Internal modules `memory` and `host` can indeed be internal hidden
behind public-private visibility as `wasmtime-wasi` has already
been updated not to use the said modules (see
CraneStation/wasmtime#298).
Functions which trust that their arguments are valid raw file descriptors
or raw handles should be marked unsafe, because these arguments are
passed unchecked to I/O routines.
* Fix fd_readdir on BSD-style nixes
The fix was tested on Darwin-XNU and FreeBSD. The change introduces
thread-safe cache of (RawFd, *mut libc::DIR) pairs so that
libc::fdopendir syscall is called only once when invoking fd_readdir
for the first time, and then the pointer to the directory stream,
*mut libc::DIR, is reused until the matching raw file descriptor
is closed.
This fix allows then correct use (and matching to the implementation
on Linux kernels) of libc::seekdir and libc::rewinddir to seek through
and rewind the existing directory stream, *mut libc::DIR, which
otherwise seems to be reset/invalidated every time libc::fdopendir
is called (unlike on Linux, where this behaviour is not observed).
* Store dir stream as part of the FdEntry's Descriptor
* Move bsd specifics into separate module
* Add todo comments and fix formatting
* Refactor int conversions
* Emphasise in debug logs that we're looking at fd_readdir entry
* Change visibility of FdEntry and related to public-private
* Rewrite creating DirStream for the first time
* when executed twice in a row, need to manually reset the stream
by calling seekdir with __WASI_DIRCOOKIE_START, if __WASI_DIRCOOKIE_START
was specified
* fix mapping between d_type and __wasi_filetype_t
* include minor refactor - removes use of wasm32 module on the
host's side
