You are a few weeks too late. :-) See:
http://issues.apache.org/jira/browse/MODPYTHON-98 There are whole bunch of little issues with adding handlers using req.add_handler(). For this one you seem to have tread much the same path as I did. Graham Joseph Barillari wrote .. > Hi, > > So far, I really like mod_python -- it's a great piece of > software. But I think I've found a small bug. > > I've noticed that adding a handler using add_handler prompts apache to > segfault if no statically registered (e.g., specified in the apache > conf files) handlers of the same category (e.g., PythonLogHandler, > PythonTransHandler) are present. I've tested this in both the release > version (314) and version 325b (albeit more thoroughly in the former). > > Here's how I triggered the bug: > > Add this to apache2.conf: > PythonPath "sys.path+[(the path goes here)]" > PythonTransHandler crashbug > > crashbug.py contains: > > from mod_python import apache > > def transhandler(req): > req.add_handler("PythonLogHandler","foo::loghandler") > return apache.OK > > foo contains: > > from mod_python import apache > > def loghandler(req): > import sys > sys.stderr.write("foo: saw request type:" + req.method + "\n") > return apache.OK > > If I run apache > > sudo /usr/sbin/apache2 -X > > and tickle the server: > > echo -e "GET / HTTP/1.0\n\n" | nc localhost 8080 > > ...apache segfaults. > > On the other hand, if I add the line > > PythonLogHandler notfoo > > to apache2.conf, where notfoo.py is identical to foo except that > "foo:" is replaced with "notfoo", I get the expected two lines in the > log, and no crash. > > Here's the trace: > > Program received signal SIGSEGV, Segmentation fault. > [Switching to Thread -1214269216 (LWP 21283)] > 0xb76dddb3 in hlist_copy (p=0x8158fa8, hle=0x0) at hlist.c:91 > 91 head->handler = apr_pstrdup(p, hle->handler); > (gdb) bt > #0 0xb76dddb3 in hlist_copy (p=0x8158fa8, hle=0x0) at hlist.c:91 > #1 0xb76dd9aa in MpHList_FromHLEntry (hle=0x0) at hlistobject.c:49 > #2 0xb76e59b6 in python_handler (req=0x8238480, phase=0xb76e804c > "PythonLogHandler") > at mod_python.c:1029 > #3 0x08086086 in ap_run_log_transaction () > #4 0x0806963e in ap_process_request () > #5 0x08064b19 in _start () > > > I suspect the problem is in this part of mod_python.c: > > Here's my understanding (please correct me if I'm wrong). If hle is > NULL (i.e., there were no handlers of this type registered in the > apache conf), but dynhle is not null (we registered a dynamic > handler), we continue processing... > > if (! (hle || dynhle)) { > /* nothing to do here */ > return DECLINED; > } > > /* determine interpreter to use */ > interp_name = select_interp_name(req, NULL, conf, hle, NULL, 0); > > /* get/create interpreter */ > idata = get_interpreter(interp_name, req->server); > > if (!idata) > return HTTP_INTERNAL_SERVER_ERROR; > > /* create/acquire request object */ > request_obj = get_request_object(req, interp_name, phase); > > /* remember the extension if any. used by publisher */ > if (ext) > request_obj->extension = apr_pstrdup(req->pool, ext); > > But then, we try to create an MpHList from hle, which is NULL -- prompting > a crash a few levels down. > > /* create a hahdler list object */ > request_obj->hlo = (hlistobject *)MpHList_FromHLEntry(hle); > > > Here's how I fixed it: > > --- /home/jdb/dl/mpsvn/mod_python-3.1.4/src/mod_python.c 2005-01-29 > 16:25:28.000000000 > -0500 > +++ mod_python.c 2006-01-04 16:59:13.000000000 -0500 > @@ -1026,13 +1026,18 @@ > request_obj->extension = apr_pstrdup(req->pool, ext); > > /* create a hahdler list object */ > - request_obj->hlo = (hlistobject *)MpHList_FromHLEntry(hle); > - > - /* add dynamically registered handlers, if any */ > - if (dynhle) { > + if (hle) { > + request_obj->hlo = (hlistobject *)MpHList_FromHLEntry(hle); > + /* add dynamically registered handlers, if any */ > + if (dynhle) { > MpHList_Append(request_obj->hlo, dynhle); > + } > } > - > + else { > + /* hle was NULL; so create hlo from dynhle */ > + request_obj->hlo = (hlistobject *)MpHList_FromHLEntry(dynhle); > + } > + > /* > * Here is where we call into Python! > * This is the C equivalent of > > AFAIK, this works -- but I'm new at this. > > best regards, > > Joe
