[libc-commits] [libc] [libc] Add the MSG_ flags (PR #194375)

[Pavel Labath via libc-commits]

================
@@ -46,6 +46,46 @@ TEST_F(LlvmLibcSendRecvTest, SucceedsWithSocketPair) {
   ASSERT_THAT(LIBC_NAMESPACE::close(sockpair[1]), Succeeds(0));
 }
 
+TEST_F(LlvmLibcSendRecvTest, MsgFlagsTest) {
+  int sockpair[2] = {0, 0};
+
+  ASSERT_THAT(LIBC_NAMESPACE::socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sockpair),
+              Succeeds(0));
+
+  char buffer[256];
+
+  // MSG_DONTWAIT on an empty socket returns EAGAIN
+  ASSERT_THAT(
+      LIBC_NAMESPACE::recv(sockpair[1], buffer, sizeof(buffer), MSG_DONTWAIT),
+      Fails<ssize_t>(EAGAIN));
+
+  const char TEST_MESSAGE[] = "this is a long message";
+  const size_t MESSAGE_LEN = sizeof(TEST_MESSAGE);
+
+  ASSERT_THAT(LIBC_NAMESPACE::send(sockpair[0], TEST_MESSAGE, MESSAGE_LEN, 0),
+              Succeeds(static_cast<ssize_t>(MESSAGE_LEN)));
+
+  // MSG_PEEK does not remove the message from the socket
+  ASSERT_THAT(
+      LIBC_NAMESPACE::recv(sockpair[1], buffer, sizeof(buffer), MSG_PEEK),
+      Succeeds(static_cast<ssize_t>(MESSAGE_LEN)));
+  ASSERT_STREQ(buffer, TEST_MESSAGE);
+  LIBC_NAMESPACE::memset(buffer, 0, sizeof(buffer));
----------------
labath wrote:

Using a new buffer.

https://github.com/llvm/llvm-project/pull/194375