Handle incompatible BDB environments

Before, opening a -datadir that was created with a new
version of Berkeley DB would result in an un-caught DB_RUNRECOVERY
exception.

After these changes, the error is caught and the user is told
that there is a problem and is told how to try to recover from
it.

Reference: bitcoin/bitcoin#1917

Author: IngCr3at1on

src/db.cpp

@@ -37,19 +37,15 @@ void CDBEnv::EnvShutdown()
         return;
 
     fDbEnvInit = false;
-    try
-    {
-        dbenv.close(0);
-    }
-    catch (const DbException& e)
-    {
-        printf("EnvShutdown exception: %s (%d)\n", e.what(), e.get_errno());
-    }
+    int ret = dbenv.close(0);
+    if (ret != 0)
+        printf("EnvShutdown exception: %s (%d)\n", DbEnv::strerror(ret), ret);
+
     if (!fMockDb)
         DbEnv(0).remove(GetDataDir().string().c_str(), 0);
 }
 
-CDBEnv::CDBEnv() : dbenv(0)
+CDBEnv::CDBEnv() : dbenv(DB_CXX_NO_EXCEPTIONS)
 {
 }
 
@@ -96,8 +92,8 @@ bool CDBEnv::Open(const boost::filesystem::path& path)
                      DB_THREAD     |
                      DB_RECOVER,
                      S_IRUSR | S_IWUSR);
-    if (ret > 0)
-        return error("CDB() : error %d opening database environment", ret);
+    if (ret != 0)
+        return error("CDB() : error %s (%d) opening database environment", DbEnv::strerror(ret), ret);
 
     fDbEnvInit = true;
     fMockDb = false;
@@ -186,7 +182,7 @@ CDB::CDB(const char *pszFile, const char* pszMode) :
                             nFlags,    // Flags
                             0);
 
-            if (ret > 0)
+            if (ret != 0)
             {
                 delete pdb;
                 pdb = NULL;

src/init.cpp

@@ -428,8 +428,11 @@ bool AppInit2()
     FILE* file = fopen(pathLockFile.string().c_str(), "a"); // empty lock file; created if it doesn't exist.
     if (file) fclose(file);
     static boost::interprocess::file_lock lock(pathLockFile.string().c_str());
+    /* Set a cstring to hold the datadir path cause we use it several times
+     * throughout init. */
+    const char* pszDataDir = GetDataDir().string().c_str();
     if (!lock.try_lock())
-        return InitError(strprintf(_("Cannot obtain a lock on data directory %s.  Paycoin is probably already running."), GetDataDir().string().c_str()));
+        return InitError(strprintf(_("Cannot obtain a lock on data directory %s.  Paycoin is probably already running."), pszDataDir));
 
 #if !defined(WIN32) && !defined(QT_GUI)
     if (fDaemon)
@@ -459,7 +462,7 @@ bool AppInit2()
     printf("Paycoin version %s (%s)\n", FormatFullVersion().c_str(), CLIENT_DATE.c_str());
     printf("Using OpenSSL version %s\n", SSLeay_version(SSLEAY_VERSION));
     printf("Default data directory %s\n", GetDefaultDataDir().string().c_str());
-    printf("Used data directory %s\n", GetDataDir().string().c_str());
+    printf("Used data directory %s\n", pszDataDir);
 
     // Check and update minium version protocol after a given time.
     if (time(NULL) >= MICROPRIMES_STAGGER_DOWN)
@@ -471,6 +474,15 @@ bool AppInit2()
     //
     if (fDaemon)
         fprintf(stdout, "Paycoin server starting\n");
+
+    if (!bitdb.Open(GetDataDir()))
+    {
+        string msg = strprintf(_("Error initializing database environment %s!"
+                                 " To recover, BACKUP THAT DIRECTORY, then remove"
+                                 " everything from it except for wallet.dat."), pszDataDir);
+        return InitError(msg);
+    }
+
     int64 nStart;
 
     // ********************************************************* Step 5: network initialization
@@ -582,7 +594,7 @@ bool AppInit2()
     printf("Loading block index...\n");
     nStart = GetTimeMillis();
     if (!LoadBlockIndex())
-        strErrors << _("Error loading blkindex.dat") << "\n";
+        return InitError(_("Error loading blkindex.dat"));
 
     // as LoadBlockIndex can take several minutes, it's possible the user
     // requested to kill bitcoin-qt during the last operation. If so, exit.