From 928d3a011cc66c7f907c4d053f674ea77dc611cc Mon Sep 17 00:00:00 2001
From: Jeff Garzik <jgarzik@exmulti.com>
Date: Wed, 16 May 2012 22:11:19 -0400
Subject: CAddrDB: Replace BDB-managed addr.dat with internally managed
 peers.dat

---
 src/db.cpp | 129 +++++++++++++++++++++++++++++++++++++------------------------
 1 file changed, 79 insertions(+), 50 deletions(-)

(limited to 'src/db.cpp')

diff --git a/src/db.cpp b/src/db.cpp
index 5bd0528202..5b36a8f1f5 100644
--- a/src/db.cpp
+++ b/src/db.cpp
@@ -164,8 +164,6 @@ void CDB::Close()
     unsigned int nMinutes = 0;
     if (fReadOnly)
         nMinutes = 1;
-    if (strFile == "addr.dat")
-        nMinutes = 2;
     if (strFile == "blkindex.dat")
         nMinutes = 2;
     if (strFile == "blkindex.dat" && IsInitialBlockDownload())
@@ -310,7 +308,7 @@ void DBFlush(bool fShutdown)
                 CloseDb(strFile);
                 printf("%s checkpoint\n", strFile.c_str());
                 dbenv.txn_checkpoint(0, 0, 0);
-                if ((strFile != "blkindex.dat" && strFile != "addr.dat") || fDetachDB) {
+                if (strFile != "blkindex.dat" || fDetachDB) {
                     printf("%s detach\n", strFile.c_str());
                     dbenv.lsn_reset(strFile.c_str(), 0);
                 }
@@ -737,65 +735,96 @@ bool CTxDB::LoadBlockIndex()
 // CAddrDB
 //
 
-bool CAddrDB::WriteAddrman(const CAddrMan& addrman)
+
+CAddrDB::CAddrDB()
 {
-    return Write(string("addrman"), addrman);
+    pathAddr = GetDataDir() / "peers.dat";
 }
 
-bool CAddrDB::LoadAddresses()
+bool CAddrDB::Write(const CAddrMan& addr)
 {
-    if (Read(string("addrman"), addrman))
-    {
-        printf("Loaded %i addresses\n", addrman.size());
-        return true;
+    // Generate random temporary filename
+    unsigned short randv = 0;
+    RAND_bytes((unsigned char *)&randv, sizeof(randv));
+    std::string tmpfn = strprintf("peers.dat.%04x", randv);
+
+    // serialize addresses, checksum data up to that point, then append csum
+    CDataStream ssPeers(SER_DISK, CLIENT_VERSION);
+    ssPeers << FLATDATA(pchMessageStart);
+    ssPeers << addr;
+    uint256 hash = Hash(ssPeers.begin(), ssPeers.end());
+    ssPeers << hash;
+
+    // open temp output file, and associate with CAutoFile
+    boost::filesystem::path pathTmp = GetDataDir() / tmpfn;
+    FILE *file = fopen(pathTmp.string().c_str(), "wb");
+    CAutoFile fileout = CAutoFile(file, SER_DISK, CLIENT_VERSION);
+    if (!fileout)
+        return error("CAddrman::Write() : open failed");
+
+    // Write and commit header, data
+    try {
+        fileout << ssPeers;
     }
-    
-    // Read pre-0.6 addr records
+    catch (std::exception &e) {
+        return error("CAddrman::Write() : I/O error");
+    }
+    FileCommit(fileout);
+    fileout.fclose();
 
-    vector<CAddress> vAddr;
-    vector<vector<unsigned char> > vDelete;
+    // replace existing peers.dat, if any, with new peers.dat.XXXX
+    if (!RenameOver(pathTmp, pathAddr))
+        return error("CAddrman::Write() : Rename-into-place failed");
 
-    // Get cursor
-    Dbc* pcursor = GetCursor();
-    if (!pcursor)
-        return false;
-
-    loop
-    {
-        // Read next record
-        CDataStream ssKey(SER_DISK, CLIENT_VERSION);
-        CDataStream ssValue(SER_DISK, CLIENT_VERSION);
-        int ret = ReadAtCursor(pcursor, ssKey, ssValue);
-        if (ret == DB_NOTFOUND)
-            break;
-        else if (ret != 0)
-            return false;
+    return true;
+}
 
-        // Unserialize
-        string strType;
-        ssKey >> strType;
-        if (strType == "addr")
-        {
-            CAddress addr;
-            ssValue >> addr;
-            vAddr.push_back(addr);
-        }
+bool CAddrDB::Read(CAddrMan& addr)
+{
+    // open input file, and associate with CAutoFile
+    FILE *file = fopen(pathAddr.string().c_str(), "rb");
+    CAutoFile filein = CAutoFile(file, SER_DISK, CLIENT_VERSION);
+    if (!filein)
+        return error("CAddrman::Read() : open failed");
+
+    // use file size to size memory buffer
+    int fileSize = GetFilesize(filein);
+    int dataSize = fileSize - sizeof(uint256);
+    vector<unsigned char> vchData;
+    vchData.resize(dataSize);
+    uint256 hashIn;
+
+    // read data and checksum from file
+    try {
+        filein.read((char *)&vchData[0], dataSize);
+        filein >> hashIn;
     }
-    pcursor->close();
+    catch (std::exception &e) {
+        return error("CAddrman::Read() 2 : I/O error or stream data corrupted");
+    }
+    filein.fclose();
 
-    addrman.Add(vAddr, CNetAddr("0.0.0.0"));
-    printf("Loaded %i addresses\n", addrman.size());
+    CDataStream ssPeers(vchData, SER_DISK, CLIENT_VERSION);
 
-    // Note: old records left; we ran into hangs-on-startup
-    // bugs for some users who (we think) were running after
-    // an unclean shutdown.
+    // verify stored checksum matches input data
+    uint256 hashTmp = Hash(ssPeers.begin(), ssPeers.end());
+    if (hashIn != hashTmp)
+        return error("CAddrman::Read() : checksum mismatch; data corrupted");
 
-    return true;
-}
+    // de-serialize address data
+    unsigned char pchMsgTmp[4];
+    try {
+        ssPeers >> FLATDATA(pchMsgTmp);
+        ssPeers >> addr;
+    }
+    catch (std::exception &e) {
+        return error("CAddrman::Read() : I/O error or stream data corrupted");
+    }
 
-bool LoadAddresses()
-{
-    return CAddrDB("cr+").LoadAddresses();
-}
+    // finally, verify the network matches ours
+    if (memcmp(pchMsgTmp, pchMessageStart, sizeof(pchMsgTmp)))
+        return error("CAddrman::Read() : invalid network magic number");
 
+    return true;
+}
 
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