| 1 | #!/usr/bin/env python
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| 2 | #
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| 3 | # SPDX-FileCopyrightText: 2008 Martin Decky
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| 4 | # SPDX-FileCopyrightText: 2011 Martin Sucha
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| 5 | #
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| 6 | # SPDX-License-Identifier: BSD-3-Clause
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| 7 | #
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| 8 |
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| 9 | """
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| 10 | Utilities for filesystem image creators
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| 11 | """
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| 12 |
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| 13 | import os
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| 14 | import stat
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| 15 |
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| 16 | exclude_names = set(['.svn', '.bzr', '.git'])
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| 17 |
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| 18 | def align_up(size, alignment):
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| 19 | "Return size aligned up to alignment"
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| 20 |
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| 21 | if (size % alignment == 0):
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| 22 | return size
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| 23 |
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| 24 | return ((size // alignment) + 1) * alignment
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| 25 |
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| 26 | def count_up(size, alignment):
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| 27 | "Return units necessary to fit the size"
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| 28 |
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| 29 | if (size % alignment == 0):
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| 30 | return (size // alignment)
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| 31 |
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| 32 | return ((size // alignment) + 1)
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| 33 |
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| 34 | def num_of_trailing_bin_zeros(num):
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| 35 | "Return number of trailing zeros in binary representation"
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| 36 |
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| 37 | i = 0
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| 38 | if (num == 0): raise ValueError()
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| 39 | while num & 1 == 0:
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| 40 | i += 1
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| 41 | num = num >> 1
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| 42 | return i
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| 43 |
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| 44 | def get_bit(number, n):
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| 45 | "Return True if n-th least-significant bit is set in the given number"
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| 46 |
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| 47 | return bool((number >> n) & 1)
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| 48 |
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| 49 | def set_bit(number, n):
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| 50 | "Return the number with n-th least-significant bit set"
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| 51 |
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| 52 | return number | (1 << n)
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| 53 |
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| 54 | class ItemToPack:
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| 55 | "Stores information about one directory item to be added to the image"
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| 56 |
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| 57 | def __init__(self, parent, name):
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| 58 | self.parent = parent
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| 59 | self.name = name
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| 60 | self.path = os.path.join(parent, name)
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| 61 | self.stat = os.stat(self.path)
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| 62 | self.is_dir = stat.S_ISDIR(self.stat.st_mode)
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| 63 | self.is_file = stat.S_ISREG(self.stat.st_mode)
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| 64 | self.size = self.stat.st_size
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| 65 |
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| 66 | def listdir_items(path):
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| 67 | "Return a list of items to be packed inside a fs image"
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| 68 |
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| 69 | for name in os.listdir(path):
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| 70 | if name in exclude_names:
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| 71 | continue
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| 72 |
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| 73 | item = ItemToPack(path, name)
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| 74 |
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| 75 | if not (item.is_dir or item.is_file):
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| 76 | continue
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| 77 |
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| 78 | yield item
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| 79 |
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| 80 | def chunks(item, chunk_size):
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| 81 | "Iterate contents of a file in chunks of a given size"
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| 82 |
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| 83 | inf = open(item.path, 'rb')
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| 84 | rd = 0
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| 85 |
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| 86 | while (rd < item.size):
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| 87 | data = bytes(inf.read(chunk_size))
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| 88 | yield data
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| 89 | rd += len(data)
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| 90 |
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| 91 | inf.close()
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