--unmount-idle x automatically unmounts the filesystem after x minutes without a filesystem operation.

ChangeLog.txt

@@ -11,3 +11,4 @@ Version 0.8.1
 * Allow --cipher=xxx to specify cipher on command line. If cryfs is creating a new filesystem, it will use this cipher. If it is opening an existing filesystem, it will check whether this is the cipher used by it.
 * --show-ciphers shows a list of all supported ciphers
 * --extpass allows using an external program for password input
+* --unmount-idle x automatically unmounts the filesystem after x minutes without a filesystem operation.

src/cli/CallAfterTimeout.h

@@ -21,6 +21,8 @@ namespace cryfs {
         boost::chrono::time_point<boost::chrono::steady_clock> _start;
         cpputils::LoopThread _checkTimeoutThread;
         std::mutex _mutex;
+
+        DISALLOW_COPY_AND_ASSIGN(CallAfterTimeout);
     };
 
     inline CallAfterTimeout::CallAfterTimeout(boost::chrono::milliseconds timeout, std::function<void()> callback)

src/cli/Cli.cpp

@@ -48,7 +48,15 @@ using std::endl;
 using std::vector;
 using std::shared_ptr;
 using std::make_shared;
+using std::unique_ptr;
+using std::make_unique;
+using std::function;
+using boost::optional;
 using boost::none;
+using boost::chrono::duration;
+using boost::chrono::duration_cast;
+using boost::chrono::minutes;
+using boost::chrono::milliseconds;
 
 //TODO Support files > 4GB
 //TODO Improve parallelity.
@@ -148,6 +156,13 @@ namespace cryfs {
 
             _initLogfile(options);
 
+            //TODO Test auto unmounting after idle timeout
+            //TODO This can fail due to a race condition if the filesystem isn't started yet (e.g. passing --unmount-idle 0").
+            auto idleUnmounter = _createIdleCallback(options.unmountAfterIdleMinutes(), [&fuse] {fuse.stop();});
+            if (idleUnmounter != none) {
+                device.onFsAction(std::bind(&CallAfterTimeout::resetTimer, idleUnmounter->get()));
+            }
+
             std::cout << "\nMounting filesystem. To unmount, call:\n$ fusermount -u " << options.mountDir() << "\n" << std::endl;
 
             vector<char *> fuseOptions = options.fuseOptions();
@@ -159,6 +174,14 @@ namespace cryfs {
         }
     }
 
+    optional<unique_ref<CallAfterTimeout>> Cli::_createIdleCallback(optional<double> minutes, function<void()> callback) {
+        if (minutes == none) {
+            return none;
+        }
+        uint64_t millis = std::round(60000 * (*minutes));
+        return make_unique_ref<CallAfterTimeout>(milliseconds(millis), callback);
+    }
+
     void Cli::_initLogfile(const ProgramOptions &options) {
         spdlog::drop("cryfs");
         //TODO Test that --logfile parameter works. Should be: file if specified, otherwise stderr if foreground, else syslog.

src/cli/Cli.h

@@ -7,6 +7,7 @@
 #include <boost/filesystem/path.hpp>
 #include <messmer/cpp-utils/tempfile/TempFile.h>
 #include <messmer/cpp-utils/random/RandomGenerator.h>
+#include "CallAfterTimeout.h"
 
 namespace cryfs {
     class Cli final {
@@ -29,6 +30,7 @@ namespace cryfs {
         void _checkDirAccessible(const boost::filesystem::path &dir, const std::string &name);
         std::shared_ptr<cpputils::TempFile> _checkDirWriteable(const boost::filesystem::path &dir, const std::string &name);
         void _checkDirReadable(const boost::filesystem::path &dir, std::shared_ptr<cpputils::TempFile> tempfile, const std::string &name);
+        boost::optional<cpputils::unique_ref<CallAfterTimeout>> _createIdleCallback(boost::optional<double> minutes, std::function<void()> callback);
 
         cpputils::RandomGenerator &_keyGenerator;
         cpputils::SCryptSettings _scryptSettings;

src/cli/program_options/Parser.cpp

@@ -39,9 +39,9 @@ ProgramOptions Parser::parse(const vector<string> &supportedCiphers) const {
     if (foreground) {
         options.second.push_back(const_cast<char*>("-f"));
     }
-    optional<unsigned int> unmountAfterIdleMinutes = none;
+    optional<double> unmountAfterIdleMinutes = none;
     if (vm.count("unmount-idle")) {
-        unmountAfterIdleMinutes = vm["unmount-idle"].as<unsigned int>();
+        unmountAfterIdleMinutes = vm["unmount-idle"].as<double>();
     }
     optional<string> logfile = none;
     if (vm.count("logfile")) {
@@ -104,7 +104,7 @@ void Parser::_addAllowedOptions(po::options_description *desc) {
             ("foreground,f", "Run CryFS in foreground.")
             ("cipher", po::value<string>(), "Cipher to use for encryption. See possible values by calling cryfs with --show-ciphers")
             ("show-ciphers", "Show list of supported ciphers.")
-            ("unmount-idle", po::value<unsigned int>(), "Automatically unmount after specified number of idle minutes.")
+            ("unmount-idle", po::value<double>(), "Automatically unmount after specified number of idle minutes.")
             ("extpass", po::value<string>(), "External program to use for password input")
             ("logfile", po::value<string>(), "Specify the file to write log messages to. If this is not specified, log messages will go to stdout, or syslog if CryFS is running in the background.")
             ;

src/cli/program_options/ProgramOptions.cpp

@@ -8,7 +8,7 @@ using std::vector;
 using boost::optional;
 
 ProgramOptions::ProgramOptions(const string &baseDir, const string &mountDir, const optional<string> &configFile,
-                               bool foreground, const optional<unsigned int> &unmountAfterIdleMinutes,
+                               bool foreground, const optional<double> &unmountAfterIdleMinutes,
                                const optional<string> &logFile, const optional<string> &cipher,
                                const optional<string> &extPass, const vector<char*> &fuseOptions)
     :_baseDir(baseDir), _mountDir(new char[mountDir.size()+1]), _configFile(configFile), _foreground(foreground),
@@ -50,7 +50,7 @@ bool ProgramOptions::foreground() const {
     return _foreground;
 }
 
-const optional<unsigned int> &ProgramOptions::unmountAfterIdleMinutes() const {
+const optional<double> &ProgramOptions::unmountAfterIdleMinutes() const {
     return _unmountAfterIdleMinutes;
 }
 

src/cli/program_options/ProgramOptions.h

@@ -12,7 +12,7 @@ namespace cryfs {
         class ProgramOptions final {
         public:
             ProgramOptions(const std::string &baseDir, const std::string &mountDir, const boost::optional<std::string> &configFile,
-                           bool foreground, const boost::optional<unsigned int> &unmountAfterIdleMinutes,
+                           bool foreground, const boost::optional<double> &unmountAfterIdleMinutes,
                            const boost::optional<std::string> &logFile, const boost::optional<std::string> &cipher,
                            const boost::optional<std::string> &extPass, const std::vector<char *> &fuseOptions);
             ProgramOptions(ProgramOptions &&rhs);
@@ -23,7 +23,7 @@ namespace cryfs {
             const boost::optional<std::string> &configFile() const;
             bool foreground() const;
             const boost::optional<std::string> &cipher() const;
-            const boost::optional<unsigned int> &unmountAfterIdleMinutes() const;
+            const boost::optional<double> &unmountAfterIdleMinutes() const;
             const boost::optional<std::string> &logFile() const;
             const boost::optional<std::string> &extPass() const;
             const std::vector<char *> &fuseOptions() const;
@@ -34,7 +34,7 @@ namespace cryfs {
             boost::optional<std::string> _configFile;
             bool _foreground;
             boost::optional<std::string> _cipher;
-            boost::optional<unsigned int> _unmountAfterIdleMinutes;
+            boost::optional<double> _unmountAfterIdleMinutes;
             boost::optional<std::string> _logFile;
             boost::optional<std::string> _extPass;
             std::vector<char *> _fuseOptions;

src/filesystem/CryDevice.cpp

@@ -57,7 +57,8 @@ CryDevice::CryDevice(CryConfigFile configFile, unique_ref<BlockStore> blockStore
               ), BLOCKSIZE_BYTES)))
         )
       ),
-  _rootKey(GetOrCreateRootKey(&configFile)) {
+  _rootKey(GetOrCreateRootKey(&configFile)),
+  _onFsAction() {
 }
 
 Key CryDevice::CreateRootBlobAndReturnKey() {
@@ -69,6 +70,8 @@ Key CryDevice::CreateRootBlobAndReturnKey() {
 optional<unique_ref<fspp::Node>> CryDevice::Load(const bf::path &path) {
   ASSERT(path.is_absolute(), "Non absolute path given");
 
+  callFsActionCallbacks();
+
   if (path.parent_path().empty()) {
     //We are asked to load the root directory '/'.
     return optional<unique_ref<fspp::Node>>(make_unique_ref<CryDir>(this, none, _rootKey));
@@ -121,6 +124,7 @@ unique_ref<FsBlobRef> CryDevice::LoadBlob(const bf::path &path) {
 }
 
 void CryDevice::statfs(const bf::path &path, struct statvfs *fsstat) {
+  callFsActionCallbacks();
   throw FuseErrnoException(ENOTSUP);
 }
 
@@ -165,4 +169,14 @@ cpputils::unique_ref<blockstore::BlockStore> CryDevice::CreateEncryptedBlockStor
   return CryCiphers::find(config.Cipher()).createEncryptedBlockstore(std::move(baseBlockStore), config.EncryptionKey());
 }
 
+void CryDevice::onFsAction(std::function<void()> callback) {
+  _onFsAction.push_back(callback);
+}
+
+void CryDevice::callFsActionCallbacks() const {
+  for (const auto &callback : _onFsAction) {
+    callback();
+  }
+}
+
 }

src/filesystem/CryDevice.h

@@ -31,14 +31,18 @@ public:
   cpputils::unique_ref<parallelaccessfsblobstore::DirBlobRef> LoadDirBlob(const boost::filesystem::path &path);
   void RemoveBlob(const blockstore::Key &key);
 
+  void onFsAction(std::function<void()> callback);
+
   boost::optional<cpputils::unique_ref<fspp::Node>> Load(const boost::filesystem::path &path) override;
 
+  void callFsActionCallbacks() const;
 
 private:
 
   cpputils::unique_ref<parallelaccessfsblobstore::ParallelAccessFsBlobStore> _fsBlobStore;
 
   blockstore::Key _rootKey;
+  std::vector<std::function<void()>> _onFsAction;
 
   blockstore::Key GetOrCreateRootKey(CryConfigFile *config);
   blockstore::Key CreateRootBlobAndReturnKey();

src/filesystem/CryDir.cpp

@@ -37,12 +37,14 @@ CryDir::~CryDir() {
 }
 
 unique_ref<fspp::OpenFile> CryDir::createAndOpenFile(const string &name, mode_t mode, uid_t uid, gid_t gid) {
+  device()->callFsActionCallbacks();
   auto child = device()->CreateFileBlob();
   LoadBlob()->AddChildFile(name, child->key(), mode, uid, gid);
-  return make_unique_ref<CryOpenFile>(std::move(child));
+  return make_unique_ref<CryOpenFile>(device(), std::move(child));
 }
 
 void CryDir::createDir(const string &name, mode_t mode, uid_t uid, gid_t gid) {
+  device()->callFsActionCallbacks();
   auto blob = LoadBlob();
   auto child = device()->CreateDirBlob();
   blob->AddChildDir(name, child->key(), mode, uid, gid);
@@ -56,6 +58,7 @@ unique_ref<DirBlobRef> CryDir::LoadBlob() const {
 }
 
 unique_ref<vector<fspp::Dir::Entry>> CryDir::children() const {
+  device()->callFsActionCallbacks();
   auto children = make_unique_ref<vector<fspp::Dir::Entry>>();
   children->push_back(fspp::Dir::Entry(fspp::Dir::EntryType::DIR, "."));
   children->push_back(fspp::Dir::Entry(fspp::Dir::EntryType::DIR, ".."));
@@ -65,10 +68,12 @@ unique_ref<vector<fspp::Dir::Entry>> CryDir::children() const {
 }
 
 fspp::Dir::EntryType CryDir::getType() const {
+  device()->callFsActionCallbacks();
   return fspp::Dir::EntryType::DIR;
 }
 
 void CryDir::createSymlink(const string &name, const bf::path &target, uid_t uid, gid_t gid) {
+  device()->callFsActionCallbacks();
   auto blob = LoadBlob();
   auto child = device()->CreateSymlinkBlob(target);
   blob->AddChildSymlink(name, child->key(), uid, gid);

src/filesystem/CryFile.cpp

@@ -35,16 +35,19 @@ unique_ref<parallelaccessfsblobstore::FileBlobRef> CryFile::LoadBlob() const {
 }
 
 unique_ref<fspp::OpenFile> CryFile::open(int flags) const {
+  device()->callFsActionCallbacks();
   auto blob = LoadBlob();
-  return make_unique_ref<CryOpenFile>(std::move(blob));
+  return make_unique_ref<CryOpenFile>(device(), std::move(blob));
 }
 
 void CryFile::truncate(off_t size) const {
+  device()->callFsActionCallbacks();
   auto blob = LoadBlob();
   blob->resize(size);
 }
 
 fspp::Dir::EntryType CryFile::getType() const {
+  device()->callFsActionCallbacks();
   return fspp::Dir::EntryType::FILE;
 }
 

src/filesystem/CryNode.cpp

@@ -35,12 +35,14 @@ CryNode::~CryNode() {
 }
 
 void CryNode::access(int mask) const {
+  device()->callFsActionCallbacks();
   //TODO
   return;
   throw FuseErrnoException(ENOTSUP);
 }
 
 void CryNode::rename(const bf::path &to) {
+  device()->callFsActionCallbacks();
   if (_parent == none) {
     //We are the root direcory.
     //TODO What should we do?
@@ -59,11 +61,13 @@ void CryNode::rename(const bf::path &to) {
 }
 
 void CryNode::utimens(const timespec times[2]) {
+  device()->callFsActionCallbacks();
   //TODO
   throw FuseErrnoException(ENOTSUP);
 }
 
 void CryNode::remove() {
+  device()->callFsActionCallbacks();
   //TODO Instead of all these if-else and having _parent being an optional, we could also introduce a CryRootDir which inherits from fspp::Dir.
   if (_parent == none) {
     //We are the root direcory.
@@ -87,6 +91,7 @@ unique_ref<FsBlobRef> CryNode::LoadBlob() const {
 }
 
 void CryNode::stat(struct ::stat *result) const {
+  device()->callFsActionCallbacks();
   if(_parent == none) {
     //We are the root directory.
 	//TODO What should we do?
@@ -97,6 +102,7 @@ void CryNode::stat(struct ::stat *result) const {
 }
 
 void CryNode::chmod(mode_t mode) {
+  device()->callFsActionCallbacks();
   if (_parent == none) {
     //We are the root direcory.
 	//TODO What should we do?
@@ -106,6 +112,7 @@ void CryNode::chmod(mode_t mode) {
 }
 
 void CryNode::chown(uid_t uid, gid_t gid) {
+  device()->callFsActionCallbacks();
   if (_parent == none) {
 	//We are the root direcory.
 	//TODO What should we do?

src/filesystem/CryOpenFile.cpp

@@ -17,8 +17,8 @@ using fspp::fuse::FuseErrnoException;
 
 namespace cryfs {
 
-CryOpenFile::CryOpenFile(unique_ref<FileBlobRef> fileBlob)
-: _fileBlob(std::move(fileBlob)) {
+CryOpenFile::CryOpenFile(const CryDevice *device, unique_ref<FileBlobRef> fileBlob)
+: _device(device), _fileBlob(std::move(fileBlob)) {
 }
 
 CryOpenFile::~CryOpenFile() {
@@ -26,32 +26,39 @@ CryOpenFile::~CryOpenFile() {
 }
 
 void CryOpenFile::flush() {
+  _device->callFsActionCallbacks();
   _fileBlob->flush();
 }
 
 void CryOpenFile::stat(struct ::stat *result) const {
+  _device->callFsActionCallbacks();
   result->st_mode = S_IFREG | S_IRUSR | S_IXUSR | S_IWUSR;
   result->st_size = _fileBlob->size();
   return;
 }
 
 void CryOpenFile::truncate(off_t size) const {
+  _device->callFsActionCallbacks();
   _fileBlob->resize(size);
 }
 
 ssize_t CryOpenFile::read(void *buf, size_t count, off_t offset) const {
+  _device->callFsActionCallbacks();
   return _fileBlob->read(buf, offset, count);
 }
 
 void CryOpenFile::write(const void *buf, size_t count, off_t offset) {
+  _device->callFsActionCallbacks();
   _fileBlob->write(buf, offset, count);
 }
 
 void CryOpenFile::fsync() {
+  _device->callFsActionCallbacks();
   //throw FuseErrnoException(ENOTSUP);
 }
 
 void CryOpenFile::fdatasync() {
+  _device->callFsActionCallbacks();
   //throw FuseErrnoException(ENOTSUP);
 }
 

src/filesystem/CryOpenFile.h

@@ -10,7 +10,7 @@ class CryDevice;
 
 class CryOpenFile: public fspp::OpenFile {
 public:
-  explicit CryOpenFile(cpputils::unique_ref<parallelaccessfsblobstore::FileBlobRef> fileBlob);
+  explicit CryOpenFile(const CryDevice *device, cpputils::unique_ref<parallelaccessfsblobstore::FileBlobRef> fileBlob);
   virtual ~CryOpenFile();
 
   void stat(struct ::stat *result) const override;
@@ -22,6 +22,7 @@ public:
   void fdatasync() override;
 
 private:
+  const CryDevice *_device;
   cpputils::unique_ref<parallelaccessfsblobstore::FileBlobRef> _fileBlob;
 
   DISALLOW_COPY_AND_ASSIGN(CryOpenFile);

src/filesystem/CrySymlink.cpp

@@ -40,10 +40,12 @@ unique_ref<SymlinkBlobRef> CrySymlink::LoadBlob() const {
 }
 
 fspp::Dir::EntryType CrySymlink::getType() const {
+  device()->callFsActionCallbacks();
   return fspp::Dir::EntryType::SYMLINK;
 }
 
 bf::path CrySymlink::target() const {
+  device()->callFsActionCallbacks();
   auto blob = LoadBlob();
   return blob->target();
 }

test/cli/program_options/ParserTest.cpp

@@ -81,6 +81,11 @@ TEST_F(ProgramOptionsParserTest, UnmountAfterIdleMinutesGiven) {
     EXPECT_EQ(10, options.unmountAfterIdleMinutes().value());
 }
 
+TEST_F(ProgramOptionsParserTest, UnmountAfterIdleMinutesGiven_Float) {
+    ProgramOptions options = parse({"./myExecutable", "/home/user/baseDir", "--unmount-idle", "0.5", "/home/user/mountDir"});
+    EXPECT_EQ(0.5, options.unmountAfterIdleMinutes().value());
+}
+
 TEST_F(ProgramOptionsParserTest, InvalidCipher) {
     EXPECT_DEATH(
         parse({"./myExecutable", "/home/user/baseDir", "--cipher", "invalid-cipher", "/home/user/mountDir"}),