mod_proxy: Handle ap_proxy_buckets_lifetime_transform() errors.

* modules/proxy/mod_proxy.h,modules/proxy/proxy_util.c:
  Add ap_proxy_fill_error_brigade() to factorize proxy error handling
  on the client connection side.

* modules/proxy/mod_proxy_{http,ajp,uwsgi}.c:
  Use ap_proxy_fill_error_brigade() where needed, including when an
  empty brigade is returned on the backend side or when calling
  ap_proxy_buckets_lifetime_transform fails.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1893595 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 33 insertions, 28 deletions

diff --git a/modules/proxy/mod_proxy_uwsgi.c b/modules/proxy/mod_proxy_uwsgi.c
index 971eaa59dc..2c493cdab4 100644
--- a/modules/proxy/mod_proxy_uwsgi.c
+++ b/modules/proxy/mod_proxy_uwsgi.c
@@ -379,14 +379,11 @@ static int uwsgi_response(request_rec *r, proxy_conn_rec * backend,
         int status = r->status;
         r->status = HTTP_OK;
         r->status_line = NULL;
-
-        apr_brigade_cleanup(bb);
-        apr_brigade_cleanup(pass_bb);
-
         return status;
     }
 
     while (!finish) {
+        apr_brigade_cleanup(bb);
         rv = ap_get_brigade(rp->input_filters, bb,
                             AP_MODE_READBYTES, mode, conf->io_buffer_size);
         if (APR_STATUS_IS_EAGAIN(rv)
@@ -396,52 +393,60 @@ static int uwsgi_response(request_rec *r, proxy_conn_rec * backend,
             if (ap_pass_brigade(r->output_filters, bb) || c->aborted) {
                 break;
             }
-            apr_brigade_cleanup(bb);
             mode = APR_BLOCK_READ;
             continue;
         }
-        else if (rv == APR_EOF) {
+        if (rv == APR_EOF) {
             break;
         }
-        else if (rv != APR_SUCCESS) {
-            ap_proxy_backend_broke(r, bb);
+        if (rv != APR_SUCCESS || APR_BRIGADE_EMPTY(bb)) {
+            int status = HTTP_BAD_GATEWAY;
+            if (rv == APR_SUCCESS) {
+                ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(10294)
+                              "Unexpected empty data reading uwscgi response");
+                status = HTTP_INTERNAL_SERVER_ERROR;
+            }
+            apr_brigade_cleanup(bb);
+            ap_proxy_fill_error_brigade(r, status, bb, -1);
             ap_pass_brigade(r->output_filters, bb);
             backend_broke = 1;
             break;
         }
 
+        /* found the last brigade? */
+        if (APR_BUCKET_IS_EOS(APR_BRIGADE_LAST(bb)))
+            finish = 1;
+
         mode = APR_NONBLOCK_READ;
         apr_brigade_length(bb, 0, &readbytes);
         backend->worker->s->read += readbytes;
 
-        if (APR_BRIGADE_EMPTY(bb)) {
-            apr_brigade_cleanup(bb);
+        rv = ap_proxy_buckets_lifetime_transform(r, bb, pass_bb);
+        if (rv != APR_SUCCESS) {
+            /* Half way through a response, our only option is
+             * to notice the output filters and then disconnect the
+             * client and backend.
+             */
+            if (!APR_BRIGADE_EMPTY(pass_bb)) {
+                /* Pass what we have still */
+                ap_pass_brigade(r->output_filters, pass_bb);
+                apr_brigade_cleanup(pass_bb);
+            }
+            ap_proxy_fill_error_brigade(r, HTTP_INTERNAL_SERVER_ERROR,
+                                        pass_bb, -1);
+            ap_pass_brigade(r->output_filters, pass_bb);
+            apr_brigade_cleanup(pass_bb);
+
+            backend_broke = 1;
             break;
         }
-
-        ap_proxy_buckets_lifetime_transform(r, bb, pass_bb);
-
-        /* found the last brigade? */
-        if (APR_BUCKET_IS_EOS(APR_BRIGADE_LAST(bb)))
-            finish = 1;
-
-        /* do not pass chunk if it is zero_sized */
-        apr_brigade_length(pass_bb, 0, &readbytes);
-
-        if ((readbytes > 0
-             && ap_pass_brigade(r->output_filters, pass_bb) != APR_SUCCESS)
+        if (ap_pass_brigade(r->output_filters, pass_bb) != APR_SUCCESS
             || c->aborted) {
             finish = 1;
         }
-
-        apr_brigade_cleanup(bb);
         apr_brigade_cleanup(pass_bb);
     }
 
-    e = apr_bucket_eos_create(c->bucket_alloc);
-    APR_BRIGADE_INSERT_TAIL(bb, e);
-    ap_pass_brigade(r->output_filters, bb);
-
     apr_brigade_cleanup(bb);
 
     if (c->aborted || backend_broke) {