Actual no_std support

.github/workflows/build.yml

@@ -16,7 +16,7 @@ jobs:
                      1.41.0,
                      # 1.45.2 is MSRV for lightning-net-tokio, lightning-block-sync, and coverage generation
                      1.45.2,
-                     # 1.47.0 will be the MSRV for no_std builds using hashbrown once core2 is updated
+                     # 1.47.0 will be the MSRV for no-std builds using hashbrown once core2 is updated
                      1.47.0]
         include:
           - toolchain: stable
@@ -87,19 +87,19 @@ jobs:
       - name: Test on Rust ${{ matrix.toolchain }} with net-tokio and full code-linking for coverage generation
         if: matrix.coverage
         run: RUSTFLAGS="-C link-dead-code" cargo test --verbose --color always
-      - name: Test on no_std bullds Rust ${{ matrix.toolchain }}
+      - name: Test on no-std bullds Rust ${{ matrix.toolchain }}
         if: "matrix.build-no-std && !matrix.coverage"
         run: |
           cd lightning
-          cargo test --verbose --color always --no-default-features --features no_std
-          # check if there is a conflict between no_std and the default std feature
-          cargo test --verbose --color always --features no_std
+          cargo test --verbose --color always --no-default-features --features no-std
+          # check if there is a conflict between no-std and the default std feature
+          cargo test --verbose --color always --features no-std
           cd ..
-      - name: Test on no_std bullds Rust ${{ matrix.toolchain }} and full code-linking for coverage generation
+      - name: Test on no-std builds Rust ${{ matrix.toolchain }} and full code-linking for coverage generation
         if: "matrix.build-no-std && matrix.coverage"
         run: |
           cd lightning
-          RUSTFLAGS="-C link-dead-code" cargo test --verbose --color always --no-default-features --features no_std
+          RUSTFLAGS="-C link-dead-code" cargo test --verbose --color always --no-default-features --features no-std
           cd ..
       - name: Test on Rust ${{ matrix.toolchain }}
         if: "! matrix.build-net-tokio"

ci/check-compiles.sh

@@ -6,4 +6,4 @@ cargo check
 cargo doc
 cargo doc --document-private-items
 cd fuzz && cargo check --features=stdin_fuzz
-cd ../lightning && cargo check --no-default-features --features=no_std
+cd ../lightning && cargo check --no-default-features --features=no-std

lightning/Cargo.toml

@@ -26,25 +26,32 @@ max_level_debug = []
 unsafe_revoked_tx_signing = []
 unstable = []
 
-no_std = ["hashbrown", "bitcoin/no-std"]
+no-std = ["hashbrown", "bitcoin/no-std", "core2/alloc"]
 std = ["bitcoin/std"]
 
 default = ["std"]
 
 [dependencies]
-bitcoin = "0.27"
+bitcoin = { version = "0.27", default-features = false, features = ["secp-recovery"] }
+# TODO remove this once rust-bitcoin PR #637 is released
+secp256k1 = { version = "0.20.2", default-features = false, features = ["alloc"] }
 
 hashbrown = { version = "0.11", optional = true }
 hex = { version = "0.3", optional = true }
 regex = { version = "0.1.80", optional = true }
 
+core2 = { version = "0.3.0", optional = true, default-features = false }
+
 [dev-dependencies]
 hex = "0.3"
 regex = "0.1.80"
+# TODO remove this once rust-bitcoin PR #637 is released
+secp256k1 = { version = "0.20.2", default-features = false, features = ["alloc"] }
 
 [dev-dependencies.bitcoin]
 version = "0.27"
-features = ["bitcoinconsensus"]
+default-features = false
+features = ["bitcoinconsensus", "secp-recovery"]
 
 [package.metadata.docs.rs]
 features = ["allow_wallclock_use"] # When https://github.com/rust-lang/rust/issues/43781 complies with our MSVR, we can add nice banners in the docs for the methods behind this feature-gate.

lightning/src/chain/channelmonitor.rs

@@ -53,7 +53,7 @@ use util::events::Event;
 
 use prelude::*;
 use core::{cmp, mem};
-use std::io::Error;
+use io::{self, Error};
 use core::ops::Deref;
 use sync::Mutex;
 
@@ -88,7 +88,7 @@ pub struct ChannelMonitorUpdate {
 pub const CLOSED_CHANNEL_UPDATE_ID: u64 = core::u64::MAX;
 
 impl Writeable for ChannelMonitorUpdate {
-	fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
+	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 		write_ver_prefix!(w, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
 		self.update_id.write(w)?;
 		(self.updates.len() as u64).write(w)?;
@@ -100,7 +100,7 @@ impl Writeable for ChannelMonitorUpdate {
 	}
 }
 impl Readable for ChannelMonitorUpdate {
-	fn read<R: ::std::io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+	fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
 		let _ver = read_ver_prefix!(r, SERIALIZATION_VERSION);
 		let update_id: u64 = Readable::read(r)?;
 		let len: u64 = Readable::read(r)?;
@@ -293,7 +293,7 @@ struct CounterpartyCommitmentTransaction {
 }
 
 impl Writeable for CounterpartyCommitmentTransaction {
-	fn write<W: Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {
+	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 		w.write_all(&byte_utils::be64_to_array(self.per_htlc.len() as u64))?;
 		for (ref txid, ref htlcs) in self.per_htlc.iter() {
 			w.write_all(&txid[..])?;
@@ -311,7 +311,7 @@ impl Writeable for CounterpartyCommitmentTransaction {
 	}
 }
 impl Readable for CounterpartyCommitmentTransaction {
-	fn read<R: ::std::io::Read>(r: &mut R) -> Result<Self, DecodeError> {
+	fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
 		let counterparty_commitment_transaction = {
 			let per_htlc_len: u64 = Readable::read(r)?;
 			let mut per_htlc = HashMap::with_capacity(cmp::min(per_htlc_len as usize, MAX_ALLOC_SIZE / 64));
@@ -2581,7 +2581,7 @@ const MAX_ALLOC_SIZE: usize = 64*1024;
 
 impl<'a, Signer: Sign, K: KeysInterface<Signer = Signer>> ReadableArgs<&'a K>
 		for (BlockHash, ChannelMonitor<Signer>) {
-	fn read<R: ::std::io::Read>(reader: &mut R, keys_manager: &'a K) -> Result<Self, DecodeError> {
+	fn read<R: io::Read>(reader: &mut R, keys_manager: &'a K) -> Result<Self, DecodeError> {
 		macro_rules! unwrap_obj {
 			($key: expr) => {
 				match $key {

lightning/src/chain/keysinterface.rs

@@ -39,7 +39,7 @@ use ln::msgs::UnsignedChannelAnnouncement;
 
 use prelude::*;
 use core::sync::atomic::{AtomicUsize, Ordering};
-use std::io::Error;
+use io::{self, Error};
 use ln::msgs::{DecodeError, MAX_VALUE_MSAT};
 
 /// Information about a spendable output to a P2WSH script. See
@@ -699,7 +699,7 @@ impl Writeable for InMemorySigner {
 }
 
 impl Readable for InMemorySigner {
-	fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+	fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 		let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
 
 		let funding_key = Readable::read(reader)?;
@@ -1039,7 +1039,7 @@ impl KeysInterface for KeysManager {
 	}
 
 	fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
-		InMemorySigner::read(&mut std::io::Cursor::new(reader))
+		InMemorySigner::read(&mut io::Cursor::new(reader))
 	}
 
 	fn sign_invoice(&self, invoice_preimage: Vec<u8>) -> Result<RecoverableSignature, ()> {

lightning/src/chain/onchaintx.rs

@@ -32,6 +32,7 @@ use util::logger::Logger;
 use util::ser::{Readable, ReadableArgs, Writer, Writeable, VecWriter};
 use util::byte_utils;
 
+use io;
 use prelude::*;
 use alloc::collections::BTreeMap;
 use core::cmp;
@@ -94,7 +95,7 @@ impl_writeable_tlv_based_enum!(OnchainEvent,
 ;);
 
 impl Readable for Option<Vec<Option<(usize, Signature)>>> {
-	fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+	fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 		match Readable::read(reader)? {
 			0u8 => Ok(None),
 			1u8 => {
@@ -115,7 +116,7 @@ impl Readable for Option<Vec<Option<(usize, Signature)>>> {
 }
 
 impl Writeable for Option<Vec<Option<(usize, Signature)>>> {
-	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 		match self {
 			&Some(ref vec) => {
 				1u8.write(writer)?;
@@ -191,7 +192,7 @@ const SERIALIZATION_VERSION: u8 = 1;
 const MIN_SERIALIZATION_VERSION: u8 = 1;
 
 impl<ChannelSigner: Sign> OnchainTxHandler<ChannelSigner> {
-	pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+	pub(crate) fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 		write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
 
 		self.destination_script.write(writer)?;
@@ -242,7 +243,7 @@ impl<ChannelSigner: Sign> OnchainTxHandler<ChannelSigner> {
 }
 
 impl<'a, K: KeysInterface> ReadableArgs<&'a K> for OnchainTxHandler<K::Signer> {
-	fn read<R: ::std::io::Read>(reader: &mut R, keys_manager: &'a K) -> Result<Self, DecodeError> {
+	fn read<R: io::Read>(reader: &mut R, keys_manager: &'a K) -> Result<Self, DecodeError> {
 		let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
 
 		let destination_script = Readable::read(reader)?;
@@ -285,7 +286,7 @@ impl<'a, K: KeysInterface> ReadableArgs<&'a K> for OnchainTxHandler<K::Signer> {
 		for _ in 0..locktimed_packages_len {
 			let locktime = Readable::read(reader)?;
 			let packages_len: u64 = Readable::read(reader)?;
-			let mut packages = Vec::with_capacity(cmp::min(packages_len as usize, MAX_ALLOC_SIZE / std::mem::size_of::<PackageTemplate>()));
+			let mut packages = Vec::with_capacity(cmp::min(packages_len as usize, MAX_ALLOC_SIZE / core::mem::size_of::<PackageTemplate>()));
 			for _ in 0..packages_len {
 				packages.push(Readable::read(reader)?);
 			}

lightning/src/chain/package.rs

@@ -31,6 +31,8 @@ use util::byte_utils;
 use util::logger::Logger;
 use util::ser::{Readable, Writer, Writeable};
 
+use io;
+use prelude::*;
 use core::cmp;
 use core::mem;
 use core::ops::Deref;
@@ -395,8 +397,8 @@ impl PackageSolvingData {
 			PackageSolvingData::RevokedOutput(_) => output_conf_height + 1,
 			PackageSolvingData::RevokedHTLCOutput(_) => output_conf_height + 1,
 			PackageSolvingData::CounterpartyOfferedHTLCOutput(_) => output_conf_height + 1,
-			PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => std::cmp::max(outp.htlc.cltv_expiry, output_conf_height + 1),
-			PackageSolvingData::HolderHTLCOutput(ref outp) => std::cmp::max(outp.cltv_expiry, output_conf_height + 1),
+			PackageSolvingData::CounterpartyReceivedHTLCOutput(ref outp) => cmp::max(outp.htlc.cltv_expiry, output_conf_height + 1),
+			PackageSolvingData::HolderHTLCOutput(ref outp) => cmp::max(outp.cltv_expiry, output_conf_height + 1),
 			PackageSolvingData::HolderFundingOutput(_) => output_conf_height + 1,
 		};
 		absolute_timelock
@@ -682,7 +684,7 @@ impl PackageTemplate {
 }
 
 impl Writeable for PackageTemplate {
-	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 		writer.write_all(&byte_utils::be64_to_array(self.inputs.len() as u64))?;
 		for (ref outpoint, ref rev_outp) in self.inputs.iter() {
 			outpoint.write(writer)?;
@@ -699,7 +701,7 @@ impl Writeable for PackageTemplate {
 }
 
 impl Readable for PackageTemplate {
-	fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+	fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 		let inputs_count = <u64 as Readable>::read(reader)?;
 		let mut inputs: Vec<(BitcoinOutPoint, PackageSolvingData)> = Vec::with_capacity(cmp::min(inputs_count as usize, MAX_ALLOC_SIZE / 128));
 		for _ in 0..inputs_count {

lightning/src/lib.rs

@@ -28,31 +28,119 @@
 #![allow(bare_trait_objects)]
 #![allow(ellipsis_inclusive_range_patterns)]
 
+#![cfg_attr(all(not(feature = "std"), not(test)), no_std)]
+
 #![cfg_attr(all(any(test, feature = "_test_utils"), feature = "unstable"), feature(test))]
 #[cfg(all(any(test, feature = "_test_utils"), feature = "unstable"))] extern crate test;
 
+#[cfg(not(any(feature = "std", feature = "no-std")))]
+compile_error!("at least one of the `std` or `no-std` features must be enabled");
+
 #[macro_use]
 extern crate alloc;
 extern crate bitcoin;
+#[cfg(any(test, feature = "std"))]
 extern crate core;
+
 #[cfg(any(test, feature = "_test_utils"))] extern crate hex;
 #[cfg(any(test, feature = "fuzztarget", feature = "_test_utils"))] extern crate regex;
 
+#[cfg(not(feature = "std"))] extern crate core2;
+
 #[macro_use]
 pub mod util;
 pub mod chain;
 pub mod ln;
 pub mod routing;
 
+#[cfg(feature = "std")]
+use std::io;
+#[cfg(not(feature = "std"))]
+use core2::io;
+
+#[cfg(not(feature = "std"))]
+mod io_extras {
+	use core2::io::{self, Read, Write};
+
+	/// A writer which will move data into the void.
+	pub struct Sink {
+		_priv: (),
+	}
+
+	/// Creates an instance of a writer which will successfully consume all data.
+	pub const fn sink() -> Sink {
+		Sink { _priv: () }
+	}
+
+	impl core2::io::Write for Sink {
+		#[inline]
+		fn write(&mut self, buf: &[u8]) -> core2::io::Result<usize> {
+			Ok(buf.len())
+		}
+
+		#[inline]
+		fn flush(&mut self) -> core2::io::Result<()> {
+			Ok(())
+		}
+	}
+
+	pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> Result<u64, io::Error>
+		where
+		R: Read,
+		W: Write,
+	{
+		let mut count = 0;
+		let mut buf = [0u8; 64];
+
+		loop {
+			match reader.read(&mut buf) {
+				Ok(0) => break,
+				Ok(n) => { writer.write_all(&buf[0..n])?; count += n as u64; },
+				Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {},
+				Err(e) => return Err(e.into()),
+			};
+		}
+		Ok(count)
+	}
+
+	pub fn read_to_end<D: io::Read>(mut d: D) -> Result<alloc::vec::Vec<u8>, io::Error> {
+		let mut result = vec![];
+		let mut buf = [0u8; 64];
+		loop {
+			match d.read(&mut buf) {
+				Ok(0) => break,
+				Ok(n) => result.extend_from_slice(&buf[0..n]),
+				Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {},
+				Err(e) => return Err(e.into()),
+			};
+		}
+		Ok(result)
+	}
+}
+
+#[cfg(feature = "std")]
+mod io_extras {
+	pub fn read_to_end<D: ::std::io::Read>(mut d: D) -> Result<Vec<u8>, ::std::io::Error> {
+		let mut buf = Vec::new();
+		d.read_to_end(&mut buf)?;
+		Ok(buf)
+	}
+
+	pub use std::io::{copy, sink};
+}
+
 mod prelude {
 	#[cfg(feature = "hashbrown")]
 	extern crate hashbrown;
 
-	pub use alloc::{vec, vec::Vec, string::String, collections::VecDeque};
+	pub use alloc::{vec, vec::Vec, string::String, collections::VecDeque, boxed::Box};
 	#[cfg(not(feature = "hashbrown"))]
 	pub use std::collections::{HashMap, HashSet, hash_map};
 	#[cfg(feature = "hashbrown")]
 	pub use self::hashbrown::{HashMap, HashSet, hash_map};
+
+	pub use alloc::borrow::ToOwned;
+	pub use alloc::string::ToString;
 }
 
 #[cfg(feature = "std")]

lightning/src/ln/chan_utils.rs

@@ -31,6 +31,7 @@ use bitcoin::secp256k1::{Secp256k1, Signature, Message};
 use bitcoin::secp256k1::Error as SecpError;
 use bitcoin::secp256k1;
 
+use io;
 use prelude::*;
 use core::cmp;
 use ln::chan_utils;
@@ -167,7 +168,7 @@ impl CounterpartyCommitmentSecrets {
 }
 
 impl Writeable for CounterpartyCommitmentSecrets {
-	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 		for &(ref secret, ref idx) in self.old_secrets.iter() {
 			writer.write_all(secret)?;
 			writer.write_all(&byte_utils::be64_to_array(*idx))?;
@@ -177,7 +178,7 @@ impl Writeable for CounterpartyCommitmentSecrets {
 	}
 }
 impl Readable for CounterpartyCommitmentSecrets {
-	fn read<R: ::std::io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+	fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
 		let mut old_secrets = [([0; 32], 1 << 48); 49];
 		for &mut (ref mut secret, ref mut idx) in old_secrets.iter_mut() {
 			*secret = Readable::read(reader)?;