Add a clonable devices implementation. Hacked along with thib@, input

from krw@ and toby@, subliminal prodding from dlg@, okay deraadt@.

3 files changed, 117 insertions, 2 deletions

diff --git a/sys/miscfs/specfs/spec_subr.c b/sys/miscfs/specfs/spec_subr.c
new file mode 100644
index 00000000000..8cc38e4829f
--- /dev/null
+++ b/sys/miscfs/specfs/spec_subr.c
@@ -0,0 +1,95 @@
+/*	$OpenBSD: spec_subr.c,v 1.1 2006/06/02 20:25:09 pedro Exp $	*/
+
+/*
+ * Copyright (c) 2006 Pedro Martelletto <pedro@openbsd.org>
+ * Copyright (c) 2006 Thordur Bjornsson <thib@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+#include <sys/vnode.h>
+#include <sys/malloc.h>
+#include <sys/conf.h>
+#include <sys/stat.h>
+
+#include <miscfs/specfs/specdev.h>
+
+int
+spec_open_clone(struct vop_open_args *ap)
+{
+	struct vnode *cvp, *vp = ap->a_vp;
+	struct cloneinfo *cip;
+	int error, i;
+
+	for (i = 1; i < sizeof(vp->v_specbitmap) * NBBY; i++)
+		if (isclr(vp->v_specbitmap, i)) {
+			setbit(vp->v_specbitmap, i);
+			break;
+		}
+
+	if (i == sizeof(vp->v_specbitmap) * NBBY)
+		return (EBUSY);
+
+	printf("spec_open_clone(): cloning device (%d, %d) for pid %u\n",
+	    major(vp->v_rdev), minor(vp->v_rdev), curproc->p_pid);
+
+	error = cdevvp(makedev(major(vp->v_rdev), i), &cvp);
+	if (error)
+		return (error); /* out of vnodes */
+
+	VOP_UNLOCK(vp, 0, ap->a_p);
+
+	error = cdevsw[major(vp->v_rdev)].d_open(cvp->v_rdev, ap->a_mode,
+	    S_IFCHR, ap->a_p);
+
+	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, ap->a_p);
+
+	if (error) {
+		 clrbit(vp->v_specbitmap, i);
+		 return (error);
+	}
+
+	cip = malloc(sizeof(struct cloneinfo), M_TEMP, M_WAITOK);
+	cip->ci_data = vp->v_data;
+	cip->ci_vp = cvp;
+
+	cvp->v_specparent = vp;
+	vp->v_flag |= VCLONED;
+	vp->v_data = cip;
+
+	printf("spec_open_clone(): new minor for cloned device is %d\n",
+	    minor(cvp->v_rdev));
+
+	return (0); /* device cloned */
+}
+
+int
+spec_close_clone(struct vop_close_args *ap)
+{
+	struct vnode *pvp, *vp = ap->a_vp;
+	int error;
+
+	error = cdevsw[major(vp->v_rdev)].d_close(vp->v_rdev, ap->a_fflag,
+	    S_IFCHR, ap->a_p);
+	if (error)
+		return (error);
+
+	pvp = vp->v_specparent; /* get parent device */
+	clrbit(pvp->v_specbitmap, minor(vp->v_rdev));
+
+	printf("spec_close_clone(): freeing minor %d of dev %d for"
+	    " pid %u\n", minor(vp->v_rdev), major(vp->v_rdev), curproc->p_pid);
+
+	return (0);
+}
diff --git a/sys/miscfs/specfs/spec_vnops.c b/sys/miscfs/specfs/spec_vnops.c
index 1f3fe5db55f..6b5558c733f 100644
--- a/sys/miscfs/specfs/spec_vnops.c
+++ b/sys/miscfs/specfs/spec_vnops.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: spec_vnops.c,v 1.33 2006/03/05 21:48:56 miod Exp $	*/
+/*	$OpenBSD: spec_vnops.c,v 1.34 2006/06/02 20:25:09 pedro Exp $	*/
 /*	$NetBSD: spec_vnops.c,v 1.29 1996/04/22 01:42:38 christos Exp $	*/
 
 /*
@@ -191,6 +191,8 @@ spec_open(v)
 		}
 		if (cdevsw[maj].d_type == D_TTY)
 			vp->v_flag |= VISTTY;
+		if (cdevsw[maj].d_flags & D_CLONE)
+			return (spec_open_clone(ap));
 		VOP_UNLOCK(vp, 0, p);
 		error = (*cdevsw[maj].d_open)(dev, ap->a_mode, S_IFCHR, ap->a_p);
 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
@@ -624,6 +626,8 @@ spec_close(v)
 		 */
 		if (vcount(vp) > 1 && (vp->v_flag & VXLOCK) == 0)
 			return (0);
+		if (cdevsw[major(dev)].d_flags & D_CLONE)
+			return (spec_close_clone(ap));
 		devclose = cdevsw[major(dev)].d_close;
 		mode = S_IFCHR;
 		break;
diff --git a/sys/miscfs/specfs/specdev.h b/sys/miscfs/specfs/specdev.h
index bb95a71025d..8fc18c628b5 100644
--- a/sys/miscfs/specfs/specdev.h
+++ b/sys/miscfs/specfs/specdev.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: specdev.h,v 1.17 2003/09/23 16:51:13 millert Exp $	*/
+/*	$OpenBSD: specdev.h,v 1.18 2006/06/02 20:25:09 pedro Exp $	*/
 /*	$NetBSD: specdev.h,v 1.12 1996/02/13 13:13:01 mycroft Exp $	*/
 
 /*
@@ -44,7 +44,17 @@ struct specinfo {
 	dev_t	si_rdev;
 	struct	lockf *si_lockf;
 	daddr_t si_lastr;
+	union {
+		struct vnode *ci_parent; /* pointer back to parent device */
+		u_int8_t ci_bitmap[8]; /* bitmap of devices cloned off us */
+	} si_ci;
 };
+
+struct cloneinfo {
+	struct vnode *ci_vp; /* cloned vnode */
+	void *ci_data; /* original vnode's v_data */
+};
+
 /*
  * Exported shorthand
  */
@@ -53,6 +63,8 @@ struct specinfo {
 #define v_specnext v_specinfo->si_specnext
 #define v_specmountpoint v_specinfo->si_mountpoint
 #define v_speclockf v_specinfo->si_lockf
+#define v_specparent v_specinfo->si_ci.ci_parent
+#define v_specbitmap v_specinfo->si_ci.ci_bitmap
 
 /*
  * Special device management
@@ -119,3 +131,7 @@ int	spec_advlock(void *);
 #define spec_revoke     vop_generic_revoke
 
 int	spec_vnoperate(void *);
+
+/* spec_subr.c */
+int	spec_open_clone(struct vop_open_args *);
+int	spec_close_clone(struct vop_close_args *);