--- /dev/null
+#!/usr/bin/env python
+#
+# Tool to manipulate QED image files
+#
+# Copyright (C) 2010 IBM, Corp.
+#
+# Authors:
+# Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or later.
+# See the COPYING file in the top-level directory.
+
+import sys
+import struct
+import random
+import optparse
+
+# This can be used as a module
+__all__ = ['QED_F_NEED_CHECK', 'QED']
+
+QED_F_NEED_CHECK = 0x02
+
+header_fmt = '<IIIIQQQQQII'
+header_size = struct.calcsize(header_fmt)
+field_names = ['magic', 'cluster_size', 'table_size',
+ 'header_size', 'features', 'compat_features',
+ 'autoclear_features', 'l1_table_offset', 'image_size',
+ 'backing_filename_offset', 'backing_filename_size']
+table_elem_fmt = '<Q'
+table_elem_size = struct.calcsize(table_elem_fmt)
+
+def err(msg):
+ sys.stderr.write(msg + '\n')
+ sys.exit(1)
+
+def unpack_header(s):
+ fields = struct.unpack(header_fmt, s)
+ return dict((field_names[idx], val) for idx, val in enumerate(fields))
+
+def pack_header(header):
+ fields = tuple(header[x] for x in field_names)
+ return struct.pack(header_fmt, *fields)
+
+def unpack_table_elem(s):
+ return struct.unpack(table_elem_fmt, s)[0]
+
+def pack_table_elem(elem):
+ return struct.pack(table_elem_fmt, elem)
+
+class QED(object):
+ def __init__(self, f):
+ self.f = f
+
+ self.f.seek(0, 2)
+ self.filesize = f.tell()
+
+ self.load_header()
+ self.load_l1_table()
+
+ def raw_pread(self, offset, size):
+ self.f.seek(offset)
+ return self.f.read(size)
+
+ def raw_pwrite(self, offset, data):
+ self.f.seek(offset)
+ return self.f.write(data)
+
+ def load_header(self):
+ self.header = unpack_header(self.raw_pread(0, header_size))
+
+ def store_header(self):
+ self.raw_pwrite(0, pack_header(self.header))
+
+ def read_table(self, offset):
+ size = self.header['table_size'] * self.header['cluster_size']
+ s = self.raw_pread(offset, size)
+ table = [unpack_table_elem(s[i:i + table_elem_size]) for i in xrange(0, size, table_elem_size)]
+ return table
+
+ def load_l1_table(self):
+ self.l1_table = self.read_table(self.header['l1_table_offset'])
+ self.table_nelems = self.header['table_size'] * self.header['cluster_size'] / table_elem_size
+
+ def write_table(self, offset, table):
+ s = ''.join(pack_table_elem(x) for x in table)
+ self.raw_pwrite(offset, s)
+
+def random_table_item(table):
+ vals = [(index, offset) for index, offset in enumerate(table) if offset != 0]
+ if not vals:
+ err('cannot pick random item because table is empty')
+ return random.choice(vals)
+
+def corrupt_table_duplicate(table):
+ '''Corrupt a table by introducing a duplicate offset'''
+ victim_idx, victim_val = random_table_item(table)
+ unique_vals = set(table)
+ if len(unique_vals) == 1:
+ err('no duplication corruption possible in table')
+ dup_val = random.choice(list(unique_vals.difference([victim_val])))
+ table[victim_idx] = dup_val
+
+def corrupt_table_invalidate(qed, table):
+ '''Corrupt a table by introducing an invalid offset'''
+ index, _ = random_table_item(table)
+ table[index] = qed.filesize + random.randint(0, 100 * 1024 * 1024 * 1024 * 1024)
+
+def cmd_show(qed, *args):
+ '''show [header|l1|l2 <offset>]- Show header or l1/l2 tables'''
+ if not args or args[0] == 'header':
+ print qed.header
+ elif args[0] == 'l1':
+ print qed.l1_table
+ elif len(args) == 2 and args[0] == 'l2':
+ offset = int(args[1])
+ print qed.read_table(offset)
+ else:
+ err('unrecognized sub-command')
+
+def cmd_duplicate(qed, table_level):
+ '''duplicate l1|l2 - Duplicate a random table element'''
+ if table_level == 'l1':
+ offset = qed.header['l1_table_offset']
+ table = qed.l1_table
+ elif table_level == 'l2':
+ _, offset = random_table_item(qed.l1_table)
+ table = qed.read_table(offset)
+ else:
+ err('unrecognized sub-command')
+ corrupt_table_duplicate(table)
+ qed.write_table(offset, table)
+
+def cmd_invalidate(qed, table_level):
+ '''invalidate l1|l2 - Plant an invalid table element at random'''
+ if table_level == 'l1':
+ offset = qed.header['l1_table_offset']
+ table = qed.l1_table
+ elif table_level == 'l2':
+ _, offset = random_table_item(qed.l1_table)
+ table = qed.read_table(offset)
+ else:
+ err('unrecognized sub-command')
+ corrupt_table_invalidate(qed, table)
+ qed.write_table(offset, table)
+
+def cmd_need_check(qed, *args):
+ '''need-check [on|off] - Test, set, or clear the QED_F_NEED_CHECK header bit'''
+ if not args:
+ print bool(qed.header['features'] & QED_F_NEED_CHECK)
+ return
+
+ if args[0] == 'on':
+ qed.header['features'] |= QED_F_NEED_CHECK
+ elif args[0] == 'off':
+ qed.header['features'] &= ~QED_F_NEED_CHECK
+ else:
+ err('unrecognized sub-command')
+ qed.store_header()
+
+def cmd_zero_cluster(qed, pos, *args):
+ '''zero-cluster <pos> [<n>] - Zero data clusters'''
+ pos, n = int(pos), 1
+ if args:
+ if len(args) != 1:
+ err('expected one argument')
+ n = int(args[0])
+
+ for i in xrange(n):
+ l1_index = pos / qed.header['cluster_size'] / len(qed.l1_table)
+ if qed.l1_table[l1_index] == 0:
+ err('no l2 table allocated')
+
+ l2_offset = qed.l1_table[l1_index]
+ l2_table = qed.read_table(l2_offset)
+
+ l2_index = (pos / qed.header['cluster_size']) % len(qed.l1_table)
+ l2_table[l2_index] = 1 # zero the data cluster
+ qed.write_table(l2_offset, l2_table)
+ pos += qed.header['cluster_size']
+
+def cmd_copy_metadata(qed, outfile):
+ '''copy-metadata <outfile> - Copy metadata only (for scrubbing corrupted images)'''
+ out = open(outfile, 'wb')
+
+ # Match file size
+ out.seek(qed.filesize - 1)
+ out.write('\0')
+
+ # Copy header clusters
+ out.seek(0)
+ header_size_bytes = qed.header['header_size'] * qed.header['cluster_size']
+ out.write(qed.raw_pread(0, header_size_bytes))
+
+ # Copy L1 table
+ out.seek(qed.header['l1_table_offset'])
+ s = ''.join(pack_table_elem(x) for x in qed.l1_table)
+ out.write(s)
+
+ # Copy L2 tables
+ for l2_offset in qed.l1_table:
+ if l2_offset == 0:
+ continue
+ l2_table = qed.read_table(l2_offset)
+ out.seek(l2_offset)
+ s = ''.join(pack_table_elem(x) for x in l2_table)
+ out.write(s)
+
+ out.close()
+
+def usage():
+ print 'Usage: %s <file> <cmd> [<arg>, ...]' % sys.argv[0]
+ print
+ print 'Supported commands:'
+ for cmd in sorted(x for x in globals() if x.startswith('cmd_')):
+ print globals()[cmd].__doc__
+ sys.exit(1)
+
+def main():
+ if len(sys.argv) < 3:
+ usage()
+ filename, cmd = sys.argv[1:3]
+
+ cmd = 'cmd_' + cmd.replace('-', '_')
+ if cmd not in globals():
+ usage()
+
+ qed = QED(open(filename, 'r+b'))
+ try:
+ globals()[cmd](qed, *sys.argv[3:])
+ except TypeError, e:
+ sys.stderr.write(globals()[cmd].__doc__ + '\n')
+ sys.exit(1)
+
+if __name__ == '__main__':
+ main()
Code Review / kvmfornfv.git / blobdiff