unplugged-system/device/google/cuttlefish/host/libs/config/cuttlefish_config.cpp

/*
 * Copyright (C) 2018 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "host/libs/config/cuttlefish_config.h"

#include <algorithm>
#include <climits>
#include <cstdint>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iomanip>
#include <iterator>
#include <sstream>
#include <string>
#include <time.h>

#include <android-base/strings.h>
#include <android-base/logging.h>
#include <json/json.h>

#include "common/libs/utils/environment.h"
#include "common/libs/utils/files.h"
#include "host/libs/vm_manager/crosvm_manager.h"
#include "host/libs/vm_manager/gem5_manager.h"
#include "host/libs/vm_manager/qemu_manager.h"

namespace cuttlefish {
namespace {

static constexpr int kDefaultInstance = 1;

int InstanceFromString(std::string instance_str) {
  if (android::base::StartsWith(instance_str, kVsocUserPrefix)) {
    instance_str = instance_str.substr(std::string(kVsocUserPrefix).size());
  } else if (android::base::StartsWith(instance_str, kCvdNamePrefix)) {
    instance_str = instance_str.substr(std::string(kCvdNamePrefix).size());
  }

  int instance = std::stoi(instance_str);
  if (instance <= 0) {
    LOG(INFO) << "Failed to interpret \"" << instance_str << "\" as an id, "
              << "using instance id " << kDefaultInstance;
    return kDefaultInstance;
  }
  return instance;
}

int InstanceFromEnvironment() {
  std::string instance_str = StringFromEnv(kCuttlefishInstanceEnvVarName, "");
  if (instance_str.empty()) {
    // Try to get it from the user instead
    instance_str = StringFromEnv("USER", "");

    if (instance_str.empty()) {
      LOG(DEBUG) << kCuttlefishInstanceEnvVarName
                 << " and USER unset, using instance id " << kDefaultInstance;
      return kDefaultInstance;
    }
    if (!android::base::StartsWith(instance_str, kVsocUserPrefix)) {
      // No user or we don't recognize this user
      LOG(DEBUG) << "Non-vsoc user, using instance id " << kDefaultInstance;
      return kDefaultInstance;
    }
  }
  return InstanceFromString(instance_str);
}

const char* kInstances = "instances";


}  // namespace

const char* const kGpuModeAuto = "auto";
const char* const kGpuModeDrmVirgl = "drm_virgl";
const char* const kGpuModeGfxstream = "gfxstream";
const char* const kGpuModeGfxstreamGuestAngle = "gfxstream_guest_angle";
const char* const kGpuModeGuestSwiftshader = "guest_swiftshader";
const char* const kGpuModeNone = "none";

const char* const kHwComposerAuto = "auto";
const char* const kHwComposerDrm = "drm";
const char* const kHwComposerRanchu = "ranchu";
const char* const kHwComposerNone = "none";

std::string DefaultEnvironmentPath(const char* environment_key,
                                   const char* default_value,
                                   const char* subpath) {
  return StringFromEnv(environment_key, default_value) + "/" + subpath;
}

ConfigFragment::~ConfigFragment() = default;

static constexpr char kFragments[] = "fragments";
bool CuttlefishConfig::LoadFragment(ConfigFragment& fragment) const {
  if (!dictionary_->isMember(kFragments)) {
    LOG(ERROR) << "Fragments member was missing";
    return false;
  }
  const Json::Value& json_fragments = (*dictionary_)[kFragments];
  if (!json_fragments.isMember(fragment.Name())) {
    LOG(ERROR) << "Could not find a fragment called " << fragment.Name();
    return false;
  }
  return fragment.Deserialize(json_fragments[fragment.Name()]);
}
bool CuttlefishConfig::SaveFragment(const ConfigFragment& fragment) {
  Json::Value& json_fragments = (*dictionary_)[kFragments];
  if (json_fragments.isMember(fragment.Name())) {
    LOG(ERROR) << "Already have a fragment called " << fragment.Name();
    return false;
  }
  json_fragments[fragment.Name()] = fragment.Serialize();
  return true;
}

static constexpr char kRootDir[] = "root_dir";
std::string CuttlefishConfig::root_dir() const {
  return (*dictionary_)[kRootDir].asString();
}
void CuttlefishConfig::set_root_dir(const std::string& root_dir) {
  (*dictionary_)[kRootDir] = root_dir;
}

static constexpr char kVmManager[] = "vm_manager";
std::string CuttlefishConfig::vm_manager() const {
  return (*dictionary_)[kVmManager].asString();
}
void CuttlefishConfig::set_vm_manager(const std::string& name) {
  (*dictionary_)[kVmManager] = name;
}

static SecureHal StringToSecureHal(std::string mode) {
  std::transform(mode.begin(), mode.end(), mode.begin(), ::tolower);
  if (mode == "keymint") {
    return SecureHal::Keymint;
  } else if (mode == "gatekeeper") {
    return SecureHal::Gatekeeper;
  } else {
    return SecureHal::Unknown;
  }
}

static constexpr char kSecureHals[] = "secure_hals";
std::set<SecureHal> CuttlefishConfig::secure_hals() const {
  std::set<SecureHal> args_set;
  for (auto& hal : (*dictionary_)[kSecureHals]) {
    args_set.insert(StringToSecureHal(hal.asString()));
  }
  return args_set;
}
void CuttlefishConfig::set_secure_hals(const std::set<std::string>& hals) {
  Json::Value hals_json_obj(Json::arrayValue);
  for (const auto& hal : hals) {
    hals_json_obj.append(hal);
  }
  (*dictionary_)[kSecureHals] = hals_json_obj;
}

static constexpr char kCrosvmBinary[] = "crosvm_binary";
std::string CuttlefishConfig::crosvm_binary() const {
  return (*dictionary_)[kCrosvmBinary].asString();
}
void CuttlefishConfig::set_crosvm_binary(const std::string& crosvm_binary) {
  (*dictionary_)[kCrosvmBinary] = crosvm_binary;
}

static constexpr char kGem5DebugFlags[] = "gem5_debug_flags";
std::string CuttlefishConfig::gem5_debug_flags() const {
  return (*dictionary_)[kGem5DebugFlags].asString();
}
void CuttlefishConfig::set_gem5_debug_flags(const std::string& gem5_debug_flags) {
  (*dictionary_)[kGem5DebugFlags] = gem5_debug_flags;
}

static constexpr char kWebRTCCertsDir[] = "webrtc_certs_dir";
void CuttlefishConfig::set_webrtc_certs_dir(const std::string& certs_dir) {
  (*dictionary_)[kWebRTCCertsDir] = certs_dir;
}
std::string CuttlefishConfig::webrtc_certs_dir() const {
  return (*dictionary_)[kWebRTCCertsDir].asString();
}

static constexpr char kSigServerPort[] = "webrtc_sig_server_port";
void CuttlefishConfig::set_sig_server_port(int port) {
  (*dictionary_)[kSigServerPort] = port;
}
int CuttlefishConfig::sig_server_port() const {
  return (*dictionary_)[kSigServerPort].asInt();
}

static constexpr char kSigServerAddress[] = "webrtc_sig_server_addr";
void CuttlefishConfig::set_sig_server_address(const std::string& addr) {
  (*dictionary_)[kSigServerAddress] = addr;
}
std::string CuttlefishConfig::sig_server_address() const {
  return (*dictionary_)[kSigServerAddress].asString();
}

static constexpr char kSigServerPath[] = "webrtc_sig_server_path";
void CuttlefishConfig::set_sig_server_path(const std::string& path) {
  // Don't use SetPath here, it's a URL path not a file system path
  (*dictionary_)[kSigServerPath] = path;
}
std::string CuttlefishConfig::sig_server_path() const {
  return (*dictionary_)[kSigServerPath].asString();
}

static constexpr char kSigServerSecure[] = "webrtc_sig_server_secure";
void CuttlefishConfig::set_sig_server_secure(bool secure) {
  (*dictionary_)[kSigServerSecure] = secure;
}
bool CuttlefishConfig::sig_server_secure() const {
  return (*dictionary_)[kSigServerSecure].asBool();
}

static constexpr char kSigServerStrict[] = "webrtc_sig_server_strict";
void CuttlefishConfig::set_sig_server_strict(bool strict) {
  (*dictionary_)[kSigServerStrict] = strict;
}
bool CuttlefishConfig::sig_server_strict() const {
  return (*dictionary_)[kSigServerStrict].asBool();
}

static constexpr char kHostToolsVersion[] = "host_tools_version";
void CuttlefishConfig::set_host_tools_version(
    const std::map<std::string, uint32_t>& versions) {
  Json::Value json(Json::objectValue);
  for (const auto& [key, value] : versions) {
    json[key] = value;
  }
  (*dictionary_)[kHostToolsVersion] = json;
}
std::map<std::string, uint32_t> CuttlefishConfig::host_tools_version() const {
  if (!dictionary_->isMember(kHostToolsVersion)) {
    return {};
  }
  std::map<std::string, uint32_t> versions;
  const auto& elem = (*dictionary_)[kHostToolsVersion];
  for (auto it = elem.begin(); it != elem.end(); it++) {
    versions[it.key().asString()] = it->asUInt();
  }
  return versions;
}

static constexpr char kenableHostUwb[] = "enable_host_uwb";
void CuttlefishConfig::set_enable_host_uwb(bool enable_host_uwb) {
  (*dictionary_)[kenableHostUwb] = enable_host_uwb;
}
bool CuttlefishConfig::enable_host_uwb() const {
  return (*dictionary_)[kenableHostUwb].asBool();
}

static constexpr char kenableHostUwbConnector[] = "enable_host_uwb_connector";
void CuttlefishConfig::set_enable_host_uwb_connector(bool enable_host_uwb) {
  (*dictionary_)[kenableHostUwbConnector] = enable_host_uwb;
}
bool CuttlefishConfig::enable_host_uwb_connector() const {
  return (*dictionary_)[kenableHostUwbConnector].asBool();
}

static constexpr char kPicaUciPort[] = "pica_uci_port";
int CuttlefishConfig::pica_uci_port() const {
  return (*dictionary_)[kPicaUciPort].asInt();
}
void CuttlefishConfig::set_pica_uci_port(int pica_uci_port) {
  (*dictionary_)[kPicaUciPort] = pica_uci_port;
}

static constexpr char kenableHostBluetooth[] = "enable_host_bluetooth";
void CuttlefishConfig::set_enable_host_bluetooth(bool enable_host_bluetooth) {
  (*dictionary_)[kenableHostBluetooth] = enable_host_bluetooth;
}
bool CuttlefishConfig::enable_host_bluetooth() const {
  return (*dictionary_)[kenableHostBluetooth].asBool();
}

static constexpr char kenableHostBluetoothConnector[] = "enable_host_bluetooth_connector";
void CuttlefishConfig::set_enable_host_bluetooth_connector(bool enable_host_bluetooth) {
  (*dictionary_)[kenableHostBluetoothConnector] = enable_host_bluetooth;
}
bool CuttlefishConfig::enable_host_bluetooth_connector() const {
  return (*dictionary_)[kenableHostBluetoothConnector].asBool();
}

static constexpr char kNetsimRadios[] = "netsim_radios";

void CuttlefishConfig::netsim_radio_enable(NetsimRadio flag) {
  if (dictionary_->isMember(kNetsimRadios)) {
    // OR the radio to current set of radios
    (*dictionary_)[kNetsimRadios] = (*dictionary_)[kNetsimRadios].asInt() | flag;
  } else {
    (*dictionary_)[kNetsimRadios] = flag;
  }
}

bool CuttlefishConfig::netsim_radio_enabled(NetsimRadio flag) const {
  return (*dictionary_)[kNetsimRadios].asInt() & flag;
}

static constexpr char kEnableMetrics[] = "enable_metrics";
void CuttlefishConfig::set_enable_metrics(std::string enable_metrics) {
  (*dictionary_)[kEnableMetrics] = kUnknown;
  if (!enable_metrics.empty()) {
    switch (enable_metrics.at(0)) {
      case 'y':
      case 'Y':
        (*dictionary_)[kEnableMetrics] = kYes;
        break;
      case 'n':
      case 'N':
        (*dictionary_)[kEnableMetrics] = kNo;
        break;
    }
  }
}
CuttlefishConfig::Answer CuttlefishConfig::enable_metrics() const {
  return (CuttlefishConfig::Answer)(*dictionary_)[kEnableMetrics].asInt();
}

static constexpr char kMetricsBinary[] = "metrics_binary";
void CuttlefishConfig::set_metrics_binary(const std::string& metrics_binary) {
  (*dictionary_)[kMetricsBinary] = metrics_binary;
}
std::string CuttlefishConfig::metrics_binary() const {
  return (*dictionary_)[kMetricsBinary].asString();
}

static constexpr char kExtraKernelCmdline[] = "extra_kernel_cmdline";
void CuttlefishConfig::set_extra_kernel_cmdline(
    const std::string& extra_cmdline) {
  Json::Value args_json_obj(Json::arrayValue);
  for (const auto& arg : android::base::Split(extra_cmdline, " ")) {
    args_json_obj.append(arg);
  }
  (*dictionary_)[kExtraKernelCmdline] = args_json_obj;
}
std::vector<std::string> CuttlefishConfig::extra_kernel_cmdline() const {
  std::vector<std::string> cmdline;
  for (const Json::Value& arg : (*dictionary_)[kExtraKernelCmdline]) {
    cmdline.push_back(arg.asString());
  }
  return cmdline;
}

static constexpr char kExtraBootconfigArgs[] = "extra_bootconfig_args";
void CuttlefishConfig::set_extra_bootconfig_args(
    const std::string& extra_bootconfig_args) {
  Json::Value args_json_obj(Json::arrayValue);
  for (const auto& arg : android::base::Split(extra_bootconfig_args, " ")) {
    args_json_obj.append(arg);
  }
  (*dictionary_)[kExtraBootconfigArgs] = args_json_obj;
}
std::vector<std::string> CuttlefishConfig::extra_bootconfig_args() const {
  std::vector<std::string> bootconfig;
  for (const Json::Value& arg : (*dictionary_)[kExtraBootconfigArgs]) {
    bootconfig.push_back(arg.asString());
  }
  return bootconfig;
}

static constexpr char kVirtioMac80211Hwsim[] = "virtio_mac80211_hwsim";
void CuttlefishConfig::set_virtio_mac80211_hwsim(bool virtio_mac80211_hwsim) {
  (*dictionary_)[kVirtioMac80211Hwsim] = virtio_mac80211_hwsim;
}
bool CuttlefishConfig::virtio_mac80211_hwsim() const {
  return (*dictionary_)[kVirtioMac80211Hwsim].asBool();
}

static constexpr char kVhostUserMac80211Hwsim[] = "vhost_user_mac80211_hwsim";
void CuttlefishConfig::set_vhost_user_mac80211_hwsim(const std::string& path) {
  (*dictionary_)[kVhostUserMac80211Hwsim] = path;
}
std::string CuttlefishConfig::vhost_user_mac80211_hwsim() const {
  return (*dictionary_)[kVhostUserMac80211Hwsim].asString();
}

static constexpr char kWmediumdApiServerSocket[] = "wmediumd_api_server_socket";
void CuttlefishConfig::set_wmediumd_api_server_socket(const std::string& path) {
  (*dictionary_)[kWmediumdApiServerSocket] = path;
}
std::string CuttlefishConfig::wmediumd_api_server_socket() const {
  return (*dictionary_)[kWmediumdApiServerSocket].asString();
}

static constexpr char kApRootfsImage[] = "ap_rootfs_image";
std::string CuttlefishConfig::ap_rootfs_image() const {
  return (*dictionary_)[kApRootfsImage].asString();
}
void CuttlefishConfig::set_ap_rootfs_image(const std::string& ap_rootfs_image) {
  (*dictionary_)[kApRootfsImage] = ap_rootfs_image;
}

static constexpr char kApKernelImage[] = "ap_kernel_image";
std::string CuttlefishConfig::ap_kernel_image() const {
  return (*dictionary_)[kApKernelImage].asString();
}
void CuttlefishConfig::set_ap_kernel_image(const std::string& ap_kernel_image) {
  (*dictionary_)[kApKernelImage] = ap_kernel_image;
}

static constexpr char kWmediumdConfig[] = "wmediumd_config";
void CuttlefishConfig::set_wmediumd_config(const std::string& config) {
  (*dictionary_)[kWmediumdConfig] = config;
}
std::string CuttlefishConfig::wmediumd_config() const {
  return (*dictionary_)[kWmediumdConfig].asString();
}

static constexpr char kRootcanalArgs[] = "rootcanal_args";
void CuttlefishConfig::set_rootcanal_args(const std::string& rootcanal_args) {
  Json::Value args_json_obj(Json::arrayValue);
  for (const auto& arg : android::base::Split(rootcanal_args, " ")) {
    args_json_obj.append(arg);
  }
  (*dictionary_)[kRootcanalArgs] = args_json_obj;
}
std::vector<std::string> CuttlefishConfig::rootcanal_args() const {
  std::vector<std::string> rootcanal_args;
  for (const Json::Value& arg : (*dictionary_)[kRootcanalArgs]) {
    rootcanal_args.push_back(arg.asString());
  }
  return rootcanal_args;
}

static constexpr char kRootcanalHciPort[] = "rootcanal_hci_port";
int CuttlefishConfig::rootcanal_hci_port() const {
  return (*dictionary_)[kRootcanalHciPort].asInt();
}
void CuttlefishConfig::set_rootcanal_hci_port(int rootcanal_hci_port) {
  (*dictionary_)[kRootcanalHciPort] = rootcanal_hci_port;
}

static constexpr char kRootcanalLinkPort[] = "rootcanal_link_port";
int CuttlefishConfig::rootcanal_link_port() const {
  return (*dictionary_)[kRootcanalLinkPort].asInt();
}
void CuttlefishConfig::set_rootcanal_link_port(int rootcanal_link_port) {
  (*dictionary_)[kRootcanalLinkPort] = rootcanal_link_port;
}

static constexpr char kRootcanalLinkBlePort[] = "rootcanal_link_ble_port";
int CuttlefishConfig::rootcanal_link_ble_port() const {
  return (*dictionary_)[kRootcanalLinkBlePort].asInt();
}
void CuttlefishConfig::set_rootcanal_link_ble_port(
    int rootcanal_link_ble_port) {
  (*dictionary_)[kRootcanalLinkBlePort] = rootcanal_link_ble_port;
}

static constexpr char kRootcanalTestPort[] = "rootcanal_test_port";
int CuttlefishConfig::rootcanal_test_port() const {
  return (*dictionary_)[kRootcanalTestPort].asInt();
}
void CuttlefishConfig::set_rootcanal_test_port(int rootcanal_test_port) {
  (*dictionary_)[kRootcanalTestPort] = rootcanal_test_port;
}

static constexpr char kRootcanalConfigFile[] = "rootcanal_config_file";
std::string CuttlefishConfig::rootcanal_config_file() const {
  return (*dictionary_)[kRootcanalConfigFile].asString();
}
void CuttlefishConfig::set_rootcanal_config_file(
    const std::string& rootcanal_config_file) {
  (*dictionary_)[kRootcanalConfigFile] =
      DefaultHostArtifactsPath(rootcanal_config_file);
}

static constexpr char kRootcanalDefaultCommandsFile[] =
    "rootcanal_default_commands_file";
std::string CuttlefishConfig::rootcanal_default_commands_file() const {
  return (*dictionary_)[kRootcanalDefaultCommandsFile].asString();
}
void CuttlefishConfig::set_rootcanal_default_commands_file(
    const std::string& rootcanal_default_commands_file) {
  (*dictionary_)[kRootcanalDefaultCommandsFile] =
      DefaultHostArtifactsPath(rootcanal_default_commands_file);
}

/*static*/ CuttlefishConfig* CuttlefishConfig::BuildConfigImpl(
    const std::string& path) {
  auto ret = new CuttlefishConfig();
  if (ret) {
    auto loaded = ret->LoadFromFile(path.c_str());
    if (!loaded) {
      delete ret;
      return nullptr;
    }
  }
  return ret;
}

/*static*/ std::unique_ptr<const CuttlefishConfig>
CuttlefishConfig::GetFromFile(const std::string& path) {
  return std::unique_ptr<const CuttlefishConfig>(BuildConfigImpl(path));
}

// Creates the (initially empty) config object and populates it with values from
// the config file if the CUTTLEFISH_CONFIG_FILE env variable is present.
// Returns nullptr if there was an error loading from file
/*static*/ const CuttlefishConfig* CuttlefishConfig::Get() {
  auto config_file_path =
      StringFromEnv(kCuttlefishConfigEnvVarName, GetGlobalConfigFileLink());
  static std::shared_ptr<CuttlefishConfig> config(
      BuildConfigImpl(config_file_path));
  return config.get();
}

/*static*/ bool CuttlefishConfig::ConfigExists() {
  auto config_file_path = StringFromEnv(kCuttlefishConfigEnvVarName,
                                        GetGlobalConfigFileLink());
  auto real_file_path = AbsolutePath(config_file_path.c_str());
  return FileExists(real_file_path);
}

CuttlefishConfig::CuttlefishConfig() : dictionary_(new Json::Value()) {}
// Can't use '= default' on the header because the compiler complains of
// Json::Value being an incomplete type
CuttlefishConfig::~CuttlefishConfig() = default;

CuttlefishConfig::CuttlefishConfig(CuttlefishConfig&&) = default;
CuttlefishConfig& CuttlefishConfig::operator=(CuttlefishConfig&&) = default;

bool CuttlefishConfig::LoadFromFile(const char* file) {
  auto real_file_path = AbsolutePath(file);
  if (real_file_path.empty()) {
    LOG(ERROR) << "Could not get real path for file " << file;
    return false;
  }
  Json::CharReaderBuilder builder;
  std::ifstream ifs(real_file_path);
  std::string errorMessage;
  if (!Json::parseFromStream(builder, ifs, dictionary_.get(), &errorMessage)) {
    LOG(ERROR) << "Could not read config file " << file << ": " << errorMessage;
    return false;
  }
  return true;
}
bool CuttlefishConfig::SaveToFile(const std::string& file) const {
  std::ofstream ofs(file);
  if (!ofs.is_open()) {
    LOG(ERROR) << "Unable to write to file " << file;
    return false;
  }
  ofs << *dictionary_;
  return !ofs.fail();
}

std::string CuttlefishConfig::instances_dir() const {
  return AbsolutePath(root_dir() + "/instances");
}

std::string CuttlefishConfig::InstancesPath(
    const std::string& file_name) const {
  return AbsolutePath(instances_dir() + "/" + file_name);
}

std::string CuttlefishConfig::assembly_dir() const {
  return AbsolutePath(root_dir() + "/assembly");
}

std::string CuttlefishConfig::AssemblyPath(
    const std::string& file_name) const {
  return AbsolutePath(assembly_dir() + "/" + file_name);
}

std::string CuttlefishConfig::instances_uds_dir() const {
  // Try to use /tmp/cf_avd_{uid}/ for UDS directory.
  // If it fails, use HOME directory(legacy) instead.

  auto defaultPath = AbsolutePath("/tmp/cf_avd_" + std::to_string(getuid()));

  if (!DirectoryExists(defaultPath) ||
      CanAccess(defaultPath, R_OK | W_OK | X_OK)) {
    return defaultPath;
  }

  return instances_dir();
}

std::string CuttlefishConfig::InstancesUdsPath(
    const std::string& file_name) const {
  return AbsolutePath(instances_uds_dir() + "/" + file_name);
}

CuttlefishConfig::MutableInstanceSpecific CuttlefishConfig::ForInstance(int num) {
  return MutableInstanceSpecific(this, std::to_string(num));
}

CuttlefishConfig::InstanceSpecific CuttlefishConfig::ForInstance(int num) const {
  return InstanceSpecific(this, std::to_string(num));
}

CuttlefishConfig::InstanceSpecific CuttlefishConfig::ForInstanceName(
    const std::string& name) const {
  return ForInstance(InstanceFromString(name));
}

CuttlefishConfig::InstanceSpecific CuttlefishConfig::ForDefaultInstance() const {
  return ForInstance(GetInstance());
}

std::vector<CuttlefishConfig::InstanceSpecific> CuttlefishConfig::Instances() const {
  const auto& json = (*dictionary_)[kInstances];
  std::vector<CuttlefishConfig::InstanceSpecific> instances;
  for (const auto& name : json.getMemberNames()) {
    instances.push_back(CuttlefishConfig::InstanceSpecific(this, name));
  }
  return instances;
}

std::vector<std::string> CuttlefishConfig::instance_dirs() const {
  std::vector<std::string> result;
  for (const auto& instance : Instances()) {
    result.push_back(instance.instance_dir());
    result.push_back(instance.instance_uds_dir());
  }
  return result;
}

static constexpr char kInstanceNames[] = "instance_names";
void CuttlefishConfig::set_instance_names(
    const std::vector<std::string>& instance_names) {
  Json::Value args_json_obj(Json::arrayValue);
  for (const auto& name : instance_names) {
    args_json_obj.append(name);
  }
  (*dictionary_)[kInstanceNames] = args_json_obj;
}
std::vector<std::string> CuttlefishConfig::instance_names() const {
  // NOTE: The structure of this field needs to remain stable, since
  // cvd_server may call this on config JSON files from various builds.
  //
  // This info is duplicated into its own field here so it is simpler
  // to keep stable, rather than parsing from Instances()::instance_name.
  //
  // Any non-stable changes must be accompanied by an uprev to the
  // cvd_server major version.
  std::vector<std::string> names;
  for (const Json::Value& name : (*dictionary_)[kInstanceNames]) {
    names.push_back(name.asString());
  }
  return names;
}

int GetInstance() {
  static int instance_id = InstanceFromEnvironment();
  return instance_id;
}

int GetDefaultVsockCid() {
  // we assume that this function is used to configure CuttlefishConfig once
  static const int default_vsock_cid = 3 + GetInstance() - 1;
  return default_vsock_cid;
}

int GetVsockServerPort(const int base,
                       const int vsock_guest_cid /**< per instance guest cid */) {
    return base + (vsock_guest_cid - 3);
}

std::string GetGlobalConfigFileLink() {
  return StringFromEnv("HOME", ".") + "/.cuttlefish_config.json";
}

std::string ForCurrentInstance(const char* prefix) {
  std::ostringstream stream;
  stream << prefix << std::setfill('0') << std::setw(2) << GetInstance();
  return stream.str();
}
int ForCurrentInstance(int base) { return base + GetInstance() - 1; }

std::string RandomSerialNumber(const std::string& prefix) {
  const char hex_characters[] = "0123456789ABCDEF";
  std::srand(time(0));
  char str[10];
  for(int i=0; i<10; i++){
    str[i] = hex_characters[rand() % strlen(hex_characters)];
  }
  return prefix + str;
}

std::string DefaultHostArtifactsPath(const std::string& file_name) {
  return (StringFromEnv("ANDROID_HOST_OUT", StringFromEnv("HOME", ".")) + "/") +
         file_name;
}

std::string HostBinaryPath(const std::string& binary_name) {
#ifdef __ANDROID__
  return binary_name;
#else
  return DefaultHostArtifactsPath("bin/" + binary_name);
#endif
}

std::string DefaultGuestImagePath(const std::string& file_name) {
  return (StringFromEnv("ANDROID_PRODUCT_OUT", StringFromEnv("HOME", "."))) +
         file_name;
}

bool HostSupportsQemuCli() {
  static bool supported =
      std::system(
          "/usr/lib/cuttlefish-common/bin/capability_query.py qemu_cli") == 0;
  return supported;
}

}  // namespace cuttlefish