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

[lukostyra]

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.

---

Progress

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Issue

• JDK-8335216: [windows] Missing error check for GetSystemDirectory in glass (Bug - P4)

Reviewers

• Michael Strauß (@mstr2 - Committer)
• Kevin Rushforth (@kevinrushforth - Reviewer)

Reviewing

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[bridgekeeper]

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[openjdk]

@lukostyra This change now passes all automated pre-integration checks.

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

Reviewed-by: mstrauss, kcr

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[mlbridge]

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[kevinrushforth]

I'll review this.

@mstr2 Would you like to be the second reviewer?

/reviewers 2

[openjdk]

@kevinrushforth
The total number of required reviews for this PR (including the jcheck configuration and the last /reviewers command) is now set to 2 (with at least 1 Reviewer, 1 Author).

[mstr2]

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

[kevinrushforth]

Looks good. I ran a quick sanity test as well.

[lukostyra]

/integrate

[openjdk]

Going to push as commit 56e07db.

[openjdk]

@lukostyra Pushed as commit 56e07db.

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