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{-# LANGUAGE TemplateHaskell #-}
module UTmp
( users
, users2
, utmp_file
, UserName
, Tty
, ProcessID
, UtmpRecord(..)
, UT_Type(..)
) where
import qualified Data.ByteString as S
import qualified Data.ByteString.Char8 as C
import qualified Data.ByteString.Lazy.Char8 as L
import Data.BitSyntax
import Data.Functor.Identity
import Data.Maybe
import System.Posix.Signals
import System.Posix.Types
import Control.Monad
import Data.Word
import Data.Int
import Control.Monad.Error.Class
import System.IO.Error
import qualified Paths
import Data.Text ( Text )
import Unsafe.Coerce ( unsafeCoerce )
import Network.Socket ( SockAddr(..) )
import qualified Data.Text.Encoding as Text
utmp_file = Paths.utmp -- "/var/run/utmp"
utmp_bs = S.readFile utmp_file
decode_utmp_bytestring =
runIdentity
. $(bitSyn [ UnsignedLE 4 -- type
, UnsignedLE 4 -- pid
, Fixed 32 -- tty
, Fixed 4 -- inittab id
, Fixed 32 -- username
, Fixed 256 -- remote host
, UnsignedLE 2 -- termination status
, UnsignedLE 2 -- exit status (int)
, UnsignedLE 4 -- session id (int)
, Fixed 8 -- time entry was made
, Unsigned 4 -- remote addr v6 addr[0]
, Unsigned 4 -- remote addr v6 addr[1]
, Unsigned 4 -- remote addr v6 addr[2]
, Unsigned 4 -- remote addr v6 addr[3]
, Skip 20 -- reserved
])
utmp_size = 384 -- 768
utmp_records bs | S.length bs >= utmp_size
= u:utmp_records us
where
(u,us) = S.splitAt utmp_size bs
utmp_records bs = [bs]
utmp = fmap (map decode_utmp_bytestring . utmp_records) utmp_bs
toStr = takeWhile (/='\0') . C.unpack
interp_utmp_record (typ,pid,tty,inittab,user,hostv4,term,exit,session,time
,addr0,addr1,addr2,addr3) =
( (toEnum . fromIntegral) typ :: UT_Type
, toStr user, toStr tty, processId pid, toStr hostv4 )
where
processId = CPid . coerceToSigned
coerceToSigned :: Word32 -> Int32
coerceToSigned = unsafeCoerce
data UT_Type
= EMPTY -- No valid user accounting information. */
| RUN_LVL -- The system's runlevel. */
| BOOT_TIME -- Time of system boot. */
| NEW_TIME -- Time after system clock changed. */
| OLD_TIME -- Time when system clock changed. */
| INIT_PROCESS -- Process spawned by the init process. */
| LOGIN_PROCESS -- Session leader of a logged in user. */
| USER_PROCESS -- Normal process. */
| DEAD_PROCESS -- Terminated process. */
| ACCOUNTING
deriving (Enum,Show,Eq,Ord,Read)
processAlive pid = do
catchError (do { signalProcess nullSignal pid ; return True })
$ \e -> do { return (not ( isDoesNotExistError e)); }
type UserName = L.ByteString
type Tty = L.ByteString
users :: IO [(UserName, Tty, ProcessID)]
users = fmap (map only3) $ do
us <- utmp
let us' = map interp_utmp_record us
us'' = mapMaybe user_proc us'
user_proc (USER_PROCESS, u,tty,pid, hostv4)
= Just (L.pack u,L.pack tty,pid,hostv4)
user_proc _ = Nothing
onThrd f (_,_,pid,_) = f pid
us3 <- filterM (onThrd processAlive) us''
return us3
only3 (a,b,c,_) = (a,b,c)
data UtmpRecord = UtmpRecord
{ utmpType :: UT_Type
, utmpUser :: Text
, utmpTty :: Text
, utmpPid :: CPid
, utmpHost :: Text
, utmpSession :: Int32
, utmpRemoteAddr :: Maybe SockAddr
}
deriving ( Show, Eq, Ord )
toText bs = Text.decodeUtf8 $ C.takeWhile (/='\0') bs
interp_utmp_record2 (typ,pid,tty,inittab,user,hostv4
,term,exit,session,time,addr0,addr1,addr2,addr3) =
UtmpRecord
{ utmpType = toEnum (fromIntegral typ) :: UT_Type
, utmpUser = toText user
, utmpTty = toText tty
, utmpPid = processId pid
, utmpHost = toText hostv4
, utmpSession = coerceToSigned session
, utmpRemoteAddr =
if all (==0) [addr1,addr2,addr3]
then do guard (addr0/=0)
Just $ SockAddrInet6 0 0 (0,0,0xFFFF,addr0) 0
else Just $ SockAddrInet6 0 0 (addr0,addr1,addr2,addr3) 0
}
where
processId = CPid . coerceToSigned
-- users2 :: IO [(UserName, Tty, ProcessID)]
users2 = do
us <- utmp
let us' = map interp_utmp_record2 us
us3 <- filterM (processAlive . utmpPid) us'
return us3
{-
- This is how the w command reports idle time:
/* stat the device file to get an idle time */
static time_t idletime(const char *restrict const tty)
{
struct stat sbuf;
if (stat(tty, &sbuf) != 0)
return 0;
return time(NULL) - sbuf.st_atime;
}
- THis might be useful fo rimplementing
- xep-0012 Last Activity
- iq get {jabber:iq:last}query
-
-}
|
