#!/usr/bin/python

#Copyright 2012 Citrix Systems, Inc. Licensed under the 
#Apache License, Version 2.0 (the "License"); you may not use this
#file except in compliance with the License.  Citrix Systems, Inc.
#reserves all rights not expressly granted by the License.
#You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
#Unless required by applicable law or agreed to in writing, software
#distributed under the License is distributed on an "AS IS" BASIS,
#WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#See the License for the specific language governing permissions and 
#limitations under the License.

from xen.lowlevel import xs

def do_cloexec(fd):
	from fcntl import fcntl, F_GETFD, F_SETFD, FD_CLOEXEC

	ret = fcntl(fd, F_GETFD, FD_CLOEXEC)
	if ret < 0:
		return
	fcntl(fd, F_SETFD, ret|FD_CLOEXEC)

def write_dm_pid(domid, pid):
	store = xs.xs()
	store.write('', '/local/domain/%d/qemu-pid'%domid, '%d'%pid)

def is_sdk():
	try:
		store = xs.xs(socket=True)
		domid_as_dom0 = int(store.read('', 'domid'))
		store.close()
		assert domid_as_dom0 == 0
		store = xs.xs(xenbus=True)
		domid_on_host = int(store.read('', 'domid'))
		store.close()
		return domid_on_host != domid_as_dom0
	except:
		return False

def fake_dm(domid):
	from time import sleep
	from os import getpid

	store = xs.xs()

	store.write('', '/local/domain/%d/qemu-pid'%domid, '%d'%getpid())
	store.write('', '/local/domain/%d/device-misc/dm-ready'%domid, '1')
	store.write('', '/local/domain/%d/console/vnc-port'%domid, '%d'%(domid))

	while True:
		sleep(600)

	return 0

def cleanup(domid):
	from xen.lowlevel import xc
	hcall = xc.xc()

	print 'Unexpected termination, cleaning up...'

	try:
		hcall.domain_destroy(domid)
	except xc.Error:
		# we could have raced with another domain shutdown
		pass

def enable_core_dumps():
	from resource import getrlimit, RLIMIT_CORE, setrlimit

	limit = 64 * 1024 * 1024
	oldlimits = getrlimit(RLIMIT_CORE)
	setrlimit(RLIMIT_CORE, (limit, oldlimits[1]))
	return limit

def main(argv):
	import os

	qemu_env = os.environ
	qemu_dm = '/usr/lib/xen/bin/qemu-dm'
	domid = int(argv[1])
	qemu_args = ['qemu-dm-%d'%domid] + argv[2:]
        try:
            vnc_idx = qemu_args.index("-vnc")
            del qemu_args[vnc_idx: vnc_idx+2]
            qemu_args.insert(vnc_idx, "0.0.0.0:1")
            qemu_args.insert(vnc_idx, "-vnc")
        except ValueError, IndexError:
            pass

	if is_sdk() is True:
		return fake_dm(domid)

	print "qemu-dm-wrapper in python:"
	print "Using domid: %d" % domid
	print "Arguments: %s" % " ".join(argv[1:])
	print "everything else is from qemu-dm:"

	core_dump_limit = enable_core_dumps()
	print "core dump limit: %d" % core_dump_limit

	write_dm_pid(domid, os.getpid())

	os.dup2(1, 2)
	os.execve(qemu_dm, qemu_args, qemu_env)

if __name__ == '__main__':
	from sys import argv
	raise SystemExit, main(argv)