Merge "Reland: "IPCThreadState: Add a public method to probe is a hwbinder called is being served.""android-o-mr1-iot-release-smart-display-r3android-o-mr1-iot-release-1.0.5oreo-mr1-1.2-iot-releasemaster-cuttlefish-testing-release

3 files changed, 44 insertions, 1 deletions

diff --git a/Android.bp b/Android.bp
index fee5417..f372618 100644
--- a/Android.bp
+++ b/Android.bp
@@ -23,6 +23,7 @@ cc_defaults {
         "liblog",
         "libcutils",
         "libutils",
+        "libbinderthreadstate",
     ],
     export_shared_lib_headers: [
         "libbase",
@@ -71,7 +72,7 @@ cc_library {
     defaults: [
         "libhwbinder_defaults",
         "hwbinder_pgo",
-        "hwbinder_lto"
+        "hwbinder_lto",
     ],
 }
 
@@ -95,6 +96,7 @@ cc_defaults {
         enable_profile_use: true,
     },
 }
+
 // Provide lto property to build hwbinder with LTO
 cc_defaults {
     name: "hwbinder_lto",
diff --git a/IPCThreadState.cpp b/IPCThreadState.cpp
index b275a7e..d97ad12 100644
--- a/IPCThreadState.cpp
+++ b/IPCThreadState.cpp
@@ -17,6 +17,7 @@
 #define LOG_TAG "hw-IPCThreadState"
 
 #include <hwbinder/IPCThreadState.h>
+#include <binderthreadstate/IPCThreadStateBase.h>
 
 #include <hwbinder/Binder.h>
 #include <hwbinder/BpHwBinder.h>
@@ -764,6 +765,7 @@ IPCThreadState::IPCThreadState()
 
     // TODO(b/67742352): remove this variable from the class
     (void)mMyThreadId;
+    mIPCThreadStateBase = IPCThreadStateBase::self();
 }
 
 IPCThreadState::~IPCThreadState()
@@ -1114,6 +1116,9 @@ status_t IPCThreadState::executeCommand(int32_t cmd)
                 "Not enough command data for brTRANSACTION");
             if (result != NO_ERROR) break;
 
+            // Record the fact that we're in a hwbinder call
+            mIPCThreadStateBase->pushCurrentState(
+                IPCThreadStateBase::CallState::HWBINDER);
             Parcel buffer;
             buffer.ipcSetDataReference(
                 reinterpret_cast<const uint8_t*>(tr.data.ptr.buffer),
@@ -1177,6 +1182,7 @@ status_t IPCThreadState::executeCommand(int32_t cmd)
                 error = mContextObject->transact(tr.code, buffer, &reply, tr.flags, reply_callback);
             }
 
+            mIPCThreadStateBase->popCurrentState();
             if ((tr.flags & TF_ONE_WAY) == 0) {
                 if (!reply_sent) {
                     // Should have been a reply but there wasn't, so there
@@ -1249,6 +1255,11 @@ status_t IPCThreadState::executeCommand(int32_t cmd)
     return result;
 }
 
+bool IPCThreadState::isServingCall() const
+{
+    return mIPCThreadStateBase->getCurrentBinderCallState() == IPCThreadStateBase::CallState::HWBINDER;
+}
+
 void IPCThreadState::threadDestructor(void *st)
 {
         IPCThreadState* const self = static_cast<IPCThreadState*>(st);
diff --git a/include/hwbinder/IPCThreadState.h b/include/hwbinder/IPCThreadState.h
index 28ae470..f2112c0 100644
--- a/include/hwbinder/IPCThreadState.h
+++ b/include/hwbinder/IPCThreadState.h
@@ -30,6 +30,9 @@ typedef  int  uid_t;
 
 // ---------------------------------------------------------------------------
 namespace android {
+
+class IPCThreadStateBase;
+
 namespace hardware {
 
 class IPCThreadState
@@ -95,6 +98,32 @@ public:
             bool                isLooperThread();
             bool                isOnlyBinderThread();
 
+            // Is this thread currently serving a hwbinder call. This method
+            // returns true if while traversing backwards from the function call
+            // stack for this thread, we encounter a function serving a hwbinder
+            // call before encountering a binder call / hitting the end of the
+            // call stack.
+            // Eg: If thread T1 went through the following call pattern
+            //     1) T1 receives and executes binder call B1.
+            //     2) While handling B1, T1 makes hwbinder call H1.
+            //     3) The handler of H1, calls into T1 with a callback H2.
+            // If isServingCall() is called during B1 before 3), this method
+            // will return false, else true.
+            //
+            //  ----
+            // | H2 | ---> While callback H2 is being handled during 3).
+            //  ----
+            // | B1 | ---> While B1 is being handled, hwbinder call H1 made.
+            //  ----
+            // Fig: Thread Call stack while handling H2.
+            //
+            // This is since after 3), while traversing the thread call stack,
+            // we hit a hwbinder call before a binder call / end of stack.
+            // This method may be typically used to determine whether to use
+            // hardware::IPCThreadState methods or IPCThreadState methods to
+            // infer information about thread state.
+            bool isServingCall() const;
+
             // Tasks which are done on the binder thread after the thread returns to the
             // threadpool.
             void addPostCommandTask(const std::function<void(void)>& task);
@@ -144,6 +173,7 @@ public:
             bool mIsPollingThread;
 
             std::vector<std::function<void(void)>> mPostCommandTasks;
+            IPCThreadStateBase *mIPCThreadStateBase;
 };
 
 }; // namespace hardware