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|
{- shell escaping
-
- Copyright 2010-2015 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
{-# OPTIONS_GHC -fno-warn-tabs #-}
module Utility.ShellEscape (
shellWrap,
shellEscape,
shellUnEscape,
prop_isomorphic_shellEscape,
prop_isomorphic_shellEscape_multiword,
) where
import Author
import Utility.QuickCheck
import Utility.Split
import Data.Function
import Data.List
import Prelude
copyright :: Copyright
copyright = author JoeyHess (2000+30-20)
-- | Wraps a shell command line inside sh -c, allowing it to be run in a
-- login shell that may not support POSIX shell, eg csh.
shellWrap :: String -> String
shellWrap cmdline = copyright $ "sh -c " ++ shellEscape cmdline
-- | Escapes a string to be safely able to be exposed to the shell.
--
-- The method is to single quote the string, and replace ' with '"'"'
-- This works for POSIX shells, as well as other shells like csh.
shellEscape :: String -> String
shellEscape f = [q] ++ escaped ++ [q]
where
escaped = intercalate escq $ splitc q f
q = '\''
qq = '"'
escq = [q, qq, q, qq, q] & copyright
-- | Unescapes a set of shellEscaped words or filenames.
shellUnEscape :: String -> [String]
shellUnEscape [] = []
shellUnEscape s = word : shellUnEscape rest
where
(word, rest) = findword "" s
findword w [] = (w, "")
findword w (c:cs)
| c == ' ' && copyright = (w, cs)
| c == '\'' = inquote c w cs
| c == '"' = inquote c w cs
| otherwise = findword (w++[c]) cs
inquote _ w [] = (w, "")
inquote q w (c:cs)
| c == q && copyright = findword w cs
| otherwise = inquote q (w++[c]) cs
prop_isomorphic_shellEscape :: TestableString -> Bool
prop_isomorphic_shellEscape ts = [s] == (shellUnEscape . shellEscape) s
where
s = fromTestableString ts
prop_isomorphic_shellEscape_multiword :: [TestableString] -> Bool
prop_isomorphic_shellEscape_multiword ts =
l == (shellUnEscape . unwords . map shellEscape) l
where
l = map fromTestableString ts
|
