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Diffstat (limited to 'scripts/lib/wic/plugins/source/empty.py')
-rw-r--r-- | scripts/lib/wic/plugins/source/empty.py | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/scripts/lib/wic/plugins/source/empty.py b/scripts/lib/wic/plugins/source/empty.py new file mode 100644 index 0000000000..4178912377 --- /dev/null +++ b/scripts/lib/wic/plugins/source/empty.py @@ -0,0 +1,89 @@ +# +# Copyright OpenEmbedded Contributors +# +# SPDX-License-Identifier: MIT +# + +# The empty wic plugin is used to create unformatted empty partitions for wic +# images. +# 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') + +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' + + @classmethod + def do_prepare_partition(cls, part, source_params, cr, cr_workdir, + oe_builddir, bootimg_dir, kernel_dir, + rootfs_dir, native_sysroot): + """ + Called to do the actual content population for a partition i.e. it + 'prepares' the partition to be incorporated into the image. + """ + 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 |