commit 7c8dd48ffd8662146fe54dba5a3b7d8015fdc07d
author Tomasz Wasilczyk <twasilczyk@google.com> Thu Mar 23 15:30:03 2023 -0700
committer Tomasz Wasilczyk <twasilczyk@google.com> Thu May 11 11:38:30 2023 -0700
tree 00c19c0570525cfb1e86aebaa95e781eaa51c1d6
parent e66bfdb5f841d7153dc41a75e19c39c6ff7bac69

Fix publishing RPC Server on the same address/port after a short time

Bug: 274786956
Test: atest libsdvrpc_test_cpp

Change-Id: I58b0b99b5e3ab8c9659eed0eba9ff689000b84ac

libs/binder/RpcServer.cpp

diff --git a/libs/binder/RpcServer.cpp b/libs/binder/RpcServer.cpp
index 9282856..1635e2a 100644
--- a/libs/binder/RpcServer.cpp
+++ b/libs/binder/RpcServer.cpp
@@ -161,6 +161,12 @@
     mConnectionFilter = std::move(filter);
 }
 
+void RpcServer::setServerSocketModifier(std::function<void(base::borrowed_fd)>&& modifier) {
+    RpcMutexLockGuard _l(mLock);
+    LOG_ALWAYS_FATAL_IF(mServer.fd != -1, "Already started");
+    mServerSocketModifier = std::move(modifier);
+}
+
 sp<IBinder> RpcServer::getRootObject() {
     RpcMutexLockGuard _l(mLock);
     bool hasWeak = mRootObjectWeak.unsafe_get();
@@ -335,6 +341,8 @@
         mJoinThread.reset();
     }
 
+    mServer = RpcTransportFd();
+
     LOG_RPC_DETAIL("Finished waiting on shutdown.");
 
     mShutdownTrigger = nullptr;
@@ -556,6 +564,14 @@
         ALOGE("Could not create socket at %s: %s", addr.toString().c_str(), strerror(savedErrno));
         return -savedErrno;
     }
+
+    {
+        RpcMutexLockGuard _l(mLock);
+        if (mServerSocketModifier != nullptr) {
+            mServerSocketModifier(socket_fd);
+        }
+    }
+
     if (0 != TEMP_FAILURE_RETRY(bind(socket_fd.get(), addr.addr(), addr.addrSize()))) {
         int savedErrno = errno;
         ALOGE("Could not bind socket at %s: %s", addr.toString().c_str(), strerror(savedErrno));

libs/binder/include/binder/RpcServer.h

diff --git a/libs/binder/include/binder/RpcServer.h b/libs/binder/include/binder/RpcServer.h
index 1001b64..4816395 100644
--- a/libs/binder/include/binder/RpcServer.h
+++ b/libs/binder/include/binder/RpcServer.h
@@ -184,6 +184,13 @@
     void setConnectionFilter(std::function<bool(const void*, size_t)>&& filter);
 
     /**
+     * Set optional modifier of each newly created server socket.
+     *
+     * The only argument is a successfully created file descriptor, not bound to an address yet.
+     */
+    void setServerSocketModifier(std::function<void(base::borrowed_fd)>&& modifier);
+
+    /**
      * See RpcTransportCtx::getCertificate
      */
     std::vector<uint8_t> getCertificate(RpcCertificateFormat);
@@ -267,6 +274,7 @@
     wp<IBinder> mRootObjectWeak;
     std::function<sp<IBinder>(const void*, size_t)> mRootObjectFactory;
     std::function<bool(const void*, size_t)> mConnectionFilter;
+    std::function<void(base::borrowed_fd)> mServerSocketModifier;
     std::map<std::vector<uint8_t>, sp<RpcSession>> mSessions;
     std::unique_ptr<FdTrigger> mShutdownTrigger;
     RpcConditionVariable mShutdownCv;