Check that ISystemSuspend is declared before acquiring a wake lock

On some systems (Minidroid & friends) there is no suspend-service, which
means that acquiring a wake lock would wait indefinitely. In our case
this prevented `adb bugreport` from working.

With this change if the service is not declared, acquire_wake_lock would
fail, as opposed to getting stuck.

Test: atest libpower_test
Test: block_suspend
  - works on aosp_cf_x86_64_phone-trunk_staging-userdebug
  - fails (expected) on aosp_cf_x86_64_minidroid-trunk_staging-userdebug

Bug: 291070376
Change-Id: Ie25f3d96e457aa7945f36c301e70b751d529e6c7

1 files changed, 9 insertions, 2 deletions

diff --git a/power.cpp b/power.cpp
index 98ce861..6041207 100644
--- a/power.cpp
+++ b/power.cpp
@@ -40,8 +40,15 @@ static std::unordered_map<std::string, std::shared_ptr<IWakeLock>> gWakeLockMap;
 
 static const std::shared_ptr<ISystemSuspend> getSystemSuspendServiceOnce() {
     static std::shared_ptr<ISystemSuspend> suspendService =
-        ISystemSuspend::fromBinder(ndk::SpAIBinder(AServiceManager_waitForService(
-            (ISystemSuspend::descriptor + std::string("/default")).c_str())));
+        []() -> std::shared_ptr<ISystemSuspend> {
+        std::string suspendServiceName =
+            ISystemSuspend::descriptor + std::string("/default");
+        if (!AServiceManager_isDeclared(suspendServiceName.c_str())) {
+            return nullptr;
+        }
+        return ISystemSuspend::fromBinder(ndk::SpAIBinder(
+            AServiceManager_waitForService(suspendServiceName.c_str())));
+    }();
     return suspendService;
 }