GIOLister: ignore system mounts as defined by GIO

Strawberry has some heuristics to exclude things
like the root mount, /boot, tmpfs, etc. from the devices list.

However, it's somewhat incomplete. GIO (GLib component)
has more complete definition of "internal system mounts"
that should not be presented to the user.

Additionally, don't try to query filesystems free/total size
if it's internal, as that triggers automounting for autofs
filesystems (#410).

CMakeLists.txt

@@ -117,6 +117,9 @@ endif()
 pkg_check_modules(GLIB REQUIRED glib-2.0)
 pkg_check_modules(GOBJECT REQUIRED gobject-2.0)
 pkg_check_modules(GIO REQUIRED gio-2.0)
+if(UNIX)
+  pkg_check_modules(GIO_UNIX gio-unix-2.0)
+endif()
 pkg_check_modules(LIBCDIO libcdio)
 pkg_check_modules(GSTREAMER gstreamer-1.0)
 pkg_check_modules(GSTREAMER_BASE gstreamer-base-1.0)
@@ -391,6 +394,11 @@ optional_component(GIO ON "Devices: GIO device backend"
   DEPENDS "Unix or Windows" "NOT APPLE"
 )
 
+optional_component(GIO_UNIX ON "Devices: GIO device backend (Unix support)"
+  DEPENDS "libgio-unix" GIO_UNIX_FOUND
+  DEPENDS "Unix" "UNIX"
+)
+
 optional_component(LIBGPOD ON "Devices: iPod classic support"
   DEPENDS "libgpod" LIBGPOD_FOUND
   DEPENDS "gdk-pixbuf" GDK_PIXBUF_FOUND

src/CMakeLists.txt

@@ -986,6 +986,10 @@ if(HAVE_GIO)
   link_directories(${GIO_LIBRARY_DIRS})
 endif()
 
+if(HAVE_GIO_UNIX)
+  link_directories(${GIO_UNIX_LIBRARY_DIRS})
+endif()
+
 if(HAVE_AUDIOCD)
   link_directories(${LIBCDIO_LIBRARY_DIRS})
 endif()
@@ -1113,6 +1117,11 @@ if(HAVE_GIO)
   target_link_libraries(strawberry_lib PRIVATE ${GIO_LIBRARIES})
 endif()
 
+if(HAVE_GIO_UNIX)
+  target_include_directories(strawberry_lib SYSTEM PRIVATE ${GIO_UNIX_INCLUDE_DIRS})
+  target_link_libraries(strawberry_lib PRIVATE ${GIO_UNIX_LIBRARIES})
+endif()
+
 if(HAVE_AUDIOCD)
   target_include_directories(strawberry_lib SYSTEM PRIVATE ${LIBCDIO_INCLUDE_DIRS})
   target_link_libraries(strawberry_lib PRIVATE ${LIBCDIO_LIBRARIES})

src/config.h.in

@@ -7,6 +7,7 @@
 
 #cmakedefine HAVE_BACKTRACE
 #cmakedefine HAVE_GIO
+#cmakedefine HAVE_GIO_UNIX
 #cmakedefine HAVE_DBUS
 #cmakedefine HAVE_X11
 #cmakedefine HAVE_UDISKS2

src/device/giolister.cpp

@@ -25,6 +25,9 @@
 #include <glib.h>
 #include <glib-object.h>
 #include <gio/gio.h>
+#ifdef HAVE_GIO_UNIX
+#  include <gio/gunixmounts.h>
+#endif
 
 #include <QtGlobal>
 #include <QObject>
@@ -60,6 +63,8 @@ bool GioLister::DeviceInfo::is_suitable() const {
 
   if (!volume_ptr) return false;  // This excludes smb or ssh mounts
 
+  if (is_system_internal) return false;
+
   if (drive_ptr && !drive_removable) return false;  // This excludes internal drives
 
   if (filesystem_type.isEmpty()) return true;
@@ -447,7 +452,8 @@ void GioLister::DeviceInfo::ReadMountInfo(GMount *mount) {
   }
   g_object_unref(icon);
 
-  GFile *root = g_mount_get_root(mount);
+  ScopedGObject<GFile> root;
+  root.reset_without_add(g_mount_get_root(mount));
 
   // Get the mount path
   mount_path = ConvertAndFree(g_file_get_path(root));
@@ -466,6 +472,21 @@ void GioLister::DeviceInfo::ReadMountInfo(GMount *mount) {
     g_object_unref(actual_mount);
   }
 
+#ifdef HAVE_GIO_UNIX
+  GUnixMountEntry *unix_mount = g_unix_mount_for(g_file_get_path(root), NULL);
+  if (unix_mount) {
+    // the GIO's definition of system internal mounts include filesystems like
+    // autofs, tmpfs, sysfs, etc, and various system directories, including the root,
+    // /boot, /var, /home, etc.
+    is_system_internal = g_unix_mount_is_system_internal(unix_mount);
+    g_unix_mount_free(unix_mount);
+    // Although checking most of the internal mounts is safe,
+    // we really don't want to touch autofs filesystems, as that would
+    // trigger automounting.
+    if (is_system_internal) return;
+  }
+#endif
+
   // Query the filesystem info for size, free space, and type
   error = nullptr;
   GFileInfo *info = g_file_query_filesystem_info(root, G_FILE_ATTRIBUTE_FILESYSTEM_SIZE "," G_FILE_ATTRIBUTE_FILESYSTEM_FREE "," G_FILE_ATTRIBUTE_FILESYSTEM_TYPE, nullptr, &error);
@@ -494,9 +515,6 @@ void GioLister::DeviceInfo::ReadMountInfo(GMount *mount) {
       g_object_unref(info);
     }
   }
-
-  g_object_unref(root);
-
 }
 
 void GioLister::DeviceInfo::ReadVolumeInfo(GVolume *volume) {

src/device/giolister.h

@@ -77,7 +77,7 @@ class GioLister : public DeviceLister {
 
  private:
   struct DeviceInfo {
-    DeviceInfo() : drive_removable(false), filesystem_size(0), filesystem_free(0), invalid_enclosing_mount(false) {}
+    DeviceInfo() : drive_removable(false), filesystem_size(0), filesystem_free(0), invalid_enclosing_mount(false), is_system_internal(false) {}
 
     QString unique_id() const;
     bool is_suitable() const;
@@ -111,6 +111,7 @@ class GioLister : public DeviceLister {
     QString filesystem_type;
 
     bool invalid_enclosing_mount;
+    bool is_system_internal;
   };
 
   void VolumeAdded(GVolume *volume);