afa5b883dc
Note that filenames are not quoted, only escaped. This is to match the output of --format with escaping. Sponsored-by: Lawrence Brogan on Patreon
58 lines
1.3 KiB
Haskell
58 lines
1.3 KiB
Haskell
{- Safe output to the terminal of possibly attacker-controlled strings,
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- avoiding displaying control characters.
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-
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- Copyright 2023 Joey Hess <id@joeyh.name>
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-
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- License: BSD-2-clause
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-}
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{-# LANGUAGE TypeSynonymInstances, FlexibleInstances, CPP #-}
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{-# OPTIONS_GHC -fno-warn-tabs #-}
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module Utility.SafeOutput (
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safeOutput,
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IsTerminal(..),
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checkIsTerminal,
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) where
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import Data.Char
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import qualified Data.ByteString as S
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import System.IO
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#ifdef mingw32_HOST_OS
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import System.Win32.MinTTY (isMinTTYHandle)
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import System.Win32.File
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import System.Win32.Types
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import Graphics.Win32.Misc
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import Control.Exception
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#endif
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class SafeOutputtable t where
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safeOutput :: t -> t
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instance SafeOutputtable String where
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safeOutput = filter (not . isControl)
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instance SafeOutputtable S.ByteString where
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safeOutput = S.filter (not . isControl . chr . fromIntegral)
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newtype IsTerminal = IsTerminal Bool
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checkIsTerminal :: Handle -> IO IsTerminal
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checkIsTerminal h = do
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#ifndef mingw32_HOST_OS
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b <- hIsTerminalDevice h
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return (IsTerminal b)
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#else
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b <- hIsTerminalDevice h
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if b
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then return (IsTerminal b)
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else do
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h' <- getStdHandle sTD_OUTPUT_HANDLE
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`catch` \(_ :: IOError) ->
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return nullHANDLE
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if h == nullHANDLE
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then return (IsTerminal False)
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else do
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b' <- isMinTTYHandle h'
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return (IsTerminal b)
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#endif
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