diff --git a/crates/xrpl-host-functions/src/lib.rs b/crates/xrpl-host-functions/src/lib.rs index c2e5de4827..a9ff193d3f 100644 --- a/crates/xrpl-host-functions/src/lib.rs +++ b/crates/xrpl-host-functions/src/lib.rs @@ -111,6 +111,11 @@ host_functions! { #[wasm_name = "parent_ldgr_time"] fn get_parent_ledger_time(&self, out: &mut [u8]) -> HostResult; + /// The hash of the parent (last-closed) ledger, as 32 bytes. + #[gas = 60] + #[wasm_name = "parent_ldgr_hash"] + fn get_parent_ledger_hash(&self, out: &mut [u8]) -> HostResult; + /// The serialized bytes of one field of the current (escrow) ledger object. #[gas = 70] #[wasm_name = "home_le_field"] diff --git a/crates/xrpl-host-functions/tests/generated_abi.rs b/crates/xrpl-host-functions/tests/generated_abi.rs index 16e8336f39..ce306e9093 100644 --- a/crates/xrpl-host-functions/tests/generated_abi.rs +++ b/crates/xrpl-host-functions/tests/generated_abi.rs @@ -35,6 +35,10 @@ impl HostFunctions for FakeHost { put(out, &9u32.to_le_bytes()) } + fn get_parent_ledger_hash(&self, out: &mut [u8]) -> HostResult { + put(out, &[0xab; HASH_LEN]) + } + /// Fails on a field it doesn't know, so the error channel is exercised too. fn get_current_ledger_obj_field(&self, field: i32, out: &mut [u8]) -> HostResult { if field < 0 { @@ -71,6 +75,8 @@ fn the_trait_is_implementable() { assert_eq!(out[..4], [7, 0, 0, 0]); assert_eq!(host.get_parent_ledger_time(&mut out), Ok(4)); assert_eq!(out[..4], [9, 0, 0, 0]); + assert_eq!(host.get_parent_ledger_hash(&mut out), Ok(HASH_LEN)); + assert_eq!(out[0], 0xab); assert_eq!(host.get_current_ledger_obj_field(3, &mut out), Ok(1)); assert_eq!(out[0], 3); assert_eq!(host.sha512_half(b"abc", &mut out), Ok(HASH_LEN)); @@ -142,6 +148,7 @@ fn the_spec_table_matches_the_declarations() { [ ("ldgr_index", 60), ("parent_ldgr_time", 60), + ("parent_ldgr_hash", 60), ("home_le_field", 70), ("sha512_half", 2000), ("trace", 500), diff --git a/crates/xrpl-wasm-vm-ffi/src/lib.rs b/crates/xrpl-wasm-vm-ffi/src/lib.rs index 9a68c16c9c..00939b6e26 100644 --- a/crates/xrpl-wasm-vm-ffi/src/lib.rs +++ b/crates/xrpl-wasm-vm-ffi/src/lib.rs @@ -163,6 +163,10 @@ mod ffi { #[cxx_name = "getParentLedgerTime"] fn get_parent_ledger_time(self: &HostContext, out: &mut [u8]) -> i32; + #[namespace = "xrpl"] + #[cxx_name = "getParentLedgerHash"] + fn get_parent_ledger_hash(self: &HostContext, out: &mut [u8]) -> i32; + #[namespace = "xrpl"] #[cxx_name = "getCurrentLedgerObjField"] fn get_current_ledger_obj_field(self: &HostContext, field: i32, out: &mut [u8]) -> i32; @@ -220,6 +224,10 @@ impl HostFunctions for CxxHost<'_> { bytes_written(self.ctx.get_parent_ledger_time(out)) } + fn get_parent_ledger_hash(&self, out: &mut [u8]) -> HostResult { + bytes_written(self.ctx.get_parent_ledger_hash(out)) + } + fn get_current_ledger_obj_field(&self, field: i32, out: &mut [u8]) -> HostResult { bytes_written(self.ctx.get_current_ledger_obj_field(field, out)) } diff --git a/crates/xrpl-wasm-vm/src/abi.rs b/crates/xrpl-wasm-vm/src/abi.rs index b6c828598a..8d018454e5 100644 --- a/crates/xrpl-wasm-vm/src/abi.rs +++ b/crates/xrpl-wasm-vm/src/abi.rs @@ -191,6 +191,9 @@ mod tests { fn get_parent_ledger_time(&self, _out: &mut [u8]) -> HostResult { unreachable!("no unit test in this module calls the host") } + fn get_parent_ledger_hash(&self, _out: &mut [u8]) -> HostResult { + unreachable!("no unit test in this module calls the host") + } fn get_current_ledger_obj_field(&self, _field: i32, _out: &mut [u8]) -> HostResult { unreachable!("no unit test in this module calls the host") } diff --git a/crates/xrpl-wasm-vm/src/register.rs b/crates/xrpl-wasm-vm/src/register.rs index 28a7c5830d..89678afe26 100644 --- a/crates/xrpl-wasm-vm/src/register.rs +++ b/crates/xrpl-wasm-vm/src/register.rs @@ -48,6 +48,19 @@ pub(crate) fn register_host_functions( }) }, ), + HostFunctionSpec::GetParentLedgerHash => linker.func_wrap( + HOST_MODULE, + op.wasm_name(), + |mut caller: Caller<'_, VmState<'_>>, + out_ptr: i32, + out_len: i32| + -> Result { + charged(&mut caller, HostFunctionSpec::GetParentLedgerHash, |c| { + let out = Region::new(out_ptr, out_len); + write_into(c, out, |host, out| host.get_parent_ledger_hash(out)) + }) + }, + ), HostFunctionSpec::GetCurrentLedgerObjField => linker.func_wrap( HOST_MODULE, op.wasm_name(), diff --git a/crates/xrpl-wasm-vm/tests/budgets.rs b/crates/xrpl-wasm-vm/tests/budgets.rs index fabe7c86f6..ff732879b4 100644 --- a/crates/xrpl-wasm-vm/tests/budgets.rs +++ b/crates/xrpl-wasm-vm/tests/budgets.rs @@ -61,6 +61,11 @@ fn call_for(op: HostFunctionSpec) -> Call { "(call $parent_ldgr_time (i32.const 0) (i32.const 4))", 2, ), + HostFunctionSpec::GetParentLedgerHash => ( + import::PARENT_LDGR_HASH, + "(call $parent_ldgr_hash (i32.const 0) (i32.const 32))", + 2, + ), HostFunctionSpec::GetCurrentLedgerObjField => ( import::HOME_LE_FIELD, "(call $home_le_field (i32.const 1) (i32.const 0) (i32.const 4))", diff --git a/crates/xrpl-wasm-vm/tests/host_calls.rs b/crates/xrpl-wasm-vm/tests/host_calls.rs index c6981e1f12..1b1956e4a9 100644 --- a/crates/xrpl-wasm-vm/tests/host_calls.rs +++ b/crates/xrpl-wasm-vm/tests/host_calls.rs @@ -49,6 +49,31 @@ fn parent_ldgr_time_writes_the_close_time_where_the_guest_asked() { assert_eq!(status(&wat, &host), 4, "the byte count"); } +/// A 32-byte value (a ledger hash) travels the same getter path as the 4-byte +/// scalars: every byte lands where the guest asked, and the status is the length. +#[test] +fn parent_ldgr_hash_writes_all_32_bytes_where_the_guest_asked() { + let host = FakeHost::new(); + + let wat = module( + &[import::PARENT_LDGR_HASH, ONE_PAGE], + "(call $parent_ldgr_hash (i32.const 64) (i32.const 32))", + ); + assert_eq!(status(&wat, &host), 32, "the byte count"); + + // The default hash is 0, 1, 2, ..., so its first four bytes load as 0x03020100. + let wat = module( + &[import::PARENT_LDGR_HASH, ONE_PAGE], + "(drop (call $parent_ldgr_hash (i32.const 64) (i32.const 32))) + (i32.load (i32.const 64))", + ); + assert_eq!( + status(&wat, &host), + 0x03020100, + "the first four bytes the host wrote" + ); +} + /// The output region is wherever the guest points, not a fixed address. #[test] fn the_output_region_is_the_pointer_the_guest_gave() { diff --git a/crates/xrpl-wasm-vm/tests/preflight.rs b/crates/xrpl-wasm-vm/tests/preflight.rs index 99b115ee29..c097c0a3bc 100644 --- a/crates/xrpl-wasm-vm/tests/preflight.rs +++ b/crates/xrpl-wasm-vm/tests/preflight.rs @@ -98,9 +98,10 @@ fn a_disabled_feature_does_not_pass() { /// Every host function the ABI declares, spelled as a guest imports it. The count /// is asserted against the ABI so a function added to it cannot be left out here. -const ALL_IMPORTS: [&str; 6] = [ +const ALL_IMPORTS: [&str; 7] = [ import::LDGR_INDEX, import::PARENT_LDGR_TIME, + import::PARENT_LDGR_HASH, import::HOME_LE_FIELD, import::SHA512_HALF, import::TRACE, diff --git a/crates/xrpl-wasm-vm/tests/support/mod.rs b/crates/xrpl-wasm-vm/tests/support/mod.rs index 8f280596fe..3d063b61b1 100644 --- a/crates/xrpl-wasm-vm/tests/support/mod.rs +++ b/crates/xrpl-wasm-vm/tests/support/mod.rs @@ -105,6 +105,8 @@ pub struct FakeHost { pub ledger_sqn: Answer, /// What `get_parent_ledger_time` answers. pub parent_ledger_time: Answer, + /// What `get_parent_ledger_hash` answers. + pub parent_ledger_hash: Answer, /// What `get_current_ledger_obj_field` answers, by field selector. An /// unlisted selector answers `FieldNotFound`. pub fields: HashMap, @@ -126,6 +128,8 @@ impl Default for FakeHost { // A distinct value from the sequence number, so a test cannot pass by // reading one where it meant the other. parent_ledger_time: Answer::bytes(9u32.to_le_bytes()), + // 32 bytes counting up from 0, the length of a real ledger hash. + parent_ledger_hash: Answer::filler(32), fields: HashMap::new(), digest: Answer::filler(32), fields_asked: RefCell::new(Vec::new()), @@ -150,6 +154,11 @@ impl FakeHost { self } + pub fn answering_parent_ledger_hash(mut self, answer: Answer) -> FakeHost { + self.parent_ledger_hash = answer; + self + } + pub fn answering_field(mut self, field: i32, answer: Answer) -> FakeHost { self.fields.insert(field, answer); self @@ -174,6 +183,10 @@ impl HostFunctions for FakeHost { self.parent_ledger_time.fill(out) } + fn get_parent_ledger_hash(&self, out: &mut [u8]) -> HostResult { + self.parent_ledger_hash.fill(out) + } + fn get_current_ledger_obj_field(&self, field: i32, out: &mut [u8]) -> HostResult { self.fields_asked.borrow_mut().push(field); match self.fields.get(&field) { @@ -216,6 +229,7 @@ pub mod import { pub const LDGR_INDEX: &str = r#"(import "host_lib" "ldgr_index" (func $ldgr_index (param i32 i32) (result i32)))"#; pub const PARENT_LDGR_TIME: &str = r#"(import "host_lib" "parent_ldgr_time" (func $parent_ldgr_time (param i32 i32) (result i32)))"#; + pub const PARENT_LDGR_HASH: &str = r#"(import "host_lib" "parent_ldgr_hash" (func $parent_ldgr_hash (param i32 i32) (result i32)))"#; pub const HOME_LE_FIELD: &str = r#"(import "host_lib" "home_le_field" (func $home_le_field (param i32 i32 i32) (result i32)))"#; pub const SHA512_HALF: &str = r#"(import "host_lib" "sha512_half" (func $sha512_half (param i32 i32 i32 i32) (result i32)))"#; pub const TRACE: &str = diff --git a/include/xrpl/tx/wasm/HostContext.h b/include/xrpl/tx/wasm/HostContext.h index cebeb52e0c..ca287762e5 100644 --- a/include/xrpl/tx/wasm/HostContext.h +++ b/include/xrpl/tx/wasm/HostContext.h @@ -47,6 +47,9 @@ public: [[nodiscard]] std::int32_t getParentLedgerTime(rust::Slice out) const noexcept; + [[nodiscard]] std::int32_t + getParentLedgerHash(rust::Slice out) const noexcept; + [[nodiscard]] std::int32_t getCurrentLedgerObjField(std::int32_t field, rust::Slice out) const noexcept; diff --git a/src/libxrpl/tx/wasm/HostContext.cpp b/src/libxrpl/tx/wasm/HostContext.cpp index 60dcb7ba2f..9bdac61f35 100644 --- a/src/libxrpl/tx/wasm/HostContext.cpp +++ b/src/libxrpl/tx/wasm/HostContext.cpp @@ -83,6 +83,18 @@ HostContext::getParentLedgerTime(rust::Slice out) const noexcept }); } +std::int32_t +HostContext::getParentLedgerHash(rust::Slice out) const noexcept +{ + return guarded(hostFunctions_.getJournal(), kHostInternal, [&] { + auto const hash = hostFunctions_.getParentLedgerHash(); + if (!hash) + return hfErrorToInt(hash.error()); + + return answer(out, hash->data(), hash->size()); + }); +} + std::int32_t HostContext::getCurrentLedgerObjField(std::int32_t field, rust::Slice out) const noexcept