Until now, OSV's console defaulted to raw mode, to make the CLI
happy. The problem is that on Linux, applications expect to be
run in cooked mode, so if we ever run a simple application that
tries to read user input, it can be confused.

This patch makes OSV console default to cooked mode, and the
CLI switch to raw mode before reading an input line - and reset
to the default mode just before running the user's command.

Unfortunately, we had to resort to adding a JNI class "Stty",
since Java has no builtin support for the ioctls required for
changing the tty settings.

Two SPECjvm2008 benchmarks (compiler.compiler and compiler.sunflow)
hang (and rarely crash) when the filesystem is accessed concurrently
from multiple threads. The synthetic test tst-vfs.c, committed
earlier, demonstrates the same bug with a trivial test where 10
threads concurrently call the stat() system call on the same file.

This patch fixes this bug. In the existing VFS code, a vnode's
reference count is protected not by the node's own mutex, but rather
by the global vnode lock. In one case, the reference count was
modified (and worse, non-atomically) from outside the lock.
Taking the lock a bit earlier fixed both the benchmarks and the
synthetic test.

This is a modified version of zlib for use by ZFS.

This isn't actually a BSD native API as FreeBSD uses a per-cpu variable
to store cpuids, but rather a replacement we can use.

The caller - virtio_if_start already calls kick after it loops
over all the qeueued tx msgs.

in the next patch it's going to be used by an initialization script.

uses Java nio.* for downloading a file, writing it to /tmp

requires starting qemu with tap networking, first install libvirt
then launch the run script as root with the -n option.

Example:

$ sudo ./scripts/run.py -d -n

in osv you'll have to configure networking as follows:

$ ifconfig virtio-net0 192.168.122.100 netmask 255.255.255.0 up
$ route add default gw 192.168.122.1

will be used to set the default gateway or set a network route
for example by doing:

route add -net x.x.x.x netmask x.x.x.x gw x.x.x.x

apparently when qemu is started with networking the tty isn't restored
successfully, this patch handles this

needs libvirt installed, expects to find virbr0

laying out the base for increased complexity in the run script, it
will performs various IT operations as setting up networking in
the future.

SIOCSIFFLAGS should be sent in anyway in order to initialize the interface,
the SIOCGIFFLAGS returned IFF_UP for some reason so it should be further
investigated, add a fixme for now

While trying to run the "compiler.compiler" benchmark from SPECjvm2008,
I noticed we seem to have a problem with concurrent use of filesystem
operations - which often hang (waiting on a vn_lock()) or cause
assertion failures.

This trivial test - which does stat() calls in 10 concurrent threads -
reproduces this bug, and usually (but not always) crashes on one of
several assertion failures, or hangs.

APIs. In particular, the "crypto.aes" and "crypto.rsa" benchmarks
fail without them.

At some point, we should consider just adding most of the stuff in
/usr/lib/jvm/java/jre/lib to our distribution... Everything in that
directory has to be useful for something, and it might take a while
before we try all possible APIs in OSV...

the lack of extern "C").

This is a way to sleep without a wakeup channel.

I had to rename the symbol to bsd_pause because it conflicts with the classic
Unix pause syscall exposed through unistd.h via libcstd++.