diff options
Diffstat (limited to 'scripts/lib/wic/plugins/source/empty.py')
| -rw-r--r-- | scripts/lib/wic/plugins/source/empty.py | 59 |
1 files changed, 58 insertions, 1 deletions
diff --git a/scripts/lib/wic/plugins/source/empty.py b/scripts/lib/wic/plugins/source/empty.py index 041617d648..4178912377 100644 --- a/scripts/lib/wic/plugins/source/empty.py +++ b/scripts/lib/wic/plugins/source/empty.py @@ -1,4 +1,6 @@ # +# Copyright OpenEmbedded Contributors +# # SPDX-License-Identifier: MIT # @@ -7,9 +9,19 @@ # To use it you must pass "empty" as argument for the "--source" parameter in # the wks file. For example: # part foo --source empty --ondisk sda --size="1024" --align 1024 +# +# The plugin supports writing zeros to the start of the +# partition. This is useful to overwrite old content like +# filesystem signatures which may be re-recognized otherwise. +# This feature can be enabled with +# '--sourceparams="[fill|size=<N>[S|s|K|k|M|G]][,][bs=<N>[S|s|K|k|M|G]]"' +# Conflicting or missing options throw errors. import logging +import os +from wic import WicError +from wic.ksparser import sizetype from wic.pluginbase import SourcePlugin logger = logging.getLogger('wic') @@ -17,6 +29,16 @@ logger = logging.getLogger('wic') class EmptyPartitionPlugin(SourcePlugin): """ Populate unformatted empty partition. + + The following sourceparams are supported: + - fill + Fill the entire partition with zeros. Requires '--fixed-size' option + to be set. + - size=<N>[S|s|K|k|M|G] + Set the first N bytes of the partition to zero. Default unit is 'K'. + - bs=<N>[S|s|K|k|M|G] + Write at most N bytes at a time during source file creation. + Defaults to '1M'. Default unit is 'K'. """ name = 'empty' @@ -29,4 +51,39 @@ class EmptyPartitionPlugin(SourcePlugin): Called to do the actual content population for a partition i.e. it 'prepares' the partition to be incorporated into the image. """ - return + get_byte_count = sizetype('K', True) + size = 0 + + if 'fill' in source_params and 'size' in source_params: + raise WicError("Conflicting source parameters 'fill' and 'size' specified, exiting.") + + # Set the size of the zeros to be written to the partition + if 'fill' in source_params: + if part.fixed_size == 0: + raise WicError("Source parameter 'fill' only works with the '--fixed-size' option, exiting.") + size = get_byte_count(part.fixed_size) + elif 'size' in source_params: + size = get_byte_count(source_params['size']) + + if size == 0: + # Nothing to do, create empty partition + return + + if 'bs' in source_params: + bs = get_byte_count(source_params['bs']) + else: + bs = get_byte_count('1M') + + # Create a binary file of the requested size filled with zeros + source_file = os.path.join(cr_workdir, 'empty-plugin-zeros%s.bin' % part.lineno) + if not os.path.exists(os.path.dirname(source_file)): + os.makedirs(os.path.dirname(source_file)) + + quotient, remainder = divmod(size, bs) + with open(source_file, 'wb') as file: + for _ in range(quotient): + file.write(bytearray(bs)) + file.write(bytearray(remainder)) + + part.size = (size + 1024 - 1) // 1024 # size in KB rounded up + part.source_file = source_file |