34 lines
1.3 KiB
Markdown
34 lines
1.3 KiB
Markdown
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# Go file permissions test
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by Brandon Dyck <brandon@dyck.us>
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This is an experiment to see how `os.Chmod` and `os.Stat` interact on Windows. The program creates a temporary file, then for each possible set of permissions (0–0777), sets those permissions on the file with `os.Chmod` and checks the resulting permissions with `os.Stat`.
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## Usage
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### `go-perm-test`
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Prints the results as a CSV in the format
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```<expected permissions>,<actual permissions>```
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where each set of permissions is an octal integer.
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### `go-perm-test <filename>`
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Inserts the results into an SQLite database called `filename`.
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There are two objects in the DB schema: a table `result_raw(expected INT, actual INT)` and a view `result`.
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The `result` view breaks down the permissions into separate fields: The raw data are in the `expected` and `actual` columns, 3-bit fields are in `{expected,actual}_{u,g,o}` columns, and 1-bit fields are in `{expected,actual}_{u,g,o}{r,w,x}` columns.
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## Findings
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Permissions as observed through `os.Stat` depend entirely upon the owner's write bit set through `os.Chmod`:
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```
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sqlite> select distinct actual, expected_uw from result;
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actual|expected_uw
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292|0
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438|1
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```
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This obviously isn't an exhaustive treatment of the subject, and I'm not really interested in doing one, but it corraborates [Michal Pristas’s findings.](https://archive.is/RZ8WP)
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