From 223b1d8fbcc708a08cef347e750b2fa3ceb10bee Mon Sep 17 00:00:00 2001 From: Benjamin Barenblat Date: Wed, 30 Sep 2020 12:42:32 -0400 Subject: xscreensaver-dbus, a bridge between D-Bus and xscreensaver --- .gitignore | 17 ++++ CONTRIBUTING.md | 29 +++++++ LICENSE | 202 ++++++++++++++++++++++++++++++++++++++++++++++ README.md | 9 +++ Setup.hs | 17 ++++ src/Main.hs | 105 ++++++++++++++++++++++++ src/Pool.hs | 55 +++++++++++++ xscreensaver-dbus.cabal | 94 +++++++++++++++++++++ xscreensaver-dbus.service | 38 +++++++++ 9 files changed, 566 insertions(+) create mode 100644 .gitignore create mode 100644 CONTRIBUTING.md create mode 100644 LICENSE create mode 100644 README.md create mode 100644 Setup.hs create mode 100644 src/Main.hs create mode 100644 src/Pool.hs create mode 100644 xscreensaver-dbus.cabal create mode 100644 xscreensaver-dbus.service diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..fa10948 --- /dev/null +++ b/.gitignore @@ -0,0 +1,17 @@ +# Copyright 2020 Google LLC +# +# Licensed under the Apache License, Version 2.0 (the "License"); you may not +# use this file except in compliance with the License. You may obtain a copy of +# the License at +# +# https://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +# License for the specific language governing permissions and limitations under +# the License. + +.ghc.environment.* +cabal.project.local +dist* diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md new file mode 100644 index 0000000..22b241c --- /dev/null +++ b/CONTRIBUTING.md @@ -0,0 +1,29 @@ +# How to Contribute + +We'd love to accept your patches and contributions to this project. There are +just a few small guidelines you need to follow. + +## Contributor License Agreement + +Contributions to this project must be accompanied by a Contributor License +Agreement (CLA). 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We also recommend that a + file or class name and description of purpose be included on the + same "printed page" as the copyright notice for easier + identification within third-party archives. + + Copyright [yyyy] [name of copyright owner] + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. diff --git a/README.md b/README.md new file mode 100644 index 0000000..c80466c --- /dev/null +++ b/README.md @@ -0,0 +1,9 @@ +# xscreensaver-dbus + +xscreensaver-dbus implements the freedesktop.org D-Bus API for screensavers, +translating D-Bus calls into appropriate invocations of xscreensaver-command. +This allows D-Bus-compliant applications to interface with xscreensaver. + +Currently, xscreensaver-dbus only supports the [Idle Inhibition +Service](https://people.freedesktop.org/~hadess/idle-inhibition-spec/) +interface, but adding additional interfaces should be straightforward. diff --git a/Setup.hs b/Setup.hs new file mode 100644 index 0000000..6091805 --- /dev/null +++ b/Setup.hs @@ -0,0 +1,17 @@ +-- Copyright 2020 Google LLC +-- +-- Licensed under the Apache License, Version 2.0 (the "License"); you may not +-- use this file except in compliance with the License. You may obtain a copy of +-- the License at +-- +-- https://www.apache.org/licenses/LICENSE-2.0 +-- +-- Unless required by applicable law or agreed to in writing, software +-- distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +-- WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +-- License for the specific language governing permissions and limitations under +-- the License. + +import Distribution.Simple + +main = defaultMain diff --git a/src/Main.hs b/src/Main.hs new file mode 100644 index 0000000..dddc9ba --- /dev/null +++ b/src/Main.hs @@ -0,0 +1,105 @@ +-- Copyright 2020 Google LLC +-- +-- Licensed under the Apache License, Version 2.0 (the "License"); you may not +-- use this file except in compliance with the License. You may obtain a copy of +-- the License at +-- +-- https://www.apache.org/licenses/LICENSE-2.0 +-- +-- Unless required by applicable law or agreed to in writing, software +-- distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +-- WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +-- License for the specific language governing permissions and limitations under +-- the License. + +{-# LANGUAGE OverloadedStrings #-} +module Main (main) where + +import Control.Concurrent (ThreadId, forkIO, killThread, threadDelay) +import Control.Concurrent.MVar ( MVar, modifyMVar, modifyMVar_, newMVar + , newEmptyMVar, putMVar, readMVar, takeMVar ) +import Control.Exception (assert) +import Control.Monad (forever, unless, void) +import Data.Maybe (fromJust, isJust, isNothing) +import qualified Data.Set as Set +import Data.Word (Word32) +import qualified DBus as D +import qualified DBus.Client as DC +import System.IO (hPutStrLn, stderr) +import System.Posix.Signals ( Handler(Catch), fullSignalSet, installHandler + , sigTERM, sigUSR1) +import qualified System.Process as Process + +import Pool (Pool) +import qualified Pool + +busName = "org.freedesktop.ScreenSaver" :: D.BusName +screensaverObjectPath = "/org/freedesktop/ScreenSaver" :: D.ObjectPath +screensaverInterfaceName = "org.freedesktop.ScreenSaver" :: D.InterfaceName + +wakeupSeconds = 10 :: Int + +type State = (Pool Word32, Maybe ThreadId) + +main :: IO () +main = do + -- Start with 0 as a reserved cookie value. The spec [1] doesn't say anything + -- about allowable cookie values, but Firefox uses the zero cookie value to + -- indicate “no cookie” [2]. Ensure that we never return a zero cookie to a + -- legitimate inhibition request. + -- + -- [1] https://people.freedesktop.org/~hadess/idle-inhibition-spec/index.html + -- [2] https://dxr.mozilla.org/mozilla-central/rev/a58462ad649eb95372a1665480505bdefc2b7531/widget/gtk/WakeLockListener.cpp#71 + state <- newMVar (Pool.withReserved (Set.singleton 0), Nothing) + -- Set up SIGUSR1 to dump state. + void $ installHandler sigUSR1 (Catch (showInfo state)) (Just fullSignalSet) + -- Connect to the bus and start listening. + client <- DC.connectSession + requestNameReply <- DC.requestName client busName [DC.nameDoNotQueue] + unless (requestNameReply == DC.NamePrimaryOwner) $ + error $ "unable to reserve bus name: " ++ show requestNameReply + DC.export client screensaverObjectPath + DC.defaultInterface + { DC.interfaceName = screensaverInterfaceName + , DC.interfaceMethods = + [ DC.autoMethod "Inhibit" (inhibit state) + , DC.autoMethod "UnInhibit" (uninhibit state) ] } + -- Wait for exit. Reference: + -- https://mail.haskell.org/pipermail/haskell-cafe/2010-May/077841.html + shouldExit <- newEmptyMVar + void $ installHandler sigTERM (Catch $ putMVar shouldExit ()) Nothing + takeMVar shouldExit + +inhibit :: MVar State -> String -> String -> IO Word32 +inhibit stateM _appname _reason = + modifyMVar stateM $ \(inhibitions, waker) -> do + let (cookie, inhibitions') = fromJust $ Pool.take inhibitions + waker' <- if Pool.null inhibitions + then assert (isNothing waker) $ + Just <$> forkIO wakerMain + else return waker + return ((inhibitions', waker'), cookie) + +uninhibit :: MVar State -> Word32 -> IO () +uninhibit stateM cookie = modifyMVar_ stateM $ \state@(inhibitions, waker) -> + case Pool.put cookie inhibitions of + Nothing -> return state + Just inhibitions' -> do + waker' <- if Pool.null inhibitions' + then do + assert (isJust waker) (killThread $ fromJust waker) + return Nothing + else return waker + return (inhibitions', waker') + +wakerMain :: IO () +wakerMain = forever $ do + Process.callProcess "xscreensaver-command" ["-deactivate"] + threadDelay $ wakeupSeconds * microsecondsPerSecond + +showInfo :: MVar State -> IO () +showInfo stateM = do + state <- readMVar stateM + hPutStrLn stderr $ show state + +microsecondsPerSecond = 1000 * 1000 :: Int diff --git a/src/Pool.hs b/src/Pool.hs new file mode 100644 index 0000000..8bb40eb --- /dev/null +++ b/src/Pool.hs @@ -0,0 +1,55 @@ +-- Copyright 2020 Google LLC +-- +-- Licensed under the Apache License, Version 2.0 (the "License"); you may not +-- use this file except in compliance with the License. You may obtain a copy of +-- the License at +-- +-- https://www.apache.org/licenses/LICENSE-2.0 +-- +-- Unless required by applicable law or agreed to in writing, software +-- distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +-- WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +-- License for the specific language governing permissions and limitations under +-- the License. + +{-# OPTIONS_GHC -Wno-missing-import-lists #-} +module Pool + ( Pool + , empty, withReserved + , null + , take, put + ) where + +import Prelude hiding (null, take) + +import Control.Monad (guard) +import qualified Data.List as List +import Data.Set (Set) +import qualified Data.Set as Set + +data Pool a = Pool { reserved :: Set a, taken :: Set a } deriving (Eq, Show) + +empty :: Pool a +empty = withReserved Set.empty + +withReserved :: Set a -> Pool a +withReserved xs = Pool { reserved = xs, taken = Set.empty } + +null :: Pool a -> Bool +null p = Set.null (taken p) + +take :: (Bounded a, Enum a, Ord a) => Pool a -> Maybe (a, Pool a) +take p = do + x <- nextAvailable p + return (x, p { taken = Set.insert x (taken p) }) + +nextAvailable :: (Bounded a, Enum a, Ord a) => Pool a -> Maybe a +nextAvailable p = List.find (`Set.notMember` unavailable p) (enumFrom minBound) + +unavailable :: (Ord a) => Pool a -> Set a +unavailable p = reserved p `Set.union` taken p + +put :: Ord a => a -> Pool a -> Maybe (Pool a) +put x p = do + guard $ x `Set.member` taken p + return $ p { taken = Set.delete x (taken p) } diff --git a/xscreensaver-dbus.cabal b/xscreensaver-dbus.cabal new file mode 100644 index 0000000..b92d06f --- /dev/null +++ b/xscreensaver-dbus.cabal @@ -0,0 +1,94 @@ +-- Copyright 2020 Google LLC +-- +-- Licensed under the Apache License, Version 2.0 (the "License"); you may not +-- use this file except in compliance with the License. You may obtain a copy of +-- the License at +-- +-- https://www.apache.org/licenses/LICENSE-2.0 +-- +-- Unless required by applicable law or agreed to in writing, software +-- distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +-- WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +-- License for the specific language governing permissions and limitations under +-- the License. + +cabal-version: >=2.0 +name: xscreensaver-dbus +version: 0.1.0 +synopsis: D-Bus adapter for xscreensaver +description: + xscreensaver-dbus implements the freedesktop.org D-Bus API for screensavers, + translating D-Bus calls into appropriate invocations of xscreensaver-command. + This allows D-Bus-compliant applications to interface with xscreensaver. +copyright: 2020 Google LLC +license: Apache-2.0 +license-file: LICENSE +author: Benjamin Barenblat +maintainer: bbaren@google.com +category: System +build-type: Simple +extra-source-files: CONTRIBUTING.md + , README.md + , xscreensaver-dbus.service + +executable xscreensaver-dbus + hs-source-dirs: src + default-language: Haskell2010 + other-extensions: OverloadedStrings + ghc-options: -Werror + -w + -- Enabled by default + -Wdeprecated-flags -Wwarn=deprecated-flags + -Wdeprecations -Wwarn=deprecations + -Wdodgy-foreign-imports + -Wduplicate-exports + -Wempty-enumerations + -Winline-rule-shadowing + -Wmissing-fields + -Wmissing-methods + -Woverflowed-literals + -Woverlapping-patterns + -Wredundant-constraints + -Wtabs + -Wunrecognised-pragmas -Wwarn=unrecognised-pragmas + -Wunrecognised-warning-flags -Wwarn=unrecognised-warning-flags + -Wunsupported-calling-conventions + -Wunsupported-llvm-version + -Wwarnings-deprecations -Wwarn=warnings-deprecations + -Wwrong-do-bind + -Wsimplifiable-class-constraints + -- Enabled by -W + -Wdodgy-exports + -Wdodgy-imports + -Wincomplete-patterns + -Wunbanged-strict-patterns + -Wunused-binds + -Wunused-foralls + -Wunused-imports + -Wunused-matches + -- Enabled by -Wall + -Wnoncanonical-monad-instances + -Wnoncanonical-monadfail-instances + -Wnoncanonical-monoid-instances + -Wmissing-monadfail-instances + -Wsemigroup + -Whi-shadowing + -Widentities + -Wincomplete-uni-patterns + -Wincomplete-record-updates + -Wmissing-export-lists + -Wmissing-import-lists + -Wmissing-exported-signatures + -Wmissing-pattern-synonym-signatures + -Wname-shadowing + -threaded + -rtsopts=none + -with-rtsopts=-I0 + -with-rtsopts=-V0 + main-is: Main.hs + other-modules: Pool + build-depends: base >=4.9 && <4.12 + , containers ^>=0.5.7.1 + , dbus ^>=1.0.1 + , process >=1.4.2 && <1.7 + , unix ^>=2.7.2 diff --git a/xscreensaver-dbus.service b/xscreensaver-dbus.service new file mode 100644 index 0000000..b710773 --- /dev/null +++ b/xscreensaver-dbus.service @@ -0,0 +1,38 @@ +# Copyright 2020 Google LLC +# +# Licensed under the Apache License, Version 2.0 (the "License"); you may not +# use this file except in compliance with the License. You may obtain a copy of +# the License at +# +# https://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT +# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the +# License for the specific language governing permissions and limitations under +# the License. + +[Unit] +Description=xscreensaver-dbus D-Bus/XScreenSaver adapter + +[Service] +Type=dbus +BusName=org.freedesktop.ScreenSaver +ExecStart=%h/.local/bin/xscreensaver-dbus +NoNewPrivileges=true +KeyringMode=private +ProtectSystem=strict +ProtectHome=true +InaccessiblePaths=-/afs /boot -/lost+found /media /mnt /opt /proc /root /run /srv /sys /var +PrivateTmp=true +ProtectKernelTunables=true +ProtectControlGroups=true +RestrictNamespaces=true +LockPersonality=true +MemoryDenyWriteExecute=true +RestrictRealtime=true +RemoveIPC=true +SystemCallArchitectures=native + +[Install] +WantedBy=default.target -- cgit v1.2.3