Move RecoverDatabaseFile and RecoverKeysOnlyFilter into salvage.{cpp/h}

1 files changed, 160 insertions, 0 deletions

diff --git a/src/wallet/salvage.cpp b/src/wallet/salvage.cpp
new file mode 100644
index 0000000000..99d6238490
--- /dev/null
+++ b/src/wallet/salvage.cpp
@@ -0,0 +1,160 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <fs.h>
+#include <streams.h>
+#include <wallet/salvage.h>
+#include <wallet/wallet.h>
+#include <wallet/walletdb.h>
+
+/* End of headers, beginning of key/value data */
+static const char *HEADER_END = "HEADER=END";
+/* End of key/value data */
+static const char *DATA_END = "DATA=END";
+typedef std::pair<std::vector<unsigned char>, std::vector<unsigned char> > KeyValPair;
+
+bool RecoverDatabaseFile(const fs::path& file_path, void *callbackDataIn, bool (*recoverKVcallback)(void* callbackData, CDataStream ssKey, CDataStream ssValue), std::string& newFilename)
+{
+    std::string filename;
+    std::shared_ptr<BerkeleyEnvironment> env = GetWalletEnv(file_path, filename);
+
+    // Recovery procedure:
+    // move wallet file to walletfilename.timestamp.bak
+    // Call Salvage with fAggressive=true to
+    // get as much data as possible.
+    // Rewrite salvaged data to fresh wallet file
+    // Set -rescan so any missing transactions will be
+    // found.
+    int64_t now = GetTime();
+    newFilename = strprintf("%s.%d.bak", filename, now);
+
+    int result = env->dbenv->dbrename(nullptr, filename.c_str(), nullptr,
+                                       newFilename.c_str(), DB_AUTO_COMMIT);
+    if (result == 0)
+        LogPrintf("Renamed %s to %s\n", filename, newFilename);
+    else
+    {
+        LogPrintf("Failed to rename %s to %s\n", filename, newFilename);
+        return false;
+    }
+
+    /**
+     * Salvage data from a file. The DB_AGGRESSIVE flag is being used (see berkeley DB->verify() method documentation).
+     * key/value pairs are appended to salvagedData which are then written out to a new wallet file.
+     * NOTE: reads the entire database into memory, so cannot be used
+     * for huge databases.
+     */
+    std::vector<KeyValPair> salvagedData;
+
+    std::stringstream strDump;
+
+    Db db(env->dbenv.get(), 0);
+    result = db.verify(newFilename.c_str(), nullptr, &strDump, DB_SALVAGE | DB_AGGRESSIVE);
+    if (result == DB_VERIFY_BAD) {
+        LogPrintf("Salvage: Database salvage found errors, all data may not be recoverable.\n");
+    }
+    if (result != 0 && result != DB_VERIFY_BAD) {
+        LogPrintf("Salvage: Database salvage failed with result %d.\n", result);
+        return false;
+    }
+
+    // Format of bdb dump is ascii lines:
+    // header lines...
+    // HEADER=END
+    //  hexadecimal key
+    //  hexadecimal value
+    //  ... repeated
+    // DATA=END
+
+    std::string strLine;
+    while (!strDump.eof() && strLine != HEADER_END)
+        getline(strDump, strLine); // Skip past header
+
+    std::string keyHex, valueHex;
+    while (!strDump.eof() && keyHex != DATA_END) {
+        getline(strDump, keyHex);
+        if (keyHex != DATA_END) {
+            if (strDump.eof())
+                break;
+            getline(strDump, valueHex);
+            if (valueHex == DATA_END) {
+                LogPrintf("Salvage: WARNING: Number of keys in data does not match number of values.\n");
+                break;
+            }
+            salvagedData.push_back(make_pair(ParseHex(keyHex), ParseHex(valueHex)));
+        }
+    }
+
+    bool fSuccess;
+    if (keyHex != DATA_END) {
+        LogPrintf("Salvage: WARNING: Unexpected end of file while reading salvage output.\n");
+        fSuccess = false;
+    } else {
+        fSuccess = (result == 0);
+    }
+
+    if (salvagedData.empty())
+    {
+        LogPrintf("Salvage(aggressive) found no records in %s.\n", newFilename);
+        return false;
+    }
+    LogPrintf("Salvage(aggressive) found %u records\n", salvagedData.size());
+
+    std::unique_ptr<Db> pdbCopy = MakeUnique<Db>(env->dbenv.get(), 0);
+    int ret = pdbCopy->open(nullptr,               // Txn pointer
+                            filename.c_str(),   // Filename
+                            "main",             // Logical db name
+                            DB_BTREE,           // Database type
+                            DB_CREATE,          // Flags
+                            0);
+    if (ret > 0) {
+        LogPrintf("Cannot create database file %s\n", filename);
+        pdbCopy->close(0);
+        return false;
+    }
+
+    DbTxn* ptxn = env->TxnBegin();
+    for (KeyValPair& row : salvagedData)
+    {
+        if (recoverKVcallback)
+        {
+            CDataStream ssKey(row.first, SER_DISK, CLIENT_VERSION);
+            CDataStream ssValue(row.second, SER_DISK, CLIENT_VERSION);
+            if (!(*recoverKVcallback)(callbackDataIn, ssKey, ssValue))
+                continue;
+        }
+        Dbt datKey(&row.first[0], row.first.size());
+        Dbt datValue(&row.second[0], row.second.size());
+        int ret2 = pdbCopy->put(ptxn, &datKey, &datValue, DB_NOOVERWRITE);
+        if (ret2 > 0)
+            fSuccess = false;
+    }
+    ptxn->commit(0);
+    pdbCopy->close(0);
+
+    return fSuccess;
+}
+
+bool RecoverKeysOnlyFilter(void *callbackData, CDataStream ssKey, CDataStream ssValue)
+{
+    CWallet *dummyWallet = reinterpret_cast<CWallet*>(callbackData);
+    std::string strType, strErr;
+    bool fReadOK;
+    {
+        // Required in LoadKeyMetadata():
+        LOCK(dummyWallet->cs_wallet);
+        fReadOK = ReadKeyValue(dummyWallet, ssKey, ssValue, strType, strErr);
+    }
+    if (!WalletBatch::IsKeyType(strType) && strType != DBKeys::HDCHAIN) {
+        return false;
+    }
+    if (!fReadOK)
+    {
+        LogPrintf("WARNING: WalletBatch::Recover skipping %s: %s\n", strType, strErr);
+        return false;
+    }
+
+    return true;
+}