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 <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200509175919.2477104-1-yhs@fb.com
This commit is contained in:
Yonghong Song 2020-05-09 10:59:19 -07:00 committed by Alexei Starovoitov
parent c09add2fbc
commit 5fbc220862

View File

@ -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