Add isHidlSupported API and use it

This is initially always going to return true until we have removed all
HIDL from Cuttlefish. Then it will be based on the vendor API level.

Test: remove kTempHidlSupport && m && launch_cvd
Bug: 218588089
Change-Id: Ic688df8bb0942e1aa8ba9bf5a34514083be1f2b4

2 files changed, 22 insertions, 11 deletions

diff --git a/transport/ServiceManagement.cpp b/transport/ServiceManagement.cpp
index 6d85b57..8c9bc5b 100644
--- a/transport/ServiceManagement.cpp
+++ b/transport/ServiceManagement.cpp
@@ -17,6 +17,7 @@
 #define LOG_TAG "HidlServiceManagement"
 
 #ifdef __ANDROID__
+#include <android/api-level.h>
 #include <android/dlext.h>
 #endif  // __ANDROID__
 
@@ -209,10 +210,21 @@ static bool isServiceManager(const hidl_string& fqName) {
     return fqName == IServiceManager1_0::descriptor || fqName == IServiceManager1_1::descriptor ||
            fqName == IServiceManager1_2::descriptor;
 }
-static bool isHwServiceManagerInstalled() {
-    return access("/system_ext/bin/hwservicemanager", F_OK) == 0 ||
-           access("/system/system_ext/bin/hwservicemanager", F_OK) == 0 ||
-           access("/system/bin/hwservicemanager", F_OK) == 0;
+
+bool isHidlSupported() {
+#ifdef __ANDROID__
+    // TODO(b/218588089) remove this temporary support variable once Cuttlefish
+    // (the only current Android V launching device) no longer requires HIDL.
+    constexpr bool kTempHidlSupport = true;
+    static const char* kVendorApiProperty = "ro.vendor.api_level";
+    // HIDL and hwservicemanager are not supported in Android V+
+    return android::base::GetIntProperty(kVendorApiProperty, 0) < __ANDROID_API_V__ ||
+           kTempHidlSupport;
+#else
+    // No access to properties and no requirement for dropping HIDL support if
+    // this isn't Android
+    return true;
+#endif  // __ANDROID__
 }
 
 /*
@@ -323,13 +335,9 @@ sp<IServiceManager1_2> defaultServiceManager1_2() {
             return gDefaultServiceManager;
         }
 
-        if (!isHwServiceManagerInstalled()) {
+        if (!isHidlSupported()) {
             // hwservicemanager is not available on this device.
-            LOG(WARNING)
-                    << "hwservicemanager is not installed on the device. If HIDL support "
-                    << "is still needed, hwservicemanager and android.hidl.allocator@1.0-service "
-                    << "need to be added to the device's PRODUCT_PACKAGES and the kernel config "
-                    << "needs to have 'hwbinder' in CONFIG_ANDROID_BINDER_DEVICES.";
+            LOG(WARNING) << "hwservicemanager is not supported on the device.";
             gDefaultServiceManager = sp<NoHwServiceManager>::make();
             return gDefaultServiceManager;
         }
@@ -533,7 +541,7 @@ struct PassthroughServiceManager : IServiceManager1_1 {
         // This is required to run without hwservicemanager while we have
         // passthrough HIDL services. Once the passthrough HIDL services have
         // been removed, the PassthroughServiceManager will no longer be needed.
-        if (!isHwServiceManagerInstalled() && isServiceManager(fqName)) {
+        if (!isHidlSupported() && isServiceManager(fqName)) {
             return defaultServiceManager1_2();
         }
 
diff --git a/transport/include/hidl/ServiceManagement.h b/transport/include/hidl/ServiceManagement.h
index 886e816..715f27e 100644
--- a/transport/include/hidl/ServiceManagement.h
+++ b/transport/include/hidl/ServiceManagement.h
@@ -70,6 +70,9 @@ status_t registerAsServiceInternal(const sp<::android::hidl::base::V1_0::IBase>&
                                    const std::string& name);
 }  // namespace details
 
+// Returns whether or not HIDL is supported on this device
+bool isHidlSupported();
+
 // These functions are for internal use by hidl. If you want to get ahold
 // of an interface, the best way to do this is by calling IFoo::getService()
 sp<::android::hidl::manager::V1_0::IServiceManager> defaultServiceManager();