Since clone is no longer exists as a syscall, it makes little sense to
manage vfork in the kernel. Implementing vfork in userspace would still
be possible.
Because the way we were using inline assembly was technically incorrect
and breaking the laws of rust
This *finally* compiles. That doesn't mean it works!
This is a curious problem and it's really hard to solve it in a way
that doesn't feel hacky. On one hand, of course you want to be able to
modify and intercept what happens when you use a signal, right? On the
other hand, changes made to the context (especially singlestepping)
while a signal is handled (such as `SIGSTOP`) are not preserved since
the stack is restored after the signal handler was invoked.
I think what we have in this change makes sense anyway, as we don't
really want users modifying registers and other data in the default
signal behavior that occurs **in kernel mode**. Also trying to use
`PTRACE_SINGLESTEP` will set the singlestep flag only if in a
user-mode signal handler, else it will set it on the instruction after
the signal handling, which I guess makes sense since it can't affect
the kernel-mode code that runs the default handler.
I don't know. Help. Pls.
Since even a very basic ptrace can be nice to have, I thought I would split
the, perhaps rather big, ptrace project up in multiple PRs to make as few
changes as necessary in each. This PR contains the initial registry modifying
bits and only a very basic security measure. Letting this out to the community
should be good for spotting bugs and maybe getting some hype ;)