commit ffa3aaac5513bc2ef6c7d3f88db9976f86275f88
author Andrei Homescu <ahomescu@google.com> Thu Apr 07 05:06:33 2022 +0000
committer Andrei Homescu <ahomescu@google.com> Fri Jul 01 05:50:42 2022 +0000
tree 5f3b4577b71bb529d7954c28f9d0390a558afc63
parent 992a405fd8d4025f5c5e7423530f398d459fff6b

libbinder: add build option for single-threaded RPC

Trusty does not support threading. This adds a build option
to disable mutexes and other threading code from RpcState,
RpcSession, and RpcServer.

Bug: 224644083
Test: build Trusty
Change-Id: Iaa78caca1ddee45be7c2def2755598decc0d4d15

libs/binder/RpcState.cpp

diff --git a/libs/binder/RpcState.cpp b/libs/binder/RpcState.cpp
index 8f104bc..01311b5 100644
--- a/libs/binder/RpcState.cpp
+++ b/libs/binder/RpcState.cpp
@@ -45,7 +45,7 @@
     [[clang::no_destroy]] static std::mutex m;
     unsigned num;
     {
-        std::lock_guard<std::mutex> lock(m);
+        RpcMutexLockGuard lock(m);
         num = r();
     }
     if (num % 10 == 0) usleep(num % 1000);
@@ -89,7 +89,7 @@
         return INVALID_OPERATION;
     }
 
-    std::lock_guard<std::mutex> _l(mNodeMutex);
+    RpcMutexLockGuard _l(mNodeMutex);
     if (mTerminated) return DEAD_OBJECT;
 
     // TODO(b/182939933): maybe move address out of BpBinder, and keep binder->address map
@@ -165,7 +165,7 @@
         return BAD_VALUE;
     }
 
-    std::lock_guard<std::mutex> _l(mNodeMutex);
+    RpcMutexLockGuard _l(mNodeMutex);
     if (mTerminated) return DEAD_OBJECT;
 
     if (auto it = mNodeForAddress.find(address); it != mNodeForAddress.end()) {
@@ -200,7 +200,7 @@
     // extra reference counting packets now.
     if (binder->remoteBinder()) return OK;
 
-    std::unique_lock<std::mutex> _l(mNodeMutex);
+    RpcMutexUniqueLock _l(mNodeMutex);
     if (mTerminated) return DEAD_OBJECT;
 
     auto it = mNodeForAddress.find(address);
@@ -228,17 +228,17 @@
 }
 
 size_t RpcState::countBinders() {
-    std::lock_guard<std::mutex> _l(mNodeMutex);
+    RpcMutexLockGuard _l(mNodeMutex);
     return mNodeForAddress.size();
 }
 
 void RpcState::dump() {
-    std::lock_guard<std::mutex> _l(mNodeMutex);
+    RpcMutexLockGuard _l(mNodeMutex);
     dumpLocked();
 }
 
 void RpcState::clear() {
-    std::unique_lock<std::mutex> _l(mNodeMutex);
+    RpcMutexUniqueLock _l(mNodeMutex);
 
     if (mTerminated) {
         LOG_ALWAYS_FATAL_IF(!mNodeForAddress.empty(),
@@ -488,7 +488,7 @@
     uint64_t asyncNumber = 0;
 
     if (address != 0) {
-        std::unique_lock<std::mutex> _l(mNodeMutex);
+        RpcMutexUniqueLock _l(mNodeMutex);
         if (mTerminated) return DEAD_OBJECT; // avoid fatal only, otherwise races
         auto it = mNodeForAddress.find(address);
         LOG_ALWAYS_FATAL_IF(it == mNodeForAddress.end(),
@@ -671,7 +671,7 @@
     };
 
     {
-        std::lock_guard<std::mutex> _l(mNodeMutex);
+        RpcMutexLockGuard _l(mNodeMutex);
         if (mTerminated) return DEAD_OBJECT; // avoid fatal only, otherwise races
         auto it = mNodeForAddress.find(addr);
         LOG_ALWAYS_FATAL_IF(it == mNodeForAddress.end(),
@@ -840,7 +840,7 @@
             (void)session->shutdownAndWait(false);
             replyStatus = BAD_VALUE;
         } else if (oneway) {
-            std::unique_lock<std::mutex> _l(mNodeMutex);
+            RpcMutexUniqueLock _l(mNodeMutex);
             auto it = mNodeForAddress.find(addr);
             if (it->second.binder.promote() != target) {
                 ALOGE("Binder became invalid during transaction. Bad client? %" PRIu64, addr);
@@ -981,7 +981,7 @@
         // downside: asynchronous transactions may drown out synchronous
         // transactions.
         {
-            std::unique_lock<std::mutex> _l(mNodeMutex);
+            RpcMutexUniqueLock _l(mNodeMutex);
             auto it = mNodeForAddress.find(addr);
             // last refcount dropped after this transaction happened
             if (it == mNodeForAddress.end()) return OK;
@@ -1089,7 +1089,7 @@
         return status;
 
     uint64_t addr = RpcWireAddress::toRaw(body.address);
-    std::unique_lock<std::mutex> _l(mNodeMutex);
+    RpcMutexUniqueLock _l(mNodeMutex);
     auto it = mNodeForAddress.find(addr);
     if (it == mNodeForAddress.end()) {
         ALOGE("Unknown binder address %" PRIu64 " for dec strong.", addr);