scripts/analyze-migration.py

   1 #!/usr/bin/env python3
   2 #
   3 #  Migration Stream Analyzer
   4 #
   5 #  Copyright (c) 2015 Alexander Graf <agraf@suse.de>
   6 #
   7 # This library is free software; you can redistribute it and/or
   8 # modify it under the terms of the GNU Lesser General Public
   9 # License as published by the Free Software Foundation; either
  10 # version 2.1 of the License, or (at your option) any later version.
  11 #
  12 # This library is distributed in the hope that it will be useful,
  13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 # Lesser General Public License for more details.
  16 #
  17 # You should have received a copy of the GNU Lesser General Public
  18 # License along with this library; if not, see <http://www.gnu.org/licenses/>.
  19
  20 import json
  21 import os
  22 import argparse
  23 import collections
  24 import struct
  25 import sys
  26
  27
  28 def mkdir_p(path):
  29     try:
  30         os.makedirs(path)
  31     except OSError:
  32         pass
  33
  34
  35 class MigrationFile(object):
  36     def __init__(self, filename):
  37         self.filename = filename
  38         self.file = open(self.filename, "rb")
  39
  40     def read64(self):
  41         return int.from_bytes(self.file.read(8), byteorder='big', signed=False)
  42
  43     def read32(self):
  44         return int.from_bytes(self.file.read(4), byteorder='big', signed=False)
  45
  46     def read16(self):
  47         return int.from_bytes(self.file.read(2), byteorder='big', signed=False)
  48
  49     def read8(self):
  50         return int.from_bytes(self.file.read(1), byteorder='big', signed=True)
  51
  52     def readstr(self, len = None):
  53         return self.readvar(len).decode('utf-8')
  54
  55     def readvar(self, size = None):
  56         if size is None:
  57             size = self.read8()
  58         if size == 0:
  59             return ""
  60         value = self.file.read(size)
  61         if len(value) != size:
  62             raise Exception("Unexpected end of %s at 0x%x" % (self.filename, self.file.tell()))
  63         return value
  64
  65     def tell(self):
  66         return self.file.tell()
  67
  68     # The VMSD description is at the end of the file, after EOF. Look for
  69     # the last NULL byte, then for the beginning brace of JSON.
  70     def read_migration_debug_json(self):
  71         QEMU_VM_VMDESCRIPTION = 0x06
  72
  73         # Remember the offset in the file when we started
  74         entrypos = self.file.tell()
  75
  76         # Read the last 10MB
  77         self.file.seek(0, os.SEEK_END)
  78         endpos = self.file.tell()
  79         self.file.seek(max(-endpos, -10 * 1024 * 1024), os.SEEK_END)
  80         datapos = self.file.tell()
  81         data = self.file.read()
  82         # The full file read closed the file as well, reopen it
  83         self.file = open(self.filename, "rb")
  84
  85         # Find the last NULL byte, then the first brace after that. This should
  86         # be the beginning of our JSON data.
  87         nulpos = data.rfind(b'\0')
  88         jsonpos = data.find(b'{', nulpos)
  89
  90         # Check backwards from there and see whether we guessed right
  91         self.file.seek(datapos + jsonpos - 5, 0)
  92         if self.read8() != QEMU_VM_VMDESCRIPTION:
  93             raise Exception("No Debug Migration device found")
  94
  95         jsonlen = self.read32()
  96
  97         # Seek back to where we were at the beginning
  98         self.file.seek(entrypos, 0)
  99
 100         # explicit decode() needed for Python 3.5 compatibility
 101         return data[jsonpos:jsonpos + jsonlen].decode("utf-8")
 102
 103     def close(self):
 104         self.file.close()
 105
 106 class RamSection(object):
 107     RAM_SAVE_FLAG_COMPRESS = 0x02
 108     RAM_SAVE_FLAG_MEM_SIZE = 0x04
 109     RAM_SAVE_FLAG_PAGE     = 0x08
 110     RAM_SAVE_FLAG_EOS      = 0x10
 111     RAM_SAVE_FLAG_CONTINUE = 0x20
 112     RAM_SAVE_FLAG_XBZRLE   = 0x40
 113     RAM_SAVE_FLAG_HOOK     = 0x80
 114     RAM_SAVE_FLAG_COMPRESS_PAGE = 0x100
 115     RAM_SAVE_FLAG_MULTIFD_FLUSH = 0x200
 116
 117     def __init__(self, file, version_id, ramargs, section_key):
 118         if version_id != 4:
 119             raise Exception("Unknown RAM version %d" % version_id)
 120
 121         self.file = file
 122         self.section_key = section_key
 123         self.TARGET_PAGE_SIZE = ramargs['page_size']
 124         self.dump_memory = ramargs['dump_memory']
 125         self.write_memory = ramargs['write_memory']
 126         self.ignore_shared = ramargs['ignore_shared']
 127         self.sizeinfo = collections.OrderedDict()
 128         self.data = collections.OrderedDict()
 129         self.data['section sizes'] = self.sizeinfo
 130         self.name = ''
 131         if self.write_memory:
 132             self.files = { }
 133         if self.dump_memory:
 134             self.memory = collections.OrderedDict()
 135             self.data['memory'] = self.memory
 136
 137     def __repr__(self):
 138         return self.data.__repr__()
 139
 140     def __str__(self):
 141         return self.data.__str__()
 142
 143     def getDict(self):
 144         return self.data
 145
 146     def read(self):
 147         # Read all RAM sections
 148         while True:
 149             addr = self.file.read64()
 150             flags = addr & (self.TARGET_PAGE_SIZE - 1)
 151             addr &= ~(self.TARGET_PAGE_SIZE - 1)
 152
 153             if flags & self.RAM_SAVE_FLAG_MEM_SIZE:
 154                 total_length = addr
 155                 while total_length > 0:
 156                     namelen = self.file.read8()
 157                     self.name = self.file.readstr(len = namelen)
 158                     len = self.file.read64()
 159                     total_length -= len
 160                     self.sizeinfo[self.name] = '0x%016x' % len
 161                     if self.write_memory:
 162                         print(self.name)
 163                         mkdir_p('./' + os.path.dirname(self.name))
 164                         f = open('./' + self.name, "wb")
 165                         f.truncate(0)
 166                         f.truncate(len)
 167                         self.files[self.name] = f
 168                     if self.ignore_shared:
 169                         mr_addr = self.file.read64()
 170                 flags &= ~self.RAM_SAVE_FLAG_MEM_SIZE
 171
 172             if flags & self.RAM_SAVE_FLAG_COMPRESS:
 173                 if flags & self.RAM_SAVE_FLAG_CONTINUE:
 174                     flags &= ~self.RAM_SAVE_FLAG_CONTINUE
 175                 else:
 176                     self.name = self.file.readstr()
 177                 fill_char = self.file.read8()
 178                 # The page in question is filled with fill_char now
 179                 if self.write_memory and fill_char != 0:
 180                     self.files[self.name].seek(addr, os.SEEK_SET)
 181                     self.files[self.name].write(chr(fill_char) * self.TARGET_PAGE_SIZE)
 182                 if self.dump_memory:
 183                     self.memory['%s (0x%016x)' % (self.name, addr)] = 'Filled with 0x%02x' % fill_char
 184                 flags &= ~self.RAM_SAVE_FLAG_COMPRESS
 185             elif flags & self.RAM_SAVE_FLAG_PAGE:
 186                 if flags & self.RAM_SAVE_FLAG_CONTINUE:
 187                     flags &= ~self.RAM_SAVE_FLAG_CONTINUE
 188                 else:
 189                     self.name = self.file.readstr()
 190
 191                 if self.write_memory or self.dump_memory:
 192                     data = self.file.readvar(size = self.TARGET_PAGE_SIZE)
 193                 else: # Just skip RAM data
 194                     self.file.file.seek(self.TARGET_PAGE_SIZE, 1)
 195
 196                 if self.write_memory:
 197                     self.files[self.name].seek(addr, os.SEEK_SET)
 198                     self.files[self.name].write(data)
 199                 if self.dump_memory:
 200                     hexdata = " ".join("{0:02x}".format(ord(c)) for c in data)
 201                     self.memory['%s (0x%016x)' % (self.name, addr)] = hexdata
 202
 203                 flags &= ~self.RAM_SAVE_FLAG_PAGE
 204             elif flags & self.RAM_SAVE_FLAG_XBZRLE:
 205                 raise Exception("XBZRLE RAM compression is not supported yet")
 206             elif flags & self.RAM_SAVE_FLAG_HOOK:
 207                 raise Exception("RAM hooks don't make sense with files")
 208             if flags & self.RAM_SAVE_FLAG_MULTIFD_FLUSH:
 209                 continue
 210
 211             # End of RAM section
 212             if flags & self.RAM_SAVE_FLAG_EOS:
 213                 break
 214
 215             if flags != 0:
 216                 raise Exception("Unknown RAM flags: %x" % flags)
 217
 218     def __del__(self):
 219         if self.write_memory:
 220             for key in self.files:
 221                 self.files[key].close()
 222
 223
 224 class HTABSection(object):
 225     HASH_PTE_SIZE_64       = 16
 226
 227     def __init__(self, file, version_id, device, section_key):
 228         if version_id != 1:
 229             raise Exception("Unknown HTAB version %d" % version_id)
 230
 231         self.file = file
 232         self.section_key = section_key
 233
 234     def read(self):
 235
 236         header = self.file.read32()
 237
 238         if (header == -1):
 239             # "no HPT" encoding
 240             return
 241
 242         if (header > 0):
 243             # First section, just the hash shift
 244             return
 245
 246         # Read until end marker
 247         while True:
 248             index = self.file.read32()
 249             n_valid = self.file.read16()
 250             n_invalid = self.file.read16()
 251
 252             if index == 0 and n_valid == 0 and n_invalid == 0:
 253                 break
 254
 255             self.file.readvar(n_valid * self.HASH_PTE_SIZE_64)
 256
 257     def getDict(self):
 258         return ""
 259
 260
 261 class S390StorageAttributes(object):
 262     STATTR_FLAG_EOS   = 0x01
 263     STATTR_FLAG_MORE  = 0x02
 264     STATTR_FLAG_ERROR = 0x04
 265     STATTR_FLAG_DONE  = 0x08
 266
 267     def __init__(self, file, version_id, device, section_key):
 268         if version_id != 0:
 269             raise Exception("Unknown storage_attributes version %d" % version_id)
 270
 271         self.file = file
 272         self.section_key = section_key
 273
 274     def read(self):
 275         while True:
 276             addr_flags = self.file.read64()
 277             flags = addr_flags & 0xfff
 278             if (flags & (self.STATTR_FLAG_DONE | self.STATTR_FLAG_EOS)):
 279                 return
 280             if (flags & self.STATTR_FLAG_ERROR):
 281                 raise Exception("Error in migration stream")
 282             count = self.file.read64()
 283             self.file.readvar(count)
 284
 285     def getDict(self):
 286         return ""
 287
 288
 289 class ConfigurationSection(object):
 290     def __init__(self, file, desc):
 291         self.file = file
 292         self.desc = desc
 293         self.caps = []
 294
 295     def parse_capabilities(self, vmsd_caps):
 296         if not vmsd_caps:
 297             return
 298
 299         ncaps = vmsd_caps.data['caps_count'].data
 300         self.caps = vmsd_caps.data['capabilities']
 301
 302         if type(self.caps) != list:
 303             self.caps = [self.caps]
 304
 305         if len(self.caps) != ncaps:
 306             raise Exception("Number of capabilities doesn't match "
 307                             "caps_count field")
 308
 309     def has_capability(self, cap):
 310         return any([str(c) == cap for c in self.caps])
 311
 312     def read(self):
 313         if self.desc:
 314             version_id = self.desc['version']
 315             section = VMSDSection(self.file, version_id, self.desc,
 316                                   'configuration')
 317             section.read()
 318             self.parse_capabilities(
 319                 section.data.get("configuration/capabilities"))
 320         else:
 321             # backward compatibility for older streams that don't have
 322             # the configuration section in the json
 323             name_len = self.file.read32()
 324             name = self.file.readstr(len = name_len)
 325
 326 class VMSDFieldGeneric(object):
 327     def __init__(self, desc, file):
 328         self.file = file
 329         self.desc = desc
 330         self.data = ""
 331
 332     def __repr__(self):
 333         return str(self.__str__())
 334
 335     def __str__(self):
 336         return " ".join("{0:02x}".format(c) for c in self.data)
 337
 338     def getDict(self):
 339         return self.__str__()
 340
 341     def read(self):
 342         size = int(self.desc['size'])
 343         self.data = self.file.readvar(size)
 344         return self.data
 345
 346 class VMSDFieldCap(object):
 347     def __init__(self, desc, file):
 348         self.file = file
 349         self.desc = desc
 350         self.data = ""
 351
 352     def __repr__(self):
 353         return self.data
 354
 355     def __str__(self):
 356         return self.data
 357
 358     def read(self):
 359         len = self.file.read8()
 360         self.data = self.file.readstr(len)
 361
 362
 363 class VMSDFieldInt(VMSDFieldGeneric):
 364     def __init__(self, desc, file):
 365         super(VMSDFieldInt, self).__init__(desc, file)
 366         self.size = int(desc['size'])
 367         self.format = '0x%%0%dx' % (self.size * 2)
 368         self.sdtype = '>i%d' % self.size
 369         self.udtype = '>u%d' % self.size
 370
 371     def __repr__(self):
 372         if self.data < 0:
 373             return ('%s (%d)' % ((self.format % self.udata), self.data))
 374         else:
 375             return self.format % self.data
 376
 377     def __str__(self):
 378         return self.__repr__()
 379
 380     def getDict(self):
 381         return self.__str__()
 382
 383     def read(self):
 384         super(VMSDFieldInt, self).read()
 385         self.sdata = int.from_bytes(self.data, byteorder='big', signed=True)
 386         self.udata = int.from_bytes(self.data, byteorder='big', signed=False)
 387         self.data = self.sdata
 388         return self.data
 389
 390 class VMSDFieldUInt(VMSDFieldInt):
 391     def __init__(self, desc, file):
 392         super(VMSDFieldUInt, self).__init__(desc, file)
 393
 394     def read(self):
 395         super(VMSDFieldUInt, self).read()
 396         self.data = self.udata
 397         return self.data
 398
 399 class VMSDFieldIntLE(VMSDFieldInt):
 400     def __init__(self, desc, file):
 401         super(VMSDFieldIntLE, self).__init__(desc, file)
 402         self.dtype = '<i%d' % self.size
 403
 404 class VMSDFieldBool(VMSDFieldGeneric):
 405     def __init__(self, desc, file):
 406         super(VMSDFieldBool, self).__init__(desc, file)
 407
 408     def __repr__(self):
 409         return self.data.__repr__()
 410
 411     def __str__(self):
 412         return self.data.__str__()
 413
 414     def getDict(self):
 415         return self.data
 416
 417     def read(self):
 418         super(VMSDFieldBool, self).read()
 419         if self.data[0] == 0:
 420             self.data = False
 421         else:
 422             self.data = True
 423         return self.data
 424
 425 class VMSDFieldStruct(VMSDFieldGeneric):
 426     QEMU_VM_SUBSECTION    = 0x05
 427
 428     def __init__(self, desc, file):
 429         super(VMSDFieldStruct, self).__init__(desc, file)
 430         self.data = collections.OrderedDict()
 431
 432         # When we see compressed array elements, unfold them here
 433         new_fields = []
 434         for field in self.desc['struct']['fields']:
 435             if not 'array_len' in field:
 436                 new_fields.append(field)
 437                 continue
 438             array_len = field.pop('array_len')
 439             field['index'] = 0
 440             new_fields.append(field)
 441             for i in range(1, array_len):
 442                 c = field.copy()
 443                 c['index'] = i
 444                 new_fields.append(c)
 445
 446         self.desc['struct']['fields'] = new_fields
 447
 448     def __repr__(self):
 449         return self.data.__repr__()
 450
 451     def __str__(self):
 452         return self.data.__str__()
 453
 454     def read(self):
 455         for field in self.desc['struct']['fields']:
 456             try:
 457                 reader = vmsd_field_readers[field['type']]
 458             except:
 459                 reader = VMSDFieldGeneric
 460
 461             field['data'] = reader(field, self.file)
 462             field['data'].read()
 463
 464             if 'index' in field:
 465                 if field['name'] not in self.data:
 466                     self.data[field['name']] = []
 467                 a = self.data[field['name']]
 468                 if len(a) != int(field['index']):
 469                     raise Exception("internal index of data field unmatched (%d/%d)" % (len(a), int(field['index'])))
 470                 a.append(field['data'])
 471             else:
 472                 self.data[field['name']] = field['data']
 473
 474         if 'subsections' in self.desc['struct']:
 475             for subsection in self.desc['struct']['subsections']:
 476                 if self.file.read8() != self.QEMU_VM_SUBSECTION:
 477                     raise Exception("Subsection %s not found at offset %x" % ( subsection['vmsd_name'], self.file.tell()))
 478                 name = self.file.readstr()
 479                 version_id = self.file.read32()
 480                 self.data[name] = VMSDSection(self.file, version_id, subsection, (name, 0))
 481                 self.data[name].read()
 482
 483     def getDictItem(self, value):
 484        # Strings would fall into the array category, treat
 485        # them specially
 486        if value.__class__ is ''.__class__:
 487            return value
 488
 489        try:
 490            return self.getDictOrderedDict(value)
 491        except:
 492            try:
 493                return self.getDictArray(value)
 494            except:
 495                try:
 496                    return value.getDict()
 497                except:
 498                    return value
 499
 500     def getDictArray(self, array):
 501         r = []
 502         for value in array:
 503            r.append(self.getDictItem(value))
 504         return r
 505
 506     def getDictOrderedDict(self, dict):
 507         r = collections.OrderedDict()
 508         for (key, value) in dict.items():
 509             r[key] = self.getDictItem(value)
 510         return r
 511
 512     def getDict(self):
 513         return self.getDictOrderedDict(self.data)
 514
 515 vmsd_field_readers = {
 516     "bool" : VMSDFieldBool,
 517     "int8" : VMSDFieldInt,
 518     "int16" : VMSDFieldInt,
 519     "int32" : VMSDFieldInt,
 520     "int32 equal" : VMSDFieldInt,
 521     "int32 le" : VMSDFieldIntLE,
 522     "int64" : VMSDFieldInt,
 523     "uint8" : VMSDFieldUInt,
 524     "uint16" : VMSDFieldUInt,
 525     "uint32" : VMSDFieldUInt,
 526     "uint32 equal" : VMSDFieldUInt,
 527     "uint64" : VMSDFieldUInt,
 528     "int64 equal" : VMSDFieldInt,
 529     "uint8 equal" : VMSDFieldInt,
 530     "uint16 equal" : VMSDFieldInt,
 531     "float64" : VMSDFieldGeneric,
 532     "timer" : VMSDFieldGeneric,
 533     "buffer" : VMSDFieldGeneric,
 534     "unused_buffer" : VMSDFieldGeneric,
 535     "bitmap" : VMSDFieldGeneric,
 536     "struct" : VMSDFieldStruct,
 537     "capability": VMSDFieldCap,
 538     "unknown" : VMSDFieldGeneric,
 539 }
 540
 541 class VMSDSection(VMSDFieldStruct):
 542     def __init__(self, file, version_id, device, section_key):
 543         self.file = file
 544         self.data = ""
 545         self.vmsd_name = ""
 546         self.section_key = section_key
 547         desc = device
 548         if 'vmsd_name' in device:
 549             self.vmsd_name = device['vmsd_name']
 550
 551         # A section really is nothing but a FieldStruct :)
 552         super(VMSDSection, self).__init__({ 'struct' : desc }, file)
 553
 554 ###############################################################################
 555
 556 class MigrationDump(object):
 557     QEMU_VM_FILE_MAGIC    = 0x5145564d
 558     QEMU_VM_FILE_VERSION  = 0x00000003
 559     QEMU_VM_EOF           = 0x00
 560     QEMU_VM_SECTION_START = 0x01
 561     QEMU_VM_SECTION_PART  = 0x02
 562     QEMU_VM_SECTION_END   = 0x03
 563     QEMU_VM_SECTION_FULL  = 0x04
 564     QEMU_VM_SUBSECTION    = 0x05
 565     QEMU_VM_VMDESCRIPTION = 0x06
 566     QEMU_VM_CONFIGURATION = 0x07
 567     QEMU_VM_SECTION_FOOTER= 0x7e
 568
 569     def __init__(self, filename):
 570         self.section_classes = {
 571             ( 'ram', 0 ) : [ RamSection, None ],
 572             ( 's390-storage_attributes', 0 ) : [ S390StorageAttributes, None],
 573             ( 'spapr/htab', 0) : ( HTABSection, None )
 574         }
 575         self.filename = filename
 576         self.vmsd_desc = None
 577
 578     def read(self, desc_only = False, dump_memory = False, write_memory = False):
 579         # Read in the whole file
 580         file = MigrationFile(self.filename)
 581
 582         # File magic
 583         data = file.read32()
 584         if data != self.QEMU_VM_FILE_MAGIC:
 585             raise Exception("Invalid file magic %x" % data)
 586
 587         # Version (has to be v3)
 588         data = file.read32()
 589         if data != self.QEMU_VM_FILE_VERSION:
 590             raise Exception("Invalid version number %d" % data)
 591
 592         self.load_vmsd_json(file)
 593
 594         # Read sections
 595         self.sections = collections.OrderedDict()
 596
 597         if desc_only:
 598             return
 599
 600         ramargs = {}
 601         ramargs['page_size'] = self.vmsd_desc['page_size']
 602         ramargs['dump_memory'] = dump_memory
 603         ramargs['write_memory'] = write_memory
 604         ramargs['ignore_shared'] = False
 605         self.section_classes[('ram',0)][1] = ramargs
 606
 607         while True:
 608             section_type = file.read8()
 609             if section_type == self.QEMU_VM_EOF:
 610                 break
 611             elif section_type == self.QEMU_VM_CONFIGURATION:
 612                 config_desc = self.vmsd_desc.get('configuration')
 613                 section = ConfigurationSection(file, config_desc)
 614                 section.read()
 615                 ramargs['ignore_shared'] = section.has_capability('x-ignore-shared')
 616             elif section_type == self.QEMU_VM_SECTION_START or section_type == self.QEMU_VM_SECTION_FULL:
 617                 section_id = file.read32()
 618                 name = file.readstr()
 619                 instance_id = file.read32()
 620                 version_id = file.read32()
 621                 section_key = (name, instance_id)
 622                 classdesc = self.section_classes[section_key]
 623                 section = classdesc[0](file, version_id, classdesc[1], section_key)
 624                 self.sections[section_id] = section
 625                 section.read()
 626             elif section_type == self.QEMU_VM_SECTION_PART or section_type == self.QEMU_VM_SECTION_END:
 627                 section_id = file.read32()
 628                 self.sections[section_id].read()
 629             elif section_type == self.QEMU_VM_SECTION_FOOTER:
 630                 read_section_id = file.read32()
 631                 if read_section_id != section_id:
 632                     raise Exception("Mismatched section footer: %x vs %x" % (read_section_id, section_id))
 633             else:
 634                 raise Exception("Unknown section type: %d" % section_type)
 635         file.close()
 636
 637     def load_vmsd_json(self, file):
 638         vmsd_json = file.read_migration_debug_json()
 639         self.vmsd_desc = json.loads(vmsd_json, object_pairs_hook=collections.OrderedDict)
 640         for device in self.vmsd_desc['devices']:
 641             key = (device['name'], device['instance_id'])
 642             value = ( VMSDSection, device )
 643             self.section_classes[key] = value
 644
 645     def getDict(self):
 646         r = collections.OrderedDict()
 647         for (key, value) in self.sections.items():
 648            key = "%s (%d)" % ( value.section_key[0], key )
 649            r[key] = value.getDict()
 650         return r
 651
 652 ###############################################################################
 653
 654 class JSONEncoder(json.JSONEncoder):
 655     def default(self, o):
 656         if isinstance(o, VMSDFieldGeneric):
 657             return str(o)
 658         return json.JSONEncoder.default(self, o)
 659
 660 parser = argparse.ArgumentParser()
 661 parser.add_argument("-f", "--file", help='migration dump to read from', required=True)
 662 parser.add_argument("-m", "--memory", help='dump RAM contents as well', action='store_true')
 663 parser.add_argument("-d", "--dump", help='what to dump ("state" or "desc")', default='state')
 664 parser.add_argument("-x", "--extract", help='extract contents into individual files', action='store_true')
 665 args = parser.parse_args()
 666
 667 jsonenc = JSONEncoder(indent=4, separators=(',', ': '))
 668
 669 if args.extract:
 670     dump = MigrationDump(args.file)
 671
 672     dump.read(desc_only = True)
 673     print("desc.json")
 674     f = open("desc.json", "w")
 675     f.truncate()
 676     f.write(jsonenc.encode(dump.vmsd_desc))
 677     f.close()
 678
 679     dump.read(write_memory = True)
 680     dict = dump.getDict()
 681     print("state.json")
 682     f = open("state.json", "w")
 683     f.truncate()
 684     f.write(jsonenc.encode(dict))
 685     f.close()
 686 elif args.dump == "state":
 687     dump = MigrationDump(args.file)
 688     dump.read(dump_memory = args.memory)
 689     dict = dump.getDict()
 690     print(jsonenc.encode(dict))
 691 elif args.dump == "desc":
 692     dump = MigrationDump(args.file)
 693     dump.read(desc_only = True)
 694     print(jsonenc.encode(dump.vmsd_desc))
 695 else:
 696     raise Exception("Please specify either -x, -d state or -d desc")