Add Id module

src/Streamly/Coreutils/Id.hs

@@ -0,0 +1,103 @@
+-- |
+-- Module      : Streamly.Coreutils.Id
+-- Copyright   : (c) 2022 Composewell Technologies
+-- License     : BSD-3-Clause
+-- Maintainer  : [email protected]
+-- Stability   : experimental
+-- Portability : GHC
+--
+-- Get real and effective user and group IDs.
+
+module Streamly.Coreutils.Id
+    (
+      id
+
+    -- * Options
+    , IdOptions
+    , effectiveGroupId
+    , groups
+    , realGroupId
+    , realUserId
+    , effectiveUserId
+    , effectiveUserName
+    , realUserName
+    , IdResult(..)
+    )
+where
+
+import Data.Word (Word32)
+import System.Posix.Types (CGid(CGid), CUid(CUid))
+
+import qualified System.Posix.User as Posix
+
+import Prelude hiding (id)
+
+data IdOptions =
+      RealGroupId
+    | EffectiveGroupId
+    | Groups
+    | RealUserName
+    | EffectiveUserName
+    | RealUserId
+    | EffectiveUserId
+
+realGroupId :: IdOptions
+realGroupId = RealGroupId
+
+effectiveGroupId :: IdOptions
+effectiveGroupId = EffectiveGroupId
+
+groups :: IdOptions
+groups = Groups
+
+realUserName :: IdOptions
+realUserName = RealUserName
+
+effectiveUserName :: IdOptions
+effectiveUserName = EffectiveUserName
+
+realUserId :: IdOptions
+realUserId = RealUserId
+
+effectiveUserId :: IdOptions
+effectiveUserId = EffectiveUserId
+
+data IdResult =
+      Id Word32
+    | Ids [Word32]
+    | Name String
+        deriving Show
+
+getRealUserID :: IO Word32
+getRealUserID = do
+    CUid x <- Posix.getRealUserID
+    return x
+
+getRealGroupID :: IO Word32
+getRealGroupID = do
+    CGid x <- Posix.getRealGroupID
+    return x
+
+getEffectiveUserID :: IO Word32
+getEffectiveUserID =  do
+    CUid x <- Posix.getEffectiveUserID
+    return x
+
+getEffectiveGroupID :: IO Word32
+getEffectiveGroupID = do
+    CGid x <- Posix.getEffectiveGroupID
+    return x
+
+getGroups :: IO [Word32]
+getGroups =
+    map (\(CGid x) -> x) <$> Posix.getGroups
+
+id :: IdOptions -> IO IdResult
+id opt = case opt of
+    RealGroupId -> Id <$> getRealGroupID
+    EffectiveGroupId -> Id <$> getEffectiveGroupID
+    Groups -> Ids <$> getGroups
+    RealUserName -> Name <$> Posix.getLoginName
+    EffectiveUserName -> Name <$> Posix.getEffectiveUserName
+    RealUserId -> Id <$> getRealUserID
+    EffectiveUserId -> Id <$> getEffectiveUserID

streamly-coreutils.cabal

@@ -98,6 +98,7 @@ library
     , Streamly.Coreutils.Common
     , Streamly.Coreutils.Cp
     , Streamly.Coreutils.FileTest
+    , Streamly.Coreutils.Id
     , Streamly.Coreutils.ShellWords
     , Streamly.Coreutils.Uniq
     , Streamly.Coreutils.Which