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PowerDNS / pdns / 16499376415

24 Jul 2025 02:15PM UTC coverage: 65.862% (+0.01%) from 65.849%
16499376415

Pull #15918

github

web-flow
Merge e579d8f29 into 72d09ba0a
Pull Request #15918: dnsdist: Update a cache's atomic counter without holding the lock

42014 of 92370 branches covered (45.48%)

Branch coverage included in aggregate %.

9 of 11 new or added lines in 1 file covered. (81.82%)

26 existing lines in 8 files now uncovered.

127848 of 165535 relevant lines covered (77.23%)

5795697.29 hits per line

Source File
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61.16
/modules/pipebackend/pipebackend.cc
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/*
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 * This file is part of PowerDNS or dnsdist.
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 * Copyright -- PowerDNS.COM B.V. and its contributors
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of version 2 of the GNU General Public License as
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 * published by the Free Software Foundation.
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 *
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 * In addition, for the avoidance of any doubt, permission is granted to
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 * link this program with OpenSSL and to (re)distribute the binaries
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 * produced as the result of such linking.
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 *
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 *
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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 */
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <string>
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#include <map>
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#include <unistd.h>
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#include <stdlib.h>
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#include <sstream>
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#include "coprocess.hh"
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#include "pdns/namespaces.hh"
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#include "pdns/dns.hh"
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#include "pdns/dnsbackend.hh"
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#include "pdns/dnspacket.hh"
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#include "pdns/pdnsexception.hh"
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#include "pdns/logger.hh"
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#include "pdns/arguments.hh"
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include "pipebackend.hh"
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// The following requirement guarantees UnknownDomainID will get output as "-1"
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// for compatibility.
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static_assert(std::is_signed<domainid_t>::value);
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static const char* kBackendId = "[PIPEBackend]";
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CoWrapper::CoWrapper(const string& command, int timeout, int abiVersion)
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{
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  d_command = command;
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  d_timeout = timeout;
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  d_abiVersion = abiVersion;
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  launch(); // let exceptions fall through - if initial launch fails, we want to die
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  // I think
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}
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CoWrapper::~CoWrapper() = default;
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void CoWrapper::launch()
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{
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  if (d_cp)
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    return;
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  if (d_command.empty())
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    throw ArgException("pipe-command is not specified");
×
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  if (isUnixSocket(d_command)) {
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    d_cp = std::make_unique<UnixRemote>(d_command);
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  }
×
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  else {
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    auto coprocess = std::make_unique<CoProcess>(d_command, d_timeout);
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    coprocess->launch();
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    d_cp = std::move(coprocess);
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  }
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  d_cp->send("HELO\t" + std::to_string(d_abiVersion));
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  string banner;
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  d_cp->receive(banner);
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  g_log << Logger::Error << "Backend launched with banner: " << banner << endl;
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}
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void CoWrapper::send(const string& line)
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{
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  launch();
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  try {
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    d_cp->send(line);
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    return;
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  }
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  catch (PDNSException& ae) {
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    d_cp.reset();
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    throw;
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  }
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}
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void CoWrapper::receive(string& line)
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{
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  launch();
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  try {
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    d_cp->receive(line);
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    return;
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  }
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  catch (PDNSException& ae) {
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    g_log << Logger::Warning << kBackendId << " Unable to receive data from coprocess. " << ae.reason << endl;
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    d_cp.reset();
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    throw;
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  }
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}
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PipeBackend::PipeBackend(const string& suffix)
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{
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  d_disavow = false;
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  signal(SIGCHLD, SIG_IGN);
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  setArgPrefix("pipe" + suffix);
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  try {
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    launch();
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  }
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  catch (const ArgException& A) {
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    g_log << Logger::Error << kBackendId << " Unable to launch, fatal argument error: " << A.reason << endl;
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    throw;
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  }
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  catch (...) {
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    throw;
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  }
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}
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void PipeBackend::launch()
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{
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  if (d_coproc)
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    return;
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  try {
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    if (!getArg("regex").empty()) {
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      d_regex = std::make_unique<Regex>(getArg("regex"));
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    }
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    d_regexstr = getArg("regex");
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    d_abiVersion = getArgAsNum("abi-version");
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    d_coproc = std::make_unique<CoWrapper>(getArg("command"), getArgAsNum("timeout"), getArgAsNum("abi-version"));
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  }
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  catch (const ArgException& A) {
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    cleanup();
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    throw;
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  }
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}
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/*
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 * Cleans up the co-process wrapper
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 */
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void PipeBackend::cleanup()
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{
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  d_coproc.reset(nullptr);
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  d_regex.reset();
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  d_regexstr = string();
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  d_abiVersion = 0;
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}
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void PipeBackend::lookup(const QType& qtype, const DNSName& qname, domainid_t zoneId, DNSPacket* pkt_p)
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{
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  try {
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    launch();
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    d_disavow = false;
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    if (d_regex && !d_regex->match(qname.toStringRootDot())) {
17!
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      if (::arg().mustDo("query-logging"))
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        g_log << Logger::Error << "Query for '" << qname << "' failed regex '" << d_regexstr << "'" << endl;
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      d_disavow = true; // don't pass to backend
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    }
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    else {
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      ostringstream query;
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      string localIP = "0.0.0.0";
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      string remoteIP = "0.0.0.0";
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      Netmask realRemote("0.0.0.0/0");
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      if (pkt_p) {
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        localIP = pkt_p->getLocal().toString();
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        realRemote = pkt_p->getRealRemote();
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        remoteIP = pkt_p->getInnerRemote().toString();
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      }
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      // abi-version = 1
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      // type    qname           qclass  qtype   id      remote-ip-address
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      query << "Q\t" << qname.toStringRootDot() << "\tIN\t" << qtype.toString() << "\t" << zoneId << "\t" << remoteIP;
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      // add the local-ip-address if abi-version is set to 2
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      if (d_abiVersion >= 2)
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        query << "\t" << localIP;
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      if (d_abiVersion >= 3)
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        query << "\t" << realRemote.toString();
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      if (::arg().mustDo("query-logging"))
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        g_log << Logger::Error << "Query: '" << query.str() << "'" << endl;
×
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      d_coproc->send(query.str());
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    }
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  }
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  catch (PDNSException& pe) {
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    g_log << Logger::Error << kBackendId << " Error from coprocess: " << pe.reason << endl;
×
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    d_disavow = true;
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  }
×
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  d_qtype = qtype;
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  d_qname = qname;
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}
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bool PipeBackend::list(const ZoneName& target, domainid_t domain_id, bool /* include_disabled */)
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{
×
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  try {
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    launch();
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    d_disavow = false;
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    ostringstream query;
×
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    // The question format:
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    // type    qname           qclass  qtype   id      ip-address
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    if (d_abiVersion >= 4)
×
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      query << "AXFR\t" << domain_id << "\t" << target.toStringRootDot();
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    else
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      query << "AXFR\t" << domain_id;
×
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    d_coproc->send(query.str());
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  }
×
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  catch (PDNSException& ae) {
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    g_log << Logger::Error << kBackendId << " Error from coprocess: " << ae.reason << endl;
×
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  }
×
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  d_qname = DNSName(std::to_string(domain_id)); // why do we store a number here??
×
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  return true;
×
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}
×
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string PipeBackend::directBackendCmd(const string& query)
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{
×
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  if (d_abiVersion < 5)
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    return "not supported on ABI version " + std::to_string(d_abiVersion) + " (use ABI version 5 or later)\n";
×
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230
  try {
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    launch();
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    ostringstream oss;
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    oss << "CMD\t" << query;
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    d_coproc->send(oss.str());
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  }
×
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  catch (PDNSException& ae) {
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    g_log << Logger::Error << kBackendId << " Error from coprocess: " << ae.reason << endl;
×
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    cleanup();
×
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  }
×
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  ostringstream oss;
×
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  while (true) {
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    string line;
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    d_coproc->receive(line);
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    if (line == "END")
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      break;
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    oss << line << std::endl;
×
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  };
×
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250
  return oss.str();
×
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}
×
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//! For the dynamic loader
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DNSBackend* PipeBackend::maker()
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{
×
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  try {
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    return new PipeBackend();
×
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  }
×
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  catch (...) {
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    g_log << Logger::Error << kBackendId << " Unable to instantiate a pipebackend!" << endl;
×
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    return nullptr;
×
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  }
×
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}
×
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265
PipeBackend::~PipeBackend()
266
{
2✔
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  cleanup();
2✔
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}
2✔
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270
bool PipeBackend::get(DNSResourceRecord& r)
271
{
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272
  if (d_disavow) // this query has been blocked
27!
273
    return false;
×
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275
  string line;
27✔
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277
  // The answer format:
278
  // DATA    qname           qclass  qtype   ttl     id      content
279
  unsigned int extraFields = 0;
27✔
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  if (d_abiVersion >= 3)
27✔
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    extraFields = 2;
21✔
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283
  try {
27✔
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    launch();
27✔
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    for (;;) {
27✔
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      d_coproc->receive(line);
27✔
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      vector<string> parts;
27✔
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      stringtok(parts, line, "\t");
27✔
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      if (parts.empty()) {
27!
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        g_log << Logger::Error << kBackendId << " Coprocess returned empty line in query for " << d_qname << endl;
×
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        throw PDNSException("Format error communicating with coprocess");
×
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      }
×
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      else if (parts[0] == "FAIL") {
27!
294
        throw DBException("coprocess returned a FAIL");
×
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      }
×
296
      else if (parts[0] == "END") {
27✔
297
        return false;
17✔
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      }
17✔
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      else if (parts[0] == "LOG") {
10!
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        g_log << Logger::Error << "Coprocess: " << line.substr(4) << endl;
×
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        continue;
×
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      }
×
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      else if (parts[0] == "DATA") { // yay
10!
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        if (parts.size() < 7 + extraFields) {
10!
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          g_log << Logger::Error << kBackendId << " Coprocess returned incomplete or empty line in data section for query for " << d_qname << endl;
×
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          throw PDNSException("Format error communicating with coprocess in data section");
×
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          // now what?
308
        }
×
309

310
        if (d_abiVersion >= 3) {
10✔
311
          r.scopeMask = std::stoi(parts[1]);
8✔
312
          r.auth = (parts[2] == "1");
8✔
313
        }
8✔
314
        else {
2✔
315
          r.scopeMask = 0;
2✔
316
          r.auth = true;
2✔
317
        }
2✔
318
        r.qname = DNSName(parts[1 + extraFields]);
10✔
319
        r.qtype = parts[3 + extraFields];
10✔
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        pdns::checked_stoi_into(r.ttl, parts[4 + extraFields]);
10✔
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        pdns::checked_stoi_into(r.domain_id, parts[5 + extraFields]);
10✔
322

323
        if (r.qtype.getCode() != QType::MX && r.qtype.getCode() != QType::SRV) {
10!
324
          r.content.clear();
9✔
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          for (unsigned int n = 6 + extraFields; n < parts.size(); ++n) {
18✔
326
            if (n != 6 + extraFields)
9!
327
              r.content.append(1, ' ');
×
328
            r.content.append(parts[n]);
9✔
329
          }
9✔
330
        }
9✔
331
        else {
1✔
332
          if (parts.size() < 8 + extraFields) {
1!
333
            g_log << Logger::Error << kBackendId << " Coprocess returned incomplete MX/SRV line in data section for query for " << d_qname << endl;
×
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            throw PDNSException("Format error communicating with coprocess in data section of MX/SRV record");
×
335
          }
×
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337
          r.content = parts[6 + extraFields] + " " + parts[7 + extraFields];
1✔
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        }
1✔
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        break;
10✔
340
      }
10✔
UNCOV
341
      else
×
UNCOV
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        throw PDNSException("Coprocess backend sent incorrect response '" + line + "'");
×
343
    }
27✔
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  }
27✔
345
  catch (DBException& dbe) {
27✔
346
    g_log << Logger::Error << kBackendId << " " << dbe.reason << endl;
×
347
    throw;
×
348
  }
×
349
  catch (PDNSException& pe) {
27✔
350
    g_log << Logger::Error << kBackendId << " " << pe.reason << endl;
×
351
    cleanup();
×
352
    throw;
×
353
  }
×
354
  return true;
10✔
355
}
27✔
356

357
//
358
// Magic class that is activated when the dynamic library is loaded
359
//
360

361
class PipeFactory : public BackendFactory
362
{
363
public:
364
  PipeFactory() :
365
    BackendFactory("pipe") {}
5,854✔
366

367
  void declareArguments(const string& suffix = "") override
368
  {
2✔
369
    declare(suffix, "command", "Command to execute for piping questions to", "");
2✔
370
    declare(suffix, "timeout", "Number of milliseconds to wait for an answer", "2000");
2✔
371
    declare(suffix, "regex", "Regular expression of queries to pass to coprocess", "");
2✔
372
    declare(suffix, "abi-version", "Version of the pipe backend ABI", "1");
2✔
373
  }
2✔
374

375
  DNSBackend* make(const string& suffix = "") override
376
  {
10✔
377
    return new PipeBackend(suffix);
10✔
378
  }
10✔
379
};
380

381
class PipeLoader
382
{
383
public:
384
  PipeLoader()
385
  {
5,854✔
386
    BackendMakers().report(std::make_unique<PipeFactory>());
5,854✔
387
    g_log << Logger::Info << kBackendId << " This is the pipe backend version " VERSION
5,854✔
388
#ifndef REPRODUCIBLE
5,854✔
389
          << " (" __DATE__ " " __TIME__ ")"
5,854✔
390
#endif
5,854✔
391
          << " reporting" << endl;
5,854✔
392
  }
5,854✔
393
};
394

395
static PipeLoader pipeloader;
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