issue: 4680622 Fix pktinfo test EINTR failures

The pktinfo.check_recvmsg_returns_expected_pktinfo test was failing
sporadically with errno=4 (EINTR) when SIGCHLD from the child process
exit interrupted the recvmsg() syscall before it could read the
buffered packet data.

Add standard EINTR retry loop to handle signal interruption during
recvmsg(), allowing the syscall to complete successfully even when
interrupted by signals.

Fixes sporadic CI failures:
  Expected: (recvmsg(fd, &msg, 0)) > (0), actual: -1 vs 0
  Failed to receive the msg

Signed-off-by: Tomer Cabouly <[email protected]>

Author: tomerdbz

tests/gtest/udp/udp_bind.cc

@@ -529,7 +529,11 @@ TEST_F(pktinfo, check_recvmsg_returns_expected_pktinfo)
                 &client_addr.addr, sizeof(client_addr.addr), &vec, 1U, cbuf, sizeof(cbuf), 0
             };
 
-            ASSERT_GT(recvmsg(fd, &msg, 0), 0) << "Failed to receive the msg";
+            ssize_t ret;
+            do {
+                ret = recvmsg(fd, &msg, 0);
+            } while (ret < 0 && errno == EINTR);
+            ASSERT_GT(ret, 0) << "Failed to receive the msg, errno=" << errno;
 
             struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);