Tue Sep 27 2022 12:21:14 GMT+0100 ~ Wang Yufen <wangyufen@xxxxxxxxxx> > Add auto_attach optional to support one-step load-attach-pin_link. Nit: Now "autoattach" instead of "auto_attach". Same in commit title. > > For example, > $ bpftool prog loadall test.o /sys/fs/bpf/test autoattach > > $ 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 autoattach optional can support tracepoints, k(ret)probes, > u(ret)probes. > > Signed-off-by: Wei Yongjun <weiyongjun1@xxxxxxxxxx> > Signed-off-by: Wang Yufen <wangyufen@xxxxxxxxxx> > --- > v6 -> v7: add info msg print and update doc for the skip program > v5 -> v6: skip the programs not supporting auto-attach, > and change optional name from "auto_attach" to "autoattach" > 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 | 81 ++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 79 insertions(+), 2 deletions(-) > > diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c > index c81362a..84eced8 100644 > --- a/tools/bpf/bpftool/prog.c > +++ b/tools/bpf/bpftool/prog.c > @@ -1453,6 +1453,72 @@ 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); > + if (!link) > + return -1; > + > + 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) > +{ > + 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) > + continue; > + if (errno == EOPNOTSUPP) > + p_info("Program %s does not support autoattach", > + bpf_program__name(prog)); > + else > + goto err_unpin_programs With this code, if auto-attach fails, then we skip this program and move on to the next. That's an improvement, but in that case the program won't remain loaded in the kernel after bpftool exits. My suggestion in my previous message (sorry if it was not clear) was to fall back to regular pinning in that case (bpf_obj_pin()), along with the p_info() message, so we can have the program pinned but not attached and let the user know. If regular pinning fails as well, then we should unpin all and error out, for consistency with bpf_object__pin_programs(). And in that case, the (errno == EOPNOTSUPP) with fallback to regular pinning could maybe be moved into auto_attach_program(), so that auto-attaching single programs can use the fallback too? Thanks, Quentin
