--- /dev/null
+{-| Implementation of the generic daemon functionality.
+
+-}
+
+{-
+
+Copyright (C) 2011, 2012 Google Inc.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301, USA.
+
+-}
+
+module Ganeti.Daemon
+ ( DaemonOptions(..)
+ , OptType
+ , defaultOptions
+ , oShowHelp
+ , oShowVer
+ , oNoDaemonize
+ , oNoUserChecks
+ , oDebug
+ , oPort
+ , parseArgs
+ , writePidFile
+ , genericMain
+ ) where
+
+import Control.Monad
+import qualified Data.Version
+import Data.Word
+import System.Console.GetOpt
+import System.Exit
+import System.Environment
+import System.Info
+import System.IO
+import System.Posix.Directory
+import System.Posix.Files
+import System.Posix.IO
+import System.Posix.Process
+import System.Posix.Types
+import Text.Printf
+
+import Ganeti.Logging
+import Ganeti.Runtime
+import Ganeti.BasicTypes
+import Ganeti.HTools.Utils
+import qualified Ganeti.HTools.Version as Version(version)
+import qualified Ganeti.Constants as C
+
+-- * Data types
+
+-- | Command line options structure.
+data DaemonOptions = DaemonOptions
+ { optShowHelp :: Bool -- ^ Just show the help
+ , optShowVer :: Bool -- ^ Just show the program version
+ , optDaemonize :: Bool -- ^ Whether to daemonize or not
+ , optPort :: Maybe Word16 -- ^ Override for the network port
+ , optDebug :: Bool -- ^ Enable debug messages
+ , optNoUserChecks :: Bool -- ^ Ignore user checks
+ }
+
+-- | Default values for the command line options.
+defaultOptions :: DaemonOptions
+defaultOptions = DaemonOptions
+ { optShowHelp = False
+ , optShowVer = False
+ , optDaemonize = True
+ , optPort = Nothing
+ , optDebug = False
+ , optNoUserChecks = False
+ }
+
+-- | Abrreviation for the option type.
+type OptType = OptDescr (DaemonOptions -> Result DaemonOptions)
+
+-- | Helper function for required arguments which need to be converted
+-- as opposed to stored just as string.
+reqWithConversion :: (String -> Result a)
+ -> (a -> DaemonOptions -> Result DaemonOptions)
+ -> String
+ -> ArgDescr (DaemonOptions -> Result DaemonOptions)
+reqWithConversion conversion_fn updater_fn metavar =
+ ReqArg (\string_opt opts -> do
+ parsed_value <- conversion_fn string_opt
+ updater_fn parsed_value opts) metavar
+
+-- * Command line options
+
+oShowHelp :: OptType
+oShowHelp = Option "h" ["help"]
+ (NoArg (\ opts -> Ok opts { optShowHelp = True}))
+ "Show the help message and exit"
+
+oShowVer :: OptType
+oShowVer = Option "V" ["version"]
+ (NoArg (\ opts -> Ok opts { optShowVer = True}))
+ "Show the version of the program and exit"
+
+oNoDaemonize :: OptType
+oNoDaemonize = Option "f" ["foreground"]
+ (NoArg (\ opts -> Ok opts { optDaemonize = False}))
+ "Don't detach from the current terminal"
+
+oDebug :: OptType
+oDebug = Option "d" ["debug"]
+ (NoArg (\ opts -> Ok opts { optDebug = True }))
+ "Enable debug messages"
+
+oNoUserChecks :: OptType
+oNoUserChecks = Option "" ["no-user-checks"]
+ (NoArg (\ opts -> Ok opts { optNoUserChecks = True }))
+ "Ignore user checks"
+
+oPort :: Int -> OptType
+oPort def = Option "p" ["--port"]
+ (reqWithConversion (tryRead "reading port")
+ (\port opts -> Ok opts { optPort = Just port }) "PORT")
+ ("Network port (default: " ++ show def ++ ")")
+
+-- | Usage info.
+usageHelp :: String -> [OptType] -> String
+usageHelp progname =
+ usageInfo (printf "%s %s\nUsage: %s [OPTION...]"
+ progname Version.version progname)
+
+-- | Command line parser, using the 'Options' structure.
+parseOpts :: [String] -- ^ The command line arguments
+ -> String -- ^ The program name
+ -> [OptType] -- ^ The supported command line options
+ -> IO (DaemonOptions, [String]) -- ^ The resulting options
+ -- and leftover arguments
+parseOpts argv progname options =
+ case getOpt Permute options argv of
+ (opt_list, args, []) ->
+ do
+ parsed_opts <-
+ case foldM (flip id) defaultOptions opt_list of
+ Bad msg -> do
+ hPutStrLn stderr "Error while parsing command\
+ \line arguments:"
+ hPutStrLn stderr msg
+ exitWith $ ExitFailure 1
+ Ok val -> return val
+ return (parsed_opts, args)
+ (_, _, errs) -> do
+ hPutStrLn stderr $ "Command line error: " ++ concat errs
+ hPutStrLn stderr $ usageHelp progname options
+ exitWith $ ExitFailure 2
+
+-- | Small wrapper over getArgs and 'parseOpts'.
+parseArgs :: String -> [OptType] -> IO (DaemonOptions, [String])
+parseArgs cmd options = do
+ cmd_args <- getArgs
+ parseOpts cmd_args cmd options
+
+-- * Daemon-related functions
+-- | PID file mode.
+pidFileMode :: FileMode
+pidFileMode = unionFileModes ownerReadMode ownerWriteMode
+
+-- | Writes a PID file and locks it.
+_writePidFile :: FilePath -> IO Fd
+_writePidFile path = do
+ fd <- createFile path pidFileMode
+ setLock fd (WriteLock, AbsoluteSeek, 0, 0)
+ my_pid <- getProcessID
+ _ <- fdWrite fd (show my_pid ++ "\n")
+ return fd
+
+-- | Wrapper over '_writePidFile' that transforms IO exceptions into a
+-- 'Bad' value.
+writePidFile :: FilePath -> IO (Result Fd)
+writePidFile path = do
+ catch (fmap Ok $ _writePidFile path) (return . Bad . show)
+
+-- | Sets up a daemon's environment.
+setupDaemonEnv :: FilePath -> FileMode -> IO ()
+setupDaemonEnv cwd umask = do
+ changeWorkingDirectory cwd
+ _ <- setFileCreationMask umask
+ _ <- createSession
+ return ()
+
+-- | Run an I/O action as a daemon.
+--
+-- WARNING: this only works in single-threaded mode (either using the
+-- single-threaded runtime, or using the multi-threaded one but with
+-- only one OS thread, i.e. -N1).
+--
+-- FIXME: this doesn't support error reporting and the prepfn
+-- functionality.
+daemonize :: IO () -> IO ()
+daemonize action = do
+ -- first fork
+ _ <- forkProcess $ do
+ -- in the child
+ setupDaemonEnv "/" (unionFileModes groupModes otherModes)
+ _ <- forkProcess action
+ exitImmediately ExitSuccess
+ exitImmediately ExitSuccess
+
+-- | Generic daemon startup.
+genericMain :: GanetiDaemon -> [OptType] -> (DaemonOptions -> IO ()) -> IO ()
+genericMain daemon options main = do
+ let progname = daemonName daemon
+ (opts, args) <- parseArgs progname options
+
+ when (optShowHelp opts) $ do
+ putStr $ usageHelp progname options
+ exitWith ExitSuccess
+ when (optShowVer opts) $ do
+ printf "%s %s\ncompiled with %s %s\nrunning on %s %s\n"
+ progname Version.version
+ compilerName (Data.Version.showVersion compilerVersion)
+ os arch :: IO ()
+ exitWith ExitSuccess
+ unless (null args) $ do
+ hPutStrLn stderr "This program doesn't take any arguments"
+ exitWith $ ExitFailure C.exitFailure
+
+ unless (optNoUserChecks opts) $ do
+ runtimeEnts <- getEnts
+ case runtimeEnts of
+ Bad msg -> do
+ hPutStrLn stderr $ "Can't find required user/groups: " ++ msg
+ exitWith $ ExitFailure C.exitFailure
+ Ok ents -> verifyDaemonUser daemon ents
+
+ let processFn = if optDaemonize opts then daemonize else id
+ processFn $ innerMain daemon opts (main opts)
+
+-- | Inner daemon function.
+--
+-- This is executed after daemonization.
+innerMain :: GanetiDaemon -> DaemonOptions -> IO () -> IO ()
+innerMain daemon opts main = do
+ setupLogging (daemonLogFile daemon) (daemonName daemon) (optDebug opts)
+ (not (optDaemonize opts)) False
+ pid_fd <- writePidFile (daemonPidFile daemon)
+ case pid_fd of
+ Bad msg -> do
+ hPutStrLn stderr $ "Cannot write PID file; already locked? Error: " ++
+ msg
+ exitWith $ ExitFailure 1
+ _ -> return ()
+ logNotice "starting"
+ main
projects / ganeti-local / commitdiff