VDI images working now

*Helpful error messages included

base/fs/nopartitions.py

@@ -6,6 +6,7 @@ class NoPartitions(object):
 	def __init__(self, data):
 		root = data['root']
 		self.root = SinglePartition(root['size'], root['filesystem'])
+		self.partitions = [self.root]
 		self.mount_points = [('/', self.root)]
 
 	def get_total_size(self):

common/fs/__init__.py

@@ -1,11 +1,16 @@
 
 
-def get_major_minor_dev_num(device_name):
+def get_partitions():
 	import re
-	regexp = re.compile('^ *(?P<major>\d+) *(?P<minor>\d+) *(?P<num_blks>\d+) {device_name}$'
-	                    .format(device_name=device_name))
-	with open('/proc/partitions') as partitions:
+	regexp = re.compile('^ *(?P<major>\d+) *(?P<minor>\d+) *(?P<num_blks>\d+) (?P<dev_name>\S+)$')
+	matches = {}
+	path = '/proc/partitions'
+	with open(path) as partitions:
+		next(partitions)
+		next(partitions)
 		for line in partitions:
 			match = regexp.match(line)
-			if match is not None:
-				return match.group('major'), match.group('minor')
+			if match is None:
+				raise RuntimeError('Unable to parse {line} in {path}'.format(line=line, path=path))
+			matches[match.group('dev_name')] = match.groupdict()
+	return matches

common/fs/loopbackvolume.py

@@ -49,15 +49,17 @@ class LoopbackVolume(Volume):
 
 	def _link_dm_node(self, e):
 		import os.path
+		from . import get_partitions
+		proc_partitions = get_partitions()
 		loop_device_name = os.path.basename(self.loop_device_path)
-		from . import get_major_minor_dev_num
-		major, minor = get_major_minor_dev_num(loop_device_name)
+		loop_device_partition = proc_partitions[loop_device_name]
+
 		sectors = self.size*1024*1024/512
 		table = ('{log_start_sec} {sectors} linear {major}:{minor} {start_sec}'
 		         .format(log_start_sec=0,
 		                 sectors=sectors,
-		                 major=major,
-		                 minor=minor,
+		                 major=loop_device_partition['major'],
+		                 minor=loop_device_partition['minor'],
 		                 start_sec=0))
 		import string
 		import os.path

common/tasks/filesystem.py

@@ -64,15 +64,15 @@ class MountBoot(Task):
 
 
 class CreateBootMountDir(Task):
-	description = 'Creating mountpoint boot partition'
+	description = 'Creating mountpoint for the boot partition'
 	phase = phases.volume_mounting
 	after = [MountRoot]
 	before = [MountBoot]
 
 	def run(self, info):
 		import os
-		info.boot = os.path.join(info.root, 'boot')
-		os.makedirs()
+		boot_dir = os.path.join(info.root, 'boot')
+		os.makedirs(boot_dir)
 
 
 class MountSpecials(Task):

providers/virtualbox/__init__.py

@@ -91,7 +91,9 @@ def tasks(tasklist, manifest):
 			break
 
 	if 'boot' in manifest.volume['partitions']:
-		tasklist.add(filesystem.MountBoot(), filesystem.UnmountBoot())
+		tasklist.add(filesystem.CreateBootMountDir(),
+		             filesystem.MountBoot(),
+		             filesystem.UnmountBoot())
 
 
 def rollback_tasks(tasklist, tasks_completed, manifest):
@@ -105,7 +107,7 @@ def rollback_tasks(tasklist, tasks_completed, manifest):
 	counter_task(filesystem.CreateMountDir, filesystem.DeleteMountDir)
 	counter_task(partitioning.MapPartitions, partitioning.UnmapPartitions)
 	counter_task(filesystem.MountRoot, filesystem.UnmountRoot)
-	counter_task(filesystem.MountSpecials, filesystem.UnmountSpecials)
 	counter_task(filesystem.MountBoot, filesystem.UnmountBoot)
+	counter_task(filesystem.MountSpecials, filesystem.UnmountSpecials)
 	counter_task(volume_tasks.Attach, volume_tasks.Detach)
 	counter_task(workspace.CreateWorkspace, workspace.DeleteWorkspace)

providers/virtualbox/volume.py

@@ -1,5 +1,7 @@
 from common.fs.loopbackvolume import LoopbackVolume
+from base.fs.exceptions import VolumeError
 from common.tools import log_check_call
+from common.fs import get_partitions
 
 
 class VirtualBoxVolume(LoopbackVolume):
@@ -9,3 +11,57 @@ class VirtualBoxVolume(LoopbackVolume):
 	def _create(self, e):
 		self.image_path = e.image_path
 		log_check_call(['/usr/bin/qemu-img', 'create', '-f', 'vdi', self.image_path, str(self.size) + 'M'])
+
+	def _attach(self, e):
+		num_partitions = len(self.partition_map.partitions)
+		if not self._module_loaded('nbd'):
+			msg = ('The kernel module `nbd\' must be loaded '
+			       '(`modprobe nbd max_part={num_partitions}\') to attach .vdi images'
+			       .format(num_partitions=num_partitions))
+			raise VolumeError(msg)
+		nbd_max_part = int(self._module_param('nbd', 'max_part'))
+		if nbd_max_part < num_partitions:
+			msg = ('The kernel module `nbd\' was loaded with the max_part '
+			       'parameter set to {max_part}, which is below '
+			       'the amount of partitions for this volume ({num_partitions}). '
+			       'Reload the nbd kernel module with max_part set to at least {num_partitions} '
+			       '(`rmmod nbd; modprobe nbd max_part={num_partitions}\').'
+			       .format(max_part=nbd_max_part, num_partitions=num_partitions))
+			raise VolumeError(msg)
+		self.loop_device_path = self._find_free_nbd_device()
+		log_check_call(['/usr/bin/qemu-nbd', '--connect', self.loop_device_path, self.image_path])
+		self.device_path = self.loop_device_path
+
+	def _detach(self, e):
+		log_check_call(['/usr/bin/qemu-nbd', '--disconnect', self.loop_device_path])
+		del self.loop_device_path
+		del self.device_path
+
+	def _module_loaded(self, module):
+		import re
+		regexp = re.compile('^{module} +'.format(module=module))
+		with open('/proc/modules') as loaded_modules:
+			for line in loaded_modules:
+				match = regexp.match(line)
+				if match is not None:
+					return True
+		return False
+
+	def _module_param(self, module, param):
+		import os.path
+		param_path = os.path.join('/sys/module', module, 'parameters', param)
+		with open(param_path) as param:
+			return param.read().strip()
+
+	# From http://lists.gnu.org/archive/html/qemu-devel/2011-11/msg02201.html
+	# Apparently it's not in the current qemu-nbd shipped with wheezy
+	def _is_nbd_used(self, device_name):
+		return device_name in get_partitions()
+
+	def _find_free_nbd_device(self):
+		import os.path
+		for i in xrange(0, 15):
+			device_name = 'nbd' + str(i)
+			if not self._is_nbd_used(device_name):
+				return os.path.join('/dev', device_name)
+		raise VolumeError('Unable to find free nbd device.')