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|
{- lsof interface
-
- Copyright 2012 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
module Utility.Lsof (
LsofOpenMode(..),
setup,
queryDir,
query,
) where
import Common
import BuildInfo
import Utility.Env.Set
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 BuildInfo 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" BuildInfo.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 = withCreateProcess p go
where
p = (proc "lsof" ("-F0can" : opts))
{ std_out = CreatePipe }
go _ (Just outh) _ pid = do
r <- parse <$> hGetContentsStrict outh
void $ waitForProcess pid
return r
go _ _ _ _ = error "internal"
type LsofParser = String -> [(FilePath, LsofOpenMode, ProcessInfo)]
{- 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 :: LsofParser
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) = parsefiles' c (splitnull l) l ls
parsefiles' c ['a':mode, 'n':file, ""] _ ls =
parsefiles ((file, parsemode mode):c) ls
parsefiles' c (('p':_):_) l ls = (c, l:ls)
-- Some buggy versions of lsof emit a f field
-- that was not requested, so ignore it.
parsefiles' c (('f':_):rest) l ls = parsefiles' c rest l ls
parsefiles' _ _ _ _ = parsefail
parsemode ('r':_) = OpenReadOnly
parsemode ('w':_) = OpenWriteOnly
parsemode ('u':_) = OpenReadWrite
parsemode _ = OpenUnknown
splitnull = splitc '\0'
parsefail = error $ "failed to parse lsof output: " ++ show s
|