From 5fbc220862fc7a53a0455ccd2d96c82141e222d4 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Sat, 9 May 2020 10:59:19 -0700 Subject: [PATCH] tools/libpf: Add offsetof/container_of macro in bpf_helpers.h These two helpers will be used later in bpf_iter bpf program bpf_iter_netlink.c. Put them in bpf_helpers.h since they could be useful in other cases. Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200509175919.2477104-1-yhs@fb.com --- tools/lib/bpf/bpf_helpers.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index da00b87aa199..f67dce2af802 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -36,6 +36,20 @@ #define __weak __attribute__((weak)) #endif +/* + * Helper macro to manipulate data structures + */ +#ifndef offsetof +#define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER) +#endif +#ifndef container_of +#define container_of(ptr, type, member) \ + ({ \ + void *__mptr = (void *)(ptr); \ + ((type *)(__mptr - offsetof(type, member))); \ + }) +#endif + /* * Helper structure used by eBPF C program * to describe BPF map attributes to libbpf loader