Fixed sendfile in threads (or with aio preload) and subrequests. If sendfile in threads is used, it is possible that multiple subrequests will trigger multiple ngx_linux_sendfile_thread() calls, as operations are only serialized in output chain based on r->aio, that is, on subrequest level. This resulted in "task #N already active" alerts, in particular, when running proxy_store.t with "aio threads; sendfile on;". Fix is to tolerate duplicate calls, with an additional safety check that the file is the same as previously used. The same problem also affects "aio on; sendfile on;" on FreeBSD (previously known as "aio sendfile;"), where aio->preload_handler() could be called multiple times due to similar reasons, resulting in "second aio post" alerts. Fix is the same as well. It is also believed that similar problems can arise if a filter calls the next body filter multiple times for some reason. These are mostly theoretical though.

# 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() {
    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