return proper ERRNOs in OpenDirectory.path_open

[ansemjo]

Hello again! ☺️

I was trying to get a Python interpreter to run in the WASI shim and got weird errors like this:

Exception ignored error evaluating path:
Traceback (most recent call last):
  File "<frozen getpath>", line 353, in <module>
OSError: [Errno 65535] Success
Fatal Python error: error evaluating path
Python runtime state: core initialized

Current thread 0x00000000 (most recent call first):
  <no Python frame>

After enabling strace and uncommenting the console.log line, which prints the path, I found that the interpreter was trying to open pyvenv.cfg and pybuilddir.txt. Including those in the shimmed filesystem (even as empty files) allowed the interpreter to continue. However, the underlying problem is probably that the interpreter gets confused by the -1 return code on nonexistent files.

Therefore, this commit uses the (I hope) appropriate ERRNOs in OpenDirectory.path_open, so the interpreter also works when those files do not exist in the filesystem.

It is accompanied by another, functionally independent PR (#38), which shims sock_accept in the imports. Both are needed for Python to work.

[bjorn3]

Yeah, proper error numbers should be returned everywhere. I believe there are a couple of other places where I used -1 as generic error, but this is already an improvement. Thanks!

[bjorn3]

Looks like I forgot to publish a release for your last set of changes. Is this everything you need for now? If so I will publish a new release right now.

[ansemjo]

No worries! I've been using a local fork in the meantime because I've been testing things on and off anyway. ☺️

I think that's all for now, yes. Thanks!

[bjorn3]

Published v0.2.15.