1 files changed, 1029 insertions, 0 deletions

diff --git a/scripts/lib/mic/utils/fs_related.py b/scripts/lib/mic/utils/fs_related.py
new file mode 100644
index 0000000000..b9b9a97175
--- /dev/null
+++ b/scripts/lib/mic/utils/fs_related.py
@@ -0,0 +1,1029 @@
+#!/usr/bin/python -tt
+#
+# Copyright (c) 2007, Red Hat, Inc.
+# Copyright (c) 2009, 2010, 2011 Intel, 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; version 2 of the License
+#
+# 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., 59
+# Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+from __future__ import with_statement
+import os
+import sys
+import errno
+import stat
+import random
+import string
+import time
+import uuid
+
+from mic import msger
+from mic.utils import runner
+from mic.utils.errors import *
+
+
+def find_binary_inchroot(binary, chroot):
+    paths = ["/usr/sbin",
+             "/usr/bin",
+             "/sbin",
+             "/bin"
+            ]
+
+    for path in paths:
+        bin_path = "%s/%s" % (path, binary)
+        if os.path.exists("%s/%s" % (chroot, bin_path)):
+            return bin_path
+    return None
+
+def find_binary_path(binary):
+    if os.environ.has_key("PATH"):
+        paths = os.environ["PATH"].split(":")
+    else:
+        paths = []
+        if os.environ.has_key("HOME"):
+            paths += [os.environ["HOME"] + "/bin"]
+        paths += ["/usr/local/sbin", "/usr/local/bin", "/usr/sbin", "/usr/bin", "/sbin", "/bin"]
+
+    for path in paths:
+        bin_path = "%s/%s" % (path, binary)
+        if os.path.exists(bin_path):
+            return bin_path
+    raise CreatorError("Command '%s' is not available." % binary)
+
+def makedirs(dirname):
+    """A version of os.makedirs() that doesn't throw an
+    exception if the leaf directory already exists.
+    """
+    try:
+        os.makedirs(dirname)
+    except OSError, err:
+        if err.errno != errno.EEXIST:
+            raise
+
+def mksquashfs(in_img, out_img):
+    fullpathmksquashfs = find_binary_path("mksquashfs")
+    args = [fullpathmksquashfs, in_img, out_img]
+
+    if not sys.stdout.isatty():
+        args.append("-no-progress")
+
+    ret = runner.show(args)
+    if ret != 0:
+        raise SquashfsError("'%s' exited with error (%d)" % (' '.join(args), ret))
+
+def resize2fs(fs, size):
+    resize2fs = find_binary_path("resize2fs")
+    if size == 0:
+        # it means to minimalize it
+        return runner.show([resize2fs, '-M', fs])
+    else:
+        return runner.show([resize2fs, fs, "%sK" % (size / 1024,)])
+
+def my_fuser(fp):
+    fuser = find_binary_path("fuser")
+    if not os.path.exists(fp):
+        return False
+
+    rc = runner.quiet([fuser, "-s", fp])
+    if rc == 0:
+        for pid in runner.outs([fuser, fp]).split():
+            fd = open("/proc/%s/cmdline" % pid, "r")
+            cmdline = fd.read()
+            fd.close()
+            if cmdline[:-1] == "/bin/bash":
+                return True
+
+    # not found
+    return False
+
+class BindChrootMount:
+    """Represents a bind mount of a directory into a chroot."""
+    def __init__(self, src, chroot, dest = None, option = None):
+        self.root = os.path.abspath(os.path.expanduser(chroot))
+        self.option = option
+
+        self.orig_src = self.src = src
+        if os.path.islink(src):
+            self.src = os.readlink(src)
+            if not self.src.startswith('/'):
+                self.src = os.path.abspath(os.path.join(os.path.dirname(src),
+                                                        self.src))
+
+        if not dest:
+            dest = self.src
+        self.dest = os.path.join(self.root, dest.lstrip('/'))
+
+        self.mounted = False
+        self.mountcmd = find_binary_path("mount")
+        self.umountcmd = find_binary_path("umount")
+
+    def ismounted(self):
+        with open('/proc/mounts') as f:
+            for line in f:
+                if line.split()[1] == os.path.abspath(self.dest):
+                    return True
+
+        return False
+
+    def has_chroot_instance(self):
+        lock = os.path.join(self.root, ".chroot.lock")
+        return my_fuser(lock)
+
+    def mount(self):
+        if self.mounted or self.ismounted():
+            return
+
+        makedirs(self.dest)
+        rc = runner.show([self.mountcmd, "--bind", self.src, self.dest])
+        if rc != 0:
+            raise MountError("Bind-mounting '%s' to '%s' failed" %
+                             (self.src, self.dest))
+        if self.option:
+            rc = runner.show([self.mountcmd, "--bind", "-o", "remount,%s" % self.option, self.dest])
+            if rc != 0:
+                raise MountError("Bind-remounting '%s' failed" % self.dest)
+
+        self.mounted = True
+        if os.path.islink(self.orig_src):
+            dest = os.path.join(self.root, self.orig_src.lstrip('/'))
+            if not os.path.exists(dest):
+                os.symlink(self.src, dest)
+
+    def unmount(self):
+        if self.has_chroot_instance():
+            return
+
+        if self.ismounted():
+            runner.show([self.umountcmd, "-l", self.dest])
+        self.mounted = False
+
+class LoopbackMount:
+    """LoopbackMount  compatibility layer for old API"""
+    def __init__(self, lofile, mountdir, fstype = None):
+        self.diskmount = DiskMount(LoopbackDisk(lofile,size = 0),mountdir,fstype,rmmountdir = True)
+        self.losetup = False
+        self.losetupcmd = find_binary_path("losetup")
+
+    def cleanup(self):
+        self.diskmount.cleanup()
+
+    def unmount(self):
+        self.diskmount.unmount()
+
+    def lounsetup(self):
+        if self.losetup:
+            runner.show([self.losetupcmd, "-d", self.loopdev])
+            self.losetup = False
+            self.loopdev = None
+
+    def loopsetup(self):
+        if self.losetup:
+            return
+
+        self.loopdev = get_loop_device(self.losetupcmd, self.lofile)
+        self.losetup = True
+
+    def mount(self):
+        self.diskmount.mount()
+
+class SparseLoopbackMount(LoopbackMount):
+    """SparseLoopbackMount  compatibility layer for old API"""
+    def __init__(self, lofile, mountdir, size, fstype = None):
+        self.diskmount = DiskMount(SparseLoopbackDisk(lofile,size),mountdir,fstype,rmmountdir = True)
+
+    def expand(self, create = False, size = None):
+        self.diskmount.disk.expand(create, size)
+
+    def truncate(self, size = None):
+        self.diskmount.disk.truncate(size)
+
+    def create(self):
+        self.diskmount.disk.create()
+
+class SparseExtLoopbackMount(SparseLoopbackMount):
+    """SparseExtLoopbackMount  compatibility layer for old API"""
+    def __init__(self, lofile, mountdir, size, fstype, blocksize, fslabel):
+        self.diskmount = ExtDiskMount(SparseLoopbackDisk(lofile,size), mountdir, fstype, blocksize, fslabel, rmmountdir = True)
+
+
+    def __format_filesystem(self):
+        self.diskmount.__format_filesystem()
+
+    def create(self):
+        self.diskmount.disk.create()
+
+    def resize(self, size = None):
+        return self.diskmount.__resize_filesystem(size)
+
+    def mount(self):
+        self.diskmount.mount()
+
+    def __fsck(self):
+        self.extdiskmount.__fsck()
+
+    def __get_size_from_filesystem(self):
+        return self.diskmount.__get_size_from_filesystem()
+
+    def __resize_to_minimal(self):
+        return self.diskmount.__resize_to_minimal()
+
+    def resparse(self, size = None):
+        return self.diskmount.resparse(size)
+
+class Disk:
+    """Generic base object for a disk
+
+    The 'create' method must make the disk visible as a block device - eg
+    by calling losetup. For RawDisk, this is obviously a no-op. The 'cleanup'
+    method must undo the 'create' operation.
+    """
+    def __init__(self, size, device = None):
+        self._device = device
+        self._size = size
+
+    def create(self):
+        pass
+
+    def cleanup(self):
+        pass
+
+    def get_device(self):
+        return self._device
+    def set_device(self, path):
+        self._device = path
+    device = property(get_device, set_device)
+
+    def get_size(self):
+        return self._size
+    size = property(get_size)
+
+
+class RawDisk(Disk):
+    """A Disk backed by a block device.
+    Note that create() is a no-op.
+    """
+    def __init__(self, size, device):
+        Disk.__init__(self, size, device)
+
+    def fixed(self):
+        return True
+
+    def exists(self):
+        return True
+
+class LoopbackDisk(Disk):
+    """A Disk backed by a file via the loop module."""
+    def __init__(self, lofile, size):
+        Disk.__init__(self, size)
+        self.lofile = lofile
+        self.losetupcmd = find_binary_path("losetup")
+
+    def fixed(self):
+        return False
+
+    def exists(self):
+        return os.path.exists(self.lofile)
+
+    def create(self):
+        if self.device is not None:
+            return
+
+        self.device = get_loop_device(self.losetupcmd, self.lofile)
+
+    def cleanup(self):
+        if self.device is None:
+            return
+        msger.debug("Losetup remove %s" % self.device)
+        rc = runner.show([self.losetupcmd, "-d", self.device])
+        self.device = None
+
+class SparseLoopbackDisk(LoopbackDisk):
+    """A Disk backed by a sparse file via the loop module."""
+    def __init__(self, lofile, size):
+        LoopbackDisk.__init__(self, lofile, size)
+
+    def expand(self, create = False, size = None):
+        flags = os.O_WRONLY
+        if create:
+            flags |= os.O_CREAT
+            if not os.path.exists(self.lofile):
+                makedirs(os.path.dirname(self.lofile))
+
+        if size is None:
+            size = self.size
+
+        msger.debug("Extending sparse file %s to %d" % (self.lofile, size))
+        if create:
+            fd = os.open(self.lofile, flags, 0644)
+        else:
+            fd = os.open(self.lofile, flags)
+
+        if size <= 0:
+            size = 1
+        try:
+            os.ftruncate(fd, size)
+        except:
+            # may be limited by 2G in 32bit env
+            os.ftruncate(fd, 2**31L)
+
+        os.close(fd)
+
+    def truncate(self, size = None):
+        if size is None:
+            size = self.size
+
+        msger.debug("Truncating sparse file %s to %d" % (self.lofile, size))
+        fd = os.open(self.lofile, os.O_WRONLY)
+        os.ftruncate(fd, size)
+        os.close(fd)
+
+    def create(self):
+        self.expand(create = True)
+        LoopbackDisk.create(self)
+
+class Mount:
+    """A generic base class to deal with mounting things."""
+    def __init__(self, mountdir):
+        self.mountdir = mountdir
+
+    def cleanup(self):
+        self.unmount()
+
+    def mount(self, options = None):
+        pass
+
+    def unmount(self):
+        pass
+
+class DiskMount(Mount):
+    """A Mount object that handles mounting of a Disk."""
+    def __init__(self, disk, mountdir, fstype = None, rmmountdir = True):
+        Mount.__init__(self, mountdir)
+
+        self.disk = disk
+        self.fstype = fstype
+        self.rmmountdir = rmmountdir
+
+        self.mounted = False
+        self.rmdir   = False
+        if fstype:
+            self.mkfscmd = find_binary_path("mkfs." + self.fstype)
+        else:
+            self.mkfscmd = None
+        self.mountcmd = find_binary_path("mount")
+        self.umountcmd = find_binary_path("umount")
+
+    def cleanup(self):
+        Mount.cleanup(self)
+        self.disk.cleanup()
+
+    def unmount(self):
+        if self.mounted:
+            msger.debug("Unmounting directory %s" % self.mountdir)
+            runner.quiet('sync') # sync the data on this mount point
+            rc = runner.show([self.umountcmd, "-l", self.mountdir])
+            if rc == 0:
+                self.mounted = False
+            else:
+                raise MountError("Failed to umount %s" % self.mountdir)
+        if self.rmdir and not self.mounted:
+            try:
+                os.rmdir(self.mountdir)
+            except OSError, e:
+                pass
+            self.rmdir = False
+
+
+    def __create(self):
+        self.disk.create()
+
+
+    def mount(self, options = None):
+        if self.mounted:
+            return
+
+        if not os.path.isdir(self.mountdir):
+            msger.debug("Creating mount point %s" % self.mountdir)
+            os.makedirs(self.mountdir)
+            self.rmdir = self.rmmountdir
+
+        self.__create()
+
+        msger.debug("Mounting %s at %s" % (self.disk.device, self.mountdir))
+        if options:
+            args = [ self.mountcmd, "-o", options, self.disk.device, self.mountdir ]
+        else:
+            args = [ self.mountcmd, self.disk.device, self.mountdir ]
+        if self.fstype:
+            args.extend(["-t", self.fstype])
+
+        rc = runner.show(args)
+        if rc != 0:
+            raise MountError("Failed to mount '%s' to '%s' with command '%s'. Retval: %s" %
+                             (self.disk.device, self.mountdir, " ".join(args), rc))
+
+        self.mounted = True
+
+class ExtDiskMount(DiskMount):
+    """A DiskMount object that is able to format/resize ext[23] filesystems."""
+    def __init__(self, disk, mountdir, fstype, blocksize, fslabel, rmmountdir=True, skipformat = False, fsopts = None):
+        DiskMount.__init__(self, disk, mountdir, fstype, rmmountdir)
+        self.blocksize = blocksize
+        self.fslabel = fslabel.replace("/", "")
+        self.uuid = str(uuid.uuid4())
+        self.skipformat = skipformat
+        self.fsopts = fsopts
+        self.extopts = None
+        self.dumpe2fs = find_binary_path("dumpe2fs")
+        self.tune2fs = find_binary_path("tune2fs")
+
+    def __parse_field(self, output, field):
+        for line in output.split("\n"):
+            if line.startswith(field + ":"):
+                return line[len(field) + 1:].strip()
+
+        raise KeyError("Failed to find field '%s' in output" % field)
+
+    def __format_filesystem(self):
+        if self.skipformat:
+            msger.debug("Skip filesystem format.")
+            return
+
+        msger.verbose("Formating %s filesystem on %s" % (self.fstype, self.disk.device))
+        cmdlist = [self.mkfscmd, "-F", "-L", self.fslabel, "-m", "1", "-b",
+                   str(self.blocksize), "-U", self.uuid]
+        if self.extopts:
+            cmdlist.extend(self.extopts.split())
+        cmdlist.extend([self.disk.device])
+
+        rc, errout = runner.runtool(cmdlist, catch=2)
+        if rc != 0:
+            raise MountError("Error creating %s filesystem on disk %s:\n%s" %
+                             (self.fstype, self.disk.device, errout))
+
+        if not self.extopts:
+            msger.debug("Tuning filesystem on %s" % self.disk.device)
+            runner.show([self.tune2fs, "-c0", "-i0", "-Odir_index", "-ouser_xattr,acl", self.disk.device])
+
+    def __resize_filesystem(self, size = None):
+        current_size = os.stat(self.disk.lofile)[stat.ST_SIZE]
+
+        if size is None:
+            size = self.disk.size
+
+        if size == current_size:
+            return
+
+        if size > current_size:
+            self.disk.expand(size)
+
+        self.__fsck()
+
+        resize2fs(self.disk.lofile, size)
+        return size
+
+    def __create(self):
+        resize = False
+        if not self.disk.fixed() and self.disk.exists():
+            resize = True
+
+        self.disk.create()
+
+        if resize:
+            self.__resize_filesystem()
+        else:
+            self.__format_filesystem()
+
+    def mount(self, options = None):
+        self.__create()
+        DiskMount.mount(self, options)
+
+    def __fsck(self):
+        msger.info("Checking filesystem %s" % self.disk.lofile)
+        runner.quiet(["/sbin/e2fsck", "-f", "-y", self.disk.lofile])
+
+    def __get_size_from_filesystem(self):
+        return int(self.__parse_field(runner.outs([self.dumpe2fs, '-h', self.disk.lofile]),
+                                      "Block count")) * self.blocksize
+
+    def __resize_to_minimal(self):
+        self.__fsck()
+
+        #
+        # Use a binary search to find the minimal size
+        # we can resize the image to
+        #
+        bot = 0
+        top = self.__get_size_from_filesystem()
+        while top != (bot + 1):
+            t = bot + ((top - bot) / 2)
+
+            if not resize2fs(self.disk.lofile, t):
+                top = t
+            else:
+                bot = t
+        return top
+
+    def resparse(self, size = None):
+        self.cleanup()
+        if size == 0:
+            minsize = 0
+        else:
+            minsize = self.__resize_to_minimal()
+            self.disk.truncate(minsize)
+
+        self.__resize_filesystem(size)
+        return minsize
+
+class VfatDiskMount(DiskMount):
+    """A DiskMount object that is able to format vfat/msdos filesystems."""
+    def __init__(self, disk, mountdir, fstype, blocksize, fslabel, rmmountdir=True, skipformat = False, fsopts = None):
+        DiskMount.__init__(self, disk, mountdir, fstype, rmmountdir)
+        self.blocksize = blocksize
+        self.fslabel = fslabel.replace("/", "")
+        rand1 = random.randint(0, 2**16 - 1)
+        rand2 = random.randint(0, 2**16 - 1)
+        self.uuid = "%04X-%04X" % (rand1, rand2)
+        self.skipformat = skipformat
+        self.fsopts = fsopts
+        self.fsckcmd = find_binary_path("fsck." + self.fstype)
+
+    def __format_filesystem(self):
+        if self.skipformat:
+            msger.debug("Skip filesystem format.")
+            return
+
+        msger.verbose("Formating %s filesystem on %s" % (self.fstype, self.disk.device))
+        rc = runner.show([self.mkfscmd, "-n", self.fslabel,
+                          "-i", self.uuid.replace("-", ""), self.disk.device])
+        if rc != 0:
+            raise MountError("Error creating %s filesystem on disk %s" % (self.fstype,self.disk.device))
+
+        msger.verbose("Tuning filesystem on %s" % self.disk.device)
+
+    def __resize_filesystem(self, size = None):
+        current_size = os.stat(self.disk.lofile)[stat.ST_SIZE]
+
+        if size is None:
+            size = self.disk.size
+
+        if size == current_size:
+            return
+
+        if size > current_size:
+            self.disk.expand(size)
+
+        self.__fsck()
+
+        #resize2fs(self.disk.lofile, size)
+        return size
+
+    def __create(self):
+        resize = False
+        if not self.disk.fixed() and self.disk.exists():
+            resize = True
+
+        self.disk.create()
+
+        if resize:
+            self.__resize_filesystem()
+        else:
+            self.__format_filesystem()
+
+    def mount(self, options = None):
+        self.__create()
+        DiskMount.mount(self, options)
+
+    def __fsck(self):
+        msger.debug("Checking filesystem %s" % self.disk.lofile)
+        runner.show([self.fsckcmd, "-y", self.disk.lofile])
+
+    def __get_size_from_filesystem(self):
+        return self.disk.size
+
+    def __resize_to_minimal(self):
+        self.__fsck()
+
+        #
+        # Use a binary search to find the minimal size
+        # we can resize the image to
+        #
+        bot = 0
+        top = self.__get_size_from_filesystem()
+        return top
+
+    def resparse(self, size = None):
+        self.cleanup()
+        minsize = self.__resize_to_minimal()
+        self.disk.truncate(minsize)
+        self.__resize_filesystem(size)
+        return minsize
+
+class BtrfsDiskMount(DiskMount):
+    """A DiskMount object that is able to format/resize btrfs filesystems."""
+    def __init__(self, disk, mountdir, fstype, blocksize, fslabel, rmmountdir=True, skipformat = False, fsopts = None):
+        self.__check_btrfs()
+        DiskMount.__init__(self, disk, mountdir, fstype, rmmountdir)
+        self.blocksize = blocksize
+        self.fslabel = fslabel.replace("/", "")
+        self.uuid  = None
+        self.skipformat = skipformat
+        self.fsopts = fsopts
+        self.blkidcmd = find_binary_path("blkid")
+        self.btrfsckcmd = find_binary_path("btrfsck")
+
+    def __check_btrfs(self):
+        found = False
+        """ Need to load btrfs module to mount it """
+        load_module("btrfs")
+        for line in open("/proc/filesystems").xreadlines():
+            if line.find("btrfs") > -1:
+                found = True
+                break
+        if not found:
+            raise MountError("Your system can't mount btrfs filesystem, please make sure your kernel has btrfs support and the module btrfs.ko has been loaded.")
+
+        # disable selinux, selinux will block write
+        if os.path.exists("/usr/sbin/setenforce"):
+            runner.show(["/usr/sbin/setenforce", "0"])
+
+    def __parse_field(self, output, field):
+        for line in output.split(" "):
+            if line.startswith(field + "="):
+                return line[len(field) + 1:].strip().replace("\"", "")
+
+        raise KeyError("Failed to find field '%s' in output" % field)
+
+    def __format_filesystem(self):
+        if self.skipformat:
+            msger.debug("Skip filesystem format.")
+            return
+
+        msger.verbose("Formating %s filesystem on %s" % (self.fstype, self.disk.device))
+        rc = runner.show([self.mkfscmd, "-L", self.fslabel, self.disk.device])
+        if rc != 0:
+            raise MountError("Error creating %s filesystem on disk %s" % (self.fstype,self.disk.device))
+
+        self.uuid = self.__parse_field(runner.outs([self.blkidcmd, self.disk.device]), "UUID")
+
+    def __resize_filesystem(self, size = None):
+        current_size = os.stat(self.disk.lofile)[stat.ST_SIZE]
+
+        if size is None:
+            size = self.disk.size
+
+        if size == current_size:
+            return
+
+        if size > current_size:
+            self.disk.expand(size)
+
+        self.__fsck()
+        return size
+
+    def __create(self):
+        resize = False
+        if not self.disk.fixed() and self.disk.exists():
+            resize = True
+
+        self.disk.create()
+
+        if resize:
+            self.__resize_filesystem()
+        else:
+            self.__format_filesystem()
+
+    def mount(self, options = None):
+        self.__create()
+        DiskMount.mount(self, options)
+
+    def __fsck(self):
+        msger.debug("Checking filesystem %s" % self.disk.lofile)
+        runner.quiet([self.btrfsckcmd, self.disk.lofile])
+
+    def __get_size_from_filesystem(self):
+        return self.disk.size
+
+    def __resize_to_minimal(self):
+        self.__fsck()
+
+        return self.__get_size_from_filesystem()
+
+    def resparse(self, size = None):
+        self.cleanup()
+        minsize = self.__resize_to_minimal()
+        self.disk.truncate(minsize)
+        self.__resize_filesystem(size)
+        return minsize
+
+class DeviceMapperSnapshot(object):
+    def __init__(self, imgloop, cowloop):
+        self.imgloop = imgloop
+        self.cowloop = cowloop
+
+        self.__created = False
+        self.__name = None
+        self.dmsetupcmd = find_binary_path("dmsetup")
+
+        """Load dm_snapshot if it isn't loaded"""
+        load_module("dm_snapshot")
+
+    def get_path(self):
+        if self.__name is None:
+            return None
+        return os.path.join("/dev/mapper", self.__name)
+    path = property(get_path)
+
+    def create(self):
+        if self.__created:
+            return
+
+        self.imgloop.create()
+        self.cowloop.create()
+
+        self.__name = "imgcreate-%d-%d" % (os.getpid(),
+                                           random.randint(0, 2**16))
+
+        size = os.stat(self.imgloop.lofile)[stat.ST_SIZE]
+
+        table = "0 %d snapshot %s %s p 8" % (size / 512,
+                                             self.imgloop.device,
+                                             self.cowloop.device)
+
+        args = [self.dmsetupcmd, "create", self.__name, "--table", table]
+        if runner.show(args) != 0:
+            self.cowloop.cleanup()
+            self.imgloop.cleanup()
+            raise SnapshotError("Could not create snapshot device using: " + ' '.join(args))
+
+        self.__created = True
+
+    def remove(self, ignore_errors = False):
+        if not self.__created:
+            return
+
+        time.sleep(2)
+        rc = runner.show([self.dmsetupcmd, "remove", self.__name])
+        if not ignore_errors and rc != 0:
+            raise SnapshotError("Could not remove snapshot device")
+
+        self.__name = None
+        self.__created = False
+
+        self.cowloop.cleanup()
+        self.imgloop.cleanup()
+
+    def get_cow_used(self):
+        if not self.__created:
+            return 0
+
+        #
+        # dmsetup status on a snapshot returns e.g.
+        #   "0 8388608 snapshot 416/1048576"
+        # or, more generally:
+        #   "A B snapshot C/D"
+        # where C is the number of 512 byte sectors in use
+        #
+        out = runner.outs([self.dmsetupcmd, "status", self.__name])
+        try:
+            return int((out.split()[3]).split('/')[0]) * 512
+        except ValueError:
+            raise SnapshotError("Failed to parse dmsetup status: " + out)
+
+def create_image_minimizer(path, image, minimal_size):
+    """
+    Builds a copy-on-write image which can be used to
+    create a device-mapper snapshot of an image where
+    the image's filesystem is as small as possible
+
+    The steps taken are:
+      1) Create a sparse COW
+      2) Loopback mount the image and the COW
+      3) Create a device-mapper snapshot of the image
+         using the COW
+      4) Resize the filesystem to the minimal size
+      5) Determine the amount of space used in the COW
+      6) Restroy the device-mapper snapshot
+      7) Truncate the COW, removing unused space
+      8) Create a squashfs of the COW
+    """
+    imgloop = LoopbackDisk(image, None) # Passing bogus size - doesn't matter
+
+    cowloop = SparseLoopbackDisk(os.path.join(os.path.dirname(path), "osmin"),
+                                 64L * 1024L * 1024L)
+
+    snapshot = DeviceMapperSnapshot(imgloop, cowloop)
+
+    try:
+        snapshot.create()
+
+        resize2fs(snapshot.path, minimal_size)
+
+        cow_used = snapshot.get_cow_used()
+    finally:
+        snapshot.remove(ignore_errors = (not sys.exc_info()[0] is None))
+
+    cowloop.truncate(cow_used)
+
+    mksquashfs(cowloop.lofile, path)
+
+    os.unlink(cowloop.lofile)
+
+def load_module(module):
+    found = False
+    for line in open('/proc/modules').xreadlines():
+        if line.startswith("%s " % module):
+            found = True
+            break
+    if not found:
+        msger.info("Loading %s..." % module)
+        runner.quiet(['modprobe', module])
+
+class LoopDevice(object):
+    def __init__(self, loopid=None):
+        self.device = None
+        self.loopid = loopid
+        self.created = False
+        self.kpartxcmd = find_binary_path("kpartx")
+        self.losetupcmd = find_binary_path("losetup")
+
+    def register(self, device):
+        self.device = device
+        self.loopid = None
+        self.created = True
+
+    def reg_atexit(self):
+        import atexit
+        atexit.register(self.close)
+
+    def _genloopid(self):
+        import glob
+        if not glob.glob("/dev/loop[0-9]*"):
+            return 10
+
+        fint = lambda x: x[9:].isdigit() and int(x[9:]) or 0
+        maxid = 1 + max(filter(lambda x: x<100,
+                               map(fint, glob.glob("/dev/loop[0-9]*"))))
+        if maxid < 10: maxid = 10
+        if maxid >= 100: raise
+        return maxid
+
+    def _kpseek(self, device):
+        rc, out = runner.runtool([self.kpartxcmd, '-l', '-v', device])
+        if rc != 0:
+            raise MountError("Can't query dm snapshot on %s" % device)
+        for line in out.splitlines():
+            if line and line.startswith("loop"):
+                return True
+        return False
+
+    def _loseek(self, device):
+        import re
+        rc, out = runner.runtool([self.losetupcmd, '-a'])
+        if rc != 0:
+            raise MountError("Failed to run 'losetup -a'")
+        for line in out.splitlines():
+            m = re.match("([^:]+): .*", line)
+            if m and m.group(1) == device:
+                return True
+        return False
+
+    def create(self):
+        if not self.created:
+            if not self.loopid:
+                self.loopid = self._genloopid()
+            self.device = "/dev/loop%d" % self.loopid
+            if os.path.exists(self.device):
+                if self._loseek(self.device):
+                    raise MountError("Device busy: %s" % self.device)
+                else:
+                    self.created = True
+                    return
+
+            mknod = find_binary_path('mknod')
+            rc = runner.show([mknod, '-m664', self.device, 'b', '7', str(self.loopid)])
+            if rc != 0:
+                raise MountError("Failed to create device %s" % self.device)
+            else:
+                self.created = True
+
+    def close(self):
+        if self.created:
+            try:
+                self.cleanup()
+                self.device = None
+            except MountError, e:
+                msger.error("%s" % e)
+
+    def cleanup(self):
+
+        if self.device is None:
+            return
+
+
+        if self._kpseek(self.device):
+            if self.created:
+                for i in range(3, os.sysconf("SC_OPEN_MAX")):
+                    try:
+                        os.close(i)
+                    except:
+                        pass
+            runner.quiet([self.kpartxcmd, "-d", self.device])
+        if self._loseek(self.device):
+            runner.quiet([self.losetupcmd, "-d", self.device])
+        # FIXME: should sleep a while between two loseek
+        if self._loseek(self.device):
+            msger.warning("Can't cleanup loop device %s" % self.device)
+        elif self.loopid:
+            os.unlink(self.device)
+
+DEVICE_PIDFILE_DIR = "/var/tmp/mic/device"
+DEVICE_LOCKFILE = "/var/lock/__mic_loopdev.lock"
+
+def get_loop_device(losetupcmd, lofile):
+    global DEVICE_PIDFILE_DIR
+    global DEVICE_LOCKFILE
+
+    import fcntl
+    makedirs(os.path.dirname(DEVICE_LOCKFILE))
+    fp = open(DEVICE_LOCKFILE, 'w')
+    fcntl.flock(fp, fcntl.LOCK_EX)
+    try:
+        loopdev = None
+        devinst = LoopDevice()
+
+        # clean up left loop device first
+        clean_loop_devices()
+
+        # provide an avaible loop device
+        rc, out = runner.runtool([losetupcmd, "--find"])
+        if rc == 0:
+            loopdev = out.split()[0]
+            devinst.register(loopdev)
+        if not loopdev or not os.path.exists(loopdev):
+            devinst.create()
+            loopdev = devinst.device
+
+        # setup a loop device for image file
+        rc = runner.show([losetupcmd, loopdev, lofile])
+        if rc != 0:
+            raise MountError("Failed to setup loop device for '%s'" % lofile)
+
+        devinst.reg_atexit()
+
+        # try to save device and pid
+        makedirs(DEVICE_PIDFILE_DIR)
+        pidfile = os.path.join(DEVICE_PIDFILE_DIR, os.path.basename(loopdev))
+        if os.path.exists(pidfile):
+            os.unlink(pidfile)
+        with open(pidfile, 'w') as wf:
+            wf.write(str(os.getpid()))
+
+    except MountError, err:
+        raise CreatorError("%s" % str(err))
+    except:
+        raise
+    finally:
+        try:
+            fcntl.flock(fp, fcntl.LOCK_UN)
+            fp.close()
+            os.unlink(DEVICE_LOCKFILE)
+        except:
+            pass
+
+    return loopdev
+
+def clean_loop_devices(piddir=DEVICE_PIDFILE_DIR):
+    if not os.path.exists(piddir) or not os.path.isdir(piddir):
+        return
+
+    for loopdev in os.listdir(piddir):
+        pidfile = os.path.join(piddir, loopdev)
+        try:
+            with open(pidfile, 'r') as rf:
+                devpid = int(rf.read())
+        except:
+            devpid = None
+
+        # if the process using this device is alive, skip it
+        if not devpid or os.path.exists(os.path.join('/proc', str(devpid))):
+            continue
+
+        # try to clean it up
+        try:
+            devinst = LoopDevice()
+            devinst.register(os.path.join('/dev', loopdev))
+            devinst.cleanup()
+            os.unlink(pidfile)
+        except:
+            pass
+