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Re: misc/sys/xattr.h: guard against linux uapi header inclusion
- From: Serge Hallyn <serge dot hallyn at ubuntu dot com>
- To: Allan McRae <allan at archlinux dot org>
- Cc: OndÅej BÃlka <neleai at seznam dot cz>, libc-alpha at sourceware dot org, "Andrew G. Morgan" <morgan at kernel dot org>, serge dot hallyn at ubuntu dot com
- Date: Thu, 20 Mar 2014 21:26:52 -0500
- Subject: Re: misc/sys/xattr.h: guard against linux uapi header inclusion
- Authentication-results: sourceware.org; auth=none
- References: <20140311041707 dot GA6064 at sergelap> <20140318132710 dot GA9737 at domone dot podge> <532B7DBB dot 6040804 at archlinux dot org>
Quoting Allan McRae (allan@archlinux.org):
> On 18/03/14 23:27, OndÅej BÃlka wrote:
> > On Mon, Mar 10, 2014 at 11:17:07PM -0500, Serge Hallyn wrote:
> >> If the glibc xattr.h header is included after the uapi header,
> >> compilation fails due to an enum re-using a #define from the
> >> uapi header. Protect against this by guarding the define and
> >> enum inclusions against each other.
> >>
> >> (A corresponding kernel patch has been sent here:
> >> http://lkml.org/lkml/2014/3/7/331 )
> >>
> >> (See https://lists.debian.org/debian-glibc/2014/03/msg00029.html
> >> and https://sourceware.org/glibc/wiki/Synchronizing_Headers
> >> for more information.)
> >>
> >> Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
> >>
> > Looks ok, I commited that with appropriate ChangeLog.
> >
>
> Has the kernel patch been reviewed? This should not have been committed
Nope, no feedback yet.
> before there was agreement between both parties that the patches were good.
>
> The kernel patch in the link looks wrong to me. The define
> __UAPI_DEF_XATTR is set to 0 whenever any glibc header is included, not
> just sys/xattr.h. It should be wrapped in "#ifdef _SYS_XATTR_H".
Good point, thanks! I missed that part of the network patch I
was emulating. I'll fix it up, resend, and cc: akpm.
> The glibc patch is fine, but pointless until is the kernel patch is
> accepted.
> >> ---
> >> misc/sys/xattr.h | 2 ++
> >> 1 file changed, 2 insertions(+)
> >>
> >> diff --git a/misc/sys/xattr.h b/misc/sys/xattr.h
> >> index 929cd87..796df90 100644
> >> --- a/misc/sys/xattr.h
> >> +++ b/misc/sys/xattr.h
> >> @@ -26,6 +26,7 @@ __BEGIN_DECLS
> >>
> >> /* The following constants should be used for the fifth parameter of
> >> `*setxattr'. */
> >> +#ifndef __USE_KERNEL_XATTR_DEFS
> >> enum
> >> {
> >> XATTR_CREATE = 1, /* set value, fail if attr already exists. */
> >> @@ -33,6 +34,7 @@ enum
> >> XATTR_REPLACE = 2 /* set value, fail if attr does not exist. */
> >> #define XATTR_REPLACE XATTR_REPLACE
> >> };
> >> +#endif
> >>
> >> /* Set the attribute NAME of the file pointed to by PATH to VALUE (which
> >> is SIZE bytes long). Return 0 on success, -1 for errors. */
> >
> >
> >
>