Files
wasmtime/crates/wasi-common
Dan Gohman 1f9d764d5d Support fd_fdstat_get and fd_renumber on stdin/stdout/stderr (#631)
* Support fd_fdstat_get on stdin/stdout/stderr.

Add a routine for obtaining an `OsFile` containing a file descriptor for
stdin/stdout/stderr so that we can do fd_fdstat_get on them.

* Add a testcase for fd_fdstat_get etc. on stdin etc.

* Don't dup file descriptors in fd_renumber.

* Fix compilation on macOS

* Rename OsFile to OsHandle

This commits renames `OsFile` to `OsHandle` which seems to make
more sense semantically as it is permitted to hold a valid OS handle
to OS entities other than simply file/dir (e.g., socket, stream, etc.).
As such, this commit also renames methods on `Descriptor` struct
from `as_actual_file` to `as_file` as this in reality does pertain
ops on FS entities such as files/dirs, and `as_file` to `as_os_handle`
as in this case it can be anything, from file, through a socket, to
a stream.

* Fix compilation on Linux

* Introduce `OsHandleRef` for borrowing OS resources.

To prevent a `ManuallyDrop<OsHandleRef>` from outliving the resource it
holds on to, create an `OsHandleRef` class parameterized on the lifetime
of the `Descriptor`.

* Fix scoping to pub-priv and backport to snapshot_0
2019-11-28 14:36:18 +01:00
..
2019-11-08 06:35:40 -08:00
2019-11-08 06:35:40 -08:00

wasi-common

A Bytecode Alliance project

A library providing a common implementation of WASI hostcalls for re-use in any WASI-enabled runtime.

Crates.io version Download docs.rs docs

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_recv
  • sock_send
  • sock_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.