propellor spin

1 files changed, 62 insertions, 0 deletions

diff --git a/src/Propellor/Shim.hs b/src/Propellor/Shim.hs
new file mode 100644
index 00000000..5b5aa68e
--- /dev/null
+++ b/src/Propellor/Shim.hs
@@ -0,0 +1,62 @@
+-- | Support for running propellor, as built outside a container,
+-- inside the container, without needing to install anything into the
+-- container.
+--
+-- Note: This is currently Debian specific, due to glibcLibs.
+
+module Propellor.Shim (setup, cleanEnv, file) where
+
+import Propellor
+import Utility.LinuxMkLibs
+import Utility.SafeCommand
+import Utility.Path
+import Utility.FileMode
+
+import Data.List
+import System.Posix.Files
+
+-- | Sets up a shimmed version of the program, in a directory, and
+-- returns its path.
+setup :: FilePath -> FilePath -> IO FilePath
+setup propellorbin dest = do
+	createDirectoryIfMissing True dest
+
+	libs <- parseLdd <$> readProcess "ldd" [propellorbin]
+	glibclibs <- glibcLibs
+	let libs' = nub $ libs ++ glibclibs
+	libdirs <- map (dest ++) . nub . catMaybes
+		<$> mapM (installLib installFile dest) libs'
+	
+	let linker = (dest ++) $ 
+		fromMaybe (error "cannot find ld-linux linker") $
+			headMaybe $ filter ("ld-linux" `isInfixOf`) libs'
+	let gconvdir = (dest ++) $ parentDir $
+		fromMaybe (error "cannot find gconv directory") $
+			headMaybe $ filter ("/gconv/" `isInfixOf`) glibclibs
+	let linkerparams = ["--library-path", intercalate ":" libdirs ]
+	let shim = file propellorbin dest
+	writeFile shim $ unlines
+		[ "#!/bin/sh"
+		, "GCONV_PATH=" ++ shellEscape gconvdir
+		, "export GCONV_PATH"
+		, "exec " ++ unwords (map shellEscape $ linker : linkerparams) ++ 
+			" " ++ shellEscape propellorbin ++ " \"$@\""
+		]
+	modifyFileMode shim (addModes executeModes)
+	return shim
+
+cleanEnv :: IO ()
+cleanEnv = void $ unsetEnv "GCONV_PATH"
+
+file :: FilePath -> FilePath -> FilePath
+file propellorbin dest = dest </> takeFileName propellorbin
+
+installFile :: FilePath -> FilePath -> IO ()
+installFile top f = do
+	createDirectoryIfMissing True destdir
+	nukeFile dest
+	createLink f dest `catchIO` (const copy)
+  where
+	copy = void $ boolSystem "cp" [Param "-a", Param f, Param dest]
+	destdir = inTop top $ parentDir f
+	dest = inTop top f