Fuse offers an onMounted callback that is called when everything is ready.

src/cryfs-cli/Cli.cpp

@@ -51,8 +51,8 @@ using std::string;
 using std::endl;
 using std::shared_ptr;
 using std::make_shared;
+using std::make_unique;
 using std::function;
-using std::make_shared;
 using boost::optional;
 using boost::none;
 using boost::chrono::minutes;
@@ -219,7 +219,7 @@ namespace cryfs {
                                cipher, blocksizeBytes, missingBlockIsIntegrityViolation).loadOrCreate(std::move(configFilePath), allowFilesystemUpgrade, allowReplacedFilesystem);
     }
 
-    void Cli::_runFilesystem(const ProgramOptions &options) {
+    void Cli::_runFilesystem(const ProgramOptions &options, std::function<void()> onMounted) {
         try {
             LocalStateDir localStateDir(Environment::localStateDir());
             auto blockStore = make_unique_ref<OnDiskBlockStore2>(options.baseDir());
@@ -229,11 +229,11 @@ namespace cryfs {
                                                                                  options.allowIntegrityViolations(), missingBlockIsIntegrityViolation));
             _sanityCheckFilesystem(_device->get());
 
-            auto initFilesystem = [this, &options] (fspp::fuse::Fuse *fuse){
+            auto initFilesystem = [&] (fspp::fuse::Fuse *fs){
                 ASSERT(_device != none, "File system not ready to be initialized. Was it already initialized before?");
 
                 //TODO Test auto unmounting after idle timeout
-                _idleUnmounter = _createIdleCallback(options.unmountAfterIdleMinutes(), [fuse] {fuse->stop();});
+                _idleUnmounter = _createIdleCallback(options.unmountAfterIdleMinutes(), [fs] {fs->stop();});
                 if (_idleUnmounter != none) {
                     (*_device)->onFsAction(std::bind(&CallAfterTimeout::resetTimer, _idleUnmounter->get()));
                 }
@@ -241,7 +241,7 @@ namespace cryfs {
                 return make_shared<fspp::FilesystemImpl>(std::move(*_device));
             };
 
-            auto fuse = make_unique_ref<fspp::fuse::Fuse>(initFilesystem, "cryfs", "cryfs@" + options.baseDir().string());
+            auto fuse = make_unique<fspp::fuse::Fuse>(initFilesystem, std::move(onMounted), "cryfs", "cryfs@" + options.baseDir().string());
 
             _initLogfile(options);
 
@@ -369,14 +369,14 @@ namespace cryfs {
         return false;
     }
 
-    int Cli::main(int argc, const char *argv[], unique_ref<HttpClient> httpClient) {
+    int Cli::main(int argc, const char *argv[], unique_ref<HttpClient> httpClient, std::function<void()> onMounted) {
         cpputils::showBacktraceOnCrash();
 
         try {
             _showVersion(std::move(httpClient));
             ProgramOptions options = program_options::Parser(argc, argv).parse(CryCiphers::supportedCipherNames());
             _sanityChecks(options);
-            _runFilesystem(options);
+            _runFilesystem(options, std::move(onMounted));
         } catch (const CryfsException &e) {
             if (e.errorCode() != ErrorCode::Success) {
               std::cerr << "Error: " << e.what() << std::endl;

src/cryfs-cli/Cli.h

@@ -18,11 +18,11 @@ namespace cryfs {
     class Cli final {
     public:
         Cli(cpputils::RandomGenerator &keyGenerator, const cpputils::SCryptSettings& scryptSettings, std::shared_ptr<cpputils::Console> console);
-        int main(int argc, const char *argv[], cpputils::unique_ref<cpputils::HttpClient> httpClient);
+        int main(int argc, const char *argv[], cpputils::unique_ref<cpputils::HttpClient> httpClient, std::function<void()> onMounted);
 
     private:
         void _checkForUpdates(cpputils::unique_ref<cpputils::HttpClient> httpClient);
-        void _runFilesystem(const program_options::ProgramOptions &options);
+        void _runFilesystem(const program_options::ProgramOptions &options, std::function<void()> onMounted);
         CryConfigLoader::ConfigLoadResult _loadOrCreateConfig(const program_options::ProgramOptions &options, const LocalStateDir& localStateDir);
         void _checkConfigIntegrity(const boost::filesystem::path& basedir, const LocalStateDir& localStateDir, const CryConfigFile& config, bool allowReplacedFilesystem);
         boost::optional<CryConfigLoader::ConfigLoadResult> _loadOrCreateConfigFile(boost::filesystem::path configFilePath, LocalStateDir localStateDir, const boost::optional<std::string> &cipher, const boost::optional<uint32_t> &blocksizeBytes, bool allowFilesystemUpgrade, const boost::optional<bool> &missingBlockIsIntegrityViolation, bool allowReplacedFilesystem);

src/cryfs-cli/main.cpp

@@ -26,7 +26,7 @@ int main(int argc, const char *argv[]) {
 		    auto httpClient = make_unique_ref<cpputils::CurlHttpClient>();
 #endif
         return Cli(keyGenerator, SCrypt::DefaultSettings, make_shared<IOStreamConsole>())
-            .main(argc, argv, std::move(httpClient));
+            .main(argc, argv, std::move(httpClient), []{});
     } catch (const CryfsException &e) {
         if (e.errorCode() != ErrorCode::Success) {
             std::cerr << "Error: " << e.what() << std::endl;

src/fspp/fuse/Fuse.cpp

@@ -229,8 +229,10 @@ Fuse::~Fuse() {
   _argv.clear();
 }
 
-Fuse::Fuse(std::function<shared_ptr<Filesystem> (Fuse *fuse)> init, std::string fstype, boost::optional<std::string> fsname)
+Fuse::Fuse(std::function<shared_ptr<Filesystem> (Fuse *fuse)> init, std::function<void()> onMounted, std::string fstype, boost::optional<std::string> fsname)
-  :_init(std::move(init)), _fs(make_shared<InvalidFilesystem>()), _mountdir(), _running(false), _fstype(std::move(fstype)), _fsname(std::move(fsname)) {
+  :_init(std::move(init)), _onMounted(std::move(onMounted)), _fs(make_shared<InvalidFilesystem>()), _mountdir(), _running(false), _fstype(std::move(fstype)), _fsname(std::move(fsname)) {
+  ASSERT(static_cast<bool>(_init), "Invalid init given");
+  ASSERT(static_cast<bool>(_onMounted), "Invalid onMounted given");
 }
 
 void Fuse::_logException(const std::exception &e) {
@@ -866,6 +868,7 @@ void Fuse::init(fuse_conn_info *conn) {
   LOG(INFO, "Filesystem started.");
 
   _running = true;
+  _onMounted();
 
 #ifdef FSPP_LOG
   cpputils::logging::setLevel(DEBUG);

src/fspp/fuse/Fuse.h

@@ -21,7 +21,7 @@ class Filesystem;
 
 class Fuse final {
 public:
-  explicit Fuse(std::function<std::shared_ptr<Filesystem> (Fuse *fuse)> init, std::string fstype, boost::optional<std::string> fsname);
+  explicit Fuse(std::function<std::shared_ptr<Filesystem> (Fuse *fuse)> init, std::function<void()> onMounted, std::string fstype, boost::optional<std::string> fsname);
   ~Fuse();
 
   void run(const boost::filesystem::path &mountdir, const std::vector<std::string> &fuseOptions);
@@ -69,6 +69,7 @@ private:
   void _add_fuse_option_if_not_exists(std::vector<char *> *argv, const std::string &key, const std::string &value);
 
   std::function<std::shared_ptr<Filesystem> (Fuse *fuse)> _init;
+  std::function<void()> _onMounted;
   std::shared_ptr<Filesystem> _fs;
   boost::filesystem::path _mountdir;
   std::vector<char*> _argv;

test/cryfs-cli/testutils/CliTest.h

@@ -16,6 +16,7 @@
 #include <cpp-utils/logging/logging.h>
 #include <cpp-utils/process/subprocess.h>
 #include <cpp-utils/network/FakeHttpClient.h>
+#include <cpp-utils/lock/ConditionBarrier.h>
 #include "../../cryfs/testutils/MockConsole.h"
 #include "../../cryfs/testutils/TestWithFakeHomeDirectory.h"
 #include <cryfs/ErrorCodes.h>
@@ -41,7 +42,7 @@ public:
         return std::move(httpClient);
     }
 
-    int run(const std::vector<std::string>& args) {
+    int run(const std::vector<std::string>& args, std::function<void()> onMounted) {
         std::vector<const char*> _args;
         _args.reserve(args.size() + 1);
             _args.emplace_back("cryfs");
@@ -52,7 +53,7 @@ public:
         ON_CALL(*console, askPassword(testing::StrEq("Password: "))).WillByDefault(testing::Return("pass"));
         ON_CALL(*console, askPassword(testing::StrEq("Confirm Password: "))).WillByDefault(testing::Return("pass"));
         // Run Cryfs
-        return cryfs::Cli(keyGenerator, cpputils::SCrypt::TestSettings, console).main(_args.size(), _args.data(), _httpClient());
+        return cryfs::Cli(keyGenerator, cpputils::SCrypt::TestSettings, console).main(_args.size(), _args.data(), _httpClient(), std::move(onMounted));
     }
 
     void EXPECT_EXIT_WITH_HELP_MESSAGE(const std::vector<std::string>& args, const std::string &message, cryfs::ErrorCode errorCode) {
@@ -60,7 +61,7 @@ public:
     }
 
     void EXPECT_RUN_ERROR(const std::vector<std::string>& args, const std::string& message, cryfs::ErrorCode errorCode) {
-        FilesystemOutput filesystem_output = _run_filesystem(args, boost::none);
+        FilesystemOutput filesystem_output = _run_filesystem(args, boost::none, []{});
 
         EXPECT_EQ(exitCode(errorCode), filesystem_output.exit_code);
         EXPECT_TRUE(std::regex_search(filesystem_output.stderr_, std::regex(message)));
@@ -70,7 +71,7 @@ public:
         //TODO Make this work when run in background
         ASSERT(std::find(args.begin(), args.end(), string("-f")) != args.end(), "Currently only works if run in foreground");
 
-		FilesystemOutput filesystem_output = _run_filesystem(args, mountDir);
+        FilesystemOutput filesystem_output = _run_filesystem(args, mountDir, []{});
 
         EXPECT_EQ(0, filesystem_output.exit_code);
         EXPECT_TRUE(std::regex_search(filesystem_output.stdout_, std::regex("Mounting filesystem")));
@@ -82,44 +83,64 @@ public:
         std::string stderr_;
     };
 
-    FilesystemOutput _run_filesystem(const std::vector<std::string>& args, const boost::optional<boost::filesystem::path>& mountDirForUnmounting) {
+    static void _unmount(const boost::filesystem::path &mountDir) {
-		testing::internal::CaptureStdout();
-		testing::internal::CaptureStderr();
-        std::future<int> exit_code = std::async(std::launch::async, [this, &args] {
-            return run(args);
-        });
-
-        if (mountDirForUnmounting.is_initialized()) {
-            boost::filesystem::path mountDir = *mountDirForUnmounting;
-            std::future<bool> unmount_success = std::async(std::launch::async, [&mountDir] {
         int returncode = -1;
-                while (returncode != 0) {
 #if defined(__APPLE__)
         returncode = cpputils::Subprocess::call(std::string("umount ") + mountDir.string().c_str() + " 2>/dev/null").exitcode;
 #elif defined(_MSC_VER)
-                    // Somehow this sleeping is needed to not deadlock. Race condition in mounting/unmounting?
-				std::this_thread::sleep_for(std::chrono::milliseconds(50));
         std::wstring mountDir_ = std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>>().from_bytes(mountDir.string());
         BOOL success = DokanRemoveMountPoint(mountDir_.c_str());
         returncode = success ? 0 : -1;
 #else
-                    returncode = cpputils::Subprocess::call(std::string("fusermount -u ") + mountDir.string().c_str() + " 2>/dev/null").exitcode;
+        returncode = cpputils::Subprocess::call(
+        std::string("fusermount -u ") + mountDir.string().c_str() + " 2>/dev/null").exitcode;
 #endif
+        ASSERT(returncode == 0, "Unmount failed");
+    }
+
+    FilesystemOutput _run_filesystem(const std::vector<std::string>& args, boost::optional<boost::filesystem::path> mountDirForUnmounting, std::function<void()> onMounted) {
+        testing::internal::CaptureStdout();
+        testing::internal::CaptureStderr();
+
+        bool exited = false;
+        cpputils::ConditionBarrier isMountedOrFailedBarrier;
+
+        std::future<int> exit_code = std::async(std::launch::async, [&] {
+            int exit_code = run(args, [&] { isMountedOrFailedBarrier.release(); });
+            // just in case it fails, we also want to release the barrier.
+            // if it succeeds, this will release it a second time, which doesn't hurt.
+            exited = true;
+            isMountedOrFailedBarrier.release();
+            return exit_code;
+        });
+
+        std::future<bool> on_mounted_success = std::async(std::launch::async, [&] {
+            isMountedOrFailedBarrier.wait();
+            if (exited) {
+              // file system already exited on its own, this indicates an error. It should have stayed mounted.
+              // while the exit_code from run() will signal an error in this case, we didn't encounter another
+              // error in the onMounted future, so return true here.
+              return true;
+            }
+            // now we know the filesystem stayed online, so we can call the onMounted callback
+            onMounted();
+            // and unmount it afterwards
+            if (mountDirForUnmounting.is_initialized()) {
+              _unmount(*mountDirForUnmounting);
             }
             return true;
         });
 
-            if(std::future_status::ready != unmount_success.wait_for(std::chrono::seconds(10))) {
+        if(std::future_status::ready != on_mounted_success.wait_for(std::chrono::seconds(10))) {
             testing::internal::GetCapturedStdout(); // stop capturing stdout
             testing::internal::GetCapturedStderr(); // stop capturing stderr
 
-				std::cerr << "Unmount thread didn't finish";
+            std::cerr << "onMounted thread (e.g. used for unmount) didn't finish";
             // The std::future destructor of a future created with std::async blocks until the future is ready.
             // so, instead of causing a deadlock, rather abort
             exit(EXIT_FAILURE);
         }
-            EXPECT_TRUE(unmount_success.get()); // this also re-throws any potential exceptions
+        EXPECT_TRUE(on_mounted_success.get()); // this also re-throws any potential exceptions
-        }
 
         if(std::future_status::ready != exit_code.wait_for(std::chrono::seconds(10))) {
             testing::internal::GetCapturedStdout(); // stop capturing stdout

test/fspp/testutils/FuseTest.cpp

@@ -57,7 +57,7 @@ unique_ref<FuseTest::TempTestFS> FuseTest::TestFS() {
 
 FuseTest::TempTestFS::TempTestFS(shared_ptr<MockFilesystem> fsimpl)
  :_mountDir(),
-  _fuse([fsimpl] (Fuse*) {return fsimpl;}, "fusetest", boost::none), _fuse_thread(&_fuse) {
+  _fuse([fsimpl] (Fuse*) {return fsimpl;}, []{}, "fusetest", boost::none), _fuse_thread(&_fuse) {
 
   _fuse_thread.start(_mountDir.path(), {"-f"});
 }