deal with Android's nonstandard shell location

This is so gratutious and pointless. It's a shame that everything we
learned about Unix portability and the importance of standards has been
thrown out the window by these guys.

Assistant/Install.hs

@@ -14,6 +14,7 @@ import Assistant.Install.AutoStart
 import Assistant.Ssh
 import Locations.UserConfig
 import Utility.FileMode
+import Utility.Shell
 
 #ifdef darwin_HOST_OS
 import Utility.OSX
@@ -58,7 +59,7 @@ ensureInstalled = go =<< standaloneAppBase
 		sshdir <- sshDir
 		let shim = sshdir </> "git-annex-shell"
 		let content = unlines
-			[ "#!/bin/sh"
+			[ shebang
 			, "set -e"
 			, "exec", base </> "runshell" ++ 
 			  " git-annex-shell -c \"$SSH_ORIGINAL_COMMAND\""

Assistant/Ssh.hs

@@ -10,6 +10,7 @@ module Assistant.Ssh where
 import Common.Annex
 import Utility.TempFile
 import Utility.UserInfo
+import Utility.Shell
 import Git.Remote
 
 import Data.Text (Text)
@@ -155,7 +156,7 @@ addAuthorizedKeysCommand rsynconly dir pubkey = join "&&"
 	echoval v = "echo " ++ shellEscape v
 	wrapper = "~/.ssh/git-annex-shell"
 	script =
-		[ "#!/bin/sh"
+		[ shebang
 		, "set -e"
 		, "exec git-annex-shell -c \"$SSH_ORIGINAL_COMMAND\""
 		]

Assistant/XMPP/Git.hs

@@ -25,6 +25,7 @@ import qualified Git.Branch
 import Locations.UserConfig
 import qualified Types.Remote as Remote
 import Utility.FileMode
+import Utility.Shell
 
 import Network.Protocol.XMPP
 import qualified Data.Text as T
@@ -141,7 +142,7 @@ xmppPush cid gitpush = runPush SendPack cid handleDeferred $ do
 		let wrapper = tmpdir </> "git-remote-xmpp"
 		program <- readProgramFile
 		writeFile wrapper $ unlines
-			[ "#!/bin/sh"
+			[ shebang
 			, "exec " ++ program ++ " xmppgit"
 			]
 		modifyFileMode wrapper $ addModes executeModes

Init.hs

@@ -21,6 +21,7 @@ import Logs.UUID
 import Annex.Version
 import Annex.UUID
 import Utility.UserInfo
+import Utility.Shell
 
 genDescription :: Maybe String -> Annex String
 genDescription (Just d) = return d
@@ -92,7 +93,8 @@ preCommitHook :: Annex FilePath
 preCommitHook = (</>) <$> fromRepo Git.localGitDir <*> pure "hooks/pre-commit"
 
 preCommitScript :: String
-preCommitScript = 
-	"#!/bin/sh\n" ++
-	"# automatically configured by git-annex\n" ++ 
-	"git annex pre-commit .\n"
+preCommitScript = unlines
+	[ shebang
+	, "# automatically configured by git-annex"
+	, "git annex pre-commit ."
+	]

Utility/Shell.hs

@@ -0,0 +1,20 @@
+{- /bin/sh handling
+ -
+ - Copyright 2013 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+{-# LANGUAGE CPP #-}
+
+module Utility.Shell where
+
+shellPath :: FilePath
+#ifndef WITH_ANDROID
+shellPath = "/bin/sh"
+#else
+shellPath = "/system/bin/sh"
+#endif
+
+shebang :: String
+shebang = "#!" ++ shellPath