Read and dump entries from the bitmap directory of QCOW2 image with the
script qcow2.py.
Header extension: Bitmaps
...
Bitmap name bitmap-1
flag auto
bitmap_table_offset 0xf0000
bitmap_table_size 8
flag_bits 2
type 1
granularity_bits 16
name_size 8
extra_data_size 0
Suggested-by: Kevin Wolf <kw...@redhat.com>
Signed-off-by: Andrey Shinkevich <andrey.shinkev...@virtuozzo.com>
---
tests/qemu-iotests/qcow2.py | 104 +++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 103 insertions(+), 1 deletion(-)
diff --git a/tests/qemu-iotests/qcow2.py b/tests/qemu-iotests/qcow2.py
index 8286115..e4453f6 100755
--- a/tests/qemu-iotests/qcow2.py
+++ b/tests/qemu-iotests/qcow2.py
@@ -5,6 +5,88 @@ import struct
import string
+class Qcow2BitmapDirEntry:
+
+ name = ''
+
+ uint8_t = 'B'
+ uint16_t = 'H'
+ uint32_t = 'I'
+ uint64_t = 'Q'
+
+ fields = [
+ [uint64_t, '%#x', 'bitmap_table_offset'],
+ [uint32_t, '%d', 'bitmap_table_size'],
+ [uint32_t, '%d', 'flag_bits'],
+ [uint8_t, '%d', 'type'],
+ [uint8_t, '%d', 'granularity_bits'],
+ [uint16_t, '%d', 'name_size'],
+ [uint32_t, '%d', 'extra_data_size']
+ ]
+
+ fmt = '>' + ''.join(field[0] for field in fields)
+
+ def __init__(self, data):
+
+ entry = struct.unpack(Qcow2BitmapDirEntry.fmt, data)
+ self.__dict__ = dict((field[2], entry[i])
+ for i, field in enumerate(
+ Qcow2BitmapDirEntry.fields))
+
+ self.bitmap_table_size = self.bitmap_table_size \
+ * struct.calcsize(self.uint64_t)
+
+ self.bitmap_flags = []
+ BME_FLAG_IN_USE = 1
+ BME_FLAG_AUTO = 1 << 1
+ if (self.flag_bits & BME_FLAG_IN_USE) != 0:
+ self.bitmap_flags.append("in-use")
+ if (self.flag_bits & BME_FLAG_AUTO) != 0:
+ self.bitmap_flags.append("auto")
+
+ def bitmap_dir_entry_raw_size(self):
+ return struct.calcsize(self.fmt) + self.name_size + \
+ self.extra_data_size
+
+ def dump_bitmap_dir_entry(self):
+ print("%-25s" % 'Bitmap name', self.name)
+
+ for fl in self.bitmap_flags:
+ print("%-25s" % 'flag', fl)
+
+ for f in Qcow2BitmapDirEntry.fields:
+ value = self.__dict__[f[2]]
+ value_str = f[1] % value
+ print("%-25s" % f[2], value_str)
+
+
+class Qcow2BitmapDirectory:
+
+ def __init__(self, bm_header_ext):
+ self.nb_bitmaps = bm_header_ext.nb_bitmaps
+ self.bitmap_directory_offset = bm_header_ext.bitmap_directory_offset
+ self.bitmap_directory_size = bm_header_ext.bitmap_directory_size
+
+ def read_bitmap_directory(self, fd):
+ self.bitmaps = []
+ fd.seek(self.bitmap_directory_offset)
+ buf_size = struct.calcsize(Qcow2BitmapDirEntry.fmt)
+
+ for n in range(self.nb_bitmaps):
+ buf = fd.read(buf_size)
+ dir_entry = Qcow2BitmapDirEntry(buf)
+ fd.seek(dir_entry.extra_data_size, 1)
+ bitmap_name = fd.read(dir_entry.name_size)
+ dir_entry.name = bitmap_name.decode('ascii')
+ self.bitmaps.append(dir_entry)
+ entry_raw_size = dir_entry.bitmap_dir_entry_raw_size()
+ shift = ((entry_raw_size + 7) & ~7) - entry_raw_size
+ fd.seek(shift, 1)
+
+ def get_bitmaps(self):
+ return self.bitmaps
+
+
class Qcow2BitmapExt:
uint32_t = 'I'
@@ -33,8 +115,21 @@ class Qcow2BitmapExt:
print("%-25s" % f[2], value_str)
print("")
+ def read_bitmap_directory(self, fd):
+ bm_directory = Qcow2BitmapDirectory(self)
+ bm_directory.read_bitmap_directory(fd)
+ self.bitmaps = bm_directory.get_bitmaps()
+
+ def load(self, fd):
+ self.read_bitmap_directory(fd)
+
+ def dump_bitmap_directory(self):
+ for bm in self.bitmaps:
+ bm.dump_bitmap_dir_entry()
+
def dump_ext(self):
self.dump_bitmap_ext()
+ self.dump_bitmap_directory()
class QcowHeaderExtension:
@@ -79,6 +174,10 @@ class QcowHeaderExtension:
self.QCOW2_EXT_MAGIC_DATA_FILE: 'Data file',
}.get(magic, 'Unknown')
+ def load(self, fd):
+ if self.obj is not None:
+ self.obj.load(fd)
+
class QcowHeader:
@@ -157,7 +256,10 @@ class QcowHeader:
else:
padded = (length + 7) & ~7
data = fd.read(padded)
- self.extensions.append(QcowHeaderExtension(magic, length,
data))
+ self.extensions.append(QcowHeaderExtension(magic, length,
+ data))
+ for ex in self.extensions:
+ ex.load(fd)
def update_extensions(self, fd):
--
1.8.3.1
