On Wed, Oct 20, 2021 at 11:12 AM Andrii Nakryiko
<andrii.nakryiko@xxxxxxxxx> wrote:
>
> On Tue, Oct 12, 2021 at 9:15 AM Stanislav Fomichev <sdf@xxxxxxxxxx> wrote:
> >
> > Otherwise, attaching with bpftool doesn't work with strict section names.
> >
> > Also, switch to libbpf strict mode to use the latest conventions
> > (note, I don't think we have any cli api guarantees?).
> >
> > Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
> > ---
> > tools/bpf/bpftool/main.c | 4 ++++
> > tools/bpf/bpftool/prog.c | 15 +--------------
> > 2 files changed, 5 insertions(+), 14 deletions(-)
> >
> > diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
> > index 02eaaf065f65..8223bac1e401 100644
> > --- a/tools/bpf/bpftool/main.c
> > +++ b/tools/bpf/bpftool/main.c
> > @@ -409,6 +409,10 @@ int main(int argc, char **argv)
> > block_mount = false;
> > bin_name = argv[0];
> >
> > + ret = libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
>
> Quentin, any concerns about turning strict mode for bpftool? Either
> way we should audit bpftool code to ensure that at least error
> handling is done properly (see my comments on Dave's patch set about
> == -1 checks).
>
> > + if (ret)
> > + p_err("failed to enable libbpf strict mode: %d", ret);
> > +
> > hash_init(prog_table.table);
> > hash_init(map_table.table);
> > hash_init(link_table.table);
> > diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
> > index 277d51c4c5d9..17505dc1243e 100644
> > --- a/tools/bpf/bpftool/prog.c
> > +++ b/tools/bpf/bpftool/prog.c
> > @@ -1396,8 +1396,6 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> >
> > while (argc) {
> > if (is_prefix(*argv, "type")) {
> > - char *type;
> > -
> > NEXT_ARG();
> >
> > if (common_prog_type != BPF_PROG_TYPE_UNSPEC) {
> > @@ -1407,19 +1405,8 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> > if (!REQ_ARGS(1))
> > goto err_free_reuse_maps;
> >
> > - /* Put a '/' at the end of type to appease libbpf */
> > - type = malloc(strlen(*argv) + 2);
> > - if (!type) {
> > - p_err("mem alloc failed");
> > - goto err_free_reuse_maps;
> > - }
> > - *type = 0;
> > - strcat(type, *argv);
> > - strcat(type, "/");
> > -
> > - err = get_prog_type_by_name(type, &common_prog_type,
> > + err = get_prog_type_by_name(*argv, &common_prog_type,
> > &expected_attach_type);
>
> Question not specifically to Stanislav, but anyone who's using bpftool
> to load programs. Do we need to support program type overrides? Libbpf
> has been inferring the program type for a long time now, are there
> realistic use cases where this override logic is necessary? I see
> there is bpf_object__for_each_program() loop down the code, it
> essentially repeats what libbpf is already doing on
> bpf_object__open(), why keep the duplicated logic?
>
> libbpf_prog_type_by_name() is also a bad idea (IMO) and I'd like to
> get rid of that in libbpf 1.0, so if we can stop using that from
> bpftool, it would be great.
>
> Thoughts?
IMO it's all legacy at this point. If we can remove / simplify by
calling higher level abstraction from libbpf - there is no reason not
to do it.
