------------------------------------------------------------
revno: 13935
revision-id: squid3@treenet.co.nz-20151014052929-7yesi94pu0i2gpwq
parent: squid3@treenet.co.nz-20151011053619-x5o37tyg0ymkpe3z
fixes bug: http://bugs.squid-cache.org/show_bug.cgi?id=3574
committer: Amos Jeffries <squid3@treenet.co.nz>
branch nick: 3.5
timestamp: Tue 2015-10-13 22:29:29 -0700
message:
  Bug 3574: crashes on reconfigure and startup
  
  When Squid receives a reconfigure signal before its signal handler
  has been registered on startup it will crash with unhandled signal
  exceptions. This can be triggered on system boot when a resolv.conf
  alteration signal wins a race with the daemon service initialization.
  
  Fix:
   Register the reconfigure signal handler early and ignoring signals
   until initial squid.conf load has completed.
  
  
  When Squid receives a reconfigure signal while it is already in the
  process of reconfiguring, the two async sequences can interfere and
  result in confusing fatal error or crashes.
  
  Fix:
   Only allow one reconfigure sequence to be initiated at a time.
  
  Also, if shutdown signal has been received while waiting for a
  reconfigure to finish, let shutdown take precedence over any pending
  reconfigure repeats.
  
  
   Based on work by Clint Byrum and D J Gardner, Ubuntu
------------------------------------------------------------
# Bazaar merge directive format 2 (Bazaar 0.90)
# revision_id: squid3@treenet.co.nz-20151014052929-7yesi94pu0i2gpwq
# target_branch: http://bzr.squid-cache.org/bzr/squid3/3.5
# testament_sha1: 6d385c74e2d6f1943f237dac44c2c061576c19a7
# timestamp: 2015-10-14 05:50:59 +0000
# source_branch: http://bzr.squid-cache.org/bzr/squid3/3.5
# base_revision_id: squid3@treenet.co.nz-20151011053619-\
#   x5o37tyg0ymkpe3z
# 
# Begin patch
=== modified file 'src/main.cc'
--- src/main.cc	2015-07-29 08:56:44 +0000
+++ src/main.cc	2015-10-14 05:29:29 +0000
@@ -224,8 +224,10 @@
     PROF_start(SignalEngine_checkEvents);
 
     if (do_reconfigure) {
-        mainReconfigureStart();
-        do_reconfigure = 0;
+        if (!reconfiguring && configured_once) {
+            mainReconfigureStart();
+            do_reconfigure = 0;
+        } // else wait until previous reconfigure is done
     } else if (do_rotate) {
         mainRotate();
         do_rotate = 0;
@@ -889,6 +891,10 @@
     writePidFile();     /* write PID file */
 
     reconfiguring = 0;
+
+    // ignore any pending re-reconfigure signals if shutdown received
+    if (do_shutdown)
+        do_reconfigure = 0;
 }
 
 static void
@@ -991,6 +997,7 @@
 
     squid_signal(SIGPIPE, SIG_IGN, SA_RESTART);
     squid_signal(SIGCHLD, sig_child, SA_NODEFER | SA_RESTART);
+    squid_signal(SIGHUP, reconfigure, SA_RESTART);
 
     setEffectiveUser();
 
@@ -1156,8 +1163,6 @@
 
 #endif
 
-    squid_signal(SIGHUP, reconfigure, SA_RESTART);
-
     squid_signal(SIGTERM, shut_down, SA_NODEFER | SA_RESETHAND | SA_RESTART);
 
     squid_signal(SIGINT, shut_down, SA_NODEFER | SA_RESETHAND | SA_RESTART);
@@ -1402,6 +1407,7 @@
         Format::Token::Init(); // XXX: temporary. Use a runners registry of pre-parse runners instead.
 
         try {
+            do_reconfigure = 0; // ignore any early (boot/startup) reconfigure signals
             parse_err = parseConfigFile(ConfigFile);
         } catch (...) {
             // for now any errors are a fatal condition...