lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Sat, 18 Jul 2020 20:52:27 -0700 From: Andrii Nakryiko <andrii.nakryiko@...il.com> To: Ian Rogers <irogers@...gle.com> Cc: Alexei Starovoitov <ast@...nel.org>, Daniel Borkmann <daniel@...earbox.net>, Martin KaFai Lau <kafai@...com>, Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>, Andrii Nakryiko <andriin@...com>, John Fastabend <john.fastabend@...il.com>, KP Singh <kpsingh@...omium.org>, Networking <netdev@...r.kernel.org>, bpf <bpf@...r.kernel.org>, open list <linux-kernel@...r.kernel.org>, Stanislav Fomichev <sdf@...gle.com> Subject: Re: [PATCH] libbpf bpf_helpers: Use __builtin_offsetof for offsetof if available On Fri, Jul 17, 2020 at 12:24 AM Ian Rogers <irogers@...gle.com> wrote: > > The non-builtin route for offsetof has a dependency on size_t from > stdlib.h/stdint.h that is undeclared and may break targets. > The offsetof macro in bpf_helpers may disable the same macro in other > headers that have a #ifdef offsetof guard. Rather than add additional > dependencies improve the offsetof macro declared here to use the > builtin if available. > > Signed-off-by: Ian Rogers <irogers@...gle.com> > --- > tools/lib/bpf/bpf_helpers.h | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h > index a510d8ed716f..ed2ac74fc515 100644 > --- a/tools/lib/bpf/bpf_helpers.h > +++ b/tools/lib/bpf/bpf_helpers.h > @@ -40,8 +40,12 @@ > * Helper macro to manipulate data structures > */ > #ifndef offsetof > +#if __has_builtin(__builtin_offsetof) > +#define offsetof(TYPE, MEMBER) __builtin_offsetof(TYPE, MEMBER) > +#else > #define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER) Let's either always use __builtin_offsetof (as Yonghong mentioned, it should always be available on relevant LLVM versions). Or instead of size_t, just cast to (unsigned long), I think it will have absolutely the same effect as size_t casting? > #endif > +#endif > #ifndef container_of > #define container_of(ptr, type, member) \ > ({ \ > -- > 2.28.0.rc0.105.gf9edc3c819-goog >
Powered by blists - more mailing lists