SSL: use of the SSL_OP_IGNORE_UNEXPECTED_EOF option. A new behaviour was introduced in OpenSSL 1.1.1e, when a peer does not send close_notify before closing the connection. Previously, it was to return SSL_ERROR_SYSCALL with errno 0, known since at least OpenSSL 0.9.7, and is handled gracefully in nginx. Now it returns SSL_ERROR_SSL with a distinct reason SSL_R_UNEXPECTED_EOF_WHILE_READING ("unexpected eof while reading"). This leads to critical errors seen in nginx within various routines such as SSL_do_handshake(), SSL_read(), SSL_shutdown(). The behaviour was restored in OpenSSL 1.1.1f, but presents in OpenSSL 3.0 by default. Use of the SSL_OP_IGNORE_UNEXPECTED_EOF option added in OpenSSL 3.0 allows to set a compatible behaviour to return SSL_ERROR_ZERO_RETURN: https://git.openssl.org/?p=openssl.git;a=commitdiff;h=09b90e0 See for additional details: https://github.com/openssl/openssl/issues/11381

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


echo $ngx_n "checking for system byte ordering ...$ngx_c"

cat << END >> $NGX_AUTOCONF_ERR

----------------------------------------
checking for system byte ordering

END


cat << END > $NGX_AUTOTEST.c

int main(void) {
    int i = 0x11223344;
    char *p;

    p = (char *) &i;
    if (*p == 0x44) return 0;
    return 1;
}

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
    if $NGX_AUTOTEST >/dev/null 2>&1; then
        echo " little endian"
        have=NGX_HAVE_LITTLE_ENDIAN . auto/have
    else
        echo " big endian"
    fi

    rm -rf $NGX_AUTOTEST*

else
    rm -rf $NGX_AUTOTEST*

    echo
    echo "$0: error: cannot detect system byte ordering"
    exit 1
fi