Add an ALRM timer to cope with 2 annoying issues in rc.d(8):

- prevent a daemon from hanging the boot
(typo in your flagsm e.g. httpd_flags=-d)
- make sure we can get the status of a backgrounded daemon instead of always
returning success

Side effect of this is that we can kill a knob! rip rc_bg :-)
Ports will need love, and a second commit is coming for that.

The diff is small yet not trivial so I am committing early in the release
process in one shot so it can easily be reverted if needed. I started working on
this during g2k16 in Cambridge then finished it in Brisbane for a2k17 where
robert@, beck@ and sthen@ agreed it was the correct way to go and I should move
ahead with it post 6.1.

If you see any regression, please talk to me!

2 files changed, 7 insertions, 24 deletions

diff --git a/share/man/man8/rc.d.8 b/share/man/man8/rc.d.8
index 64576eff7f6..a9635344f4a 100644
--- a/share/man/man8/rc.d.8
+++ b/share/man/man8/rc.d.8
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: rc.d.8,v 1.32 2017/05/25 09:40:18 ajacoutot Exp $
+.\"	$OpenBSD: rc.d.8,v 1.33 2017/05/27 13:51:52 ajacoutot Exp $
 .\"
 .\" Copyright (c) 2011 Robert Nagy, Antoine Jacoutot, Ingo Schwarze
 .\" All rights reserved.
@@ -24,7 +24,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: May 25 2017 $
+.Dd $Mdocdate: May 27 2017 $
 .Dt RC.D 8
 .Os
 .Sh NAME
@@ -115,10 +115,7 @@ Routing table to run the daemon under, using
 .Xr route 8 .
 .It Ar daemon Ns _timeout
 Maximum time in seconds to wait for the
-.Cm start
-(only if
-.Va rc_bg
-is set),
+.Cm start ,
 .Cm stop
 and
 .Cm reload
diff --git a/share/man/man8/rc.subr.8 b/share/man/man8/rc.subr.8
index 5b9c0bf1741..239aadaed9c 100644
--- a/share/man/man8/rc.subr.8
+++ b/share/man/man8/rc.subr.8
@@ -1,4 +1,4 @@
-.\" 	$OpenBSD: rc.subr.8,v 1.32 2016/09/07 13:12:42 ajacoutot Exp $
+.\" 	$OpenBSD: rc.subr.8,v 1.33 2017/05/27 13:51:52 ajacoutot Exp $
 .\"
 .\" Copyright (c) 2011 Robert Nagy, Antoine Jacoutot, Ingo Schwarze
 .\" All rights reserved.
@@ -24,7 +24,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: September 7 2016 $
+.Dd $Mdocdate: May 27 2017 $
 .Dt RC.SUBR 8
 .Os
 .Sh NAME
@@ -79,11 +79,7 @@ Override the
 .Va pexp
 variable or any of the
 .Ic rc_*
-functions and set the
-.Va rc_bg
-or
-.Va rc_reload
-variables, if needed.
+functions and variables, if needed.
 .It
 Define an
 .Ic rc_pre
@@ -252,10 +248,7 @@ Routing table to run the daemon under, using
 .Xr route 8 .
 .It Va daemon_timeout
 Maximum time in seconds to wait for the
-.Cm start
-(only if
-.Va rc_bg
-is set),
+.Cm start ,
 .Cm stop
 and
 .Cm reload
@@ -286,13 +279,6 @@ script has to redefine this variable
 .Em after
 sourcing
 .Nm .
-.It Va rc_bg
-Can be set to
-.Cm YES
-in an
-.Nm rc.d
-script to force starting the daemon in background when using the default
-.Ic rc_start .
 .It Va rc_reload
 Can be set to
 .Dq NO