This commit fixes a subtle bug in `fd_readdir` implementation on
BSD-style nixes. In particular, the bug only resurfaced when testing in
release mode, and I can only assume it was due to a unlucky combination
of compiler optimizations and at first sight correct casting of `d_name`
pointer from `const* i8` to `const* u8`. This is now fixed by first
converting `d_name` to `std::str` by using `std::ffi::CStr::to_str`, and
then using the resultant `std::str` to copy the properly validated `u8`
contents into the Wasm buffer.
Furthermore, this commit fixes incorrect handling of the `readdir` loop
break condition. Although undocumented in BSD man pages, the signalling
is the same as on Linux where a null ptr returned by `readdir` signals
the end of the dir stream when the errno code has not changed since
before calling `readdir` inside a loop. Upon a fault such as an invalid
file descriptor, the errno *will* change after executing `readdir`.
Some wasi-common tests assume that stdin is never ready to be read, but
on CI stdin is closed so it's always ready to be read. Work around this
by guaranteeing that wasi-common tests always have an unreadable stdin
pipe by creating our own pipe.
This commit merges [CraneStation/wasi-common] repo as a subdir of
this repo while preserving **all** of git history. There is an
initiative to pull `wasi-common` into [CraneStation/wasmtime], and
[CraneStation/wasmtime] becoming a monorepo. This came about for
several reasons with a common theme of convenience, namely,
having a monorepo:
1. cleans up the problem of dependencies (as we have seen first
hand with dependabot enabled, it can cause some grief)
2. completely removes the problem of syncing the closely dependent
repos (e.g., updating `wasi-common` with say a bugfix generally
implies creating a "sync" commit for pulling in the changes into
the "parent" repo, in this case, `wasmtime`)
3. mainly for the two reasons above, makes publishing to crates.io
easier
4. hopefully streamlines the process of getting the community
involved in contributing to `wasi-common` as now everything
is one place
[CraneStation/wasi-common]: https://github.com/CraneStation/wasi-common
[CraneStation/wasmtime]: https://github.com/CraneStation/wasmtime
