RFR: 8335216: [windows] Missing error check for GetSystemDirectory in glass

[Michael Strauß]

On Mon, 8 Jul 2024 14:24:27 GMT, Lukasz Kostyra <lkostyra at openjdk.org> wrote:

> When GetSystemDirectory does not have enough space to output a path to Windows' system directory, it will return a different value than 0 (more notably, the amount of bytes actually needed including null terminator). This was not checked, so the very rare hypothetical situation where Windows' system directory is different than the "standard" `C:\Windows` and longer than MAX_PATH was not properly handled.
> 
> For now I simply changed the code to print an error and exit. This could be improved further to instead dynamically allocate space for the system directory though.
> 
> Other changes, also mentioned in the issue:
> - We use `wchar_t` explicitly here, so I changed `GetSystemDirectory` to `GetSystemDirectoryW` to ensure the code compiles even without UNICODE being defined
> - `wcscat_s` can potentially fail for the same reasons as above, so this situation is also handled now.

I've checked the specification of `GetSystemDirectoryW` and `wcscat_s`. The patch will correctly catch failure cases.

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Marked as reviewed by mstrauss (Committer).

PR Review: https://git.openjdk.org/jfx/pull/1498#pullrequestreview-2164023380