one more creation of continuation causes memory leak?

[오재경 <ge...@gmail.com>]

Sorry. i forget title. i resend.

----------------------------------
Hi.

I made a plugin. it's almost same to null-transform plugin but has one more
function.

it gets and delivers one of query string to transform so that it can sends
on defined bit per second according to query string.

The difference from null-transform is i made one more creation of
continuation.

In null-transform :

TSPluginInit
 |
 |---------------> TSContCreate(transform_plugin)
                             |
                             |---------------->transform_plugin
                                                        |
                                                        |---------------->
TSTransformCreate(null-transform)


In my plugin

TSPluginInit
 |
 |---------------> TSContCreate(transform_plugin)
                             |
                             |---------------->transform_plugin
                                                        |
                                                        |---------------->
TSContCreate(txn_cont_handler)   <------------------- one more Creation of
continuation !!!!!

                 |

                 |--------------------------> txn_cont_handler

                                                          |


|-----------------------------> TSTransformCreate(null-transform)


at first it looks fine. it worked well. but when i repeat tests and check
memory leak i found something wrong. the memory leak happens and finally
traffic server down showing "insufficient memory". Of course i appended
TSContDestroy as i created one more continuation. I repeated comparing
null-transform and new-transform. i think i followed the steps after
creation of continuation. I can't find what's wrong.

This is cut out code(i'd like to remind you it's almost same to
null-transform) :
...
static void
transform_add(TSHttpTxn txnp)
{
  TSVConn connp;

  // create a transform here!!
  connp = TSTransformCreate(null_transform, txnp);
  TSHttpTxnHookAdd(txnp, TS_HTTP_RESPONSE_TRANSFORM_HOOK, connp);
}

static int
txn_cont_handler(TSCont contp, TSEvent event, void *edata)
{
TSHttpTxn txnp = (TSHttpTxn) edata;

switch (event) {
case TS_EVENT_HTTP_READ_REQUEST_HDR :
...
TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
return 0;
case TS_EVENT_HTTP_CACHE_LOOKUP_COMPLETE :
// ready to create transform
transform_add(txnp);
TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
return 0;
case TS_EVENT_HTTP_READ_RESPONSE_HDR :
if (transformable(txnp)) {
// ready to create transform
transform_add(txnp);
}
TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
return 0;
case TS_EVENT_HTTP_TXN_CLOSE :
// Destroy continuation here!!!
   TSContDestroy(contp);
TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
return 0;
default :
break;
}
return 0;
}

static int
h264_transform_plugin(TSCont contp, TSEvent event, void *edata)
{
  TSHttpTxn txnp = (TSHttpTxn) edata;
  TSCont txn_contp;

  switch (event) {
case TS_EVENT_HTTP_TXN_START :
// Create parent continuation one more instead of creation of transform!!
txn_contp = TSContCreate(txn_cont_handler, NULL);
TSHttpTxnHookAdd(txnp, TS_HTTP_READ_REQUEST_HDR_HOOK, txn_contp);
TSHttpTxnHookAdd(txnp, TS_HTTP_CACHE_LOOKUP_COMPLETE_HOOK, txn_contp);
TSHttpTxnHookAdd(txnp, TS_HTTP_READ_RESPONSE_HDR_HOOK, txn_contp);
TSHttpTxnHookAdd(txnp, TS_HTTP_TXN_CLOSE_HOOK, txn_contp);
TSHttpTxnReenable(txnp, TS_EVENT_HTTP_CONTINUE);
return 0;
default:
break;
  }

  return 0;
}

void
TSPluginInit(int argc, const char *argv[])
{
  TSPluginRegistrationInfo info;
  TSCont contp;

// make a grandpa continuation
contp = TSContCreate(h264_transform_plugin, NULL);

// to save of query string
TSHttpHookAdd(TS_HTTP_TXN_START_HOOK, contp);

  return;
}