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

   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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  11  # Copyright (c) 2004-2008,2010 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. 
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  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: cdwriter.py 1041 2013-05-10 02:05:13Z pronovic $ 
  31  # Purpose  : Provides functionality related to CD writer devices. 
  32  # 
  33  # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # 
  34   
  35  ######################################################################## 
  36  # Module documentation 
  37  ######################################################################## 
  38   
  39  """ 
  40  Provides functionality related to CD writer devices. 
  41   
  42  @sort: MediaDefinition, MediaCapacity, CdWriter, 
  43         MEDIA_CDRW_74, MEDIA_CDR_74, MEDIA_CDRW_80, MEDIA_CDR_80 
  44   
  45  @var MEDIA_CDRW_74: Constant representing 74-minute CD-RW media. 
  46  @var MEDIA_CDR_74: Constant representing 74-minute CD-R media. 
  47  @var MEDIA_CDRW_80: Constant representing 80-minute CD-RW media. 
  48  @var MEDIA_CDR_80: Constant representing 80-minute CD-R media. 
  49   
  50  @author: Kenneth J. Pronovici <pronovic@ieee.org> 
  51  """ 
  52   
  53  ######################################################################## 
  54  # Imported modules 
  55  ######################################################################## 
  56   
  57  # System modules 
  58  import os 
  59  import re 
  60  import logging 
  61  import tempfile 
  62  import time 
  63   
  64  # Cedar Backup modules 
  65  from CedarBackup2.util import resolveCommand, executeCommand 
  66  from CedarBackup2.util import convertSize, displayBytes, encodePath 
  67  from CedarBackup2.util import UNIT_SECTORS, UNIT_BYTES, UNIT_KBYTES, UNIT_MBYTES 
  68  from CedarBackup2.writers.util import validateDevice, validateScsiId, validateDriveSpeed 
  69  from CedarBackup2.writers.util import IsoImage 
  70   
  71   
  72  ######################################################################## 
  73  # Module-wide constants and variables 
  74  ######################################################################## 
  75   
  76  logger = logging.getLogger("CedarBackup2.log.writers.cdwriter") 
  77   
  78  MEDIA_CDRW_74  = 1 
  79  MEDIA_CDR_74   = 2 
  80  MEDIA_CDRW_80  = 3 
  81  MEDIA_CDR_80   = 4 
  82   
  83  CDRECORD_COMMAND = [ "cdrecord", ] 
  84  EJECT_COMMAND    = [ "eject", ] 
  85  MKISOFS_COMMAND  = [ "mkisofs", ] 
86 87 88 ######################################################################## 89 # MediaDefinition class definition 90 ######################################################################## 91 92 -class MediaDefinition(object):
93 94 """ 95 Class encapsulating information about CD media definitions. 96 97 The following media types are accepted: 98 99 - C{MEDIA_CDR_74}: 74-minute CD-R media (650 MB capacity) 100 - C{MEDIA_CDRW_74}: 74-minute CD-RW media (650 MB capacity) 101 - C{MEDIA_CDR_80}: 80-minute CD-R media (700 MB capacity) 102 - C{MEDIA_CDRW_80}: 80-minute CD-RW media (700 MB capacity) 103 104 Note that all of the capacities associated with a media definition are in 105 terms of ISO sectors (C{util.ISO_SECTOR_SIZE)}. 106 107 @sort: __init__, mediaType, rewritable, initialLeadIn, leadIn, capacity 108 """ 109
110 - def __init__(self, mediaType):
111 """ 112 Creates a media definition for the indicated media type. 113 @param mediaType: Type of the media, as discussed above. 114 @raise ValueError: If the media type is unknown or unsupported. 115 """ 116 self._mediaType = None 117 self._rewritable = False 118 self._initialLeadIn = 0. 119 self._leadIn = 0.0 120 self._capacity = 0.0 121 self._setValues(mediaType)
122
123 - def _setValues(self, mediaType):
124 """ 125 Sets values based on media type. 126 @param mediaType: Type of the media, as discussed above. 127 @raise ValueError: If the media type is unknown or unsupported. 128 """ 129 if mediaType not in [MEDIA_CDR_74, MEDIA_CDRW_74, MEDIA_CDR_80, MEDIA_CDRW_80]: 130 raise ValueError("Invalid media type %d." % mediaType) 131 self._mediaType = mediaType 132 self._initialLeadIn = 11400.0 # per cdrecord's documentation 133 self._leadIn = 6900.0 # per cdrecord's documentation 134 if self._mediaType == MEDIA_CDR_74: 135 self._rewritable = False 136 self._capacity = convertSize(650.0, UNIT_MBYTES, UNIT_SECTORS) 137 elif self._mediaType == MEDIA_CDRW_74: 138 self._rewritable = True 139 self._capacity = convertSize(650.0, UNIT_MBYTES, UNIT_SECTORS) 140 elif self._mediaType == MEDIA_CDR_80: 141 self._rewritable = False 142 self._capacity = convertSize(700.0, UNIT_MBYTES, UNIT_SECTORS) 143 elif self._mediaType == MEDIA_CDRW_80: 144 self._rewritable = True 145 self._capacity = convertSize(700.0, UNIT_MBYTES, UNIT_SECTORS)
146
147 - def _getMediaType(self):
148 """ 149 Property target used to get the media type value. 150 """ 151 return self._mediaType
152
153 - def _getRewritable(self):
154 """ 155 Property target used to get the rewritable flag value. 156 """ 157 return self._rewritable
158
159 - def _getInitialLeadIn(self):
160 """ 161 Property target used to get the initial lead-in value. 162 """ 163 return self._initialLeadIn
164
165 - def _getLeadIn(self):
166 """ 167 Property target used to get the lead-in value. 168 """ 169 return self._leadIn
170
171 - def _getCapacity(self):
172 """ 173 Property target used to get the capacity value. 174 """ 175 return self._capacity
176 177 mediaType = property(_getMediaType, None, None, doc="Configured media type.") 178 rewritable = property(_getRewritable, None, None, doc="Boolean indicating whether the media is rewritable.") 179 initialLeadIn = property(_getInitialLeadIn, None, None, doc="Initial lead-in required for first image written to media.") 180 leadIn = property(_getLeadIn, None, None, doc="Lead-in required on successive images written to media.") 181 capacity = property(_getCapacity, None, None, doc="Total capacity of the media before any required lead-in.")
182
183 184 ######################################################################## 185 # MediaCapacity class definition 186 ######################################################################## 187 188 -class MediaCapacity(object):
189 190 """ 191 Class encapsulating information about CD media capacity. 192 193 Space used includes the required media lead-in (unless the disk is unused). 194 Space available attempts to provide a picture of how many bytes are 195 available for data storage, including any required lead-in. 196 197 The boundaries value is either C{None} (if multisession discs are not 198 supported or if the disc has no boundaries) or in exactly the form provided 199 by C{cdrecord -msinfo}. It can be passed as-is to the C{IsoImage} class. 200 201 @sort: __init__, bytesUsed, bytesAvailable, boundaries, totalCapacity, utilized 202 """ 203
204 - def __init__(self, bytesUsed, bytesAvailable, boundaries):
205 """ 206 Initializes a capacity object. 207 @raise IndexError: If the boundaries tuple does not have enough elements. 208 @raise ValueError: If the boundaries values are not integers. 209 @raise ValueError: If the bytes used and available values are not floats. 210 """ 211 self._bytesUsed = float(bytesUsed) 212 self._bytesAvailable = float(bytesAvailable) 213 if boundaries is None: 214 self._boundaries = None 215 else: 216 self._boundaries = (int(boundaries[0]), int(boundaries[1]))
217
218 - def __str__(self):
219 """ 220 Informal string representation for class instance. 221 """ 222 return "utilized %s of %s (%.2f%%)" % (displayBytes(self.bytesUsed), displayBytes(self.totalCapacity), self.utilized)
223
224 - def _getBytesUsed(self):
225 """ 226 Property target to get the bytes-used value. 227 """ 228 return self._bytesUsed
229
230 - def _getBytesAvailable(self):
231 """ 232 Property target to get the bytes-available value. 233 """ 234 return self._bytesAvailable
235
236 - def _getBoundaries(self):
237 """ 238 Property target to get the boundaries tuple. 239 """ 240 return self._boundaries
241
242 - def _getTotalCapacity(self):
243 """ 244 Property target to get the total capacity (used + available). 245 """ 246 return self.bytesUsed + self.bytesAvailable
247
248 - def _getUtilized(self):
249 """ 250 Property target to get the percent of capacity which is utilized. 251 """ 252 if self.bytesAvailable <= 0.0: 253 return 100.0 254 elif self.bytesUsed <= 0.0: 255 return 0.0 256 return (self.bytesUsed / self.totalCapacity) * 100.0
257 258 bytesUsed = property(_getBytesUsed, None, None, doc="Space used on disc, in bytes.") 259 bytesAvailable = property(_getBytesAvailable, None, None, doc="Space available on disc, in bytes.") 260 boundaries = property(_getBoundaries, None, None, doc="Session disc boundaries, in terms of ISO sectors.") 261 totalCapacity = property(_getTotalCapacity, None, None, doc="Total capacity of the disc, in bytes.") 262 utilized = property(_getUtilized, None, None, "Percentage of the total capacity which is utilized.")
263
264 265 ######################################################################## 266 # _ImageProperties class definition 267 ######################################################################## 268 269 -class _ImageProperties(object):
270 """ 271 Simple value object to hold image properties for C{DvdWriter}. 272 """
273 - def __init__(self):
274 self.newDisc = False 275 self.tmpdir = None 276 self.mediaLabel = None 277 self.entries = None # dict mapping path to graft point
278
279 280 ######################################################################## 281 # CdWriter class definition 282 ######################################################################## 283 284 -class CdWriter(object):
285 286 ###################### 287 # Class documentation 288 ###################### 289 290 """ 291 Class representing a device that knows how to write CD media. 292 293 Summary 294 ======= 295 296 This is a class representing a device that knows how to write CD media. It 297 provides common operations for the device, such as ejecting the media, 298 writing an ISO image to the media, or checking for the current media 299 capacity. It also provides a place to store device attributes, such as 300 whether the device supports writing multisession discs, etc. 301 302 This class is implemented in terms of the C{eject} and C{cdrecord} 303 programs, both of which should be available on most UN*X platforms. 304 305 Image Writer Interface 306 ====================== 307 308 The following methods make up the "image writer" interface shared 309 with other kinds of writers (such as DVD writers):: 310 311 __init__ 312 initializeImage() 313 addImageEntry() 314 writeImage() 315 setImageNewDisc() 316 retrieveCapacity() 317 getEstimatedImageSize() 318 319 Only these methods will be used by other Cedar Backup functionality 320 that expects a compatible image writer. 321 322 The media attribute is also assumed to be available. 323 324 Media Types 325 =========== 326 327 This class knows how to write to two different kinds of media, represented 328 by the following constants: 329 330 - C{MEDIA_CDR_74}: 74-minute CD-R media (650 MB capacity) 331 - C{MEDIA_CDRW_74}: 74-minute CD-RW media (650 MB capacity) 332 - C{MEDIA_CDR_80}: 80-minute CD-R media (700 MB capacity) 333 - C{MEDIA_CDRW_80}: 80-minute CD-RW media (700 MB capacity) 334 335 Most hardware can read and write both 74-minute and 80-minute CD-R and 336 CD-RW media. Some older drives may only be able to write CD-R media. 337 The difference between the two is that CD-RW media can be rewritten 338 (erased), while CD-R media cannot be. 339 340 I do not support any other configurations for a couple of reasons. The 341 first is that I've never tested any other kind of media. The second is 342 that anything other than 74 or 80 minute is apparently non-standard. 343 344 Device Attributes vs. Media Attributes 345 ====================================== 346 347 A given writer instance has two different kinds of attributes associated 348 with it, which I call device attributes and media attributes. Device 349 attributes are things which can be determined without looking at the 350 media, such as whether the drive supports writing multisession disks or 351 has a tray. Media attributes are attributes which vary depending on the 352 state of the media, such as the remaining capacity on a disc. In 353 general, device attributes are available via instance variables and are 354 constant over the life of an object, while media attributes can be 355 retrieved through method calls. 356 357 Talking to Hardware 358 =================== 359 360 This class needs to talk to CD writer hardware in two different ways: 361 through cdrecord to actually write to the media, and through the 362 filesystem to do things like open and close the tray. 363 364 Historically, CdWriter has interacted with cdrecord using the scsiId 365 attribute, and with most other utilities using the device attribute. 366 This changed somewhat in Cedar Backup 2.9.0. 367 368 When Cedar Backup was first written, the only way to interact with 369 cdrecord was by using a SCSI device id. IDE devices were mapped to 370 pseudo-SCSI devices through the kernel. Later, extended SCSI "methods" 371 arrived, and it became common to see C{ATA:1,0,0} or C{ATAPI:0,0,0} as a 372 way to address IDE hardware. By late 2006, C{ATA} and C{ATAPI} had 373 apparently been deprecated in favor of just addressing the IDE device 374 directly by name, i.e. C{/dev/cdrw}. 375 376 Because of this latest development, it no longer makes sense to require a 377 CdWriter to be created with a SCSI id -- there might not be one. So, the 378 passed-in SCSI id is now optional. Also, there is now a hardwareId 379 attribute. This attribute is filled in with either the SCSI id (if 380 provided) or the device (otherwise). The hardware id is the value that 381 will be passed to cdrecord in the C{dev=} argument. 382 383 Testing 384 ======= 385 386 It's rather difficult to test this code in an automated fashion, even if 387 you have access to a physical CD writer drive. It's even more difficult 388 to test it if you are running on some build daemon (think of a Debian 389 autobuilder) which can't be expected to have any hardware or any media 390 that you could write to. 391 392 Because of this, much of the implementation below is in terms of static 393 methods that are supposed to take defined actions based on their 394 arguments. Public methods are then implemented in terms of a series of 395 calls to simplistic static methods. This way, we can test as much as 396 possible of the functionality via testing the static methods, while 397 hoping that if the static methods are called appropriately, things will 398 work properly. It's not perfect, but it's much better than no testing at 399 all. 400 401 @sort: __init__, isRewritable, _retrieveProperties, retrieveCapacity, _getBoundaries, 402 _calculateCapacity, openTray, closeTray, refreshMedia, writeImage, 403 _blankMedia, _parsePropertiesOutput, _parseBoundariesOutput, 404 _buildOpenTrayArgs, _buildCloseTrayArgs, _buildPropertiesArgs, 405 _buildBoundariesArgs, _buildBlankArgs, _buildWriteArgs, 406 device, scsiId, hardwareId, driveSpeed, media, deviceType, deviceVendor, 407 deviceId, deviceBufferSize, deviceSupportsMulti, deviceHasTray, deviceCanEject, 408 initializeImage, addImageEntry, writeImage, setImageNewDisc, getEstimatedImageSize 409 """ 410 411 ############## 412 # Constructor 413 ############## 414
415 - def __init__(self, device, scsiId=None, driveSpeed=None, 416 mediaType=MEDIA_CDRW_74, noEject=False, 417 refreshMediaDelay=0, ejectDelay=0, unittest=False):
418 """ 419 Initializes a CD writer object. 420 421 The current user must have write access to the device at the time the 422 object is instantiated, or an exception will be thrown. However, no 423 media-related validation is done, and in fact there is no need for any 424 media to be in the drive until one of the other media attribute-related 425 methods is called. 426 427 The various instance variables such as C{deviceType}, C{deviceVendor}, 428 etc. might be C{None}, if we're unable to parse this specific information 429 from the C{cdrecord} output. This information is just for reference. 430 431 The SCSI id is optional, but the device path is required. If the SCSI id 432 is passed in, then the hardware id attribute will be taken from the SCSI 433 id. Otherwise, the hardware id will be taken from the device. 434 435 If cdrecord improperly detects whether your writer device has a tray and 436 can be safely opened and closed, then pass in C{noEject=False}. This 437 will override the properties and the device will never be ejected. 438 439 @note: The C{unittest} parameter should never be set to C{True} 440 outside of Cedar Backup code. It is intended for use in unit testing 441 Cedar Backup internals and has no other sensible purpose. 442 443 @param device: Filesystem device associated with this writer. 444 @type device: Absolute path to a filesystem device, i.e. C{/dev/cdrw} 445 446 @param scsiId: SCSI id for the device (optional). 447 @type scsiId: If provided, SCSI id in the form C{[<method>:]scsibus,target,lun} 448 449 @param driveSpeed: Speed at which the drive writes. 450 @type driveSpeed: Use C{2} for 2x device, etc. or C{None} to use device default. 451 452 @param mediaType: Type of the media that is assumed to be in the drive. 453 @type mediaType: One of the valid media type as discussed above. 454 455 @param noEject: Overrides properties to indicate that the device does not support eject. 456 @type noEject: Boolean true/false 457 458 @param refreshMediaDelay: Refresh media delay to use, if any 459 @type refreshMediaDelay: Number of seconds, an integer >= 0 460 461 @param ejectDelay: Eject delay to use, if any 462 @type ejectDelay: Number of seconds, an integer >= 0 463 464 @param unittest: Turns off certain validations, for use in unit testing. 465 @type unittest: Boolean true/false 466 467 @raise ValueError: If the device is not valid for some reason. 468 @raise ValueError: If the SCSI id is not in a valid form. 469 @raise ValueError: If the drive speed is not an integer >= 1. 470 @raise IOError: If device properties could not be read for some reason. 471 """ 472 self._image = None # optionally filled in by initializeImage() 473 self._device = validateDevice(device, unittest) 474 self._scsiId = validateScsiId(scsiId) 475 self._driveSpeed = validateDriveSpeed(driveSpeed) 476 self._media = MediaDefinition(mediaType) 477 self._noEject = noEject 478 self._refreshMediaDelay = refreshMediaDelay 479 self._ejectDelay = ejectDelay 480 if not unittest: 481 (self._deviceType, 482 self._deviceVendor, 483 self._deviceId, 484 self._deviceBufferSize, 485 self._deviceSupportsMulti, 486 self._deviceHasTray, 487 self._deviceCanEject) = self._retrieveProperties()
488 489 490 ############# 491 # Properties 492 ############# 493
494 - def _getDevice(self):
495 """ 496 Property target used to get the device value. 497 """ 498 return self._device
499
500 - def _getScsiId(self):
501 """ 502 Property target used to get the SCSI id value. 503 """ 504 return self._scsiId
505
506 - def _getHardwareId(self):
507 """ 508 Property target used to get the hardware id value. 509 """ 510 if self._scsiId is None: 511 return self._device 512 return self._scsiId
513
514 - def _getDriveSpeed(self):
515 """ 516 Property target used to get the drive speed. 517 """ 518 return self._driveSpeed
519
520 - def _getMedia(self):
521 """ 522 Property target used to get the media description. 523 """ 524 return self._media
525
526 - def _getDeviceType(self):
527 """ 528 Property target used to get the device type. 529 """ 530 return self._deviceType
531
532 - def _getDeviceVendor(self):
533 """ 534 Property target used to get the device vendor. 535 """ 536 return self._deviceVendor
537
538 - def _getDeviceId(self):
539 """ 540 Property target used to get the device id. 541 """ 542 return self._deviceId
543
544 - def _getDeviceBufferSize(self):
545 """ 546 Property target used to get the device buffer size. 547 """ 548 return self._deviceBufferSize
549
550 - def _getDeviceSupportsMulti(self):
551 """ 552 Property target used to get the device-support-multi flag. 553 """ 554 return self._deviceSupportsMulti
555
556 - def _getDeviceHasTray(self):
557 """ 558 Property target used to get the device-has-tray flag. 559 """ 560 return self._deviceHasTray
561
562 - def _getDeviceCanEject(self):
563 """ 564 Property target used to get the device-can-eject flag. 565 """ 566 return self._deviceCanEject
567
568 - def _getRefreshMediaDelay(self):
569 """ 570 Property target used to get the configured refresh media delay, in seconds. 571 """ 572 return self._refreshMediaDelay
573
574 - def _getEjectDelay(self):
575 """ 576 Property target used to get the configured eject delay, in seconds. 577 """ 578 return self._ejectDelay
579 580 device = property(_getDevice, None, None, doc="Filesystem device name for this writer.") 581 scsiId = property(_getScsiId, None, None, doc="SCSI id for the device, in the form C{[<method>:]scsibus,target,lun}.") 582 hardwareId = property(_getHardwareId, None, None, doc="Hardware id for this writer, either SCSI id or device path.") 583 driveSpeed = property(_getDriveSpeed, None, None, doc="Speed at which the drive writes.") 584 media = property(_getMedia, None, None, doc="Definition of media that is expected to be in the device.") 585 deviceType = property(_getDeviceType, None, None, doc="Type of the device, as returned from C{cdrecord -prcap}.") 586 deviceVendor = property(_getDeviceVendor, None, None, doc="Vendor of the device, as returned from C{cdrecord -prcap}.") 587 deviceId = property(_getDeviceId, None, None, doc="Device identification, as returned from C{cdrecord -prcap}.") 588 deviceBufferSize = property(_getDeviceBufferSize, None, None, doc="Size of the device's write buffer, in bytes.") 589 deviceSupportsMulti = property(_getDeviceSupportsMulti, None, None, doc="Indicates whether device supports multisession discs.") 590 deviceHasTray = property(_getDeviceHasTray, None, None, doc="Indicates whether the device has a media tray.") 591 deviceCanEject = property(_getDeviceCanEject, None, None, doc="Indicates whether the device supports ejecting its media.") 592 refreshMediaDelay = property(_getRefreshMediaDelay, None, None, doc="Refresh media delay, in seconds.") 593 ejectDelay = property(_getEjectDelay, None, None, doc="Eject delay, in seconds.") 594 595 596 ################################################# 597 # Methods related to device and media attributes 598 ################################################# 599
600 - def isRewritable(self):
601 """Indicates whether the media is rewritable per configuration.""" 602 return self._media.rewritable
603
604 - def _retrieveProperties(self):
605 """ 606 Retrieves properties for a device from C{cdrecord}. 607 608 The results are returned as a tuple of the object device attributes as 609 returned from L{_parsePropertiesOutput}: C{(deviceType, deviceVendor, 610 deviceId, deviceBufferSize, deviceSupportsMulti, deviceHasTray, 611 deviceCanEject)}. 612 613 @return: Results tuple as described above. 614 @raise IOError: If there is a problem talking to the device. 615 """ 616 args = CdWriter._buildPropertiesArgs(self.hardwareId) 617 command = resolveCommand(CDRECORD_COMMAND) 618 (result, output) = executeCommand(command, args, returnOutput=True, ignoreStderr=True) 619 if result != 0: 620 raise IOError("Error (%d) executing cdrecord command to get properties." % result) 621 return CdWriter._parsePropertiesOutput(output)
622
623 - def retrieveCapacity(self, entireDisc=False, useMulti=True):
624 """ 625 Retrieves capacity for the current media in terms of a C{MediaCapacity} 626 object. 627 628 If C{entireDisc} is passed in as C{True} the capacity will be for the 629 entire disc, as if it were to be rewritten from scratch. If the drive 630 does not support writing multisession discs or if C{useMulti} is passed 631 in as C{False}, the capacity will also be as if the disc were to be 632 rewritten from scratch, but the indicated boundaries value will be 633 C{None}. The same will happen if the disc cannot be read for some 634 reason. Otherwise, the capacity (including the boundaries) will 635 represent whatever space remains on the disc to be filled by future 636 sessions. 637 638 @param entireDisc: Indicates whether to return capacity for entire disc. 639 @type entireDisc: Boolean true/false 640 641 @param useMulti: Indicates whether a multisession disc should be assumed, if possible. 642 @type useMulti: Boolean true/false 643 644 @return: C{MediaCapacity} object describing the capacity of the media. 645 @raise IOError: If the media could not be read for some reason. 646 """ 647 boundaries = self._getBoundaries(entireDisc, useMulti) 648 return CdWriter._calculateCapacity(self._media, boundaries)
649
650 - def _getBoundaries(self, entireDisc=False, useMulti=True):
651 """ 652 Gets the ISO boundaries for the media. 653 654 If C{entireDisc} is passed in as C{True} the boundaries will be C{None}, 655 as if the disc were to be rewritten from scratch. If the drive does not 656 support writing multisession discs, the returned value will be C{None}. 657 The same will happen if the disc can't be read for some reason. 658 Otherwise, the returned value will be represent the boundaries of the 659 disc's current contents. 660 661 The results are returned as a tuple of (lower, upper) as needed by the 662 C{IsoImage} class. Note that these values are in terms of ISO sectors, 663 not bytes. Clients should generally consider the boundaries value 664 opaque, however. 665 666 @param entireDisc: Indicates whether to return capacity for entire disc. 667 @type entireDisc: Boolean true/false 668 669 @param useMulti: Indicates whether a multisession disc should be assumed, if possible. 670 @type useMulti: Boolean true/false 671 672 @return: Boundaries tuple or C{None}, as described above. 673 @raise IOError: If the media could not be read for some reason. 674 """ 675 if not self._deviceSupportsMulti: 676 logger.debug("Device does not support multisession discs; returning boundaries None.") 677 return None 678 elif not useMulti: 679 logger.debug("Use multisession flag is False; returning boundaries None.") 680 return None 681 elif entireDisc: 682 logger.debug("Entire disc flag is True; returning boundaries None.") 683 return None 684 else: 685 args = CdWriter._buildBoundariesArgs(self.hardwareId) 686 command = resolveCommand(CDRECORD_COMMAND) 687 (result, output) = executeCommand(command, args, returnOutput=True, ignoreStderr=True) 688 if result != 0: 689 logger.debug("Error (%d) executing cdrecord command to get capacity." % result) 690 logger.warn("Unable to read disc (might not be initialized); returning boundaries of None.") 691 return None 692 boundaries = CdWriter._parseBoundariesOutput(output) 693 if boundaries is None: 694 logger.debug("Returning disc boundaries: None") 695 else: 696 logger.debug("Returning disc boundaries: (%d, %d)" % (boundaries[0], boundaries[1])) 697 return boundaries
698 699 @staticmethod
700 - def _calculateCapacity(media, boundaries):
701 """ 702 Calculates capacity for the media in terms of boundaries. 703 704 If C{boundaries} is C{None} or the lower bound is 0 (zero), then the 705 capacity will be for the entire disc minus the initial lead in. 706 Otherwise, capacity will be as if the caller wanted to add an additional 707 session to the end of the existing data on the disc. 708 709 @param media: MediaDescription object describing the media capacity. 710 @param boundaries: Session boundaries as returned from L{_getBoundaries}. 711 712 @return: C{MediaCapacity} object describing the capacity of the media. 713 """ 714 if boundaries is None or boundaries[1] == 0: 715 logger.debug("Capacity calculations are based on a complete disc rewrite.") 716 sectorsAvailable = media.capacity - media.initialLeadIn 717 if sectorsAvailable < 0: sectorsAvailable = 0 718 bytesUsed = 0 719 bytesAvailable = convertSize(sectorsAvailable, UNIT_SECTORS, UNIT_BYTES) 720 else: 721 logger.debug("Capacity calculations are based on a new ISO session.") 722 sectorsAvailable = media.capacity - boundaries[1] - media.leadIn 723 if sectorsAvailable < 0: sectorsAvailable = 0 724 bytesUsed = convertSize(boundaries[1], UNIT_SECTORS, UNIT_BYTES) 725 bytesAvailable = convertSize(sectorsAvailable, UNIT_SECTORS, UNIT_BYTES) 726 logger.debug("Used [%s], available [%s]." % (displayBytes(bytesUsed), displayBytes(bytesAvailable))) 727 return MediaCapacity(bytesUsed, bytesAvailable, boundaries)
728 729 730 ####################################################### 731 # Methods used for working with the internal ISO image 732 ####################################################### 733
734 - def initializeImage(self, newDisc, tmpdir, mediaLabel=None):
735 """ 736 Initializes the writer's associated ISO image. 737 738 This method initializes the C{image} instance variable so that the caller 739 can use the C{addImageEntry} method. Once entries have been added, the 740 C{writeImage} method can be called with no arguments. 741 742 @param newDisc: Indicates whether the disc should be re-initialized 743 @type newDisc: Boolean true/false. 744 745 @param tmpdir: Temporary directory to use if needed 746 @type tmpdir: String representing a directory path on disk 747 748 @param mediaLabel: Media label to be applied to the image, if any 749 @type mediaLabel: String, no more than 25 characters long 750 """ 751 self._image = _ImageProperties() 752 self._image.newDisc = newDisc 753 self._image.tmpdir = encodePath(tmpdir) 754 self._image.mediaLabel = mediaLabel 755 self._image.entries = {} # mapping from path to graft point (if any)
756
757 - def addImageEntry(self, path, graftPoint):
758 """ 759 Adds a filepath entry to the writer's associated ISO image. 760 761 The contents of the filepath -- but not the path itself -- will be added 762 to the image at the indicated graft point. If you don't want to use a 763 graft point, just pass C{None}. 764 765 @note: Before calling this method, you must call L{initializeImage}. 766 767 @param path: File or directory to be added to the image 768 @type path: String representing a path on disk 769 770 @param graftPoint: Graft point to be used when adding this entry 771 @type graftPoint: String representing a graft point path, as described above 772 773 @raise ValueError: If initializeImage() was not previously called 774 """ 775 if self._image is None: 776 raise ValueError("Must call initializeImage() before using this method.") 777 if not os.path.exists(path): 778 raise ValueError("Path [%s] does not exist." % path) 779 self._image.entries[path] = graftPoint
780
781 - def setImageNewDisc(self, newDisc):
782 """ 783 Resets (overrides) the newDisc flag on the internal image. 784 @param newDisc: New disc flag to set 785 @raise ValueError: If initializeImage() was not previously called 786 """ 787 if self._image is None: 788 raise ValueError("Must call initializeImage() before using this method.") 789 self._image.newDisc = newDisc
790
791 - def getEstimatedImageSize(self):
792 """ 793 Gets the estimated size of the image associated with the writer. 794 @return: Estimated size of the image, in bytes. 795 @raise IOError: If there is a problem calling C{mkisofs}. 796 @raise ValueError: If initializeImage() was not previously called 797 """ 798 if self._image is None: 799 raise ValueError("Must call initializeImage() before using this method.") 800 image = IsoImage() 801 for path in self._image.entries.keys(): 802 image.addEntry(path, self._image.entries[path], override=False, contentsOnly=True) 803 return image.getEstimatedSize()
804 805 806 ###################################### 807 # Methods which expose device actions 808 ###################################### 809
810 - def openTray(self):
811 """ 812 Opens the device's tray and leaves it open. 813 814 This only works if the device has a tray and supports ejecting its media. 815 We have no way to know if the tray is currently open or closed, so we 816 just send the appropriate command and hope for the best. If the device 817 does not have a tray or does not support ejecting its media, then we do 818 nothing. 819 820 If the writer was constructed with C{noEject=True}, then this is a no-op. 821 822 Starting with Debian wheezy on my backup hardware, I started seeing 823 consistent problems with the eject command. I couldn't tell whether 824 these problems were due to the device management system or to the new 825 kernel (3.2.0). Initially, I saw simple eject failures, possibly because 826 I was opening and closing the tray too quickly. I worked around that 827 behavior with the new ejectDelay flag. 828 829 Later, I sometimes ran into issues after writing an image to a disc: 830 eject would give errors like "unable to eject, last error: Inappropriate 831 ioctl for device". Various sources online (like Ubuntu bug #875543) 832 suggested that the drive was being locked somehow, and that the 833 workaround was to run 'eject -i off' to unlock it. Sure enough, that 834 fixed the problem for me, so now it's a normal error-handling strategy. 835 836 @raise IOError: If there is an error talking to the device. 837 """ 838 if not self._noEject: 839 if self._deviceHasTray and self._deviceCanEject: 840 args = CdWriter._buildOpenTrayArgs(self._device) 841 result = executeCommand(EJECT_COMMAND, args)[0] 842 if result != 0: 843 logger.debug("Eject failed; attempting kludge of unlocking the tray before retrying.") 844 self.unlockTray() 845 result = executeCommand(EJECT_COMMAND, args)[0] 846 if result != 0: 847 raise IOError("Error (%d) executing eject command to open tray (failed even after unlocking tray)." % result) 848 logger.debug("Kludge was apparently successful.") 849 if self.ejectDelay is not None: 850 logger.debug("Per configuration, sleeping %d seconds after opening tray." % self.ejectDelay) 851 time.sleep(self.ejectDelay)
852
853 - def unlockTray(self):
854 """ 855 Unlocks the device's tray. 856 @raise IOError: If there is an error talking to the device. 857 """ 858 args = CdWriter._buildUnlockTrayArgs(self._device) 859 command = resolveCommand(EJECT_COMMAND) 860 result = executeCommand(command, args)[0] 861 if result != 0: 862 raise IOError("Error (%d) executing eject command to unlock tray." % result)
863
864 - def closeTray(self):
865 """ 866 Closes the device's tray. 867 868 This only works if the device has a tray and supports ejecting its media. 869 We have no way to know if the tray is currently open or closed, so we 870 just send the appropriate command and hope for the best. If the device 871 does not have a tray or does not support ejecting its media, then we do 872 nothing. 873 874 If the writer was constructed with C{noEject=True}, then this is a no-op. 875 876 @raise IOError: If there is an error talking to the device. 877 """ 878 if not self._noEject: 879 if self._deviceHasTray and self._deviceCanEject: 880 args = CdWriter._buildCloseTrayArgs(self._device) 881 command = resolveCommand(EJECT_COMMAND) 882 result = executeCommand(command, args)[0] 883 if result != 0: 884 raise IOError("Error (%d) executing eject command to close tray." % result)
885
886 - def refreshMedia(self):
887 """ 888 Opens and then immediately closes the device's tray, to refresh the 889 device's idea of the media. 890 891 Sometimes, a device gets confused about the state of its media. Often, 892 all it takes to solve the problem is to eject the media and then 893 immediately reload it. (There are also configurable eject and refresh 894 media delays which can be applied, for situations where this makes a 895 difference.) 896 897 This only works if the device has a tray and supports ejecting its media. 898 We have no way to know if the tray is currently open or closed, so we 899 just send the appropriate command and hope for the best. If the device 900 does not have a tray or does not support ejecting its media, then we do 901 nothing. The configured delays still apply, though. 902 903 @raise IOError: If there is an error talking to the device. 904 """ 905 self.openTray() 906 self.closeTray() 907 self.unlockTray() # on some systems, writing a disc leaves the tray locked, yikes! 908 if self.refreshMediaDelay is not None: 909 logger.debug("Per configuration, sleeping %d seconds to stabilize media state." % self.refreshMediaDelay) 910 time.sleep(self.refreshMediaDelay) 911 logger.debug("Media refresh complete; hopefully media state is stable now.")
912
913 - def writeImage(self, imagePath=None, newDisc=False, writeMulti=True):
914 """ 915 Writes an ISO image to the media in the device. 916 917 If C{newDisc} is passed in as C{True}, we assume that the entire disc 918 will be overwritten, and the media will be blanked before writing it if 919 possible (i.e. if the media is rewritable). 920 921 If C{writeMulti} is passed in as C{True}, then a multisession disc will 922 be written if possible (i.e. if the drive supports writing multisession 923 discs). 924 925 if C{imagePath} is passed in as C{None}, then the existing image 926 configured with C{initializeImage} will be used. Under these 927 circumstances, the passed-in C{newDisc} flag will be ignored. 928 929 By default, we assume that the disc can be written multisession and that 930 we should append to the current contents of the disc. In any case, the 931 ISO image must be generated appropriately (i.e. must take into account 932 any existing session boundaries, etc.) 933 934 @param imagePath: Path to an ISO image on disk, or C{None} to use writer's image 935 @type imagePath: String representing a path on disk 936 937 @param newDisc: Indicates whether the entire disc will overwritten. 938 @type newDisc: Boolean true/false. 939 940 @param writeMulti: Indicates whether a multisession disc should be written, if possible. 941 @type writeMulti: Boolean true/false 942 943 @raise ValueError: If the image path is not absolute. 944 @raise ValueError: If some path cannot be encoded properly. 945 @raise IOError: If the media could not be written to for some reason. 946 @raise ValueError: If no image is passed in and initializeImage() was not previously called 947 """ 948 if imagePath is None: 949 if self._image is None: 950 raise ValueError("Must call initializeImage() before using this method with no image path.") 951 try: 952 imagePath = self._createImage() 953 self._writeImage(imagePath, writeMulti, self._image.newDisc) 954 finally: 955 if imagePath is not None and os.path.exists(imagePath): 956 try: os.unlink(imagePath) 957 except: pass 958 else: 959 imagePath = encodePath(imagePath) 960 if not os.path.isabs(imagePath): 961 raise ValueError("Image path must be absolute.") 962 self._writeImage(imagePath, writeMulti, newDisc)
963
964 - def _createImage(self):
965 """ 966 Creates an ISO image based on configuration in self._image. 967 @return: Path to the newly-created ISO image on disk. 968 @raise IOError: If there is an error writing the image to disk. 969 @raise ValueError: If there are no filesystem entries in the image 970 @raise ValueError: If a path cannot be encoded properly. 971 """ 972 path = None 973 capacity = self.retrieveCapacity(entireDisc=self._image.newDisc) 974 image = IsoImage(self.device, capacity.boundaries) 975 image.volumeId = self._image.mediaLabel # may be None, which is also valid 976 for key in self._image.entries.keys(): 977 image.addEntry(key, self._image.entries[key], override=False, contentsOnly=True) 978 size = image.getEstimatedSize() 979 logger.info("Image size will be %s." % displayBytes(size)) 980 available = capacity.bytesAvailable 981 logger.debug("Media capacity: %s" % displayBytes(available)) 982 if size > available: 983 logger.error("Image [%s] does not fit in available capacity [%s]." % (displayBytes(size), displayBytes(available))) 984 raise IOError("Media does not contain enough capacity to store image.") 985 try: 986 (handle, path) = tempfile.mkstemp(dir=self._image.tmpdir) 987 try: os.close(handle) 988 except: pass 989 image.writeImage(path) 990 logger.debug("Completed creating image [%s]." % path) 991 return path 992 except Exception, e: 993 if path is not None and os.path.exists(path): 994 try: os.unlink(path) 995 except: pass 996 raise e
997
998 - def _writeImage(self, imagePath, writeMulti, newDisc):
999 """ 1000 Write an ISO image to disc using cdrecord. 1001 The disc is blanked first if C{newDisc} is C{True}. 1002 @param imagePath: Path to an ISO image on disk 1003 @param writeMulti: Indicates whether a multisession disc should be written, if possible. 1004 @param newDisc: Indicates whether the entire disc will overwritten. 1005 """ 1006 if newDisc: 1007 self._blankMedia() 1008 args = CdWriter._buildWriteArgs(self.hardwareId, imagePath, self._driveSpeed, writeMulti and self._deviceSupportsMulti) 1009 command = resolveCommand(CDRECORD_COMMAND) 1010 result = executeCommand(command, args)[0] 1011 if result != 0: 1012 raise IOError("Error (%d) executing command to write disc." % result) 1013 self.refreshMedia()
1014
1015 - def _blankMedia(self):
1016 """ 1017 Blanks the media in the device, if the media is rewritable. 1018 @raise IOError: If the media could not be written to for some reason. 1019 """ 1020 if self.isRewritable(): 1021 args = CdWriter._buildBlankArgs(self.hardwareId) 1022 command = resolveCommand(CDRECORD_COMMAND) 1023 result = executeCommand(command, args)[0] 1024 if result != 0: 1025 raise IOError("Error (%d) executing command to blank disc." % result) 1026 self.refreshMedia()
1027 1028 1029 ####################################### 1030 # Methods used to parse command output 1031 ####################################### 1032 1033 @staticmethod
1034 - def _parsePropertiesOutput(output):
1035 """ 1036 Parses the output from a C{cdrecord} properties command. 1037 1038 The C{output} parameter should be a list of strings as returned from 1039 C{executeCommand} for a C{cdrecord} command with arguments as from 1040 C{_buildPropertiesArgs}. The list of strings will be parsed to yield 1041 information about the properties of the device. 1042 1043 The output is expected to be a huge long list of strings. Unfortunately, 1044 the strings aren't in a completely regular format. However, the format 1045 of individual lines seems to be regular enough that we can look for 1046 specific values. Two kinds of parsing take place: one kind of parsing 1047 picks out out specific values like the device id, device vendor, etc. 1048 The other kind of parsing just sets a boolean flag C{True} if a matching 1049 line is found. All of the parsing is done with regular expressions. 1050 1051 Right now, pretty much nothing in the output is required and we should 1052 parse an empty document successfully (albeit resulting in a device that 1053 can't eject, doesn't have a tray and doesnt't support multisession 1054 discs). I had briefly considered erroring out if certain lines weren't 1055 found or couldn't be parsed, but that seems like a bad idea given that 1056 most of the information is just for reference. 1057 1058 The results are returned as a tuple of the object device attributes: 1059 C{(deviceType, deviceVendor, deviceId, deviceBufferSize, 1060 deviceSupportsMulti, deviceHasTray, deviceCanEject)}. 1061 1062 @param output: Output from a C{cdrecord -prcap} command. 1063 1064 @return: Results tuple as described above. 1065 @raise IOError: If there is problem parsing the output. 1066 """ 1067 deviceType = None 1068 deviceVendor = None 1069 deviceId = None 1070 deviceBufferSize = None 1071 deviceSupportsMulti = False 1072 deviceHasTray = False 1073 deviceCanEject = False 1074 typePattern = re.compile(r"(^Device type\s*:\s*)(.*)(\s*)(.*$)") 1075 vendorPattern = re.compile(r"(^Vendor_info\s*:\s*'\s*)(.*?)(\s*')(.*$)") 1076 idPattern = re.compile(r"(^Identifikation\s*:\s*'\s*)(.*?)(\s*')(.*$)") 1077 bufferPattern = re.compile(r"(^\s*Buffer size in KB:\s*)(.*?)(\s*$)") 1078 multiPattern = re.compile(r"^\s*Does read multi-session.*$") 1079 trayPattern = re.compile(r"^\s*Loading mechanism type: tray.*$") 1080 ejectPattern = re.compile(r"^\s*Does support ejection.*$") 1081 for line in output: 1082 if typePattern.search(line): 1083 deviceType = typePattern.search(line).group(2) 1084 logger.info("Device type is [%s]." % deviceType) 1085 elif vendorPattern.search(line): 1086 deviceVendor = vendorPattern.search(line).group(2) 1087 logger.info("Device vendor is [%s]." % deviceVendor) 1088 elif idPattern.search(line): 1089 deviceId = idPattern.search(line).group(2) 1090 logger.info("Device id is [%s]." % deviceId) 1091 elif bufferPattern.search(line): 1092 try: 1093 sectors = int(bufferPattern.search(line).group(2)) 1094 deviceBufferSize = convertSize(sectors, UNIT_KBYTES, UNIT_BYTES) 1095 logger.info("Device buffer size is [%d] bytes." % deviceBufferSize) 1096 except TypeError: pass 1097 elif multiPattern.search(line): 1098 deviceSupportsMulti = True 1099 logger.info("Device does support multisession discs.") 1100 elif trayPattern.search(line): 1101 deviceHasTray = True 1102 logger.info("Device has a tray.") 1103 elif ejectPattern.search(line): 1104 deviceCanEject = True 1105 logger.info("Device can eject its media.") 1106 return (deviceType, deviceVendor, deviceId, deviceBufferSize, deviceSupportsMulti, deviceHasTray, deviceCanEject)
1107 1108 @staticmethod
1109 - def _parseBoundariesOutput(output):
1110 """ 1111 Parses the output from a C{cdrecord} capacity command. 1112 1113 The C{output} parameter should be a list of strings as returned from 1114 C{executeCommand} for a C{cdrecord} command with arguments as from 1115 C{_buildBoundaryArgs}. The list of strings will be parsed to yield 1116 information about the capacity of the media in the device. 1117 1118 Basically, we expect the list of strings to include just one line, a pair 1119 of values. There isn't supposed to be whitespace, but we allow it anyway 1120 in the regular expression. Any lines below the one line we parse are 1121 completely ignored. It would be a good idea to ignore C{stderr} when 1122 executing the C{cdrecord} command that generates output for this method, 1123 because sometimes C{cdrecord} spits out kernel warnings about the actual 1124 output. 1125 1126 The results are returned as a tuple of (lower, upper) as needed by the 1127 C{IsoImage} class. Note that these values are in terms of ISO sectors, 1128 not bytes. Clients should generally consider the boundaries value 1129 opaque, however. 1130 1131 @note: If the boundaries output can't be parsed, we return C{None}. 1132 1133 @param output: Output from a C{cdrecord -msinfo} command. 1134 1135 @return: Boundaries tuple as described above. 1136 @raise IOError: If there is problem parsing the output. 1137 """ 1138 if len(output) < 1: 1139 logger.warn("Unable to read disc (might not be initialized); returning full capacity.") 1140 return None 1141 boundaryPattern = re.compile(r"(^\s*)([0-9]*)(\s*,\s*)([0-9]*)(\s*$)") 1142 parsed = boundaryPattern.search(output[0]) 1143 if not parsed: 1144 raise IOError("Unable to parse output of boundaries command.") 1145 try: 1146 boundaries = ( int(parsed.group(2)), int(parsed.group(4)) ) 1147 except TypeError: 1148 raise IOError("Unable to parse output of boundaries command.") 1149 return boundaries
1150 1151 1152 ################################# 1153 # Methods used to build commands 1154 ################################# 1155 1156 @staticmethod
1157 - def _buildOpenTrayArgs(device):
1158 """ 1159 Builds a list of arguments to be passed to a C{eject} command. 1160 1161 The arguments will cause the C{eject} command to open the tray and 1162 eject the media. No validation is done by this method as to whether 1163 this action actually makes sense. 1164 1165 @param device: Filesystem device name for this writer, i.e. C{/dev/cdrw}. 1166 1167 @return: List suitable for passing to L{util.executeCommand} as C{args}. 1168 """ 1169 args = [] 1170 args.append(device) 1171 return args
1172 1173 @staticmethod
1174 - def _buildUnlockTrayArgs(device):
1175 """ 1176 Builds a list of arguments to be passed to a C{eject} command. 1177 1178 The arguments will cause the C{eject} command to unlock the tray. 1179 1180 @param device: Filesystem device name for this writer, i.e. C{/dev/cdrw}. 1181 1182 @return: List suitable for passing to L{util.executeCommand} as C{args}. 1183 """ 1184 args = [] 1185 args.append("-i") 1186 args.append("off") 1187 args.append(device) 1188 return args
1189 1190 @staticmethod
1191 - def _buildCloseTrayArgs(device):
1192 """ 1193 Builds a list of arguments to be passed to a C{eject} command. 1194 1195 The arguments will cause the C{eject} command to close the tray and reload 1196 the media. No validation is done by this method as to whether this 1197 action actually makes sense. 1198 1199 @param device: Filesystem device name for this writer, i.e. C{/dev/cdrw}. 1200 1201 @return: List suitable for passing to L{util.executeCommand} as C{args}. 1202 """ 1203 args = [] 1204 args.append("-t") 1205 args.append(device) 1206 return args
1207 1208 @staticmethod
1209 - def _buildPropertiesArgs(hardwareId):
1210 """ 1211 Builds a list of arguments to be passed to a C{cdrecord} command. 1212 1213 The arguments will cause the C{cdrecord} command to ask the device 1214 for a list of its capacities via the C{-prcap} switch. 1215 1216 @param hardwareId: Hardware id for the device (either SCSI id or device path) 1217 1218 @return: List suitable for passing to L{util.executeCommand} as C{args}. 1219 """ 1220 args = [] 1221 args.append("-prcap") 1222 args.append("dev=%s" % hardwareId) 1223 return args
1224 1225 @staticmethod
1226 - def _buildBoundariesArgs(hardwareId):
1227 """ 1228 Builds a list of arguments to be passed to a C{cdrecord} command. 1229 1230 The arguments will cause the C{cdrecord} command to ask the device for 1231 the current multisession boundaries of the media using the C{-msinfo} 1232 switch. 1233 1234 @param hardwareId: Hardware id for the device (either SCSI id or device path) 1235 1236 @return: List suitable for passing to L{util.executeCommand} as C{args}. 1237 """ 1238 args = [] 1239 args.append("-msinfo") 1240 args.append("dev=%s" % hardwareId) 1241 return args
1242 1243 @staticmethod
1244 - def _buildBlankArgs(hardwareId, driveSpeed=None):
1245 """ 1246 Builds a list of arguments to be passed to a C{cdrecord} command. 1247 1248 The arguments will cause the C{cdrecord} command to blank the media in 1249 the device identified by C{hardwareId}. No validation is done by this method 1250 as to whether the action makes sense (i.e. to whether the media even can 1251 be blanked). 1252 1253 @param hardwareId: Hardware id for the device (either SCSI id or device path) 1254 @param driveSpeed: Speed at which the drive writes. 1255 1256 @return: List suitable for passing to L{util.executeCommand} as C{args}. 1257 """ 1258 args = [] 1259 args.append("-v") 1260 args.append("blank=fast") 1261 if driveSpeed is not None: 1262 args.append("speed=%d" % driveSpeed) 1263 args.append("dev=%s" % hardwareId) 1264 return args
1265 1266 @staticmethod
1267 - def _buildWriteArgs(hardwareId, imagePath, driveSpeed=None, writeMulti=True):
1268 """ 1269 Builds a list of arguments to be passed to a C{cdrecord} command. 1270 1271 The arguments will cause the C{cdrecord} command to write the indicated 1272 ISO image (C{imagePath}) to the media in the device identified by 1273 C{hardwareId}. The C{writeMulti} argument controls whether to write a 1274 multisession disc. No validation is done by this method as to whether 1275 the action makes sense (i.e. to whether the device even can write 1276 multisession discs, for instance). 1277 1278 @param hardwareId: Hardware id for the device (either SCSI id or device path) 1279 @param imagePath: Path to an ISO image on disk. 1280 @param driveSpeed: Speed at which the drive writes. 1281 @param writeMulti: Indicates whether to write a multisession disc. 1282 1283 @return: List suitable for passing to L{util.executeCommand} as C{args}. 1284 """ 1285 args = [] 1286 args.append("-v") 1287 if driveSpeed is not None: 1288 args.append("speed=%d" % driveSpeed) 1289 args.append("dev=%s" % hardwareId) 1290 if writeMulti: 1291 args.append("-multi") 1292 args.append("-data") 1293 args.append(imagePath) 1294 return args
1295