[WIP] Add new custom kernel skeleton

fendermint/vm/interpreter/src/fvm/state/exec.rs

@@ -3,7 +3,6 @@
 
 use cid::Cid;
 use fendermint_vm_genesis::PowerScale;
-use fvm::kernel::filecoin::DefaultFilecoinKernel;
 use fvm::{
     call_manager::DefaultCallManager,
     engine::MultiEngine,
@@ -78,13 +77,15 @@ pub struct FvmUpdatableParams {
 
 pub type MachineBlockstore<DB> = <DefaultMachine<DB, FendermintExterns> as Machine>::Blockstore;
 
+use crate::fvm::state::mycustomkernel::DefaultCustomKernel;
+
 /// A state we create for the execution of all the messages in a block.
 pub struct FvmExecState<DB>
 where
     DB: Blockstore + 'static,
 {
     executor: DefaultExecutor<
-        DefaultFilecoinKernel<
+        DefaultCustomKernel<
             DefaultKernel<DefaultCallManager<DefaultMachine<DB, FendermintExterns>>>,
         >,
     >,

fendermint/vm/interpreter/src/fvm/state/mod.rs

@@ -6,6 +6,7 @@ mod exec;
 pub mod fevm;
 mod genesis;
 pub mod ipc;
+pub mod mycustomkernel;
 mod query;
 pub mod snapshot;
 

fendermint/vm/interpreter/src/fvm/state/mycustomkernel.rs

@@ -0,0 +1,168 @@
+// Copyright 2021-2023 Protocol Labs
+// SPDX-License-Identifier: Apache-2.0, MIT
+
+use fvm::call_manager::CallManager;
+use fvm::gas::Gas;
+use fvm::gas::GasTimer;
+use fvm::gas::PriceList;
+use fvm::kernel::*;
+use fvm::syscalls::bind::BindSyscall;
+use fvm::syscalls::InvocationData;
+use fvm::{
+    ambassador_impl_ActorOps, ambassador_impl_CircSupplyOps, ambassador_impl_CryptoOps,
+    ambassador_impl_DebugOps, ambassador_impl_EventOps, ambassador_impl_GasOps,
+    ambassador_impl_IpldBlockOps, ambassador_impl_LimiterOps, ambassador_impl_MessageOps,
+    ambassador_impl_NetworkOps, ambassador_impl_RandomnessOps, ambassador_impl_SelfOps,
+    DefaultKernel,
+};
+
+use fvm_shared::clock::ChainEpoch;
+use fvm_shared::crypto::signature::*;
+use fvm_shared::randomness::RANDOMNESS_LENGTH;
+use fvm_shared::sys::out::network::NetworkContext;
+use fvm_shared::sys::out::vm::MessageContext;
+use fvm_shared::{address::Address, econ::TokenAmount, sys::SendFlags, ActorID, MethodNum};
+
+use cid::Cid;
+use multihash::MultihashGeneric;
+
+use ambassador::Delegate;
+use wasmtime::Linker;
+
+// define the custom kernel syscall here
+pub trait CustomKernel: Kernel {
+    fn my_custom_syscall(&self) -> Result<()>;
+}
+
+#[derive(Delegate)]
+#[delegate(IpldBlockOps)]
+#[delegate(ActorOps)]
+#[delegate(CircSupplyOps)]
+#[delegate(CryptoOps)]
+#[delegate(DebugOps)]
+#[delegate(EventOps)]
+#[delegate(GasOps)]
+#[delegate(MessageOps)]
+#[delegate(NetworkOps)]
+#[delegate(RandomnessOps)]
+#[delegate(SelfOps)]
+#[delegate(LimiterOps)]
+// we define the implementation of the custom kernel here. We use ambassador to delegate most of the existing syscalls to the default kernel
+pub struct DefaultCustomKernel<K>(pub K)
+where
+    K: Kernel;
+
+// we need to implement the custom kernel trait for the default custom kernel
+impl<C> CustomKernel for DefaultCustomKernel<DefaultKernel<C>>
+where
+    C: CallManager,
+    DefaultCustomKernel<DefaultKernel<C>>: Kernel,
+{
+    fn my_custom_syscall(&self) -> Result<()> {
+        // TODO: Implement the kernel syscall here.
+        Ok(())
+    }
+}
+
+// we need to implement the kernel trait for the default custom kernel, here we simply delegate to the default kernel
+impl<C> Kernel for DefaultCustomKernel<DefaultKernel<C>>
+where
+    C: CallManager,
+{
+    type CallManager = C;
+
+    fn into_inner(self) -> (Self::CallManager, BlockRegistry)
+    where
+        Self: Sized,
+    {
+        self.0.into_inner()
+    }
+
+    fn machine(&self) -> &<Self::CallManager as CallManager>::Machine {
+        self.0.machine()
+    }
+
+    fn send<K: Kernel<CallManager = C>>(
+        &mut self,
+        recipient: &Address,
+        method: u64,
+        params: BlockId,
+        value: &TokenAmount,
+        gas_limit: Option<Gas>,
+        flags: SendFlags,
+    ) -> Result<CallResult> {
+        self.0
+            .send::<Self>(recipient, method, params, value, gas_limit, flags)
+    }
+
+    fn upgrade_actor<K: Kernel<CallManager = Self::CallManager>>(
+        &mut self,
+        new_code_cid: Cid,
+        params_id: BlockId,
+    ) -> Result<CallResult> {
+        self.0.upgrade_actor::<Self>(new_code_cid, params_id)
+    }
+
+    fn new(
+        mgr: C,
+        blocks: BlockRegistry,
+        caller: ActorID,
+        actor_id: ActorID,
+        method: MethodNum,
+        value_received: TokenAmount,
+        read_only: bool,
+    ) -> Self {
+        DefaultCustomKernel(DefaultKernel::new(
+            mgr,
+            blocks,
+            caller,
+            actor_id,
+            method,
+            value_received,
+            read_only,
+        ))
+    }
+}
+
+// we need to implement the syscall handler for the default custom kernel which binds our syscalls to the wasmtime linker
+impl<C> SyscallHandler<DefaultCustomKernel<DefaultKernel<C>>>
+    for DefaultCustomKernel<DefaultKernel<C>>
+where
+    C: CallManager,
+{
+    fn bind_syscalls(
+        &self,
+        linker: &mut Linker<InvocationData<DefaultCustomKernel<DefaultKernel<C>>>>,
+    ) -> anyhow::Result<()> {
+        self.0.bind_syscalls(linker)?;
+
+        // Now bind our custom syscalls
+        linker.bind("my_custom_kernel", "my_custom_syscall", my_custom_syscall)?;
+
+        Ok(())
+    }
+}
+
+// this is the actual syscall implementation as registered in bind_syscalls
+pub fn my_custom_syscall(context: fvm::syscalls::Context<'_, impl CustomKernel>) -> Result<()> {
+    context.kernel.my_custom_syscall()?;
+    Ok(())
+}
+
+pub mod sdk {
+    // This is the direct sdk call the wasm actor calls
+    pub fn my_custom_syscall() {
+        unsafe {
+            sys::my_custom_syscall().unwrap();
+        }
+    }
+
+    pub mod sys {
+        use fvm_sdk::fvm_syscalls;
+
+        fvm_syscalls! {
+            module = "my_custom_kernel";
+            pub fn my_custom_syscall() -> Result<()>;
+        }
+    }
+}