aio/unix: Use signal.sival which is standard

[Maxim Dounin]

Hello!

On Thu, Jan 17, 2019 at 01:29:56PM +0300, Sergey Kandaurov wrote:

> 
> 
> > On 17 Jan 2019, at 08:43, Sepherosa Ziehau <sepherosa at gmail.com> wrote:
> > 
> > What's the preferred way to handle this?  I am not sure whether you
> > guys allow __FreeBSD_version testing etc.
> > 
> 
> This could be solved with autotests.

As long as we only care about different FreeBSD versions, this 
might as well be an auto/os/freebsd test based on $version, or 
just a define based on __FreeBSD_version in 
src/os/unix/ngx_freebsd_config.h.

> # HG changeset patch
> # User Sergey Kandaurov <pluknet at nginx.com>
> # Date 1547720890 0
> #      Thu Jan 17 10:28:10 2019 +0000
> # Node ID d28513cd71bce227b4e159b7a3f518aa504232f0
> # Parent  6d15e452fa2eaf19408e24a0d0fcc3a31344a289
> Fixed portability issues with union sigval.
> 
> The sival_ptr field is now preferably used.
> 
> diff --git a/auto/unix b/auto/unix
> --- a/auto/unix
> +++ b/auto/unix
> @@ -523,6 +523,7 @@ if [ $NGX_FILE_AIO = YES ]; then
>      ngx_feature_libs=
>      ngx_feature_test="struct aiocb  iocb;
>                        iocb.aio_sigevent.sigev_notify = SIGEV_KEVENT;
> +                      iocb.aio_sigevent.sigev_value.sival_ptr = NULL;
>                        (void) aio_read(&iocb)"
>      . auto/feature
>  
> @@ -532,6 +533,22 @@ if [ $NGX_FILE_AIO = YES ]; then
>  
>      if [ $ngx_found = no ]; then
>  
> +        ngx_feature="kqueue AIO support (legacy)"
> +        ngx_feature_name="NGX_HAVE_FILE_AIO_LEGACY"
> +        ngx_feature_test="struct aiocb  iocb;
> +                          iocb.aio_sigevent.sigev_notify = SIGEV_KEVENT;
> +                          iocb.aio_sigevent.sigev_value.sigval_ptr = NULL;
> +                          (void) aio_read(&iocb)"
> +        . auto/feature

Note that this will test for "kqueue AIO support (legacy)" on each 
Linux build with aio.

> +
> +        if [ $ngx_found = yes ]; then
> +            CORE_SRCS="$CORE_SRCS $FILE_AIO_SRCS"
> +            have=NGX_HAVE_FILE_AIO . auto/have
> +        fi
> +    fi
> +
> +    if [ $ngx_found = no ]; then
> +
>          ngx_feature="Linux AIO support"
>          ngx_feature_name="NGX_HAVE_FILE_AIO"
>          ngx_feature_run=no
> diff --git a/src/os/unix/ngx_file_aio_read.c b/src/os/unix/ngx_file_aio_read.c
> --- a/src/os/unix/ngx_file_aio_read.c
> +++ b/src/os/unix/ngx_file_aio_read.c
> @@ -110,8 +110,12 @@ ngx_file_aio_read(ngx_file_t *file, u_ch
>  #if (NGX_HAVE_KQUEUE)
>      aio->aiocb.aio_sigevent.sigev_notify_kqueue = ngx_kqueue;
>      aio->aiocb.aio_sigevent.sigev_notify = SIGEV_KEVENT;
> +#if !(NGX_HAVE_FILE_AIO_LEGACY)
> +    aio->aiocb.aio_sigevent.sigev_value.sival_ptr = ev;
> +#else
>      aio->aiocb.aio_sigevent.sigev_value.sigval_ptr = ev;
>  #endif
> +#endif
>      ev->handler = ngx_file_aio_event_handler;
>  
>      n = aio_read(&aio->aiocb);

A simplier solution might be to always use sival_ptr, and define 
it to sigval_ptr on old FreeBSDs.

Alternatively, we can consider dropping file AIO support for these 
old FreeBSD versions.  This shouldn't be a big deal as this is an 
optional feature which is not enabled by default.

-- 
Maxim Dounin
http://mdounin.ru/