git-annex/Utility/Lsof.hs
Joey Hess 1e59df083d Use haskell setenv library to clean up several ugly workarounds for inability to manipulate the environment on windows.
Didn't know that this library existed!

This includes making git-annex not re-exec itself on start on windows, and
making the test suite on Windows run tests without forking.
2014-10-15 20:33:52 -04:00

120 lines
3.1 KiB
Haskell

{- lsof interface
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- License: BSD-2-clause
-}
{-# LANGUAGE CPP #-}
module Utility.Lsof where
import Common
import Build.SysConfig as SysConfig
import Utility.Env
import System.Posix.Types
data LsofOpenMode = OpenReadWrite | OpenReadOnly | OpenWriteOnly | OpenUnknown
deriving (Show, Eq)
type CmdLine = String
data ProcessInfo = ProcessInfo ProcessID CmdLine
deriving (Show)
{- lsof is not in PATH on all systems, so SysConfig may have the absolute
- path where the program was found. Make sure at runtime that lsof is
- available, and if it's not in PATH, adjust PATH to contain it. -}
setup :: IO ()
setup = do
let cmd = fromMaybe "lsof" SysConfig.lsof
when (isAbsolute cmd) $ do
path <- getSearchPath
let path' = takeDirectory cmd : path
setEnv "PATH" (intercalate [searchPathSeparator] path') True
{- Checks each of the files in a directory to find open files.
- Note that this will find hard links to files elsewhere that are open. -}
queryDir :: FilePath -> IO [(FilePath, LsofOpenMode, ProcessInfo)]
queryDir path = query ["+d", path]
{- Runs lsof with some parameters.
-
- Ignores nonzero exit code; lsof returns that when no files are open.
-
- Note: If lsof is not available, this always returns [] !
-}
query :: [String] -> IO [(FilePath, LsofOpenMode, ProcessInfo)]
query opts =
withHandle StdoutHandle (createProcessChecked checkSuccessProcess) p $ \h -> do
fileEncoding h
parse <$> hGetContentsStrict h
where
p = proc "lsof" ("-F0can" : opts)
type LsofParser = String -> [(FilePath, LsofOpenMode, ProcessInfo)]
parse :: LsofParser
#ifdef __ANDROID__
parse = parseDefault
#else
parse = parseFormatted
#endif
{- Parsing null-delimited output like:
-
- pPID\0cCMDLINE\0
- aMODE\0nFILE\0
- aMODE\0nFILE\0
- pPID\0[...]
-
- Where each new process block is started by a pid, and a process can
- have multiple files open.
-}
parseFormatted :: LsofParser
parseFormatted s = bundle $ go [] $ lines s
where
bundle = concatMap (\(fs, p) -> map (\(f, m) -> (f, m, p)) fs)
go c [] = c
go c ((t:r):ls)
| t == 'p' =
let (fs, ls') = parsefiles [] ls
in go ((fs, parseprocess r):c) ls'
| otherwise = parsefail
go _ _ = parsefail
parseprocess l = case splitnull l of
[pid, 'c':cmdline, ""] ->
case readish pid of
(Just n) -> ProcessInfo n cmdline
Nothing -> parsefail
_ -> parsefail
parsefiles c [] = (c, [])
parsefiles c (l:ls) = case splitnull l of
['a':mode, 'n':file, ""] ->
parsefiles ((file, parsemode mode):c) ls
(('p':_):_) -> (c, l:ls)
_ -> parsefail
parsemode ('r':_) = OpenReadOnly
parsemode ('w':_) = OpenWriteOnly
parsemode ('u':_) = OpenReadWrite
parsemode _ = OpenUnknown
splitnull = split "\0"
parsefail = error $ "failed to parse lsof output: " ++ show s
{- Parses lsof's default output format. -}
parseDefault :: LsofParser
parseDefault = mapMaybe parseline . drop 1 . lines
where
parseline l = case words l of
(command : spid : _user : _fd : _type : _device : _size : _node : rest) ->
case readish spid of
Nothing -> Nothing
Just pid -> Just (unwords rest, OpenUnknown, ProcessInfo pid command)
_ -> Nothing