From 8a7efe723e4de97065424d1e2396fe0ce5144f56 Mon Sep 17 00:00:00 2001 From: Joey Hess Date: Sat, 11 Mar 2017 16:08:53 -0400 Subject: Implemented hostChroot As originally seen in my slides at Linux.Conf.Au 2017 in January. Now that it's not vaporware, it allows one Host to build a disk image that has all the properties of another Host. It was easier than I thought to implement this! As expected, Info propagation was slightly tricky. Also, I originally had a lot of machinery to try to use Info to detect infinitely nested chroot loops. But, my machinery didn't work, and when I tested it, ghc did a much better job, causing a "warning: <>" message to be output instead of such a property using infinite disk space. This commit was sponsored by Bruno BEAUFILS on Patreon. --- src/Propellor/Property/Chroot.hs | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'src/Propellor/Property/Chroot.hs') diff --git a/src/Propellor/Property/Chroot.hs b/src/Propellor/Property/Chroot.hs index 9624a0f3..4b9b48e1 100644 --- a/src/Propellor/Property/Chroot.hs +++ b/src/Propellor/Property/Chroot.hs @@ -1,9 +1,11 @@ {-# LANGUAGE FlexibleContexts, GADTs, DeriveDataTypeable #-} +{-# LANGUAGE GeneralizedNewtypeDeriving #-} module Propellor.Property.Chroot ( debootstrapped, bootstrapped, provisioned, + hostChroot, Chroot(..), ChrootBootstrapper(..), Debootstrapped(..), @@ -290,3 +292,22 @@ setInChroot h = h { hostInfo = hostInfo h `addInfo` InfoVal (InChroot True) } newtype InChroot = InChroot Bool deriving (Typeable, Show) + +-- | Generates a Chroot that has all the properties of a Host. +-- +-- Note that it's possible to create loops using this, where a host +-- contains a Chroot containing itself etc. Such loops will be detected at +-- runtime. +hostChroot :: ChrootBootstrapper bootstrapper => Host -> bootstrapper -> FilePath -> Chroot +hostChroot h bootstrapper d = chroot + where + chroot = Chroot d bootstrapper pinfo h + pinfo = propagateHostChrootInfo h chroot + +-- This is different than propagateChrootInfo in that Info using +-- HostContext is not made to use the name of the chroot as its context, +-- but instead uses the hostname of the Host. +propagateHostChrootInfo :: Host -> Chroot -> InfoPropagator +propagateHostChrootInfo h c p = + propagateContainer (hostName h) c $ + p `setInfoProperty` chrootInfo c -- cgit v1.2.3