Add slot_history for slashing (solana-labs#7589)

* Add slot_history for slashing

* fixup

* fixup

programs/vote/src/vote_instruction.rs

@@ -227,9 +227,9 @@ mod tests {
             .iter()
             .map(|meta| {
                 if sysvar::clock::check_id(&meta.pubkey) {
-                    sysvar::clock::Clock::default().create_account(1)
+                    Clock::default().create_account(1)
                 } else if sysvar::slot_hashes::check_id(&meta.pubkey) {
-                    sysvar::slot_hashes::create_account(1, &[])
+                    SlotHashes::default().create_account(1)
                 } else if sysvar::rent::check_id(&meta.pubkey) {
                     Rent::free().create_account(1)
                 } else {

runtime/src/bank.rs

@@ -40,6 +40,7 @@ use solana_sdk::{
     pubkey::Pubkey,
     signature::{Keypair, Signature},
     slot_hashes::SlotHashes,
+    slot_history::SlotHistory,
     system_transaction,
     sysvar::{self, Sysvar},
     timing::years_as_slots,
@@ -516,16 +517,26 @@ impl Bank {
         );
     }
 
+    fn update_slot_history(&self) {
+        let mut slot_history = self
+            .get_account(&sysvar::slot_history::id())
+            .map(|account| SlotHistory::from_account(&account).unwrap())
+            .unwrap_or_default();
+
+        slot_history.add(self.slot());
+
+        self.store_account(&sysvar::slot_history::id(), &slot_history.create_account(1));
+    }
+
     fn update_slot_hashes(&self) {
-        let mut account = self
+        let mut slot_hashes = self
             .get_account(&sysvar::slot_hashes::id())
-            .unwrap_or_else(|| sysvar::slot_hashes::create_account(1, &[]));
+            .map(|account| SlotHashes::from_account(&account).unwrap())
+            .unwrap_or_default();
 
-        let mut slot_hashes = SlotHashes::from_account(&account).unwrap();
         slot_hashes.add(self.slot(), self.hash());
-        slot_hashes.to_account(&mut account).unwrap();
 
-        self.store_account(&sysvar::slot_hashes::id(), &account);
+        self.store_account(&sysvar::slot_hashes::id(), &slot_hashes.create_account(1));
     }
 
     fn update_fees(&self) {
@@ -650,6 +661,7 @@ impl Bank {
             // finish up any deferred changes to account state
             self.collect_fees();
             self.distribute_rent();
+            self.update_slot_history();
 
             // freeze is a one-way trip, idempotent
             *hash = self.hash_internal_state();

sdk/Cargo.toml

@@ -28,6 +28,7 @@ default = [
 assert_matches = { version = "1.3.0", optional = true }
 bincode = "1.2.1"
 bs58 = "0.3.0"
+bv = { version = "0.11.0", features = ["serde"] }
 byteorder = { version = "1.3.2", optional = true }
 generic-array = { version = "0.13.2", default-features = false, features = ["serde", "more_lengths"] }
 hex = "0.4.0"

sdk/benches/slot_hashes.rs

@@ -3,20 +3,18 @@
 extern crate test;
 use solana_sdk::{
     hash::Hash,
-    slot_hashes::{Slot, SlotHashes, MAX_SLOT_HASHES},
+    slot_hashes::{Slot, SlotHashes, MAX_ENTRIES},
     sysvar::Sysvar,
 };
 use test::Bencher;
 
 #[bench]
 fn bench_to_from_account(b: &mut Bencher) {
     let mut slot_hashes = SlotHashes::new(&[]);
-    for i in 0..MAX_SLOT_HASHES {
+    for i in 0..MAX_ENTRIES {
         slot_hashes.add(i as Slot, Hash::default());
     }
-    let mut reps = 0;
     b.iter(|| {
-        reps += 1;
         let account = slot_hashes.create_account(0);
         slot_hashes = SlotHashes::from_account(&account).unwrap();
     });

sdk/benches/slot_history.rs

@@ -0,0 +1,15 @@
+#![feature(test)]
+
+extern crate test;
+use solana_sdk::{slot_history::SlotHistory, sysvar::Sysvar};
+use test::Bencher;
+
+#[bench]
+fn bench_to_from_account(b: &mut Bencher) {
+    let mut slot_history = SlotHistory::default();
+
+    b.iter(|| {
+        let account = slot_history.create_account(0);
+        slot_history = SlotHistory::from_account(&account).unwrap();
+    });
+}

sdk/src/lib.rs

@@ -26,6 +26,7 @@ pub mod rent;
 pub mod rpc_port;
 pub mod short_vec;
 pub mod slot_hashes;
+pub mod slot_history;
 pub mod system_instruction;
 pub mod system_program;
 pub mod sysvar;

sdk/src/slot_hashes.rs

@@ -5,7 +5,7 @@
 use crate::hash::Hash;
 use std::{iter::FromIterator, ops::Deref};
 
-pub const MAX_SLOT_HASHES: usize = 512; // about 2.5 minutes to get your vote in
+pub const MAX_ENTRIES: usize = 512; // about 2.5 minutes to get your vote in
 
 pub use crate::clock::Slot;
 
@@ -21,7 +21,7 @@ impl SlotHashes {
             Ok(index) => (self.0)[index] = (slot, hash),
             Err(index) => (self.0).insert(index, (slot, hash)),
         }
-        (self.0).truncate(MAX_SLOT_HASHES);
+        (self.0).truncate(MAX_ENTRIES);
     }
     #[allow(clippy::trivially_copy_pass_by_ref)]
     pub fn get(&self, slot: &Slot) -> Option<&Hash> {
@@ -68,16 +68,16 @@ mod tests {
         );
 
         let mut slot_hashes = SlotHashes::new(&[]);
-        for i in 0..MAX_SLOT_HASHES + 1 {
+        for i in 0..MAX_ENTRIES + 1 {
             slot_hashes.add(
                 i as u64,
                 hash(&[(i >> 24) as u8, (i >> 16) as u8, (i >> 8) as u8, i as u8]),
             );
         }
-        for i in 0..MAX_SLOT_HASHES {
-            assert_eq!(slot_hashes[i].0, (MAX_SLOT_HASHES - i) as u64);
+        for i in 0..MAX_ENTRIES {
+            assert_eq!(slot_hashes[i].0, (MAX_ENTRIES - i) as u64);
         }
 
-        assert_eq!(slot_hashes.len(), MAX_SLOT_HASHES);
+        assert_eq!(slot_hashes.len(), MAX_ENTRIES);
     }
 }

sdk/src/slot_history.rs

@@ -0,0 +1,72 @@
+//!
+//! slot history
+//!
+pub use crate::clock::Slot;
+use bv::BitVec;
+
+#[repr(C)]
+#[derive(Serialize, Deserialize, PartialEq, Debug)]
+pub struct SlotHistory {
+    pub bits: BitVec<u64>,
+    pub next_slot: Slot,
+}
+
+impl Default for SlotHistory {
+    fn default() -> Self {
+        let mut bits = BitVec::new_fill(false, MAX_ENTRIES);
+        bits.set(0, true);
+        Self { bits, next_slot: 1 }
+    }
+}
+
+pub const MAX_ENTRIES: u64 = 1024 * 1024; // 1 million slots is about 5 days
+
+#[derive(PartialEq, Debug)]
+pub enum Check {
+    Future,
+    TooOld,
+    Found,
+    NotFound,
+}
+
+impl SlotHistory {
+    pub fn add(&mut self, slot: Slot) {
+        for skipped in self.next_slot..slot {
+            self.bits.set(skipped % MAX_ENTRIES, false);
+        }
+        self.bits.set(slot % MAX_ENTRIES, true);
+        self.next_slot = slot + 1;
+    }
+
+    pub fn check(&self, slot: Slot) -> Check {
+        if slot >= self.next_slot {
+            Check::Future
+        } else if self.next_slot - slot > MAX_ENTRIES {
+            Check::TooOld
+        } else if self.bits.get(slot % MAX_ENTRIES) {
+            Check::Found
+        } else {
+            Check::NotFound
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test() {
+        let mut slot_history = SlotHistory::default();
+        slot_history.add(2);
+        assert_eq!(slot_history.check(0), Check::Found);
+        assert_eq!(slot_history.check(1), Check::NotFound);
+        for i in 3..MAX_ENTRIES {
+            assert_eq!(slot_history.check(i), Check::Future);
+        }
+        slot_history.add(MAX_ENTRIES);
+        assert_eq!(slot_history.check(0), Check::TooOld);
+        assert_eq!(slot_history.check(1), Check::NotFound);
+        assert_eq!(slot_history.check(2), Check::Found);
+    }
+}

sdk/src/sysvar/mod.rs

@@ -14,6 +14,7 @@ pub mod recent_blockhashes;
 pub mod rent;
 pub mod rewards;
 pub mod slot_hashes;
+pub mod slot_history;
 pub mod stake_history;
 
 pub fn is_sysvar_id(id: &Pubkey) -> bool {
@@ -24,6 +25,7 @@ pub fn is_sysvar_id(id: &Pubkey) -> bool {
         || rent::check_id(id)
         || rewards::check_id(id)
         || slot_hashes::check_id(id)
+        || slot_history::check_id(id)
         || stake_history::check_id(id)
 }
 
@@ -59,11 +61,8 @@ pub trait SysvarId {
 pub trait Sysvar:
     SysvarId + Default + Sized + serde::Serialize + serde::de::DeserializeOwned
 {
-    fn biggest() -> Self {
-        Self::default()
-    }
     fn size_of() -> usize {
-        bincode::serialized_size(&Self::biggest()).unwrap() as usize
+        bincode::serialized_size(&Self::default()).unwrap() as usize
     }
     fn from_account(account: &Account) -> Option<Self> {
         bincode::deserialize(&account.data).ok()
@@ -84,7 +83,8 @@ pub trait Sysvar:
         Self::from_account(account.account).ok_or(InstructionError::InvalidArgument)
     }
     fn create_account(&self, lamports: u64) -> Account {
-        let mut account = Account::new(lamports, Self::size_of(), &id());
+        let data_len = Self::size_of().max(bincode::serialized_size(self).unwrap() as usize);
+        let mut account = Account::new(lamports, data_len, &id());
         self.to_account(&mut account).unwrap();
         account
     }

sdk/src/sysvar/recent_blockhashes.rs

@@ -39,8 +39,9 @@ impl<'a> FromIterator<&'a Hash> for RecentBlockhashes {
 }
 
 impl Sysvar for RecentBlockhashes {
-    fn biggest() -> Self {
-        RecentBlockhashes(vec![Hash::default(); MAX_ENTRIES])
+    fn size_of() -> usize {
+        // hard-coded so that we don't have to construct an empty
+        1032 // golden, update if MAX_ENTRIES changes
     }
 }
 
@@ -86,6 +87,15 @@ mod tests {
     use super::*;
     use crate::hash::Hash;
 
+    #[test]
+    fn test_size_of() {
+        assert_eq!(
+            bincode::serialized_size(&RecentBlockhashes(vec![Hash::default(); MAX_ENTRIES]))
+                .unwrap() as usize,
+            RecentBlockhashes::size_of()
+        );
+    }
+
     #[test]
     fn test_create_account_empty() {
         let account = create_account_with_data(42, vec![].into_iter());

sdk/src/sysvar/slot_hashes.rs

@@ -2,32 +2,42 @@
 //!
 //! this account carries the Bank's most recent blockhashes for some N parents
 //!
-pub use crate::slot_hashes::{Slot, SlotHash, SlotHashes, MAX_SLOT_HASHES};
-use crate::{account::Account, hash::Hash, sysvar::Sysvar};
+pub use crate::slot_hashes::SlotHashes;
+
+use crate::sysvar::Sysvar;
 
 crate::declare_sysvar_id!("SysvarS1otHashes111111111111111111111111111", SlotHashes);
 
 impl Sysvar for SlotHashes {
-    fn biggest() -> Self {
-        // override
-        (0..MAX_SLOT_HASHES)
-            .map(|slot| (slot as Slot, Hash::default()))
-            .collect::<Self>()
+    // override
+    fn size_of() -> usize {
+        // hard-coded so that we don't have to construct an empty
+        20_488 // golden, update if MAX_ENTRIES changes
     }
 }
 
-pub fn create_account(lamports: u64, slot_hashes: &[SlotHash]) -> Account {
-    SlotHashes::new(slot_hashes).create_account(lamports)
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::{clock::Slot, hash::Hash, slot_hashes::MAX_ENTRIES};
+
+    #[test]
+    fn test_size_of() {
+        assert_eq!(
+            SlotHashes::size_of(),
+            bincode::serialized_size(
+                &(0..MAX_ENTRIES)
+                    .map(|slot| (slot as Slot, Hash::default()))
+                    .collect::<SlotHashes>()
+            )
+            .unwrap() as usize
+        );
+    }
 
     #[test]
     fn test_create_account() {
         let lamports = 42;
-        let account = create_account(lamports, &[]);
+        let account = SlotHashes::new(&[]).create_account(lamports);
         assert_eq!(account.data.len(), SlotHashes::size_of());
         let slot_hashes = SlotHashes::from_account(&account);
         assert_eq!(slot_hashes, Some(SlotHashes::default()));

sdk/src/sysvar/slot_history.rs

@@ -0,0 +1,30 @@
+//! named accounts for synthesized data accounts for bank state, etc.
+//!
+//! this account carries a bitvector of slots present over the past
+//!   epoch
+//!
+pub use crate::slot_history::SlotHistory;
+
+use crate::sysvar::Sysvar;
+
+crate::declare_sysvar_id!("SysvarS1otHistory11111111111111111111111111", SlotHistory);
+
+impl Sysvar for SlotHistory {
+    // override
+    fn size_of() -> usize {
+        // hard-coded so that we don't have to construct an empty
+        131_097 // golden, update if MAX_ENTRIES changes
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn test_size_of() {
+        assert_eq!(
+            SlotHistory::size_of(),
+            bincode::serialized_size(&SlotHistory::default()).unwrap() as usize
+        );
+    }
+}