Support mounting freebsd ufs filesystems
[snf-image-creator] / image_creator / disk.py
index 01ff41d..b4311f8 100644 (file)
 # or implied, of GRNET S.A.
 
 from image_creator.util import get_command
-from image_creator.util import warn, progress, success, output, FatalError
+from image_creator.util import try_fail_repeat
+from image_creator.util import free_space
+from image_creator.util import FatalError
+from image_creator.bundle_volume import BundleVolume
+from image_creator.image import Image
 
 import stat
 import os
 import tempfile
 import uuid
-import re
-import sys
-import guestfs
-import time
-from sendfile import sendfile
-
-
-class DiskError(Exception):
-    pass
+import shutil
 
 dd = get_command('dd')
 dmsetup = get_command('dmsetup')
@@ -54,6 +50,9 @@ losetup = get_command('losetup')
 blockdev = get_command('blockdev')
 
 
+TMP_CANDIDATES = ['/var/tmp', os.path.expanduser('~'), '/mnt']
+
+
 class Disk(object):
     """This class represents a hard disk hosting an Operating System
 
@@ -62,280 +61,137 @@ class Disk(object):
     the Linux kernel.
     """
 
-    def __init__(self, source):
+    def __init__(self, source, output, tmp=None):
         """Create a new Disk instance out of a source media. The source
-        media can be an image file, a block device or a directory."""
+        media can be an image file, a block device or a directory.
+        """
         self._cleanup_jobs = []
-        self._devices = []
+        self._images = []
         self.source = source
+        self.out = output
+        self.meta = {}
+        self.tmp = tempfile.mkdtemp(prefix='.snf_image_creator.',
+                                    dir=self._get_tmp_dir(tmp))
+
+        self._add_cleanup(shutil.rmtree, self.tmp)
+
+    def _get_tmp_dir(self, default=None):
+        """Check tmp directory candidates and return the one with the most
+        available space.
+        """
+        if default is not None:
+            return default
+
+        space = map(free_space, TMP_CANDIDATES)
+
+        max_idx = 0
+        max_val = space[0]
+        for i, val in zip(range(len(space)), space):
+            if val > max_val:
+                max_val = val
+                max_idx = i
+
+        # Return the candidate path with more available space
+        return TMP_CANDIDATES[max_idx]
 
     def _add_cleanup(self, job, *args):
+        """Add a new job in the cleanup list"""
         self._cleanup_jobs.append((job, args))
 
     def _losetup(self, fname):
+        """Setup a loop device and add it to the cleanup list. The loop device
+        will be detached when cleanup is called.
+        """
         loop = losetup('-f', '--show', fname)
         loop = loop.strip()  # remove the new-line char
-        self._add_cleanup(losetup, '-d', loop)
+        self._add_cleanup(try_fail_repeat, losetup, '-d', loop)
         return loop
 
     def _dir_to_disk(self):
-        raise NotImplementedError
+        """Create a disk out of a directory"""
+        if self.source == '/':
+            bundle = BundleVolume(self.out, self.meta)
+            image = '%s/%s.diskdump' % (self.tmp, uuid.uuid4().hex)
+
+            def check_unlink(path):
+                if os.path.exists(path):
+                    os.unlink(path)
+
+            self._add_cleanup(check_unlink, image)
+            bundle.create_image(image)
+            return self._losetup(image)
+        raise FatalError("Using a directory as media source is supported")
 
     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.
+        try:
+            while len(self._images):
+                image = self._images.pop()
+                image.destroy()
+        finally:
+            # Make sure those are executed even if one of the device.destroy
+            # methods throws exeptions.
+            while len(self._cleanup_jobs):
+                job, args = self._cleanup_jobs.pop()
+                job(*args)
+
+    def snapshot(self):
+        """Creates a snapshot of the original source media of the Disk
+        instance.
         """
 
-        output("Examining source media `%s'..." % self.source, False)
+        self.out.output("Examining source media `%s' ..." % self.source, False)
         sourcedev = self.source
         mode = os.stat(self.source).st_mode
         if stat.S_ISDIR(mode):
-            success('looks like a directory')
-            return self._losetup(self._dir_to_disk())
+            self.out.success('looks like a directory')
+            return self._dir_to_disk()
         elif stat.S_ISREG(mode):
-            success('looks like an image file')
+            self.out.success('looks like an image file')
             sourcedev = self._losetup(self.source)
         elif not stat.S_ISBLK(mode):
-            raise ValueError("Invalid media source. Only block devices, "
-                            "regular files and directories are supported.")
+            raise FatalError("Invalid media source. Only block devices, "
+                             "regular files and directories are supported.")
         else:
-            success('looks like a block device')
+            self.out.success('looks like a block device')
 
         # Take a snapshot and return it to the user
-        output("Snapshotting media source...", False)
-        size = blockdev('--getsize', sourcedev)
-        cowfd, cow = tempfile.mkstemp()
+        self.out.output("Snapshotting media source...", False)
+        size = blockdev('--getsz', sourcedev)
+        cowfd, cow = tempfile.mkstemp(dir=self.tmp)
         os.close(cowfd)
         self._add_cleanup(os.unlink, cow)
-        # Create 1G cow sparse file
-        dd('if=/dev/null', 'of=%s' % cow, 'bs=1k', \
-                                        'seek=%d' % (1024 * 1024))
+        # Create cow sparse file
+        dd('if=/dev/null', 'of=%s' % cow, 'bs=512', 'seek=%d' % int(size))
         cowdev = self._losetup(cow)
 
         snapshot = uuid.uuid4().hex
         tablefd, table = tempfile.mkstemp()
         try:
-            os.write(tablefd, "0 %d snapshot %s %s n 8" % \
-                                        (int(size), sourcedev, cowdev))
+            os.write(tablefd, "0 %d snapshot %s %s n 8" %
+                              (int(size), sourcedev, cowdev))
             dmsetup('create', snapshot, table)
-            self._add_cleanup(dmsetup, 'remove', snapshot)
-            # Sometimes dmsetup remove fails with Device or resource busy,
-            # although everything is cleaned up and the snapshot is not
-            # used by anyone. Add a 2 seconds delay to be on the safe side.
-            self._add_cleanup(time.sleep, 2)
+            self._add_cleanup(try_fail_repeat, dmsetup, 'remove', snapshot)
 
         finally:
             os.unlink(table)
-        success('done')
-        new_device = DiskDevice("/dev/mapper/%s" % snapshot)
-        self._devices.append(new_device)
-        new_device.enable()
-        return new_device
-
-    def destroy_device(self, device):
-        """Destroys a DiskDevice instance previously created by
-        get_device method.
-        """
-        self._devices.remove(device)
-        device.destroy()
-
-
-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):
-        """Create a new DiskDevice."""
-
-        self.device = device
-        self.bootable = bootable
-        self.progress_bar = None
-
-        self.g = guestfs.GuestFS()
-        self.g.add_drive_opts(self.device, readonly=0)
-
-        #self.g.set_trace(1)
-        #self.g.set_verbose(1)
-
-        self.guestfs_enabled = False
-
-    def enable(self):
-        """Enable a newly created DiskDevice"""
-        self.progressbar = progress("Launching helper VM: ")
-        self.progressbar.next()
-        eh = self.g.set_event_callback(self.progress_callback,
-                                                    guestfs.EVENT_PROGRESS)
-        self.g.launch()
-        self.guestfs_enabled = True
-        self.g.delete_event_callback(eh)
-        if self.progressbar is not None:
-            self.progressbar.send(100)
-            self.progressbar = None
-
-        output('Inspecting Operating System...', False)
-        roots = self.g.inspect_os()
-        if len(roots) == 0:
-            raise FatalError("No operating system found")
-        if len(roots) > 1:
-            raise FatalError("Multiple operating systems found."
-                            "We only support images with one filesystem.")
-        self.root = roots[0]
-        self.ostype = self.g.inspect_get_type(self.root)
-        self.distro = self.g.inspect_get_distro(self.root)
-        success('found a %s system' % self.distro)
+        self.out.success('done')
+        return "/dev/mapper/%s" % snapshot
 
-    def destroy(self):
-        """Destroy this DiskDevice instance."""
+    def get_image(self, media):
+        """Returns a newly created Image instance."""
 
-        if self.guestfs_enabled:
-            self.g.umount_all()
-            self.g.sync()
+        image = Image(media, self.out)
+        self._images.append(image)
+        image.enable()
+        return image
 
-        # Close the guestfs handler if open
-        self.g.close()
-
-    def progress_callback(self, ev, eh, buf, array):
-        position = array[2]
-        total = array[3]
-
-        self.progressbar.send((position * 100) // total)
-
-        if position == total:
-            self.progressbar = None
-
-    def mount(self):
-        """Mount all disk partitions in a correct order."""
-
-        output("Mounting image...", False)
-        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
-        mps.sort(compare)
-        for mp, dev in mps:
-            try:
-                self.g.mount(dev, mp)
-            except RuntimeError as msg:
-                warn("%s (ignored)" % msg)
-        success("done")
-
-    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.
-        """
-        output("Shrinking image (this may take a while)...", False)
-
-        dev = self.g.part_to_dev(self.root)
-        parttype = self.g.part_get_parttype(dev)
-        if parttype != 'msdos':
-            raise FatalError("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 FatalError("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):
-            warn("Don't know how to resize %s partitions." % vfs_type)
-            return
-
-        self.g.e2fsck_f(part_dev)
-        self.g.resize2fs_M(part_dev)
-
-        out = self.g.tune2fs_l(part_dev)
-        block_size = int(
-            filter(lambda x: x[0] == 'Block size', out)[0][1])
-        block_cnt = int(
-            filter(lambda x: x[0] == 'Block count', out)[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)
-
-        new_size = (end + 1) * sector_size
-        success("new image size is %dMB" %
-                            ((new_size + 2 ** 20 - 1) // 2 ** 20))
-        return new_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).
+    def destroy_image(self, image):
+        """Destroys an Image instance previously created by get_image method.
         """
-        dev = self.g.part_to_dev(self.root)
-        last = self.g.part_list(dev)[-1]
-
-        return last['part_end'] + 1
-
-    def dump(self, outfile):
-        """Dumps the content of device into a file.
-
-        This method will only dump the actual payload, found by reading the
-        partition table. Empty space in the end of the device will be ignored.
-        """
-        blocksize = 2 ** 22  # 4MB
-        size = self.size()
-        progress_size = (size + 2 ** 20 - 1) // 2 ** 20  # in MB
-        progressbar = progress("Dumping image file: ", progress_size)
-
-        source = open(self.device, "r")
-        try:
-            dest = open(outfile, "w")
-            try:
-                left = size
-                offset = 0
-                progressbar.next()
-                while left > 0:
-                    length = min(left, blocksize)
-                    sent = sendfile(dest.fileno(), source.fileno(), offset,
-                                                                        length)
-                    offset += sent
-                    left -= sent
-                    for i in range((length + 2 ** 20 - 1) // 2 ** 20):
-                        progressbar.next()
-            finally:
-                dest.close()
-        finally:
-            source.close()
-
-        success('Image file %s was successfully created' % outfile)
+        self._images.remove(image)
+        image.destroy()
 
 # vim: set sta sts=4 shiftwidth=4 sw=4 et ai :