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." 
  7  #           S O F T W A R E 
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 10  # 
 11  # Copyright (c) 2007-2008 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. 
 17  # 
 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 
 23  # the Free Software Foundation website, http://www.gnu.org/. 
 24  # 
 25  # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
 26  # 
 27  # Author   : Kenneth J. Pronovici <pronovic@ieee.org> 
 28  # Language : Python (>= 2.3) 
 29  # Project  : Cedar Backup, release 2 
 30  # Revision : $Id: dvdwriter.py 871 2008-03-19 01:27:24Z 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   
 61  # Cedar Backup modules 
 62  from CedarBackup2.filesystem import BackupFileList 
 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, unittest=False):
365 """ 366 Initializes a DVD writer object. 367 368 Since C{growisofs} can only address devices using the device path (i.e. 369 C{/dev/dvd}), the hardware id will always be set based on the device. If 370 passed in, it will be saved for reference purposes only. 371 372 We have no way to query the device to ask whether it has a tray or can be 373 safely opened and closed. So, the C{noEject} flag is used to set these 374 values. If C{noEject=False}, then we assume a tray exists and open/close 375 is safe. If C{noEject=True}, then we assume that there is no tray and 376 open/close is not safe. 377 378 @note: The C{unittest} parameter should never be set to C{True} 379 outside of Cedar Backup code. It is intended for use in unit testing 380 Cedar Backup internals and has no other sensible purpose. 381 382 @param device: Filesystem device associated with this writer. 383 @type device: Absolute path to a filesystem device, i.e. C{/dev/dvd} 384 385 @param scsiId: SCSI id for the device (optional, for reference only). 386 @type scsiId: If provided, SCSI id in the form C{[<method>:]scsibus,target,lun} 387 388 @param driveSpeed: Speed at which the drive writes. 389 @type driveSpeed: Use C{2} for 2x device, etc. or C{None} to use device default. 390 391 @param mediaType: Type of the media that is assumed to be in the drive. 392 @type mediaType: One of the valid media type as discussed above. 393 394 @param noEject: Tells Cedar Backup that the device cannot safely be ejected 395 @type noEject: Boolean true/false 396 397 @param unittest: Turns off certain validations, for use in unit testing. 398 @type unittest: Boolean true/false 399 400 @raise ValueError: If the device is not valid for some reason. 401 @raise ValueError: If the SCSI id is not in a valid form. 402 @raise ValueError: If the drive speed is not an integer >= 1. 403 """ 404 if scsiId is not None: 405 logger.warn("SCSI id [%s] will be ignored by DvdWriter." % scsiId) 406 self._image = None # optionally filled in by initializeImage() 407 self._device = validateDevice(device, unittest) 408 self._scsiId = scsiId # not validated, because it's just for reference 409 self._driveSpeed = validateDriveSpeed(driveSpeed) 410 self._media = MediaDefinition(mediaType) 411 if noEject: 412 self._deviceHasTray = False 413 self._deviceCanEject = False 414 else: 415 self._deviceHasTray = True # just assume 416 self._deviceCanEject = True # just assume
417 418 419 ############# 420 # Properties 421 ############# 422
423 - def _getDevice(self):
424 """ 425 Property target used to get the device value. 426 """ 427 return self._device
428
429 - def _getScsiId(self):
430 """ 431 Property target used to get the SCSI id value. 432 """ 433 return self._scsiId
434
435 - def _getHardwareId(self):
436 """ 437 Property target used to get the hardware id value. 438 """ 439 return self._device
440
441 - def _getDriveSpeed(self):
442 """ 443 Property target used to get the drive speed. 444 """ 445 return self._driveSpeed
446
447 - def _getMedia(self):
448 """ 449 Property target used to get the media description. 450 """ 451 return self._media
452
453 - def _getDeviceHasTray(self):
454 """ 455 Property target used to get the device-has-tray flag. 456 """ 457 return self._deviceHasTray
458
459 - def _getDeviceCanEject(self):
460 """ 461 Property target used to get the device-can-eject flag. 462 """ 463 return self._deviceCanEject
464 465 device = property(_getDevice, None, None, doc="Filesystem device name for this writer.") 466 scsiId = property(_getScsiId, None, None, doc="SCSI id for the device (saved for reference only).") 467 hardwareId = property(_getHardwareId, None, None, doc="Hardware id for this writer (always the device path)."); 468 driveSpeed = property(_getDriveSpeed, None, None, doc="Speed at which the drive writes.") 469 media = property(_getMedia, None, None, doc="Definition of media that is expected to be in the device.") 470 deviceHasTray = property(_getDeviceHasTray, None, None, doc="Indicates whether the device has a media tray.") 471 deviceCanEject = property(_getDeviceCanEject, None, None, doc="Indicates whether the device supports ejecting its media.") 472 473 474 ################################################# 475 # Methods related to device and media attributes 476 ################################################# 477
478 - def isRewritable(self):
479 """Indicates whether the media is rewritable per configuration.""" 480 return self._media.rewritable
481
482 - def retrieveCapacity(self, entireDisc=False):
483 """ 484 Retrieves capacity for the current media in terms of a C{MediaCapacity} 485 object. 486 487 If C{entireDisc} is passed in as C{True}, the capacity will be for the 488 entire disc, as if it were to be rewritten from scratch. The same will 489 happen if the disc can't be read for some reason. Otherwise, the capacity 490 will be calculated by subtracting the sectors currently used on the disc, 491 as reported by C{growisofs} itself. 492 493 @param entireDisc: Indicates whether to return capacity for entire disc. 494 @type entireDisc: Boolean true/false 495 496 @return: C{MediaCapacity} object describing the capacity of the media. 497 498 @raise ValueError: If there is a problem parsing the C{growisofs} output 499 @raise IOError: If the media could not be read for some reason. 500 """ 501 sectorsUsed = 0 502 if not entireDisc: 503 sectorsUsed = self._retrieveSectorsUsed() 504 sectorsAvailable = self._media.capacity - sectorsUsed # both are in sectors 505 bytesUsed = convertSize(sectorsUsed, UNIT_SECTORS, UNIT_BYTES) 506 bytesAvailable = convertSize(sectorsAvailable, UNIT_SECTORS, UNIT_BYTES) 507 return MediaCapacity(bytesUsed, bytesAvailable)
508 509 510 ####################################################### 511 # Methods used for working with the internal ISO image 512 ####################################################### 513
514 - def initializeImage(self, newDisc, tmpdir, mediaLabel=None):
515 """ 516 Initializes the writer's associated ISO image. 517 518 This method initializes the C{image} instance variable so that the caller 519 can use the C{addImageEntry} method. Once entries have been added, the 520 C{writeImage} method can be called with no arguments. 521 522 @param newDisc: Indicates whether the disc should be re-initialized 523 @type newDisc: Boolean true/false 524 525 @param tmpdir: Temporary directory to use if needed 526 @type tmpdir: String representing a directory path on disk 527 528 @param mediaLabel: Media label to be applied to the image, if any 529 @type mediaLabel: String, no more than 25 characters long 530 """ 531 self._image = _ImageProperties() 532 self._image.newDisc = newDisc 533 self._image.tmpdir = encodePath(tmpdir) 534 self._image.mediaLabel = mediaLabel 535 self._image.entries = {} # mapping from path to graft point (if any)
536
537 - def addImageEntry(self, path, graftPoint):
538 """ 539 Adds a filepath entry to the writer's associated ISO image. 540 541 The contents of the filepath -- but not the path itself -- will be added 542 to the image at the indicated graft point. If you don't want to use a 543 graft point, just pass C{None}. 544 545 @note: Before calling this method, you must call L{initializeImage}. 546 547 @param path: File or directory to be added to the image 548 @type path: String representing a path on disk 549 550 @param graftPoint: Graft point to be used when adding this entry 551 @type graftPoint: String representing a graft point path, as described above 552 553 @raise ValueError: If initializeImage() was not previously called 554 @raise ValueError: If the path is not a valid file or directory 555 """ 556 if self._image is None: 557 raise ValueError("Must call initializeImage() before using this method.") 558 if not os.path.exists(path): 559 raise ValueError("Path [%s] does not exist." % path) 560 self._image.entries[path] = graftPoint
561
562 - def setImageNewDisc(self, newDisc):
563 """ 564 Resets (overrides) the newDisc flag on the internal image. 565 @param newDisc: New disc flag to set 566 @raise ValueError: If initializeImage() was not previously called 567 """ 568 if self._image is None: 569 raise ValueError("Must call initializeImage() before using this method.") 570 self._image.newDisc = newDisc
571
572 - def getEstimatedImageSize(self):
573 """ 574 Gets the estimated size of the image associated with the writer. 575 576 This is an estimate and is conservative. The actual image could be as 577 much as 450 blocks (sectors) smaller under some circmstances. 578 579 @return: Estimated size of the image, in bytes. 580 581 @raise IOError: If there is a problem calling C{mkisofs}. 582 @raise ValueError: If initializeImage() was not previously called 583 """ 584 if self._image is None: 585 raise ValueError("Must call initializeImage() before using this method.") 586 return DvdWriter._getEstimatedImageSize(self._image.entries)
587 588 589 ###################################### 590 # Methods which expose device actions 591 ###################################### 592
593 - def openTray(self):
594 """ 595 Opens the device's tray and leaves it open. 596 597 This only works if the device has a tray and supports ejecting its media. 598 We have no way to know if the tray is currently open or closed, so we 599 just send the appropriate command and hope for the best. If the device 600 does not have a tray or does not support ejecting its media, then we do 601 nothing. 602 603 @raise IOError: If there is an error talking to the device. 604 """ 605 if self._deviceHasTray and self._deviceCanEject: 606 command = resolveCommand(EJECT_COMMAND) 607 args = [ self.device, ] 608 result = executeCommand(command, args)[0] 609 if result != 0: 610 raise IOError("Error (%d) executing eject command to open tray." % result)
611
612 - def closeTray(self):
613 """ 614 Closes the device's tray. 615 616 This only works if the device has a tray and supports ejecting its media. 617 We have no way to know if the tray is currently open or closed, so we 618 just send the appropriate command and hope for the best. If the device 619 does not have a tray or does not support ejecting its media, then we do 620 nothing. 621 622 @raise IOError: If there is an error talking to the device. 623 """ 624 if self._deviceHasTray and self._deviceCanEject: 625 command = resolveCommand(EJECT_COMMAND) 626 args = [ "-t", self.device, ] 627 result = executeCommand(command, args)[0] 628 if result != 0: 629 raise IOError("Error (%d) executing eject command to close tray." % result)
630
631 - def refreshMedia(self):
632 """ 633 Opens and then immediately closes the device's tray, to refresh the 634 device's idea of the media. 635 636 Sometimes, a device gets confused about the state of its media. Often, 637 all it takes to solve the problem is to eject the media and then 638 immediately reload it. 639 640 This only works if the device has a tray and supports ejecting its media. 641 We have no way to know if the tray is currently open or closed, so we 642 just send the appropriate command and hope for the best. If the device 643 does not have a tray or does not support ejecting its media, then we do 644 nothing. 645 646 @raise IOError: If there is an error talking to the device. 647 """ 648 self.openTray() 649 self.closeTray()
650
651 - def writeImage(self, imagePath=None, newDisc=False, writeMulti=True):
652 """ 653 Writes an ISO image to the media in the device. 654 655 If C{newDisc} is passed in as C{True}, we assume that the entire disc 656 will be re-created from scratch. Note that unlike C{CdWriter}, 657 C{DvdWriter} does not blank rewritable media before reusing it; however, 658 C{growisofs} is called such that the media will be re-initialized as 659 needed. 660 661 If C{imagePath} is passed in as C{None}, then the existing image 662 configured with C{initializeImage()} will be used. Under these 663 circumstances, the passed-in C{newDisc} flag will be ignored and the 664 value passed in to C{initializeImage()} will apply instead. 665 666 The C{writeMulti} argument is ignored. It exists for compatibility with 667 the Cedar Backup image writer interface. 668 669 @note: The image size indicated in the log ("Image size will be...") is 670 an estimate. The estimate is conservative and is probably larger than 671 the actual space that C{dvdwriter} will use. 672 673 @param imagePath: Path to an ISO image on disk, or C{None} to use writer's image 674 @type imagePath: String representing a path on disk 675 676 @param newDisc: Indicates whether the disc should be re-initialized 677 @type newDisc: Boolean true/false. 678 679 @param writeMulti: Unused 680 @type writeMulti: Boolean true/false 681 682 @raise ValueError: If the image path is not absolute. 683 @raise ValueError: If some path cannot be encoded properly. 684 @raise IOError: If the media could not be written to for some reason. 685 @raise ValueError: If no image is passed in and initializeImage() was not previously called 686 """ 687 if not writeMulti: 688 logger.warn("writeMulti value of [%s] ignored." % writeMulti) 689 if imagePath is None: 690 if self._image is None: 691 raise ValueError("Must call initializeImage() before using this method with no image path.") 692 size = self.getEstimatedImageSize() 693 logger.info("Image size will be %s (estimated)." % displayBytes(size)) 694 available = self.retrieveCapacity(entireDisc=self._image.newDisc).bytesAvailable 695 if size > available: 696 logger.error("Image [%s] does not fit in available capacity [%s]." % (displayBytes(size), displayBytes(available))) 697 raise IOError("Media does not contain enough capacity to store image.") 698 self._writeImage(self._image.newDisc, None, self._image.entries, self._image.mediaLabel) 699 else: 700 if not os.path.isabs(imagePath): 701 raise ValueError("Image path must be absolute.") 702 imagePath = encodePath(imagePath) 703 self._writeImage(newDisc, imagePath, None)
704 705 706 ################################################################## 707 # Utility methods for dealing with growisofs and dvd+rw-mediainfo 708 ################################################################## 709
710 - def _writeImage(self, newDisc, imagePath, entries, mediaLabel=None):
711 """ 712 Writes an image to disc using either an entries list or an ISO image on 713 disk. 714 715 Callers are assumed to have done validation on paths, etc. before calling 716 this method. 717 718 @param newDisc: Indicates whether the disc should be re-initialized 719 @param imagePath: Path to an ISO image on disk, or c{None} to use C{entries} 720 @param entries: Mapping from path to graft point, or C{None} to use C{imagePath} 721 722 @raise IOError: If the media could not be written to for some reason. 723 """ 724 command = resolveCommand(GROWISOFS_COMMAND) 725 args = DvdWriter._buildWriteArgs(newDisc, self.hardwareId, self._driveSpeed, imagePath, entries, mediaLabel, dryRun=False) 726 (result, output) = executeCommand(command, args, returnOutput=True) 727 if result != 0: 728 DvdWriter._searchForOverburn(output) # throws own exception if overburn condition is found 729 raise IOError("Error (%d) executing command to write disc." % result) 730 self.refreshMedia()
731
732 - def _getEstimatedImageSize(entries):
733 """ 734 Gets the estimated size of a set of image entries. 735 736 This is implemented in terms of the C{IsoImage} class. The returned 737 value is calculated by adding a "fudge factor" to the value from 738 C{IsoImage}. This fudge factor was determined by experimentation and is 739 conservative -- the actual image could be as much as 450 blocks smaller 740 under some circumstances. 741 742 @param entries: Dictionary mapping path to graft point. 743 744 @return: Total estimated size of image, in bytes. 745 746 @raise ValueError: If there are no entries in the dictionary 747 @raise ValueError: If any path in the dictionary does not exist 748 @raise IOError: If there is a problem calling C{mkisofs}. 749 """ 750 fudgeFactor = convertSize(2500.0, UNIT_SECTORS, UNIT_BYTES) # determined through experimentation 751 if len(entries.keys()) == 0: 752 raise ValueError("Must add at least one entry with addImageEntry().") 753 image = IsoImage() 754 for path in entries.keys(): 755 image.addEntry(path, entries[path], override=False, contentsOnly=True) 756 estimatedSize = image.getEstimatedSize() + fudgeFactor 757 return estimatedSize
758 _getEstimatedImageSize = staticmethod(_getEstimatedImageSize) 759
760 - def _retrieveSectorsUsed(self):
761 """ 762 Retrieves the number of sectors used on the current media. 763 764 This is a little ugly. We need to call growisofs in "dry-run" mode and 765 parse some information from its output. However, to do that, we need to 766 create a dummy file that we can pass to the command -- and we have to 767 make sure to remove it later. 768 769 Once growisofs has been run, then we call C{_parseSectorsUsed} to parse 770 the output and calculate the number of sectors used on the media. 771 772 @return: Number of sectors used on the media 773 """ 774 tempdir = tempfile.mkdtemp() 775 try: 776 entries = { tempdir: None } 777 args = DvdWriter._buildWriteArgs(False, self.hardwareId, self.driveSpeed, None, entries, None, dryRun=True) 778 command = resolveCommand(GROWISOFS_COMMAND) 779 (result, output) = executeCommand(command, args, returnOutput=True) 780 if result != 0: 781 logger.debug("Error (%d) calling growisofs to read sectors used." % result) 782 logger.warn("Unable to read disc (might not be initialized); returning zero sectors used.") 783 return 0.0 784 sectorsUsed = DvdWriter._parseSectorsUsed(output) 785 logger.debug("Determined sectors used as %s" % sectorsUsed) 786 return sectorsUsed 787 finally: 788 if os.path.exists(tempdir): 789 try: 790 os.rmdir(tempdir) 791 except: pass
792
793 - def _parseSectorsUsed(output):
794 """ 795 Parse sectors used information out of C{growisofs} output. 796 797 The first line of a growisofs run looks something like this:: 798 799 Executing 'mkisofs -C 973744,1401056 -M /dev/fd/3 -r -graft-points music4/=music | builtin_dd of=/dev/cdrom obs=32k seek=87566' 800 801 Dmitry has determined that the seek value in this line gives us 802 information about how much data has previously been written to the media. 803 That value multiplied by 16 yields the number of sectors used. 804 805 If the seek line cannot be found in the output, then sectors used of zero 806 is assumed. 807 808 @return: Sectors used on the media, as a floating point number. 809 810 @raise ValueError: If the output cannot be parsed properly. 811 """ 812 if output is not None: 813 pattern = re.compile(r"(^)(.*)(seek=)(.*)('$)") 814 for line in output: 815 match = pattern.search(line) 816 if match is not None: 817 try: 818 return float(match.group(4).strip()) * 16.0 819 except ValueError: 820 raise ValueError("Unable to parse sectors used out of growisofs output.") 821 logger.warn("Unable to read disc (might not be initialized); returning zero sectors used.") 822 return 0.0
823 _parseSectorsUsed = staticmethod(_parseSectorsUsed) 824
825 - def _searchForOverburn(output):
826 """ 827 Search for an "overburn" error message in C{growisofs} output. 828 829 The C{growisofs} command returns a non-zero exit code and puts a message 830 into the output -- even on a dry run -- if there is not enough space on 831 the media. This is called an "overburn" condition. 832 833 The error message looks like this:: 834 835 :-( /dev/cdrom: 894048 blocks are free, 2033746 to be written! 836 837 This method looks for the overburn error message anywhere in the output. 838 If a matching error message is found, an C{IOError} exception is raised 839 containing relevant information about the problem. Otherwise, the method 840 call returns normally. 841 842 @param output: List of output lines to search, as from C{executeCommand} 843 844 @raise IOError: If an overburn condition is found. 845 """ 846 if output is None: 847 return 848 pattern = re.compile(r"(^)(:-[(])(\s*.*:\s*)(.* )(blocks are free, )(.* )(to be written!)") 849 for line in output: 850 match = pattern.search(line) 851 if match is not None: 852 try: 853 available = convertSize(float(match.group(4).strip()), UNIT_SECTORS, UNIT_BYTES) 854 size = convertSize(float(match.group(6).strip()), UNIT_SECTORS, UNIT_BYTES) 855 logger.error("Image [%s] does not fit in available capacity [%s]." % (displayBytes(size), displayBytes(available))) 856 except ValueError: 857 logger.error("Image does not fit in available capacity (no useful capacity info available).") 858 raise IOError("Media does not contain enough capacity to store image.")
859 _searchForOverburn = staticmethod(_searchForOverburn) 860
861 - def _buildWriteArgs(newDisc, hardwareId, driveSpeed, imagePath, entries, mediaLabel=None, dryRun=False):
862 """ 863 Builds a list of arguments to be passed to a C{growisofs} command. 864 865 The arguments will either cause C{growisofs} to write the indicated image 866 file to disc, or will pass C{growisofs} a list of directories or files 867 that should be written to disc. 868 869 If a new image is created, it will always be created with Rock Ridge 870 extensions (-r). A volume name will be applied (-V) if C{mediaLabel} is 871 not C{None}. 872 873 @param newDisc: Indicates whether the disc should be re-initialized 874 @param hardwareId: Hardware id for the device 875 @param driveSpeed: Speed at which the drive writes. 876 @param imagePath: Path to an ISO image on disk, or c{None} to use C{entries} 877 @param entries: Mapping from path to graft point, or C{None} to use C{imagePath} 878 @param mediaLabel: Media label to set on the image, if any 879 @param dryRun: Says whether to make this a dry run (for checking capacity) 880 881 @note: If we write an existing image to disc, then the mediaLabel is 882 ignored. The media label is an attribute of the image, and should be set 883 on the image when it is created. 884 885 @note: We always pass the undocumented option C{-use-the-force-like=tty} 886 to growisofs. Without this option, growisofs will refuse to execute 887 certain actions when running from cron. A good example is -Z, which 888 happily overwrites an existing DVD from the command-line, but fails when 889 run from cron. It took a while to figure that out, since it worked every 890 time I tested it by hand. :( 891 892 @return: List suitable for passing to L{util.executeCommand} as C{args}. 893 894 @raise ValueError: If caller does not pass one or the other of imagePath or entries. 895 """ 896 args = [] 897 if (imagePath is None and entries is None) or (imagePath is not None and entries is not None): 898 raise ValueError("Must use either imagePath or entries.") 899 args.append("-use-the-force-luke=tty") # tell growisofs to let us run from cron 900 if dryRun: 901 args.append("-dry-run") 902 if driveSpeed is not None: 903 args.append("-speed=%d" % driveSpeed) 904 if newDisc: 905 args.append("-Z") 906 else: 907 args.append("-M") 908 if imagePath is not None: 909 args.append("%s=%s" % (hardwareId, imagePath)) 910 else: 911 args.append(hardwareId) 912 if mediaLabel is not None: 913 args.append("-V") 914 args.append(mediaLabel) 915 args.append("-r") # Rock Ridge extensions with sane ownership and permissions 916 args.append("-graft-points") 917 keys = entries.keys() 918 keys.sort() # just so we get consistent results 919 for key in keys: 920 # Same syntax as when calling mkisofs in IsoImage 921 if entries[key] is None: 922 args.append(key) 923 else: 924 args.append("%s/=%s" % (entries[key].strip("/"), key)) 925 return args
926 _buildWriteArgs = staticmethod(_buildWriteArgs)
927