Commit 767deda8 authored by Yann Ylavic's avatar Yann Ylavic
Browse files

core: ap_filter_output_pending() to flush outer most filters first. 

Since previous output filters may use ap_filter_should_yield() to determine
whether they should send more data (e.g. ap_request_core_filter), we need
to flush pending data from the core output filter first, and so on up the
chain.

Otherwise we may enter an infinite loop where ap_request_core_filter() does
nothing on ap_filter_output_pending() called from MPM event.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1837822 13f79535-47bb-0310-9956-ffa450edef68
parent d24a295f

server/util_filter.c

+14 −10
Changes for server/util_filter.c: 14 added lines, 10 removed lines.
Original line number Diff line number Diff line
@@ -818,6 +818,12 @@ AP_DECLARE(apr_status_t) ap_filter_reinstate_brigade(ap_filter_t *f, 
    int eor_buckets_in_brigade, morphing_bucket_in_brigade;

    core_server_config *conf;

 

    ap_log_cerror(APLOG_MARK, APLOG_TRACE6, 0, f->c,

                  "reinstate %s brigade to %s brigade in '%s' output filter",

                  (!f->bb || APR_BRIGADE_EMPTY(f->bb) ? "empty" : "full"),

                  (APR_BRIGADE_EMPTY(bb) ? "empty" : "full"),

                  f->frec->name);



    if (f->bb && !APR_BRIGADE_EMPTY(f->bb)) {

        APR_BRIGADE_PREPEND(bb, f->bb);

    }
@@ -828,12 +834,6 @@ AP_DECLARE(apr_status_t) ap_filter_reinstate_brigade(ap_filter_t *f, 
 

    *flush_upto = NULL;



    ap_log_cerror(APLOG_MARK, APLOG_TRACE6, 0, f->c,

                  "reinstate %s brigade to %s brigade in '%s' output filter",

                  (!f->bb || APR_BRIGADE_EMPTY(f->bb) ? "empty" : "full"),

                  (APR_BRIGADE_EMPTY(bb) ? "empty" : "full"),

                  f->frec->name);



    /*

     * Determine if and up to which bucket we need to do a blocking write:

     *
@@ -1005,9 +1005,13 @@ AP_DECLARE_NONSTD(int) ap_filter_output_pending(conn_rec *c) 
    bb = ap_reuse_brigade_from_pool("ap_fop_bb", c->pool,

                                    c->bucket_alloc);



    for (f = APR_RING_FIRST(c->pending_filters);

    /* Flush outer most filters first for ap_filter_should_yield(f->next)

     * to be relevant in the previous ones (e.g. ap_request_core_filter()

     * won't pass its buckets if its next filters yields already).

     */

    for (f = APR_RING_LAST(c->pending_filters);

         f != APR_RING_SENTINEL(c->pending_filters, ap_filter_t, pending);

         f = APR_RING_NEXT(f, pending)) {

         f = APR_RING_PREV(f, pending)) {

        if (f->frec->direction == AP_FILTER_OUTPUT && f->bb

                && !APR_BRIGADE_EMPTY(f->bb)) {

            apr_status_t rv;
@@ -1038,9 +1042,9 @@ AP_DECLARE_NONSTD(int) ap_filter_input_pending(conn_rec *c) 
        return DECLINED;

    }



    for (f = APR_RING_FIRST(c->pending_filters);

    for (f = APR_RING_LAST(c->pending_filters);

         f != APR_RING_SENTINEL(c->pending_filters, ap_filter_t, pending);

         f = APR_RING_NEXT(f, pending)) {

         f = APR_RING_PREV(f, pending)) {

        if (f->frec->direction == AP_FILTER_INPUT && f->bb) {

            apr_bucket *e = APR_BRIGADE_FIRST(f->bb);