commit b675ffe41b574bd7a13ebbc8682cf147508b5c21
author Yifan Hong <elsk@google.com> Thu Aug 05 16:37:17 2021 -0700
committer Yifan Hong <elsk@google.com> Fri Aug 06 12:09:40 2021 -0700
tree 563138d017c6ccd0b587876c2c8bc66133b6bce1
parent 8c950421dbe8d9c2cea5e293b925b01d6f8c52da

binder: RPC uses non-blocking sockets.

With TLS, even though poll() may have returned for an FD,
there may not be a complete packet available, so I/O operations
within libssl may block and not interruptible by the shutdown
trigger.

Hence, always use non-blocking sockets.

Test: binderRpcTest
Bug: 195683291
Change-Id: I372e8c3bf010c672b1c4b9f7cb5b789ca20c9480

libs/binder/RpcServer.cpp

diff --git a/libs/binder/RpcServer.cpp b/libs/binder/RpcServer.cpp
index 66483ed..a0c508b 100644
--- a/libs/binder/RpcServer.cpp
+++ b/libs/binder/RpcServer.cpp
@@ -168,7 +168,7 @@
     status_t status;
     while ((status = mShutdownTrigger->triggerablePoll(mServer, POLLIN)) == OK) {
         unique_fd clientFd(TEMP_FAILURE_RETRY(
-                accept4(mServer.get(), nullptr, nullptr /*length*/, SOCK_CLOEXEC)));
+                accept4(mServer.get(), nullptr, nullptr /*length*/, SOCK_CLOEXEC | SOCK_NONBLOCK)));
 
         if (clientFd < 0) {
             ALOGE("Could not accept4 socket: %s", strerror(errno));
@@ -388,8 +388,8 @@
     LOG_RPC_DETAIL("Setting up socket server %s", addr.toString().c_str());
     LOG_ALWAYS_FATAL_IF(hasServer(), "Each RpcServer can only have one server.");
 
-    unique_fd serverFd(
-            TEMP_FAILURE_RETRY(socket(addr.addr()->sa_family, SOCK_STREAM | SOCK_CLOEXEC, 0)));
+    unique_fd serverFd(TEMP_FAILURE_RETRY(
+            socket(addr.addr()->sa_family, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0)));
     if (serverFd == -1) {
         int savedErrno = errno;
         ALOGE("Could not create socket: %s", strerror(savedErrno));