Fix bugs in bundle_volume module
[snf-image-creator] / image_creator / bundle_volume.py
index 2051738..15f16ad 100644 (file)
 # interpreted as representing official policies, either expressed
 # or implied, of GRNET S.A.
 
+import os
+import re
+import uuid
+import tempfile
+from collections import namedtuple
+
+import parted
+
+from image_creator.util import get_command
 from image_creator.util import FatalError
 
-def bundle_volume():
-    raise FatalError("Creating an image out of a running system is not yet "
-        "supported.")
+findfs = get_command('findfs')
+truncate = get_command('truncate')
+dd = get_command('dd')
+dmsetup = get_command('dmsetup')
+
+
+class BundleVolume():
+    _FileSystemEntry = namedtuple('FileSystemEntry',
+                                  'dev mpoint fs opts freq passno')
+
+    _Partition = namedtuple('Partition', 'num start end type fs mopts')
+
+    def __init__(self, out, meta):
+        self.out = out
+        self.meta = meta
+
+        self.out.output('Searching for root device ...', False)
+        root = self._get_root_partition()
+
+        if root.startswith("UUID=") or root.startswith("LABEL="):
+            self.root = findfs(root).stdout.strip()
+        else:
+            self.root = root
+
+        if not re.match('/dev/[hsv]d[a-z][1-9]*$', self.root):
+            raise FatalError("Don't know how to handle root device: %s" % \
+                             self.root)
+
+        self.disk = re.split('[0-9]', self.root)[0]
+
+        out.success('%s' % self.root)
+
+    def _read_fstable(self, f):
+        if not os.path.isfile(f):
+            raise FatalError("Unable to open: `%s'. File is missing." % f)
+
+        with open(f) as table:
+            for line in iter(table):
+                entry = line.split('#')[0].strip().split()
+                if len(entry) != 6:
+                    continue
+                yield self._FileSystemEntry(*entry)
+
+    def _get_root_partition(self):
+        for entry in self._read_fstable('/etc/fstab'):
+            if entry.mpoint == '/':
+                return entry.dev
+
+        raise FatalError("Unable to find root device in /etc/fstab")
+
+    def _is_mpoint(self, path):
+        for entry in self._read_fstable('/proc/mounts'):
+            if entry.mpoint == path:
+                return True
+        return False
+
+    def _mount_options(self, device):
+        for entry in self._read_fstable('/proc/mounts'):
+            if not entry.dev.startswith('/'):
+                continue
+
+            if os.path.realpath(entry.dev) == os.path.realpath(device):
+                return entry
+
+        return
+
+    def _create_partition_table(self, src_disk, dest_file):
+
+        if src_disk.type != 'msdos':
+            raise FatalError('Only msdos partition tables are supported')
+
+        first_sector = src_disk.getPrimaryPartitions()[0].geometry.start
+
+        # Copy the MBR and the space between the MBR and the first partition.
+        # In Grub version 1 Stage 1.5 is located there.
+        first_sector = src_disk.getPrimaryPartitions()[0].geometry.start
+
+        dd('if=%s' % src_disk.device.path, 'of=%s' % dest_file,
+           'bs=%d' % src_disk.device.sectorSize,
+           'count=%d' % first_sector, 'conv=notrunc')
+
+        # Create the Extended boot records (EBRs) in the image
+        extended = src_disk.getExtendedPartition()
+        if not extended:
+            return
+
+        # Extended boot records precede the logical partitions they describe
+        logical = src_disk.getLogicalPartitions()
+        start = extended.geometry.start
+        for i in range(len(logical)):
+            end = logical[i].geometry.start - 1
+            dd('if=%s' % src_disk.device.path, 'of=%s' % dest_file,
+               'count=%d' % (end - start + 1), 'conv=notrunc',
+               'seek=%d' % start, 'skip=%d' % start)
+            start = logical[i].geometry.end + 1
+
+    def _shrink_partitions(self, src_disk, image_file):
+
+        partitions = []
+        new_end = 0
+
+        image_dev = parted.Device(image_file)
+        image_disk = parted.Disk(image_dev)
+
+        is_extended = lambda p: p.type == parted.PARTITION_EXTENDED
+        is_logical = lambda p: p.type == parted.PARTITION_LOGICAL
+
+        partitions = []
+        for p in src_disk.partitions:
+            g = p.geometry
+            f = p.fileSystem
+            partitions.append(self._Partition(p.number, g.start, g.end,
+                              p.type, f.type if f is not None else '',
+                              self._mount_options(p.path)))
+
+        last = partitions[-1]
+        new_end = src_disk.device.getLength()
+        if last.fs == 'linux-swap(v1)':
+            MB = 2 ** 20
+            size = (last.end - last.start + 1) * src_disk.device.sectorSize
+            self.meta['SWAP'] = "%d:%s" % (last.num, (size + MB - 1) // MB)
+
+            image_disk.deletePartition(
+                image_disk.getPartitionBySector(last.start))
+            image_disk.commit()
+
+            if is_logical(last) and last.num == 5:
+                extended = image_disk.getExtendedPartition()
+                image_disk.deletePartition(extended)
+                image_disk.commit()
+                partitions.remove(filter(is_extended, partitions)[0])
+
+            partitions.remove(last)
+            last = partitions[-1]
+
+            # Leave 2048 blocks at the end
+            new_end = last.end + 2048
+
+        if last.mopts.mpoint:
+            stat = os.statvfs(last.mopts.mpoint)
+            # Shrink the last partition. The new size should be the
+            # size of the occupied blocks
+            blcks = stat.f_blocks - stat.f_bavail
+            new_size = (blcks * stat.f_frsize) // src_disk.device.sectorSize
+
+            # Add 10% just to be on the safe side
+            part_end = last.start + (new_size * 11) // 10
+            # Alighn to 2048
+            part_end = ((part_end + 2047) // 2048) * 2048
+            last = last._replace(end=part_end)
+            partitions[-1] = last
+
+            # Leave 2048 blocks at the end.
+            new_end = new_size + 2048
+
+            image_disk.setPartitionGeometry(
+                image_disk.getPartitionBySector(last.start),
+                parted.Constraint(device=image_disk.device),
+                start=last.start, end=last.end)
+            image_disk.commit()
+
+            if last.type == parted.PARTITION_LOGICAL:
+                # Fix the extended partition
+                extended = disk.getExtendedPartition()
+
+                image_disk.setPartitionGeometry(extended,
+                    parted.Constraint(device=img_dev),
+                    ext.geometry.start, end=last.end)
+                image_disk.commit()
+
+        # Check if the available space is enough to host the image
+        location = os.path.dirname(image_file)
+        size = (new_end + 1) * src_disk.device.sectorSize
+        self.out.output("Examining available space in %s..." % location, False)
+        stat = os.statvfs(location)
+        available = stat.f_bavail * stat.f_frsize
+        if available <= size:
+            raise FatalError('Not enough space in %s to host the image' % \
+                             location)
+        self.out.success("sufficient")
+
+        return partitions
+
+    def _fill_partitions(self, src_disk, image, partitions):
+        pass
+
+    def create_image(self):
+
+        image_file = '/mnt/%s.diskdump' % uuid.uuid4().hex
+
+        src_dev = parted.Device(self.disk)
+
+        size = src_dev.getLength() * src_dev.sectorSize
+
+        # Create sparse file to host the image
+        truncate("-s", "%d" % size, image_file)
+
+        src_disk = parted.Disk(src_dev)
+        self._create_partition_table(src_disk, image_file)
+        partitions = self._shrink_partitions(src_disk, image_file)
+        self._fill_partitions(src_disk, image_file, partitions)
+
+        return image_file
+
+#      unmounted = filter(lambda p: not p.mopts.mpoint, partitions)
+#        mounted = filter(lambda p: p.mopts.mpoint, partitions)
+#
+#        for p in unmounted:
+#            dd('if=%s' % src_dev.path, 'of=%s' % img_dev.path,
+#               'count=%d' % (p.end - p.start + 1), 'conv=notrunc',
+#                'seek=%d' % p.start, 'skip=%d' % p.start)
+#
+#        partition_devices = create_devices(dest, partitions)
+#
+#        mounted.sort(key=lambda p: p.mopts.mpoint)
+#
+#        return img
 
 # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :