         if (fFileBacked)
         {
             pwalletdbEncryption = new CWalletDB(strWalletFile);
-            pwalletdbEncryption->TxnBegin();
+            if (!pwalletdbEncryption->TxnBegin())
+                return false;
             pwalletdbEncryption->WriteMasterKey(nMasterKeyMaxID, kMasterKey);
         }