* mod_proxy_http.c

   Ensure that the EOC bucket is inserted BEFORE an EOS bucket in bb as
   some resource filters like mod_deflate pass everything up to the EOS
   down the chain immediately and sent the remainder of the brigade later
   (or even never). But in this case the ap_http_header_filter does not
   get out of our way soon enough.

   http_filters.c
   Remove all data buckets that are in a brigade after an EOC bucket
   was seen, as an EOC bucket tells us that no (further) resource
   and protocol data should go out to the client. OTOH meta buckets
   are still welcome as they might trigger needed actions down in
   the chain (e.g. in network filters like SSL).
   Remark 1: It is needed to dump ALL data buckets in the brigade
             since an filter in between might have inserted data
             buckets BEFORE the EOC bucket sent by the original
             sender and we do NOT want this data to be sent.
   Remark 2: Dumping all data buckets here does not necessarily mean
             that no further data is send to the client as:
             1. Network filters like SSL can still be triggered via
                meta buckets to talk with the client e.g. for a
                clean shutdown.
             2. There could be still data that was buffered before
                down in the chain that gets flushed by a FLUSH or an
                EOS bucket.

PR: 37770

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@660726 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/modules/http/http_filters.c b/modules/http/http_filters.c
index 0bf3bc0d94509467423ea642c470d5881ca2b8c3..5787c85a3a3257c94e34ca95cec375ffee30b49d 100644 (file)
--- a/modules/http/http_filters.c
+++ b/modules/http/http_filters.c
@@ -1569,13 +1569,24 @@ AP_DECLARE(long) ap_get_client_block(request_rec *r, char *buffer,
     return bufsiz;
 }
 
+/* Context struct for ap_http_outerror_filter */
+typedef struct {
+    int seen_eoc;
+} outerror_filter_ctx_t;
+
 /* Filter to handle any error buckets on output */
 apr_status_t ap_http_outerror_filter(ap_filter_t *f,
                                      apr_bucket_brigade *b)
 {
     request_rec *r = f->r;
+    outerror_filter_ctx_t *ctx = (outerror_filter_ctx_t *)(f->ctx);
     apr_bucket *e;
 
+    /* Create context if none is present */
+    if (!ctx) {
+        ctx = apr_pcalloc(r->pool, sizeof(outerror_filter_ctx_t));
+        f->ctx = ctx;
+    }
     for (e = APR_BRIGADE_FIRST(b);
          e != APR_BRIGADE_SENTINEL(b);
          e = APR_BUCKET_NEXT(e))
@@ -1589,6 +1600,40 @@ apr_status_t ap_http_outerror_filter(ap_filter_t *f,
                 /* stream aborted and we have not ended it yet */
                 r->connection->keepalive = AP_CONN_CLOSE;
             }
+            continue;
+        }
+        /* Detect EOC buckets and memorize this in the context. */
+        if (AP_BUCKET_IS_EOC(e)) {
+            ctx->seen_eoc = 1;
+        }
+    }
+    /*
+     * Remove all data buckets that are in a brigade after an EOC bucket
+     * was seen, as an EOC bucket tells us that no (further) resource
+     * and protocol data should go out to the client. OTOH meta buckets
+     * are still welcome as they might trigger needed actions down in
+     * the chain (e.g. in network filters like SSL).
+     * Remark 1: It is needed to dump ALL data buckets in the brigade
+     *           since an filter in between might have inserted data
+     *           buckets BEFORE the EOC bucket sent by the original
+     *           sender and we do NOT want this data to be sent.
+     * Remark 2: Dumping all data buckets here does not necessarily mean
+     *           that no further data is send to the client as:
+     *           1. Network filters like SSL can still be triggered via
+     *              meta buckets to talk with the client e.g. for a
+     *              clean shutdown.
+     *           2. There could be still data that was buffered before
+     *              down in the chain that gets flushed by a FLUSH or an
+     *              EOS bucket.
+     */
+    if (ctx->seen_eoc) {
+        for (e = APR_BRIGADE_FIRST(b);
+             e != APR_BRIGADE_SENTINEL(b);
+             e = APR_BUCKET_NEXT(e))
+        {
+            if (!APR_BUCKET_IS_METADATA(e)) {
+                APR_BUCKET_REMOVE(e);
+            }
         }
     }
 

diff --git a/modules/proxy/mod_proxy_http.c b/modules/proxy/mod_proxy_http.c
index 5ee75c029293f82e1be80c9b629433d9dea43e53..582a4a82362c92bd01e2587de8e0034b888cc191 100644 (file)
--- a/modules/proxy/mod_proxy_http.c
+++ b/modules/proxy/mod_proxy_http.c
@@ -1364,6 +1364,8 @@ apr_status_t ap_proxy_http_process_response(apr_pool_t * p, request_rec *r,
              * not do a retry.
              */
             if (r->proxyreq == PROXYREQ_REVERSE && c->keepalives) {
+                apr_bucket *eos;
+
                 ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
                               "proxy: Closing connection to client because"
                               " reading from backend server %s failed. Number"
@@ -1372,10 +1374,26 @@ apr_status_t ap_proxy_http_process_response(apr_pool_t * p, request_rec *r,
                 ap_proxy_backend_broke(r, bb);
                 /*
                  * Add an EOC bucket to signal the ap_http_header_filter
-                 * that it should get out of our way
+                 * that it should get out of our way, BUT ensure that the
+                 * EOC bucket is inserted BEFORE an EOS bucket in bb as
+                 * some resource filters like mod_deflate pass everything
+                 * up to the EOS down the chain immediately and sent the
+                 * remainder of the brigade later (or even never). But in
+                 * this case the ap_http_header_filter does not get out of
+                 * our way soon enough.
                  */
                 e = ap_bucket_eoc_create(c->bucket_alloc);
-                APR_BRIGADE_INSERT_TAIL(bb, e);
+                eos = APR_BRIGADE_LAST(bb);
+                while ((APR_BRIGADE_SENTINEL(bb) != eos)
+                       && !APR_BUCKET_IS_EOS(eos)) {
+                    eos = APR_BUCKET_PREV(eos);
+                }
+                if (eos == APR_BRIGADE_SENTINEL(bb)) {
+                    APR_BRIGADE_INSERT_TAIL(bb, e);
+                }
+                else {
+                    APR_BUCKET_INSERT_BEFORE(eos, e);
+                }
                 ap_pass_brigade(r->output_filters, bb);
                 /* Need to return OK to avoid sending an error message */
                 return OK;