commit 39d887d308c0430a5046d7dfaec87dfaaea1a7aa
author Steven Moreland <smoreland@google.com> Fri Jan 31 14:56:45 2020 -0800
committer Steven Moreland <smoreland@google.com> Wed Feb 05 10:15:39 2020 -0800
tree ec5075cd89a63c7f73cfafe411bd0d2c1289406e
parent c02c9230ea8ac7cd9916053f6d49075989c1260a

Remove need for libbinderthreadstate.

Instead of having this library, libbinder/libhwbinder can keep track of
stack pointers so that when they recurse, we know which one was visited
most recently.

As with the original implementation of libbinderthreadstate, this is
somewhat of a hack. An explanation of why this is and what to do instead
is added in CallerUtils.h.

Bug: 148692216
Test: libbinderthreadstateutils_test
Change-Id: Ief28663728fb8786b06bf9e72238052b9af81d87
Merged-In: Ief28663728fb8786b06bf9e72238052b9af81d87

libs/binder/IPCThreadState.cpp

diff --git a/libs/binder/IPCThreadState.cpp b/libs/binder/IPCThreadState.cpp
index 4981d7a..4dcd07a 100644
--- a/libs/binder/IPCThreadState.cpp
+++ b/libs/binder/IPCThreadState.cpp
@@ -17,7 +17,6 @@
 #define LOG_TAG "IPCThreadState"
 
 #include <binder/IPCThreadState.h>
-#include <binderthreadstate/IPCThreadStateBase.h>
 
 #include <binder/Binder.h>
 #include <binder/BpBinder.h>
@@ -803,6 +802,7 @@
 
 IPCThreadState::IPCThreadState()
     : mProcess(ProcessState::self()),
+      mServingStackPointer(nullptr),
       mWorkSource(kUnsetWorkSource),
       mPropagateWorkSource(false),
       mStrictModePolicy(0),
@@ -813,7 +813,6 @@
     clearCaller();
     mIn.setDataCapacity(256);
     mOut.setDataCapacity(256);
-    mIPCThreadStateBase = IPCThreadStateBase::self();
 }
 
 IPCThreadState::~IPCThreadState()
@@ -1163,9 +1162,6 @@
                 "Not enough command data for brTRANSACTION");
             if (result != NO_ERROR) break;
 
-            //Record the fact that we're in a binder call.
-            mIPCThreadStateBase->pushCurrentState(
-                IPCThreadStateBase::CallState::BINDER);
             Parcel buffer;
             buffer.ipcSetDataReference(
                 reinterpret_cast<const uint8_t*>(tr.data.ptr.buffer),
@@ -1173,6 +1169,9 @@
                 reinterpret_cast<const binder_size_t*>(tr.data.ptr.offsets),
                 tr.offsets_size/sizeof(binder_size_t), freeBuffer, this);
 
+            const void* origServingStackPointer = mServingStackPointer;
+            mServingStackPointer = &origServingStackPointer; // anything on the stack
+
             const pid_t origPid = mCallingPid;
             const char* origSid = mCallingSid;
             const uid_t origUid = mCallingUid;
@@ -1223,7 +1222,6 @@
                 error = the_context_object->transact(tr.code, buffer, &reply, tr.flags);
             }
 
-            mIPCThreadStateBase->popCurrentState();
             //ALOGI("<<<< TRANSACT from pid %d restore pid %d sid %s uid %d\n",
             //     mCallingPid, origPid, (origSid ? origSid : "<N/A>"), origUid);
 
@@ -1235,6 +1233,7 @@
                 LOG_ONEWAY("NOT sending reply to %d!", mCallingPid);
             }
 
+            mServingStackPointer = origServingStackPointer;
             mCallingPid = origPid;
             mCallingSid = origSid;
             mCallingUid = origUid;
@@ -1290,8 +1289,8 @@
     return result;
 }
 
-bool IPCThreadState::isServingCall() const {
-    return mIPCThreadStateBase->getCurrentBinderCallState() == IPCThreadStateBase::CallState::BINDER;
+const void* IPCThreadState::getServingStackPointer() const {
+     return mServingStackPointer;
 }
 
 void IPCThreadState::threadDestructor(void *st)