From 983ee62929037c7297e2281ea3910e94a85bead5 Mon Sep 17 00:00:00 2001 From: Joey Hess Date: Mon, 10 Apr 2017 10:52:33 -0400 Subject: reorg --- src/Propellor/Property/Chroot.hs | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) (limited to 'src/Propellor/Property/Chroot.hs') diff --git a/src/Propellor/Property/Chroot.hs b/src/Propellor/Property/Chroot.hs index 7738d97e..96c75846 100644 --- a/src/Propellor/Property/Chroot.hs +++ b/src/Propellor/Property/Chroot.hs @@ -11,6 +11,7 @@ module Propellor.Property.Chroot ( ChrootTarball(..), noServices, inChroot, + exposeTrueLocaldir, -- * Internal use provisioned', propagateChrootInfo, @@ -295,6 +296,38 @@ setInChroot h = h { hostInfo = hostInfo h `addInfo` InfoVal (InChroot True) } newtype InChroot = InChroot Bool deriving (Typeable, Show) +-- | Runs an action with the true localdir exposed, +-- not the one bind-mounted into a chroot. The action is passed the +-- path containing the contents of the localdir outside the chroot. +-- +-- In a chroot, this is accomplished by temporily bind mounting the localdir +-- to a temp directory, to preserve access to the original bind mount. Then +-- we unmount the localdir to expose the true localdir. Finally, to cleanup, +-- the temp directory is bind mounted back to the localdir. +exposeTrueLocaldir :: (FilePath -> IO a) -> Propellor a +exposeTrueLocaldir a = ifM inChroot + ( liftIO $ withTmpDirIn (takeDirectory localdir) "propellor.tmp" $ \tmpdir -> + bracket_ + (movebindmount localdir tmpdir) + (movebindmount tmpdir localdir) + (a tmpdir) + , liftIO $ a localdir + ) + where + movebindmount from to = do + run "mount" [Param "--bind", File from, File to] + -- Have to lazy unmount, because the propellor process + -- is running in the localdir that it's unmounting.. + run "umount" [Param "-l", File from] + -- We were in the old localdir; move to the new one after + -- flipping the bind mounts. Otherwise, commands that try + -- to access the cwd will fail because it got umounted out + -- from under. + changeWorkingDirectory "/" + changeWorkingDirectory localdir + run cmd ps = unlessM (boolSystem cmd ps) $ + error $ "exposeTrueLocaldir failed to run " ++ show (cmd, ps) + -- | Generates a Chroot that has all the properties of a Host. -- -- Note that it's possible to create loops using this, where a host -- cgit v1.2.3