view auto/types/sizeof @ 8018:5119c8150478

Fixed runtime handling of systems without EPOLLRDHUP support. In 7583:efd71d49bde0 (nginx 1.17.5) along with introduction of the ioctl(FIONREAD) support proper handling of systems without EPOLLRDHUP support in the kernel (but with EPOLLRDHUP in headers) was broken. Before the change, rev->available was never set to 0 unless ngx_use_epoll_rdhup was also set (that is, runtime test for EPOLLRDHUP introduced in 6536:f7849bfb6d21 succeeded). After the change, rev->available might reach 0 on systems without runtime EPOLLRDHUP support, stopping further reading in ngx_readv_chain() and ngx_unix_recv(). And, if EOF happened to be already reported along with the last event, it is not reported again by epoll_wait(), leading to connection hangs and timeouts on such systems. This affects Linux kernels before 2.6.17 if nginx was compiled with newer headers, and, more importantly, emulation layers, such as DigitalOcean's App Platform's / gVisor's epoll emulation layer. Fix is to explicitly check ngx_use_epoll_rdhup before the corresponding rev->pending_eof tests in ngx_readv_chain() and ngx_unix_recv().
author Marcus Ball <marcus.ball@live.com>
date Mon, 30 May 2022 02:38:07 +0300
parents e3faa5fb7772
children
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# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


echo $ngx_n "checking for $ngx_type size ...$ngx_c"

cat << END >> $NGX_AUTOCONF_ERR

----------------------------------------
checking for $ngx_type size

END

ngx_size=

cat << END > $NGX_AUTOTEST.c

#include <sys/types.h>
#include <sys/time.h>
$NGX_INCLUDE_UNISTD_H
#include <signal.h>
#include <stdio.h>
#include <sys/resource.h>
$NGX_INCLUDE_INTTYPES_H
$NGX_INCLUDE_AUTO_CONFIG_H

int main(void) {
    printf("%d", (int) sizeof($ngx_type));
    return 0;
}

END


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

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


if [ -x $NGX_AUTOTEST ]; then
    ngx_size=`$NGX_AUTOTEST`
    echo " $ngx_size bytes"
fi


case $ngx_size in
    4)
        ngx_max_value=2147483647
        ngx_max_len='(sizeof("-2147483648") - 1)'
    ;;

    8)
        ngx_max_value=9223372036854775807LL
        ngx_max_len='(sizeof("-9223372036854775808") - 1)'
    ;;

    *)
        echo
        echo "$0: error: can not detect $ngx_type size"

        echo "----------"    >> $NGX_AUTOCONF_ERR
        cat $NGX_AUTOTEST.c  >> $NGX_AUTOCONF_ERR
        echo "----------"    >> $NGX_AUTOCONF_ERR
        echo $ngx_test       >> $NGX_AUTOCONF_ERR
        echo "----------"    >> $NGX_AUTOCONF_ERR

        rm -rf $NGX_AUTOTEST*

        exit 1
esac


rm -rf $NGX_AUTOTEST*