Add regression test for #9848.

Updates #9848

PiperOrigin-RevId: 595593495

test/syscalls/linux/bind_external.cc

@@ -12,6 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#ifdef __linux__
+#include <sys/epoll.h>
+#endif  // __linux__
 #include <errno.h>
 #include <stdlib.h>
 #include <sys/socket.h>
@@ -84,7 +87,63 @@ TEST_P(GoferStreamSeqpacketTest, BindListenAccept) {
   FileDescriptor accSock =
       ASSERT_NO_ERRNO_AND_VALUE(Accept(sock.get(), NULL, NULL));
 
-  // Other socket should be echo server.
+  // Other socket should be echo client.
+  constexpr int kBufferSize = 64;
+  char send_buffer[kBufferSize];
+  memset(send_buffer, 'a', sizeof(send_buffer));
+
+  ASSERT_THAT(WriteFd(accSock.get(), send_buffer, sizeof(send_buffer)),
+              SyscallSucceedsWithValue(sizeof(send_buffer)));
+
+  char recv_buffer[kBufferSize];
+  ASSERT_THAT(ReadFd(accSock.get(), recv_buffer, sizeof(recv_buffer)),
+              SyscallSucceedsWithValue(sizeof(recv_buffer)));
+  ASSERT_EQ(0, memcmp(send_buffer, recv_buffer, sizeof(send_buffer)));
+}
+
+// Create socket, register with epoll, bind to socket, Listen, wait for socket
+// to become ready using epoll and then Accept.
+TEST_P(GoferStreamSeqpacketTest, EpollBindListenWaitAccept) {
+  std::string env;
+  ProtocolSocket proto;
+  std::tie(env, proto) = GetParam();
+
+  char* val = getenv(env.c_str());
+  ASSERT_NE(val, nullptr);
+  std::string root(val);
+
+  FileDescriptor sock =
+      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_UNIX, proto.protocol, 0));
+
+  // Epoll on sockfd.
+  int efd;
+  ASSERT_THAT(efd = epoll_create(1), SyscallSucceeds());
+  FileDescriptor epollfd(efd);
+  struct epoll_event event = {};
+  event.events = EPOLLIN;
+  ASSERT_THAT(epoll_ctl(epollfd.get(), EPOLL_CTL_ADD, sock.get(), &event),
+              SyscallSucceeds());
+
+  std::string socket_path =
+      JoinPath(root, proto.name, "created-in-sandbox-epoll");
+
+  struct sockaddr_un addr = {};
+  addr.sun_family = AF_UNIX;
+  memcpy(addr.sun_path, socket_path.c_str(), socket_path.length());
+
+  ASSERT_THAT(
+      bind(sock.get(), reinterpret_cast<struct sockaddr*>(&addr), sizeof(addr)),
+      SyscallSucceeds());
+  ASSERT_THAT(listen(sock.get(), 1), SyscallSucceeds());
+
+  struct epoll_event results = {};
+  ASSERT_THAT(RetryEINTR(epoll_wait)(epollfd.get(), &results, 1, -1),
+              SyscallSucceeds());
+
+  FileDescriptor accSock =
+      ASSERT_NO_ERRNO_AND_VALUE(Accept(sock.get(), NULL, NULL));
+
+  // Other socket should be echo client.
   constexpr int kBufferSize = 64;
   char send_buffer[kBufferSize];
   memset(send_buffer, 'a', sizeof(send_buffer));

test/uds/uds.go

@@ -44,10 +44,8 @@ func doEcho(s *unet.Socket) error {
 	return nil
 }
 
-// createEchoSocket creates a socket that echoes back anything received.
-//
-// Only works for stream, seqpacket sockets.
-func createEchoSocket(path string, protocol int) (cleanup func(), err error) {
+// createEchoServer creates a socket that echoes back anything received.
+func createEchoServer(path string, protocol int) (cleanup func(), err error) {
 	fd, err := unix.Socket(unix.AF_UNIX, protocol, 0)
 	if err != nil {
 		return nil, fmt.Errorf("error creating echo(%d) socket: %v", protocol, err)
@@ -101,8 +99,8 @@ func createEchoSocket(path string, protocol int) (cleanup func(), err error) {
 	return cleanup, nil
 }
 
-// connectAndBecomeEcho connects to the given socket and turns into an echo server.
-func connectAndBecomeEcho(path string, protocol int) (cleanup func(), err error) {
+// createEchoClient connects to the given socket and turns into an echo client.
+func createEchoClient(path string, protocol int) (cleanup func(), err error) {
 	usePacket := protocol == unix.SOCK_SEQPACKET
 	go func() {
 		for {
@@ -115,7 +113,7 @@ func connectAndBecomeEcho(path string, protocol int) (cleanup func(), err error)
 			}
 			defer sock.Close()
 			for {
-				log.Infof("Connected to UDS at %q, running echo server", path)
+				log.Infof("Connected to UDS at %q, running echo client", path)
 				if err := doEcho(sock); err != nil {
 					return
 				}
@@ -337,7 +335,7 @@ func CreateBoundUDSTree(baseDir string) (string, func(), error) {
 			protocol: unix.SOCK_STREAM,
 			name:     "stream",
 			sockets: map[string]socketCreator{
-				"echo":         createEchoSocket,
+				"echo":         createEchoServer,
 				"nonlistening": createNonListeningSocket,
 			},
 		},
@@ -345,7 +343,7 @@ func CreateBoundUDSTree(baseDir string) (string, func(), error) {
 			protocol: unix.SOCK_SEQPACKET,
 			name:     "seqpacket",
 			sockets: map[string]socketCreator{
-				"echo":         createEchoSocket,
+				"echo":         createEchoServer,
 				"nonlistening": createNonListeningSocket,
 			},
 		},
@@ -360,24 +358,26 @@ func CreateBoundUDSTree(baseDir string) (string, func(), error) {
 }
 
 // CreateSocketConnectors creates goroutines that will attempt to connect to
-// sockets at the following locations, and turn into an echo server once
+// sockets at the following locations, and turn into an echo client once
 // connected:
-//   - /stream/created-in-sandbox
-//   - /seqpacket/created-in-sandbox
+//   - /stream/created-in-sandbox{-epoll}
+//   - /seqpacket/created-in-sandbox{-epoll}
 func CreateSocketConnectors(baseDir string) (string, func(), error) {
 	return createSocketTree(baseDir, []socketCreatorSpec{
 		{
 			protocol: unix.SOCK_STREAM,
 			name:     "stream",
 			sockets: map[string]socketCreator{
-				"created-in-sandbox": connectAndBecomeEcho,
+				"created-in-sandbox":       createEchoClient,
+				"created-in-sandbox-epoll": createEchoClient,
 			},
 		},
 		{
 			protocol: unix.SOCK_SEQPACKET,
 			name:     "seqpacket",
 			sockets: map[string]socketCreator{
-				"created-in-sandbox": connectAndBecomeEcho,
+				"created-in-sandbox":       createEchoClient,
+				"created-in-sandbox-epoll": createEchoClient,
 			},
 		},
 	})