ebb693aa18
* Treat `-` as an alias to `/dev/stdin` This applies to unix targets only, as Windows does not have an appropriate alternative. * Add tests for piped modules from stdin This applies to unix targets only, as Windows does not have an appropriate alternative. * Move precompiled module detection into wasmtime Previously, wasmtime-cli checked the module to be loaded is precompiled or not, by pre-opening the given file path to check if the "\x7FELF" header exists. This commit moves this branch into the `Module::from_trusted_file`, which is only invoked with `--allow-precompiled` flag on CLI. The initial motivation of the commit is, feeding a module to wasmtime from piped inputs, is blocked by the pre-opening of the module. The `Module::from_trusted_file`, assumes the --allow-precompiled flag so there is no piped inputs, happily mmap-ing the module to test if the header exists. If --allow-precompiled is not supplied, the existing `Module::from_file` will be used, without the additional header check as the precompiled modules are intentionally not allowed on piped inputs for security measures. One caveat of this approach is that the user may be confused if he or she tries to execute a precompiled module without --allow-precompiled, as wasmtime shows an 'input bytes aren't valid utf-8' error, not directly getting what's going wrong. So this commit includes a hack-ish workaround for this. Thanks to @jameysharp for suggesting this idea with a detailed guidance.
wasmtime
A standalone runtime for WebAssembly
A Bytecode Alliance project
Guide | Contributing | Website | Chat
Installation
The Wasmtime CLI can be installed on Linux and macOS with a small install script:
curl https://wasmtime.dev/install.sh -sSf | bash
Windows or otherwise interested users can download installers and binaries directly from the GitHub Releases page.
Example
If you've got the Rust compiler installed then you can take some Rust source code:
fn main() {
println!("Hello, world!");
}
and compile/run it with:
$ rustup target add wasm32-wasi
$ rustc hello.rs --target wasm32-wasi
$ wasmtime hello.wasm
Hello, world!
Features
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Fast. Wasmtime is built on the optimizing Cranelift code generator to quickly generate high-quality machine code either at runtime or ahead-of-time. Wasmtime is optimized for efficient instantiation, low-overhead calls between the embedder and wasm, and scalability of concurrent instances.
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Secure. Wasmtime's development is strongly focused on correctness and security. Building on top of Rust's runtime safety guarantees, each Wasmtime feature goes through careful review and consideration via an RFC process. Once features are designed and implemented, they undergo 24/7 fuzzing donated by Google's OSS Fuzz. As features stabilize they become part of a release, and when things go wrong we have a well-defined security policy in place to quickly mitigate and patch any issues. We follow best practices for defense-in-depth and integrate protections and mitigations for issues like Spectre. Finally, we're working to push the state-of-the-art by collaborating with academic researchers to formally verify critical parts of Wasmtime and Cranelift.
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Configurable. Wasmtime uses sensible defaults, but can also be configured to provide more fine-grained control over things like CPU and memory consumption. Whether you want to run Wasmtime in a tiny environment or on massive servers with many concurrent instances, we've got you covered.
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WASI. Wasmtime supports a rich set of APIs for interacting with the host environment through the WASI standard.
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Standards Compliant. Wasmtime passes the official WebAssembly test suite, implements the official C API of wasm, and implements future proposals to WebAssembly as well. Wasmtime developers are intimately engaged with the WebAssembly standards process all along the way too.
Language Support
You can use Wasmtime from a variety of different languages through embeddings of the implementation:
- Rust - the
wasmtimecrate - C - the
wasm.h,wasi.h, andwasmtime.hheaders, CMake orwasmtimeConan package - C++ - the
wasmtime-cpprepository or usewasmtime-cppConan package - Python - the
wasmtimePyPI package - .NET - the
WasmtimeNuGet package - Go - the
wasmtime-gorepository
Documentation
📚 Read the Wasmtime guide here! 📚
The wasmtime guide is the best starting point to learn about what Wasmtime can do for you or help answer your questions about Wasmtime. If you're curious in contributing to Wasmtime, it can also help you do that!
It's Wasmtime.