From c9d78382130691120a69329bc05e8b9563d93d03 Mon Sep 17 00:00:00 2001
From: Justine Tunney <jtunney@gmail.com>
Date: Fri, 5 Aug 2022 15:42:17 -0700
Subject: [PATCH] Enter meltdown mode if ProgramMaxWorkers triggers

---
 tool/net/help.txt  | 8 ++++----
 tool/net/redbean.c | 8 +++++++-
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/tool/net/help.txt b/tool/net/help.txt
index fe9b83f5f..c3dd4c4b7 100644
--- a/tool/net/help.txt
+++ b/tool/net/help.txt
@@ -741,10 +741,10 @@ FUNCTIONS
 
           Turns Lua data structure into JSON string.
 
-          Since Lua uses tables are both hashmaps and arrays, we use a
-          simple fast algorithm for telling the two apart. Tables with
-          non-zero length (as reported by `#`) are encoded as arrays,
-          and any non-array elements are ignored. For example:
+          Since Lua tables are both hashmaps and arrays, we use a simple
+          fast algorithm for telling the two apart. Tables with non-zero
+          length (as reported by `#`) are encoded as arrays, and any
+          non-array elements are ignored. For example:
 
               >: EncodeJson({2})
               "[2]"
diff --git a/tool/net/redbean.c b/tool/net/redbean.c
index 43790cfe4..1c61afa3b 100644
--- a/tool/net/redbean.c
+++ b/tool/net/redbean.c
@@ -4755,6 +4755,7 @@ static int LuaProgramMaxWorkers(lua_State *L) {
   }
   lua_pushinteger(L, maxworkers);
   if (lua_isinteger(L, 1)) maxworkers = lua_tointeger(L, 1);
+  maxworkers = MAX(maxworkers, 1);
   return 1;
 }
 
@@ -6749,6 +6750,12 @@ static int HandleConnection(size_t i) {
   if ((client = accept4(servers.p[i].fd, &clientaddr, &clientaddrsize,
                         SOCK_CLOEXEC)) != -1) {
     startconnection = nowl();
+    if (UNLIKELY(maxworkers) && shared->workers >= maxworkers) {
+      EnterMeltdownMode();
+      SendServiceUnavailable();
+      close(client);
+      return 0;
+    }
     VERBOSEF("(srvr) accept %s via %s", DescribeClient(), DescribeServer());
     messageshandled = 0;
     if (hasonclientconnection && LuaOnClientConnection()) {
@@ -6939,7 +6946,6 @@ static int HandlePoll(int ms) {
         if (!polls[pollid].revents) continue;
         if (polls[pollid].fd < 0) continue;
         if (polls[pollid].fd) {
-          if (maxworkers && shared->workers >= maxworkers) continue;
           // handle listen socket
           lua_repl_lock();
           serverid = pollid - 1;