Re: [Qemu-devel] [PATCH] 9pfs: include <linux/limits.h> for XATTR_SIZE_MAX

[Patrick Steinhardt <ps@pks.im>]

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On Fri, Jul 28, 2017 at 02:20:49PM -0300, Philippe Mathieu-Daudé wrote:
> > On Mon, Jun 26, 2017 at 12:20 PM, Patrick Steinhardt <ps@pks.im> wrote:
> >> The function `v9fs_xattrcreate` makes use of the define `XATTR_SIZE_MAX`
> >> to reject attempts of creating xattrs with an invalid size, which is
> >> defined in <linux/limits.h>. On glibc-based systems, this header is
> >> indirectly included via <limits.h>, <bits/posix1_lim.h>,
> >> <bitts/local_lim.h>, but on other platforms this is not guaranteed due
> >> to not being part of the POSIX standard. One examples are systems based
> >> on musl libc, which do not include the <linux/limits.h> indirectly,
> >> which leads to `XATTR_SIZE_MAX` being undefined.
> >>
> >> Fix this error by directly include <linux/limits.h>. As the 9P fs code
> >> is being Linux-based either way, we can simply do so without breaking
> >> other platforms. This enables building 9pfs on musl-based systems.
> >>
> >> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> > Reviewed-by: Alistair Francis <alistair.francis@xilinx.com>
> >> ---
> >>   hw/9pfs/9p.c | 1 +
> >>   1 file changed, 1 insertion(+)
> >>
> >> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> >> index 96d2683348..48cd558e96 100644
> >> --- a/hw/9pfs/9p.c
> >> +++ b/hw/9pfs/9p.c
> >> @@ -13,6 +13,7 @@
> >>
> >>   #include "qemu/osdep.h"
> >>   #include <glib/gprintf.h>
> 
> This is likely to break on BSD, but now than patchew has a NetBSD job 
> you can trigger a build RESENDing this patch.
> 
> This should probably work:
> 
> #ifdef __linux__
> 
> >> +#include <linux/limits.h>
> 
> #endif
> 
> >>   #include "hw/virtio/virtio.h"
> >>   #include "qapi/error.h"
> >>   #include "qemu/error-report.h"
> >> --
> >> 2.13.2
> 
> Regards,
> 
> Phil.

Thanks for the feedback! Is this really relevant in this context,
though? Both 9p-local.c and 9p-handle.c already include linux
headers, especially <linux/fs.h> is included without any ifdef
around. As such, I simply assumed that this code is being built
on Linux systems, only.

Regards
Patrick

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