diff options
Diffstat (limited to 'scripts/lib/wic/filemap.py')
| -rw-r--r-- | scripts/lib/wic/filemap.py | 117 |
1 files changed, 54 insertions, 63 deletions
diff --git a/scripts/lib/wic/filemap.py b/scripts/lib/wic/filemap.py index 77e32b9add..85b39d5d74 100644 --- a/scripts/lib/wic/filemap.py +++ b/scripts/lib/wic/filemap.py @@ -1,13 +1,8 @@ +# # Copyright (c) 2012 Intel, Inc. # -# This program is free software; you can redistribute it and/or modify -# it under the terms of the GNU General Public License, version 2, -# as published by the Free Software Foundation. +# SPDX-License-Identifier: GPL-2.0-only # -# This program is distributed in the hope that it will be useful, but -# WITHOUT ANY WARRANTY; without even the implied warranty of -# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU -# General Public License for more details. """ This module implements python implements a way to get file block. Two methods @@ -22,6 +17,7 @@ and returns an instance of the class. # * Too many instance attributes (R0902) # pylint: disable=R0902 +import errno import os import struct import array @@ -36,8 +32,28 @@ def get_block_size(file_obj): """ # Get the block size of the host file-system for the image file by calling # the FIGETBSZ ioctl (number 2). - binary_data = fcntl.ioctl(file_obj, 2, struct.pack('I', 0)) - return struct.unpack('I', binary_data)[0] + try: + binary_data = fcntl.ioctl(file_obj, 2, struct.pack('I', 0)) + bsize = struct.unpack('I', binary_data)[0] + except OSError: + bsize = None + + # If ioctl causes OSError or give bsize to zero failback to os.fstat + if not bsize: + import os + stat = os.fstat(file_obj.fileno()) + if hasattr(stat, 'st_blksize'): + bsize = stat.st_blksize + else: + raise IOError("Unable to determine block size") + + # The logic in this script only supports a maximum of a 4KB + # block size + max_block_size = 4 * 1024 + if bsize > max_block_size: + bsize = max_block_size + + return bsize class ErrorNotSupp(Exception): """ @@ -133,15 +149,6 @@ class _FilemapBase(object): raise Error("the method is not implemented") - def block_is_unmapped(self, block): # pylint: disable=W0613,R0201 - """ - This method has has to be implemented by child classes. It returns - 'True' if block number 'block' of the image file is not mapped (hole) - and 'False' otherwise. - """ - - raise Error("the method is not implemented") - def get_mapped_ranges(self, start, count): # pylint: disable=W0613,R0201 """ This method has has to be implemented by child classes. This is a @@ -155,15 +162,6 @@ class _FilemapBase(object): raise Error("the method is not implemented") - def get_unmapped_ranges(self, start, count): # pylint: disable=W0613,R0201 - """ - This method has has to be implemented by child classes. Just like - 'get_mapped_ranges()', but yields unmapped block ranges instead - (holes). - """ - - raise Error("the method is not implemented") - # The 'SEEK_HOLE' and 'SEEK_DATA' options of the file seek system call _SEEK_DATA = 3 @@ -181,9 +179,9 @@ def _lseek(file_obj, offset, whence): except OSError as err: # The 'lseek' system call returns the ENXIO if there is no data or # hole starting from the specified offset. - if err.errno == os.errno.ENXIO: + if err.errno == errno.ENXIO: return -1 - elif err.errno == os.errno.EINVAL: + elif err.errno == errno.EINVAL: raise ErrorNotSupp("the kernel or file-system does not support " "\"SEEK_HOLE\" and \"SEEK_DATA\"") else: @@ -256,15 +254,10 @@ class FilemapSeek(_FilemapBase): % (block, result)) return result - def block_is_unmapped(self, block): - """Refer the '_FilemapBase' class for the documentation.""" - return not self.block_is_mapped(block) - def _get_ranges(self, start, count, whence1, whence2): """ - This function implements 'get_mapped_ranges()' and - 'get_unmapped_ranges()' depending on what is passed in the 'whence1' - and 'whence2' arguments. + This function implements 'get_mapped_ranges()' depending + on what is passed in the 'whence1' and 'whence2' arguments. """ assert whence1 != whence2 @@ -294,12 +287,6 @@ class FilemapSeek(_FilemapBase): % (start, count, start + count - 1)) return self._get_ranges(start, count, _SEEK_DATA, _SEEK_HOLE) - def get_unmapped_ranges(self, start, count): - """Refer the '_FilemapBase' class for the documentation.""" - self._log.debug("FilemapSeek: get_unmapped_ranges(%d, %d(%d))" - % (start, count, start + count - 1)) - return self._get_ranges(start, count, _SEEK_HOLE, _SEEK_DATA) - # Below goes the FIEMAP ioctl implementation, which is not very readable # because it deals with the rather complex FIEMAP ioctl. To understand the @@ -386,12 +373,12 @@ class FilemapFiemap(_FilemapBase): except IOError as err: # Note, the FIEMAP ioctl is supported by the Linux kernel starting # from version 2.6.28 (year 2008). - if err.errno == os.errno.EOPNOTSUPP: + if err.errno == errno.EOPNOTSUPP: errstr = "FilemapFiemap: the FIEMAP ioctl is not supported " \ "by the file-system" self._log.debug(errstr) raise ErrorNotSupp(errstr) - if err.errno == os.errno.ENOTTY: + if err.errno == errno.ENOTTY: errstr = "FilemapFiemap: the FIEMAP ioctl is not supported " \ "by the kernel" self._log.debug(errstr) @@ -413,10 +400,6 @@ class FilemapFiemap(_FilemapBase): % (block, result)) return result - def block_is_unmapped(self, block): - """Refer the '_FilemapBase' class for the documentation.""" - return not self.block_is_mapped(block) - def _unpack_fiemap_extent(self, index): """ Unpack a 'struct fiemap_extent' structure object number 'index' from @@ -493,23 +476,28 @@ class FilemapFiemap(_FilemapBase): % (first_prev, last_prev)) yield (first_prev, last_prev) - def get_unmapped_ranges(self, start, count): +class FilemapNobmap(_FilemapBase): + """ + This class is used when both the 'SEEK_DATA/HOLE' and FIEMAP are not + supported by the filesystem or kernel. + """ + + def __init__(self, image, log=None): """Refer the '_FilemapBase' class for the documentation.""" - self._log.debug("FilemapFiemap: get_unmapped_ranges(%d, %d(%d))" - % (start, count, start + count - 1)) - hole_first = start - for first, last in self._do_get_mapped_ranges(start, count): - if first > hole_first: - self._log.debug("FilemapFiemap: yielding range (%d, %d)" - % (hole_first, first - 1)) - yield (hole_first, first - 1) - hole_first = last + 1 + # Call the base class constructor first + _FilemapBase.__init__(self, image, log) + self._log.debug("FilemapNobmap: initializing") - if hole_first < start + count: - self._log.debug("FilemapFiemap: yielding range (%d, %d)" - % (hole_first, start + count - 1)) - yield (hole_first, start + count - 1) + def block_is_mapped(self, block): + """Refer the '_FilemapBase' class for the documentation.""" + return True + + def get_mapped_ranges(self, start, count): + """Refer the '_FilemapBase' class for the documentation.""" + self._log.debug("FilemapNobmap: get_mapped_ranges(%d, %d(%d))" + % (start, count, start + count - 1)) + yield (start, start + count -1) def filemap(image, log=None): """ @@ -524,7 +512,10 @@ def filemap(image, log=None): try: return FilemapFiemap(image, log) except ErrorNotSupp: - return FilemapSeek(image, log) + try: + return FilemapSeek(image, log) + except ErrorNotSupp: + return FilemapNobmap(image, log) def sparse_copy(src_fname, dst_fname, skip=0, seek=0, length=0, api=None): |