46 lines
1.8 KiB
Text
46 lines
1.8 KiB
Text
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#------------------------------------------------------------------------------
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# $File: dwarfs,v 1.2 2023/05/23 13:37:32 christos Exp $
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# dwarfs: file(1) magic for DwarFS File System Image files
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# URL: https://github.com/mhx/dwarfs for details about DwarFS
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# From: Marcus Holland-Moritz <github@mhxnet.de>
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#### DwarFS Version Macro
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0 name dwarfsversion
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>&0 byte x \b, version %d
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>&1 byte x \b.%d
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#### DwarFS Compression Macro
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0 name dwarfscompression
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>&0 leshort =0 \b, uncompressed
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>&0 leshort =1 \b, LZMA compression
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>&0 leshort =2 \b, ZSTD compression
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>&0 leshort =3 \b, LZ4 compression
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>&0 leshort =4 \b, LZ4HC compression
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>&0 leshort =5 \b, BROTLI compression
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#### DwarFS files without header
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## We first check against a DWARFS magic at the start of the file, then
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## validate by checking the block count / section type to be all zeros
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## for the first block. Finally, we check that the *next* block also
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## has the correct DWARFS magic.
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0 string DWARFS
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>&0x2A string/b \0\0\0\0\0\0
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>>&(&0x02.q+0x0A) string DWARFS DwarFS File System Image
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>>>&0 use dwarfsversion
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>>&0 use dwarfscompression
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#### DwarFS files with header
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## We search for a DWARFS magic in the first 64k of the file (images with
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## headers longer than 64k won't be recognized), then validate by checking
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## the block count / section type to be all zeros for the first block.
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## Finally, we check that the *next* block also has the correct DWARFS magic.
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## If we find a DWARFS magic that doesn't pass validation, we continue with
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## an indirect match recursively.
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1 search/65536/b DWARFS
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>&0x2A string/b \0\0\0\0\0\0
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>>&(&0x02.q+0x0A) string DWARFS DwarFS File System Image (with header)
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>>>&0 use dwarfsversion
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>>&0 use dwarfscompression
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>&-1 indirect x
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