On Wed, 23 Jul 2003 jdolecek@netbsd.org wrote:

: The second problem is due to incorrect alignment of cmsgdata.

I've found that on i386, this isn't the reason for the EINVAL.  (Actually, I
think i386 NetBSD and Linux are using the same alignment for cmsgdata, but I
may be wrong.)

In any case, the following hack is currently in my tree, which addresses the
EINVAL issue.  I haven't yet tested it with *multiple* cmsg structures,
which would test out your alignment assertion above, but I know that it
makes passing a single fd work properly under Linux emulation.

I've considered going backwards-corkscrew on this and putting #ifdef
COMPAT_LINUX in uipc_usrreq.c, but that's still ugly.  The "real" fix would
be to convert Linux SOL_SOCKET (1) to NetBSD SOL_SOCKET (0xffff) on
sendmsg(), and convert it back on recvmsg() -- albeit one Hell of a lot of
stackgap munging.  The part on which I'm uneasy is linux_sys_recvmsg(),
which might need to pull out parts of the NetBSD sys_recvmsg() and work
directly with the kernel structures rather than doing a stackgap backflip.

Index: kern/uipc_usrreq.c
===================================================================
RCS file: /cvsroot/src/sys/kern/uipc_usrreq.c,v
retrieving revision 1.53
diff -u -r1.53 uipc_usrreq.c
--- kern/uipc_usrreq.c	2001/11/12 15:25:34	1.53
+++ kern/uipc_usrreq.c	2003/07/23 11:52:24
@@ -926,7 +926,7 @@
 	u_int neededspace;

 	/* Sanity check the control message header */
-	if (cm->cmsg_type != SCM_RIGHTS || cm->cmsg_level != SOL_SOCKET ||
+	if (cm->cmsg_type != SCM_RIGHTS || (cm->cmsg_level != SOL_SOCKET && cm->cmsg_level != 1) ||
 	    cm->cmsg_len != control->m_len)
 		return (EINVAL);

-- 
-- Todd Vierling <tv@pobox.com>