propellor/src/Propellor/Property/Hostname.hs

64 lines
2.1 KiB
Haskell

module Propellor.Property.Hostname where
import Propellor
import qualified Propellor.Property.File as File
import Data.List
-- | Ensures that the hostname is set using best practices.
--
-- Configures </etc/hostname> and the current hostname.
--
-- Configures </etc/mailname> with the domain part of the hostname.
--
-- </etc/hosts> is also configured, with an entry for 127.0.1.1, which is
-- standard at least on Debian to set the FDQN.
--
-- Also, the </etc/hosts> 127.0.0.1 line is set to localhost. Putting any
-- other hostnames there is not best practices and can lead to annoying
-- messages from eg, apache.
sane :: Property NoInfo
sane = property ("sane hostname") (ensureProperty . setTo =<< asks hostName)
setTo :: HostName -> Property NoInfo
setTo hn = combineProperties desc go
where
desc = "hostname " ++ hn
(basehost, domain) = separate (== '.') hn
go = catMaybes
[ Just $ "/etc/hostname" `File.hasContent` [basehost]
, if null domain
then Nothing
else Just $ trivial $ hostsline "127.0.1.1" [hn, basehost]
, Just $ trivial $ hostsline "127.0.0.1" ["localhost"]
, Just $ trivial $ cmdProperty "hostname" [basehost]
, Just $ "/etc/mailname" `File.hasContent`
[if null domain then hn else domain]
]
hostsline ip names = File.fileProperty desc
(addhostsline ip names)
"/etc/hosts"
addhostsline ip names ls =
(ip ++ "\t" ++ (unwords names)) : filter (not . hasip ip) ls
hasip ip l = headMaybe (words l) == Just ip
-- | Makes </etc/resolv.conf> contain search and domain lines for
-- the domain that the hostname is in.
searchDomain :: Property NoInfo
searchDomain = property desc (ensureProperty . go =<< asks hostName)
where
desc = "resolv.conf search and domain configured"
go hn =
let (_basehost, domain) = separate (== '.') hn
in File.fileProperty desc (use domain) "/etc/resolv.conf"
use domain ls = filter wanted $ nub (ls ++ cfgs)
where
cfgs = ["domain " ++ domain, "search " ++ domain]
wanted l
| l `elem` cfgs = True
| "domain " `isPrefixOf` l = False
| "search " `isPrefixOf` l = False
| otherwise = True