libbinder: RPC flake mode

Add mode to make flakes more visible, for debugging.

Fixes: 190828148
Test: run w/ binderLibTest and the fuzzer for a bit (no tests
  fail - some tests can be made to fail by increasing the delay,
  but this is because some of the tests, namely OnewayStressTest,
  relies on all operations completing within a certain timeframe)
Change-Id: I3b38ff55ffc56410db585fa02e57ac0271da2b5d

1 files changed, 18 insertions, 0 deletions

diff --git a/libs/binder/RpcState.cpp b/libs/binder/RpcState.cpp
index 53eba5aea6..69ada56ed0 100644
--- a/libs/binder/RpcState.cpp
+++ b/libs/binder/RpcState.cpp
@@ -26,12 +26,28 @@
 #include "Debug.h"
 #include "RpcWireFormat.h"
 
+#include <random>
+
 #include <inttypes.h>
 
 namespace android {
 
 using base::ScopeGuard;
 
+#ifdef RPC_FLAKE_PRONE
+void rpcMaybeWaitToFlake() {
+    static std::random_device r;
+    static std::mutex m;
+
+    unsigned num;
+    {
+        std::lock_guard<std::mutex> lock(m);
+        num = r();
+    }
+    if (num % 10 == 0) usleep(num % 1000);
+}
+#endif
+
 RpcState::RpcState() {}
 RpcState::~RpcState() {}
 
@@ -226,6 +242,8 @@ status_t RpcState::rpcSend(const base::unique_fd& fd, const sp<RpcSession>& sess
                            const char* what, const void* data, size_t size) {
     LOG_RPC_DETAIL("Sending %s on fd %d: %s", what, fd.get(), hexString(data, size).c_str());
 
+    MAYBE_WAIT_IN_FLAKE_MODE;
+
     if (size > std::numeric_limits<ssize_t>::max()) {
         ALOGE("Cannot send %s at size %zu (too big)", what, size);
         (void)session->shutdownAndWait(false);