Feat: SNS Realloc Name Account (solana-labs#3955)

* add new realloc ix

* add tests

* update param order to be consistent with other builders

* add realloc ix to instructions.ts

* ts bindings for realloc

* ts linting

* fix logs and clippy arithmetic

* satisfy clippy

* Update name-service/program/src/instruction.rs

Co-authored-by: Jon Cinque <joncinque@pm.me>

* Update name-service/program/src/instruction.rs

Co-authored-by: Jon Cinque <joncinque@pm.me>

* docs nits

* fix import ordering

* Update name-service/program/tests/functional.rs

Co-authored-by: Jon Cinque <joncinque@pm.me>

* blockhash nits

* Update name-service/js/src/bindings.ts

Co-authored-by: Jon Cinque <joncinque@pm.me>

* fix hashed_name naming

Co-authored-by: Jon Cinque <joncinque@pm.me>

name-service/js/src/bindings.ts

@@ -8,6 +8,7 @@ import {
 import {
   createInstruction,
   deleteInstruction,
+  reallocInstruction,
   transferInstruction,
   updateInstruction,
 } from './instructions';
@@ -217,3 +218,49 @@ export async function deleteNameRegistry(
 
   return changeAuthoritiesInstr;
 }
+
+/**
+ * Realloc the name account space.
+ *
+ * @param connection The solana connection object to the RPC node
+ * @param name The name of the name account
+ * @param space The new space to be allocated
+ * @param payerKey The allocation cost payer if new space is larger than current or the refund destination if smaller
+ * @param nameClass The class of this name, if it exsists
+ * @param nameParent The parent name of this name, if it exists
+ * @returns
+ */
+export async function reallocNameAccount(
+  connection: Connection,
+  name: string,
+  space: number,
+  payerKey: PublicKey,
+  nameClass?: PublicKey,
+  nameParent?: PublicKey
+): Promise<TransactionInstruction> {
+  const hashedName = await getHashedName(name);
+  const nameAccountKey = await getNameAccountKey(
+    hashedName,
+    nameClass,
+    nameParent
+  );
+
+  let nameOwner: PublicKey;
+  if (nameClass) {
+    nameOwner = nameClass;
+  } else {
+    nameOwner = (await NameRegistryState.retrieve(connection, nameAccountKey))
+      .owner;
+  }
+
+  const reallocInstr = reallocInstruction(
+    NAME_PROGRAM_ID,
+    SystemProgram.programId,
+    payerKey,
+    nameAccountKey,
+    nameOwner,
+    new Numberu32(space)
+  );
+
+  return reallocInstr;
+}

name-service/js/src/instructions.ts

@@ -214,3 +214,44 @@ export function deleteInstruction(
     data,
   });
 }
+
+export function reallocInstruction(
+  nameProgramId: PublicKey,
+  systemProgramId: PublicKey,
+  payerKey: PublicKey,
+  nameAccountKey: PublicKey,
+  nameOwnerKey: PublicKey,
+  space: Numberu32
+): TransactionInstruction {
+  const buffers = [Buffer.from(Int8Array.from([4])), space.toBuffer()];
+
+  const data = Buffer.concat(buffers);
+  const keys = [
+    {
+      pubkey: systemProgramId,
+      isSigner: false,
+      isWritable: false,
+    },
+    {
+      pubkey: payerKey,
+      isSigner: true,
+      isWritable: true,
+    },
+    {
+      pubkey: nameAccountKey,
+      isSigner: false,
+      isWritable: true,
+    },
+    {
+      pubkey: nameOwnerKey,
+      isSigner: true,
+      isWritable: false,
+    },
+  ];
+
+  return new TransactionInstruction({
+    keys,
+    programId: nameProgramId,
+    data,
+  });
+}

name-service/program/src/instruction.rs

@@ -89,6 +89,23 @@ pub enum NameRegistryInstruction {
     ///   2. `[writeable]` Refund account
     ///
     Delete,
+
+    /// Realloc the data of a name record.
+    ///
+    /// The space change cannot be more than `MAX_PERMITTED_DATA_LENGTH` greater than
+    /// current `space`.
+    ///
+    /// Accounts expected by this instruction:
+    ///   0. `[]` System program
+    ///   1. `[writeable, signer]` Payer account (will be refunded if new `space` is less than current `space`)
+    ///   2. `[writeable]` Name record to be reallocated
+    ///   3. `[signer]` Account owner
+    ///
+    Realloc {
+        /// New total number of bytes in addition to the `NameRecordHeader`.
+        /// There are no checks on the existing data; it will be truncated if the new space is less than the current space.
+        space: u32,
+    },
 }
 
 #[allow(clippy::too_many_arguments)]
@@ -201,3 +218,26 @@ pub fn delete(
         data,
     })
 }
+
+pub fn realloc(
+    name_service_program_id: Pubkey,
+    payer_key: Pubkey,
+    name_account_key: Pubkey,
+    name_owner_key: Pubkey,
+    space: u32,
+) -> Result<Instruction, ProgramError> {
+    let instruction_data = NameRegistryInstruction::Realloc { space };
+    let data = instruction_data.try_to_vec().unwrap();
+    let accounts = vec![
+        AccountMeta::new_readonly(system_program::id(), false),
+        AccountMeta::new(payer_key, true),
+        AccountMeta::new(name_account_key, false),
+        AccountMeta::new_readonly(name_owner_key, true),
+    ];
+
+    Ok(Instruction {
+        program_id: name_service_program_id,
+        accounts,
+        data,
+    })
+}

name-service/program/src/processor.rs

@@ -13,8 +13,11 @@ use {
         program_error::ProgramError,
         program_pack::Pack,
         pubkey::Pubkey,
+        rent::Rent,
         system_instruction,
+        sysvar::Sysvar,
     },
+    std::cmp::Ordering,
 };
 
 pub struct Processor {}
@@ -239,6 +242,57 @@ impl Processor {
         Ok(())
     }
 
+    fn process_realloc(accounts: &[AccountInfo], space: u32) -> ProgramResult {
+        let accounts_iter = &mut accounts.iter();
+        let system_program = next_account_info(accounts_iter)?;
+        let payer_account = next_account_info(accounts_iter)?;
+        let name_account = next_account_info(accounts_iter)?;
+        let name_owner = next_account_info(accounts_iter)?;
+
+        let name_record_header = NameRecordHeader::unpack_from_slice(&name_account.data.borrow())?;
+
+        // Verifications
+        if !name_owner.is_signer || name_record_header.owner != *name_owner.key {
+            msg!("The given name owner is incorrect or not a signer.");
+            return Err(ProgramError::InvalidArgument);
+        }
+
+        let new_space = NameRecordHeader::LEN.saturating_add(space as usize);
+        let required_lamports = Rent::get()?.minimum_balance(new_space);
+        match name_account.lamports().cmp(&required_lamports) {
+            Ordering::Less => {
+                // Overflow cannot happen here because we already checked the sizes.
+                #[allow(clippy::integer_arithmetic)]
+                let lamports_to_add = required_lamports - name_account.lamports();
+                invoke(
+                    &system_instruction::transfer(
+                        payer_account.key,
+                        name_account.key,
+                        lamports_to_add,
+                    ),
+                    &[
+                        payer_account.clone(),
+                        name_account.clone(),
+                        system_program.clone(),
+                    ],
+                )?;
+            }
+            Ordering::Greater => {
+                // Overflow cannot happen here because we already checked the sizes.
+                #[allow(clippy::integer_arithmetic)]
+                let lamports_to_remove = name_account.lamports() - required_lamports;
+                let source_amount: &mut u64 = &mut name_account.lamports.borrow_mut();
+                let dest_amount: &mut u64 = &mut payer_account.lamports.borrow_mut();
+                *source_amount = source_amount.saturating_sub(lamports_to_remove);
+                *dest_amount = dest_amount.saturating_add(lamports_to_remove);
+            }
+            Ordering::Equal => {}
+        }
+        // Max data increase is checked in realloc. No need to check here.
+        name_account.realloc(new_space, false)?;
+        Ok(())
+    }
+
     pub fn process_instruction(
         program_id: &Pubkey,
         accounts: &[AccountInfo],
@@ -270,6 +324,10 @@ impl Processor {
                 msg!("Instruction: Delete Name");
                 Processor::process_delete(accounts)?;
             }
+            NameRegistryInstruction::Realloc { space } => {
+                msg!("Instruction: Realloc Name Record");
+                Processor::process_realloc(accounts, space)?;
+            }
         }
         Ok(())
     }

name-service/program/tests/functional.rs

@@ -2,7 +2,9 @@
 use std::str::FromStr;
 
 use solana_program::{instruction::Instruction, program_pack::Pack, pubkey::Pubkey};
-use solana_program_test::{processor, tokio, ProgramTest, ProgramTestContext};
+use solana_program_test::{
+    processor, tokio, ProgramTest, ProgramTestBanksClientExt, ProgramTestContext,
+};
 
 use solana_program::hash::hashv;
 use solana_sdk::{
@@ -11,7 +13,7 @@ use solana_sdk::{
     transport::TransportError,
 };
 use spl_name_service::{
-    instruction::{create, delete, transfer, update, NameRegistryInstruction},
+    instruction::{create, delete, realloc, transfer, update, NameRegistryInstruction},
     processor::Processor,
     state::{get_seeds_and_key, NameRecordHeader, HASH_PREFIX},
 };
@@ -175,6 +177,59 @@ async fn test_name_service() {
     .unwrap();
     println!("Name Record Header: {:?}", name_record_header);
 
+    let data = "hello".as_bytes().to_vec();
+    let update_instruction = update(
+        program_id,
+        space as u32,
+        data,
+        name_account_key,
+        sol_subdomains_class.pubkey(),
+        Some(name_record_header.parent_name),
+    )
+    .unwrap();
+
+    sign_send_instruction(
+        &mut ctx,
+        update_instruction.clone(),
+        vec![&sol_subdomains_class],
+    )
+    .await
+    .unwrap_err();
+
+    let new_space = space.checked_mul(2).unwrap();
+    let payer_key = ctx.payer.pubkey();
+    let realloc_instruction = |space| {
+        realloc(
+            program_id,
+            payer_key,
+            name_account_key,
+            payer_key,
+            space as u32,
+        )
+        .unwrap()
+    };
+
+    sign_send_instruction(&mut ctx, realloc_instruction(new_space), vec![])
+        .await
+        .unwrap();
+
+    // update blockhash to prevent losing txn to dedup
+    ctx.last_blockhash = ctx
+        .banks_client
+        .get_new_latest_blockhash(&ctx.last_blockhash)
+        .await
+        .unwrap();
+
+    // resend update ix. Should succeed this time.
+    sign_send_instruction(&mut ctx, update_instruction, vec![&sol_subdomains_class])
+        .await
+        .unwrap();
+
+    // realloc to smaller this time
+    sign_send_instruction(&mut ctx, realloc_instruction(space / 2), vec![])
+        .await
+        .unwrap();
+
     let delete_instruction = delete(
         program_id,
         name_account_key,