storage.py 9.0 KB

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  1. # -*- encoding: utf8 -*-
  2. #
  3. # The Qubes OS Project, http://www.qubes-os.org
  4. #
  5. # Copyright (C) 2017 Marek Marczykowski-Górecki
  6. # <marmarek@invisiblethingslab.com>
  7. #
  8. # This program is free software; you can redistribute it and/or modify
  9. # it under the terms of the GNU Lesser General Public License as published by
  10. # the Free Software Foundation; either version 2.1 of the License, or
  11. # (at your option) any later version.
  12. #
  13. # This program is distributed in the hope that it will be useful,
  14. # but WITHOUT ANY WARRANTY; without even the implied warranty of
  15. # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16. # GNU Lesser General Public License for more details.
  17. #
  18. # You should have received a copy of the GNU Lesser General Public License along
  19. # with this program; if not, see <http://www.gnu.org/licenses/>.
  20. '''Storage subsystem.'''
  21. class Volume(object):
  22. '''Storage volume.'''
  23. def __init__(self, app, pool=None, vid=None, vm=None, vm_name=None):
  24. '''Construct a Volume object.
  25. Volume may be identified using pool+vid, or vm+vm_name. Either of
  26. those argument pairs must be given.
  27. :param Qubes app: application instance
  28. :param str pool: pool name
  29. :param str vid: volume id (within pool)
  30. :param str vm: owner VM name
  31. :param str vm_name: name within owning VM (like 'private', 'root' etc)
  32. '''
  33. self.app = app
  34. if pool is None and vm is None:
  35. raise ValueError('Either pool or vm must be given')
  36. if pool is not None and vid is None:
  37. raise ValueError('If pool is given, vid must be too.')
  38. if vm is not None and vm_name is None:
  39. raise ValueError('If vm is given, vm_name must be too.')
  40. self._pool = pool
  41. self._vid = vid
  42. self._vm = vm
  43. self._vm_name = vm_name
  44. self._info = None
  45. def _qubesd_call(self, func_name, payload=None, payload_stream=None):
  46. '''Make a call to qubesd regarding this volume
  47. :param str func_name: API function name, like `Info` or `Resize`
  48. :param bytes payload: Payload to send.
  49. :param file payload_stream: Stream to pipe payload from. Only one of
  50. `payload` and `payload_stream` can be used.
  51. '''
  52. if self._vm is not None:
  53. method = 'admin.vm.volume.' + func_name
  54. dest = self._vm
  55. arg = self._vm_name
  56. else:
  57. if payload_stream:
  58. raise NotImplementedError(
  59. 'payload_stream not implemented for '
  60. 'admin.pool.volume.* calls')
  61. method = 'admin.pool.volume.' + func_name
  62. dest = 'dom0'
  63. arg = self._pool
  64. if payload is not None:
  65. payload = self._vid.encode('ascii') + b' ' + payload
  66. else:
  67. payload = self._vid.encode('ascii')
  68. return self.app.qubesd_call(dest, method, arg, payload=payload,
  69. payload_stream=payload_stream)
  70. def _fetch_info(self, force=True):
  71. '''Fetch volume properties
  72. Populate self._info dict
  73. :param bool force: refresh self._info, even if already populated.
  74. '''
  75. if not force and self._info is not None:
  76. return
  77. info = self._qubesd_call('Info')
  78. info = info.decode('ascii')
  79. self._info = dict([line.split('=', 1) for line in info.splitlines()])
  80. def __eq__(self, other):
  81. if isinstance(other, Volume):
  82. return self.pool == other.pool and self.vid == other.vid
  83. return NotImplemented
  84. def __lt__(self, other):
  85. # pylint: disable=protected-access
  86. if isinstance(other, Volume):
  87. if self._vm and other._vm:
  88. return (self._vm, self._vm_name) < (other._vm, other._vm_name)
  89. elif self._vid and other._vid:
  90. return (self._pool, self._vid) < (other._pool, other._vid)
  91. return NotImplemented
  92. @property
  93. def name(self):
  94. '''per-VM volume name, if available'''
  95. return self._vm_name
  96. @property
  97. def pool(self):
  98. '''Storage volume pool name.'''
  99. if self._pool is not None:
  100. return self._pool
  101. self._fetch_info()
  102. return str(self._info['pool'])
  103. @property
  104. def vid(self):
  105. '''Storage volume id, unique within given pool.'''
  106. if self._vid is not None:
  107. return self._vid
  108. self._fetch_info()
  109. return str(self._info['vid'])
  110. @property
  111. def size(self):
  112. '''Size of volume, in bytes.'''
  113. self._fetch_info(True)
  114. return int(self._info['size'])
  115. @property
  116. def usage(self):
  117. '''Used volume space, in bytes.'''
  118. self._fetch_info(True)
  119. return int(self._info['usage'])
  120. @property
  121. def rw(self):
  122. '''True if volume is read-write.'''
  123. self._fetch_info()
  124. return self._info['rw'] == 'True'
  125. @property
  126. def snap_on_start(self):
  127. '''Create a snapshot from source on VM start.'''
  128. self._fetch_info()
  129. return self._info['snap_on_start'] == 'True'
  130. @property
  131. def save_on_stop(self):
  132. '''Commit changes to original volume on VM stop.'''
  133. self._fetch_info()
  134. return self._info['save_on_stop'] == 'True'
  135. @property
  136. def source(self):
  137. '''Volume ID of source volume (for :py:attr:`snap_on_start`).
  138. If None, this volume itself will be used.
  139. '''
  140. self._fetch_info()
  141. if self._info['source']:
  142. return self._info['source']
  143. return None
  144. @property
  145. def revisions_to_keep(self):
  146. '''Number of revisions to keep around'''
  147. self._fetch_info()
  148. return int(self._info['revisions_to_keep'])
  149. def resize(self, size):
  150. '''Resize volume.
  151. Currently only extending is supported.
  152. :param int size: new size in bytes.
  153. '''
  154. self._qubesd_call('Resize', str(size).encode('ascii'))
  155. @property
  156. def revisions(self):
  157. ''' Returns iterable containing revision identifiers'''
  158. revisions = self._qubesd_call('ListSnapshots')
  159. return revisions.decode('ascii').splitlines()
  160. def revert(self, revision):
  161. ''' Revert volume to previous revision
  162. :param str revision: Revision identifier to revert to
  163. '''
  164. if not isinstance(revision, str):
  165. raise TypeError('revision must be a str')
  166. self._qubesd_call('Revert', revision.encode('ascii'))
  167. def import_data(self, stream):
  168. ''' Import volume data from a given file-like object.
  169. This function override existing volume content
  170. :param stream: file-like object, must support fileno()
  171. '''
  172. self._qubesd_call('Import', payload_stream=stream)
  173. def clone(self, source):
  174. ''' Clone data from sane volume of another VM.
  175. This function override existing volume content.
  176. This operation is implemented for VM volumes - those in vm.volumes
  177. collection (not pool.volumes).
  178. :param source: source volume object
  179. '''
  180. # pylint: disable=protected-access
  181. # get a token from source volume
  182. token = source._qubesd_call('CloneFrom')
  183. # and use it to actually clone volume data
  184. self._qubesd_call('CloneTo', payload=token)
  185. class Pool(object):
  186. ''' A Pool is used to manage different kind of volumes (File
  187. based/LVM/Btrfs/...).
  188. '''
  189. def __init__(self, app, name=None):
  190. ''' Initialize storage pool wrapper
  191. :param app: Qubes() object
  192. :param name: name of the pool
  193. '''
  194. self.app = app
  195. self.name = name
  196. self._config = None
  197. def __str__(self):
  198. return self.name
  199. def __eq__(self, other):
  200. if isinstance(other, Pool):
  201. return self.name == other.name
  202. elif isinstance(other, str):
  203. return self.name == other
  204. return NotImplemented
  205. def __lt__(self, other):
  206. if isinstance(other, Pool):
  207. return self.name < other.name
  208. return NotImplemented
  209. @property
  210. def config(self):
  211. ''' Storage pool config '''
  212. if self._config is None:
  213. pool_info_data = self.app.qubesd_call(
  214. 'dom0', 'admin.pool.Info', self.name, None)
  215. pool_info_data = pool_info_data.decode('utf-8')
  216. assert pool_info_data.endswith('\n')
  217. pool_info_data = pool_info_data[:-1]
  218. self._config = dict(
  219. l.split('=', 1) for l in pool_info_data.splitlines())
  220. return self._config
  221. @property
  222. def driver(self):
  223. ''' Storage pool driver '''
  224. return self.config['driver']
  225. @property
  226. def volumes(self):
  227. ''' Volumes managed by this pool '''
  228. volumes_data = self.app.qubesd_call(
  229. 'dom0', 'admin.pool.volume.List', self.name, None)
  230. assert volumes_data.endswith(b'\n')
  231. volumes_data = volumes_data[:-1].decode('ascii')
  232. for vid in volumes_data.splitlines():
  233. yield Volume(self.app, self.name, vid)