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.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


echo $ngx_n "checking for uintptr_t ...$ngx_c"

cat << END >> $NGX_AUTOCONF_ERR

----------------------------------------
checking for uintptr_t

END

found=no

cat << END > $NGX_AUTOTEST.c

#include <sys/types.h>
$NGX_INCLUDE_INTTYPES_H

int main(void) {
    uintptr_t i = 0;
    return (int) i;
}

END

ngx_test="$CC $CC_TEST_FLAGS $CC_AUX_FLAGS \
          -o $NGX_AUTOTEST $NGX_AUTOTEST.c $NGX_LD_OPT"

eval "$ngx_test >> $NGX_AUTOCONF_ERR 2>&1"

if [ -x $NGX_AUTOTEST ]; then
    echo " uintptr_t found"
    found=yes
else
    echo $ngx_n " uintptr_t not found" $ngx_c
fi

rm -rf $NGX_AUTOTEST*


if [ $found = no ]; then
    found="uint`expr 8 \* $ngx_ptr_size`_t"
    echo ", $found used"

    echo "typedef $found  uintptr_t;"                   >> $NGX_AUTO_CONFIG_H
    echo "typedef $found  intptr_t;" | sed -e 's/u//g'  >> $NGX_AUTO_CONFIG_H
fi