On Wed, Sep 21, 2022 at 12:40 AM Wang Yufen <wangyufen@xxxxxxxxxx> wrote: > > Add auto_attach optional to support one-step load-attach-pin_link. > > For example, > $ bpftool prog loadall test.o /sys/fs/bpf/test auto_attach > > $ bpftool link > 26: tracing name test1 tag f0da7d0058c00236 gpl > loaded_at 2022-09-09T21:39:49+0800 uid 0 > xlated 88B jited 55B memlock 4096B map_ids 3 > btf_id 55 > 28: kprobe name test3 tag 002ef1bef0723833 gpl > loaded_at 2022-09-09T21:39:49+0800 uid 0 > xlated 88B jited 56B memlock 4096B map_ids 3 > btf_id 55 > 57: tracepoint name oncpu tag 7aa55dfbdcb78941 gpl > loaded_at 2022-09-09T21:41:32+0800 uid 0 > xlated 456B jited 265B memlock 4096B map_ids 17,13,14,15 > btf_id 82 > > $ bpftool link > 1: tracing prog 26 > prog_type tracing attach_type trace_fentry > 3: perf_event prog 28 > 10: perf_event prog 57 > > The auto_attach optional can support tracepoints, k(ret)probes, > u(ret)probes. > > Signed-off-by: Wei Yongjun <weiyongjun1@xxxxxxxxxx> > Signed-off-by: Wang Yufen <wangyufen@xxxxxxxxxx> > Reviewed-by: Quentin Monnet <quentin@xxxxxxxxxxxxx> > --- > v4 -> v5: some formatting nits of doc > v3 -> v4: rename functions, update doc, bash and do_help() > v2 -> v3: switch to extend prog load command instead of extend perf > v2: https://patchwork.kernel.org/project/netdevbpf/patch/20220824033837.458197-1-weiyongjun1@xxxxxxxxxx/ > v1: https://patchwork.kernel.org/project/netdevbpf/patch/20220816151725.153343-1-weiyongjun1@xxxxxxxxxx/ > tools/bpf/bpftool/prog.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 75 insertions(+), 2 deletions(-) > > diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c > index c81362a..aea0b57 100644 > --- a/tools/bpf/bpftool/prog.c > +++ b/tools/bpf/bpftool/prog.c > @@ -1453,6 +1453,68 @@ static int do_run(int argc, char **argv) > return ret; > } > > +static int > +auto_attach_program(struct bpf_program *prog, const char *path) > +{ > + struct bpf_link *link; > + int err; > + > + link = bpf_program__attach(prog); > + err = libbpf_get_error(link); nit: bpftool uses libbpf 1.0, so no need to use libbpf_get_error() anymore, you can just check link for NULL and then look at errno but I wanted to check on desired behavior here. BPF skeleton will skip programs that can't be auto-attached because they are of the type that can't be declaratively specified to be auto-attachable. For such programs bpf_program__attach() will return -EOPNOTSUPP and libbpf's skeleton_attach API will silently skip them. Should bpftool be stricter about such programs here or should it follow BPF skeleton approach? > + if (err) > + return err; > + > + err = bpf_link__pin(link, path); > + if (err) { > + bpf_link__destroy(link); > + return err; > + } > + return 0; > +} > + > +static int pathname_concat(const char *path, const char *name, char *buf) you added buffer size in libbpf version of this function, maybe match the same signature (I also moved buf and buf_sz to be first two args). > +{ > + int len; > + > + len = snprintf(buf, PATH_MAX, "%s/%s", path, name); > + if (len < 0) > + return -EINVAL; > + if (len >= PATH_MAX) > + return -ENAMETOOLONG; > + > + return 0; > +} > + > +static int > +auto_attach_programs(struct bpf_object *obj, const char *path) > +{ > + struct bpf_program *prog; > + char buf[PATH_MAX]; > + int err; > + > + bpf_object__for_each_program(prog, obj) { > + err = pathname_concat(path, bpf_program__name(prog), buf); > + if (err) > + goto err_unpin_programs; > + > + err = auto_attach_program(prog, buf); > + if (err) > + goto err_unpin_programs; > + } > + would it be safer to first make sure that all programs are auto-attached and then pin links? also note that not all bpf_links returned by libbpf are actual links in kernel (e.g., kprobe/tp bpf_link on older kernels). > + return 0; > + > +err_unpin_programs: > + while ((prog = bpf_object__prev_program(obj, prog))) { > + if (pathname_concat(path, bpf_program__name(prog), buf)) > + continue; > + > + bpf_program__unpin(prog, buf); > + } > + > + return err; > +} > + > static int load_with_options(int argc, char **argv, bool first_prog_only) > { > enum bpf_prog_type common_prog_type = BPF_PROG_TYPE_UNSPEC; > @@ -1464,6 +1526,7 @@ static int load_with_options(int argc, char **argv, bool first_prog_only) > struct bpf_program *prog = NULL, *pos; > unsigned int old_map_fds = 0; > const char *pinmaps = NULL; > + bool auto_attach = false; > struct bpf_object *obj; > struct bpf_map *map; > const char *pinfile; > @@ -1583,6 +1646,9 @@ static int load_with_options(int argc, char **argv, bool first_prog_only) > goto err_free_reuse_maps; > > pinmaps = GET_ARG(); > + } else if (is_prefix(*argv, "auto_attach")) { > + auto_attach = true; > + NEXT_ARG(); > } else { > p_err("expected no more arguments, 'type', 'map' or 'dev', got: '%s'?", > *argv); > @@ -1692,14 +1758,20 @@ static int load_with_options(int argc, char **argv, bool first_prog_only) > goto err_close_obj; > } > > - err = bpf_obj_pin(bpf_program__fd(prog), pinfile); > + if (auto_attach) > + err = auto_attach_program(prog, pinfile); > + else > + err = bpf_obj_pin(bpf_program__fd(prog), pinfile); > if (err) { > p_err("failed to pin program %s", > bpf_program__section_name(prog)); > goto err_close_obj; > } > } else { > - err = bpf_object__pin_programs(obj, pinfile); > + if (auto_attach) > + err = auto_attach_programs(obj, pinfile); > + else > + err = bpf_object__pin_programs(obj, pinfile); > if (err) { > p_err("failed to pin all programs"); > goto err_close_obj; > @@ -2338,6 +2410,7 @@ static int do_help(int argc, char **argv) > " [type TYPE] [dev NAME] \\\n" > " [map { idx IDX | name NAME } MAP]\\\n" > " [pinmaps MAP_DIR]\n" > + " [auto_attach]\n" looking at "pinmaps" seems like "autoattach" would be more consistent naming? Or just "attach"? > " %1$s %2$s attach PROG ATTACH_TYPE [MAP]\n" > " %1$s %2$s detach PROG ATTACH_TYPE [MAP]\n" > " %1$s %2$s run PROG \\\n" > -- > 1.8.3.1 >
