Bank: Add function to replace empty account with upgradeable program on feature activation

runtime/src/bank.rs

@@ -42,6 +42,7 @@ use {
         builtins::{BuiltinPrototype, BUILTINS},
         epoch_rewards_hasher::hash_rewards_into_partitions,
         epoch_stakes::{EpochStakes, NodeVoteAccounts},
+        inline_feature_gate_program,
         runtime_config::RuntimeConfig,
         serde_snapshot::BankIncrementalSnapshotPersistence,
         snapshot_hash::SnapshotHash,
@@ -215,6 +216,7 @@ pub mod bank_hash_details;
 mod builtin_programs;
 pub mod epoch_accounts_hash_utils;
 mod metrics;
+mod replace_account;
 mod serde_snapshot;
 mod sysvar_cache;
 #[cfg(test)]
@@ -8054,6 +8056,24 @@ impl Bank {
         if new_feature_activations.contains(&feature_set::update_hashes_per_tick::id()) {
             self.apply_updated_hashes_per_tick(DEFAULT_HASHES_PER_TICK);
         }
+
+        if new_feature_activations.contains(&feature_set::programify_feature_gate_program::id()) {
+            let datapoint_name = "bank-progamify_feature_gate_program";
+            if let Err(e) = replace_account::replace_empty_account_with_upgradeable_program(
+                self,
+                &feature::id(),
+                &inline_feature_gate_program::noop_program::id(),
+                datapoint_name,
+            ) {
+                warn!(
+                    "{}: Failed to replace empty account {} with upgradeable program: {}",
+                    datapoint_name,
+                    feature::id(),
+                    e
+                );
+                datapoint_warn!(datapoint_name, ("slot", self.slot(), i64),);
+            }
+        }
     }
 
     fn apply_updated_hashes_per_tick(&mut self, hashes_per_tick: u64) {
@@ -8196,42 +8216,6 @@ impl Bank {
         }
     }
 
-    /// Use to replace programs by feature activation
-    #[allow(dead_code)]
-    fn replace_program_account(
-        &mut self,
-        old_address: &Pubkey,
-        new_address: &Pubkey,
-        datapoint_name: &'static str,
-    ) {
-        if let Some(old_account) = self.get_account_with_fixed_root(old_address) {
-            if let Some(new_account) = self.get_account_with_fixed_root(new_address) {
-                datapoint_info!(datapoint_name, ("slot", self.slot, i64));
-
-                // Burn lamports in the old account
-                self.capitalization
-                    .fetch_sub(old_account.lamports(), Relaxed);
-
-                // Transfer new account to old account
-                self.store_account(old_address, &new_account);
-
-                // Clear new account
-                self.store_account(new_address, &AccountSharedData::default());
-
-                // Unload a program from the bank's cache
-                self.loaded_programs_cache
-                    .write()
-                    .unwrap()
-                    .remove_programs([*old_address].into_iter());
-
-                self.calculate_and_update_accounts_data_size_delta_off_chain(
-                    old_account.data().len(),
-                    new_account.data().len(),
-                );
-            }
-        }
-    }
-
     /// Get all the accounts for this bank and calculate stats
     pub fn get_total_accounts_stats(&self) -> ScanResult<TotalAccountsStats> {
         let accounts = self.get_all_accounts()?;

runtime/src/bank/replace_account.rs

@@ -0,0 +1,191 @@
+use {
+    super::Bank,
+    log::*,
+    solana_accounts_db::accounts_index::ZeroLamport,
+    solana_sdk::{
+        account::{Account, AccountSharedData, ReadableAccount},
+        bpf_loader_upgradeable::{self, UpgradeableLoaderState},
+        pubkey::Pubkey,
+    },
+    std::sync::atomic::Ordering::Relaxed,
+    thiserror::Error,
+};
+
+/// Errors returned by `replace_account` methods
+#[derive(Debug, Error)]
+pub enum ReplaceAccountError {
+    /// Account not found
+    #[error("Account not found: {0:?}")]
+    AccountNotFound(Pubkey),
+    /// Account exists
+    #[error("Account exists: {0:?}")]
+    AccountExists(Pubkey),
+    #[error("Bincode Error: {0}")]
+    BincodeError(#[from] bincode::Error),
+    /// Not an upgradeable program
+    #[error("Not an upgradeable program")]
+    NotAnUpgradeableProgram,
+}
+
+/// Moves one account in place of another
+/// `source`: the account to replace with
+/// `destination`: the account to be replaced
+fn move_account<U, V>(
+    bank: &Bank,
+    source_address: &Pubkey,
+    source_account: &V,
+    destination_address: &Pubkey,
+    destination_account: Option<&U>,
+) where
+    U: ReadableAccount + Sync + ZeroLamport,
+    V: ReadableAccount + Sync + ZeroLamport,
+{
+    let (destination_lamports, destination_len) = match destination_account {
+        Some(destination_account) => (
+            destination_account.lamports(),
+            destination_account.data().len(),
+        ),
+        None => (0, 0),
+    };
+
+    // Burn lamports in the destination account
+    bank.capitalization.fetch_sub(destination_lamports, Relaxed);
+
+    // Transfer source account to destination account
+    bank.store_account(destination_address, source_account);
+
+    // Clear source account
+    bank.store_account(source_address, &AccountSharedData::default());
+
+    bank.calculate_and_update_accounts_data_size_delta_off_chain(
+        destination_len,
+        source_account.data().len(),
+    );
+}
+
+/// Use to replace non-upgradeable programs by feature activation
+/// `source`: the non-upgradeable program account to replace with
+/// `destination`: the non-upgradeable program account to be replaced
+#[allow(dead_code)]
+pub(crate) fn replace_non_upgradeable_program_account(
+    bank: &Bank,
+    source_address: &Pubkey,
+    destination_address: &Pubkey,
+    datapoint_name: &'static str,
+) -> Result<(), ReplaceAccountError> {
+    let destination_account = bank
+        .get_account_with_fixed_root(destination_address)
+        .ok_or(ReplaceAccountError::AccountNotFound(*destination_address))?;
+    let source_account = bank
+        .get_account_with_fixed_root(source_address)
+        .ok_or(ReplaceAccountError::AccountNotFound(*source_address))?;
+
+    datapoint_info!(datapoint_name, ("slot", bank.slot, i64));
+
+    move_account(
+        bank,
+        source_address,
+        &source_account,
+        destination_address,
+        Some(&destination_account),
+    );
+
+    // Unload a program from the bank's cache
+    bank.loaded_programs_cache
+        .write()
+        .unwrap()
+        .remove_programs([*destination_address].into_iter());
+
+    Ok(())
+}
+
+/// Use to replace an empty account with a program by feature activation
+/// Note: The upgradeable program should have both:
+///     - Program account
+///     - Program data account
+/// `source`: the upgradeable program account to replace with
+/// `destination`: the empty account to be replaced
+pub(crate) fn replace_empty_account_with_upgradeable_program(
+    bank: &Bank,
+    source_address: &Pubkey,
+    destination_address: &Pubkey,
+    datapoint_name: &'static str,
+) -> Result<(), ReplaceAccountError> {
+    // Must be attempting to replace an empty account with a program
+    // account _and_ data account
+    let source_account = bank
+        .get_account_with_fixed_root(source_address)
+        .ok_or(ReplaceAccountError::AccountNotFound(*source_address))?;
+
+    let (destination_data_address, _) = Pubkey::find_program_address(
+        &[destination_address.as_ref()],
+        &bpf_loader_upgradeable::id(),
+    );
+    let (source_data_address, _) =
+        Pubkey::find_program_address(&[source_address.as_ref()], &bpf_loader_upgradeable::id());
+
+    // Make sure the data within the source account is the PDA of its
+    // data account. This also means it has at least the necessary
+    // lamports for rent.
+    let source_state = bincode::deserialize::<UpgradeableLoaderState>(source_account.data())?;
+    if !matches!(source_state, UpgradeableLoaderState::Program { .. }) {
+        return Err(ReplaceAccountError::NotAnUpgradeableProgram);
+    }
+
+    let source_data_account = bank
+        .get_account_with_fixed_root(&source_data_address)
+        .ok_or(ReplaceAccountError::AccountNotFound(source_data_address))?;
+
+    // Make sure the destination account is empty
+    // We aren't going to check that there isn't a data account at
+    // the known program-derived address (ie. `destination_data_address`),
+    // because if it exists, it will be overwritten
+    if bank
+        .get_account_with_fixed_root(destination_address)
+        .is_some()
+    {
+        return Err(ReplaceAccountError::AccountExists(*destination_address));
+    }
+    let state = UpgradeableLoaderState::Program {
+        programdata_address: destination_data_address,
+    };
+    let data = bincode::serialize(&state)?;
+    let lamports = bank.get_minimum_balance_for_rent_exemption(data.len());
+    let created_program_account = Account {
+        lamports,
+        data,
+        owner: bpf_loader_upgradeable::id(),
+        executable: true,
+        rent_epoch: source_account.rent_epoch(),
+    };
+
+    datapoint_info!(datapoint_name, ("slot", bank.slot, i64));
+    let change_in_capitalization = source_account.lamports().saturating_sub(lamports);
+
+    // Replace the destination data account with the source one
+    // If the destination data account does not exist, it will be created
+    // If it does exist, it will be overwritten
+    move_account(
+        bank,
+        &source_data_address,
+        &source_data_account,
+        &destination_data_address,
+        bank.get_account_with_fixed_root(&destination_data_address)
+            .as_ref(),
+    );
+
+    // Write the source data account's PDA into the destination program account
+    move_account(
+        bank,
+        source_address,
+        &created_program_account,
+        destination_address,
+        None::<&AccountSharedData>,
+    );
+
+    // Any remaining lamports in the source program account are burnt
+    bank.capitalization
+        .fetch_sub(change_in_capitalization, Relaxed);
+
+    Ok(())
+}