32595faba5
* Use wiggle in place of wig in wasi-common This is a rather massive commit that introduces `wiggle` into the picture. We still use `wig`'s macro in `old` snapshot and to generate `wasmtime-wasi` glue, but everything else is now autogenerated by `wiggle`. In summary, thanks to `wiggle`, we no longer need to worry about serialising and deserialising to and from the guest memory, and all guest (WASI) types are now proper idiomatic Rust types. While we're here, in preparation for the ephemeral snapshot, I went ahead and reorganised the internal structure of the crate. Instead of modules like `hostcalls_impl` or `hostcalls_impl::fs`, the structure now resembles that in ephemeral with modules like `path`, `fd`, etc. Now, I'm not requiring we leave it like this, but I reckon it looks cleaner this way after all. * Fix wig to use new first-class access to caller's mem * Ignore warning in proc_exit for the moment * Group unsafes together in args and environ calls * Simplify pwrite; more unsafe blocks * Simplify fd_read * Bundle up unsafes in fd_readdir * Simplify fd_write * Add comment to path_readlink re zero-len buffers * Simplify unsafes in random_get * Hide GuestPtr<str> to &str in path::get * Rewrite pread and pwrite using SeekFrom and read/write_vectored I've left the implementation of VirtualFs pretty much untouched as I don't feel that comfortable in changing the API too much. Having said that, I reckon `pread` and `pwrite` could be refactored out, and `preadv` and `pwritev` could be entirely rewritten using `seek` and `read_vectored` and `write_vectored`. * Add comment about VirtFs unsafety * Fix all mentions of FdEntry to Entry * Fix warnings on Win * Add aux struct EntryTable responsible for Fds and Entries This commit adds aux struct `EntryTable` which is private to `WasiCtx` and is basically responsible for `Fd` alloc/dealloc as well as storing matching `Entry`s. This struct is entirely private to `WasiCtx` and as such as should remain transparent to `WasiCtx` users. * Remove redundant check for empty buffer in path_readlink * Preserve and rewind file cursor in pread/pwrite * Use GuestPtr<[u8]>::copy_from_slice wherever copying bytes directly * Use GuestPtr<[u8]>::copy_from_slice in fd_readdir * Clean up unsafes around WasiCtx accessors * Fix bugs in args_get and environ_get * Fix conflicts after rebase
wasi-common
A Bytecode Alliance project
A library providing a common implementation of WASI hostcalls for re-use in any WASI-enabled runtime.
The wasi-common crate will ultimately serve as a library providing a common implementation of
WASI hostcalls for re-use in any WASI (and potentially non-WASI) runtimes
such as Wasmtime and Lucet.
The library is an adaption of lucet-wasi crate from the Lucet project, and it is currently based on 40ae1df git revision.
Please note that the library requires Rust compiler version at least 1.37.0.
Supported syscalls
*nix
In our *nix implementation, we currently support the entire WASI API with the exception of socket hostcalls:
sock_recvsock_sendsock_shutdown
We expect these to be implemented when network access is standardised.
We also currently do not support the proc_raise hostcall, as it is expected to
be dropped entirely from WASI.
Windows
In our Windows implementation, we currently support the minimal subset of WASI API which allows for running the very basic "Hello world!" style WASM apps. More coming shortly, so stay tuned!
Development hints
When testing the crate, you may want to enable and run full wasm32 integration testsuite. This
requires wasm32-wasi target installed which can be done as follows using rustup
rustup target add wasm32-wasi
Now, you should be able to run the integration testsuite by running cargo test on the
test-programs package with test_programs feature enabled:
cargo test --features test_programs --package test-programs
Third-Party Code
Significant parts of our hostcall implementations are derived from the C implementations in
cloudabi-utils. See LICENSE.cloudabi-utils for license information.