Implement buyramself action

ref: eosnetworkfoundation/eos-system-contracts#105

contracts/eosio.system/include/eosio.system/eosio.system.hpp

@@ -1110,6 +1110,17 @@ namespace eosiosystem {
          [[eosio::action]]
          void buyrambytes( const name& payer, const name& receiver, uint32_t bytes );
 
+         /**
+          * The buyramself action is designed to enhance the permission security by allowing an account to purchase RAM exclusively for itself.
+          * This action prevents the potential risk associated with standard actions like buyram and buyrambytes,
+          * which can transfer EOS tokens out of the account, acting as a proxy for eosio.token::transfer.
+          *
+          * @param account - the ram buyer and receiver,
+          * @param quant - the quantity of tokens to buy ram with.
+          */
+         [[eosio::action]]
+         void buyramself( const name& account, const asset& quant );
+
          /**
           * Logging for buyram & buyrambytes action
           *

contracts/eosio.system/ricardian/eosio.system.contracts.md.in

@@ -59,6 +59,17 @@ icon: @ICON_BASE_URL@/@RESOURCE_ICON_URI@
 
 {{payer}} buys RAM on behalf of {{receiver}} by paying {{quant}}. This transaction will incur a 0.5% fee out of {{quant}} and the amount of RAM delivered will depend on market rates.
 
+<h1 class="contract">buyramself</h1>
+
+---
+spec_version: "0.2.0"
+title: Buy RAM self
+summary: '{{nowrap account}} buys RAM to self by paying {{nowrap quant}}'
+icon: @ICON_BASE_URL@/@RESOURCE_ICON_URI@
+---
+
+{{account}} buys RAM to self by paying {{quant}}. This transaction will incur a 0.5% fee out of {{quant}} and the amount of RAM delivered will depend on market rates.
+
 <h1 class="contract">buyrambytes</h1>
 
 ---

contracts/eosio.system/src/delegate_bandwidth.cpp

@@ -31,6 +31,12 @@ namespace eosiosystem {
       buyram( payer, receiver, asset{ cost_plus_fee, core_symbol() } );
    }
 
+   /**
+    * Buy self ram action, ram can only be purchased to itself.
+    */
+   void system_contract::buyramself( const name& account, const asset& quant ) {
+      buyram( account, account, quant );
+   }
 
    /**
     *  When buying ram the payer irreversibly transfers quant to system contract and only

tests/eosio.system_ram_tests.cpp

@@ -63,4 +63,20 @@ BOOST_FIXTURE_TEST_CASE( ram_burn, eosio_system_tester ) try {
 
 } FC_LOG_AND_RETHROW()
 
+
+// buyramself
+BOOST_FIXTURE_TEST_CASE( buy_ram_self, eosio_system_tester ) try {
+   const std::vector<account_name> accounts = { "alice"_n };
+   create_accounts_with_resources( accounts );
+   const account_name alice = accounts[0];
+
+   transfer( config::system_account_name, alice, core_sym::from_string("100.0000"), config::system_account_name );
+   const uint64_t alice_before = get_total_stake( alice )["ram_bytes"].as_uint64();
+   BOOST_REQUIRE_EQUAL( success(), buyramself( alice, core_sym::from_string("1.0000")) );
+   const uint64_t alice_after = get_total_stake( alice )["ram_bytes"].as_uint64();
+   BOOST_REQUIRE_EQUAL( alice_before + 68375, alice_after );
+
+} FC_LOG_AND_RETHROW()
+
+
 BOOST_AUTO_TEST_SUITE_END()

tests/eosio.system_tester.hpp

@@ -281,6 +281,10 @@ class eosio_system_tester : public TESTER {
       return sellram( account_name(account), numbytes );
    }
 
+   action_result buyramself( const account_name& account, const asset& quant ) {
+      return push_action( account, "buyramself"_n, mvo()( "account",account)("quant",quant) );
+   }
+
    action_result push_action( const account_name& signer, const action_name &name, const variant_object &data, bool auth = true ) {
          string action_type_name = abi_ser.get_action_type(name);