gh-114435: Add test skip when running as admin.

[zooba]

Also makes _winapi.CreateFile unconditionally use Unicode.

• Issue: Windows: test_os.test_stat_inaccessible_file() fails if run as an administrator #114435

[serhiy-storchaka]

Is it different from using open() or os.open()?

[zooba]

Yeah, admin may have additional privileges that make FILE_FLAG_BACKUP_SEMANTICS able to access files that are supposed to be locked away. (One earlier issue with this test is that CreateJunction was enabling the privilege but not disabling it.)

The flags passed here match what stat uses, so we should get equivalent behaviour. Though there's a new quirk that I'm looking into, so we may end up having to just remove the checks in the test that make sure ino/dev are zero, since in some cases they may legitimately get the real value.

[zooba]

@serhiy-storchaka Sorry to make changes just after you approved, but I think we need to remove the skip and instead allow dev/ino to be correctly read. I'm confirming, but I think the new stat API we use on newer Windows is able to read them even in this case, so we don't really have a choice but to allow both values.

The test will still catch wildly invalid results, like the ones that triggered the original issue.

[serhiy-storchaka]

Please don't forget to change the commit message.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 Ubuntu NoGIL 3.x has failed when building commit d91ddff.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/all/#builders/1225/builds/1270) and take a look at the build logs.
4. Check if the failure is related to this commit (d91ddff) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/all/#builders/1225/builds/1270

Failed tests:

• test_capi
• test_eintr
• test_tokenize

Failed subtests:

• test_all - test.test_eintr.EINTRTests.test_all
• test_flock - main.FNTLEINTRTest.test_flock

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File "/home/ubuntu/buildarea/3.x.itamaro-ubuntu-aws.nogil/build/Lib/test/_test_eintr.py", line 535, in test_flock
    self._lock(fcntl.flock, "flock")
    ~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "/home/ubuntu/buildarea/3.x.itamaro-ubuntu-aws.nogil/build/Lib/test/_test_eintr.py", line 517, in _lock
    raise Exception("failed to sync child in %.1f sec" % dt)
Exception: failed to sync child in 300.2 sec


Traceback (most recent call last):
  File "/home/ubuntu/buildarea/3.x.itamaro-ubuntu-aws.nogil/build/Lib/test/test_eintr.py", line 17, in test_all
    script_helper.run_test_script(script)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^
  File "/home/ubuntu/buildarea/3.x.itamaro-ubuntu-aws.nogil/build/Lib/test/support/script_helper.py", line 316, in run_test_script
    raise AssertionError(f"{name} failed")
AssertionError: script _test_eintr.py failed

[zooba]

This PR didn't touch the above listed tests, and it's a nogil buildbot, so someone working on that stuff can look into it.

[miss-islington-app]

Thanks @zooba for the PR 🌮🎉.. I'm working now to backport this PR to: 3.12.
🐍🍒⛏🤖

[bedevere-app]

GH-115851 is a backport of this pull request to the 3.12 branch.