1 // 2 // Copyright (C) 2014 The Android Open Source Project 3 // 4 // Licensed under the Apache License, Version 2.0 (the "License"); 5 // you may not use this file except in compliance with the License. 6 // You may obtain a copy of the License at 7 // 8 // http://www.apache.org/licenses/LICENSE-2.0 9 // 10 // Unless required by applicable law or agreed to in writing, software 11 // distributed under the License is distributed on an "AS IS" BASIS, 12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 // See the License for the specific language governing permissions and 14 // limitations under the License. 15 // 16 17 #ifndef UPDATE_ENGINE_UPDATE_MANAGER_DEFAULT_POLICY_H_ 18 #define UPDATE_ENGINE_UPDATE_MANAGER_DEFAULT_POLICY_H_ 19 20 #include <memory> 21 #include <string> 22 23 #include <base/time/time.h> 24 25 #include "update_engine/common/clock_interface.h" 26 #include "update_engine/update_manager/policy.h" 27 28 namespace chromeos_update_manager { 29 30 // Auxiliary state class for DefaultPolicy evaluations. 31 // 32 // IMPORTANT: The use of a state object in policies is generally forbidden, as 33 // it was a design decision to keep policy calls side-effect free. We make an 34 // exception here to ensure that DefaultPolicy indeed serves as a safe (and 35 // secure) fallback option. This practice should be avoided when imlpementing 36 // other policies. 37 class DefaultPolicyState { 38 public: DefaultPolicyState()39 DefaultPolicyState() {} 40 IsLastCheckAllowedTimeSet()41 bool IsLastCheckAllowedTimeSet() const { 42 return last_check_allowed_time_ != base::Time::Max(); 43 } 44 45 // Sets/returns the point time on the monotonic time scale when the latest 46 // check allowed was recorded. set_last_check_allowed_time(base::Time timestamp)47 void set_last_check_allowed_time(base::Time timestamp) { 48 last_check_allowed_time_ = timestamp; 49 } last_check_allowed_time()50 base::Time last_check_allowed_time() const { 51 return last_check_allowed_time_; 52 } 53 54 private: 55 base::Time last_check_allowed_time_ = base::Time::Max(); 56 }; 57 58 // The DefaultPolicy is a safe Policy implementation that doesn't fail. The 59 // values returned by this policy are safe default in case of failure of the 60 // actual policy being used by the UpdateManager. 61 class DefaultPolicy : public Policy { 62 public: 63 explicit DefaultPolicy(chromeos_update_engine::ClockInterface* clock); DefaultPolicy()64 DefaultPolicy() : DefaultPolicy(nullptr) {} ~DefaultPolicy()65 ~DefaultPolicy() override {} 66 67 // Policy overrides. 68 EvalStatus UpdateCheckAllowed(EvaluationContext* ec, 69 State* state, 70 std::string* error, 71 UpdateCheckParams* result) const override; 72 73 EvalStatus UpdateCanBeApplied( 74 EvaluationContext* ec, 75 State* state, 76 std::string* error, 77 chromeos_update_engine::ErrorCode* result, 78 chromeos_update_engine::InstallPlan* install_plan) const override; 79 80 EvalStatus UpdateCanStart(EvaluationContext* ec, 81 State* state, 82 std::string* error, 83 UpdateDownloadParams* result, 84 UpdateState update_state) const override; 85 86 EvalStatus UpdateDownloadAllowed(EvaluationContext* ec, 87 State* state, 88 std::string* error, 89 bool* result) const override; 90 91 EvalStatus P2PEnabled(EvaluationContext* ec, 92 State* state, 93 std::string* error, 94 bool* result) const override; 95 96 EvalStatus P2PEnabledChanged(EvaluationContext* ec, 97 State* state, 98 std::string* error, 99 bool* result, 100 bool prev_result) const override; 101 102 protected: 103 // Policy override. PolicyName()104 std::string PolicyName() const override { return "DefaultPolicy"; } 105 106 private: 107 // A clock interface. 108 chromeos_update_engine::ClockInterface* clock_; 109 110 // An auxiliary state object. 111 std::unique_ptr<DefaultPolicyState> aux_state_; 112 113 DISALLOW_COPY_AND_ASSIGN(DefaultPolicy); 114 }; 115 116 } // namespace chromeos_update_manager 117 118 #endif // UPDATE_ENGINE_UPDATE_MANAGER_DEFAULT_POLICY_H_ 119