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      1 /*
      2  * Copyright (C) 2018 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 #include "action_parser.h"
     18 
     19 #include <android-base/strings.h>
     20 
     21 #include "stable_properties.h"
     22 
     23 #if defined(__ANDROID__)
     24 #include <android-base/properties.h>
     25 #else
     26 #include "host_init_stubs.h"
     27 #endif
     28 
     29 using android::base::GetBoolProperty;
     30 using android::base::StartsWith;
     31 
     32 namespace android {
     33 namespace init {
     34 
     35 namespace {
     36 
     37 bool IsActionableProperty(Subcontext* subcontext, const std::string& prop_name) {
     38     static bool enabled = GetBoolProperty("ro.actionable_compatible_property.enabled", false);
     39 
     40     if (subcontext == nullptr || !enabled) {
     41         return true;
     42     }
     43 
     44     if (kExportedActionableProperties.count(prop_name) == 1) {
     45         return true;
     46     }
     47     for (const auto& prefix : kPartnerPrefixes) {
     48         if (android::base::StartsWith(prop_name, prefix)) {
     49             return true;
     50         }
     51     }
     52     return false;
     53 }
     54 
     55 Result<Success> ParsePropertyTrigger(const std::string& trigger, Subcontext* subcontext,
     56                                      std::map<std::string, std::string>* property_triggers) {
     57     const static std::string prop_str("property:");
     58     std::string prop_name(trigger.substr(prop_str.length()));
     59     size_t equal_pos = prop_name.find('=');
     60     if (equal_pos == std::string::npos) {
     61         return Error() << "property trigger found without matching '='";
     62     }
     63 
     64     std::string prop_value(prop_name.substr(equal_pos + 1));
     65     prop_name.erase(equal_pos);
     66 
     67     if (!IsActionableProperty(subcontext, prop_name)) {
     68         return Error() << "unexported property tigger found: " << prop_name;
     69     }
     70 
     71     if (auto [it, inserted] = property_triggers->emplace(prop_name, prop_value); !inserted) {
     72         return Error() << "multiple property triggers found for same property";
     73     }
     74     return Success();
     75 }
     76 
     77 Result<Success> ParseTriggers(const std::vector<std::string>& args, Subcontext* subcontext,
     78                               std::string* event_trigger,
     79                               std::map<std::string, std::string>* property_triggers) {
     80     const static std::string prop_str("property:");
     81     for (std::size_t i = 0; i < args.size(); ++i) {
     82         if (args[i].empty()) {
     83             return Error() << "empty trigger is not valid";
     84         }
     85 
     86         if (i % 2) {
     87             if (args[i] != "&&") {
     88                 return Error() << "&& is the only symbol allowed to concatenate actions";
     89             } else {
     90                 continue;
     91             }
     92         }
     93 
     94         if (!args[i].compare(0, prop_str.length(), prop_str)) {
     95             if (auto result = ParsePropertyTrigger(args[i], subcontext, property_triggers);
     96                 !result) {
     97                 return result;
     98             }
     99         } else {
    100             if (!event_trigger->empty()) {
    101                 return Error() << "multiple event triggers are not allowed";
    102             }
    103 
    104             *event_trigger = args[i];
    105         }
    106     }
    107 
    108     return Success();
    109 }
    110 
    111 }  // namespace
    112 
    113 Result<Success> ActionParser::ParseSection(std::vector<std::string>&& args,
    114                                            const std::string& filename, int line) {
    115     std::vector<std::string> triggers(args.begin() + 1, args.end());
    116     if (triggers.size() < 1) {
    117         return Error() << "Actions must have a trigger";
    118     }
    119 
    120     Subcontext* action_subcontext = nullptr;
    121     if (subcontexts_) {
    122         for (auto& subcontext : *subcontexts_) {
    123             if (StartsWith(filename, subcontext.path_prefix())) {
    124                 action_subcontext = &subcontext;
    125                 break;
    126             }
    127         }
    128     }
    129 
    130     std::string event_trigger;
    131     std::map<std::string, std::string> property_triggers;
    132 
    133     if (auto result = ParseTriggers(triggers, action_subcontext, &event_trigger, &property_triggers);
    134         !result) {
    135         return Error() << "ParseTriggers() failed: " << result.error();
    136     }
    137 
    138     auto action = std::make_unique<Action>(false, action_subcontext, filename, line, event_trigger,
    139                                            property_triggers);
    140 
    141     action_ = std::move(action);
    142     return Success();
    143 }
    144 
    145 Result<Success> ActionParser::ParseLineSection(std::vector<std::string>&& args, int line) {
    146     return action_ ? action_->AddCommand(std::move(args), line) : Success();
    147 }
    148 
    149 Result<Success> ActionParser::EndSection() {
    150     if (action_ && action_->NumCommands() > 0) {
    151         action_manager_->AddAction(std::move(action_));
    152     }
    153 
    154     return Success();
    155 }
    156 
    157 }  // namespace init
    158 }  // namespace android
    159