142 lines
4.1 KiB
Haskell
142 lines
4.1 KiB
Haskell
{- ssh config file parsing and modification
|
||
-
|
||
- Copyright 2013 Joey Hess <id@joeyh.name>
|
||
-
|
||
- License: BSD-2-clause
|
||
-}
|
||
|
||
module Utility.SshConfig where
|
||
|
||
import Common
|
||
import Utility.UserInfo
|
||
import Utility.Tmp
|
||
import Utility.FileMode
|
||
|
||
import Data.Char
|
||
import Data.Ord
|
||
import Data.Either
|
||
|
||
data SshConfig
|
||
= GlobalConfig SshSetting
|
||
| HostConfig Host [Either Comment SshSetting]
|
||
| CommentLine Comment
|
||
deriving (Show)
|
||
|
||
data Comment = Comment Indent String
|
||
deriving (Show)
|
||
|
||
data SshSetting = SshSetting Indent Key Value
|
||
deriving (Show)
|
||
|
||
type Indent = String
|
||
type Host = String
|
||
type Key = String
|
||
type Value = String
|
||
|
||
{- Parses ~/.ssh/config. Comments and indentation are preserved.
|
||
-
|
||
- Note that there is no parse failure. If a line cannot be parsed, it will
|
||
- be taken to be a SshSetting that contains the whole line as the key,
|
||
- and has no value. -}
|
||
parseSshConfig :: String -> [SshConfig]
|
||
parseSshConfig = go [] . lines
|
||
where
|
||
go c [] = reverse c
|
||
go c (l:ls)
|
||
| iscomment l = collect $ CommentLine $ mkcomment l
|
||
| otherwise = case splitline l of
|
||
(indent, k, v)
|
||
| isHost k -> hoststanza v c [] ls
|
||
| otherwise -> collect $ GlobalConfig $ SshSetting indent k v
|
||
where
|
||
collect v = go (v:c) ls
|
||
|
||
hoststanza host c hc [] = go (HostConfig host (reverse hc):c) []
|
||
hoststanza host c hc (l:ls)
|
||
| iscomment l = hoststanza host c ((Left $ mkcomment l):hc) ls
|
||
| otherwise = case splitline l of
|
||
(indent, k, v)
|
||
| isHost k -> hoststanza v
|
||
(HostConfig host (reverse hc):c) [] ls
|
||
| otherwise -> hoststanza host c
|
||
((Right $ SshSetting indent k v):hc) ls
|
||
|
||
iscomment l = all isSpace l || "#" `isPrefixOf` (dropWhile isSpace l)
|
||
|
||
splitline l = (indent, k, v)
|
||
where
|
||
(indent, rest) = span isSpace l
|
||
(k, v) = separate isSpace rest
|
||
|
||
mkcomment l = Comment indent c
|
||
where
|
||
(indent, c) = span isSpace l
|
||
|
||
isHost v = map toLower v == "host"
|
||
|
||
genSshConfig :: [SshConfig] -> String
|
||
genSshConfig = unlines . concatMap gen
|
||
where
|
||
gen (CommentLine c) = [comment c]
|
||
gen (GlobalConfig s) = [setting s]
|
||
gen (HostConfig h cs) = ("Host " ++ h) : map (either comment setting) cs
|
||
|
||
setting (SshSetting indent k v) = indent ++ k ++ " " ++ v
|
||
comment (Comment indent c) = indent ++ c
|
||
|
||
findHostConfigKey :: SshConfig -> Key -> Maybe Value
|
||
findHostConfigKey (HostConfig _ cs) wantk = go (rights cs) (map toLower wantk)
|
||
where
|
||
go [] _ = Nothing
|
||
go ((SshSetting _ k v):rest) wantk'
|
||
| map toLower k == wantk' = Just v
|
||
| otherwise = go rest wantk'
|
||
findHostConfigKey _ _ = Nothing
|
||
|
||
{- Adds a particular Key and Value to a HostConfig. -}
|
||
addToHostConfig :: SshConfig -> Key -> Value -> SshConfig
|
||
addToHostConfig (HostConfig host cs) k v =
|
||
HostConfig host $ Right (SshSetting indent k v) : cs
|
||
where
|
||
{- The indent is taken from any existing SshSetting
|
||
- in the HostConfig (largest indent wins). -}
|
||
indent = fromMaybe "\t" $ headMaybe $ reverse $
|
||
sortBy (comparing length) $ map getindent cs
|
||
getindent (Right (SshSetting i _ _)) = i
|
||
getindent (Left (Comment i _)) = i
|
||
addToHostConfig other _ _ = other
|
||
|
||
modifyUserSshConfig :: ([SshConfig] -> [SshConfig]) -> IO ()
|
||
modifyUserSshConfig modifier = changeUserSshConfig $
|
||
genSshConfig . modifier . parseSshConfig
|
||
|
||
changeUserSshConfig :: (String -> String) -> IO ()
|
||
changeUserSshConfig modifier = do
|
||
sshdir <- sshDir
|
||
let configfile = sshdir </> "config"
|
||
whenM (doesFileExist configfile) $ do
|
||
c <- readFileStrict configfile
|
||
let c' = modifier c
|
||
when (c /= c') $
|
||
viaTmp writeSshConfig configfile c'
|
||
|
||
writeSshConfig :: FilePath -> String -> IO ()
|
||
writeSshConfig f s = do
|
||
writeFile f s
|
||
setSshConfigMode f
|
||
|
||
{- Ensure that the ssh config file lacks any group or other write bits,
|
||
- since ssh is paranoid about not working if other users can write
|
||
- to one of its config files (.ssh/config and .ssh/authorized_keys).
|
||
-
|
||
- If the chmod fails, ignore the failure, as it might be a filesystem like
|
||
- Android's that does not support file modes.
|
||
-}
|
||
setSshConfigMode :: FilePath -> IO ()
|
||
setSshConfigMode f = void $ tryIO $ modifyFileMode f $
|
||
removeModes [groupWriteMode, otherWriteMode]
|
||
|
||
sshDir :: IO FilePath
|
||
sshDir = do
|
||
home <- myHomeDir
|
||
return $ home </> ".ssh"
|