On Tue, Dec 20, 2022 at 7:55 PM Leo Yan <leo.yan@xxxxxxxxxx> wrote: > > On Tue, Dec 20, 2022 at 04:13:13PM -0800, Andrii Nakryiko wrote: > > [...] > > > > > > > @@ -990,6 +990,7 @@ static struct btf *btf_parse_elf(const char *path, struct btf *base_btf, > > > > > > err = 0; > > > > > > > > > > > > if (!btf_data) { > > > > > > + pr_warn("failed to find '%s' ELF section in %s\n", BTF_ELF_SEC, path); > > > > > > err = -ENOENT; > > > > > > btf_parse_elf() returns -ENOENT when ELF file doesn't contain BTF > > > section, therefore, bpftool dumps error string "No such file or > > > directory". It's confused that actually vmlinux is existed. > > > > > > I am wondering if we can use error -LIBBPF_ERRNO__FORMAT (or any > > > better choice?) to replace -ENOENT at here, this can avoid bpftool to > > > outputs "No such file or directory" in this case. > > > > The only really meaningful error code would be -ESRCH, which > > strerror() will translate to "No such process", which is also > > completely confusing. > > Or maybe -ENODATA (No data available) is a better choice? -ENODATA sounds good to me, yep. > > Thanks, > Leo > > > In general, I always found these strerror() messages extremely > > unhelpful and confusing. I wonder if we should make an effort to > > actually emit symbolic names of errors instead (literally, "-ENOENT" > > in this case). This is all tooling for engineers, I find -ENOENT or > > -ESRCH much more meaningful as an error message, compared to "No such > > file" seemingly human-readable interpretation. > > > > Quenting, what do you think about the above proposal for bpftool? We > > can have some libbpf helper internally and do it in libbpf error > > messages as well and just reuse the logic in bpftool, perhaps? > > > > Anyways, I've applied this patch set to bpf-next. Thanks.