Use ByteString for GroupEntry/UserEntry

No PosixString instance for now. Not sure
if it's interesting.

Author: hasufell

System/Posix/User.hsc

@@ -1,4 +1,4 @@
-{-# LANGUAGE Trustworthy, CApiFFI #-}
+{-# LANGUAGE Trustworthy, CApiFFI, PatternSynonyms, ViewPatterns #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  System.Posix.User
@@ -25,13 +25,25 @@ module System.Posix.User (
     getEffectiveUserName,
 
     -- *** The group database
-    GroupEntry(..),
+    groupName,
+    groupPassword,
+    groupID,
+    groupMembers,
+    pattern GroupEntry,
     getGroupEntryForID,
     getGroupEntryForName,
     getAllGroupEntries,
 
     -- *** The user database
-    UserEntry(..),
+    userName,
+    userPassword,
+    userID,
+    userGroupID,
+    userGecos,
+    homeDirectory,
+    userShell,
+    pattern UserEntry,
+
     getUserEntryForID,
     getUserEntryForName,
     getAllUserEntries,
@@ -53,6 +65,12 @@ import Foreign.C
 import Foreign.Ptr
 import Foreign.Marshal
 import Foreign.Storable
+import System.Posix.User.Common ( UserEntry, GroupEntry
+#if defined(HAVE_PWD_H)
+      , unpackUserEntry, unpackGroupEntry, LKUPTYPE(..), CPasswd, CGroup
+#endif
+  )
+import qualified System.Posix.User.Common as User
 
 #if defined(HAVE_GETPWENT) || defined(HAVE_GETGRENT)
 #if defined(freebsd_HOST_OS)
@@ -63,19 +81,13 @@ import Control.Exception
 #endif
 import Control.Monad
 import System.IO.Error
+import qualified Data.ByteString.Char8 as C8
 
 #if !defined(HAVE_PWD_H)
 import System.IO.Error ( ioeSetLocation )
 import GHC.IO.Exception ( unsupportedOperation )
 #endif
 
-#if defined(HAVE_PWD_H)
-
--- internal types
-data {-# CTYPE "struct passwd" #-} CPasswd
-data {-# CTYPE "struct group"  #-} CGroup
-
-#endif // HAVE_PWD_H
 
 #if !defined(HAVE_PWD_H)
 
@@ -204,7 +216,6 @@ getEffectiveUserName = ioError (ioeSetLocation unsupportedOperation "getEffectiv
 -- lot of complexity by deprecating the "get all" functions and simply
 -- always returning an empty list.
 --
-data LKUPTYPE = GETONE | GETALL
 
 #if defined(HAVE_GETPWENT)
 pwlock :: MVar ()
@@ -371,13 +382,28 @@ getEffectiveUserName = do
 -- -----------------------------------------------------------------------------
 -- The group database (grp.h)
 
-data GroupEntry =
- GroupEntry {
-  groupName    :: String,       -- ^ The name of this group (gr_name)
-  groupPassword :: String,      -- ^ The password for this group (gr_passwd)
-  groupID      :: GroupID,      -- ^ The unique numeric ID for this group (gr_gid)
-  groupMembers :: [String]      -- ^ A list of zero or more usernames that are members (gr_mem)
- } deriving (Show, Read, Eq)
+groupName :: GroupEntry -> String
+groupName (GroupEntry gn _ _ _) = gn
+
+groupPassword :: GroupEntry -> String
+groupPassword (GroupEntry _ gp _ _) = gp
+
+groupID :: GroupEntry -> GroupID
+groupID (GroupEntry _ _ id' _) = id'
+
+groupMembers :: GroupEntry -> [String]
+groupMembers (GroupEntry _ _ _ gm) = gm
+
+-- | Manually constructing 'GroupEntry' in String modules is discouraged. It will truncate
+-- Chars to 8bit. Use 'System.Posix.User.ByteString' instead.
+pattern GroupEntry :: String          -- ^ The name of this group (gr_name)
+                   -> String          -- ^ The password for this group (gr_passwd)
+                   -> GroupID         -- ^ The unique numeric ID for this group (gr_gid)
+                   -> [String]        -- ^ A list of zero or more usernames that are members (gr_mem)
+                   -> GroupEntry
+pattern GroupEntry gn gp gi gm <- User.GroupEntry (C8.unpack -> gn) (C8.unpack -> gp) gi (fmap C8.unpack -> gm) where
+  GroupEntry gn gp gi gm = User.GroupEntry (C8.pack gn) (C8.pack gp) gi (C8.pack <$> gm)
+{-# COMPLETE GroupEntry #-}
 
 #if !defined(HAVE_PWD_H)
 
@@ -474,30 +500,57 @@ grBufSize = 1024
 #endif
 #endif
 
-unpackGroupEntry :: Ptr CGroup -> IO GroupEntry
-unpackGroupEntry ptr = do
-   name    <- (#peek struct group, gr_name) ptr >>= peekCAString
-   passwd  <- (#peek struct group, gr_passwd) ptr >>= peekCAString
-   gid     <- (#peek struct group, gr_gid) ptr
-   mem     <- (#peek struct group, gr_mem) ptr
-   members <- peekArray0 nullPtr mem >>= mapM peekCAString
-   return (GroupEntry name passwd gid members)
-
 #endif // HAVE_PWD_H
 
 -- -----------------------------------------------------------------------------
 -- The user database (pwd.h)
 
-data UserEntry =
- UserEntry {
-   userName      :: String,     -- ^ Textual name of this user (pw_name)
-   userPassword  :: String,     -- ^ Password -- may be empty or fake if shadow is in use (pw_passwd)
-   userID        :: UserID,     -- ^ Numeric ID for this user (pw_uid)
-   userGroupID   :: GroupID,    -- ^ Primary group ID (pw_gid)
-   userGecos     :: String,     -- ^ Usually the real name for the user (pw_gecos)
-   homeDirectory :: String,     -- ^ Home directory (pw_dir)
-   userShell     :: String      -- ^ Default shell (pw_shell)
- } deriving (Show, Read, Eq)
+userName :: UserEntry -> String
+userName (UserEntry n _ _ _ _ _ _) = n
+
+userPassword :: UserEntry -> String
+userPassword (UserEntry _ p _ _ _ _ _) = p
+
+userID :: UserEntry -> UserID
+userID (UserEntry _ _ id' _ _ _ _) = id'
+
+userGroupID :: UserEntry -> GroupID
+userGroupID (UserEntry _ _ _ gid _ _ _) = gid
+
+userGecos :: UserEntry -> String
+userGecos (UserEntry _ _ _ _ ge _ _) = ge
+
+homeDirectory :: UserEntry -> String
+homeDirectory (UserEntry _ _ _ _ _ hd _) = hd
+
+userShell :: UserEntry -> String
+userShell (UserEntry _ _ _ _ _ _ us) = us
+
+-- | Manually constructing 'UserEntry' in String modules is discouraged. It will truncate
+-- Chars to 8bit. Use 'System.Posix.User.ByteString' instead.
+pattern UserEntry :: String         -- ^ Textual name of this user (pw_name)
+                  -> String         -- ^ Password -- may be empty or fake if shadow is in use (pw_passwd)
+                  -> UserID         -- ^ Numeric ID for this user (pw_uid)
+                  -> GroupID        -- ^ Primary group ID (pw_gid)
+                  -> String         -- ^ Usually the real name for the user (pw_gecos)
+                  -> String         -- ^ Home directory (pw_dir)
+                  -> String         -- ^ Default shell (pw_shell)
+                  -> UserEntry
+pattern UserEntry un up ui ugi ug hd us <- User.UserEntry (C8.unpack -> un)
+                                                       (C8.unpack -> up)
+                                                       ui
+                                                       ugi
+                                                       (C8.unpack -> ug)
+                                                       (C8.unpack -> hd)
+                                                       (C8.unpack -> us) where
+  UserEntry un up ui ugi ug hd us = User.UserEntry (C8.pack un)
+                                                (C8.pack up)
+                                                ui
+                                                ugi
+                                                (C8.pack ug)
+                                                (C8.pack hd)
+                                                (C8.pack us)
+{-# COMPLETE UserEntry #-}
 
 -- | @getUserEntryForID uid@ calls @getpwuid_r@ to obtain
 --   the @UserEntry@ information associated with @UserID@
@@ -621,20 +674,6 @@ doubleAllocWhileERANGE loc enttype initlen unpack action =
     ioError $ flip ioeSetErrorString ("no such " ++ enttype)
             $ mkIOError doesNotExistErrorType loc Nothing Nothing
 
-unpackUserEntry :: Ptr CPasswd -> IO UserEntry
-unpackUserEntry ptr = do
-   name   <- (#peek struct passwd, pw_name)   ptr >>= peekCAString
-   passwd <- (#peek struct passwd, pw_passwd) ptr >>= peekCAString
-   uid    <- (#peek struct passwd, pw_uid)    ptr
-   gid    <- (#peek struct passwd, pw_gid)    ptr
-#ifdef HAVE_NO_PASSWD_PW_GECOS
-   gecos  <- return ""  -- pw_gecos does not exist on android
-#else
-   gecos  <- (#peek struct passwd, pw_gecos)  ptr >>= peekCAString
-#endif
-   dir    <- (#peek struct passwd, pw_dir)    ptr >>= peekCAString
-   shell  <- (#peek struct passwd, pw_shell)  ptr >>= peekCAString
-   return (UserEntry name passwd uid gid gecos dir shell)
 
 -- Used when a function returns NULL to indicate either an error or
 -- EOF, depending on whether the global errno is nonzero.