win32_recvfrom() compatibility fix

p4raw-id: //depot/perl@2254

1 files changed, 7 insertions, 0 deletions

diff --git a/win32/win32sck.c b/win32/win32sck.c
index 52dc128f9a..2713605840 100644
--- a/win32/win32sck.c
+++ b/win32/win32sck.c
@@ -287,8 +287,15 @@ int
 win32_recvfrom(SOCKET s, char *buf, int len, int flags, struct sockaddr *from, int *fromlen)
 {
     int r;
+    int frombufsize = *fromlen;
 
     SOCKET_TEST_ERROR(r = recvfrom(TO_SOCKET(s), buf, len, flags, from, fromlen));
+    /* Winsock's recvfrom() only returns a valid 'from' when the socket
+     * is connectionless.  Perl expects a valid 'from' for all types
+     * of sockets, so go the extra mile.
+     */
+    if (r != SOCKET_ERROR && frombufsize == *fromlen)
+	(void)win32_getpeername(s, from, fromlen);
     return r;
 }