libbinder: RpcSession - hide RPC address format
FAQ for this change.
- Why does RpcSession still have sendDecStrong(uint64_t)?
This is used by RpcState to send dec strongs on local (non-BpBinder)
binders. This is needed because if a client has the last strong ref
of a binder which is local to the corresponding server, the client
needs to transfer ownership of this binder to the server using the
call.
- Why is RpcSession::sendDecStrong(BpBinder) public?
It may be useful for testing, especially in situations where
~BpBinder would be hard to call.
- Why does BpBinder have a private accessor, but RpcState is friends
with some other Rpc* classes?
I would like to have as few friends as possible (in regards to C++
classes!), but it takes quite a bit of boilerplate to avoid this. I
want to avoid the Rpc stuff introspecting into the standard binder
stuff, but I'm not currently concerned about their interactions
between each other.
Bug: 167966510
Test: binderRpcTest
Change-Id: I89e4de2e3a042a4531e2fd41deeb9bab1c11ff94
diff --git a/libs/binder/BpBinder.cpp b/libs/binder/BpBinder.cpp
index 687ee25..92df874 100644
--- a/libs/binder/BpBinder.cpp
+++ b/libs/binder/BpBinder.cpp
@@ -510,7 +510,7 @@
{
ALOGV("onLastStrongRef BpBinder %p handle %d\n", this, binderHandle());
if (CC_UNLIKELY(isRpcBinder())) {
- (void)rpcSession()->sendDecStrong(rpcAddress());
+ (void)rpcSession()->sendDecStrong(this);
return;
}
IF_ALOGV() {
diff --git a/libs/binder/RpcSession.cpp b/libs/binder/RpcSession.cpp
index e8f984c..886a2e9 100644
--- a/libs/binder/RpcSession.cpp
+++ b/libs/binder/RpcSession.cpp
@@ -29,6 +29,7 @@
#include <android-base/hex.h>
#include <android-base/macros.h>
#include <android_runtime/vm.h>
+#include <binder/BpBinder.h>
#include <binder/Parcel.h>
#include <binder/RpcServer.h>
#include <binder/RpcTransportRaw.h>
@@ -226,6 +227,10 @@
sp<RpcSession>::fromExisting(this), reply, flags);
}
+status_t RpcSession::sendDecStrong(const BpBinder* binder) {
+ return sendDecStrong(binder->getPrivateAccessor().rpcAddress());
+}
+
status_t RpcSession::sendDecStrong(uint64_t address) {
ExclusiveConnection connection;
status_t status = ExclusiveConnection::find(sp<RpcSession>::fromExisting(this),
diff --git a/libs/binder/include/binder/BpBinder.h b/libs/binder/include/binder/BpBinder.h
index 7f56658..c0454b6 100644
--- a/libs/binder/include/binder/BpBinder.h
+++ b/libs/binder/include/binder/BpBinder.h
@@ -118,6 +118,7 @@
friend class BpBinder;
friend class ::android::Parcel;
friend class ::android::ProcessState;
+ friend class ::android::RpcSession;
friend class ::android::RpcState;
explicit PrivateAccessor(const BpBinder* binder) : mBinder(binder) {}
diff --git a/libs/binder/include/binder/RpcSession.h b/libs/binder/include/binder/RpcSession.h
index 9c7c970..a841079 100644
--- a/libs/binder/include/binder/RpcSession.h
+++ b/libs/binder/include/binder/RpcSession.h
@@ -153,7 +153,13 @@
[[nodiscard]] status_t transact(const sp<IBinder>& binder, uint32_t code, const Parcel& data,
Parcel* reply, uint32_t flags);
- [[nodiscard]] status_t sendDecStrong(uint64_t address);
+
+ /**
+ * Generally, you should not call this, unless you are testing error
+ * conditions, as this is called automatically by BpBinders when they are
+ * deleted (this is also why a raw pointer is used here)
+ */
+ [[nodiscard]] status_t sendDecStrong(const BpBinder* binder);
~RpcSession();
@@ -172,6 +178,8 @@
friend RpcState;
explicit RpcSession(std::unique_ptr<RpcTransportCtx> ctx);
+ [[nodiscard]] status_t sendDecStrong(uint64_t address);
+
class EventListener : public virtual RefBase {
public:
virtual void onSessionAllIncomingThreadsEnded(const sp<RpcSession>& session) = 0;