From 991a02ca7f886fb7935d8d64e50ffe72af281e7c Mon Sep 17 00:00:00 2001 From: Andrey Shinkevich Date: Thu, 6 Aug 2020 22:35:49 +0300 Subject: qcow2_format.py: change Qcow2BitmapExt initialization method There are two ways to initialize a class derived from Qcow2Struct: 1. Pass a block of binary data to the constructor. 2. Pass the file descriptor to allow reading the file from constructor. Let's change the Qcow2BitmapExt initialization method from 1 to 2 to support a scattered reading in the initialization chain. The implementation comes with the patch that follows. Suggested-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Andrey Shinkevich Reviewed-by: Vladimir Sementsov-Ogievskiy Message-Id: <1596742557-320265-4-git-send-email-andrey.shinkevich@virtuozzo.com> Signed-off-by: Eric Blake --- tests/qemu-iotests/qcow2_format.py | 36 ++++++++++++++++++++++-------------- 1 file changed, 22 insertions(+), 14 deletions(-) diff --git a/tests/qemu-iotests/qcow2_format.py b/tests/qemu-iotests/qcow2_format.py index 2f3681bb5f..d4a9974537 100644 --- a/tests/qemu-iotests/qcow2_format.py +++ b/tests/qemu-iotests/qcow2_format.py @@ -113,6 +113,11 @@ class Qcow2BitmapExt(Qcow2Struct): ('u64', '{:#x}', 'bitmap_directory_offset') ) + def __init__(self, fd): + super().__init__(fd=fd) + tail = struct.calcsize(self.fmt) % 8 + if tail: + fd.seek(8 - tail, 1) QCOW2_EXT_MAGIC_BITMAPS = 0x23852875 @@ -161,21 +166,24 @@ class QcowHeaderExtension(Qcow2Struct): else: assert all(v is None for v in (magic, length, data)) super().__init__(fd=fd) - padded = (self.length + 7) & ~7 - self.data = fd.read(padded) - assert self.data is not None - - data_str = self.data[:self.length] - if all(c in string.printable.encode('ascii') for c in data_str): - data_str = f"'{ data_str.decode('ascii') }'" - else: - data_str = '' - self.data_str = data_str + if self.magic == QCOW2_EXT_MAGIC_BITMAPS: + self.obj = Qcow2BitmapExt(fd=fd) + self.data = None + else: + padded = (self.length + 7) & ~7 + self.data = fd.read(padded) + assert self.data is not None + self.obj = None + + if self.data is not None: + data_str = self.data[:self.length] + if all(c in string.printable.encode( + 'ascii') for c in data_str): + data_str = f"'{ data_str.decode('ascii') }'" + else: + data_str = '' + self.data_str = data_str - if self.magic == QCOW2_EXT_MAGIC_BITMAPS: - self.obj = Qcow2BitmapExt(data=self.data) - else: - self.obj = None def dump(self): super().dump() -- cgit v1.2.3