wasmer_wasix/syscalls/wasi/
proc_exit.rs

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use super::*;
use crate::syscalls::*;

/// ### `proc_exit()`
/// Terminate the process normally. An exit code of 0 indicates successful
/// termination of the program. The meanings of other values is dependent on
/// the environment.
/// Inputs:
/// - `ExitCode`
///   Exit code to return to the operating system
#[instrument(level = "trace", skip_all)]
pub fn proc_exit<M: MemorySize>(
    mut ctx: FunctionEnvMut<'_, WasiEnv>,
    code: ExitCode,
) -> Result<(), WasiError> {
    WasiEnv::do_pending_operations(&mut ctx)?;

    debug!(%code);

    // If we are in a vfork we need to return to the point we left off
    if let Some(mut vfork) = ctx.data_mut().vfork.take() {
        tracing::debug!(
            parent_pid = %vfork.env.process.pid(),
            child_pid = %ctx.data().process.pid(),
            "proc_exit from vfork, returning control to parent process"
        );

        // Prepare the child env for teardown by closing its FDs
        InlineWaker::block_on(
            unsafe { ctx.data().get_memory_and_wasi_state(&ctx, 0) }
                .1
                .fs
                .close_all(),
        );

        // Restore the WasiEnv to the point when we vforked
        vfork.env.swap_inner(ctx.data_mut());
        std::mem::swap(vfork.env.as_mut(), ctx.data_mut());
        let mut child_env = *vfork.env;
        child_env.owned_handles.push(vfork.handle);

        // Terminate the child process
        child_env.process.terminate(code);

        // Jump back to the vfork point and current on execution
        let child_pid = child_env.process.pid();
        let rewind_stack = vfork.rewind_stack.freeze();
        let store_data = vfork.store_data;
        unwind::<M, _>(ctx, move |mut ctx, _, _| {
            // Now rewind the previous stack and carry on from where we did the vfork
            match rewind::<M, _>(
                ctx,
                None,
                rewind_stack,
                store_data,
                ForkResult {
                    pid: child_pid.raw() as Pid,
                    ret: Errno::Success,
                },
            ) {
                Errno::Success => OnCalledAction::InvokeAgain,
                err => {
                    warn!("fork failed - could not rewind the stack - errno={}", err);
                    OnCalledAction::Trap(Box::new(WasiError::Exit(err.into())))
                }
            }
        })?;
        return Ok(());
    }

    // Otherwise just exit
    Err(WasiError::Exit(code))
}