Fixed privdata introspection for User.hasPassword and User.hasSomePassword

This is not a complete fix for the problem that Info doen't propigate
from the called property when code does something like:

	do
		hostname <- asks hostName
		ensureProperty $ foo hostname

Instead, I just eliminated the need to implement hasPassword that way,
by making the PrivData Info use a HostContext which automatically
gets the right hostname passed to it.

All other uses of withPrivData don't have the problem. It's still possible
for the user to run into the problem if they write something like the
above, where foo is a property that uses privdata. However, all properties
that take a Context now also accept a HostContext, so it's at least less
likely the user needs to write that.

debian/changelog

@@ -30,6 +30,7 @@ propellor (1.1.0) UNRELEASED; urgency=medium
   * Run apt-cache policy with LANG=C so it works on other locales.
   * endAction can be used to register an action to run once propellor
     has successfully run on a host.
+  * Fixed privdata introspection for User.hasPassword and User.hasSomePassword
 
  -- Joey Hess <joeyh@debian.org>  Sat, 22 Nov 2014 00:12:35 -0400
 

src/Propellor.hs

@@ -36,6 +36,7 @@ module Propellor (
 	, module Propellor.Host
 	, module Propellor.Info
 	, module Propellor.PrivData
+	, module Propellor.Types.PrivData
 	, module Propellor.Engine
 	, module Propellor.Exception
 	, module Propellor.Message
@@ -49,6 +50,7 @@ import Propellor.Property
 import Propellor.Engine
 import Propellor.Property.Cmd
 import Propellor.PrivData
+import Propellor.Types.PrivData
 import Propellor.Message
 import Propellor.Exception
 import Propellor.Info

src/Propellor/PrivData.hs

@@ -15,6 +15,7 @@ import qualified Data.Map as M
 import qualified Data.Set as S
 
 import Propellor.Types
+import Propellor.Types.PrivData
 import Propellor.Message
 import Propellor.Info
 import Propellor.Gpg
@@ -30,7 +31,7 @@ import Utility.Env
 import Utility.Table
 
 -- | Allows a Property to access the value of a specific PrivDataField,
--- for use in a specific Context.
+-- for use in a specific Context or HostContext.
 --
 -- Example use:
 --
@@ -47,20 +48,26 @@ import Utility.Table
 -- being used, which is necessary to ensure that the privdata is sent to
 -- the remote host by propellor.
 withPrivData
-	:: PrivDataField
-	-> Context
+	:: IsContext c
+	=> PrivDataField
+	-> c
 	-> (((PrivData -> Propellor Result) -> Propellor Result) -> Property)
 	-> Property
-withPrivData field context@(Context cname) mkprop = addinfo $ mkprop $ \a ->
-	maybe missing a =<< liftIO (getLocalPrivData field context)
+withPrivData field c mkprop = addinfo $ mkprop $ \a ->
+	maybe missing a =<< get
   where
-	missing = liftIO $ do
+  	get = do
+		context <- mkHostContext hc <$> asks hostName
+		liftIO $ getLocalPrivData field context
+	missing = do
+		Context cname <- mkHostContext hc <$> asks hostName
 		warningMessage $ "Missing privdata " ++ show field ++ " (for " ++ cname ++ ")"
-		putStrLn $ "Fix this by running: propellor --set '" ++ show field ++ "' '" ++ cname ++ "'"
+		liftIO $ putStrLn $ "Fix this by running: propellor --set '" ++ show field ++ "' '" ++ cname ++ "'"
 		return FailedChange
-	addinfo p = p { propertyInfo = propertyInfo p <> mempty { _privDataFields = S.singleton (field, context) } }
+	addinfo p = p { propertyInfo = propertyInfo p <> mempty { _privDataFields = S.singleton (field, hc) } }
+	hc = asHostContext c
 
-addPrivDataField :: (PrivDataField, Context) -> Property
+addPrivDataField :: (PrivDataField, HostContext) -> Property
 addPrivDataField v = pureInfoProperty (show v) $
 	mempty { _privDataFields = S.singleton v }
 
@@ -78,7 +85,8 @@ type PrivMap = M.Map (PrivDataField, Context) PrivData
 filterPrivData :: Host -> PrivMap -> PrivMap
 filterPrivData host = M.filterWithKey (\k _v -> S.member k used)
   where
-	used = _privDataFields $ hostInfo host
+	used = S.map (\(f, c) -> (f, mkHostContext c (hostName host))) $
+		_privDataFields $ hostInfo host
 
 getPrivData :: PrivDataField -> Context -> PrivMap -> Maybe PrivData
 getPrivData field context = M.lookup (field, context)
@@ -119,7 +127,7 @@ listPrivDataFields hosts = do
 		, shellEscape context
 		, intercalate ", " $ sort $ fromMaybe [] $ M.lookup k usedby
 		]
-	mkhostmap host = M.fromList $ map (\k -> (k, [hostName host])) $
+	mkhostmap host = M.fromList $ map (\(f, c) -> ((f, mkHostContext c (hostName host)), [hostName host])) $
 		S.toList $ _privDataFields $ hostInfo host
 	usedby = M.unionsWith (++) $ map mkhostmap hosts
 	wantedmap = M.fromList $ zip (M.keys usedby) (repeat "")

src/Propellor/Property/File.hs

@@ -17,17 +17,17 @@ f `hasContent` newcontent = fileProperty ("replace " ++ f)
 --
 -- The file's permissions are preserved if the file already existed.
 -- Otherwise, they're set to 600.
-hasPrivContent :: FilePath -> Context -> Property
+hasPrivContent :: IsContext c => FilePath -> c -> Property
 hasPrivContent = hasPrivContent' writeFileProtected
 
 -- | Leaves the file at its default or current mode,
 -- allowing "private" data to be read.
 --
 -- Use with caution!
-hasPrivContentExposed :: FilePath -> Context -> Property
+hasPrivContentExposed :: IsContext c => FilePath -> c -> Property
 hasPrivContentExposed = hasPrivContent' writeFile
 
-hasPrivContent' :: (String -> FilePath -> IO ()) -> FilePath -> Context -> Property
+hasPrivContent' :: IsContext c => (String -> FilePath -> IO ()) -> FilePath -> c -> Property
 hasPrivContent' writer f context = 
 	withPrivData (PrivFile f) context $ \getcontent -> 
 		property desc $ getcontent $ \privcontent -> 

src/Propellor/Property/Ssh.hs

@@ -88,7 +88,7 @@ hostKeys ctx = propertyList "known ssh host keys"
 	]
 
 -- | Sets a single ssh host key from the privdata.
-hostKey :: SshKeyType -> Context -> Property
+hostKey :: IsContext c => SshKeyType -> c -> Property
 hostKey keytype context = combineProperties desc
 	[ installkey (SshPubKey keytype "")  (install writeFile ".pub")
 	, installkey (SshPrivKey keytype "") (install writeFileProtected "")
@@ -107,7 +107,7 @@ hostKey keytype context = combineProperties desc
 
 -- | Sets up a user with a ssh private key and public key pair from the
 -- PrivData.
-keyImported :: SshKeyType -> UserName -> Context -> Property
+keyImported :: IsContext c => SshKeyType -> UserName -> c -> Property
 keyImported keytype user context = combineProperties desc
 	[ installkey (SshPubKey keytype user) (install writeFile ".pub")
 	, installkey (SshPrivKey keytype user) (install writeFileProtected "")
@@ -158,7 +158,7 @@ knownHost hosts hn user = property desc $
 -- | Makes a user have authorized_keys from the PrivData
 --
 -- This removes any other lines from the file.
-authorizedKeys :: UserName -> Context -> Property
+authorizedKeys :: IsContext c => UserName -> c -> Property
 authorizedKeys user context = withPrivData (SshAuthorizedKeys user) context $ \get ->
 	property (user ++ " has authorized_keys") $ get $ \v -> do
 		f <- liftIO $ dotFile "authorized_keys" user

src/Propellor/Property/Tor.hs

@@ -44,7 +44,7 @@ hiddenService hn port = mainConfig `File.containsLines`
 	`describe` unwords ["hidden service available:", hn, show port]
 	`onChange` restarted
 
-hiddenServiceData :: HiddenServiceName -> Context -> Property
+hiddenServiceData :: IsContext c => HiddenServiceName -> c -> Property
 hiddenServiceData hn context = combineProperties desc
 	[ installonion "hostname"
 	, installonion "private_key"

src/Propellor/Property/User.hs

@@ -25,34 +25,32 @@ nuked user _ = check (isJust <$> catchMaybeIO (homedir user)) $ cmdProperty "use
 -- | Only ensures that the user has some password set. It may or may
 -- not be the password from the PrivData.
 hasSomePassword :: UserName -> Property
-hasSomePassword user = property (user ++ "has password") $ do
-	hostname <- asks hostName
-	ensureProperty $ hasSomePassword' user (Context hostname)
+hasSomePassword user = hasSomePassword' user hostContext
 
 -- | While hasSomePassword uses the name of the host as context,
 -- this allows specifying a different context. This is useful when
 -- you want to use the same password on multiple hosts, for example.
-hasSomePassword' :: UserName -> Context -> Property
+hasSomePassword' :: IsContext c => UserName -> c -> Property
 hasSomePassword' user context = check ((/= HasPassword) <$> getPasswordStatus user) $
 	hasPassword' user context
 
 -- | Ensures that a user's password is set to the password from the PrivData.
 -- (Will change any existing password.)
 hasPassword :: UserName -> Property
-hasPassword user = property (user ++ "has password") $ do
-	hostname <- asks hostName
-	ensureProperty $ hasPassword' user (Context hostname)
+hasPassword user = hasPassword' user hostContext
 
-hasPassword' :: UserName -> Context -> Property
+hasPassword' :: IsContext c => UserName -> c -> Property
 hasPassword' user context = go `requires` shadowConfig True
   where
-	go = withPrivData (Password user) context $ \getpassword ->
-		property (user ++ " has password") $
-			getpassword $ \password -> makeChange $
-				withHandle StdinHandle createProcessSuccess
-					(proc "chpasswd" []) $ \h -> do
-						hPutStrLn h $ user ++ ":" ++ password
-						hClose h
+	go = withPrivData (Password user) context $
+		property (user ++ " has password") . setPassword user
+
+setPassword :: UserName -> ((PrivData -> Propellor Result) -> Propellor Result) -> Propellor Result
+setPassword user getpassword = getpassword $ \password -> makeChange $
+	withHandle StdinHandle createProcessSuccess
+		(proc "chpasswd" []) $ \h -> do
+			hPutStrLn h $ user ++ ":" ++ password
+			hClose h
 
 lockedPassword :: UserName -> Property
 lockedPassword user = check (not <$> isLockedPassword user) $ cmdProperty "passwd"

src/Propellor/Types.hs

@@ -165,7 +165,7 @@ data CmdLine
 -- | Information about a host.
 data Info = Info
 	{ _os :: Val System
-	, _privDataFields :: S.Set (PrivDataField, Context)
+	, _privDataFields :: S.Set (PrivDataField, HostContext)
 	, _sshPubKey :: Val String
 	, _aliases :: S.Set HostName
 	, _dns :: S.Set Dns.Record

src/Propellor/Types/PrivData.hs

@@ -15,7 +15,7 @@ data PrivDataField
 	| GpgKey
 	deriving (Read, Show, Ord, Eq)
 
--- | Context in which a PrivDataField is used.
+-- | A context in which a PrivDataField is used.
 --
 -- Often this will be a domain name. For example, 
 -- Context "www.example.com" could be used for the SSL cert
@@ -24,10 +24,39 @@ data PrivDataField
 newtype Context = Context String
 	deriving (Read, Show, Ord, Eq)
 
+-- | A context that varies depending on the HostName where it's used.
+newtype HostContext = HostContext { mkHostContext :: HostName -> Context }
+
+instance Show HostContext where
+	show hc = show $ mkHostContext hc "<hostname>"
+
+instance Ord HostContext where
+	a <= b = show a <= show b
+
+instance Eq HostContext where
+	a == b = show a == show b
+
+-- | Class of things that can be used as a Context.
+class IsContext c where
+	asContext :: HostName -> c -> Context
+	asHostContext :: c -> HostContext
+
+instance IsContext HostContext where
+	asContext = flip mkHostContext
+	asHostContext = id
+
+instance IsContext Context where
+	asContext _ c = c
+	asHostContext = HostContext . const
+
 -- | Use when a PrivDataField is not dependent on any paricular context.
 anyContext :: Context
 anyContext = Context "any"
 
+-- | Makes a HostContext that consists just of the hostname.
+hostContext :: HostContext
+hostContext = HostContext Context
+
 type PrivData = String
 
 data SshKeyType = SshRsa | SshDsa | SshEcdsa | SshEd25519