db: recreate Berkeley DB environment after shutdown

4 files changed, 130 insertions, 36 deletions

diff --git a/src/db.cpp b/src/db.cpp
index 0ff58e7..8b82fe5 100644
--- a/src/db.cpp
+++ b/src/db.cpp
@@ -52,9 +52,34 @@ static bool fDbEnvInit = false;
 // Why LoadWallet() refused, in words meant for the person who has to act on it.
 // Empty unless the reason is one we can name.
 string strWalletLoadError;
-DbEnv dbenv(0u);
+static DbEnv* pdbenv = NULL;
+static FILE* pdbErrFile = NULL;
 static map<string, int> mapFileUseCount;
 
+DbEnv& GetDbEnv()
+{
+    if (!pdbenv)
+        pdbenv = new DbEnv(0u);
+    return *pdbenv;
+}
+
+static void CloseDbEnv()
+{
+    if (pdbenv)
+    {
+        try { pdbenv->close(0); }
+        catch (...) { }
+        delete pdbenv;
+        pdbenv = NULL;
+    }
+    if (pdbErrFile)
+    {
+        fclose(pdbErrFile);
+        pdbErrFile = NULL;
+    }
+    fDbEnvInit = false;
+}
+
 class CDBInit
 {
 public:
@@ -64,11 +89,7 @@ public:
     ~CDBInit()
     {
         if (fDbEnvInit)
-        {
-            try { dbenv.close(0); }
-            catch (...) { }
-            fDbEnvInit = false;
-        }
+            CloseDbEnv();
     }
 }
 instance_of_cdbinit;
@@ -104,24 +125,30 @@ CDB::CDB(const char* pszFile, const char* pszMode, bool fTxn) : pdb(NULL)
 
             printf("dbenv.open strAppDir=%s\n", strAppDir.c_str());
 
-            dbenv.set_lg_dir(strLogDir.c_str());
-            dbenv.set_lg_max(10000000);
-            dbenv.set_lk_max_locks(10000);
-            dbenv.set_lk_max_objects(10000);
-            dbenv.set_errfile(fopen("db.log", "a")); /// debug
-            ///dbenv.log_set_config(DB_LOG_AUTO_REMOVE, 1); /// causes corruption
-            ret = dbenv.open(strAppDir.c_str(),
-                             DB_CREATE     |
-                             DB_INIT_LOCK  |
-                             DB_INIT_LOG   |
-                             DB_INIT_MPOOL |
-                             DB_INIT_TXN   |
-                             DB_THREAD     |
-                             DB_PRIVATE    |
-                             DB_RECOVER,
-                             0);
+            DbEnv& env = GetDbEnv();
+            env.set_lg_dir(strLogDir.c_str());
+            env.set_lg_max(10000000);
+            env.set_lk_max_locks(10000);
+            env.set_lk_max_objects(10000);
+            pdbErrFile = fopen("db.log", "a"); /// debug
+            if (pdbErrFile)
+                env.set_errfile(pdbErrFile);
+            ///env.log_set_config(DB_LOG_AUTO_REMOVE, 1); /// causes corruption
+            ret = env.open(strAppDir.c_str(),
+                           DB_CREATE     |
+                           DB_INIT_LOCK  |
+                           DB_INIT_LOG   |
+                           DB_INIT_MPOOL |
+                           DB_INIT_TXN   |
+                           DB_THREAD     |
+                           DB_PRIVATE    |
+                           DB_RECOVER,
+                           0);
             if (ret > 0)
+            {
+                CloseDbEnv();
                 throw runtime_error(strprintf("CDB() : error %d opening database environment\n", ret));
+            }
             fDbEnvInit = true;
 
             // A Berkeley DB file records, in every page header, a log sequence
@@ -151,7 +178,7 @@ CDB::CDB(const char* pszFile, const char* pszMode, bool fTxn) : pdb(NULL)
                         continue;
                     try
                     {
-                        if (dbenv.lsn_reset(pszName, 0) == 0)
+                        if (env.lsn_reset(pszName, 0) == 0)
                             printf("CDB() : adopted %s from another environment "
                                    "(log sequence numbers reset)\n", pszName);
                     }
@@ -164,7 +191,7 @@ CDB::CDB(const char* pszFile, const char* pszMode, bool fTxn) : pdb(NULL)
         ++mapFileUseCount[strFile];
     }
 
-    pdb = new Db(&dbenv, 0);
+    pdb = new Db(&GetDbEnv(), 0);
 
     ret = pdb->open(NULL,      // Txn pointer
                     pszFile,   // Filename
@@ -199,7 +226,8 @@ void CDB::Close()
     try { pdb->close(0); } catch (...) { }
     delete pdb;
     pdb = NULL;
-    try { dbenv.txn_checkpoint(0, 0, 0); } catch (...) { }
+    if (fDbEnvInit)
+        try { GetDbEnv().txn_checkpoint(0, 0, 0); } catch (...) { }
 
     CRITICAL_BLOCK(cs_db)
         --mapFileUseCount[strFile];
@@ -279,7 +307,8 @@ void DBFlush(bool fShutdown)
         // takes the process down before the wallet has been put down cleanly,
         // which is the difference between a portable wallet.dat and one welded
         // to this directory -- the lsn_reset just below is what frees it.
-        try { dbenv.txn_checkpoint(0, 0, 0); }
+        DbEnv& env = GetDbEnv();
+        try { env.txn_checkpoint(0, 0, 0); }
         catch (const std::exception& e)
         { printf("DBFlush() : checkpoint failed: %s\n", e.what()); }
 
@@ -290,7 +319,7 @@ void DBFlush(bool fShutdown)
             int nRefCount = (*mi).second;
             if (nRefCount == 0)
             {
-                try { dbenv.lsn_reset(strFile.c_str(), 0); }
+                try { env.lsn_reset(strFile.c_str(), 0); }
                 catch (const std::exception& e)
                 { printf("DBFlush() : lsn_reset(%s) failed: %s\n", strFile.c_str(), e.what()); }
                 mapFileUseCount.erase(mi++);
@@ -310,9 +339,8 @@ void DBFlush(bool fShutdown)
             // Found while making wallet encryption clean up after itself:
             // calling DBFlush(true) a second time crashed here every time.
             if (mapFileUseCount.empty())
-                try { dbenv.log_archive(NULL, DB_ARCH_REMOVE); } catch (...) { }
-            try { dbenv.close(0); } catch (...) { }
-            fDbEnvInit = false;
+                try { env.log_archive(NULL, DB_ARCH_REMOVE); } catch (...) { }
+            CloseDbEnv();
         }
     }
 }
@@ -1042,7 +1070,8 @@ bool BackupWallet(const string& strDest)
         // Committing first, so the copy is not missing the newest records.
         // Both calls can throw, and a failed backup must not take the node
         // down with it.
-        try { dbenv.txn_checkpoint(0, 0, 0); }
+        DbEnv& env = GetDbEnv();
+        try { env.txn_checkpoint(0, 0, 0); }
         catch (const std::exception& e)
         { return error("BackupWallet() : checkpoint failed: %s\n", e.what()); }
 
@@ -1077,7 +1106,7 @@ bool BackupWallet(const string& strDest)
             }
 
             // Without this the copy is welded to this node's database/ dir.
-            int ret = dbenv.lsn_reset(strTemp.c_str(), 0);
+            int ret = env.lsn_reset(strTemp.c_str(), 0);
             if (ret != 0)
                 printf("BackupWallet() : warning -- lsn_reset returned %d; the copy "
                        "may only open beside this node's database/ directory\n", ret);
diff --git a/src/db.h b/src/db.h
index 2816957..53bda59 100644
--- a/src/db.h
+++ b/src/db.h
@@ -48,7 +48,7 @@ public:
 };
 
 
-extern DbEnv dbenv;
+extern DbEnv& GetDbEnv();
 extern void DBFlush(bool fShutdown);
 // Close the environment and delete its logs. Only the encryption command calls
 // this: the logs hold the plaintext records the old wallet wrote.
@@ -237,7 +237,7 @@ public:
         if (!pdb)
             return false;
         DbTxn* ptxn = NULL;
-        int ret = dbenv.txn_begin(GetTxn(), &ptxn, 0);
+        int ret = GetDbEnv().txn_begin(GetTxn(), &ptxn, 0);
         if (!ptxn || ret != 0)
             return false;
         vTxn.push_back(ptxn);
diff --git a/src/main_gui.cpp b/src/main_gui.cpp
index feda428..705b4ef 100644
--- a/src/main_gui.cpp
+++ b/src/main_gui.cpp
@@ -114,7 +114,8 @@ static void PrintUsage()
     printf("  /gen\n");
     printf("  /nogui or /daemon\n");
     printf("  /selftest=wallet-keypool, wallet-hd, wallet-format, wallet-storage-sanity,\n");
-    printf("            wallet-crypto, wallet-encrypt, wallet-portability, net-message,\n");
+    printf("            db-env-reopen, wallet-crypto, wallet-encrypt, wallet-portability,\n");
+    printf("            net-message,\n");
     printf("            consensus-limits, pool-stratum,\n");
     printf("            parse-money, socks5-proxy, or managed-tor\n");
     printf("\n");
diff --git a/src/selftest.cpp b/src/selftest.cpp
index 54249b1..31c168f 100644
--- a/src/selftest.cpp
+++ b/src/selftest.cpp
@@ -968,6 +968,68 @@ static int RunWalletStorageSanitySelfTest()
     return nFail == 0 ? 0 : 1;
 }
 
+static int RunDbEnvReopenSelfTest()
+{
+    fflush(stdout);
+    printf("db-env-reopen self-test\n");
+
+    std::string tmp;
+    if (!MakeTempDir(tmp))
+    {
+        printf("  FAIL could not create a temporary data directory\n");
+        return 1;
+    }
+
+    int nFail = 0;
+    std::string strOldDataDir = strSetDataDir;
+    strSetDataDir = tmp;
+    printf("  temp datadir: %s\n", tmp.c_str());
+
+    try
+    {
+        for (int i = 0; i < 5; i++)
+        {
+            int64 nValue = 1000 + i;
+            {
+                CWalletDB walletdb("cr+");
+                nFail += Check(walletdb.WriteSetting("db-env-reopen-cycle", nValue),
+                               "wallet setting can be written before shutdown") ? 0 : 1;
+            }
+
+            DBFlush(true);
+
+            int64 nRead = 0;
+            {
+                CWalletDB walletdb("r");
+                nFail += Check(walletdb.ReadSetting("db-env-reopen-cycle", nRead),
+                               "wallet setting can be read after env reopen") ? 0 : 1;
+            }
+            nFail += Check(nRead == nValue,
+                           "reopened environment reads the last committed value") ? 0 : 1;
+
+            DBFlush(true);
+        }
+    }
+    catch (const std::exception& e)
+    {
+        printf("  FAIL exception: %s\n", e.what());
+        nFail++;
+    }
+    catch (...)
+    {
+        printf("  FAIL unknown exception\n");
+        nFail++;
+    }
+
+    DBFlush(true);
+    strSetDataDir = strOldDataDir;
+    RemoveTree(tmp);
+    printf("%s (%d failure%s)\n", nFail == 0 ? "ALL TESTS PASSED" : "TESTS FAILED",
+           nFail, nFail == 1 ? "" : "s");
+    fflush(stdout);
+    return nFail == 0 ? 0 : 1;
+}
+
 static void ClearWalletRuntimeForTest()
 {
     CRITICAL_BLOCK(cs_mapKeys)
@@ -2225,6 +2287,8 @@ int RunSelfTest(const std::string& name)
         return RunWalletFormatSelfTest();
     if (name == "wallet-storage-sanity")
         return RunWalletStorageSanitySelfTest();
+    if (name == "db-env-reopen")
+        return RunDbEnvReopenSelfTest();
     if (name == "wallet-crypto")
         return RunWalletCryptoSelfTest();
     if (name == "wallet-encrypt")
@@ -2245,6 +2309,6 @@ int RunSelfTest(const std::string& name)
         return RunManagedTorSelfTest();
 
     printf("Unknown self-test '%s'\n", name.c_str());
-    printf("Known self-tests: wallet-keypool, wallet-hd, wallet-format, wallet-storage-sanity, wallet-crypto, wallet-encrypt, wallet-portability, net-message, consensus-limits, pool-stratum, parse-money, socks5-proxy, managed-tor\n");
+    printf("Known self-tests: wallet-keypool, wallet-hd, wallet-format, wallet-storage-sanity, db-env-reopen, wallet-crypto, wallet-encrypt, wallet-portability, net-message, consensus-limits, pool-stratum, parse-money, socks5-proxy, managed-tor\n");
     return 1;
 }