The ngx_http_upstream_process_upgraded() did not handle c->close request, and upgraded connections do not use the write filter. As a result, worker_shutdown_timeout did not affect upgraded connections (ticket #1419). Fix is to handle c->close in the ngx_http_request_handler() function, thus covering most of the possible cases in http handling. Additionally, mail proxying did not handle neither c->close nor c->error, and thus worker_shutdown_timeout did not work for mail connections. Fix is to add c->close handling to ngx_mail_proxy_handler(). Also, added explicit handling of c->close to stream proxy, ngx_stream_proxy_process_connection(). This improves worker_shutdown_timeout handling in stream, it will no longer wait for some data being transferred in a connection before closing it, and will also provide appropriate logging at the "info" level.
A zlib variant from Intel as available from https://github.com/jtkukunas/zlib uses 64K hash instead of scaling it from the specified memory level, and also uses 16-byte padding in one of the window-sized memory buffers, and can force window bits to 13 if compression level is set to 1 and appropriate compile options are used. As a result, nginx complained with "gzip filter failed to use preallocated memory" alerts. This change improves deflate_state allocation detection by testing that items is 1 (deflate_state is the only allocation where items is 1). Additionally, on first failure to use preallocated memory we now assume that we are working with the Intel's modified zlib, and switch to using appropriate preallocations. If this does not help, we complain with the usual alerts. Previous version of this patch was published at http://mailman.nginx.org/pipermail/nginx/2014-July/044568.html. The zlib variant in question is used by default in ClearLinux from Intel, see http://mailman.nginx.org/pipermail/nginx-ru/2017-October/060421.html, http://mailman.nginx.org/pipermail/nginx-ru/2017-November/060544.html.
If parameters were specified in xslt_stylesheet without variables, any request except the first would cause an internal server error.
Previously, nginx failed to move buffer position when parsing an incomplete record header, and due to this wasn't be able to continue parsing once remaining bytes of the record header were received. This can affect response header parsing, potentially generating spurious errors like "upstream sent unexpected FastCGI request id high byte: 1 while reading response header from upstream". While this is very unlikely, since usually record headers are written in a single buffer, this still can happen in real life, for example, if a record header will be split across two TCP packets and the second packet will be delayed. This does not affect non-buffered response body proxying, due to "buf->pos = buf->last;" at the start of the ngx_http_fastcgi_non_buffered_filter() function. Also this does not affect buffered response body proxying, as each input buffer is only passed to the filter once.
In particular, if ngx_http_postpone_filter_add() fails in ngx_chain_add_copy(), the output chain of the postponed request was left in an invalid state.
Upgrading an upstream connection is usually followed by reading from the client which a subrequest is not allowed to do. Moreover, accessing the header_in request field while processing upgraded connection ends up with a null pointer dereference since the header_in buffer is only created for the the main request.
If proxy_next_upstream includes http_503/http_504, and upstream returns 503/504, $upstream_status converted this to 502 for any values except the last one.
The NGX_DONE value returned from ngx_http_upstream_cache_send() indicates that upstream was already finalized in ngx_http_upstream_process_headers(). It was treated as a generic error which resulted in duplicate finalization. Handled NGX_HTTP_UPSTREAM_INVALID_HEADER from ngx_http_upstream_cache_send(). Previously, it could return within ngx_http_upstream_finalize_request(), and since it's below NGX_HTTP_SPECIAL_RESPONSE, a client connection could stuck.
When parsing of headers in a cache file fails, already parsed headers need to be cleared, and protocol state needs to be reinitialized. To do so, u->request_sent is now set to ensure ngx_http_upstream_reinit() will be called. This change complements improvements in 46ddff109e72.