Allow a service to override another.

For instance, on vendor.img:
service foo /vendor/bin/nfc
    ...

And then on odm.img:
service foo /odm/bin/super-nfc
    override

Allows a service on ODM to override a HAL on vendor.

Bug: 69050941
Test: boot, init_tests
Change-Id: I4e908fb66e89fc6e021799fe1fa6603d3072d62a

init/init_test.cpp

@@ -25,6 +25,7 @@
 #include "import_parser.h"
 #include "keyword_map.h"
 #include "parser.h"
+#include "service.h"
 #include "test_function_map.h"
 #include "util.h"
 
@@ -34,12 +35,13 @@ namespace init {
 using ActionManagerCommand = std::function<void(ActionManager&)>;
 
 void TestInit(const std::string& init_script_file, const TestFunctionMap& test_function_map,
-              const std::vector<ActionManagerCommand>& commands) {
+              const std::vector<ActionManagerCommand>& commands, ServiceList* service_list) {
     ActionManager am;
 
     Action::set_function_map(&test_function_map);
 
     Parser parser;
+    parser.AddSectionParser("service", std::make_unique<ServiceParser>(service_list, nullptr));
     parser.AddSectionParser("on", std::make_unique<ActionParser>(&am, nullptr));
     parser.AddSectionParser("import", std::make_unique<ImportParser>(&parser));
 
@@ -55,11 +57,11 @@ void TestInit(const std::string& init_script_file, const TestFunctionMap& test_f
 }
 
 void TestInitText(const std::string& init_script, const TestFunctionMap& test_function_map,
-                  const std::vector<ActionManagerCommand>& commands) {
+                  const std::vector<ActionManagerCommand>& commands, ServiceList* service_list) {
     TemporaryFile tf;
     ASSERT_TRUE(tf.fd != -1);
     ASSERT_TRUE(android::base::WriteStringToFd(init_script, tf.fd));
-    TestInit(tf.path, test_function_map, commands);
+    TestInit(tf.path, test_function_map, commands, service_list);
 }
 
 TEST(init, SimpleEventTrigger) {
@@ -76,7 +78,8 @@ pass_test
     ActionManagerCommand trigger_boot = [](ActionManager& am) { am.QueueEventTrigger("boot"); };
     std::vector<ActionManagerCommand> commands{trigger_boot};
 
-    TestInitText(init_script, test_function_map, commands);
+    ServiceList service_list;
+    TestInitText(init_script, test_function_map, commands, &service_list);
 
     EXPECT_TRUE(expect_true);
 }
@@ -104,7 +107,30 @@ execute_third
     ActionManagerCommand trigger_boot = [](ActionManager& am) { am.QueueEventTrigger("boot"); };
     std::vector<ActionManagerCommand> commands{trigger_boot};
 
-    TestInitText(init_script, test_function_map, commands);
+    ServiceList service_list;
+    TestInitText(init_script, test_function_map, commands, &service_list);
+}
+
+TEST(init, OverrideService) {
+    std::string init_script = R"init(
+service A something
+    class first
+
+service A something
+    class second
+    override
+
+)init";
+
+    ServiceList service_list;
+    TestInitText(init_script, TestFunctionMap(), {}, &service_list);
+    ASSERT_EQ(1, std::distance(service_list.begin(), service_list.end()));
+
+    auto service = service_list.begin()->get();
+    ASSERT_NE(nullptr, service);
+    EXPECT_EQ(std::set<std::string>({"second"}), service->classnames());
+    EXPECT_EQ("A", service->name());
+    EXPECT_TRUE(service->is_override());
 }
 
 TEST(init, EventTriggerOrderMultipleFiles) {
@@ -162,7 +188,9 @@ TEST(init, EventTriggerOrderMultipleFiles) {
     ActionManagerCommand trigger_boot = [](ActionManager& am) { am.QueueEventTrigger("boot"); };
     std::vector<ActionManagerCommand> commands{trigger_boot};
 
-    TestInit(start.path, test_function_map, commands);
+    ServiceList service_list;
+
+    TestInit(start.path, test_function_map, commands, &service_list);
 
     EXPECT_EQ(6, num_executed);
 }

init/service.cpp

@@ -530,6 +530,11 @@ Result<Success> Service::ParseOomScoreAdjust(const std::vector<std::string>& arg
     return Success();
 }
 
+Result<Success> Service::ParseOverride(const std::vector<std::string>& args) {
+    override_ = true;
+    return Success();
+}
+
 Result<Success> Service::ParseMemcgSwappiness(const std::vector<std::string>& args) {
     if (!ParseInt(args[1], &swappiness_, 0)) {
         return Error() << "swappiness value must be equal or greater than 0";
@@ -671,6 +676,7 @@ const Service::OptionParserMap::Map& Service::OptionParserMap::map() const {
         {"keycodes",    {1,     kMax, &Service::ParseKeycodes}},
         {"oneshot",     {0,     0,    &Service::ParseOneshot}},
         {"onrestart",   {1,     kMax, &Service::ParseOnrestart}},
+        {"override",    {0,     0,    &Service::ParseOverride}},
         {"oom_score_adjust",
                         {1,     1,    &Service::ParseOomScoreAdjust}},
         {"memcg.swappiness",
@@ -1134,7 +1140,13 @@ Result<Success> ServiceParser::EndSection() {
     if (service_) {
         Service* old_service = service_list_->FindService(service_->name());
         if (old_service) {
-            return Error() << "ignored duplicate definition of service '" << service_->name() << "'";
+            if (!service_->is_override()) {
+                return Error() << "ignored duplicate definition of service '" << service_->name()
+                               << "'";
+            }
+
+            service_list_->RemoveService(*old_service);
+            old_service = nullptr;
         }
 
         service_list_->AddService(std::move(service_));

init/service.h

@@ -111,6 +111,7 @@ class Service {
     const std::set<std::string>& interfaces() const { return interfaces_; }
     int priority() const { return priority_; }
     int oom_score_adjust() const { return oom_score_adjust_; }
+    bool is_override() const { return override_; }
     bool process_cgroup_empty() const { return process_cgroup_empty_; }
     unsigned long start_order() const { return start_order_; }
     const std::vector<std::string>& args() const { return args_; }
@@ -139,6 +140,7 @@ class Service {
     Result<Success> ParseOneshot(const std::vector<std::string>& args);
     Result<Success> ParseOnrestart(const std::vector<std::string>& args);
     Result<Success> ParseOomScoreAdjust(const std::vector<std::string>& args);
+    Result<Success> ParseOverride(const std::vector<std::string>& args);
     Result<Success> ParseMemcgLimitInBytes(const std::vector<std::string>& args);
     Result<Success> ParseMemcgSoftLimitInBytes(const std::vector<std::string>& args);
     Result<Success> ParseMemcgSwappiness(const std::vector<std::string>& args);
@@ -201,6 +203,8 @@ class Service {
 
     bool process_cgroup_empty_ = false;
 
+    bool override_ = false;
+
     unsigned long start_order_;
 
     std::vector<std::pair<int, rlimit>> rlimits_;