FileHandle gets a hasDataAvailableForRead() getter.
If this returns true in sys$read(), the task will block(BlockedRead) + yield.
The fd blocked on is stored in Task::m_fdBlockedOnRead.
The scheduler then looks at the state of that fd during the unblock phase.
This makes "sh" restful. :^)
There's still some problem with the kernel not surviving the colonel task
getting scheduled. I need to figure that out and fix it.
It's implemented as a separate process. How cute is that.
Tasks now have a current working directory. Spawned tasks inherit their
parent task's working directory.
Currently everyone just uses "/" as there's no way to chdir().
I added a dead-simple malloc that only allows allocations < 4096 bytes.
It just forwards the request to mmap() every time.
I also added simplified versions of opendir() and readdir().
The naive spinlock was not nearly enough to protect kmalloc from
reentrancy problems.
I don't want to deal with coming up with a fancy lock for kmalloc
right now, so I made an InterruptDisabler thingy instead.
It does CLI and then STI iff interrupts were previously enabled.
I know I'm praying for cargo here, but this does fix a weird issue
where logging the sum_alloc and sum_free globals wouldn't display
symmetric values all the time.
Add a separate lock to protect the VFS. I think this might be a good idea.
I'm not sure it's a good approach though. I'll fiddle with it as I go along.
It's really fun to figure out all these things on my own.
- putch syscall now directly calls Console::putChar().
- /proc/summary includes some info about kmalloc stats.
- Syscall entry is guarded by a simple spinlock.
- Unmap regions for crashed tasks.
- Turn Keyboard into a CharacterDevice (85,1) at /dev/keyboard.
- Implement MM::unmapRegionsForTask() and MM::unmapRegion()
- Save SS correctly on interrupt.
- Add a simple Spawn syscall for launching another process.
- Move a bunch of IO syscall debug output behind DEBUG_IO.
- Have ASSERT do a "cli" immediately when failing.
This makes the output look proper every time.
- Implement a bunch of syscalls in LibC.
- Add a simple shell ("sh"). All it can do now is read a line
of text from /dev/keyboard and then try launching the specified
executable by calling spawn().
There are definitely bugs in here, but we're moving on forward.
- More work on funneling console output through Console.
- init() now breaks off into a separate task ASAP.
- ..this leaves the "colonel" task as a simple hlt idle loop.
- Mask all IRQs on startup (except IRQ2 for slave passthru)
- Fix underallocation bug in Task::allocateRegion().
- Remember how many times each Task has been scheduled.
The panel and scheduling banner are disabled until I get things
working nicely in the (brave) new Console world.
This leaves interrupts enabled while we're in the kernel, which is
precisely what we want.
This uncovered a horrendous problem with kernel tasks silently
overflowing their stacks. For now I've simply increased the stack size
but I need a more MMU-y solution for this eventually.
