dns_config_service_linux.cc | Explore in Territory

// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40284755): Remove this and spanify to fix the errors.
#pragma allow_unsafe_buffers
#endif

#include "net/dns/dns_config_service_linux.h"

#include <netdb.h>
#include <netinet/in.h>
#include <resolv.h>
#include <sys/socket.h>
#include <sys/types.h>

#include <map>
#include <memory>
#include <optional>
#include <string>
#include <type_traits>
#include <utility>
#include <vector>

#include "base/check.h"
#include "base/files/file_path.h"
#include "base/files/file_path_watcher.h"
#include "base/functional/bind.h"
#include "base/functional/callback.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/memory/raw_ptr.h"
#include "base/metrics/histogram_functions.h"
#include "base/metrics/histogram_macros.h"
#include "base/sequence_checker.h"
#include "base/threading/scoped_blocking_call.h"
#include "base/time/time.h"
#include "net/base/ip_endpoint.h"
#include "net/dns/dns_config.h"
#include "net/dns/nsswitch_reader.h"
#include "net/dns/public/resolv_reader.h"
#include "net/dns/serial_worker.h"

namespace net {

namespace internal {

namespace {

const base::FilePath::CharType kFilePathHosts[] = …);

#ifndef _PATH_RESCONF  // Normally defined in <resolv.h>
#define _PATH_RESCONF …
#endif

constexpr base::FilePath::CharType kFilePathResolv[] = …;

#ifndef _PATH_NSSWITCH_CONF  // Normally defined in <netdb.h>
#define _PATH_NSSWITCH_CONF …
#endif

constexpr base::FilePath::CharType kFilePathNsswitch[] = …;

std::optional<DnsConfig> ConvertResStateToDnsConfig(
    const struct __res_state& res) { … }

// Helper to add the effective result of `action` to `in_out_parsed_behavior`.
// Returns false if `action` results in inconsistent behavior (setting an action
// for a status that already has a different action).
bool SetActionBehavior(const NsswitchReader::ServiceAction& action,
                       std::map<NsswitchReader::Status, NsswitchReader::Action>&
                           in_out_parsed_behavior) { … }

// Helper to determine if `actions` match `expected_actions`, meaning `actions`
// contains no unknown statuses or actions and for every expectation set in
// `expected_actions`, the expected action matches the effective result from
// `actions`.
bool AreActionsCompatible(
    const std::vector<NsswitchReader::ServiceAction>& actions,
    const std::map<NsswitchReader::Status, NsswitchReader::Action>
        expected_actions) { … }

// These values are emitted in metrics. Entries should not be renumbered and
// numeric values should never be reused. (See NsswitchIncompatibleReason in
// tools/metrics/histograms/enums.xml.)
enum class IncompatibleNsswitchReason { … };

void RecordIncompatibleNsswitchReason(
    IncompatibleNsswitchReason reason,
    std::optional<NsswitchReader::Service> service_token) { … }

bool IsNsswitchConfigCompatible(
    const std::vector<NsswitchReader::ServiceSpecification>& nsswitch_hosts) { … }

}  // namespace

class DnsConfigServiceLinux::Watcher : public DnsConfigService::Watcher { … };

// A SerialWorker that uses libresolv to initialize res_state and converts
// it to DnsConfig.
class DnsConfigServiceLinux::ConfigReader : public SerialWorker { … };

DnsConfigServiceLinux::DnsConfigServiceLinux()
    : … { … }

DnsConfigServiceLinux::~DnsConfigServiceLinux() { … }

void DnsConfigServiceLinux::ReadConfigNow() { … }

bool DnsConfigServiceLinux::StartWatching() { … }

void DnsConfigServiceLinux::CreateReader() { … }

}  // namespace internal

// static
std::unique_ptr<DnsConfigService> DnsConfigService::CreateSystemService() { … }

}  // namespace net
chromium/net/dns/dns_config_service_linux.cc
