1 files changed, 89 insertions, 0 deletions
diff --git a/src/loadctrl.c b/src/loadctrl.c
new file mode 100644
index 0000000..ad2ea84
--- /dev/null
+++ b/src/loadctrl.c
@@ -0,0 +1,89 @@
+/*
+** Copyright (c) 2014 D. Richard Hipp
+**
+** This program is free software; you can redistribute it and/or
+** modify it under the terms of the Simplified BSD License (also
+** known as the "2-Clause License" or "FreeBSD License".)
+
+** This program is distributed in the hope that it will be useful,
+** but without any warranty; without even the implied warranty of
+** merchantability or fitness for a particular purpose.
+**
+** Author contact information:
+**   drh@hwaci.com
+**   http://www.hwaci.com/drh/
+**
+*******************************************************************************
+**
+** This file contains code to check the host load-average and abort
+** CPU-intensive operations if the load-average is too high.
+*/
+#include "config.h"
+#include "loadctrl.h"
+#include <assert.h>
+
+/*
+** Return the load average for the host processor
+*/
+double load_average(void){
+#if !defined(_WIN32) && !defined(FOSSIL_OMIT_LOAD_AVERAGE)
+  double a[3];
+  if( getloadavg(a, 3)>0 ){
+    return a[0]>=0.000001 ? a[0] : 0.000001;
+  }
+#endif
+  return 0.0;
+}
+
+/*
+** COMMAND: test-loadavg
+**
+** %fossil test-loadavg
+**
+** Print the load average on the host machine.
+*/
+void loadavg_test_cmd(void){
+  fossil_print("load-average: %f\n", load_average());
+}
+
+/*
+** WEBPAGE:  test-overload
+**
+** Generate the response that would normally be shown only when
+** service is denied due to an overload condition.  This is for
+** testing of the overload warning page.
+*/
+void overload_page(void){
+  double mxLoad = atof(db_get("max-loadavg", "0.0"));
+  style_set_current_feature("test");
+  style_header("Server Overload");
+  @ <h2>The server load is currently too high.
+  @ Please try again later.</h2>
+  @ <p>Current load average: %f(load_average())<br>
+  @ Load average limit: %f(mxLoad)<br>
+  @ URL: %h(g.zBaseURL)%h(P("PATH_INFO"))<br>
+  @ Timestamp: %h(db_text("","SELECT datetime()"))Z</p>
+  style_finish_page();
+}
+
+/*
+** Abort the current page request if the load average of the host
+** computer is too high. Admin and Setup users are exempt from this
+** restriction.
+*/
+void load_control(void){
+  double mxLoad = atof(db_get("max-loadavg", "0.0"));
+#if 1
+  /* Disable this block only to test load restrictions */
+  if( mxLoad<=0.0 || mxLoad>=load_average() ) return;
+
+  login_check_credentials();
+  if(g.perm.Admin || g.perm.Setup){
+    return;
+  }
+#endif
+  overload_page();
+  cgi_set_status(503,"Server Overload");
+  cgi_reply();
+  exit(0);
+}