From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1471BC47088 for ; Thu, 1 Dec 2022 18:21:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230472AbiLASVW (ORCPT ); Thu, 1 Dec 2022 13:21:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230110AbiLASVT (ORCPT ); Thu, 1 Dec 2022 13:21:19 -0500 Received: from mail-ej1-x62a.google.com (mail-ej1-x62a.google.com [IPv6:2a00:1450:4864:20::62a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 775BAA430F; Thu, 1 Dec 2022 10:21:18 -0800 (PST) Received: by mail-ej1-x62a.google.com with SMTP id td2so6192005ejc.5; Thu, 01 Dec 2022 10:21:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=kN4208hsce3SHRoaG9mzfo6G9M6qlvqdZeD2xS9Y30Y=; b=Kn7lsPSRaeviDF4KcfkeCZMoKGapjvtJZ4qGaRJ/mcJnBdd5f4eJoQeJnTuMFRK623 9LdYB2n+ZDPwgx9bIp8bal3xXnlLWAkk5CJm1E0eMTkkB6z6n0zFP3FFz+4UdeCRItAx +umcntRjf+isG3Dct/aWhQV9NGCyEJkPWR799uRUU44OTku+H/rQUq0J/Kh8BBo7duAN 4bCRYnUq2oJ8da5DbQmGOHVskBfUr0RF+gyxGuqLyG23lOllKfLPDXadNlleJlObttsw M0k97aknVVwC37MT3qpSjj5zwI6+SoRQw2Uw+hZKdhPmR+T4npSIA4Bl1ut2TNludqyl OkbA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=kN4208hsce3SHRoaG9mzfo6G9M6qlvqdZeD2xS9Y30Y=; b=h5bFCUE9i/LNqRZvmettVy9Qj+v6AqZzpThkNDTRlZ4malytLaB2Ik7fcTgSShqhQq CD+SgsNSku4+EQvE0mt9xaG970N286U1+OH9xmlJiqCnUG8J5emXM6zBFuR8QxcMo5GI DueyH2CU7zCsGxM2e3L31CIuP++X7L9MQt1QCp5jecBwD7SZZrhQQ1A2LQhUH6Z9HCWH kpfrqtlXb8wCw8TITncT4/12AT1oSKn/QTKEe29mU1tv5DSIT/dvRhH5NkpP8n1w2Onm 20Q+ZrsMUnPGx2oYpXxf01gd8tTDfaudELpcW6dua/ImD3yvjl7WTlcZqgOan00OTWmj eHhg== X-Gm-Message-State: ANoB5pkSu5fxg7MJkE+FIjdGL0TxIbU3ktmdgEC69LLWxTRz5tcpI8jq 2wlPhu2/ne271siwylo8iS7ALQ+QpxPBxBfnA0E= X-Google-Smtp-Source: AA0mqf6bS4ZWZp4LkTyr+VR9fFZzERdRmQ590gokW1YJVyl5Cyn6gJPqOVqdOvX/Kd5m1hHqQBr2J8embxFnZzIja/Y= X-Received: by 2002:a17:906:180e:b0:7a2:6d38:1085 with SMTP id v14-20020a170906180e00b007a26d381085mr40905835eje.114.1669918876737; Thu, 01 Dec 2022 10:21:16 -0800 (PST) MIME-Version: 1.0 References: <20221124151603.807536-1-benjamin.tissoires@redhat.com> <20221124151603.807536-2-benjamin.tissoires@redhat.com> In-Reply-To: From: Andrii Nakryiko Date: Thu, 1 Dec 2022 10:21:03 -0800 Message-ID: Subject: Re: [RFC hid v1 01/10] bpftool: generate json output of skeletons To: Benjamin Tissoires Cc: Greg KH , Jiri Kosina , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Dmitry Torokhov , Tero Kristo , linux-kernel@vger.kernel.org, linux-input@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 1, 2022 at 6:23 AM Benjamin Tissoires wrote: > > On Thu, Dec 1, 2022 at 12:06 AM Andrii Nakryiko > wrote: > > > > On Thu, Nov 24, 2022 at 7:16 AM Benjamin Tissoires > > wrote: > > > > > > So we can then build light skeletons with loaders in any language. > > > > > > > It would be useful to include an example generated JSON. Other than > > that the overall idea makes sense. Kind of machine-friendly "BPF > > object schema" to allow automation. > > > > Great :) > I'll add the generated example in v2 then. > > However, I have problems figuring out how I can hit the > "codegen_datasecs()" path. I think that's the only code path I am not > duplicating from the do_skeleton() function, but I don't know what > kind of .bpf.c program will trigger that part. > You'll hit this whenever you have global variables in your .bpf.c code. It's very important part, so let's make sure it is covered. Try using both `const volatile` read-only variables (they will end up in .rodata datasec) and global non-read-only variables (they will go into .data, if initialized to non-zero defaults, or .bss if zero-initialized). > Also, should I add some tests for it in tools/testing/selftests/bpf? Yes, it probably makes sense to check expected JSON output is generated for a few example BPF object files. > > Cheers, > Benjamin > > > > Signed-off-by: Benjamin Tissoires > > > --- > > > tools/bpf/bpftool/gen.c | 95 +++++++++++++++++++++++++++++++++++++++++ > > > 1 file changed, 95 insertions(+) > > > > > > diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c > > > index cf8b4e525c88..818a5209b3ac 100644 > > > --- a/tools/bpf/bpftool/gen.c > > > +++ b/tools/bpf/bpftool/gen.c > > > @@ -904,6 +904,96 @@ codegen_progs_skeleton(struct bpf_object *obj, size_t prog_cnt, bool populate_li > > > } > > > } > > > > > > +static int gen_json(struct bpf_object *obj, const char *obj_name, size_t file_sz, uint8_t *obj_data) > > > +{ > > > + struct bpf_program *prog; > > > + struct bpf_map *map; > > > + char ident[256]; > > > + > > > + jsonw_start_object(json_wtr); /* root object */ > > > + > > > + jsonw_string_field(json_wtr, "name", obj_name); > > > + > > > + jsonw_bool_field(json_wtr, "use_loader", use_loader); > > > + > > > + /* print all maps */ > > > + jsonw_name(json_wtr, "maps"); > > > + jsonw_start_array(json_wtr); > > > + bpf_object__for_each_map(map, obj) { > > > + if (!get_map_ident(map, ident, sizeof(ident))) { > > > + p_err("ignoring unrecognized internal map '%s'...", > > > + bpf_map__name(map)); > > > + continue; > > > + } > > > + > > > + jsonw_start_object(json_wtr); /* map object */ > > > + jsonw_string_field(json_wtr, "ident", ident); > > > + jsonw_string_field(json_wtr, "name", bpf_map__name(map)); > > > + > > > + /* print mmap data value */ > > > + if (is_internal_mmapable_map(map, ident, sizeof(ident))) { > > > + const void *mmap_data = NULL; > > > + size_t mmap_size = 0; > > > + > > > + mmap_data = bpf_map__initial_value(map, &mmap_size); > > > + > > > + jsonw_uint_field(json_wtr, "size", mmap_size); > > > + jsonw_uint_field(json_wtr, "mmap_sz", bpf_map_mmap_sz(map)); > > > + jsonw_name(json_wtr, "data"); > > > + print_hex_data_json((uint8_t *)mmap_data, mmap_size); > > > + > > > + } > > > + jsonw_end_object(json_wtr); /* map object */ > > > + } > > > + jsonw_end_array(json_wtr); > > > + > > > + /* print all progs */ > > > + jsonw_name(json_wtr, "progs"); > > > + jsonw_start_array(json_wtr); > > > + bpf_object__for_each_program(prog, obj) { > > > + jsonw_start_object(json_wtr); /* prog object */ > > > + jsonw_string_field(json_wtr, "name", bpf_program__name(prog)); > > > + jsonw_string_field(json_wtr, "sec", bpf_program__section_name(prog)); > > > + jsonw_end_object(json_wtr); /* prog object */ > > > + } > > > + jsonw_end_array(json_wtr); > > > + > > > + /* print object data */ > > > + if (use_loader) { > > > + DECLARE_LIBBPF_OPTS(gen_loader_opts, opts); > > > + int err = 0; > > > + > > > + err = bpf_object__gen_loader(obj, &opts); > > > + if (err) > > > + return err; > > > + > > > + err = bpf_object__load(obj); > > > + if (err) { > > > + p_err("failed to load object file"); > > > + return err; > > > + } > > > + /* If there was no error during load then gen_loader_opts > > > + * are populated with the loader program. > > > + */ > > > + > > > + jsonw_uint_field(json_wtr, "data_sz", opts.data_sz); > > > + jsonw_name(json_wtr, "data"); > > > + print_hex_data_json((uint8_t *)opts.data, opts.data_sz); > > > + > > > + jsonw_uint_field(json_wtr, "insns_sz", opts.insns_sz); > > > + jsonw_name(json_wtr, "insns"); > > > + print_hex_data_json((uint8_t *)opts.insns, opts.insns_sz); > > > + > > > + } else { > > > + jsonw_name(json_wtr, "data"); > > > + print_hex_data_json(obj_data, file_sz); > > > + } > > > + > > > + jsonw_end_object(json_wtr); /* root object */ > > > + > > > + return 0; > > > +} > > > + > > > static int do_skeleton(int argc, char **argv) > > > { > > > char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SKEL_H__")]; > > > @@ -986,6 +1076,11 @@ static int do_skeleton(int argc, char **argv) > > > goto out; > > > } > > > > > > + if (json_output) { > > > + err = gen_json(obj, obj_name, file_sz, (uint8_t *)obj_data); > > > + goto out; > > > + } > > > + > > > bpf_object__for_each_map(map, obj) { > > > if (!get_map_ident(map, ident, sizeof(ident))) { > > > p_err("ignoring unrecognized internal map '%s'...", > > > -- > > > 2.38.1 > > > > > >