From c8fc0e15dd090214c0134128a7d589141f406835 Mon Sep 17 00:00:00 2001
From: arhag <arhag@users.noreply.github.com>
Date: Fri, 27 Apr 2018 23:05:57 -0400
Subject: [PATCH] reduce max_cpu limit for trx to what billed accounts can pay
 (and what the block limit can support)

This change still has not fixed the broken tests in wasm_tests.
---
 .../eosio/chain/transaction_context.hpp       |  7 ++--
 libraries/chain/transaction_context.cpp       | 34 ++++++++++++-------
 2 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/libraries/chain/include/eosio/chain/transaction_context.hpp b/libraries/chain/include/eosio/chain/transaction_context.hpp
index 415d78133..fbdde0120 100644
--- a/libraries/chain/include/eosio/chain/transaction_context.hpp
+++ b/libraries/chain/include/eosio/chain/transaction_context.hpp
@@ -7,8 +7,8 @@ namespace eosio { namespace chain {
 
    class transaction_context {
       public:
-         transaction_context( controller& c, 
-                              const signed_transaction& t, 
+         transaction_context( controller& c,
+                              const signed_transaction& t,
                               const transaction_id_type& trx_id )
          :control(c),
           id(trx_id),
@@ -33,7 +33,7 @@ namespace eosio { namespace chain {
          bool apply_actions      = true;
          bool is_input           = true;
 
-         fc::microseconds   delay; 
+         fc::microseconds   delay;
 
          vector<action_receipt>            executed;
 
@@ -51,7 +51,6 @@ namespace eosio { namespace chain {
          uint32_t                          net_usage = 0;
          //const transaction_metadata_ptr&   trx_meta;
          chainbase::database::session      undo_session;
-         flat_set<account_name>            bill_to_accounts;
    };
 
 } }
diff --git a/libraries/chain/transaction_context.cpp b/libraries/chain/transaction_context.cpp
index 800bf9185..d8d651947 100644
--- a/libraries/chain/transaction_context.cpp
+++ b/libraries/chain/transaction_context.cpp
@@ -18,12 +18,31 @@ namespace eosio { namespace chain {
          control.validate_expiration( trx );
          record_transaction( id, trx.expiration ); /// checks for dupes
       }
-      max_cpu = control.get_global_properties().configuration.max_transaction_cpu_usage;
-      // TODO: reduce max_cpu to the minimum of the amount that the paying accounts can afford to pay
+
+      auto& rl = control.get_mutable_resource_limits_manager();
+      auto current_slot = block_timestamp_type(control.pending_block_time()).slot;
+
+      flat_set<account_name> bill_to_accounts;
+      for( const auto& act : trx.actions ) {
+         for( const auto& auth : act.authorization )
+            bill_to_accounts.insert( auth.actor );
+      }
+
+      rl.add_transaction_usage( bill_to_accounts, 0, 0, current_slot ); // Update usage values of accounts to reflect new time
+
+      max_cpu = std::min( rl.get_block_cpu_limit(),
+                          static_cast<uint64_t>(control.get_global_properties().configuration.max_transaction_cpu_usage) );
+      for( const auto& a : bill_to_accounts ) {
+         auto l = rl.get_account_cpu_limit(a);
+         if( l >= 0 )
+            max_cpu = std::min( max_cpu, static_cast<uint64_t>(l) ); // reduce max_cpu to the amount the account is able to pay
+      }
+
       uint64_t trx_specified_cpu_usage_limit = uint64_t(trx.max_kcpu_usage.value)*1024; // overflow checked in transaction_header::validate()
       if( trx_specified_cpu_usage_limit > 0 )
          max_cpu = std::min( max_cpu, trx_specified_cpu_usage_limit );
 
+
       if( apply_context_free ) {
          for( const auto& act : trx.context_free_actions ) {
             dispatch_action( act, act.account, true );
@@ -38,23 +57,14 @@ namespace eosio { namespace chain {
           schedule_transaction();
       }
 
-      for( const auto& act : trx.actions ) {
-         for( const auto& auth : act.authorization )
-            bill_to_accounts.insert( auth.actor );
-      }
-
       trace->cpu_usage = ((trace->cpu_usage + 1023)/1024)*1024; // Round up to nearest multiple of 1024
 
       EOS_ASSERT( trace->cpu_usage <= max_cpu, tx_resource_exhausted,
                   "cpu usage of transaction is too high: ${actual_net_usage} > ${cpu_usage_limit}",
                   ("actual_net_usage", trace->cpu_usage)("cpu_usage_limit", max_cpu) );
 
-      auto& rl = control.get_mutable_resource_limits_manager();
-
-      flat_set<account_name> bta( bill_to_accounts.begin(), bill_to_accounts.end() );
       FC_ASSERT( net_usage % 8 == 0, "net_usage must be a multiple of word size (8)" );
-      rl.add_transaction_usage( bta, trace->cpu_usage, net_usage, block_timestamp_type(control.pending_block_time()).slot );
-
+      rl.add_transaction_usage( bill_to_accounts, trace->cpu_usage, net_usage, current_slot );
    }
 
    void transaction_context::squash() {
-- 
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