Add Close instrruction and tooling to upgradeable loader (#15887)

sdk/program/src/bpf_loader_upgradeable.rs

@@ -227,6 +227,20 @@ pub fn set_upgrade_authority(
     Instruction::new_with_bincode(id(), &UpgradeableLoaderInstruction::SetAuthority, metas)
 }
 
+/// Returns the instructions required to close an account
+pub fn close(
+    close_address: &Pubkey,
+    recipient_address: &Pubkey,
+    authority_address: &Pubkey,
+) -> Instruction {
+    let metas = vec![
+        AccountMeta::new(*close_address, false),
+        AccountMeta::new(*recipient_address, false),
+        AccountMeta::new_readonly(*authority_address, true),
+    ];
+    Instruction::new_with_bincode(id(), &UpgradeableLoaderInstruction::Close, metas)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

sdk/program/src/loader_upgradeable_instruction.rs

@@ -107,4 +107,13 @@ pub enum UpgradeableLoaderInstruction {
     ///   2. `[]` The new authority, optional, if omitted then the program will
     ///      not be upgradeable.
     SetAuthority,
+
+    /// Closes an account owned by the upgradeable loader of all lamports and
+    /// withdraws all the lamports
+    ///
+    /// # Account references
+    ///   0. `[writable]` The account to close.
+    ///   1. `[writable]` The account to deposit the closed account's lamports.
+    ///   2. `[signer]` The account's authority.
+    Close,
 }

sdk/src/feature_set.rs

@@ -119,6 +119,10 @@ pub mod cpi_data_cost {
     solana_sdk::declare_id!("Hrg5bXePPGiAVWZfDHbvjqytSeyBDPAGAQ7v6N5i4gCX");
 }
 
+pub mod upgradeable_close_instruction {
+    solana_sdk::declare_id!("FsPaByos3gA9bUEhp3EimQpQPCoSvCEigHod496NmABQ");
+}
+
 lazy_static! {
     /// Map of feature identifiers to user-visible description
     pub static ref FEATURE_NAMES: HashMap<Pubkey, &'static str> = [
@@ -149,6 +153,7 @@ lazy_static! {
         (skip_ro_deserialization::id(), "skip deserialization of read-only accounts"),
         (require_stake_for_gossip::id(), "require stakes for propagating crds values through gossip #15561"),
         (cpi_data_cost::id(), "charge the compute budget for data passed via CPI"),
+        (upgradeable_close_instruction::id(), "close upgradeable buffer accounts"),
         /*************** ADD NEW FEATURES HERE ***************/
     ]
     .iter()