Fix GetModuleFileName in GetProcessPath

[huoyaoyuan]

Fixes #110800

[jkotas]

Ideally, we would have a test for this. Unfortunately, it is not easy to build one because of other issues in the end-to-end handling of longs paths (#58492).

Have you done ad-hoc testing for this? Does the API return the path with or without \\?\ prefix?

[huoyaoyuan]

Ad-hoc testing passed, path is returned without \\?\ prefix:

Explorer refuses to create folder or file exceeding MAX_PATH, and PowerShell can't start process exceeding MAX_PATH. cmd can launch the executable.

[huoyaoyuan]

Does there need to be a bound to prevent integer overflow? It would cause infinite loop again if path length exceeds 2^30, which is unlikely to happen in any situation.

[jkotas]

It would cause infinite loop again if path length exceeds 2^30, which is unlikely to happen in any situation.

I do not think it would lead to infinite loop. EnsureCapacity would throw an exception once there is an overflow and it gets called with negative capacity.

[jborean93]

Ad-hoc testing passed, path is returned without \?\ prefix:

That's interesting, in my manual test in #110800 using PInvoke to call GetModulePath it returned the \\?\ prefix. I wonder if it's due to how the executable was started because I was setting the path to CreateProcess with that prefix.