Merge "Revive ACgroupController_getFlags LLNDK function to detect missing cgroups"
diff --git a/libprocessgroup/cgroup_map.cpp b/libprocessgroup/cgroup_map.cpp
index 20ae2be..2fc920b 100644
--- a/libprocessgroup/cgroup_map.cpp
+++ b/libprocessgroup/cgroup_map.cpp
@@ -71,7 +71,12 @@
     if (!HasValue()) return false;
 
     if (state_ == UNKNOWN) {
-        state_ = access(GetProcsFilePath("", 0, 0).c_str(), F_OK) == 0 ? USABLE : MISSING;
+        if (ACgroupController_getFlags != nullptr) {
+            uint32_t flags = ACgroupController_getFlags(controller_);
+            state_ = (flags & CGROUPRC_CONTROLLER_FLAG_MOUNTED) != 0 ? USABLE : MISSING;
+        } else {
+            state_ = access(GetProcsFilePath("", 0, 0).c_str(), F_OK) == 0 ? USABLE : MISSING;
+        }
     }
 
     return state_ == USABLE;
@@ -161,9 +166,16 @@
     auto controller_count = ACgroupFile_getControllerCount();
     for (uint32_t i = 0; i < controller_count; ++i) {
         const ACgroupController* controller = ACgroupFile_getController(i);
-        LOG(INFO) << "\t" << ACgroupController_getName(controller) << " ver "
-                  << ACgroupController_getVersion(controller) << " path "
-                  << ACgroupController_getPath(controller);
+        if (ACgroupController_getFlags != nullptr) {
+            LOG(INFO) << "\t" << ACgroupController_getName(controller) << " ver "
+                      << ACgroupController_getVersion(controller) << " path "
+                      << ACgroupController_getPath(controller) << " flags "
+                      << ACgroupController_getFlags(controller);
+        } else {
+            LOG(INFO) << "\t" << ACgroupController_getName(controller) << " ver "
+                      << ACgroupController_getVersion(controller) << " path "
+                      << ACgroupController_getPath(controller);
+        }
     }
 }
 
diff --git a/libprocessgroup/cgrouprc/cgroup_controller.cpp b/libprocessgroup/cgrouprc/cgroup_controller.cpp
index d064d31..5a326e5 100644
--- a/libprocessgroup/cgrouprc/cgroup_controller.cpp
+++ b/libprocessgroup/cgrouprc/cgroup_controller.cpp
@@ -27,6 +27,11 @@
     return controller->version();
 }
 
+uint32_t ACgroupController_getFlags(const ACgroupController* controller) {
+    CHECK(controller != nullptr);
+    return controller->flags();
+}
+
 const char* ACgroupController_getName(const ACgroupController* controller) {
     CHECK(controller != nullptr);
     return controller->name();
diff --git a/libprocessgroup/cgrouprc/include/android/cgrouprc.h b/libprocessgroup/cgrouprc/include/android/cgrouprc.h
index 0f6a9cd..0ce5123 100644
--- a/libprocessgroup/cgrouprc/include/android/cgrouprc.h
+++ b/libprocessgroup/cgrouprc/include/android/cgrouprc.h
@@ -66,10 +66,21 @@
         __INTRODUCED_IN(29);
 
 /**
- * Flag bitmask to be used when ACgroupController_getFlags can be exported
+ * Flag bitmask used in ACgroupController_getFlags
  */
 #define CGROUPRC_CONTROLLER_FLAG_MOUNTED 0x1
 
+#if __ANDROID_API__ >= __ANDROID_API_R__
+
+/**
+ * Returns the flags bitmask of the given controller.
+ * If the given controller is null, return 0.
+ */
+__attribute__((warn_unused_result, weak)) uint32_t ACgroupController_getFlags(
+        const ACgroupController*) __INTRODUCED_IN(30);
+
+#endif
+
 /**
  * Returns the name of the given controller.
  * If the given controller is null, return nullptr.
diff --git a/libprocessgroup/cgrouprc/libcgrouprc.llndk.txt b/libprocessgroup/cgrouprc/libcgrouprc.llndk.txt
index 91df392..ce5c419 100644
--- a/libprocessgroup/cgrouprc/libcgrouprc.llndk.txt
+++ b/libprocessgroup/cgrouprc/libcgrouprc.llndk.txt
@@ -9,3 +9,10 @@
   local:
     *;
 };
+
+LIBCGROUPRC_30 { # introduced=30
+  global:
+    ACgroupController_getFlags;
+  local:
+    *;
+};