tests/qemu-iotests/qcow2.py

   1 #!/usr/bin/env python3
   2 #
   3 # Manipulations with qcow2 image
   4 #
   5 # Copyright (C) 2012 Red Hat, Inc.
   6 #
   7 # This program is free software; you can redistribute it and/or modify
   8 # it under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation; either version 2 of the License, or
  10 # (at your option) any later version.
  11 #
  12 # This program 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
  15 # GNU General Public License for more details.
  16 #
  17 # You should have received a copy of the GNU General Public License
  18 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 #
  20
  21 import sys
  22
  23 from qcow2_format import (
  24     QcowHeader,
  25     QcowHeaderExtension
  26 )
  27
  28
  29 def cmd_dump_header(fd):
  30     h = QcowHeader(fd)
  31     h.dump()
  32     print()
  33     h.dump_extensions()
  34
  35
  36 def cmd_dump_header_exts(fd):
  37     h = QcowHeader(fd)
  38     h.dump_extensions()
  39
  40
  41 def cmd_set_header(fd, name, value):
  42     try:
  43         value = int(value, 0)
  44     except ValueError:
  45         print("'%s' is not a valid number" % value)
  46         sys.exit(1)
  47
  48     fields = (field[2] for field in QcowHeader.fields)
  49     if name not in fields:
  50         print("'%s' is not a known header field" % name)
  51         sys.exit(1)
  52
  53     h = QcowHeader(fd)
  54     h.__dict__[name] = value
  55     h.update(fd)
  56
  57
  58 def cmd_add_header_ext(fd, magic, data):
  59     try:
  60         magic = int(magic, 0)
  61     except ValueError:
  62         print("'%s' is not a valid magic number" % magic)
  63         sys.exit(1)
  64
  65     h = QcowHeader(fd)
  66     h.extensions.append(QcowHeaderExtension.create(magic,
  67                                                    data.encode('ascii')))
  68     h.update(fd)
  69
  70
  71 def cmd_add_header_ext_stdio(fd, magic):
  72     data = sys.stdin.read()
  73     cmd_add_header_ext(fd, magic, data)
  74
  75
  76 def cmd_del_header_ext(fd, magic):
  77     try:
  78         magic = int(magic, 0)
  79     except ValueError:
  80         print("'%s' is not a valid magic number" % magic)
  81         sys.exit(1)
  82
  83     h = QcowHeader(fd)
  84     found = False
  85
  86     for ex in h.extensions:
  87         if ex.magic == magic:
  88             found = True
  89             h.extensions.remove(ex)
  90
  91     if not found:
  92         print("No such header extension")
  93         return
  94
  95     h.update(fd)
  96
  97
  98 def cmd_set_feature_bit(fd, group, bit):
  99     try:
 100         bit = int(bit, 0)
 101         if bit < 0 or bit >= 64:
 102             raise ValueError
 103     except ValueError:
 104         print("'%s' is not a valid bit number in range [0, 64)" % bit)
 105         sys.exit(1)
 106
 107     h = QcowHeader(fd)
 108     if group == 'incompatible':
 109         h.incompatible_features |= 1 << bit
 110     elif group == 'compatible':
 111         h.compatible_features |= 1 << bit
 112     elif group == 'autoclear':
 113         h.autoclear_features |= 1 << bit
 114     else:
 115         print("'%s' is not a valid group, try "
 116               "'incompatible', 'compatible', or 'autoclear'" % group)
 117         sys.exit(1)
 118
 119     h.update(fd)
 120
 121
 122 cmds = [
 123     ['dump-header', cmd_dump_header, 0,
 124      'Dump image header and header extensions'],
 125     ['dump-header-exts', cmd_dump_header_exts, 0,
 126      'Dump image header extensions'],
 127     ['set-header', cmd_set_header, 2, 'Set a field in the header'],
 128     ['add-header-ext', cmd_add_header_ext, 2, 'Add a header extension'],
 129     ['add-header-ext-stdio', cmd_add_header_ext_stdio, 1,
 130      'Add a header extension, data from stdin'],
 131     ['del-header-ext', cmd_del_header_ext, 1, 'Delete a header extension'],
 132     ['set-feature-bit', cmd_set_feature_bit, 2, 'Set a feature bit'],
 133 ]
 134
 135
 136 def main(filename, cmd, args):
 137     fd = open(filename, "r+b")
 138     try:
 139         for name, handler, num_args, desc in cmds:
 140             if name != cmd:
 141                 continue
 142             elif len(args) != num_args:
 143                 usage()
 144                 return
 145             else:
 146                 handler(fd, *args)
 147                 return
 148         print("Unknown command '%s'" % cmd)
 149     finally:
 150         fd.close()
 151
 152
 153 def usage():
 154     print("Usage: %s <file> <cmd> [<arg>, ...]" % sys.argv[0])
 155     print("")
 156     print("Supported commands:")
 157     for name, handler, num_args, desc in cmds:
 158         print("    %-20s - %s" % (name, desc))
 159
 160
 161 if __name__ == '__main__':
 162     if len(sys.argv) < 3:
 163         usage()
 164         sys.exit(1)
 165
 166     main(sys.argv[1], sys.argv[2], sys.argv[3:])