www/apache
1
0
Fork 0
mirror of https://github.com/apache/httpd.git synced 2025-08-07 04:02:58 +03:00
Code Activity

* Fix a SEGFAULT by ensuring that buckets that may have been buffered in the

Browse Source 
network filters get flushed to the network. This is needed since
  these buckets have been created with the bucket allocator of the
  backend connection. This allocator either gets destroyed if
  conn->close is set or the worker address is not reusable which
  causes the connection to the backend to be closed or it will be used
  again by another frontend connection that wants to recycle the
  backend connection.
  In this case we could run into nasty race conditions (e.g. if the
  next user of the backend connection destroys the allocator before we
  sent the buckets to the network).

  Remark 1: Doing a setaside does not help here as the buckets remain
  created by the wrong allocator in this case.

  Remark 2: Yes, this creates a possible performance penalty in the case
  of pipelined requests as we may send only a small amount of data over
  the wire.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@604447 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Ruediger Pluem
2007-12-15 16:15:04 +00:00
parent 72109fff5c
commit d2a1cf5f8c
4 changed files with 59 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

53
modules/proxy/proxy_util.c
View File

@@ -1576,6 +1576,9 @@ static apr_status_t connection_cleanup(void *theconn)
{
proxy_conn_rec *conn = (proxy_conn_rec *)theconn;
proxy_worker *worker = conn->worker;
apr_bucket_brigade *bb;
conn_rec *c;
request_rec *r;
/*
* If the connection pool is NULL the worker
@@ -1596,8 +1599,48 @@ static apr_status_t connection_cleanup(void *theconn)
}
#endif
r = conn->r;
if (conn->need_flush && r) {
/*
* We need to ensure that buckets that may have been buffered in the
* network filters get flushed to the network. This is needed since
* these buckets have been created with the bucket allocator of the
* backend connection. This allocator either gets destroyed if
* conn->close is set or the worker address is not reusable which
* causes the connection to the backend to be closed or it will be used
* again by another frontend connection that wants to recycle the
* backend connection.
* In this case we could run into nasty race conditions (e.g. if the
* next user of the backend connection destroys the allocator before we
* sent the buckets to the network).
*
* Remark 1: Doing a setaside does not help here as the buckets remain
* created by the wrong allocator in this case.
*
* Remark 2: Yes, this creates a possible performance penalty in the case
* of pipelined requests as we may send only a small amount of data over
* the wire.
*/
c = r->connection;
bb = apr_brigade_create(r->pool, c->bucket_alloc);
if (r->eos_sent) {
/*
* If we have already sent an EOS bucket send directly to the
* connection based filters. We just want to flush the buckets
* if something hasn't been sent to the network yet.
*/
ap_fflush(c->output_filters, bb);
}
else {
ap_fflush(r->output_filters, bb);
}
apr_brigade_destroy(bb);
conn->r = NULL;
conn->need_flush = 0;
}
/* determine if the connection need to be closed */
if (conn->close) {
if (conn->close || !worker->is_address_reusable) {
apr_pool_t *p = conn->pool;
apr_pool_clear(p);
memset(conn, 0, sizeof(proxy_conn_rec));
@@ -1969,6 +2012,8 @@ ap_proxy_determine_connection(apr_pool_t *p, request_rec *r,
apr_status_t err = APR_SUCCESS;
apr_status_t uerr = APR_SUCCESS;
conn->r = r;
/*
* Break up the URL to determine the host to connect to
*/
@@ -2287,6 +2332,12 @@ PROXY_DECLARE(int) ap_proxy_connection_create(const char *proxy_function,
return OK;
}
/*
* We need to flush the buckets before we return the connection to the
* connection pool. See comment in connection_cleanup for why this is
* needed.
*/
conn->need_flush = 1;
bucket_alloc = apr_bucket_alloc_create(conn->scpool);
/*
* The socket is now open, create a new backend server connection