src/dbwrapper.cpp

   1 // Copyright (c) 2012-2016 The Bitcoin Core developers
   2 // Distributed under the MIT software license, see the accompanying
   3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   4
   5 #include "dbwrapper.h"
   6
   7 #include "fs.h"
   8 #include "util.h"
   9 #include "random.h"
  10
  11 #include <leveldb/cache.h>
  12 #include <leveldb/env.h>
  13 #include <leveldb/filter_policy.h>
  14 #include <memenv.h>
  15 #include <stdint.h>
  16 #include <algorithm>
  17
  18 class CBitcoinLevelDBLogger : public leveldb::Logger {
  19 public:
  20     // This code is adapted from posix_logger.h, which is why it is using vsprintf.
  21     // Please do not do this in normal code
  22     virtual void Logv(const char * format, va_list ap) override {
  23             if (!LogAcceptCategory(BCLog::LEVELDB)) {
  24                 return;
  25             }
  26             char buffer[500];
  27             for (int iter = 0; iter < 2; iter++) {
  28                 char* base;
  29                 int bufsize;
  30                 if (iter == 0) {
  31                     bufsize = sizeof(buffer);
  32                     base = buffer;
  33                 }
  34                 else {
  35                     bufsize = 30000;
  36                     base = new char[bufsize];
  37                 }
  38                 char* p = base;
  39                 char* limit = base + bufsize;
  40
  41                 // Print the message
  42                 if (p < limit) {
  43                     va_list backup_ap;
  44                     va_copy(backup_ap, ap);
  45                     // Do not use vsnprintf elsewhere in bitcoin source code, see above.
  46                     p += vsnprintf(p, limit - p, format, backup_ap);
  47                     va_end(backup_ap);
  48                 }
  49
  50                 // Truncate to available space if necessary
  51                 if (p >= limit) {
  52                     if (iter == 0) {
  53                         continue;       // Try again with larger buffer
  54                     }
  55                     else {
  56                         p = limit - 1;
  57                     }
  58                 }
  59
  60                 // Add newline if necessary
  61                 if (p == base || p[-1] != '\n') {
  62                     *p++ = '\n';
  63                 }
  64
  65                 assert(p <= limit);
  66                 base[std::min(bufsize - 1, (int)(p - base))] = '\0';
  67                 LogPrintStr(base);
  68                 if (base != buffer) {
  69                     delete[] base;
  70                 }
  71                 break;
  72             }
  73     }
  74 };
  75
  76 static leveldb::Options GetOptions(size_t nCacheSize)
  77 {
  78     leveldb::Options options;
  79     options.block_cache = leveldb::NewLRUCache(nCacheSize / 2);
  80     options.write_buffer_size = nCacheSize / 4; // up to two write buffers may be held in memory simultaneously
  81     options.filter_policy = leveldb::NewBloomFilterPolicy(10);
  82     options.compression = leveldb::kNoCompression;
  83     options.max_open_files = 64;
  84     options.info_log = new CBitcoinLevelDBLogger();
  85     if (leveldb::kMajorVersion > 1 || (leveldb::kMajorVersion == 1 && leveldb::kMinorVersion >= 16)) {
  86         // LevelDB versions before 1.16 consider short writes to be corruption. Only trigger error
  87         // on corruption in later versions.
  88         options.paranoid_checks = true;
  89     }
  90     return options;
  91 }
  92
  93 CDBWrapper::CDBWrapper(const fs::path& path, size_t nCacheSize, bool fMemory, bool fWipe, bool obfuscate)
  94 {
  95     penv = NULL;
  96     readoptions.verify_checksums = true;
  97     iteroptions.verify_checksums = true;
  98     iteroptions.fill_cache = false;
  99     syncoptions.sync = true;
 100     options = GetOptions(nCacheSize);
 101     options.create_if_missing = true;
 102     if (fMemory) {
 103         penv = leveldb::NewMemEnv(leveldb::Env::Default());
 104         options.env = penv;
 105     } else {
 106         if (fWipe) {
 107             LogPrintf("Wiping LevelDB in %s\n", path.string());
 108             leveldb::Status result = leveldb::DestroyDB(path.string(), options);
 109             dbwrapper_private::HandleError(result);
 110         }
 111         TryCreateDirectories(path);
 112         LogPrintf("Opening LevelDB in %s\n", path.string());
 113     }
 114     leveldb::Status status = leveldb::DB::Open(options, path.string(), &pdb);
 115     dbwrapper_private::HandleError(status);
 116     LogPrintf("Opened LevelDB successfully\n");
 117
 118     // The base-case obfuscation key, which is a noop.
 119     obfuscate_key = std::vector<unsigned char>(OBFUSCATE_KEY_NUM_BYTES, '\000');
 120
 121     bool key_exists = Read(OBFUSCATE_KEY_KEY, obfuscate_key);
 122
 123     if (!key_exists && obfuscate && IsEmpty()) {
 124         // Initialize non-degenerate obfuscation if it won't upset
 125         // existing, non-obfuscated data.
 126         std::vector<unsigned char> new_key = CreateObfuscateKey();
 127
 128         // Write `new_key` so we don't obfuscate the key with itself
 129         Write(OBFUSCATE_KEY_KEY, new_key);
 130         obfuscate_key = new_key;
 131
 132         LogPrintf("Wrote new obfuscate key for %s: %s\n", path.string(), HexStr(obfuscate_key));
 133     }
 134
 135     LogPrintf("Using obfuscation key for %s: %s\n", path.string(), HexStr(obfuscate_key));
 136 }
 137
 138 CDBWrapper::~CDBWrapper()
 139 {
 140     delete pdb;
 141     pdb = NULL;
 142     delete options.filter_policy;
 143     options.filter_policy = NULL;
 144     delete options.info_log;
 145     options.info_log = NULL;
 146     delete options.block_cache;
 147     options.block_cache = NULL;
 148     delete penv;
 149     options.env = NULL;
 150 }
 151
 152 bool CDBWrapper::WriteBatch(CDBBatch& batch, bool fSync)
 153 {
 154     leveldb::Status status = pdb->Write(fSync ? syncoptions : writeoptions, &batch.batch);
 155     dbwrapper_private::HandleError(status);
 156     return true;
 157 }
 158
 159 // Prefixed with null character to avoid collisions with other keys
 160 //
 161 // We must use a string constructor which specifies length so that we copy
 162 // past the null-terminator.
 163 const std::string CDBWrapper::OBFUSCATE_KEY_KEY("\000obfuscate_key", 14);
 164
 165 const unsigned int CDBWrapper::OBFUSCATE_KEY_NUM_BYTES = 8;
 166
 167 /**
 168  * Returns a string (consisting of 8 random bytes) suitable for use as an
 169  * obfuscating XOR key.
 170  */
 171 std::vector<unsigned char> CDBWrapper::CreateObfuscateKey() const
 172 {
 173     unsigned char buff[OBFUSCATE_KEY_NUM_BYTES];
 174     GetRandBytes(buff, OBFUSCATE_KEY_NUM_BYTES);
 175     return std::vector<unsigned char>(&buff[0], &buff[OBFUSCATE_KEY_NUM_BYTES]);
 176
 177 }
 178
 179 bool CDBWrapper::IsEmpty()
 180 {
 181     std::unique_ptr<CDBIterator> it(NewIterator());
 182     it->SeekToFirst();
 183     return !(it->Valid());
 184 }
 185
 186 CDBIterator::~CDBIterator() { delete piter; }
 187 bool CDBIterator::Valid() { return piter->Valid(); }
 188 void CDBIterator::SeekToFirst() { piter->SeekToFirst(); }
 189 void CDBIterator::Next() { piter->Next(); }
 190
 191 namespace dbwrapper_private {
 192
 193 void HandleError(const leveldb::Status& status)
 194 {
 195     if (status.ok())
 196         return;
 197     LogPrintf("%s\n", status.ToString());
 198     if (status.IsCorruption())
 199         throw dbwrapper_error("Database corrupted");
 200     if (status.IsIOError())
 201         throw dbwrapper_error("Database I/O error");
 202     if (status.IsNotFound())
 203         throw dbwrapper_error("Database entry missing");
 204     throw dbwrapper_error("Unknown database error");
 205 }
 206
 207 const std::vector<unsigned char>& GetObfuscateKey(const CDBWrapper &w)
 208 {
 209     return w.obfuscate_key;
 210 }
 211
 212 } // namespace dbwrapper_private