virt-manager/src/virtManager/inspection.py

#
# Copyright (C) 2011 Red Hat, Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
# MA 02110-1301 USA.
#

from Queue import Queue, Empty
from threading import Thread
import logging
import os

import gobject

from guestfs import GuestFS

from virtManager.baseclass import vmmGObject

class vmmInspection(vmmGObject):
    # Can't find a way to make Thread release our reference
    _leak_check = False

    def __init__(self):
        vmmGObject.__init__(self)

        self._thread = Thread(name="inspection thread", target=self._run)
        self._thread.daemon = True
        self._wait = 15 * 1000 # 15 seconds

        self._q = Queue()
        self._conns = dict()
        self._vmseen = dict()

    def cleanup(self):
        try:
            vmmGObject.cleanup(self)

            self._thread = None
            self._q = Queue()
            self._conns = {}
            self._vmseen = {}
        except:
            pass

    # Called by the main thread whenever a connection is added or
    # removed.  We tell the inspection thread, so it can track
    # connections.
    def conn_added(self, engine_ignore, conn):
        obj = ("conn_added", conn)
        self._q.put(obj)

    def conn_removed(self, engine_ignore, uri):
        obj = ("conn_removed", uri)
        self._q.put(obj)

    # Called by the main thread whenever a VM is added to vmlist.
    def vm_added(self, conn, uuid):
        ignore = conn
        ignore = uuid
        obj = ("vm_added")
        self._q.put(obj)

    def start(self):
        # Wait a few seconds before we do anything.  This prevents
        # inspection from being a burden for initial virt-manager
        # interactivity (although it shouldn't affect interactivity at
        # all).
        def cb():
            self._thread.start()
            return 0

        logging.debug("waiting")
        self.add_gobject_timeout(gobject.timeout_add(self._wait, cb))

    def _run(self):
        while True:
            logging.debug("ready")
            self._process_queue()
            self._process_vms()

    # Process everything on the queue.  If the queue is empty when
    # called, block.
    def _process_queue(self):
        first_obj = self._q.get()
        self._process_queue_item(first_obj)
        self._q.task_done()
        try:
            while True:
                obj = self._q.get(False)
                self._process_queue_item(obj)
                self._q.task_done()
        except Empty:
            pass

    def _process_queue_item(self, obj):
        if obj[0] == "conn_added":
            conn = obj[1]
            if conn and not (conn.is_remote()):
                uri = conn.get_uri()
                self._conns[uri] = conn
                conn.connect("vm-added", self.vm_added)
        elif obj[0] == "conn_removed":
            uri = obj[1]
            del self._conns[uri]
        elif obj[0] == "vm_added":
            # Nothing - just a signal for the inspection thread to wake up.
            pass

    # Any VMs we've not seen yet?  If so, process them.
    def _process_vms(self):
        for conn in self._conns.itervalues():
            for vmuuid in conn.list_vm_uuids():
                if not (vmuuid in self._vmseen):
                    prettyvm = vmuuid
                    try:
                        vm = conn.get_vm(vmuuid)
                        prettyvm = conn.get_uri() + ":" + vm.get_name()

                        logging.debug("%s: processing started" % prettyvm)
                        # Whether success or failure, we've "seen" this VM now.
                        self._vmseen[vmuuid] = True
                        self._process(conn, vm, vmuuid)
                    except:
                        logging.exception("%s: exception while processing" %
                                          prettyvm)
                    logging.debug("%s: processing done" % prettyvm)

    def _process(self, conn, vm, vmuuid):
        g = GuestFS()
        prettyvm = conn.get_uri() + ":" + vm.get_name()
        ignore = vmuuid

        disks = []
        for disk in vm.get_disk_devices():
            if (disk.path and
                (disk.type == "block" or disk.type == "file")):
                disks.append(disk)

        if not disks:
            # Nothing to inspect!
            return

        # Add the disks.  Note they *must* be added with readonly flag set.
        for disk in disks:
            path = disk.path
            driver_type = disk.driver_type

            if not (os.path.exists(path) and os.access(path, os.R_OK)):
                logging.debug("%s: cannot access '%s', skipping inspection",
                              prettyvm, path)
                return

            g.add_drive_opts(path, readonly=1, format=driver_type)

        g.launch()

        # Inspect the operating system.
        roots = g.inspect_os()
        if len(roots) == 0:
            logging.debug("%s: no operating systems found", prettyvm)
            return

        # Arbitrarily pick the first root device.
        root = roots[0]

        # Inspection results.
        typ = g.inspect_get_type(root) # eg. "linux"
        distro = g.inspect_get_distro(root) # eg. "fedora"
        major_version = g.inspect_get_major_version(root) # eg. 14
        minor_version = g.inspect_get_minor_version(root) # eg. 0
        hostname = g.inspect_get_hostname(root) # string
        product_name = g.inspect_get_product_name(root) # string

        # Added in libguestfs 1.9.13:
        product_variant = None
        if hasattr(g, "inspect_get_product_variant"):
            product_variant = g.inspect_get_product_variant(root) # string

        # For inspect_list_applications and inspect_get_icon we
        # require that the guest filesystems are mounted.  However
        # don't fail if this is not possible (I'm looking at you,
        # FreeBSD).
        filesystems_mounted = False
        try:
            # Mount up the disks, like guestfish --ro -i.

            # Sort keys by length, shortest first, so that we end up
            # mounting the filesystems in the correct order.
            mps = g.inspect_get_mountpoints(root)
            def compare(a, b):
                if len(a[0]) > len(b[0]):
                    return 1
                elif len(a[0]) == len(b[0]):
                    return 0
                else:
                    return -1
            mps.sort(compare)

            for mp_dev in mps:
                try:
                    g.mount_ro(mp_dev[1], mp_dev[0])
                except:
                    logging.exception("exception mounting %s on %s "
                                      "(ignored)" % (mp_dev[1], mp_dev[0]))

            filesystems_mounted = True
        except:
            logging.exception("exception while mounting disks (ignored)")

        icon = None
        apps = None
        if filesystems_mounted:
            # Added in libguestfs 1.11.12:
            if hasattr(g, "inspect_get_icon"):
                # string containing PNG data
                icon = g.inspect_get_icon(root, favicon=0, highquality=1)
                if icon == "":
                    icon = None

            # Inspection applications.
            apps = g.inspect_list_applications(root)

        # Force the libguestfs handle to close right now.
        del g

        vm.inspection.type = typ
        vm.inspection.distro = distro
        vm.inspection.major_version = major_version
        vm.inspection.minor_version = minor_version
        vm.inspection.hostname = hostname
        vm.inspection.product_name = product_name
        vm.inspection.product_variant = product_variant
        vm.inspection.icon = icon
        vm.inspection.applications = apps

        vm.inspection_data_updated()

        # Log what we found.
        logging.debug("detected operating system: %s %s %d.%d (%s)",
                      typ, distro, major_version, minor_version, product_name)
        logging.debug("hostname: %s", hostname)
        if icon:
            logging.debug("icon: %d bytes", len(icon))
        if apps:
            logging.debug("# apps: %d", len(apps))

vmmGObject.type_register(vmmInspection)