We were only destroying the main thread when a process died, leaving any
secondary threads around. They couldn't run, but because they were still
in the global thread list, strange things could happen since they had some
now-stale pointers to their old process.
Calling systrace(pid) gives you a file descriptor with a stream of the
syscalls made by a peer process. The process must be owned by the same
UID who calls systrace(). :^)
I was originally implementing signals by looking at some man page about
sigaction() to see how it works. It seems like the restorer thingy is
system-specific and not required by POSIX, so let's get rid of it.
If connect() is called on a non-blocking socket, it will "fail" immediately
with -EINPROGRESS. After that, you select() on the socket and wait for it to
become writable.
We can't have multiple threads in the same process running in the kernel
at the same time, so let's have a per-process lock that threads have to
acquire on syscall entry/exit (and yield while blocked.)
This currently only works for "normal" processes created by fork().
It does not work for create_user_process() processes spawned by the
kernel, as those are a bit special during construction.
It's basically a userspace port of the kernel's Lock class.
Added gettid() and donate() syscalls to support the timeslice donation
feature we already enjoyed in the kernel.
This introduces a tiny amount of timer drift which I will have to fix
somehow eventually, but it's a huge improvement in timing consistency
as we no longer suddenly jump from e.g 10:45:49.123 to 10:45:50.000.
The scheduler now operates on threads, rather than on processes.
Each process has a main thread, and can have any number of additional
threads. The process exits when the main thread exits.
This patch doesn't actually spawn any additional threads, it merely
does all the plumbing needed to make it possible. :^)
Now that everything is nice and mature, the WindowServer can just use the
client PID it receives in the Greeting message, and we can get rid of this
hacky ioctl. :^)
This is accomplished using a new Alarm class and a BlockedSnoozing state.
Basically, you call Process::snooze_until(some_alarm) and then the scheduler
won't wake up the process until some_alarm.is_ringing() returns true.
We had a bug where an accepted socket would appear to be EOF/disconnected
on the accepting side until the connecting side had called attach_fd().
Fix this by adding a new SocketRole::Connecting state.
