[PATCH] 'clogging' input filters and the event MPM

[Paul Querna]

Attached is a patch that should let people run mod_ssl under the Event MPM.

Previously, the event mpm would put a socket into its event thread to
wait for input, but due to issues with how mod_ssl might be buffering
data (or the entire request) in it, this would cause SSL'ized requests
to stall and fail with the event mpm.

The attach patch adds a new field, clogging_input_filters, to the
conn_rec. When this field is true, the event mpm will run a connection
just like the worker mpm is -- that is a single thread will run the
entire connection, including keepalives.

Thoughts on committing this to trunk?

Thanks,

-Paul

Index: server/mpm/experimental/event/event.c
===================================================================
--- server/mpm/experimental/event/event.c       (revision 545614)
+++ server/mpm/experimental/event/event.c       (working copy)
@@ -620,6 +620,16 @@
         pt = cs->pfd.client_data;
     }
 
+    if (c->clogging_input_filters && !c->aborted) {
+        /* Since we have an input filter which 'cloggs' the input stream,
+         * like mod_ssl, lets just do the normal read from input filters,
+         * like the Worker MPM does.
+         */
+        ap_run_process_connection(c);
+        ap_lingering_close(c);
+        return 0;
+    }
+
 read_request:
     if (cs->state == CONN_STATE_READ_REQUEST_LINE) {
         if (!c->aborted) {
Index: server/core.c
===================================================================
--- server/core.c       (revision 545614)
+++ server/core.c       (working copy)
@@ -3803,6 +3803,7 @@
     c->cs->c = c;
     c->cs->p = ptrans;
     c->cs->bucket_alloc = alloc;
+    c->clogging_input_filters = 0;
 
     return c;
 }
Index: modules/http/http_core.c
===================================================================
--- modules/http/http_core.c    (revision 545614)
+++ modules/http/http_core.c    (working copy)
@@ -119,11 +119,17 @@
     return DEFAULT_HTTP_PORT;
 }
 
+static int ap_process_http_connection(conn_rec *c);
+
 static int ap_process_http_async_connection(conn_rec *c)
 {
     request_rec *r;
     conn_state_t *cs = c->cs;
 
+    if (c->clogging_input_filters) {
+        return ap_process_http_connection(c);
+    }
+    
     AP_DEBUG_ASSERT(cs->state == CONN_STATE_READ_REQUEST_LINE);
 
     while (cs->state == CONN_STATE_READ_REQUEST_LINE) {
Index: modules/ssl/ssl_engine_io.c
===================================================================
--- modules/ssl/ssl_engine_io.c (revision 545614)
+++ modules/ssl/ssl_engine_io.c (working copy)
@@ -1665,6 +1665,9 @@
     filter_ctx->pbioWrite       = BIO_new(&bio_filter_out_method);
     filter_ctx->pbioWrite->ptr  = (void *)bio_filter_out_ctx_new(filter_ctx, 
c);
 
+    /* We insert a clogging input filter. Let the core know. */
+    c->clogging_input_filters = 1;
+    
     ssl_io_input_add_filter(filter_ctx, c, ssl);
 
     SSL_set_bio(ssl, filter_ctx->pbioRead, filter_ctx->pbioWrite);
Index: include/httpd.h
===================================================================
--- include/httpd.h     (revision 545614)
+++ include/httpd.h     (working copy)
@@ -1081,6 +1081,11 @@
     int data_in_input_filters;
     /** Is there data pending in the output filters? */
     int data_in_output_filters;
+    
+    /** Are there any filters that clogg/buffer the input stream, breaking
+     *  the event mpm.
+     */
+    int clogging_input_filters;
 };
 
 /**