[nginx] SSL: restore handlers after blocking.

[Maxim Dounin]

details:   http://hg.nginx.org/nginx/rev/87d2ea860f38
branches:  
changeset: 7353:87d2ea860f38
user:      Maxim Dounin <mdounin at mdounin.ru>
date:      Mon Sep 10 18:57:39 2018 +0300
description:
SSL: restore handlers after blocking.

It is possible that after SSL_read() will return SSL_ERROR_WANT_WRITE,
further calls will return SSL_ERROR_WANT_READ without reading any
application data.  We have to call ngx_handle_write_event() and
switch back to normal write handling much like we do if there are some
application data, or the write there will be reported again and again.

Similarly, we have to switch back to normal read handling if there
is saved read handler and SSL_write() returns SSL_ERROR_WANT_WRITE.

diffstat:

 src/event/ngx_event_openssl.c |  28 ++++++++++++++++++++++++++++
 1 files changed, 28 insertions(+), 0 deletions(-)

diffs (45 lines):

diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -1675,6 +1675,20 @@ ngx_ssl_handle_recv(ngx_connection_t *c,
     ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL_get_error: %d", sslerr);
 
     if (sslerr == SSL_ERROR_WANT_READ) {
+
+        if (c->ssl->saved_write_handler) {
+
+            c->write->handler = c->ssl->saved_write_handler;
+            c->ssl->saved_write_handler = NULL;
+            c->write->ready = 1;
+
+            if (ngx_handle_write_event(c->write, 0) != NGX_OK) {
+                return NGX_ERROR;
+            }
+
+            ngx_post_event(c->write, &ngx_posted_events);
+        }
+
         c->read->ready = 0;
         return NGX_AGAIN;
     }
@@ -1934,6 +1948,20 @@ ngx_ssl_write(ngx_connection_t *c, u_cha
     ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0, "SSL_get_error: %d", sslerr);
 
     if (sslerr == SSL_ERROR_WANT_WRITE) {
+
+        if (c->ssl->saved_read_handler) {
+
+            c->read->handler = c->ssl->saved_read_handler;
+            c->ssl->saved_read_handler = NULL;
+            c->read->ready = 1;
+
+            if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+                return NGX_ERROR;
+            }
+
+            ngx_post_event(c->read, &ngx_posted_events);
+        }
+
         c->write->ready = 0;
         return NGX_AGAIN;
     }