Gatling EMFILE patches

diff -u -r1.322 -r1.324
--- gatling.c   20 Jul 2023 09:18:52 -0000  1.322
+++ gatling.c   21 Nov 2024 16:06:23 -0000  1.324
@@ -580,6 +580,8 @@

 int limit_to_lan;

+int dummy_fd_for_EMFILE;
+
 static void accept_server_connection(int64 i,struct http_data* H,unsigned long ftptimeout_secs,tai6464 nextftp) {
   /* This is an FTP or HTTP(S) or SMB server connection.
     * This read event means that someone connected to us.
@@ -593,6 +595,7 @@

   while (1) {
     int punk;
+emfile_emergency:
 #ifdef __broken_itojun_v6__
     if (H->t==HTTPSERVER4 || H->t==FTPSERVER4
 #ifdef SUPPORT_SMB
@@ -608,6 +611,36 @@
     } else
 #endif
       n=socket_accept6(i,ip,&port,&scope_id);
+    if (n==-1 && errno==EMFILE) {
+      /* This is an exceptional situation. We ran into the limit on open
+       * file descriptors. If we just do nothing, we'll create an
+       * infinite loop because libowfat will just continue reporting the
+       * same fd over and over. But we can't drop the connection attempt
+       * without having accept succeed and then calling close on the new
+       * fd in the socket API. So we kept a dummy fd around for this
+       * occasion. */
+      if (dummy_fd_for_EMFILE==-1) {
+   buffer_putsflush(buffer_1,"EMFILE emergency close didn't work!\n");
+   exit(111);
+      }
+      close(dummy_fd_for_EMFILE);
+      dummy_fd_for_EMFILE=-1;
+      goto emfile_emergency;
+    }
+    if (dummy_fd_for_EMFILE==-1) {
+      if (n!=-1) {
+   buffer_puts(buffer_1,"close/emfile ");
+   buffer_putulong(buffer_1,n);
+   buffer_putnlflush(buffer_1);
+   close(n);   // we just made space for an fd, so the accept
+      }
+           // should have gone through.
+      dummy_fd_for_EMFILE=dup(0);
+      if (dummy_fd_for_EMFILE==-1) {
+   buffer_putsflush(buffer_1,"EMFILE emergency dup failed!\n");
+   exit(111);
+      }
+    }
     if (n==-1) break;
     punk=new_request_from_ip(ip,Now)==1;
     ++cps1;
@@ -1533,6 +1566,12 @@
   pid_t* Instances;
 #endif

+  dummy_fd_for_EMFILE=dup(0);
+  if (dummy_fd_for_EMFILE==-1) {
+    perror("dup");
+    exit(111);
+  }
+
   initdircache();
   maxlngdelta=1;