Re: [PATCH] 9pfs: fix dead code in qemu_open_flags_tostr()

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 10/2/25 15:33, Christian Schoenebeck wrote:
> Coverity scan complained about expression "|LARGEFILE" to be non reachable
> and the detailed Coverity report claims O_LARGEFILE was zero. I can't
> reproduce this here, but I assume that means there are at least some
> system(s) which define O_LARGEFILE as zero.

Is O_LARGEFILE a Linux-ism?

Commit 67b915a5dd5 ("win32 port (initial patch by kazu)") started to
define it to 0 on 32-bit Windows. It isn't defined on my 64-bit Darwin,
and apparently nor on other BSDs.

> This is not really an issue, but to silence this Coverity warning, add a
> preprocessor wrapper that checks for O_LARGEFILE being non-zero for this
> overall expression. The 'defined(O_LARGEFILE)' check is not necessary,
> but it makes it more clear that we really want to check for the value of
> O_LARGEFILE, not just whether the macro was defined.
> 
> Fixes: 9a0dd4b3
> Resolves: Coverity CID 1591178
> Reported-by: Coverity Scan
> Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
> ---
>   hw/9pfs/9p-util-generic.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/hw/9pfs/9p-util-generic.c b/hw/9pfs/9p-util-generic.c
> index 4c1e9c887d..02e359f17b 100644
> --- a/hw/9pfs/9p-util-generic.c
> +++ b/hw/9pfs/9p-util-generic.c
> @@ -19,7 +19,9 @@ char *qemu_open_flags_tostr(int flags)
>           #ifdef O_DIRECT
>           (flags & O_DIRECT) ? "|DIRECT" : "",
>           #endif
> +        #if defined(O_LARGEFILE) && O_LARGEFILE != 0
>           (flags & O_LARGEFILE) ? "|LARGEFILE" : "",
> +        #endif
>           (flags & O_DIRECTORY) ? "|DIRECTORY" : "",
>           (flags & O_NOFOLLOW) ? "|NOFOLLOW" : "",
>           #ifdef O_NOATIME