text: // Copyright (c) 2010 Satoshi Nakamoto
  // Copyright (c) 2009-2014 The Straks developers
  // Distributed under the MIT/X11 software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include "alert.h"
  
  #include "key.h"
  #include "net.h"
  #include "ui_interface.h"
  #include "util.h"
  
  #include <stdint.h>
  #include <algorithm>
  #include <map>
  
  #include <boost/algorithm/string/classification.hpp>
  #include <boost/algorithm/string/replace.hpp>
  #include <boost/foreach.hpp>
  
  
  using namespace std;
  
  map<uint256, CAlert> mapAlerts;
  CCriticalSection cs_mapAlerts;
  
  void CUnsignedAlert::SetNull()
  {
      nVersion = 1;
      nRelayUntil = 0;
      nExpiration = 0;
      nID = 0;
      nCancel = 0;
      setCancel.clear();
      nMinVer = 0;
      nMaxVer = 0;
      setSubVer.clear();
      nPriority = 0;
  
      strComment.clear();
      strStatusBar.clear();
      strReserved.clear();
  }
  
  std::string CUnsignedAlert::ToString() const
  {
      std::string strSetCancel;
      BOOST_FOREACH(int n, setCancel)
          strSetCancel += strprintf("%d ", n);
      std::string strSetSubVer;
      BOOST_FOREACH(std::string str, setSubVer)
          strSetSubVer += "\"" + str + "\" ";
      return strprintf(
          "CAlert(\n"
          "    nVersion     = %d\n"
          "    nRelayUntil  = %d\n"
          "    nExpiration  = %d\n"
          "    nID          = %d\n"
          "    nCancel      = %d\n"
          "    setCancel    = %s\n"
          "    nMinVer      = %d\n"
          "    nMaxVer      = %d\n"
          "    setSubVer    = %s\n"
          "    nPriority    = %d\n"
          "    strComment   = \"%s\"\n"
          "    strStatusBar = \"%s\"\n"
          ")\n",
          nVersion,
          nRelayUntil,
          nExpiration,
          nID,
          nCancel,
          strSetCancel,
          nMinVer,
          nMaxVer,
          strSetSubVer,
          nPriority,
          strComment,
          strStatusBar);
  }
  
  void CUnsignedAlert::print() const
  {
      LogPrintf("%s", ToString());
  }
  
  void CAlert::SetNull()
  {
      CUnsignedAlert::SetNull();
      vchMsg.clear();
      vchSig.clear();
  }
  
  bool CAlert::IsNull() const
  {
      return (nExpiration == 0);
  }
  
  uint256 CAlert::GetHash() const
  {
      return Hash(this->vchMsg.begin(), this->vchMsg.end());
  }
  
  bool CAlert::IsInEffect() const
  {
      return (GetAdjustedTime() < nExpiration);
  }
  
  bool CAlert::Cancels(const CAlert& alert) const
  {
      if (!IsInEffect())
          return false; // this was a no-op before 31403
      return (alert.nID <= nCancel || setCancel.count(alert.nID));
  }
  
  bool CAlert::AppliesTo(int nVersion, std::string strSubVerIn) const
  {
      // TODO: rework for client-version-embedded-in-strSubVer ?
      return (IsInEffect() &&
              nMinVer <= nVersion && nVersion <= nMaxVer &&
              (setSubVer.empty() || setSubVer.count(strSubVerIn)));
  }
  
  bool CAlert::AppliesToMe() const
  {
      return AppliesTo(PROTOCOL_VERSION, FormatSubVersion(CLIENT_NAME, CLIENT_VERSION, std::vector<std::string>()));
  }
  
  bool CAlert::RelayTo(CNode* pnode) const
  {
      if (!IsInEffect())
          return false;
      // returns true if wasn't already contained in the set
      if (pnode->setKnown.insert(GetHash()).second)
      {
          if (AppliesTo(pnode->nVersion, pnode->strSubVer) ||
              AppliesToMe() ||
              GetAdjustedTime() < nRelayUntil)
          {
              pnode->PushMessage("alert", *this);
              return true;
          }
      }
      return false;
  }
  
  bool CAlert::CheckSignature() const
  {
      CPubKey key(Params().AlertKey());
      if (!key.Verify(Hash(vchMsg.begin(), vchMsg.end()), vchSig))
          return error("CAlert::CheckSignature() : verify signature failed");
  
      // Now unserialize the data
      CDataStream sMsg(vchMsg, SER_NETWORK, PROTOCOL_VERSION);
      sMsg >> *(CUnsignedAlert*)this;
      return true;
  }
  
  CAlert CAlert::getAlertByHash(const uint256 &hash)
  {
      CAlert retval;
      {
          LOCK(cs_mapAlerts);
          map<uint256, CAlert>::iterator mi = mapAlerts.find(hash);
          if(mi != mapAlerts.end())
              retval = mi->second;
      }
      return retval;
  }
  
  bool CAlert::ProcessAlert(bool fThread)
  {
      if (!CheckSignature())
          return false;
      if (!IsInEffect())
          return false;
  
      // alert.nID=max is reserved for if the alert key is
      // compromised. It must have a pre-defined message,
      // must never expire, must apply to all versions,
      // and must cancel all previous
      // alerts or it will be ignored (so an attacker can't
      // send an "everything is OK, don't panic" version that
      // cannot be overridden):
      int maxInt = std::numeric_limits<int>::max();
      if (nID == maxInt)
      {
          if (!(
                  nExpiration == maxInt &&
                  nCancel == (maxInt-1) &&
                  nMinVer == 0 &&
                  nMaxVer == maxInt &&
                  setSubVer.empty() &&
                  nPriority == maxInt &&
                  strStatusBar == "URGENT: Alert key compromised, upgrade required"
                  ))
              return false;
      }
  
      {
          LOCK(cs_mapAlerts);
          // Cancel previous alerts
          for (map<uint256, CAlert>::iterator mi = mapAlerts.begin(); mi != mapAlerts.end();)
          {
              const CAlert& alert = (*mi).second;
              if (Cancels(alert))
              {
                  LogPrint("alert", "cancelling alert %d\n", alert.nID);
                  uiInterface.NotifyAlertChanged((*mi).first, CT_DELETED);
                  mapAlerts.erase(mi++);
              }
              else if (!alert.IsInEffect())
              {
                  LogPrint("alert", "expiring alert %d\n", alert.nID);
                  uiInterface.NotifyAlertChanged((*mi).first, CT_DELETED);
                  mapAlerts.erase(mi++);
              }
              else
                  mi++;
          }
  
          // Check if this alert has been cancelled
          BOOST_FOREACH(PAIRTYPE(const uint256, CAlert)& item, mapAlerts)
          {
              const CAlert& alert = item.second;
              if (alert.Cancels(*this))
              {
                  LogPrint("alert", "alert already cancelled by %d\n", alert.nID);
                  return false;
              }
          }
  
          // Add to mapAlerts
          mapAlerts.insert(make_pair(GetHash(), *this));
          // Notify UI and -alertnotify if it applies to me
          if(AppliesToMe())
          {
              uiInterface.NotifyAlertChanged(GetHash(), CT_NEW);
              Notify(strStatusBar, fThread);
          }
      }
  
      LogPrint("alert", "accepted alert %d, AppliesToMe()=%d\n", nID, AppliesToMe());
      return true;
  }
  
  void
  CAlert::Notify(const std::string& strMessage, bool fThread)
  {
      std::string strCmd = GetArg("-alertnotify", "");
      if (strCmd.empty()) return;
  
      // Alert text should be plain ascii coming from a trusted source, but to
      // be safe we first strip anything not in safeChars, then add single quotes around
      // the whole string before passing it to the shell:
      std::string singleQuote("'");
      std::string safeStatus = SanitizeString(strMessage);
      safeStatus = singleQuote+safeStatus+singleQuote;
      boost::replace_all(strCmd, "%s", safeStatus);
  
      if (fThread)
          boost::thread t(runCommand, strCmd); // thread runs free
      else
          runCommand(strCmd);
  }
  