omaha_request_builder_xml.cc - SHIFTPHONES/android_system_update_engine - Gitiles

 //
 // Copyright (C) 2019 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 "update_engine/omaha_request_builder_xml.h"

 #include <inttypes.h>

 #include <string>

 #include <base/guid.h>
 #include <base/logging.h>
 #include <base/strings/string_number_conversions.h>
 #include <base/strings/string_util.h>
 #include <base/strings/stringprintf.h>
 #include <base/time/time.h>

 #include "update_engine/common/constants.h"
 #include "update_engine/common/prefs_interface.h"
 #include "update_engine/common/utils.h"
 #include "update_engine/omaha_request_params.h"

 using std::string;

 namespace chromeos_update_engine {

 const int kNeverPinged = -1;

 bool XmlEncode(const string& input, string* output) {
   if (std::find_if(input.begin(), input.end(), [](const char c) {
         return c & 0x80;
       }) != input.end()) {
     LOG(WARNING) << "Invalid ASCII-7 string passed to the XML encoder:";
     utils::HexDumpString(input);
     return false;
   }
   output->clear();
   // We need at least input.size() space in the output, but the code below will
   // handle it if we need more.
   output->reserve(input.size());
   for (char c : input) {
     switch (c) {
       case '\"':
         output->append("&quot;");
         break;
       case '\'':
         output->append("&apos;");
         break;
       case '&':
         output->append("&amp;");
         break;
       case '<':
         output->append("&lt;");
         break;
       case '>':
         output->append("&gt;");
         break;
       default:
         output->push_back(c);
     }
   }
   return true;
 }

 string XmlEncodeWithDefault(const string& input, const string& default_value) {
   string output;
   if (XmlEncode(input, &output))
     return output;
   return default_value;
 }

 string OmahaRequestBuilderXml::GetPing() const {
   // Returns an XML ping element attribute assignment with attribute
   // |name| and value |ping_days| if |ping_days| has a value that needs
   // to be sent, or an empty string otherwise.
   auto GetPingAttribute = [](const char* name, int ping_days) -> string {
     if (ping_days > 0 || ping_days == kNeverPinged)
       return base::StringPrintf(" %s=\"%d\"", name, ping_days);
     return "";
   };

   string ping_active = GetPingAttribute("a", ping_active_days_);
   string ping_roll_call = GetPingAttribute("r", ping_roll_call_days_);
   if (!ping_active.empty() || !ping_roll_call.empty()) {
     return base::StringPrintf("        <ping active=\"1\"%s%s></ping>\n",
                               ping_active.c_str(),
                               ping_roll_call.c_str());
   }
   return "";
 }

 string OmahaRequestBuilderXml::GetAppBody(bool skip_updatecheck) const {
   string app_body;
   if (event_ == nullptr) {
     if (include_ping_)
       app_body = GetPing();
     if (!ping_only_) {
       if (!skip_updatecheck) {
         app_body += "        <updatecheck";
         if (!params_->target_version_prefix().empty()) {
           app_body += base::StringPrintf(
               " targetversionprefix=\"%s\"",
               XmlEncodeWithDefault(params_->target_version_prefix()).c_str());
           // Rollback requires target_version_prefix set.
           if (params_->rollback_allowed()) {
             app_body += " rollback_allowed=\"true\"";
           }
         }
         string autoupdate_token = params_->autoupdate_token();
         if (!autoupdate_token.empty()) {
           app_body += base::StringPrintf(
               " token=\"%s\"", XmlEncodeWithDefault(autoupdate_token).c_str());
         }

         app_body += "></updatecheck>\n";
       }

       // If this is the first update check after a reboot following a previous
       // update, generate an event containing the previous version number. If
       // the previous version preference file doesn't exist the event is still
       // generated with a previous version of 0.0.0.0 -- this is relevant for
       // older clients or new installs. The previous version event is not sent
       // for ping-only requests because they come before the client has
       // rebooted. The previous version event is also not sent if it was already
       // sent for this new version with a previous updatecheck.
       string prev_version;
       if (!prefs_->GetString(kPrefsPreviousVersion, &prev_version)) {
         prev_version = "0.0.0.0";
       }
       // We only store a non-empty previous version value after a successful
       // update in the previous boot. After reporting it back to the server,
       // we clear the previous version value so it doesn't get reported again.
       if (!prev_version.empty()) {
         app_body += base::StringPrintf(
             "        <event eventtype=\"%d\" eventresult=\"%d\" "
             "previousversion=\"%s\"></event>\n",
             OmahaEvent::kTypeRebootedAfterUpdate,
             OmahaEvent::kResultSuccess,
             XmlEncodeWithDefault(prev_version, "0.0.0.0").c_str());
         LOG_IF(WARNING, !prefs_->SetString(kPrefsPreviousVersion, ""))
             << "Unable to reset the previous version.";
       }
     }
   } else {
     // The error code is an optional attribute so append it only if the result
     // is not success.
     string error_code;
     if (event_->result != OmahaEvent::kResultSuccess) {
       error_code = base::StringPrintf(" errorcode=\"%d\"",
                                       static_cast<int>(event_->error_code));
     }
     app_body = base::StringPrintf(
         "        <event eventtype=\"%d\" eventresult=\"%d\"%s></event>\n",
         event_->type,
         event_->result,
         error_code.c_str());
   }

   return app_body;
 }

 string OmahaRequestBuilderXml::GetCohortArg(const string arg_name,
                                             const string prefs_key) const {
   // There's nothing wrong with not having a given cohort setting, so we check
   // existence first to avoid the warning log message.
   if (!prefs_->Exists(prefs_key))
     return "";
   string cohort_value;
   if (!prefs_->GetString(prefs_key, &cohort_value) || cohort_value.empty())
     return "";
   // This is a sanity check to avoid sending a huge XML file back to Ohama due
   // to a compromised stateful partition making the update check fail in low
   // network environments envent after a reboot.
   if (cohort_value.size() > 1024) {
     LOG(WARNING) << "The omaha cohort setting " << arg_name
                  << " has a too big value, which must be an error or an "
                     "attacker trying to inhibit updates.";
     return "";
   }

   string escaped_xml_value;
   if (!XmlEncode(cohort_value, &escaped_xml_value)) {
     LOG(WARNING) << "The omaha cohort setting " << arg_name
                  << " is ASCII-7 invalid, ignoring it.";
     return "";
   }

   return base::StringPrintf(
       "%s=\"%s\" ", arg_name.c_str(), escaped_xml_value.c_str());
 }

 bool IsValidComponentID(const string& id) {
   for (char c : id) {
     if (!isalnum(c) && c != '-' && c != '_' && c != '.')
       return false;
   }
   return true;
 }

 string OmahaRequestBuilderXml::GetApp(const OmahaAppData& app_data) const {
   string app_body = GetAppBody(app_data.skip_update);
   string app_versions;

   // If we are downgrading to a more stable channel and we are allowed to do
   // powerwash, then pass 0.0.0.0 as the version. This is needed to get the
   // highest-versioned payload on the destination channel.
   if (params_->ShouldPowerwash()) {
     LOG(INFO) << "Passing OS version as 0.0.0.0 as we are set to powerwash "
               << "on downgrading to the version in the more stable channel";
     app_versions = "version=\"0.0.0.0\" from_version=\"" +
                    XmlEncodeWithDefault(app_data.version, "0.0.0.0") + "\" ";
   } else {
     app_versions = "version=\"" +
                    XmlEncodeWithDefault(app_data.version, "0.0.0.0") + "\" ";
   }

   string download_channel = params_->download_channel();
   string app_channels =
       "track=\"" + XmlEncodeWithDefault(download_channel) + "\" ";
   if (params_->current_channel() != download_channel) {
     app_channels += "from_track=\"" +
                     XmlEncodeWithDefault(params_->current_channel()) + "\" ";
   }

   string delta_okay_str = params_->delta_okay() ? "true" : "false";

   // If install_date_days is not set (e.g. its value is -1 ), don't
   // include the attribute.
   string install_date_in_days_str = "";
   if (install_date_in_days_ >= 0) {
     install_date_in_days_str =
         base::StringPrintf("installdate=\"%d\" ", install_date_in_days_);
   }

   string app_cohort_args;
   app_cohort_args += GetCohortArg("cohort", kPrefsOmahaCohort);
   app_cohort_args += GetCohortArg("cohorthint", kPrefsOmahaCohortHint);
   app_cohort_args += GetCohortArg("cohortname", kPrefsOmahaCohortName);

   string fingerprint_arg;
   if (!params_->os_build_fingerprint().empty()) {
     fingerprint_arg = "fingerprint=\"" +
                       XmlEncodeWithDefault(params_->os_build_fingerprint()) +
                       "\" ";
   }

   string buildtype_arg;
   if (!params_->os_build_type().empty()) {
     buildtype_arg = "os_build_type=\"" +
                     XmlEncodeWithDefault(params_->os_build_type()) + "\" ";
   }

   string product_components_args;
   if (!params_->ShouldPowerwash() && !app_data.product_components.empty()) {
     brillo::KeyValueStore store;
     if (store.LoadFromString(app_data.product_components)) {
       for (const string& key : store.GetKeys()) {
         if (!IsValidComponentID(key)) {
           LOG(ERROR) << "Invalid component id: " << key;
           continue;
         }
         string version;
         if (!store.GetString(key, &version)) {
           LOG(ERROR) << "Failed to get version for " << key
                      << " in product_components.";
           continue;
         }
         product_components_args +=
             base::StringPrintf("_%s.version=\"%s\" ",
                                key.c_str(),
                                XmlEncodeWithDefault(version).c_str());
       }
     } else {
       LOG(ERROR) << "Failed to parse product_components:\n"
                  << app_data.product_components;
     }
   }

   string requisition_arg;
   if (!params_->device_requisition().empty()) {
     requisition_arg = "requisition=\"" +
                       XmlEncodeWithDefault(params_->device_requisition()) +
                       "\" ";
   }

   // clang-format off
   string app_xml = "    <app "
       "appid=\"" + XmlEncodeWithDefault(app_data.id) + "\" " +
       app_cohort_args +
       app_versions +
       app_channels +
       product_components_args +
       fingerprint_arg +
       buildtype_arg +
       "lang=\"" + XmlEncodeWithDefault(params_->app_lang(), "en-US") + "\" " +
       "board=\"" + XmlEncodeWithDefault(params_->os_board()) + "\" " +
       "hardware_class=\"" + XmlEncodeWithDefault(params_->hwid()) + "\" " +
       "delta_okay=\"" + delta_okay_str + "\" "
       "fw_version=\"" + XmlEncodeWithDefault(params_->fw_version()) + "\" " +
       "ec_version=\"" + XmlEncodeWithDefault(params_->ec_version()) + "\" " +
       install_date_in_days_str +
       requisition_arg +
       ">\n" +
          app_body +
       "    </app>\n";
   // clang-format on
   return app_xml;
 }

 string OmahaRequestBuilderXml::GetOs() const {
   string os_xml =
       "    <os "
       "version=\"" +
       XmlEncodeWithDefault(params_->os_version()) + "\" " + "platform=\"" +
       XmlEncodeWithDefault(params_->os_platform()) + "\" " + "sp=\"" +
       XmlEncodeWithDefault(params_->os_sp()) +
       "\">"
       "</os>\n";
   return os_xml;
 }

 string OmahaRequestBuilderXml::GetRequest() const {
   string os_xml = GetOs();
   string app_xml = GetApps();

   string request_xml = base::StringPrintf(
       "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
       "<request requestid=\"%s\" sessionid=\"%s\""
       " protocol=\"3.0\" updater=\"%s\" updaterversion=\"%s\""
       " installsource=\"%s\" ismachine=\"1\">\n%s%s</request>\n",
       base::GenerateGUID().c_str() /* requestid */,
       session_id_.c_str(),
       constants::kOmahaUpdaterID,
       kOmahaUpdaterVersion,
       params_->interactive() ? "ondemandupdate" : "scheduler",
       os_xml.c_str(),
       app_xml.c_str());

   return request_xml;
 }

 string OmahaRequestBuilderXml::GetApps() const {
   string app_xml = "";
   OmahaAppData product_app = {
       .id = params_->GetAppId(),
       .version = params_->app_version(),
       .product_components = params_->product_components(),
       // Skips updatecheck for platform app in case of an install operation.
       .skip_update = params_->is_install()};
   app_xml += GetApp(product_app);
   if (!params_->system_app_id().empty()) {
     OmahaAppData system_app = {.id = params_->system_app_id(),
                                .version = params_->system_version(),
                                .skip_update = false};
     app_xml += GetApp(system_app);
   }
   // Create APP ID according to |dlc_module_id| (sticking the current AppID to
   // the DLC module ID with an underscode).
   for (const auto& dlc_module_id : params_->dlc_module_ids()) {
     OmahaAppData dlc_module_app = {
         .id = params_->GetAppId() + "_" + dlc_module_id,
         .version = params_->app_version(),
         .skip_update = false};
     app_xml += GetApp(dlc_module_app);
   }
   return app_xml;
 }

 }  // namespace chromeos_update_engine
	//
	// Copyright (C) 2019 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 "update_engine/omaha_request_builder_xml.h"

	#include <inttypes.h>

	#include <string>

	#include <base/guid.h>
	#include <base/logging.h>
	#include <base/strings/string_number_conversions.h>
	#include <base/strings/string_util.h>
	#include <base/strings/stringprintf.h>
	#include <base/time/time.h>

	#include "update_engine/common/constants.h"
	#include "update_engine/common/prefs_interface.h"
	#include "update_engine/common/utils.h"
	#include "update_engine/omaha_request_params.h"

	using std::string;

	namespace chromeos_update_engine {

	const int kNeverPinged = -1;

	bool XmlEncode(const string& input, string* output) {
	if (std::find_if(input.begin(), input.end(), [](const char c) {
	return c & 0x80;
	}) != input.end()) {
	LOG(WARNING) << "Invalid ASCII-7 string passed to the XML encoder:";
	utils::HexDumpString(input);
	return false;
	}
	output->clear();
	// We need at least input.size() space in the output, but the code below will
	// handle it if we need more.
	output->reserve(input.size());
	for (char c : input) {
	switch (c) {
	case '\"':
	output->append(""");
	break;
	case '\'':
	output->append("'");
	break;
	case '&':
	output->append("&");
	break;
	case '<':
	output->append("<");
	break;
	case '>':
	output->append(">");
	break;
	default:
	output->push_back(c);
	}
	}
	return true;
	}

	string XmlEncodeWithDefault(const string& input, const string& default_value) {
	string output;
	if (XmlEncode(input, &output))
	return output;
	return default_value;
	}

	string OmahaRequestBuilderXml::GetPing() const {
	// Returns an XML ping element attribute assignment with attribute
	// \|name\| and value \|ping_days\| if \|ping_days\| has a value that needs
	// to be sent, or an empty string otherwise.
	auto GetPingAttribute = [](const char* name, int ping_days) -> string {
	if (ping_days > 0 \|\| ping_days == kNeverPinged)
	return base::StringPrintf(" %s=\"%d\"", name, ping_days);
	return "";
	};

	string ping_active = GetPingAttribute("a", ping_active_days_);
	string ping_roll_call = GetPingAttribute("r", ping_roll_call_days_);
	if (!ping_active.empty() \|\| !ping_roll_call.empty()) {
	return base::StringPrintf(" <ping active=\"1\"%s%s></ping>\n",
	ping_active.c_str(),
	ping_roll_call.c_str());
	}
	return "";
	}

	string OmahaRequestBuilderXml::GetAppBody(bool skip_updatecheck) const {
	string app_body;
	if (event_ == nullptr) {
	if (include_ping_)
	app_body = GetPing();
	if (!ping_only_) {
	if (!skip_updatecheck) {
	app_body += " <updatecheck";
	if (!params_->target_version_prefix().empty()) {
	app_body += base::StringPrintf(
	" targetversionprefix=\"%s\"",
	XmlEncodeWithDefault(params_->target_version_prefix()).c_str());
	// Rollback requires target_version_prefix set.
	if (params_->rollback_allowed()) {
	app_body += " rollback_allowed=\"true\"";
	}
	}
	string autoupdate_token = params_->autoupdate_token();
	if (!autoupdate_token.empty()) {
	app_body += base::StringPrintf(
	" token=\"%s\"", XmlEncodeWithDefault(autoupdate_token).c_str());
	}

	app_body += "></updatecheck>\n";
	}

	// If this is the first update check after a reboot following a previous
	// update, generate an event containing the previous version number. If
	// the previous version preference file doesn't exist the event is still
	// generated with a previous version of 0.0.0.0 -- this is relevant for
	// older clients or new installs. The previous version event is not sent
	// for ping-only requests because they come before the client has
	// rebooted. The previous version event is also not sent if it was already
	// sent for this new version with a previous updatecheck.
	string prev_version;
	if (!prefs_->GetString(kPrefsPreviousVersion, &prev_version)) {
	prev_version = "0.0.0.0";
	}
	// We only store a non-empty previous version value after a successful
	// update in the previous boot. After reporting it back to the server,
	// we clear the previous version value so it doesn't get reported again.
	if (!prev_version.empty()) {
	app_body += base::StringPrintf(
	" <event eventtype=\"%d\" eventresult=\"%d\" "
	"previousversion=\"%s\"></event>\n",
	OmahaEvent::kTypeRebootedAfterUpdate,
	OmahaEvent::kResultSuccess,
	XmlEncodeWithDefault(prev_version, "0.0.0.0").c_str());
	LOG_IF(WARNING, !prefs_->SetString(kPrefsPreviousVersion, ""))
	<< "Unable to reset the previous version.";
	}
	}
	} else {
	// The error code is an optional attribute so append it only if the result
	// is not success.
	string error_code;
	if (event_->result != OmahaEvent::kResultSuccess) {
	error_code = base::StringPrintf(" errorcode=\"%d\"",
	static_cast<int>(event_->error_code));
	}
	app_body = base::StringPrintf(
	" <event eventtype=\"%d\" eventresult=\"%d\"%s></event>\n",
	event_->type,
	event_->result,
	error_code.c_str());
	}

	return app_body;
	}

	string OmahaRequestBuilderXml::GetCohortArg(const string arg_name,
	const string prefs_key) const {
	// There's nothing wrong with not having a given cohort setting, so we check
	// existence first to avoid the warning log message.
	if (!prefs_->Exists(prefs_key))
	return "";
	string cohort_value;
	if (!prefs_->GetString(prefs_key, &cohort_value) \|\| cohort_value.empty())
	return "";
	// This is a sanity check to avoid sending a huge XML file back to Ohama due
	// to a compromised stateful partition making the update check fail in low
	// network environments envent after a reboot.
	if (cohort_value.size() > 1024) {
	LOG(WARNING) << "The omaha cohort setting " << arg_name
	<< " has a too big value, which must be an error or an "
	"attacker trying to inhibit updates.";
	return "";
	}

	string escaped_xml_value;
	if (!XmlEncode(cohort_value, &escaped_xml_value)) {
	LOG(WARNING) << "The omaha cohort setting " << arg_name
	<< " is ASCII-7 invalid, ignoring it.";
	return "";
	}

	return base::StringPrintf(
	"%s=\"%s\" ", arg_name.c_str(), escaped_xml_value.c_str());
	}

	bool IsValidComponentID(const string& id) {
	for (char c : id) {
	if (!isalnum(c) && c != '-' && c != '_' && c != '.')
	return false;
	}
	return true;
	}

	string OmahaRequestBuilderXml::GetApp(const OmahaAppData& app_data) const {
	string app_body = GetAppBody(app_data.skip_update);
	string app_versions;

	// If we are downgrading to a more stable channel and we are allowed to do
	// powerwash, then pass 0.0.0.0 as the version. This is needed to get the
	// highest-versioned payload on the destination channel.
	if (params_->ShouldPowerwash()) {
	LOG(INFO) << "Passing OS version as 0.0.0.0 as we are set to powerwash "
	<< "on downgrading to the version in the more stable channel";
	app_versions = "version=\"0.0.0.0\" from_version=\"" +
	XmlEncodeWithDefault(app_data.version, "0.0.0.0") + "\" ";
	} else {
	app_versions = "version=\"" +
	XmlEncodeWithDefault(app_data.version, "0.0.0.0") + "\" ";
	}

	string download_channel = params_->download_channel();
	string app_channels =
	"track=\"" + XmlEncodeWithDefault(download_channel) + "\" ";
	if (params_->current_channel() != download_channel) {
	app_channels += "from_track=\"" +
	XmlEncodeWithDefault(params_->current_channel()) + "\" ";
	}

	string delta_okay_str = params_->delta_okay() ? "true" : "false";

	// If install_date_days is not set (e.g. its value is -1 ), don't
	// include the attribute.
	string install_date_in_days_str = "";
	if (install_date_in_days_ >= 0) {
	install_date_in_days_str =
	base::StringPrintf("installdate=\"%d\" ", install_date_in_days_);
	}

	string app_cohort_args;
	app_cohort_args += GetCohortArg("cohort", kPrefsOmahaCohort);
	app_cohort_args += GetCohortArg("cohorthint", kPrefsOmahaCohortHint);
	app_cohort_args += GetCohortArg("cohortname", kPrefsOmahaCohortName);

	string fingerprint_arg;
	if (!params_->os_build_fingerprint().empty()) {
	fingerprint_arg = "fingerprint=\"" +
	XmlEncodeWithDefault(params_->os_build_fingerprint()) +
	"\" ";
	}

	string buildtype_arg;
	if (!params_->os_build_type().empty()) {
	buildtype_arg = "os_build_type=\"" +
	XmlEncodeWithDefault(params_->os_build_type()) + "\" ";
	}

	string product_components_args;
	if (!params_->ShouldPowerwash() && !app_data.product_components.empty()) {
	brillo::KeyValueStore store;
	if (store.LoadFromString(app_data.product_components)) {
	for (const string& key : store.GetKeys()) {
	if (!IsValidComponentID(key)) {
	LOG(ERROR) << "Invalid component id: " << key;
	continue;
	}
	string version;
	if (!store.GetString(key, &version)) {
	LOG(ERROR) << "Failed to get version for " << key
	<< " in product_components.";
	continue;
	}
	product_components_args +=
	base::StringPrintf("_%s.version=\"%s\" ",
	key.c_str(),
	XmlEncodeWithDefault(version).c_str());
	}
	} else {
	LOG(ERROR) << "Failed to parse product_components:\n"
	<< app_data.product_components;
	}
	}

	string requisition_arg;
	if (!params_->device_requisition().empty()) {
	requisition_arg = "requisition=\"" +
	XmlEncodeWithDefault(params_->device_requisition()) +
	"\" ";
	}

	// clang-format off
	string app_xml = " <app "
	"appid=\"" + XmlEncodeWithDefault(app_data.id) + "\" " +
	app_cohort_args +
	app_versions +
	app_channels +
	product_components_args +
	fingerprint_arg +
	buildtype_arg +
	"lang=\"" + XmlEncodeWithDefault(params_->app_lang(), "en-US") + "\" " +
	"board=\"" + XmlEncodeWithDefault(params_->os_board()) + "\" " +
	"hardware_class=\"" + XmlEncodeWithDefault(params_->hwid()) + "\" " +
	"delta_okay=\"" + delta_okay_str + "\" "
	"fw_version=\"" + XmlEncodeWithDefault(params_->fw_version()) + "\" " +
	"ec_version=\"" + XmlEncodeWithDefault(params_->ec_version()) + "\" " +
	install_date_in_days_str +
	requisition_arg +
	">\n" +
	app_body +
	" </app>\n";
	// clang-format on
	return app_xml;
	}

	string OmahaRequestBuilderXml::GetOs() const {
	string os_xml =
	" <os "
	"version=\"" +
	XmlEncodeWithDefault(params_->os_version()) + "\" " + "platform=\"" +
	XmlEncodeWithDefault(params_->os_platform()) + "\" " + "sp=\"" +
	XmlEncodeWithDefault(params_->os_sp()) +
	"\">"
	"</os>\n";
	return os_xml;
	}

	string OmahaRequestBuilderXml::GetRequest() const {
	string os_xml = GetOs();
	string app_xml = GetApps();

	string request_xml = base::StringPrintf(
	"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"
	"<request requestid=\"%s\" sessionid=\"%s\""
	" protocol=\"3.0\" updater=\"%s\" updaterversion=\"%s\""
	" installsource=\"%s\" ismachine=\"1\">\n%s%s</request>\n",
	base::GenerateGUID().c_str() /* requestid */,
	session_id_.c_str(),
	constants::kOmahaUpdaterID,
	kOmahaUpdaterVersion,
	params_->interactive() ? "ondemandupdate" : "scheduler",
	os_xml.c_str(),
	app_xml.c_str());

	return request_xml;
	}

	string OmahaRequestBuilderXml::GetApps() const {
	string app_xml = "";
	OmahaAppData product_app = {
	.id = params_->GetAppId(),
	.version = params_->app_version(),
	.product_components = params_->product_components(),
	// Skips updatecheck for platform app in case of an install operation.
	.skip_update = params_->is_install()};
	app_xml += GetApp(product_app);
	if (!params_->system_app_id().empty()) {
	OmahaAppData system_app = {.id = params_->system_app_id(),
	.version = params_->system_version(),
	.skip_update = false};
	app_xml += GetApp(system_app);
	}
	// Create APP ID according to \|dlc_module_id\| (sticking the current AppID to
	// the DLC module ID with an underscode).
	for (const auto& dlc_module_id : params_->dlc_module_ids()) {
	OmahaAppData dlc_module_app = {
	.id = params_->GetAppId() + "_" + dlc_module_id,
	.version = params_->app_version(),
	.skip_update = false};
	app_xml += GetApp(dlc_module_app);
	}
	return app_xml;
	}

	} // namespace chromeos_update_engine