From abf95952312f9cf679a3ebd0bb2f1758f1585f0f Mon Sep 17 00:00:00 2001
From: Ilya Zakharevich <ilya@math.berkeley.edu>
Date: Tue, 8 Jun 1999 00:47:58 -0400
Subject: [PATCH] Long-standing UDP sockets bug on OS/2

	Message-Id: <199906080847.EAA03810@monk.mps.ohio-state.edu>

p4raw-id: //depot/perl@3596
---
 pp_sys.c       |  4 ++++
 t/lib/io_udp.t | 20 +++++++++++++++-----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/pp_sys.c b/pp_sys.c
index 9600174..4e34a9e 100644
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -1462,6 +1462,10 @@ PP(pp_sysread)
 #else
 	bufsize = sizeof namebuf;
 #endif
+#ifdef OS2	/* At least Warp3+IAK: only the first byte of bufsize set */
+	if (bufsize >= 256)
+	    bufsize = 255;
+#endif
 	buffer = SvGROW(bufsv, length+1);
 	/* 'offset' means 'flags' here */
 	length = PerlSock_recvfrom(PerlIO_fileno(IoIFP(io)), buffer, length, offset,
diff --git a/t/lib/io_udp.t b/t/lib/io_udp.t
index 02112a2..8547024 100755
--- a/t/lib/io_udp.t
+++ b/t/lib/io_udp.t
@@ -19,9 +19,6 @@ BEGIN {
 	elsif ($Config{'extensions'} !~ /\bIO\b/) {
 	  $reason = 'IO was not built';
 	}
-	elsif ($^O eq 'os2') {
-	  $reason = "blocks on OS/2, not debugged yet";
-	}
 	elsif ($^O eq 'apollo') {
 	  $reason = "unknown *FIXME*";
 	}
@@ -36,6 +33,18 @@ BEGIN {
 sub compare_addr {
     my $a = shift;
     my $b = shift;
+    if (length($a) != length $b) {
+	my $min = (length($a) < length $b) ? length($a) : length $b;
+	if ($min and substr($a, 0, $min) eq substr($b, 0, $min)) {
+	    printf "# Apparently: %d bytes junk at the end of %s\n# %s\n",
+		abs(length($a) - length ($b)),
+		$_[length($a) < length ($b) ? 1 : 0],
+		"consider decreasing bufsize of recfrom.";
+	    substr($a, $min) = "";
+	    substr($b, $min) = "";
+	}
+	return 0;
+    }
     my @a = unpack_sockaddr_in($a);
     my @b = unpack_sockaddr_in($b);
     "$a[0]$a[1]" eq "$b[0]$b[1]";
@@ -65,7 +74,8 @@ print "ok 2\n";
 
 $udpa->send("ok 4\n",0,$udpb->sockname);
 
-print "not " unless compare_addr($udpa->peername,$udpb->sockname);
+print "not "
+  unless compare_addr($udpa->peername,$udpb->sockname, 'peername', 'sockname');
 print "ok 3\n";
 
 my $where = $udpb->recv($buf="",5);
@@ -73,7 +83,7 @@ print $buf;
 
 my @xtra = ();
 
-unless(compare_addr($where,$udpa->sockname)) {
+unless(compare_addr($where,$udpa->sockname, 'recv name', 'sockname')) {
     print "not ";
     @xtra = (0,$udpa->sockname);
 }
-- 
2.7.4