Turns out I had confused myself about the situation. Just because a page
has been paged in by another process doesn't mean that the *current*
process's page directory has the present bit set! D'oh. :^)
This exposed a serious race condition in page_in_from_inode().
Reordered the logic and added a paging lock to VMObject.
Now, only one process can page in from a VMObject at a time.
There are definitely ways to optimize this, for instance by making
the locking be per-page instead. It's not something that I'm going
to worry about right now though.
This only works with the userspace build of SharedGraphics so far.
It's also very slow at loading fonts, but that's easy to fix.
Let's put fonts in /res/fonts/.
GObjects can now register a timer with the GEventLoop. This will eventually
cause GTimerEvents to be dispatched to the GObject.
This needed a few supporting changes in the kernel:
- The PIT now ticks 1000 times/sec.
- select() now supports an arbitrary timeout.
- gettimeofday() now returns something in the tv_usec field.
With these changes, the clock window in guitest2 finally ticks on its own.
Use this to fix a use-after-free in ~GraphicsBitmap(). We'd hit this when
the WindowServer was doing a deferred destruction of a WSWindow whose
backing store referred to a now-reaped Process.
FileDescriptor will now keep a pointer to the original inode even after
opening it resolves to a character device.
Fixed up /bin/ls to display major and minor device numbers instead of size
for device files.
Previously, calling Region::commit() would make sure to allocate any missing
physical pages, but they would contain uninitialized data. This was very
obvious when allocating GraphicsBitmaps as they would have garbage pixels
rather than being filled with black.
The MM quickmap mechanism didn't work when operating on a non-active page
directory (which happens when we're in the middle of exec, for example.)
This patch changes quickmap to reside in the shared kernel page directory.
Also added some missing clobber lists to inline asm that I stumbled on.
This ownership model is a bit confusing. There's a retain cycle between
MasterPTY and SlavePTY, but it's broken when the SlavePTY is closed, meaning
that there are no more FileDescriptors referring to it.
This required a fair bit of plumbing. The CharacterDevice::close() virtual
will now be closed by ~FileDescriptor(), allowing device implementations to
do custom cleanup at that point.
One big problem remains: if the master PTY is closed before the slave PTY,
we go into crashy land.
You're never gonna be right 100% of the time when guessing how much buffer
space you need. This avoids having to make that type of decision in a bunch
of cases. :^)
You can now open as many PTY pairs as you like. Well, it's actually capped
at 8 for now, but it's just a constant and trivial to change.
Unregistering a PTY pair is untested because I didn't want to start
mucking with that in Terminal right now.
Only raw octal modes are supported right now.
This patch also changes mode_t from 32-bit to 16-bit to match the on-disk
type used by Ext2FS.
I also ran into EPERM being errno=0 which was confusing, so I inserted an
ESUCCESS in its place.
