From 661f76699fe78fa4ae7087e6da5c7b88c6c505a8 Mon Sep 17 00:00:00 2001
From: kleink <kleink@NetBSD.org>
Date: Sat, 25 Oct 2003 01:18:01 +0000
Subject: [PATCH] POSIX: when attempting to fdatasync(2) a file which is not
 open for writing, fail with EBADF.

---
 lib/libc/sys/fdatasync.2 | 6 +++---
 sys/kern/vfs_syscalls.c  | 8 ++++++--
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/lib/libc/sys/fdatasync.2 b/lib/libc/sys/fdatasync.2
index d8dd19536db6..5c3a33673397 100644
--- a/lib/libc/sys/fdatasync.2
+++ b/lib/libc/sys/fdatasync.2
@@ -1,4 +1,4 @@
-.\"	$NetBSD: fdatasync.2,v 1.13 2003/04/16 13:34:51 wiz Exp $
+.\"	$NetBSD: fdatasync.2,v 1.14 2003/10/25 01:18:01 kleink Exp $
 .\"
 .\" Copyright (c) 1998 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -34,7 +34,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd May 30, 1998
+.Dd October 25, 2003
 .Dt FDATASYNC 2
 .Os
 .Sh NAME
@@ -75,7 +75,7 @@ function will fail if:
 .It Bq Er EBADF
 The
 .Fa fd
-argument is not a valid file descriptor.
+argument is not a valid file descriptor open for writing.
 .It Bq Er EINVAL
 This implementation does not support synchronized I/O for this file.
 .It Bq Er ENOSYS
diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index 22316ec33859..eb9cb777b947 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: vfs_syscalls.c,v 1.198 2003/10/15 17:26:38 thorpej Exp $	*/
+/*	$NetBSD: vfs_syscalls.c,v 1.199 2003/10/25 01:18:01 kleink Exp $	*/
 
 /*
  * Copyright (c) 1989, 1993
@@ -37,7 +37,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_syscalls.c,v 1.198 2003/10/15 17:26:38 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_syscalls.c,v 1.199 2003/10/25 01:18:01 kleink Exp $");
 
 #include "opt_compat_netbsd.h"
 #include "opt_compat_43.h"
@@ -3025,6 +3025,10 @@ sys_fdatasync(l, v, retval)
 	/* getvnode() will use the descriptor for us */
 	if ((error = getvnode(p->p_fd, SCARG(uap, fd), &fp)) != 0)
 		return (error);
+	if ((fp->f_flag & FWRITE) == 0) {
+		FILE_UNUSE(fp, p);
+		return (EBADF);
+	}
 	vp = (struct vnode *)fp->f_data;
 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 	error = VOP_FSYNC(vp, fp->f_cred, FSYNC_WAIT|FSYNC_DATAONLY, 0, 0, p);