It's a very bad idea to increment the refcount on behalf of another
process. That process may (for either benign or evil reasons) not
reference the SharedBuffer, and then we'll be stuck with loads of
SharedBuffers until we OOM.
Instead, increment the refcount when the buffer is mapped. That way, a
buffer is only kept if *someone* has explicitly requested it via
get_shared_buffer.
Fixes#341
Generate a special page containing the "return from signal" trampoline code
on startup and then route signalled threads to it. This avoids a page
allocation in every process that ever receives a signal.
Region now has is_user_accessible(), which informs the memory manager how
to map these pages. Previously, we were just passing a "bool user_allowed"
to various functions and I'm not at all sure that any of that was correct.
All the Region constructors are now hidden, and you must go through one of
these helpers to construct a region:
- Region::create_user_accessible(...)
- Region::create_kernel_only(...)
That ensures that we don't accidentally create a Region without specifying
user accessibility. :^)
And use it in the scheduler.
IntrusiveList is similar to InlineLinkedList, except that rather than
making assertions about the type (and requiring inheritance), it
provides an IntrusiveListNode type that can be used to put an instance
into many different lists at once.
As a proof of concept, port the scheduler over to use it. The only
downside here is that the "list" global needs to know the position of
the IntrusiveListNode member, so we have to position things a little
awkwardly to make that happen. We also move the runnable lists to
Thread, to avoid having to publicize the node.
Committing some things my hands did while browsing through this code.
- Mark all leaf classes "final".
- FileDescriptionBlocker now stores a NonnullRefPtr<FileDescription>.
- FileDescriptionBlocker::blocked_description() now returns a reference.
- ConditionBlocker takes a Function&&.
"Blocking" is not terribly informative, but now that everything is
ported over, we can force the blocker to provide us with a reason.
This does mean that to_string(State) needed to become a member, but
that's OK.
Rolling with the theme of adding a dialog to shutdown the machine, it is
probably nice to have a way to reboot the machine without performing a full
system powerdown.
A reboot program has been added to `/bin/` as well as a corresponding
`syscall` (SC_reboot). This syscall works by attempting to pulse the 8042
keyboard controller. Note that this is NOT supported on new machines, and
should only be a fallback until we have proper ACPI support.
The implementation causes a triple fault in QEMU, which then restarts the
system. The filesystems are locked and synchronized before this occurs,
so there shouldn't be any corruption etctera.
The only part of this that actually differs between all of them is the
stream -> sample reading, so turn that into a function that the channel
reader can call as it wants.
BXVGADevice was using a Size object for its framebuffer size. We shouldn't
be pulling in userspace code in the kernel like this, even if it's just
headers. :^)
Instead of LibGUI and WindowServer building their own copies of the drawing
and graphics code, let's it in a separate LibDraw library.
This avoids building the code twice, and will encourage better separation
of concerns. :^)
This allows us to seal a buffer *before* anyone else has access to it
(well, ok, the creating process still does, but you can't win them all).
It also means that a SharedBuffer can be shared with multiple clients:
all you need is to have access to it to share it on again.
The to_foo() functions are for converting when you might not be sure of the
underlying value type. The as_foo() family assumes that you know exactly
what the underlying value type is.
This was a mistake, of course. Nested event loops don't need (or want)
independent server connections.
We initialize the connection early in GEventLoop for e.g. users that
want to get the size of a GDesktop before the connection has been
established.
Bug noticed by Andreas, introduced by me ;-)
Sticking these in a namespace allows us to use a more generic
("Connection") term without clashing, which is way easier to understand
than to try to come up with unique names for both.
As a consequence, move to use an explicit handshake() method rather than
calling virtuals from the constructor. This seemed to not bother
AClientConnection, but LibGUI crashes (rightfully) because of it.
The only reason for the inheritance was to add FDs to the select set.
Since CNotifier is available (and now also quite useful), we can make use of it
instead, and remove the inheritance.
