Add missing documention:

 - fork1() flags: FORK_SIGHAND, FORK_PTRACE, and FORK_THREAD
 - RTHREADS kernel option
 - rfork() RFTHREAD flag (with a BUGS entry that it's not usable from C)

ok tedu@

3 files changed, 48 insertions, 6 deletions

diff --git a/lib/libc/sys/rfork.2 b/lib/libc/sys/rfork.2
index 5a874b4b33b..0d9a6ccf7a3 100644
--- a/lib/libc/sys/rfork.2
+++ b/lib/libc/sys/rfork.2
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: rfork.2,v 1.23 2007/05/31 19:19:33 jmc Exp $
+.\"	$OpenBSD: rfork.2,v 1.24 2010/04/03 01:49:44 guenther Exp $
 .\"
 .\" Copyright (c) 2003 Jason McIntyre <jmc@openbsd.org>
 .\"
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: May 31 2007 $
+.Dd $Mdocdate: April 3 2010 $
 .Dt RFORK 2
 .Os
 .Sh NAME
@@ -108,6 +108,14 @@ Zero the child's file descriptor table
 .Pq i.e. start with a blank file descriptor table .
 May not be used in conjunction with
 .Dv RFFDG .
+.It Dv RFTHREAD
+Create a kernel thread in the current process instead of a separate
+process.
+Must be combined with
+.Dv RFMEM .
+Automatically enables
+.Dv RFNOWAIT .
+The kernel option RTHREADS must be enabled for this to succeed.
 .El
 .Pp
 .Xr fork 2
@@ -157,6 +165,11 @@ as
 .Dv CHILD_MAX ,
 which is currently defined as 80 in
 .Aq Pa sys/syslimits.h .
+.It Bq Er ENOTSUP
+The
+.Dv RFTHREAD
+flag was set but the kernel was not compiled with the RTHREADS
+kernel option.
 .El
 .Sh SEE ALSO
 .Xr _exit 2 ,
@@ -168,3 +181,6 @@ which is currently defined as 80 in
 The
 .Fn rfork
 function first appeared in Plan 9.
+.Sh BUGS
+.Dv RFTHREAD
+cannot be used from C, as the two threads would return on the same stack.
diff --git a/share/man/man4/options.4 b/share/man/man4/options.4
index 25f2573cb24..b6ba58cae45 100644
--- a/share/man/man4/options.4
+++ b/share/man/man4/options.4
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: options.4,v 1.194 2009/10/22 09:22:46 sobrado Exp $
+.\"	$OpenBSD: options.4,v 1.195 2010/04/03 01:49:44 guenther Exp $
 .\"	$NetBSD: options.4,v 1.21 1997/06/25 03:13:00 thorpej Exp $
 .\"
 .\" Copyright (c) 1998 Theo de Raadt
@@ -34,7 +34,7 @@
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
 .\"
-.Dd $Mdocdate: October 22 2009 $
+.Dd $Mdocdate: April 3 2010 $
 .Dt OPTIONS 4
 .Os
 .Sh NAME
@@ -562,6 +562,12 @@ See
 and
 .Xr raidctl 8
 for details.
+.It Cd option RTHREADS
+Enable kernel support for kernel-level threads via the
+.Dv RFTHREAD
+flag to
+.Xr rfork 2 .
+Currently incomplete.
 .It Cd option USER_LDT
 Enable userland manipulation of per-process
 Local Descriptor Table (LDT) entries;
diff --git a/share/man/man9/fork1.9 b/share/man/man9/fork1.9
index 8d927e698e4..c81efc89fa0 100644
--- a/share/man/man9/fork1.9
+++ b/share/man/man9/fork1.9
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: fork1.9,v 1.12 2009/07/28 12:27:03 jmc Exp $
+.\"	$OpenBSD: fork1.9,v 1.13 2010/04/03 01:49:44 guenther Exp $
 .\"	$NetBSD: fork1.9,v 1.3 1999/03/16 00:40:47 garbled Exp $
 .\"
 .\" Copyright (c) 1998 The NetBSD Foundation, Inc.
@@ -29,7 +29,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: July 28 2009 $
+.Dd $Mdocdate: April 3 2010 $
 .Dt FORK1 9
 .Os
 .Sh NAME
@@ -105,6 +105,26 @@ See
 The child will share the parent's address space.
 The default behavior is
 that the child gets a copy-on-write copy of the address space.
+.It Dv FORK_SIGHAND
+The child will share the parent's signal actions, including the handler,
+mask, and flags, with sigactsshare().
+The default behavior is to copy the signal actions from the parent with
+sigactsinit().
+.Dv FORK_SHAREVM
+must also be set.
+.It Dv FORK_PTRACE
+The child will start with tracing enabled, as if
+ptrace(PT_TRACE_ME, 0, 0, 0) had been invoked in the child.
+.It Dv FORK_THREAD
+The child will instead be a kernel-level thread in the same process
+as the parent.
+.Dv FORK_NOZOMBIE ,
+.Dv FORK_SHAREVM ,
+and
+.Dv FORK_SIGHAND
+must also be set.
+If the kernel option RTHREADS isn't enabled then the call will return
+.Dv ENOTSUP .
 .El
 .Pp
 If