Struct wasmtime_wasi::preview2::WasiCtxBuilder

pub struct WasiCtxBuilder { /* private fields */ }

Implementations

impl WasiCtxBuilder

pub fn new() -> Self

Creates a builder for a new context with default parameters set.

The current defaults are:

• stdin is closed
• stdout and stderr eat all input but it doesn’t go anywhere
• no env vars
• no arguments
• no preopens
• clocks use the host implementation of wall/monotonic clocks
• RNGs are all initialized with random state and suitable generator quality to satisfy the requirements of WASI APIs.

These defaults can all be updated via the various builder configuration methods below.

Note that each builder can only be used once to produce a WasiCtx. Invoking the build method will panic on the second attempt.

pub fn stdin(&mut self, stdin: impl StdinStream + 'static) -> &mut Self

pub fn stdout(&mut self, stdout: impl StdoutStream + 'static) -> &mut Self

pub fn stderr(&mut self, stderr: impl StdoutStream + 'static) -> &mut Self

pub fn inherit_stdin(&mut self) -> &mut Self

pub fn inherit_stdout(&mut self) -> &mut Self

pub fn inherit_stderr(&mut self) -> &mut Self

pub fn inherit_stdio(&mut self) -> &mut Self

pub fn envs(&mut self, env: &[(impl AsRef<str>, impl AsRef<str>)]) -> &mut Self

pub fn env(&mut self, k: impl AsRef<str>, v: impl AsRef<str>) -> &mut Self

pub fn args(&mut self, args: &[impl AsRef<str>]) -> &mut Self

pub fn arg(&mut self, arg: impl AsRef<str>) -> &mut Self

pub fn preopened_dir( &mut self, dir: Dir, perms: DirPerms, file_perms: FilePerms, path: impl AsRef<str> ) -> &mut Self

pub fn secure_random( &mut self, random: impl RngCore + Send + 'static ) -> &mut Self

Set the generator for the secure random number generator to the custom generator specified.

Note that contexts have a default RNG configured which is a suitable generator for WASI and is configured with a random seed per-context.

Guest code may rely on this random number generator to produce fresh unpredictable random data in order to maintain its security invariants, and ideally should use the insecure random API otherwise, so using any prerecorded or otherwise predictable data may compromise security.

pub fn insecure_random( &mut self, insecure_random: impl RngCore + Send + 'static ) -> &mut Self

pub fn insecure_random_seed(&mut self, insecure_random_seed: u128) -> &mut Self

pub fn wall_clock(&mut self, clock: impl HostWallClock + 'static) -> &mut Self

pub fn monotonic_clock( &mut self, clock: impl HostMonotonicClock + 'static ) -> &mut Self

pub fn inherit_network(&mut self) -> &mut Self

Allow all network addresses accessible to the host

pub fn socket_addr_check<F>(&mut self, check: F) -> &mut Self

where F: Fn(&SocketAddr, SocketAddrUse) -> bool + Send + Sync + 'static,

A check that will be called for each socket address that is used.

Returning true will permit socket connections to the SocketAddr, while returning false will reject the connection.

pub fn allow_ip_name_lookup(&mut self, enable: bool) -> &mut Self

Allow usage of wasi:sockets/ip-name-lookup

pub fn allow_udp(&mut self, enable: bool) -> &mut Self

Allow usage of UDP

pub fn allow_tcp(&mut self, enable: bool) -> &mut Self

Allow usage of TCP

pub fn build(&mut self) -> WasiCtx

Uses the configured context so far to construct the final WasiCtx.

Note that each WasiCtxBuilder can only be used to “build” once, and calling this method twice will panic.

Panics

Panics if this method is called twice.