Add Capsicum capability mode support; svn add of capability.h was missed

in a previous commit.  Whoops!

Reported by:	jhb
Reviewed by:	anderson
Discussed with:	benl, kris, pjd
Sponsored by:	Google, Inc.
Obtained from:	Capsicum Project
MFC after:	3 months

sys/sys/capability.h

@@ -0,0 +1,71 @@
+/*-
+ * Copyright (c) 2008-2010 Robert N. M. Watson
+ * All rights reserved.
+ *
+ * This software was developed at the University of Cambridge Computer
+ * Laboratory with support from a grant from Google, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * Definitions for FreeBSD capabilities facility.
+ */
+#ifndef _SYS_CAPABILITY_H_
+#define	_SYS_CAPABILITY_H_
+
+#include <sys/cdefs.h>
+#include <sys/types.h>
+
+#ifdef _KERNEL
+
+#define IN_CAPABILITY_MODE(td) (td->td_ucred->cr_flags & CRED_FLAG_CAPMODE)
+
+#else /* !_KERNEL */
+
+__BEGIN_DECLS
+
+/*
+ * cap_enter(): Cause the process to enter capability mode, which will
+ * prevent it from directly accessing global namespaces.  System calls will
+ * be limited to process-local, process-inherited, or file descriptor
+ * operations.  If already in capability mode, a no-op.
+ *
+ * Currently, process-inherited operations are not properly handled -- in
+ * particular, we're interested in things like waitpid(2), kill(2), etc,
+ * being properly constrained.  One possible solution is to introduce process
+ * descriptors.
+ */
+int	cap_enter(void);
+
+/*
+ * cap_getmode(): Are we in capability mode?
+ */
+int	cap_getmode(u_int* modep);
+
+__END_DECLS
+
+#endif /* !_KERNEL */
+
+#endif /* !_SYS_CAPABILITY_H_ */