From 12ef5634a855eb642b4d28781526fbd830aa7f7a Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 29 May 2019 10:36:05 -0700 Subject: [PATCH] libbpf: simplify endianness check Rewrite endianness check to use "more canonical" way, using compiler-defined macros, similar to few other places in libbpf. It also is more obvious and shorter. Acked-by: Song Liu Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann --- tools/lib/bpf/libbpf.c | 35 +++++++++++------------------------ 1 file changed, 11 insertions(+), 24 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 40690b7e500e..fb296eadc3f2 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -607,31 +607,18 @@ errout: return err; } -static int -bpf_object__check_endianness(struct bpf_object *obj) +static int bpf_object__check_endianness(struct bpf_object *obj) { - static unsigned int const endian = 1; - - switch (obj->efile.ehdr.e_ident[EI_DATA]) { - case ELFDATA2LSB: - /* We are big endian, BPF obj is little endian. */ - if (*(unsigned char const *)&endian != 1) - goto mismatch; - break; - - case ELFDATA2MSB: - /* We are little endian, BPF obj is big endian. */ - if (*(unsigned char const *)&endian != 0) - goto mismatch; - break; - default: - return -LIBBPF_ERRNO__ENDIAN; - } - - return 0; - -mismatch: - pr_warning("Error: endianness mismatch.\n"); +#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ + if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2LSB) + return 0; +#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ + if (obj->efile.ehdr.e_ident[EI_DATA] == ELFDATA2MSB) + return 0; +#else +# error "Unrecognized __BYTE_ORDER__" +#endif + pr_warning("endianness mismatch.\n"); return -LIBBPF_ERRNO__ENDIAN; }