* Introduce WasiCtxBuilderError error type
`WasiCtxBuilderError` is the `wasi-common` client-facing error type
which is exclusively thrown when building a new `WasiCtx` instance.
As such, building such an instance should not require the client to
understand different WASI errno values as was assumed until now.
This commit is a first step at streamlining error handling in
`wasi-common` and makes way for the `wiggle` crate.
When adding the `WasiCtxBuilderError`, I've had to do two things of
notable importance:
1. I've removed a couple of `ok_or` calls in `WasiCtxBuilder::build`
and replaced them with `unwrap`s, following the same pattern in
different builder methods above. This is fine since we _always_
operate on non-empty `Option`s in `WasiCtxBuilder` thus `unwrap`ing
will never fail. On the other hand, this might be a good opportunity
to rethink the structure of our builder, and how we good remove
the said `Option`s especially since we always populate them with
empty containers to begin with. I understand this is to make
chaining of builder methods easier which take and return `&mut self`
and the same applies to `WasiCtxBuilder::build(&mut self)` method,
but perhaps it would more cleanly signal the intentions if we simply
moved `WasiCtxBuilder` instance around. Food for thought!
2. Methods specific to determining rights of passed around `std::fs::File`
objects when populating `WasiCtx` `FdEntry` entities now return
`io::Error` directly so that we can reuse them in `WasiCtxBuilder` methods
(returning `WasiCtxBuilderError` error type), and in syscalls
(returning WASI errno).
* Return WasiError directly in syscalls
Also, removes `error::Error` type altogether. Now, `io::Error` and
related are automatically converted to their corresponding WASI
errno value encapsulated as `WasiError`.
While here, it made sense to me to move `WasiError` to `wasi` module
which will align itself well with the upcoming changes introduced
by `wiggle`. To different standard `Result` from WASI specific, I've
created a helper alias `WasiResult` also residing in `wasi` module.
* Update wig
* Add from ffi::NulError and pass context to NotADirectory
* Add dummy commit to test CI
* Move filetime module to yanix
I've noticed that we could replace every occurrence of `crate::Result`
in `filetime` mods with `io::Result`, so I thought why not move it
to `yanix` and get rid off a lot of unnecessary code duplication
within `wasi-common`. Now, ideally I'd have our `filetime` modifications
backported to Alex's [`filetime`] crate, but one step at a time
(apologies Alex, I was meant to backport this ages ago, just didn't
find the time yet... :-().
Anyway, this commit does just that; i.e., moves the `filetime` modules
into `yanix` which seems a better fit for this type of code.
[`filetime`]: https://github.com/alexcrichton/filetime
There is one caveat here. On Emscripten, converting between `filetime::Filetime`
and `libc::timespec` appears to be lossy, at least as far as the
types are concerned. Now, `filetime::Filetime`'s seconds field is
`i64` while nanoseconds field is `u32`, while Emscripten's
`libc::timespec` requires both to be `i32` width. This might actually
not be a problem since I don't think it's possible to fill `filetime::Filetime`
struct with values of width wider than `i32` since Emscripten is 32bit
but just to be on the safe side, we do a `TryInto` conversion, log
the error (if any), and return `libc::EOVERFLOW`.
* Run cargo fmt
* Use i64::from instead of as cast
* Compile wasi-common to Emscripten
This commit enables cross-compiling of `wasi-common` to Emscripten. To achieve
this, this commit does quite a bit reshuffling in the existing codebase. Namely,
* rename `linux` modules in `wasi-common` and `yanix` to `linux_like` -- this is
needed so that we can separate out logic specific to Linux and Emscripten out
* tweak `dir` module in `yanix` to support Emscripten -- in particular, the main
change involves `SeekLoc::from_raw` which has to be now host-specific, and is now
fallible
* tweak `filetime` so that in Emscripten we never check for existence of `utimensat`
at runtime since we are guaranteed for it to exist by design
* since `utimes` and `futimes` are not present in Emscripten, move them into a separate
module, `utimesat`, and tag it cfg-non-emscripten only
* finally, `to_timespec` is now fallible since on Emscripten we have to cast number of
seconds, `FileTime::seconds` from `i64` to `libc::c_long` which resolves to `i32`
unlike on other nixes
* Fix macos build
* Verify wasi-common compiles to Emscripten
This commit adds `emscripten` job to Github Actions which installs
`wasm32-unknown-emscripten` target, and builds `wasi-common` crate.
* Use #[path] to cherry-pick mods for Emscripten
This commit effectively reverses the reorg introduced in 145f4a5
in that it ditches `linux_like` mod for separate mods `linux` and
`emscripten` which are now on the same crate level, and instead,
pulls in common bits from `linux` using the `#[path = ..]` proc
macro.
* Add yanix crate
This commit adds `yanix` crate as a Unix dependency for `wasi-common`.
`yanix` stands for Yet Another Nix crate and is exactly what the name
suggests: a crate in the spirit of the `nix` crate, but which takes a different
approach, using lower-level interfaces with less abstraction, so that it fits
better with its main use case, implementation of WASI syscalls.
* Replace nix with yanix crate
Having introduced `yanix` crate as an in-house replacement for the
`nix` crate, this commit makes the necessary changes to `wasi-common`
to depend _only_ on `yanix` crate.
* Address review comments
* make `fd_dup` unsafe
* rename `get_fd` to `get_fd_flags`, etc.
* reuse `io::Error::last_os_error()` to get the last errno value
* Address more comments
* make all `fcntl` fns unsafe
* adjust `wasi-common` impl appropriately
* Make all fns operating on RawFd unsafe
* Fix linux build
* Address more comments
* Dynamically load utimensat if exists on the host
This commit introduces a change to file time management for *nix based
hosts in that it firstly tries to load `utimensat` symbol, and if it
doesn't exist, then falls back to `utimes` instead. This change is
borrowing very heavily from [filetime] crate, however, it introduces a
couple of helpers and methods specific to WASI use case (or more
generally, to a use case which requires modifying times of entities
specified by a pair `(DirFD, RelativePath)` rather than the typical
file time specification based only absolute path or raw file descriptor
as is the case with [filetime] crate. The trick here is, that on kernels
which do not have `utimensat` symbol, this implementation emulates this
behaviour by a combination of `openat` and `utimes`.
This commit also is meant to address #516.
[filetime]: https://github.com/alexcrichton/filetime
* Fix symlink NOFOLLOW flag setting
* Add docs and specify UTIME_NOW/OMIT on Linux
Previously, we relied on [libc] crate for `UTIME_NOW` and `UTIME_OMIT`
constants on Linux. However, following the convention assumed in
[filetime] crate, this is now changed to directly specified by us
in our crate.
[libc]: https://github.com/rust-lang/libc
[filetime]: https://github.com/alexcrichton/filetime
* Refactor UTIME_NOW/OMIT for BSD
* Address final discussion points
