Added two flags to emulation packages:

EMUL_BSD_ASYNCIO_PIPE notes that the emulated binaries expect the original
BSD pipe behavior for asynchronous I/O, which is to fire SIGIO on read() and
write(). OSes without this flag do not expect any SIGIO to be fired on
read() and write() for pipes, even when async I/O was requested. As far as
we know, the OSes that need EMUL_BSD_ASYNCIO_PIPE are NetBSD, OSF/1 and
Darwin.

EMUL_NO_SIGIO_ON_READ notes that the emulated binaries that requested
asynchrnous I/O expect the reader process to be notified by a SIGIO, but
not the writer process. OSes without this flag expect the reader and the
writer to be notified when some data has arrived or when some data have been
read. As far as we know, the OSes that need EMUL_NO_SIGIO_ON_READ are Linux
and SunOS.

sys/compat/linux/common/linux_exec.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: linux_exec.c,v 1.48 2001/03/24 11:13:04 jdolecek Exp $	*/
+/*	$NetBSD: linux_exec.c,v 1.49 2001/05/06 19:09:52 manu Exp $	*/
 
 /*-
  * Copyright (c) 1994, 1995, 1998, 2000 The NetBSD Foundation, Inc.
@@ -113,7 +113,7 @@ const struct emul emul_linux = {
 	"linux",
 	"/emul/linux",
 #ifndef __HAVE_MINIMAL_EMUL
-	0,
+	EMUL_NO_SIGIO_ON_READ,
 	(int*)native_to_linux_errno,
 	LINUX_SYS_syscall,
 	LINUX_SYS_MAXSYSCALL,

sys/compat/osf1/osf1_exec.c

@@ -1,4 +1,4 @@
-/* $NetBSD: osf1_exec.c,v 1.21 2000/12/13 03:16:39 mycroft Exp $ */
+/* $NetBSD: osf1_exec.c,v 1.22 2001/05/06 19:09:53 manu Exp $ */
 
 /*
  * Copyright (c) 1999 Christopher G. Demetriou.  All rights reserved.
@@ -52,7 +52,7 @@ const struct emul emul_osf1 = {
 	"osf1",
 	"/emul/osf1",
 #ifndef __HAVE_MINIMAL_EMUL
-	0,
+	EMUL_BSD_ASYNCIO_PIPE,
 	(int *)osf1_errno_rxlist,
 	OSF1_SYS_syscall,
 	OSF1_SYS_MAXSYSCALL,

sys/compat/sunos/sunos_exec.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: sunos_exec.c,v 1.29 2000/12/11 05:29:02 mycroft Exp $	*/
+/*	$NetBSD: sunos_exec.c,v 1.30 2001/05/06 19:09:53 manu Exp $	*/
 
 /*
  * Copyright (c) 1993 Theo de Raadt
@@ -52,7 +52,7 @@ void syscall __P((void));
 struct emul emul_sunos = {
 	"sunos",
 	"/emul/sunos",
-	0,
+	EMUL_NO_SIGIO_ON_READ,
 	NULL,
 	SUNOS_SYS_syscall,
 	SUNOS_SYS_MAXSYSCALL,

sys/compat/sunos32/sunos32_exec.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: sunos32_exec.c,v 1.2 2001/02/05 12:48:13 mrg Exp $	 */
+/*	$NetBSD: sunos32_exec.c,v 1.3 2001/05/06 19:09:54 manu Exp $	 */
 
 /*
  * Copyright (c) 2001 Matthew R. Green
@@ -50,7 +50,7 @@ void syscall __P((void));
 struct emul emul_sunos = {
 	"sunos32",
 	"/emul/sunos",
-	0,
+	EMUL_NO_SIGIO_ON_READ,
 	NULL,
 	SUNOS32_SYS_syscall,
 	SUNOS32_SYS_MAXSYSCALL,

sys/kern/kern_exec.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_exec.c,v 1.138 2001/02/26 20:43:25 lukem Exp $	*/
+/*	$NetBSD: kern_exec.c,v 1.139 2001/05/06 19:09:54 manu Exp $	*/
 
 /*-
  * Copyright (C) 1993, 1994, 1996 Christopher G. Demetriou
@@ -119,7 +119,7 @@ const struct emul emul_netbsd = {
 	"netbsd",
 	NULL,		/* emulation path */
 #ifndef __HAVE_MINIMAL_EMUL
-	EMUL_HAS_SYS___syscall,
+	EMUL_HAS_SYS___syscall | EMUL_BSD_ASYNCIO_PIPE,
 	NULL,
 	SYS_syscall,
 	SYS_MAXSYSCALL,

sys/sys/proc.h

@@ -1,4 +1,4 @@
-/*	$NetBSD: proc.h,v 1.126 2001/04/30 01:13:21 lukem Exp $	*/
+/*	$NetBSD: proc.h,v 1.127 2001/05/06 19:09:54 manu Exp $	*/
 
 /*-
  * Copyright (c) 1986, 1989, 1991, 1993
@@ -92,7 +92,7 @@ struct emul {
 	const char	*e_name;	/* Symbolic name */
 	const char	*e_path;	/* Extra emulation path (NULL if none)*/
 #ifndef __HAVE_MINIMAL_EMUL
-	int		e_flags;	/* Miscellaneous flags */
+	int		e_flags;	/* Miscellaneous flags, see above */
 					/* Syscall handling function */
 	const int	*e_errno;	/* Errno array */
 	int		e_nosys;	/* Offset of the nosys() syscall */
@@ -119,7 +119,12 @@ struct emul {
 #endif
 };
 
+/* 
+ * Emulation miscelaneous flags
+ */
 #define	EMUL_HAS_SYS___syscall	0x001	/* Has SYS___syscall */
+#define 	EMUL_BSD_ASYNCIO_PIPE	0x002 /* BSD style async I/O pipes */
+#define 	EMUL_NO_SIGIO_ON_READ	0x004 /* No SIGIO fired on read() calls*/
 
 /*
  * Description of a process.