Indroduce fd_getfile_mode() and use it were fd_getfile() is directly

followed by a mode check.  This will simplify the ref/unref dance as
soon as fd_getfile() will increment fp's reference counter.

Idea from and ok guenther@, ok millert@

6 files changed, 34 insertions, 49 deletions

diff --git a/sys/compat/linux/linux_cdrom.c b/sys/compat/linux/linux_cdrom.c
index b1ca8e16af0..033a94bd8bb 100644
--- a/sys/compat/linux/linux_cdrom.c
+++ b/sys/compat/linux/linux_cdrom.c
@@ -1,5 +1,5 @@
 
-/*	$OpenBSD: linux_cdrom.c,v 1.11 2014/03/26 05:23:42 guenther Exp $	*/
+/*	$OpenBSD: linux_cdrom.c,v 1.12 2015/04/30 09:20:51 mpi Exp $	*/
 /*
  * Copyright 1997 Niels Provos <provos@physnet.uni-hamburg.de>
  * All rights reserved.
@@ -108,15 +108,10 @@ linux_ioctl_cdrom(p, v, retval)
 
 
 	fdp = p->p_fd;
-	if ((fp = fd_getfile(fdp, SCARG(uap, fd))) == NULL)
+	if ((fp = fd_getfile_mode(fdp, SCARG(uap, fd), FREAD|FWRITE)) == NULL)
 		return (EBADF);
 	FREF(fp);
 
-	if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
-		error = EBADF;
-		goto out;
-	}
-
 	com = SCARG(uap, com);
 	retval[0] = 0;
                 
diff --git a/sys/compat/linux/linux_termios.c b/sys/compat/linux/linux_termios.c
index 1baae7e2f6d..9b555947c6b 100644
--- a/sys/compat/linux/linux_termios.c
+++ b/sys/compat/linux/linux_termios.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: linux_termios.c,v 1.17 2014/03/26 05:23:42 guenther Exp $	*/
+/*	$OpenBSD: linux_termios.c,v 1.18 2015/04/30 09:20:51 mpi Exp $	*/
 /*	$NetBSD: linux_termios.c,v 1.3 1996/04/05 00:01:54 christos Exp $	*/
 
 /*
@@ -461,15 +461,10 @@ linux_ioctl_termios(p, v, retval)
 	int error = 0;
 
 	fdp = p->p_fd;
-	if ((fp = fd_getfile(fdp, SCARG(uap, fd))) == NULL)
+	if ((fp = fd_getfile_mode(fdp, SCARG(uap, fd), FREAD|FWRITE)) == NULL)
 		return (EBADF);
 	FREF(fp);
 
-	if ((fp->f_flag & (FREAD | FWRITE)) == 0) {
-		error = EBADF;
-		goto out;
-	}
-
 	com = SCARG(uap, com);
 	retval[0] = 0;
                 
diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c
index 2b55a32e7c1..2c8955c4d01 100644
--- a/sys/kern/kern_descrip.c
+++ b/sys/kern/kern_descrip.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_descrip.c,v 1.117 2015/03/14 03:38:50 jsg Exp $	*/
+/*	$OpenBSD: kern_descrip.c,v 1.118 2015/04/30 09:20:51 mpi Exp $	*/
 /*	$NetBSD: kern_descrip.c,v 1.42 1996/03/30 22:24:38 christos Exp $	*/
 
 /*
@@ -192,6 +192,21 @@ fd_getfile(struct filedesc *fdp, int fd)
 	return (fp);
 }
 
+struct file *
+fd_getfile_mode(struct filedesc *fdp, int fd, int mode)
+{
+	struct file *fp;
+
+	KASSERT(mode != 0);
+
+	fp = fd_getfile(fdp, fd);
+
+	if ((fp->f_flag & mode) == 0)
+		return (NULL);
+
+	return (fp);
+}
+
 /*
  * System calls on descriptors.
  */
diff --git a/sys/kern/sys_generic.c b/sys/kern/sys_generic.c
index 9c0f30be523..57b1813f080 100644
--- a/sys/kern/sys_generic.c
+++ b/sys/kern/sys_generic.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sys_generic.c,v 1.96 2015/02/12 22:27:04 millert Exp $	*/
+/*	$OpenBSD: sys_generic.c,v 1.97 2015/04/30 09:20:51 mpi Exp $	*/
 /*	$NetBSD: sys_generic.c,v 1.24 1996/03/29 00:25:32 cgd Exp $	*/
 
 /*
@@ -87,9 +87,7 @@ sys_read(struct proc *p, void *v, register_t *retval)
 	struct file *fp;
 	struct filedesc *fdp = p->p_fd;
 
-	if ((fp = fd_getfile(fdp, fd)) == NULL)
-		return (EBADF);
-	if ((fp->f_flag & FREAD) == 0)
+	if ((fp = fd_getfile_mode(fdp, fd, FREAD)) == NULL)
 		return (EBADF);
 
 	iov.iov_base = SCARG(uap, buf);
@@ -116,11 +114,8 @@ sys_readv(struct proc *p, void *v, register_t *retval)
 	struct file *fp;
 	struct filedesc *fdp = p->p_fd;
 
-	if ((fp = fd_getfile(fdp, fd)) == NULL)
-		return (EBADF);
-	if ((fp->f_flag & FREAD) == 0)
+	if ((fp = fd_getfile_mode(fdp, fd, FREAD)) == NULL)
 		return (EBADF);
-
 	FREF(fp);
 
 	/* dofilereadv() will FRELE the descriptor for us */
@@ -240,9 +235,7 @@ sys_write(struct proc *p, void *v, register_t *retval)
 	struct file *fp;
 	struct filedesc *fdp = p->p_fd;
 
-	if ((fp = fd_getfile(fdp, fd)) == NULL)
-		return (EBADF);
-	if ((fp->f_flag & FWRITE) == 0)
+	if ((fp = fd_getfile_mode(fdp, fd, FWRITE)) == NULL)
 		return (EBADF);
 
 	iov.iov_base = (void *)SCARG(uap, buf);
@@ -269,11 +262,8 @@ sys_writev(struct proc *p, void *v, register_t *retval)
 	struct file *fp;
 	struct filedesc *fdp = p->p_fd;
 
-	if ((fp = fd_getfile(fdp, fd)) == NULL)
+	if ((fp = fd_getfile_mode(fdp, fd, FWRITE)) == NULL)
 		return (EBADF);
-	if ((fp->f_flag & FWRITE) == 0)
-		return (EBADF);
-
 	FREF(fp);
 
 	/* dofilewritev() will FRELE the descriptor for us */
@@ -403,10 +393,7 @@ sys_ioctl(struct proc *p, void *v, register_t *retval)
 	long long stkbuf[STK_PARAMS / sizeof(long long)];
 
 	fdp = p->p_fd;
-	if ((fp = fd_getfile(fdp, SCARG(uap, fd))) == NULL)
-		return (EBADF);
-
-	if ((fp->f_flag & (FREAD | FWRITE)) == 0)
+	if ((fp = fd_getfile_mode(fdp, SCARG(uap, fd), FREAD|FWRITE)) == NULL)
 		return (EBADF);
 
 	switch (com = SCARG(uap, com)) {
diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index 7cac013b16b..81667eed88f 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vfs_syscalls.c,v 1.218 2015/04/17 04:43:20 guenther Exp $	*/
+/*	$OpenBSD: vfs_syscalls.c,v 1.219 2015/04/30 09:20:51 mpi Exp $	*/
 /*	$NetBSD: vfs_syscalls.c,v 1.71 1996/04/23 10:29:02 mycroft Exp $	*/
 
 /*
@@ -2824,9 +2824,7 @@ sys_pread(struct proc *p, void *v, register_t *retval)
 	off_t offset;
 	int fd = SCARG(uap, fd);
 
-	if ((fp = fd_getfile(fdp, fd)) == NULL)
-		return (EBADF);
-	if ((fp->f_flag & FREAD) == 0)
+	if ((fp = fd_getfile_mode(fdp, fd, FREAD)) == NULL)
 		return (EBADF);
 
 	vp = (struct vnode *)fp->f_data;
@@ -2867,9 +2865,7 @@ sys_preadv(struct proc *p, void *v, register_t *retval)
 	off_t offset;
 	int fd = SCARG(uap, fd);
 
-	if ((fp = fd_getfile(fdp, fd)) == NULL)
-		return (EBADF);
-	if ((fp->f_flag & FREAD) == 0)
+	if ((fp = fd_getfile_mode(fdp, fd, FREAD)) == NULL)
 		return (EBADF);
 
 	vp = (struct vnode *)fp->f_data;
@@ -2909,9 +2905,7 @@ sys_pwrite(struct proc *p, void *v, register_t *retval)
 	off_t offset;
 	int fd = SCARG(uap, fd);
 
-	if ((fp = fd_getfile(fdp, fd)) == NULL)
-		return (EBADF);
-	if ((fp->f_flag & FWRITE) == 0)
+	if ((fp = fd_getfile_mode(fdp, fd, FWRITE)) == NULL)
 		return (EBADF);
 
 	vp = (struct vnode *)fp->f_data;
@@ -2952,9 +2946,7 @@ sys_pwritev(struct proc *p, void *v, register_t *retval)
 	off_t offset;
 	int fd = SCARG(uap, fd);
 
-	if ((fp = fd_getfile(fdp, fd)) == NULL)
-		return (EBADF);
-	if ((fp->f_flag & FWRITE) == 0)
+	if ((fp = fd_getfile_mode(fdp, fd, FWRITE)) == NULL)
 		return (EBADF);
 
 	vp = (struct vnode *)fp->f_data;
diff --git a/sys/sys/filedesc.h b/sys/sys/filedesc.h
index b383a38351e..2016441326b 100644
--- a/sys/sys/filedesc.h
+++ b/sys/sys/filedesc.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: filedesc.h,v 1.28 2014/05/15 03:52:25 guenther Exp $	*/
+/*	$OpenBSD: filedesc.h,v 1.29 2015/04/30 09:20:51 mpi Exp $	*/
 /*	$NetBSD: filedesc.h,v 1.14 1996/04/09 20:55:28 cgd Exp $	*/
 
 /*
@@ -132,7 +132,8 @@ void	fdfree(struct proc *p);
 int	fdrelease(struct proc *p, int);
 void	fdremove(struct filedesc *, int);
 void	fdcloseexec(struct proc *);
-struct file *fd_getfile(struct filedesc *, int fd);
+struct file *fd_getfile(struct filedesc *, int);
+struct file *fd_getfile_mode(struct filedesc *, int, int);
 
 int	closef(struct file *, struct proc *);
 int	getsock(struct filedesc *, int, struct file **);