From cb15f13431e8433eda8b25b178e3b48b1b02de36 Mon Sep 17 00:00:00 2001
From: bwarsaw
Date: Thu, 3 May 2001 21:18:25 +0000
Subject: main(): Add an explicit call to sys.exit() in the sigterm_handler()
 so that race conditions can't trick us into trying to Save() when we don't
 have the list lock.

---
 Mailman/Cgi/admindb.py | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/Mailman/Cgi/admindb.py b/Mailman/Cgi/admindb.py
index cc061be26..72680ed9e 100644
--- a/Mailman/Cgi/admindb.py
+++ b/Mailman/Cgi/admindb.py
@@ -16,6 +16,7 @@
 
 """Produce and process the pending-approval items for a list."""
 
+import sys
 import os
 import types
 import cgi
@@ -75,18 +76,27 @@ def main():
     doc = Document()
     doc.set_language(mlist.preferred_language)
     
-    # Lock the list for the next operation.  BAW: Strictly speaking, the list
-    # should not need to be locked just to read the request database.  However
-    # the request database asserts that the list is locked in order to load
-    # it and it's not worth complicating that logic.
+    # We need a signal handler to catch the SIGTERM that can come from Apache
+    # when the user hits the browser's STOP button.  See the comment in
+    # admin.py for details.
     #
-    # Also, see the comment in admin.py about the need for the signal handler.
+    # BAW: Strictly speaking, the list should not need to be locked just to
+    # read the request database.  However the request database asserts that
+    # the list is locked in order to load it and it's not worth complicating
+    # that logic.
     def sigterm_handler(signum, frame, mlist=mlist):
+        # Make sure the list gets unlocked...
         mlist.Unlock()
+        # ...and ensure we exit, otherwise race conditions could cause us to
+        # enter MailList.Save() while we're in the unlocked state, and that
+        # could be bad!
+        sys.exit(0)
 
     mlist.Lock()
     try:
+        # Install the emergency shutdown signal handler
         signal.signal(signal.SIGTERM, sigterm_handler)
+
         realname = mlist.real_name
         if not cgidata.keys():
             # If this is not a form submission (i.e. there are no keys in the
-- 
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