storage.py 8.1 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. @property
  85. def pool(self):
  86. '''Storage volume pool name.'''
  87. if self._pool is not None:
  88. return self._pool
  89. self._fetch_info()
  90. return str(self._info['pool'])
  91. @property
  92. def vid(self):
  93. '''Storage volume id, unique within given pool.'''
  94. if self._vid is not None:
  95. return self._vid
  96. self._fetch_info()
  97. return str(self._info['vid'])
  98. @property
  99. def size(self):
  100. '''Size of volume, in bytes.'''
  101. self._fetch_info(True)
  102. return int(self._info['size'])
  103. @property
  104. def usage(self):
  105. '''Used volume space, in bytes.'''
  106. self._fetch_info(True)
  107. return int(self._info['usage'])
  108. @property
  109. def rw(self):
  110. '''True if volume is read-write.'''
  111. self._fetch_info()
  112. return self._info['rw'] == 'True'
  113. @property
  114. def snap_on_start(self):
  115. '''Create a snapshot from source on VM start.'''
  116. self._fetch_info()
  117. return self._info['snap_on_start'] == 'True'
  118. @property
  119. def save_on_stop(self):
  120. '''Commit changes to original volume on VM stop.'''
  121. self._fetch_info()
  122. return self._info['save_on_stop'] == 'True'
  123. @property
  124. def source(self):
  125. '''Volume ID of source volume (for :py:attr:`snap_on_start`).
  126. If None, this volume itself will be used.
  127. '''
  128. self._fetch_info()
  129. if self._info['source']:
  130. return self._info['source']
  131. return None
  132. @property
  133. def internal(self):
  134. '''If `True` volume is hidden when qvm-block is used'''
  135. self._fetch_info()
  136. return self._info['internal'] == 'True'
  137. @property
  138. def revisions_to_keep(self):
  139. '''Number of revisions to keep around'''
  140. self._fetch_info()
  141. return int(self._info['revisions_to_keep'])
  142. def resize(self, size):
  143. '''Resize volume.
  144. Currently only extending is supported.
  145. :param int size: new size in bytes.
  146. '''
  147. self._qubesd_call('Resize', str(size).encode('ascii'))
  148. @property
  149. def revisions(self):
  150. ''' Returns iterable containing revision identifiers'''
  151. revisions = self._qubesd_call('ListSnapshots')
  152. return revisions.decode('ascii').splitlines()
  153. def revert(self, revision):
  154. ''' Revert volume to previous revision
  155. :param str revision: Revision identifier to revert to
  156. '''
  157. if not isinstance(revision, str):
  158. raise TypeError('revision must be a str')
  159. self._qubesd_call('Revert', revision.encode('ascii'))
  160. def import_data(self, stream):
  161. ''' Import volume data from a given file-like object.
  162. This function override existing volume content
  163. :param stream: file-like object, must support fileno()
  164. '''
  165. self._qubesd_call('Import', payload_stream=stream)
  166. class Pool(object):
  167. ''' A Pool is used to manage different kind of volumes (File
  168. based/LVM/Btrfs/...).
  169. '''
  170. def __init__(self, app, name=None):
  171. ''' Initialize storage pool wrapper
  172. :param app: Qubes() object
  173. :param name: name of the pool
  174. '''
  175. self.app = app
  176. self.name = name
  177. self._config = None
  178. def __str__(self):
  179. return self.name
  180. def __eq__(self, other):
  181. if isinstance(other, Pool):
  182. return self.name == other.name
  183. elif isinstance(other, str):
  184. return self.name == other
  185. return NotImplemented
  186. def __lt__(self, other):
  187. if isinstance(other, Pool):
  188. return self.name < other.name
  189. return NotImplemented
  190. @property
  191. def config(self):
  192. ''' Storage pool config '''
  193. if self._config is None:
  194. pool_info_data = self.app.qubesd_call(
  195. 'dom0', 'admin.pool.Info', self.name, None)
  196. pool_info_data = pool_info_data.decode('utf-8')
  197. assert pool_info_data.endswith('\n')
  198. pool_info_data = pool_info_data[:-1]
  199. self._config = dict(
  200. l.split('=', 1) for l in pool_info_data.splitlines())
  201. return self._config
  202. @property
  203. def driver(self):
  204. ''' Storage pool driver '''
  205. return self.config['driver']
  206. @property
  207. def volumes(self):
  208. ''' Volumes managed by this pool '''
  209. volumes_data = self.app.qubesd_call(
  210. 'dom0', 'admin.pool.volume.List', self.name, None)
  211. assert volumes_data.endswith(b'\n')
  212. volumes_data = volumes_data[:-1].decode('ascii')
  213. for vid in volumes_data.splitlines():
  214. yield Volume(self.app, self.name, vid)