solana: store custody account in config

Author: kcsongor

solana/programs/example-native-token-transfers/src/config.rs

@@ -35,6 +35,8 @@ pub struct Config {
     pub enabled_transceivers: Bitmap,
     /// Pause the program. This is useful for upgrades and other maintenance.
     pub paused: bool,
+    /// The custody account that holds tokens in locking mode.
+    pub custody: Pubkey,
 }
 
 impl Config {

solana/programs/example-native-token-transfers/src/instructions/initialize.rs

@@ -12,7 +12,6 @@ use crate::{
     queue::{outbox::OutboxRateLimit, rate_limit::RateLimitState},
 };
 
-// TODO: upgradeability
 #[derive(Accounts)]
 #[instruction(args: InitializeArgs)]
 pub struct Initialize<'info> {
@@ -102,6 +101,7 @@ pub fn initialize(ctx: Context<Initialize>, args: InitializeArgs) -> Result<()>
         // NOTE: can't be changed for now
         threshold: 1,
         enabled_transceivers: Bitmap::new(),
+        custody: ctx.accounts.custody.key(),
     });
 
     ctx.accounts.rate_limit.set_inner(OutboxRateLimit {

solana/programs/example-native-token-transfers/src/instructions/release_inbound.rs

@@ -104,7 +104,10 @@ pub struct ReleaseInboundUnlock<'info> {
     common: ReleaseInbound<'info>,
 
     /// CHECK: the token program checks if this indeed the right authority for the mint
-    #[account(mut)]
+    #[account(
+        mut,
+        address = common.config.custody
+    )]
     pub custody: InterfaceAccount<'info, token_interface::TokenAccount>,
 }
 

solana/programs/example-native-token-transfers/src/instructions/transfer.rs

@@ -171,8 +171,7 @@ pub struct TransferLock<'info> {
 
     #[account(
         mut,
-        token::mint = common.mint,
-        token::authority = common.token_authority,
+        address = common.config.custody
     )]
     pub custody: InterfaceAccount<'info, token_interface::TokenAccount>,
 }