Commit Graph

13 Commits

Author SHA1 Message Date
Ehmry - a635873568 VFS: Replace global response handlers with local handlers
Replace the I/O response handler that is passed to the VFS at
construction with an object that is dynamically attached to handles.
This object shall also accept read-ready notifications, and plugins are
encouraged to keep handles awaiting ready-ready notifications separate
from handles that await I/O progress.

Replace the use of handle lists in plugins with handle queues, this
makes the code easier to understand and the ordering of notifications to
the application more explicit.

These changes replace the use of the Post_signal_hook from all VFS
plugins, applications must assume that read-ready and I/O notifications
occur during I/O signal dispatch and use an Io_progress_handler at its
entrypoints to defer response until after signal dispatching.

Fix #3257
2019-04-09 12:30:34 +02:00
Ehmry - 800b4e44b1 Reduce Vfs::Vfs_handle::Context to empty struct type
The "Vfs::Vfs_handle" type should not contain any public members that
can be initialized by the VFS internally and by the application, so
remove inheritance from the "Genode::list::Element" class. The VFS
plugins must instead use lists of "Vfs::Vfs_handle" sub-classes, the
lifetime of which are always managed by the plugin.

Ref #3036
2019-04-01 19:33:47 +02:00
Ehmry - 0b980073c1 VFS: close handles via handle method
The using pattern 'handle->close' is less error prone than attempting
'handle->ds().close(handle)' or 'fs.close(handle)'.

Ref #2782
2018-05-03 15:31:57 +02:00
Ehmry - 9c6b720ec1 Notification support for the VFS library
Add a new 'Vfs_watch_handle' type to the VFS interface. This handle type
will pass a handle context up through the I/O handler to the application
when a notification event occurs.

Watch support implemented for RAM and File_system plugins, all other
file-systems return WATCH_ERR_STATIC by default.

Test at run/fs_rom_update_ram and run/fs_rom_update_fs.

Fix #1934
2018-04-10 11:11:51 +02:00
Norman Feske eba9c15746 Follow practices suggested by "Effective C++"
The patch adjust the code of the base, base-<kernel>, and os repository.
To adapt existing components to fix violations of the best practices
suggested by "Effective C++" as reported by the -Weffc++ compiler
argument. The changes follow the patterns outlined below:

* A class with virtual functions can no longer publicly inherit base
  classed without a vtable. The inherited object may either be moved
  to a member variable, or inherited privately. The latter would be
  used for classes that inherit 'List::Element' or 'Avl_node'. In order
  to enable the 'List' and 'Avl_tree' to access the meta data, the
  'List' must become a friend.

* Instead of adding a virtual destructor to abstract base classes,
  we inherit the new 'Interface' class, which contains a virtual
  destructor. This way, single-line abstract base classes can stay
  as compact as they are now. The 'Interface' utility resides in
  base/include/util/interface.h.

* With the new warnings enabled, all member variables must be explicitly
  initialized. Basic types may be initialized with '='. All other types
  are initialized with braces '{ ... }' or as class initializers. If
  basic types and non-basic types appear in a row, it is nice to only
  use the brace syntax (also for basic types) and align the braces.

* If a class contains pointers as members, it must now also provide a
  copy constructor and assignment operator. In the most cases, one
  would make them private, effectively disallowing the objects to be
  copied. Unfortunately, this warning cannot be fixed be inheriting
  our existing 'Noncopyable' class (the compiler fails to detect that
  the inheriting class cannot be copied and still gives the error).
  For now, we have to manually add declarations for both the copy
  constructor and assignment operator as private class members. Those
  declarations should be prepended with a comment like this:

        /*
         * Noncopyable
         */
        Thread(Thread const &);
        Thread &operator = (Thread const &);

  In the future, we should revisit these places and try to replace
  the pointers with references. In the presence of at least one
  reference member, the compiler would no longer implicitly generate
  a copy constructor. So we could remove the manual declaration.

Issue #465
2018-01-17 12:14:35 +01:00
Christian Prochaska b0935ef9b2 VFS: nonblocking interface
The VFS library can be used in single-threaded or multi-threaded
environments and depending on that, signals are handled by the same thread
which uses the VFS library or possibly by a different thread. If a VFS
plugin needs to block to wait for a signal, there is currently no way
which works reliably in both environments.

For this reason, this commit makes the interface of the VFS library
nonblocking, similar to the File_system session interface.

The most important changes are:

- Directories are created and opened with the 'opendir()' function and the
  directory entries are read with the recently introduced 'queue_read()'
  and 'complete_read()' functions.

- Symbolic links are created and opened with the 'openlink()' function and
  the link target is read with the 'queue_read()' and 'complete_read()'
  functions and written with the 'write()' function.

- The 'write()' function does not wait for signals anymore. This can have
  the effect that data written by a VFS library user has not been
  processed by a file system server yet when the library user asks for the
  size of the file or closes it (both done with RPC functions at the file
  system server). For this reason, a user of the VFS library should
  request synchronization before calling 'stat()' or 'close()'. To make
  sure that a file system server has processed all write request packets
  which a client submitted before the synchronization request,
  synchronization is now requested at the file system server with a
  synchronization packet instead of an RPC function. Because of this
  change, the synchronization interface of the VFS library is now split
  into 'queue_sync()' and 'complete_sync()' functions.

Fixes #2399
2017-08-28 16:49:38 +02:00
Norman Feske 29b8d609c9 Adjust file headers to refer to the AGPLv3 2017-02-28 12:59:29 +01:00
Christian Helmuth 61b6dccf13 Queued read/write/read_ready in VFS and servers 2017-02-23 15:03:28 +01:00
Emery Hemingway 82a7799638 lib/vfs: pass handle allocator to open(...)
Opening a VFS handle previously involved allocating from the global heap
at each VFS file system. By amending open with an allocator argument,
dynamic allocation can be partitioned.

A new close method is used to deallocate open handles.

Issue #1751
Issue #1891
2016-04-11 12:56:54 +02:00
Sebastian Sumpf 06fe755f8c noux: Enable setting of file handle flags
Fixes #1765
2015-11-18 12:22:04 +01:00
Norman Feske 167925ab76 vfs: add Vfs_handle::Guard utility
Issue #1561
2015-06-09 11:00:11 +02:00
Alexander Boettcher 8b8c2713ae vfs: use 64bit for file offset and size
Fixes #1246
2014-10-10 13:02:28 +02:00
Norman Feske ca971bbfd8 Move repositories to 'repos/' subdirectory
This patch changes the top-level directory layout as a preparatory
step for improving the tools for managing 3rd-party source codes.
The rationale is described in the issue referenced below.

Issue #1082
2014-05-14 16:08:00 +02:00