Mercurial > hg > nginx
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Events: improved error event handling for UDP sockets.
Normally, the epoll module calls the read and write handlers depending
on whether EPOLLIN and EPOLLOUT are reported by epoll_wait(). No error
processing is done in the module, the handlers are expected to get an
error when doing I/O.
If an error event is reported without EPOLLIN and EPOLLOUT, the module
set both EPOLLIN and EPOLLOUT to ensure the error event is handled at
least in one active handler.
This works well unless the error is delivered along with only one of
EPOLLIN or EPOLLOUT, and the corresponding handler does not do any I/O.
For example, it happened when getting EPOLLERR|EPOLLOUT from
epoll_wait() upon receiving "ICMP port unreachable" while proxying UDP.
As the write handler had nothing to send it was not able to detect and
log an error, and did not switch to the next upstream.
The fix is to unconditionally set EPOLLIN and EPOLLOUT in case of an
error event. In the aforementioned case, this causes the read handler
to be called which does recv() and detects an error.
In addition to the epoll module, analogous changes were made in
devpoll/eventport/poll.
| author | Dmitry Volyntsev <xeioex@nginx.com> |
|---|---|
| date | Mon, 21 Nov 2016 16:03:42 +0300 |
| parents | 9eefb38f0005 |
| children | 0b5f12d5c531 |
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# Copyright (C) Igor Sysoev # Copyright (C) Nginx, Inc. echo echo "Configuration summary" if [ $USE_THREADS = YES ]; then echo " + using threads" fi if [ $USE_PCRE = DISABLED ]; then echo " + PCRE library is disabled" else case $PCRE in YES) echo " + using system PCRE library" ;; NONE) echo " + PCRE library is not used" ;; *) echo " + using PCRE library: $PCRE" ;; esac fi case $OPENSSL in YES) echo " + using system OpenSSL library" ;; NONE) echo " + OpenSSL library is not used" ;; *) echo " + using OpenSSL library: $OPENSSL" ;; esac case $ZLIB in YES) echo " + using system zlib library" ;; NONE) echo " + zlib library is not used" ;; *) echo " + using zlib library: $ZLIB" ;; esac case $NGX_LIBATOMIC in YES) echo " + using system libatomic_ops library" ;; NO) ;; # not used *) echo " + using libatomic_ops library: $NGX_LIBATOMIC" ;; esac echo cat << END nginx path prefix: "$NGX_PREFIX" nginx binary file: "$NGX_SBIN_PATH" nginx modules path: "$NGX_MODULES_PATH" nginx configuration prefix: "$NGX_CONF_PREFIX" nginx configuration file: "$NGX_CONF_PATH" nginx pid file: "$NGX_PID_PATH" END if test -n "$NGX_ERROR_LOG_PATH"; then echo " nginx error log file: \"$NGX_ERROR_LOG_PATH\"" else echo " nginx logs errors to stderr" fi cat << END nginx http access log file: "$NGX_HTTP_LOG_PATH" nginx http client request body temporary files: "$NGX_HTTP_CLIENT_TEMP_PATH" END if [ $HTTP_PROXY = YES ]; then echo " nginx http proxy temporary files: \"$NGX_HTTP_PROXY_TEMP_PATH\"" fi if [ $HTTP_FASTCGI = YES ]; then echo " nginx http fastcgi temporary files: \"$NGX_HTTP_FASTCGI_TEMP_PATH\"" fi if [ $HTTP_UWSGI = YES ]; then echo " nginx http uwsgi temporary files: \"$NGX_HTTP_UWSGI_TEMP_PATH\"" fi if [ $HTTP_SCGI = YES ]; then echo " nginx http scgi temporary files: \"$NGX_HTTP_SCGI_TEMP_PATH\"" fi echo "$NGX_POST_CONF_MSG"