In order to move the WindowServer to userspace, I have to eliminate its
dependence on system call facilities. The communication channel with each
client needs to be message-based in both directions.
For now, the WindowServer process will run with high priority,
while the Finalizer process will run with low priority.
Everyone else gets to be "normal".
At the moment, priority simply determines the size of your time slices.
Since we know who's holding the lock, and we're gonna have to yield anyway,
we can just ask the scheduler to donate any remaining ticks to that process.
Instead of processes themselves getting scheduled to finish dying,
let's have a Finalizer process that wakes up whenever someone is dying.
This way we can do all kinds of lock-taking in process cleanup without
risking reentering the scheduler.
- Don't cli() in Process::do_exec() unless current is execing.
Eventually this should go away once the scheduler is less retarded
in the face of interrupts.
- Improved memory access validation for ring0 processes.
We now look at the kernel ELF header to determine if an access
is appropriate. :^) It's very hackish but also kinda neat.
- Have Process::die() put the process into a new "Dying" state where
it can still get scheduled but no signals will be dispatched.
This way we can keep executing in die() but won't get our EIP
hijacked by signal dispatch. The main problem here was that die()
wanted to take various locks.
Instead of cowboy-calling the VESA BIOS in the bootloader, find the emulator
VGA adapter by scanning the PCI bus. Then set up the desired video mode by
sending device commands.
Font now uses the same in-memory format as the font files we have on disk.
This allows us to simply mmap() the font files and not use any additional
memory for them. Very cool! :^)
Hacking on this exposed a bug in file-backed VMObjects where the first client
to instantiate a VMObject for a specific inode also got to decide its size.
Since file-backed VMObjects always have the same size as the underlying file,
this made no sense, so I removed the ability to even set a size in that case.
Also use an enum for the rather-confusing return value in dispatch_signal().
I will go through the rest of the signals and set them up with the
appropriate default dispositions at some other point.
Now the filesystem is generated on-the-fly instead of manually adding and
removing inodes as processes spawn and die.
The code is convoluted and bloated as I wrote it while sleepless. However,
it's still vastly better than the old ProcFS, so I'm committing it.
I also added /proc/PID/fd/N symlinks for each of a process's open fd's.
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.
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.
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.
It's really only supported in Ext2FS since SynthFS doesn't really want you
mucking around with its files. This is pretty neat though :^)
I ran into some trouble with HashMap while working on this but opted to work
around it and leave that for a separate investigation.
Instead of clients painting whenever they feel like it, we now ask that they
paint in response to a paint message.
After finishing painting, clients notify the WindowServer about the rect(s)
they painted into and then flush eventually happens, etc.
This stuff leaves us with a lot of badly named things. Need to fix that.
This means we only have to do one fill_rect() per line and the whole process
ends up being ~10% faster than before.
Also added a read_tsc() syscall to give userspace access to the TSC.
To start painting, call:
gui$get_window_backing_store()
Then finish up with:
gui$release_window_backing_store()
Process will retain the underlying GraphicsBitmap behind the scenes.
This fixes racing between the WindowServer and GUI clients.
This patch also adds a WSWindowLocker that is exactly what it sounds like.
This patch adds most of the plumbing for working file deletion in Ext2FS.
Directory entries are removed and inode link counts updated.
We don't yet update the inode or block bitmaps, I will do that separately.
Make PageDirectory retainable and have each Region co-own the PageDirectory
they're mapped into. When unmapped, Region has no associated PageDirectory.
This allows Region to automatically unmap itself when destroyed.
The system can finally idle without burning CPU. :^)
There are some issues with scheduling making the mouse cursor sloppy
and unresponsive that need to be dealt with.
This is pretty cool. :^)
GraphicsBitmaps are now mapped into both the server and the client address
space (usually at different addresses but that doesn't matter.)
Added a GUI syscall for getting a window's backing store, and another one
for invalidating a window so that the server redraws it.
Userspace programs can now open /dev/gui_events and read a stream of GUI_Event
structs one at a time.
I was stuck on a stupid problem where we'd reenter Scheduler::yield() due to
having one of the has_data_available_for_reading() implementations using locks.
