`System.Directory.getPermissions` fails on read-only filesystem

Alain O'Dea reports in an email that:

Prelude> System.Directory.getPermissions "/usr/bin/ld"
*** Exception: /usr/bin/ld: fileAccess: permission denied (Read-only file system)

That seems wrong.

An access(*, W_OK) syscall by design should return EROFS on a read-only file system by specification.

This breaks Cabal on SmartOS since /usr is read-only by design and Cabal calls getPermissions "/usr/bin/ld".

Trac metadata

Trac field	Value
Version	7.6.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	high
Resolution	Unresolved
Component	libraries/directory
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