Package CedarBackup2 :: Package writers :: Module dvdwriter
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Source Code for Module CedarBackup2.writers.dvdwriter

  1  # -*- coding: iso-8859-1 -*- 
  2  # vim: set ft=python ts=3 sw=3 expandtab: 
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  4  # 
  5  #              C E D A R 
  6  #          S O L U T I O N S       "Software done right." 
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 10  # 
 11  # Copyright (c) 2007-2008,2010 Kenneth J. Pronovici. 
 12  # All rights reserved. 
 13  # 
 14  # This program is free software; you can redistribute it and/or 
 15  # modify it under the terms of the GNU General Public License, 
 16  # Version 2, as published by the Free Software Foundation. 
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 18  # This program is distributed in the hope that it will be useful, 
 19  # but WITHOUT ANY WARRANTY; without even the implied warranty of 
 20  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 21  # 
 22  # Copies of the GNU General Public License are available from 
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 25  # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
 26  # 
 27  # Author   : Kenneth J. Pronovici <pronovic@ieee.org> 
 28  # Language : Python (>= 2.5) 
 29  # Project  : Cedar Backup, release 2 
 30  # Revision : $Id: dvdwriter.py 1041 2013-05-10 02:05:13Z pronovic $ 
 31  # Purpose  : Provides functionality related to DVD writer devices. 
 32  # 
 33  # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
 34   
 35  ######################################################################## 
 36  # Module documentation 
 37  ######################################################################## 
 38   
 39  """ 
 40  Provides functionality related to DVD writer devices. 
 41   
 42  @sort: MediaDefinition, DvdWriter, MEDIA_DVDPLUSR, MEDIA_DVDPLUSRW 
 43   
 44  @var MEDIA_DVDPLUSR: Constant representing DVD+R media. 
 45  @var MEDIA_DVDPLUSRW: Constant representing DVD+RW media. 
 46   
 47  @author: Kenneth J. Pronovici <pronovic@ieee.org> 
 48  @author: Dmitry Rutsky <rutsky@inbox.ru> 
 49  """ 
 50   
 51  ######################################################################## 
 52  # Imported modules 
 53  ######################################################################## 
 54   
 55  # System modules 
 56  import os 
 57  import re 
 58  import logging 
 59  import tempfile 
 60  import time 
 61   
 62  # Cedar Backup modules 
 63  from CedarBackup2.writers.util import IsoImage 
 64  from CedarBackup2.util import resolveCommand, executeCommand 
 65  from CedarBackup2.util import convertSize, displayBytes, encodePath 
 66  from CedarBackup2.util import UNIT_SECTORS, UNIT_BYTES, UNIT_GBYTES 
 67  from CedarBackup2.writers.util import validateDevice, validateDriveSpeed 
 68   
 69   
 70  ######################################################################## 
 71  # Module-wide constants and variables 
 72  ######################################################################## 
 73   
 74  logger = logging.getLogger("CedarBackup2.log.writers.dvdwriter") 
 75   
 76  MEDIA_DVDPLUSR  = 1 
 77  MEDIA_DVDPLUSRW = 2 
 78   
 79  GROWISOFS_COMMAND = [ "growisofs", ] 
 80  EJECT_COMMAND     = [ "eject", ] 
81 82 83 ######################################################################## 84 # MediaDefinition class definition 85 ######################################################################## 86 87 -class MediaDefinition(object):
88 89 """ 90 Class encapsulating information about DVD media definitions. 91 92 The following media types are accepted: 93 94 - C{MEDIA_DVDPLUSR}: DVD+R media (4.4 GB capacity) 95 - C{MEDIA_DVDPLUSRW}: DVD+RW media (4.4 GB capacity) 96 97 Note that the capacity attribute returns capacity in terms of ISO sectors 98 (C{util.ISO_SECTOR_SIZE)}. This is for compatibility with the CD writer 99 functionality. 100 101 The capacities are 4.4 GB because Cedar Backup deals in "true" gigabytes 102 of 1024*1024*1024 bytes per gigabyte. 103 104 @sort: __init__, mediaType, rewritable, capacity 105 """ 106
107 - def __init__(self, mediaType):
108 """ 109 Creates a media definition for the indicated media type. 110 @param mediaType: Type of the media, as discussed above. 111 @raise ValueError: If the media type is unknown or unsupported. 112 """ 113 self._mediaType = None 114 self._rewritable = False 115 self._capacity = 0.0 116 self._setValues(mediaType)
117
118 - def _setValues(self, mediaType):
119 """ 120 Sets values based on media type. 121 @param mediaType: Type of the media, as discussed above. 122 @raise ValueError: If the media type is unknown or unsupported. 123 """ 124 if mediaType not in [MEDIA_DVDPLUSR, MEDIA_DVDPLUSRW, ]: 125 raise ValueError("Invalid media type %d." % mediaType) 126 self._mediaType = mediaType 127 if self._mediaType == MEDIA_DVDPLUSR: 128 self._rewritable = False 129 self._capacity = convertSize(4.4, UNIT_GBYTES, UNIT_SECTORS) # 4.4 "true" GB = 4.7 "marketing" GB 130 elif self._mediaType == MEDIA_DVDPLUSRW: 131 self._rewritable = True 132 self._capacity = convertSize(4.4, UNIT_GBYTES, UNIT_SECTORS) # 4.4 "true" GB = 4.7 "marketing" GB
133
134 - def _getMediaType(self):
135 """ 136 Property target used to get the media type value. 137 """ 138 return self._mediaType
139
140 - def _getRewritable(self):
141 """ 142 Property target used to get the rewritable flag value. 143 """ 144 return self._rewritable
145
146 - def _getCapacity(self):
147 """ 148 Property target used to get the capacity value. 149 """ 150 return self._capacity
151 152 mediaType = property(_getMediaType, None, None, doc="Configured media type.") 153 rewritable = property(_getRewritable, None, None, doc="Boolean indicating whether the media is rewritable.") 154 capacity = property(_getCapacity, None, None, doc="Total capacity of media in 2048-byte sectors.")
155
156 157 ######################################################################## 158 # MediaCapacity class definition 159 ######################################################################## 160 161 -class MediaCapacity(object):
162 163 """ 164 Class encapsulating information about DVD media capacity. 165 166 Space used and space available do not include any information about media 167 lead-in or other overhead. 168 169 @sort: __init__, bytesUsed, bytesAvailable, totalCapacity, utilized 170 """ 171
172 - def __init__(self, bytesUsed, bytesAvailable):
173 """ 174 Initializes a capacity object. 175 @raise ValueError: If the bytes used and available values are not floats. 176 """ 177 self._bytesUsed = float(bytesUsed) 178 self._bytesAvailable = float(bytesAvailable)
179
180 - def __str__(self):
181 """ 182 Informal string representation for class instance. 183 """ 184 return "utilized %s of %s (%.2f%%)" % (displayBytes(self.bytesUsed), displayBytes(self.totalCapacity), self.utilized)
185
186 - def _getBytesUsed(self):
187 """ 188 Property target used to get the bytes-used value. 189 """ 190 return self._bytesUsed
191
192 - def _getBytesAvailable(self):
193 """ 194 Property target available to get the bytes-available value. 195 """ 196 return self._bytesAvailable
197
198 - def _getTotalCapacity(self):
199 """ 200 Property target to get the total capacity (used + available). 201 """ 202 return self.bytesUsed + self.bytesAvailable
203
204 - def _getUtilized(self):
205 """ 206 Property target to get the percent of capacity which is utilized. 207 """ 208 if self.bytesAvailable <= 0.0: 209 return 100.0 210 elif self.bytesUsed <= 0.0: 211 return 0.0 212 return (self.bytesUsed / self.totalCapacity) * 100.0
213 214 bytesUsed = property(_getBytesUsed, None, None, doc="Space used on disc, in bytes.") 215 bytesAvailable = property(_getBytesAvailable, None, None, doc="Space available on disc, in bytes.") 216 totalCapacity = property(_getTotalCapacity, None, None, doc="Total capacity of the disc, in bytes.") 217 utilized = property(_getUtilized, None, None, "Percentage of the total capacity which is utilized.")
218
219 220 ######################################################################## 221 # _ImageProperties class definition 222 ######################################################################## 223 224 -class _ImageProperties(object):
225 """ 226 Simple value object to hold image properties for C{DvdWriter}. 227 """
228 - def __init__(self):
229 self.newDisc = False 230 self.tmpdir = None 231 self.mediaLabel = None 232 self.entries = None # dict mapping path to graft point
233
234 235 ######################################################################## 236 # DvdWriter class definition 237 ######################################################################## 238 239 -class DvdWriter(object):
240 241 ###################### 242 # Class documentation 243 ###################### 244 245 """ 246 Class representing a device that knows how to write some kinds of DVD media. 247 248 Summary 249 ======= 250 251 This is a class representing a device that knows how to write some kinds 252 of DVD media. It provides common operations for the device, such as 253 ejecting the media and writing data to the media. 254 255 This class is implemented in terms of the C{eject} and C{growisofs} 256 utilities, all of which should be available on most UN*X platforms. 257 258 Image Writer Interface 259 ====================== 260 261 The following methods make up the "image writer" interface shared 262 with other kinds of writers:: 263 264 __init__ 265 initializeImage() 266 addImageEntry() 267 writeImage() 268 setImageNewDisc() 269 retrieveCapacity() 270 getEstimatedImageSize() 271 272 Only these methods will be used by other Cedar Backup functionality 273 that expects a compatible image writer. 274 275 The media attribute is also assumed to be available. 276 277 Unlike the C{CdWriter}, the C{DvdWriter} can only operate in terms of 278 filesystem devices, not SCSI devices. So, although the constructor 279 interface accepts a SCSI device parameter for the sake of compatibility, 280 it's not used. 281 282 Media Types 283 =========== 284 285 This class knows how to write to DVD+R and DVD+RW media, represented 286 by the following constants: 287 288 - C{MEDIA_DVDPLUSR}: DVD+R media (4.4 GB capacity) 289 - C{MEDIA_DVDPLUSRW}: DVD+RW media (4.4 GB capacity) 290 291 The difference is that DVD+RW media can be rewritten, while DVD+R media 292 cannot be (although at present, C{DvdWriter} does not really 293 differentiate between rewritable and non-rewritable media). 294 295 The capacities are 4.4 GB because Cedar Backup deals in "true" gigabytes 296 of 1024*1024*1024 bytes per gigabyte. 297 298 The underlying C{growisofs} utility does support other kinds of media 299 (including DVD-R, DVD-RW and BlueRay) which work somewhat differently 300 than standard DVD+R and DVD+RW media. I don't support these other kinds 301 of media because I haven't had any opportunity to work with them. The 302 same goes for dual-layer media of any type. 303 304 Device Attributes vs. Media Attributes 305 ====================================== 306 307 As with the cdwriter functionality, a given dvdwriter instance has two 308 different kinds of attributes associated with it. I call these device 309 attributes and media attributes. 310 311 Device attributes are things which can be determined without looking at 312 the media. Media attributes are attributes which vary depending on the 313 state of the media. In general, device attributes are available via 314 instance variables and are constant over the life of an object, while 315 media attributes can be retrieved through method calls. 316 317 Compared to cdwriters, dvdwriters have very few attributes. This is due 318 to differences between the way C{growisofs} works relative to 319 C{cdrecord}. 320 321 Media Capacity 322 ============== 323 324 One major difference between the C{cdrecord}/C{mkisofs} utilities used by 325 the cdwriter class and the C{growisofs} utility used here is that the 326 process of estimating remaining capacity and image size is more 327 straightforward with C{cdrecord}/C{mkisofs} than with C{growisofs}. 328 329 In this class, remaining capacity is calculated by asking doing a dry run 330 of C{growisofs} and grabbing some information from the output of that 331 command. Image size is estimated by asking the C{IsoImage} class for an 332 estimate and then adding on a "fudge factor" determined through 333 experimentation. 334 335 Testing 336 ======= 337 338 It's rather difficult to test this code in an automated fashion, even if 339 you have access to a physical DVD writer drive. It's even more difficult 340 to test it if you are running on some build daemon (think of a Debian 341 autobuilder) which can't be expected to have any hardware or any media 342 that you could write to. 343 344 Because of this, some of the implementation below is in terms of static 345 methods that are supposed to take defined actions based on their 346 arguments. Public methods are then implemented in terms of a series of 347 calls to simplistic static methods. This way, we can test as much as 348 possible of the "difficult" functionality via testing the static methods, 349 while hoping that if the static methods are called appropriately, things 350 will work properly. It's not perfect, but it's much better than no 351 testing at all. 352 353 @sort: __init__, isRewritable, retrieveCapacity, openTray, closeTray, refreshMedia, 354 initializeImage, addImageEntry, writeImage, setImageNewDisc, getEstimatedImageSize, 355 _writeImage, _getEstimatedImageSize, _searchForOverburn, _buildWriteArgs, 356 device, scsiId, hardwareId, driveSpeed, media, deviceHasTray, deviceCanEject 357 """ 358 359 ############## 360 # Constructor 361 ############## 362
363 - def __init__(self, device, scsiId=None, driveSpeed=None, 364 mediaType=MEDIA_DVDPLUSRW, noEject=False, 365 refreshMediaDelay=0, ejectDelay=0, unittest=False):
366 """ 367 Initializes a DVD writer object. 368 369 Since C{growisofs} can only address devices using the device path (i.e. 370 C{/dev/dvd}), the hardware id will always be set based on the device. If 371 passed in, it will be saved for reference purposes only. 372 373 We have no way to query the device to ask whether it has a tray or can be 374 safely opened and closed. So, the C{noEject} flag is used to set these 375 values. If C{noEject=False}, then we assume a tray exists and open/close 376 is safe. If C{noEject=True}, then we assume that there is no tray and 377 open/close is not safe. 378 379 @note: The C{unittest} parameter should never be set to C{True} 380 outside of Cedar Backup code. It is intended for use in unit testing 381 Cedar Backup internals and has no other sensible purpose. 382 383 @param device: Filesystem device associated with this writer. 384 @type device: Absolute path to a filesystem device, i.e. C{/dev/dvd} 385 386 @param scsiId: SCSI id for the device (optional, for reference only). 387 @type scsiId: If provided, SCSI id in the form C{[<method>:]scsibus,target,lun} 388 389 @param driveSpeed: Speed at which the drive writes. 390 @type driveSpeed: Use C{2} for 2x device, etc. or C{None} to use device default. 391 392 @param mediaType: Type of the media that is assumed to be in the drive. 393 @type mediaType: One of the valid media type as discussed above. 394 395 @param noEject: Tells Cedar Backup that the device cannot safely be ejected 396 @type noEject: Boolean true/false 397 398 @param refreshMediaDelay: Refresh media delay to use, if any 399 @type refreshMediaDelay: Number of seconds, an integer >= 0 400 401 @param ejectDelay: Eject delay to use, if any 402 @type ejectDelay: Number of seconds, an integer >= 0 403 404 @param unittest: Turns off certain validations, for use in unit testing. 405 @type unittest: Boolean true/false 406 407 @raise ValueError: If the device is not valid for some reason. 408 @raise ValueError: If the SCSI id is not in a valid form. 409 @raise ValueError: If the drive speed is not an integer >= 1. 410 """ 411 if scsiId is not None: 412 logger.warn("SCSI id [%s] will be ignored by DvdWriter." % scsiId) 413 self._image = None # optionally filled in by initializeImage() 414 self._device = validateDevice(device, unittest) 415 self._scsiId = scsiId # not validated, because it's just for reference 416 self._driveSpeed = validateDriveSpeed(driveSpeed) 417 self._media = MediaDefinition(mediaType) 418 self._refreshMediaDelay = refreshMediaDelay 419 self._ejectDelay = ejectDelay 420 if noEject: 421 self._deviceHasTray = False 422 self._deviceCanEject = False 423 else: 424 self._deviceHasTray = True # just assume 425 self._deviceCanEject = True # just assume
426 427 428 ############# 429 # Properties 430 ############# 431
432 - def _getDevice(self):
433 """ 434 Property target used to get the device value. 435 """ 436 return self._device
437
438 - def _getScsiId(self):
439 """ 440 Property target used to get the SCSI id value. 441 """ 442 return self._scsiId
443
444 - def _getHardwareId(self):
445 """ 446 Property target used to get the hardware id value. 447 """ 448 return self._device
449
450 - def _getDriveSpeed(self):
451 """ 452 Property target used to get the drive speed. 453 """ 454 return self._driveSpeed
455
456 - def _getMedia(self):
457 """ 458 Property target used to get the media description. 459 """ 460 return self._media
461
462 - def _getDeviceHasTray(self):
463 """ 464 Property target used to get the device-has-tray flag. 465 """ 466 return self._deviceHasTray
467
468 - def _getDeviceCanEject(self):
469 """ 470 Property target used to get the device-can-eject flag. 471 """ 472 return self._deviceCanEject
473
474 - def _getRefreshMediaDelay(self):
475 """ 476 Property target used to get the configured refresh media delay, in seconds. 477 """ 478 return self._refreshMediaDelay
479
480 - def _getEjectDelay(self):
481 """ 482 Property target used to get the configured eject delay, in seconds. 483 """ 484 return self._ejectDelay
485 486 device = property(_getDevice, None, None, doc="Filesystem device name for this writer.") 487 scsiId = property(_getScsiId, None, None, doc="SCSI id for the device (saved for reference only).") 488 hardwareId = property(_getHardwareId, None, None, doc="Hardware id for this writer (always the device path).") 489 driveSpeed = property(_getDriveSpeed, None, None, doc="Speed at which the drive writes.") 490 media = property(_getMedia, None, None, doc="Definition of media that is expected to be in the device.") 491 deviceHasTray = property(_getDeviceHasTray, None, None, doc="Indicates whether the device has a media tray.") 492 deviceCanEject = property(_getDeviceCanEject, None, None, doc="Indicates whether the device supports ejecting its media.") 493 refreshMediaDelay = property(_getRefreshMediaDelay, None, None, doc="Refresh media delay, in seconds.") 494 ejectDelay = property(_getEjectDelay, None, None, doc="Eject delay, in seconds.") 495 496 497 ################################################# 498 # Methods related to device and media attributes 499 ################################################# 500
501 - def isRewritable(self):
502 """Indicates whether the media is rewritable per configuration.""" 503 return self._media.rewritable
504
505 - def retrieveCapacity(self, entireDisc=False):
506 """ 507 Retrieves capacity for the current media in terms of a C{MediaCapacity} 508 object. 509 510 If C{entireDisc} is passed in as C{True}, the capacity will be for the 511 entire disc, as if it were to be rewritten from scratch. The same will 512 happen if the disc can't be read for some reason. Otherwise, the capacity 513 will be calculated by subtracting the sectors currently used on the disc, 514 as reported by C{growisofs} itself. 515 516 @param entireDisc: Indicates whether to return capacity for entire disc. 517 @type entireDisc: Boolean true/false 518 519 @return: C{MediaCapacity} object describing the capacity of the media. 520 521 @raise ValueError: If there is a problem parsing the C{growisofs} output 522 @raise IOError: If the media could not be read for some reason. 523 """ 524 sectorsUsed = 0 525 if not entireDisc: 526 sectorsUsed = self._retrieveSectorsUsed() 527 sectorsAvailable = self._media.capacity - sectorsUsed # both are in sectors 528 bytesUsed = convertSize(sectorsUsed, UNIT_SECTORS, UNIT_BYTES) 529 bytesAvailable = convertSize(sectorsAvailable, UNIT_SECTORS, UNIT_BYTES) 530 return MediaCapacity(bytesUsed, bytesAvailable)
531 532 533 ####################################################### 534 # Methods used for working with the internal ISO image 535 ####################################################### 536
537 - def initializeImage(self, newDisc, tmpdir, mediaLabel=None):
538 """ 539 Initializes the writer's associated ISO image. 540 541 This method initializes the C{image} instance variable so that the caller 542 can use the C{addImageEntry} method. Once entries have been added, the 543 C{writeImage} method can be called with no arguments. 544 545 @param newDisc: Indicates whether the disc should be re-initialized 546 @type newDisc: Boolean true/false 547 548 @param tmpdir: Temporary directory to use if needed 549 @type tmpdir: String representing a directory path on disk 550 551 @param mediaLabel: Media label to be applied to the image, if any 552 @type mediaLabel: String, no more than 25 characters long 553 """ 554 self._image = _ImageProperties() 555 self._image.newDisc = newDisc 556 self._image.tmpdir = encodePath(tmpdir) 557 self._image.mediaLabel = mediaLabel 558 self._image.entries = {} # mapping from path to graft point (if any)
559
560 - def addImageEntry(self, path, graftPoint):
561 """ 562 Adds a filepath entry to the writer's associated ISO image. 563 564 The contents of the filepath -- but not the path itself -- will be added 565 to the image at the indicated graft point. If you don't want to use a 566 graft point, just pass C{None}. 567 568 @note: Before calling this method, you must call L{initializeImage}. 569 570 @param path: File or directory to be added to the image 571 @type path: String representing a path on disk 572 573 @param graftPoint: Graft point to be used when adding this entry 574 @type graftPoint: String representing a graft point path, as described above 575 576 @raise ValueError: If initializeImage() was not previously called 577 @raise ValueError: If the path is not a valid file or directory 578 """ 579 if self._image is None: 580 raise ValueError("Must call initializeImage() before using this method.") 581 if not os.path.exists(path): 582 raise ValueError("Path [%s] does not exist." % path) 583 self._image.entries[path] = graftPoint
584
585 - def setImageNewDisc(self, newDisc):
586 """ 587 Resets (overrides) the newDisc flag on the internal image. 588 @param newDisc: New disc flag to set 589 @raise ValueError: If initializeImage() was not previously called 590 """ 591 if self._image is None: 592 raise ValueError("Must call initializeImage() before using this method.") 593 self._image.newDisc = newDisc
594
595 - def getEstimatedImageSize(self):
596 """ 597 Gets the estimated size of the image associated with the writer. 598 599 This is an estimate and is conservative. The actual image could be as 600 much as 450 blocks (sectors) smaller under some circmstances. 601 602 @return: Estimated size of the image, in bytes. 603 604 @raise IOError: If there is a problem calling C{mkisofs}. 605 @raise ValueError: If initializeImage() was not previously called 606 """ 607 if self._image is None: 608 raise ValueError("Must call initializeImage() before using this method.") 609 return DvdWriter._getEstimatedImageSize(self._image.entries)
610 611 612 ###################################### 613 # Methods which expose device actions 614 ###################################### 615
616 - def openTray(self):
617 """ 618 Opens the device's tray and leaves it open. 619 620 This only works if the device has a tray and supports ejecting its media. 621 We have no way to know if the tray is currently open or closed, so we 622 just send the appropriate command and hope for the best. If the device 623 does not have a tray or does not support ejecting its media, then we do 624 nothing. 625 626 Starting with Debian wheezy on my backup hardware, I started seeing 627 consistent problems with the eject command. I couldn't tell whether 628 these problems were due to the device management system or to the new 629 kernel (3.2.0). Initially, I saw simple eject failures, possibly because 630 I was opening and closing the tray too quickly. I worked around that 631 behavior with the new ejectDelay flag. 632 633 Later, I sometimes ran into issues after writing an image to a disc: 634 eject would give errors like "unable to eject, last error: Inappropriate 635 ioctl for device". Various sources online (like Ubuntu bug #875543) 636 suggested that the drive was being locked somehow, and that the 637 workaround was to run 'eject -i off' to unlock it. Sure enough, that 638 fixed the problem for me, so now it's a normal error-handling strategy. 639 640 @raise IOError: If there is an error talking to the device. 641 """ 642 if self._deviceHasTray and self._deviceCanEject: 643 command = resolveCommand(EJECT_COMMAND) 644 args = [ self.device, ] 645 result = executeCommand(command, args)[0] 646 if result != 0: 647 logger.debug("Eject failed; attempting kludge of unlocking the tray before retrying.") 648 self.unlockTray() 649 result = executeCommand(command, args)[0] 650 if result != 0: 651 raise IOError("Error (%d) executing eject command to open tray (failed even after unlocking tray)." % result) 652 logger.debug("Kludge was apparently successful.") 653 if self.ejectDelay is not None: 654 logger.debug("Per configuration, sleeping %d seconds after opening tray." % self.ejectDelay) 655 time.sleep(self.ejectDelay)
656
657 - def unlockTray(self):
658 """ 659 Unlocks the device's tray via 'eject -i off'. 660 @raise IOError: If there is an error talking to the device. 661 """ 662 command = resolveCommand(EJECT_COMMAND) 663 args = [ "-i", "off", self.device, ] 664 result = executeCommand(command, args)[0] 665 if result != 0: 666 raise IOError("Error (%d) executing eject command to unlock tray." % result)
667
668 - def closeTray(self):
669 """ 670 Closes the device's tray. 671 672 This only works if the device has a tray and supports ejecting its media. 673 We have no way to know if the tray is currently open or closed, so we 674 just send the appropriate command and hope for the best. If the device 675 does not have a tray or does not support ejecting its media, then we do 676 nothing. 677 678 @raise IOError: If there is an error talking to the device. 679 """ 680 if self._deviceHasTray and self._deviceCanEject: 681 command = resolveCommand(EJECT_COMMAND) 682 args = [ "-t", self.device, ] 683 result = executeCommand(command, args)[0] 684 if result != 0: 685 raise IOError("Error (%d) executing eject command to close tray." % result)
686
687 - def refreshMedia(self):
688 """ 689 Opens and then immediately closes the device's tray, to refresh the 690 device's idea of the media. 691 692 Sometimes, a device gets confused about the state of its media. Often, 693 all it takes to solve the problem is to eject the media and then 694 immediately reload it. (There are also configurable eject and refresh 695 media delays which can be applied, for situations where this makes a 696 difference.) 697 698 This only works if the device has a tray and supports ejecting its media. 699 We have no way to know if the tray is currently open or closed, so we 700 just send the appropriate command and hope for the best. If the device 701 does not have a tray or does not support ejecting its media, then we do 702 nothing. The configured delays still apply, though. 703 704 @raise IOError: If there is an error talking to the device. 705 """ 706 self.openTray() 707 self.closeTray() 708 self.unlockTray() # on some systems, writing a disc leaves the tray locked, yikes! 709 if self.refreshMediaDelay is not None: 710 logger.debug("Per configuration, sleeping %d seconds to stabilize media state." % self.refreshMediaDelay) 711 time.sleep(self.refreshMediaDelay) 712 logger.debug("Media refresh complete; hopefully media state is stable now.")
713
714 - def writeImage(self, imagePath=None, newDisc=False, writeMulti=True):
715 """ 716 Writes an ISO image to the media in the device. 717 718 If C{newDisc} is passed in as C{True}, we assume that the entire disc 719 will be re-created from scratch. Note that unlike C{CdWriter}, 720 C{DvdWriter} does not blank rewritable media before reusing it; however, 721 C{growisofs} is called such that the media will be re-initialized as 722 needed. 723 724 If C{imagePath} is passed in as C{None}, then the existing image 725 configured with C{initializeImage()} will be used. Under these 726 circumstances, the passed-in C{newDisc} flag will be ignored and the 727 value passed in to C{initializeImage()} will apply instead. 728 729 The C{writeMulti} argument is ignored. It exists for compatibility with 730 the Cedar Backup image writer interface. 731 732 @note: The image size indicated in the log ("Image size will be...") is 733 an estimate. The estimate is conservative and is probably larger than 734 the actual space that C{dvdwriter} will use. 735 736 @param imagePath: Path to an ISO image on disk, or C{None} to use writer's image 737 @type imagePath: String representing a path on disk 738 739 @param newDisc: Indicates whether the disc should be re-initialized 740 @type newDisc: Boolean true/false. 741 742 @param writeMulti: Unused 743 @type writeMulti: Boolean true/false 744 745 @raise ValueError: If the image path is not absolute. 746 @raise ValueError: If some path cannot be encoded properly. 747 @raise IOError: If the media could not be written to for some reason. 748 @raise ValueError: If no image is passed in and initializeImage() was not previously called 749 """ 750 if not writeMulti: 751 logger.warn("writeMulti value of [%s] ignored." % writeMulti) 752 if imagePath is None: 753 if self._image is None: 754 raise ValueError("Must call initializeImage() before using this method with no image path.") 755 size = self.getEstimatedImageSize() 756 logger.info("Image size will be %s (estimated)." % displayBytes(size)) 757 available = self.retrieveCapacity(entireDisc=self._image.newDisc).bytesAvailable 758 if size > available: 759 logger.error("Image [%s] does not fit in available capacity [%s]." % (displayBytes(size), displayBytes(available))) 760 raise IOError("Media does not contain enough capacity to store image.") 761 self._writeImage(self._image.newDisc, None, self._image.entries, self._image.mediaLabel) 762 else: 763 if not os.path.isabs(imagePath): 764 raise ValueError("Image path must be absolute.") 765 imagePath = encodePath(imagePath) 766 self._writeImage(newDisc, imagePath, None)
767 768 769 ################################################################## 770 # Utility methods for dealing with growisofs and dvd+rw-mediainfo 771 ################################################################## 772
773 - def _writeImage(self, newDisc, imagePath, entries, mediaLabel=None):
774 """ 775 Writes an image to disc using either an entries list or an ISO image on 776 disk. 777 778 Callers are assumed to have done validation on paths, etc. before calling 779 this method. 780 781 @param newDisc: Indicates whether the disc should be re-initialized 782 @param imagePath: Path to an ISO image on disk, or c{None} to use C{entries} 783 @param entries: Mapping from path to graft point, or C{None} to use C{imagePath} 784 785 @raise IOError: If the media could not be written to for some reason. 786 """ 787 command = resolveCommand(GROWISOFS_COMMAND) 788 args = DvdWriter._buildWriteArgs(newDisc, self.hardwareId, self._driveSpeed, imagePath, entries, mediaLabel, dryRun=False) 789 (result, output) = executeCommand(command, args, returnOutput=True) 790 if result != 0: 791 DvdWriter._searchForOverburn(output) # throws own exception if overburn condition is found 792 raise IOError("Error (%d) executing command to write disc." % result) 793 self.refreshMedia()
794 795 @staticmethod
796 - def _getEstimatedImageSize(entries):
797 """ 798 Gets the estimated size of a set of image entries. 799 800 This is implemented in terms of the C{IsoImage} class. The returned 801 value is calculated by adding a "fudge factor" to the value from 802 C{IsoImage}. This fudge factor was determined by experimentation and is 803 conservative -- the actual image could be as much as 450 blocks smaller 804 under some circumstances. 805 806 @param entries: Dictionary mapping path to graft point. 807 808 @return: Total estimated size of image, in bytes. 809 810 @raise ValueError: If there are no entries in the dictionary 811 @raise ValueError: If any path in the dictionary does not exist 812 @raise IOError: If there is a problem calling C{mkisofs}. 813 """ 814 fudgeFactor = convertSize(2500.0, UNIT_SECTORS, UNIT_BYTES) # determined through experimentation 815 if len(entries.keys()) == 0: 816 raise ValueError("Must add at least one entry with addImageEntry().") 817 image = IsoImage() 818 for path in entries.keys(): 819 image.addEntry(path, entries[path], override=False, contentsOnly=True) 820 estimatedSize = image.getEstimatedSize() + fudgeFactor 821 return estimatedSize
822
823 - def _retrieveSectorsUsed(self):
824 """ 825 Retrieves the number of sectors used on the current media. 826 827 This is a little ugly. We need to call growisofs in "dry-run" mode and 828 parse some information from its output. However, to do that, we need to 829 create a dummy file that we can pass to the command -- and we have to 830 make sure to remove it later. 831 832 Once growisofs has been run, then we call C{_parseSectorsUsed} to parse 833 the output and calculate the number of sectors used on the media. 834 835 @return: Number of sectors used on the media 836 """ 837 tempdir = tempfile.mkdtemp() 838 try: 839 entries = { tempdir: None } 840 args = DvdWriter._buildWriteArgs(False, self.hardwareId, self.driveSpeed, None, entries, None, dryRun=True) 841 command = resolveCommand(GROWISOFS_COMMAND) 842 (result, output) = executeCommand(command, args, returnOutput=True) 843 if result != 0: 844 logger.debug("Error (%d) calling growisofs to read sectors used." % result) 845 logger.warn("Unable to read disc (might not be initialized); returning zero sectors used.") 846 return 0.0 847 sectorsUsed = DvdWriter._parseSectorsUsed(output) 848 logger.debug("Determined sectors used as %s" % sectorsUsed) 849 return sectorsUsed 850 finally: 851 if os.path.exists(tempdir): 852 try: 853 os.rmdir(tempdir) 854 except: pass
855 856 @staticmethod
857 - def _parseSectorsUsed(output):
858 """ 859 Parse sectors used information out of C{growisofs} output. 860 861 The first line of a growisofs run looks something like this:: 862 863 Executing 'mkisofs -C 973744,1401056 -M /dev/fd/3 -r -graft-points music4/=music | builtin_dd of=/dev/cdrom obs=32k seek=87566' 864 865 Dmitry has determined that the seek value in this line gives us 866 information about how much data has previously been written to the media. 867 That value multiplied by 16 yields the number of sectors used. 868 869 If the seek line cannot be found in the output, then sectors used of zero 870 is assumed. 871 872 @return: Sectors used on the media, as a floating point number. 873 874 @raise ValueError: If the output cannot be parsed properly. 875 """ 876 if output is not None: 877 pattern = re.compile(r"(^)(.*)(seek=)(.*)('$)") 878 for line in output: 879 match = pattern.search(line) 880 if match is not None: 881 try: 882 return float(match.group(4).strip()) * 16.0 883 except ValueError: 884 raise ValueError("Unable to parse sectors used out of growisofs output.") 885 logger.warn("Unable to read disc (might not be initialized); returning zero sectors used.") 886 return 0.0
887 888 @staticmethod
889 - def _searchForOverburn(output):
890 """ 891 Search for an "overburn" error message in C{growisofs} output. 892 893 The C{growisofs} command returns a non-zero exit code and puts a message 894 into the output -- even on a dry run -- if there is not enough space on 895 the media. This is called an "overburn" condition. 896 897 The error message looks like this:: 898 899 :-( /dev/cdrom: 894048 blocks are free, 2033746 to be written! 900 901 This method looks for the overburn error message anywhere in the output. 902 If a matching error message is found, an C{IOError} exception is raised 903 containing relevant information about the problem. Otherwise, the method 904 call returns normally. 905 906 @param output: List of output lines to search, as from C{executeCommand} 907 908 @raise IOError: If an overburn condition is found. 909 """ 910 if output is None: 911 return 912 pattern = re.compile(r"(^)(:-[(])(\s*.*:\s*)(.* )(blocks are free, )(.* )(to be written!)") 913 for line in output: 914 match = pattern.search(line) 915 if match is not None: 916 try: 917 available = convertSize(float(match.group(4).strip()), UNIT_SECTORS, UNIT_BYTES) 918 size = convertSize(float(match.group(6).strip()), UNIT_SECTORS, UNIT_BYTES) 919 logger.error("Image [%s] does not fit in available capacity [%s]." % (displayBytes(size), displayBytes(available))) 920 except ValueError: 921 logger.error("Image does not fit in available capacity (no useful capacity info available).") 922 raise IOError("Media does not contain enough capacity to store image.")
923 924 @staticmethod
925 - def _buildWriteArgs(newDisc, hardwareId, driveSpeed, imagePath, entries, mediaLabel=None, dryRun=False):
926 """ 927 Builds a list of arguments to be passed to a C{growisofs} command. 928 929 The arguments will either cause C{growisofs} to write the indicated image 930 file to disc, or will pass C{growisofs} a list of directories or files 931 that should be written to disc. 932 933 If a new image is created, it will always be created with Rock Ridge 934 extensions (-r). A volume name will be applied (-V) if C{mediaLabel} is 935 not C{None}. 936 937 @param newDisc: Indicates whether the disc should be re-initialized 938 @param hardwareId: Hardware id for the device 939 @param driveSpeed: Speed at which the drive writes. 940 @param imagePath: Path to an ISO image on disk, or c{None} to use C{entries} 941 @param entries: Mapping from path to graft point, or C{None} to use C{imagePath} 942 @param mediaLabel: Media label to set on the image, if any 943 @param dryRun: Says whether to make this a dry run (for checking capacity) 944 945 @note: If we write an existing image to disc, then the mediaLabel is 946 ignored. The media label is an attribute of the image, and should be set 947 on the image when it is created. 948 949 @note: We always pass the undocumented option C{-use-the-force-like=tty} 950 to growisofs. Without this option, growisofs will refuse to execute 951 certain actions when running from cron. A good example is -Z, which 952 happily overwrites an existing DVD from the command-line, but fails when 953 run from cron. It took a while to figure that out, since it worked every 954 time I tested it by hand. :( 955 956 @return: List suitable for passing to L{util.executeCommand} as C{args}. 957 958 @raise ValueError: If caller does not pass one or the other of imagePath or entries. 959 """ 960 args = [] 961 if (imagePath is None and entries is None) or (imagePath is not None and entries is not None): 962 raise ValueError("Must use either imagePath or entries.") 963 args.append("-use-the-force-luke=tty") # tell growisofs to let us run from cron 964 if dryRun: 965 args.append("-dry-run") 966 if driveSpeed is not None: 967 args.append("-speed=%d" % driveSpeed) 968 if newDisc: 969 args.append("-Z") 970 else: 971 args.append("-M") 972 if imagePath is not None: 973 args.append("%s=%s" % (hardwareId, imagePath)) 974 else: 975 args.append(hardwareId) 976 if mediaLabel is not None: 977 args.append("-V") 978 args.append(mediaLabel) 979 args.append("-r") # Rock Ridge extensions with sane ownership and permissions 980 args.append("-graft-points") 981 keys = entries.keys() 982 keys.sort() # just so we get consistent results 983 for key in keys: 984 # Same syntax as when calling mkisofs in IsoImage 985 if entries[key] is None: 986 args.append(key) 987 else: 988 args.append("%s/=%s" % (entries[key].strip("/"), key)) 989 return args
990