Defer daemonization to Fuse, introduce Fuse::runInBackground() / Fuse::runInForeground()

src/cryfs-cli/Cli.cpp

@@ -268,11 +268,15 @@ namespace cryfs {
           std::cout << "\nMounting filesystem. To unmount, call:\n$ fusermount -u " << options.mountDir() << "\n"
                     << std::endl;
 #endif
-          fuse->run(options.mountDir(), options.fuseOptions());
+            if (options.foreground()) {
+                fuse->runInForeground(options.mountDir(), options.fuseOptions());
+            } else {
+                fuse->runInBackground(options.mountDir(), options.fuseOptions());
+            }
 
-          if (stoppedBecauseOfIntegrityViolation) {
+            if (stoppedBecauseOfIntegrityViolation) {
               throw CryfsException("Integrity violation detected. Unmounting.", ErrorCode::IntegrityViolation);
-          }
+            }
         } catch (const CryfsException &e) {
             throw; // CryfsException is only thrown if setup goes wrong. Throw it through so that we get the correct process exit code.
         } catch (const std::exception &e) {

src/cryfs-cli/program_options/Parser.cpp

@@ -56,9 +56,6 @@ ProgramOptions Parser::parse(const vector<string> &supportedCiphers) const {
         configfile = bf::absolute(vm["config"].as<string>());
     }
     bool foreground = vm.count("foreground");
-    if (foreground) {
-        fuseOptions.push_back(const_cast<char*>("-f"));
-    }
     bool allowFilesystemUpgrade = vm.count("allow-filesystem-upgrade");
     bool allowReplacedFilesystem = vm.count("allow-replaced-filesystem");
     optional<double> unmountAfterIdleMinutes = 0.0;  // first setting to 0 and then to none is somehow needed to silence a GCC warning from -Wmaybe-uninitialized

src/fspp/fuse/Fuse.cpp

@@ -243,7 +243,33 @@ void Fuse::_logUnknownException() {
   LOG(ERR, "Unknown exception thrown");
 }
 
-void Fuse::run(const bf::path &mountdir, const vector<string> &fuseOptions) {
+void Fuse::runInForeground(const bf::path &mountdir, const vector<string> &fuseOptions) {
+  vector<string> realFuseOptions = fuseOptions;
+  if (std::find(realFuseOptions.begin(), realFuseOptions.end(), "-f") == realFuseOptions.end()) {
+    realFuseOptions.push_back("-f");
+  }
+  _run(mountdir, realFuseOptions);
+}
+
+void Fuse::runInBackground(const bf::path &mountdir, const vector<string> &fuseOptions) {
+  vector<string> realFuseOptions = fuseOptions;
+  _removeAndWarnIfExists(&realFuseOptions, "-f");
+  _removeAndWarnIfExists(&realFuseOptions, "-d");
+  _run(mountdir, realFuseOptions);
+}
+
+void Fuse::_removeAndWarnIfExists(vector<string> *fuseOptions, const std::string &option) {
+  auto found = std::find(fuseOptions->begin(), fuseOptions->end(), option);
+  if (found != fuseOptions->end()) {
+    LOG(WARN, "The fuse option {} only works when running in foreground. Removing fuse option.", option);
+    do {
+      fuseOptions->erase(found);
+      found = std::find(fuseOptions->begin(), fuseOptions->end(), option);
+    } while (found != fuseOptions->end());
+  }
+}
+
+void Fuse::_run(const bf::path &mountdir, const vector<string> &fuseOptions) {
   _mountdir = mountdir;
 
   ASSERT(_argv.size() == 0, "Filesystem already started");

src/fspp/fuse/Fuse.h

@@ -24,7 +24,8 @@ public:
   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);
+  void runInBackground(const boost::filesystem::path &mountdir, const std::vector<std::string> &fuseOptions);
+  void runInForeground(const boost::filesystem::path &mountdir, const std::vector<std::string> &fuseOptions);
   bool running() const;
   void stop();
 
@@ -63,6 +64,8 @@ private:
   static void _logException(const std::exception &e);
   static void _logUnknownException();
   static char *_create_c_string(const std::string &str);
+  static void _removeAndWarnIfExists(std::vector<std::string> *fuseOptions, const std::string &option);
+  void _run(const boost::filesystem::path &mountdir, const std::vector<std::string> &fuseOptions);
   static bool _has_option(const std::vector<char *> &vec, const std::string &key);
   static bool _has_entry_with_prefix(const std::string &prefix, const std::vector<char *> &vec);
   std::vector<char *> _build_argv(const boost::filesystem::path &mountdir, const std::vector<std::string> &fuseOptions);

test/fspp/testutils/FuseTest.cpp

@@ -59,7 +59,7 @@ FuseTest::TempTestFS::TempTestFS(shared_ptr<MockFilesystem> fsimpl)
  :_mountDir(),
   _fuse([fsimpl] (Fuse*) {return fsimpl;}, []{}, "fusetest", boost::none), _fuse_thread(&_fuse) {
 
-  _fuse_thread.start(_mountDir.path(), {"-f"});
+  _fuse_thread.start(_mountDir.path(), {});
 }
 
 FuseTest::TempTestFS::~TempTestFS() {

test/fspp/testutils/FuseThread.cpp

@@ -18,7 +18,7 @@ FuseThread::FuseThread(Fuse *fuse)
 
 void FuseThread::start(const bf::path &mountDir, const vector<string> &fuseOptions) {
   _child = thread([this, mountDir, fuseOptions] () {
-    _fuse->run(mountDir, fuseOptions);
+    _fuse->runInForeground(mountDir, fuseOptions);
   });
   //Wait until it is running (busy waiting is simple and doesn't hurt much here)
   while(!_fuse->running()) {}