Added new test case using sendto and recvfrom functions

Added to two_socket_communication test in omrsockTest.cpp

- Added test case that involves datagram communication.
- Set timeout for sendto and recvfrom to be 2 seconds.
- However, because of the inconsistency in receiving the message
  for datagram communication, the message is sent 50 times and
  received using recvfrom for up to 50 times until it receives
  the same number of bytes as it sent.

Issue: eclipse-omr#5128

Signed-off-by: Haley Cao <haleycao88@hotmail.com>

fvtest/porttest/omrsockTest.cpp

@@ -589,6 +589,44 @@ TEST(PortSockTest, two_socket_datagram_communication)
 	/* Connect is optional for datagram clients */
 	EXPECT_EQ(connect_client_to_server(OMRPORTLIB, (char *)"localhost", NULL, OMRSOCK_AF_INET, OMRSOCK_DGRAM, &clientSocket, &clientSockAddr, &serverSockAddr), 0);
 
+/* Datagram Sendto and Recvfrom test. Sendto and Recvfrom are called multiple tests to ensure it has been
+ *	sent and received.
+ */
+	OMRTimeval timeSend;
+	OMRTimeval timeRecv;
+	EXPECT_EQ(OMRPORTLIB->sock_timeval_init(OMRPORTLIB, &timeSend, 2, 0), 0);
+	EXPECT_EQ(OMRPORTLIB->sock_timeval_init(OMRPORTLIB, &timeRecv, 5, 0), 0);
+	EXPECT_EQ(OMRPORTLIB->sock_setsockopt_timeval(OMRPORTLIB, clientSocket, OMRSOCK_SOL_SOCKET, OMRSOCK_SO_RCVTIMEO, &timeRecv), 0);
+	EXPECT_EQ(OMRPORTLIB->sock_setsockopt_timeval(OMRPORTLIB, clientSocket, OMRSOCK_SOL_SOCKET, OMRSOCK_SO_SNDTIMEO, &timeSend), 0);
+	EXPECT_EQ(OMRPORTLIB->sock_setsockopt_timeval(OMRPORTLIB, serverSocket, OMRSOCK_SOL_SOCKET, OMRSOCK_SO_RCVTIMEO, &timeRecv), 0);
+	EXPECT_EQ(OMRPORTLIB->sock_setsockopt_timeval(OMRPORTLIB, serverSocket, OMRSOCK_SOL_SOCKET, OMRSOCK_SO_SNDTIMEO, &timeSend), 0);
+
+	/* Send 50 times. This should be enough for the message to be sent. */
+	char msgDgram[100] = "This is an omrsock test for datagram communications.";
+	int32_t	bytesLeft = strlen(msgDgram) + 1;
+
+	for (int32_t i = 0; i < 200; i++) {
+		OMRPORTLIB->sock_sendto(OMRPORTLIB, clientSocket, (uint8_t *)msgDgram, bytesLeft, 0, &serverSockAddr);
+	}
+
+	/* Receive */
+	char bufDgram[100] = "";
+	int32_t bytesRecv = 0;
+
+	for (int32_t i = 0; i < 200; i++) {
+		bytesRecv = OMRPORTLIB->sock_recvfrom(OMRPORTLIB, serverSocket, (uint8_t *)bufDgram, bytesLeft, 0, &clientSockAddr);
+		printf("iteration %d: bytesRecv is %d \n", i, bytesRecv);
+		if (bytesRecv == bytesLeft) {
+			printf("break encountered at iter %d \n", i);
+			break;
+		}
+	}
+
+	printf("sent: %s \n", msgDgram);
+	printf("received: %s \n", bufDgram);
+
+	EXPECT_EQ(strcmp(msgDgram, bufDgram), 0);
+
 	EXPECT_EQ(OMRPORTLIB->sock_close(OMRPORTLIB, &clientSocket), 0);
 	EXPECT_EQ(OMRPORTLIB->sock_close(OMRPORTLIB, &serverSocket), 0);
 }

port/unix/omrsock.c

@@ -698,7 +698,7 @@ omrsock_recvfrom(struct OMRPortLibrary *portLibrary, omrsock_socket_t sock, uint
 	}
 	if (-1 == bytesRecv) {
 		portLibrary->error_set_last_error(portLibrary, errno, OMRPORT_ERROR_SOCK_RECVFROM_FAILED);
-		return OMRPORT_ERROR_SOCK_RECVFROM_FAILED;
+		return errno;
 	}
 
 	return bytesRecv;