42 lines
1.9 KiB
Plaintext
42 lines
1.9 KiB
Plaintext
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Notes on using the --osx-hfs option when running mkisofs on MacOS X
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mkisofs does not use any of the MacOS APIs to access files - it uses
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standard (POSIX style) library calls. Under normal circumstances, all
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mkisofs will 'see' is the data fork of files on an HFS (or HFS+) file system.
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However, Apple have provided a way for POSIX style applications to
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access the resource fork - using the following syntax:
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If a file exists on an HFS volume with the name 'foo', then the resource fork
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can be accessed using the file name 'foo/rsrc' or foo/..namedfork/rsrc'
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(the data fork can also be accessed using 'foo/..namedfork/data').
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These 'pseudo' file names are not normally visible in a directory - unless
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you access them directly (e.g. 'ls -l */rsrc etc).
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To access the finder information, Apple have provided an undocumented library
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function called getattrlist(). Fortunately there are example of its usage
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in the Darwin (MacOS kernel) source code.
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Although MacOS X can use HFS(+) as its file system, Apple have decided to
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move away from using HFS to store finder info and resource data - for
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example, the TYPE of a file may be based on its file name extension and the
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TYPE field in the finder info empty.
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mkisofs knows nothing about these file name extension mappings, so if the
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--osx-hfs option is used and the source files are on MacOS X HFS(+) volumes,
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by the fact that they are HFS files, they will get identified as 'MacOS X HFS'
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and the resulting file on the output CD image will have empty TYPE and CREATOR
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fields.
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Therefore, if the input finderinfo is blank and the the resource fork is
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empty, mkisofs will assume the input file is not a 'real' HFS file - which
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means the TYPE and CREATOR may then be set using the file's magic number or
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mkisofs' file name extension mapping.
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The only real benefit of using the --osx-hfs option is when the source files
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are on an OS9 or earlier HFS or HFS+ volume e.g. an existing HFS CD.
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James Pearson 3-Jul-2002
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