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

5 files changed, 31 insertions, 7 deletions

diff --git a/libs/binder/RpcServer.cpp b/libs/binder/RpcServer.cpp
index 66483edffb..a0c508be03 100644
--- a/libs/binder/RpcServer.cpp
+++ b/libs/binder/RpcServer.cpp
@@ -168,7 +168,7 @@ void RpcServer::join() {
     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 @@ status_t RpcServer::setupSocketServer(const RpcSocketAddress& addr) {
     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));
diff --git a/libs/binder/RpcSession.cpp b/libs/binder/RpcSession.cpp
index c756f2e8fb..73061b8948 100644
--- a/libs/binder/RpcSession.cpp
+++ b/libs/binder/RpcSession.cpp
@@ -39,6 +39,7 @@
 #include "RpcSocketAddress.h"
 #include "RpcState.h"
 #include "RpcWireFormat.h"
+#include "Utils.h"
 
 #ifdef __GLIBC__
 extern "C" pid_t gettid();
@@ -134,6 +135,10 @@ status_t RpcSession::setupPreconnectedClient(unique_fd fd, std::function<unique_
             fd = request();
             if (!fd.ok()) return BAD_VALUE;
         }
+        if (auto res = setNonBlocking(fd); !res.ok()) {
+            ALOGE("setupPreconnectedClient: %s", res.error().message().c_str());
+            return res.error().code() == 0 ? UNKNOWN_ERROR : -res.error().code();
+        }
         return initAndAddConnection(std::move(fd), sessionId, incoming);
     });
 }
@@ -470,8 +475,8 @@ status_t RpcSession::setupOneSocketConnection(const RpcSocketAddress& addr,
     for (size_t tries = 0; tries < 5; tries++) {
         if (tries > 0) usleep(10000);
 
-        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 at %s: %s", addr.toString().c_str(),
diff --git a/libs/binder/RpcTransportRaw.cpp b/libs/binder/RpcTransportRaw.cpp
index 995c54234f..46170f7f7a 100644
--- a/libs/binder/RpcTransportRaw.cpp
+++ b/libs/binder/RpcTransportRaw.cpp
@@ -50,7 +50,7 @@ public:
         return ret;
     }
     Result<size_t> peek(void *buf, size_t size) override {
-        ssize_t ret = TEMP_FAILURE_RETRY(::recv(mSocket.get(), buf, size, MSG_PEEK | MSG_DONTWAIT));
+        ssize_t ret = TEMP_FAILURE_RETRY(::recv(mSocket.get(), buf, size, MSG_PEEK));
         if (ret < 0) {
             return ErrnoError() << "recv(MSG_PEEK)";
         }
diff --git a/libs/binder/Utils.cpp b/libs/binder/Utils.cpp
index 90a4502ec5..d2a5be1102 100644
--- a/libs/binder/Utils.cpp
+++ b/libs/binder/Utils.cpp
@@ -18,10 +18,24 @@
 
 #include <string.h>
 
+using android::base::ErrnoError;
+using android::base::Result;
+
 namespace android {
 
 void zeroMemory(uint8_t* data, size_t size) {
     memset(data, 0, size);
 }
 
-}   // namespace android
+Result<void> setNonBlocking(android::base::borrowed_fd fd) {
+    int flags = TEMP_FAILURE_RETRY(fcntl(fd.get(), F_GETFL));
+    if (flags == -1) {
+        return ErrnoError() << "Could not get flags for fd";
+    }
+    if (int ret = TEMP_FAILURE_RETRY(fcntl(fd.get(), F_SETFL, flags | O_NONBLOCK)); ret == -1) {
+        return ErrnoError() << "Could not set non-blocking flag for fd";
+    }
+    return {};
+}
+
+} // namespace android
diff --git a/libs/binder/Utils.h b/libs/binder/Utils.h
index f94b158404..1e383da095 100644
--- a/libs/binder/Utils.h
+++ b/libs/binder/Utils.h
@@ -17,9 +17,14 @@
 #include <cstdint>
 #include <stddef.h>
 
+#include <android-base/result.h>
+#include <android-base/unique_fd.h>
+
 namespace android {
 
 // avoid optimizations
 void zeroMemory(uint8_t* data, size_t size);
 
+android::base::Result<void> setNonBlocking(android::base::borrowed_fd fd);
+
 }   // namespace android