X-Git-Url: https://code.grnet.gr/git/snf-image-creator/blobdiff_plain/1377b8a73a91437cc4a51e91afadd30deb783a19..c16922f7c1676fff006b360b60fc495e268031bf:/image_creator/disk.py diff --git a/image_creator/disk.py b/image_creator/disk.py index 4a6b78f..809a1a3 100644 --- a/image_creator/disk.py +++ b/image_creator/disk.py @@ -1,6 +1,8 @@ #!/usr/bin/env python -import losetup +from image_creator.util import get_command +from clint.textui import progress + import stat import os import tempfile @@ -9,15 +11,27 @@ import re import sys import guestfs -from pbs import dmsetup -from pbs import blockdev -from pbs import dd -class DiskError(Exception): pass +class DiskError(Exception): + pass + +dd = get_command('dd') +dmsetup = get_command('dmsetup') +losetup = get_command('losetup') +blockdev = get_command('blockdev') + class Disk(object): + """This class represents a hard disk hosting an Operating System + + A Disk instance never alters the source media it is created from. + Any change is done on a snapshot created by the device-mapper of + the Linux kernel. + """ def __init__(self, source): + """Create a new Disk instance out of a source media. The source + media can be an image file, a block device or a directory.""" self._cleanup_jobs = [] self._devices = [] self.source = source @@ -26,24 +40,32 @@ class Disk(object): self._cleanup_jobs.append((job, args)) def _losetup(self, fname): - loop = losetup.find_unused_loop_device() - loop.mount(fname) - self._add_cleanup(loop.unmount) - return loop.device + loop = losetup('-f', '--show', fname) + loop = loop.strip() # remove the new-line char + self._add_cleanup(losetup, '-d', loop) + return loop def _dir_to_disk(self): raise NotImplementedError def cleanup(self): + """Cleanup internal data. This needs to be called before the + program ends. + """ while len(self._devices): device = self._devices.pop() device.destroy() - + while len(self._cleanup_jobs): job, args = self._cleanup_jobs.pop() job(*args) def get_device(self): + """Returns a newly created DiskDevice instance. + + This instance is a snapshot of the original source media of + the Disk instance. + """ sourcedev = self.source mode = os.stat(self.source).st_mode if stat.S_ISDIR(mode): @@ -57,8 +79,8 @@ class Disk(object): size = blockdev('--getsize', sourcedev) cowfd, cow = tempfile.mkstemp() self._add_cleanup(os.unlink, cow) - # Create 1G cow file - dd('if=/dev/null', 'of=%s' % cow, 'bs=1k' ,'seek=%d' % (1024*1024)) + # Create 1G cow sparse file + dd('if=/dev/null', 'of=%s' % cow, 'bs=1k', 'seek=%d' % (1024 * 1024)) cowdev = self._losetup(cow) snapshot = uuid.uuid4().hex @@ -76,18 +98,43 @@ class Disk(object): return new_device def destroy_device(self, device): + """Destroys a DiskDevice instance previously created by + get_device method. + """ self._devices.remove(device) device.destroy() + +def progress_generator(total): + position = 0; + for i in progress.bar(range(total)): + if i < position: + continue + position = yield + yield #suppress the StopIteration exception + + class DiskDevice(object): + """This class represents a block device hosting an Operating System + as created by the device-mapper. + """ - def __init__(self, device, bootable = True): + def __init__(self, device, bootable=True): + """Create a new DiskDevice.""" self.device = device self.bootable = bootable + self.progress_bar = None self.g = guestfs.GuestFS() - self.g.add_drive_opts(device, readonly = 0) + self.g.add_drive_opts(device, readonly=0) + + #self.g.set_trace(1) + #self.g.set_verbose(1) + + eh = self.g.set_event_callback(self.progress_callback, guestfs.EVENT_PROGRESS) self.g.launch() + self.g.delete_event_callback(eh) + roots = self.g.inspect_os() if len(roots) == 0: raise DiskError("No operating system found") @@ -95,28 +142,42 @@ class DiskDevice(object): raise DiskError("Multiple operating systems found") self.root = roots[0] - + self.ostype = self.g.inspect_get_type(self.root) + self.distro = self.g.inspect_get_distro(self.root) + def destroy(self): + """Destroy this DiskDevice instance.""" self.g.umount_all() self.g.sync() # Close the guestfs handler - del self.g - - def get_image_metadata(self): - meta = {} - meta["OSFAMILY"] = self.g.inspect_get_type(self.root) - meta["OS"] = self.g.inspect_get_distro(self.root) - meta["description"] = self.g.inspect_get_product_name(self.root) - return meta + self.g.close() + + def progress_callback(self, ev, eh, buf, array): + position = array[2] + total = array[3] + + if self.progress_bar is None: + self.progress_bar = progress_generator(total) + self.progress_bar.next() + + self.progress_bar.send(position) + + if position == total: + self.progress_bar = None def mount(self): - mps = g.inspect_get_mountpoints(self.root) + """Mount all disk partitions in a correct order.""" + mps = self.g.inspect_get_mountpoints(self.root) + # Sort the keys to mount the fs in a correct order. # / should be mounted befor /boot, etc - 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 + 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: @@ -124,4 +185,60 @@ class DiskDevice(object): except RuntimeError as msg: print "%s (ignored)" % msg + def umount(self): + """Umount all mounted filesystems.""" + self.g.umount_all() + + def shrink(self): + """Shrink the disk. + + This is accomplished by shrinking the last filesystem in the + disk and then updating the partition table. The new disk size + (in bytes) is returned. + """ + dev = self.g.part_to_dev(self.root) + parttype = self.g.part_get_parttype(dev) + if parttype != 'msdos': + raise DiskError("You have a %s partition table. " + "Only msdos partitions are supported" % parttype) + + last_partition = self.g.part_list(dev)[-1] + + if last_partition['part_num'] > 4: + raise DiskError("This disk contains logical partitions. " + "Only primary partitions are supported.") + + part_dev = "%s%d" % (dev, last_partition['part_num']) + fs_type = self.g.vfs_type(part_dev) + if not re.match("ext[234]", fs_type): + print "Warning: Don't know how to resize %s partitions." % vfs_type + return + + self.g.e2fsck_f(part_dev) + self.g.resize2fs_M(part_dev) + output = self.g.tune2fs_l(part_dev) + block_size = int(filter(lambda x: x[0] == 'Block size', output)[0][1]) + block_cnt = int(filter(lambda x: x[0] == 'Block count', output)[0][1]) + + sector_size = self.g.blockdev_getss(dev) + + start = last_partition['part_start'] / sector_size + end = start + (block_size * block_cnt) / sector_size - 1 + + self.g.part_del(dev, last_partition['part_num']) + self.g.part_add(dev, 'p', start, end) + + return (end + 1) * sector_size + + def size(self): + """Returns the "payload" size of the device. + + The size returned by this method is the size of the space occupied by + the partitions (including the space before the first partition). + """ + dev = self.g.part_to_dev(self.root) + last = self.g.part_list(dev)[-1] + + return last['part_end'] + # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :