omaha_request_builder_xml.h

//
// 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.
//

#ifndef UPDATE_ENGINE_OMAHA_REQUEST_BUILDER_XML_H_
#define UPDATE_ENGINE_OMAHA_REQUEST_BUILDER_XML_H_

#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>

#include <map>
#include <memory>
#include <string>
#include <vector>

#include <gtest/gtest_prod.h>  // for FRIEND_TEST

#include <brillo/secure_blob.h>
#include <curl/curl.h>

#include "update_engine/common/action.h"
#include "update_engine/common/http_fetcher.h"
#include "update_engine/omaha_response.h"
#include "update_engine/system_state.h"

namespace chromeos_update_engine {

extern const int kNeverPinged;

// This struct encapsulates the Omaha event information. For a
// complete list of defined event types and results, see
// http://code.google.com/p/omaha/wiki/ServerProtocol#event
struct OmahaEvent {
  // The Type values correspond to EVENT_TYPE values of Omaha.
  enum Type {
    kTypeUnknown = 0,
    kTypeDownloadComplete = 1,
    kTypeInstallComplete = 2,
    kTypeUpdateComplete = 3,
    kTypeUpdateDownloadStarted = 13,
    kTypeUpdateDownloadFinished = 14,
    // Chromium OS reserved type sent after the first reboot following an update
    // completed.
    kTypeRebootedAfterUpdate = 54,
  };

  // The Result values correspond to EVENT_RESULT values of Omaha.
  enum Result {
    kResultError = 0,
    kResultSuccess = 1,
    kResultUpdateDeferred = 9,  // When we ignore/defer updates due to policy.
  };

  OmahaEvent()
      : type(kTypeUnknown),
        result(kResultError),
        error_code(ErrorCode::kError) {}
  explicit OmahaEvent(Type in_type)
      : type(in_type),
        result(kResultSuccess),
        error_code(ErrorCode::kSuccess) {}
  OmahaEvent(Type in_type, Result in_result, ErrorCode in_error_code)
      : type(in_type), result(in_result), error_code(in_error_code) {}

  Type type;
  Result result;
  ErrorCode error_code;
};

struct OmahaAppData {
  std::string id;
  std::string version;
  std::string product_components;
  bool skip_update;
};

// Encodes XML entities in a given string. Input must be ASCII-7 valid. If
// the input is invalid, the default value is used instead.
std::string XmlEncodeWithDefault(const std::string& input,
                                 const std::string& default_value = "");

// Escapes text so it can be included as character data and attribute
// values. The |input| string must be valid ASCII-7, no UTF-8 supported.
// Returns whether the |input| was valid and escaped properly in |output|.
bool XmlEncode(const std::string& input, std::string* output);

// Returns a boolean based on examining each character on whether it's a valid
// component (meaning all characters are an alphanum excluding '-', '_', '.').
bool IsValidComponentID(const std::string& id);

class OmahaRequestBuilder {
 public:
  OmahaRequestBuilder() = default;
  virtual ~OmahaRequestBuilder() = default;

  virtual std::string GetRequest() const = 0;

 private:
  DISALLOW_COPY_AND_ASSIGN(OmahaRequestBuilder);
};

class OmahaRequestBuilderXml : OmahaRequestBuilder {
 public:
  OmahaRequestBuilderXml(const OmahaEvent* event,
                         OmahaRequestParams* params,
                         bool ping_only,
                         bool include_ping,
                         int ping_active_days,
                         int ping_roll_call_days,
                         int install_date_in_days,
                         PrefsInterface* prefs)
      : event_(event),
        params_(params),
        ping_only_(ping_only),
        include_ping_(include_ping),
        ping_active_days_(ping_active_days),
        ping_roll_call_days_(ping_roll_call_days),
        install_date_in_days_(install_date_in_days),
        prefs_(prefs) {}

  ~OmahaRequestBuilderXml() override = default;

  // Returns an XML that corresponds to the entire Omaha request.
  std::string GetRequest() const override;

 private:
  // Returns an XML that corresponds to the entire <os> node of the Omaha
  // request based on the member variables.
  std::string GetOs() const;

  // Returns an XML that corresponds to all <app> nodes of the Omaha
  // request based on the given parameters.
  std::string GetApps() const;

  // Returns an XML that corresponds to the single <app> node of the Omaha
  // request based on the given parameters.
  std::string GetApp(const OmahaAppData& app_data) const;

  // Returns an XML that goes into the body of the <app> element of the Omaha
  // request based on the given parameters.
  // The skip_updatecheck argument if set to true will omit the emission of
  // the updatecheck xml tag in the body of the <app> element.
  std::string GetAppBody(bool skip_updatecheck) const;

  // Returns the cohort* argument to include in the <app> tag for the passed
  // |arg_name| and |prefs_key|, if any. The return value is suitable to
  // concatenate to the list of arguments and includes a space at the end.
  std::string GetCohortArg(const std::string arg_name,
                           const std::string prefs_key) const;

  // Returns an XML ping element if any of the elapsed days need to be
  // sent, or an empty string otherwise.
  std::string GetPing() const;

  const OmahaEvent* event_;
  OmahaRequestParams* params_;
  bool ping_only_;
  bool include_ping_;
  int ping_active_days_;
  int ping_roll_call_days_;
  int install_date_in_days_;
  PrefsInterface* prefs_;

  DISALLOW_COPY_AND_ASSIGN(OmahaRequestBuilderXml);
};

}  // namespace chromeos_update_engine

#endif  // UPDATE_ENGINE_OMAHA_REQUEST_BUILDER_XML_H_