Bitcoin-Qt: fix crash on Windows caused by CDBEnv::EnvShutdown()

- can be triggerd by just adding -proxy=crashme with 0.7.1
- crash occured, when AppInit2() was left with return false; after the
  first call to bitdb.open() (Step 6 in init)
- this is caused by GetDataDir() or .string() in CDBEnv::EnvShutdown()
  called via the bitdb global destructor
- init fDbEnvInit and fMockDb to false in CDBEnv::CDBEnv()

2 files changed, 6 insertions, 2 deletions

diff --git a/src/db.cpp b/src/db.cpp
index 297240c842..21c3da4cda 100644
--- a/src/db.cpp
+++ b/src/db.cpp
@@ -38,11 +38,13 @@ void CDBEnv::EnvShutdown()
     if (ret != 0)
         printf("EnvShutdown exception: %s (%d)\n", DbEnv::strerror(ret), ret);
     if (!fMockDb)
-        DbEnv(0).remove(GetDataDir().string().c_str(), 0);
+        DbEnv(0).remove(strPath.c_str(), 0);
 }
 
 CDBEnv::CDBEnv() : dbenv(DB_CXX_NO_EXCEPTIONS)
 {
+    fDbEnvInit = false;
+    fMockDb = false;
 }
 
 CDBEnv::~CDBEnv()
@@ -65,6 +67,7 @@ bool CDBEnv::Open(boost::filesystem::path pathEnv_)
 
     pathEnv = pathEnv_;
     filesystem::path pathDataDir = pathEnv;
+    strPath = pathDataDir.string();
     filesystem::path pathLogDir = pathDataDir / "database";
     filesystem::create_directory(pathLogDir);
     filesystem::path pathErrorFile = pathDataDir / "db.log";
@@ -85,7 +88,7 @@ bool CDBEnv::Open(boost::filesystem::path pathEnv_)
     dbenv.set_flags(DB_AUTO_COMMIT, 1);
     dbenv.set_flags(DB_TXN_WRITE_NOSYNC, 1);
     dbenv.log_set_config(DB_LOG_AUTO_REMOVE, 1);
-    int ret = dbenv.open(pathDataDir.string().c_str(),
+    int ret = dbenv.open(strPath.c_str(),
                      DB_CREATE     |
                      DB_INIT_LOCK  |
                      DB_INIT_LOG   |
diff --git a/src/db.h b/src/db.h
index 798913645f..58e9da31f2 100644
--- a/src/db.h
+++ b/src/db.h
@@ -37,6 +37,7 @@ private:
     bool fDbEnvInit;
     bool fMockDb;
     boost::filesystem::path pathEnv;
+    std::string strPath;
 
     void EnvShutdown();