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|
{- lsof interface
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE BangPatterns #-}
module Utility.Lsof where
import Common
import Build.SysConfig as SysConfig
import System.Posix.Types
import System.Posix.Env
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. -}
setupLsof :: IO ()
setupLsof = do
let cmd = fromMaybe "lsof" SysConfig.lsof
when (isAbsolute cmd) $ do
path <- getSearchPath
let path' = takeDirectory cmd : path
setEnv "PATH" (join [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
parse <$> hGetContentsStrict h
where
p = proc "lsof" ("-F0can" : opts)
{- 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.
-}
parse :: String -> [(FilePath, LsofOpenMode, ProcessInfo)]
parse 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
|
