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 X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31BA1C433ED for ; Mon, 26 Apr 2021 22:35:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0D0BA6101D for ; Mon, 26 Apr 2021 22:35:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235991AbhDZWgK (ORCPT ); Mon, 26 Apr 2021 18:36:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42208 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232161AbhDZWgJ (ORCPT ); Mon, 26 Apr 2021 18:36:09 -0400 Received: from mail-yb1-xb2f.google.com (mail-yb1-xb2f.google.com [IPv6:2607:f8b0:4864:20::b2f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93C1EC061574; Mon, 26 Apr 2021 15:35:27 -0700 (PDT) Received: by mail-yb1-xb2f.google.com with SMTP id p126so13277391yba.1; Mon, 26 Apr 2021 15:35:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=NWagQn/COuoShM8WrVf9LFg9xKNV28jcvx8Exyu8PzY=; b=klRwomMCJt74+Pv/6iWw2/9qf48Bl8BXE4majBF8aBC6OjC2lTsD4QEEHx/VVCYIzX /9k76QhqQDDLFHgs5BK7xujejrQAegD221soV9yAGowd9wEHQxeXK9sDPFt03VrRqdQl S7PBU0cDS59CnnWpOA86ClebOrLuQy6NZ/T0CEiN42GCsu2bGFZPGzcJHeC/HsKcnNwL G61NabOZIW4jSzCJ/29kaTfIilodpev0s3ZX3umSfjU7m9r8r5Xceu71jayjmuhPMd3S Wivrule9lhspYUh8iJ/h3oPBugiccGNb/i+PfAnT9AFyUQFT/xO1FPpLe2qyD2YlOE/t tWQQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=NWagQn/COuoShM8WrVf9LFg9xKNV28jcvx8Exyu8PzY=; b=O3hhboAcg6VjWolrDdIqem3Zde6epbTlTxXdnfzUn9N5nFlyJ2Qyn9bT1b9j9YcmuK ZPnmxpItqFpgpk9xoxuqYEcLN1ScbSXzcLz2ietDWwWRxu8i1ULgK/m4MQh6s4vivWM8 SA1r3vjnvgl8E+8Fr69PDAkvuaw1iwfyh3TOVvPdKBSnfA+Z5+y0im9LeV+Fmmav/OXO 9+syOqhr5UKYfCzI7J1yQXu0Z1l8LnS5lrLFJlCn6iHQSO71qx1LcOEtfvdPpQvOZEwB h+hQ2iErcSdxpVAtsBD76DfyNji2r+2bzU6VvzXScBZwSmq4CgbyNv/ZA/U8nlGqMrdX rBmQ== X-Gm-Message-State: AOAM531rBjr1MtmQNsZ97B79sUnR8oMoRatqU5WvILWfaKDn1xiJLhlf Syappgaf/dI8vswj44f0NpTu3wNmOzbnrTpEAKZtUthx X-Google-Smtp-Source: ABdhPJyuKNgESmfzztTsrf7XiitRAHRoAnts2qv5j+uUHituKxkGmSC+gItgMpGTm1z9x4LMnl0G+O9kw+LJV60GORU= X-Received: by 2002:a25:2441:: with SMTP id k62mr27373194ybk.347.1619476526857; Mon, 26 Apr 2021 15:35:26 -0700 (PDT) MIME-Version: 1.0 References: <20210423002646.35043-1-alexei.starovoitov@gmail.com> <20210423002646.35043-16-alexei.starovoitov@gmail.com> In-Reply-To: <20210423002646.35043-16-alexei.starovoitov@gmail.com> From: Andrii Nakryiko Date: Mon, 26 Apr 2021 15:35:16 -0700 Message-ID: Subject: Re: [PATCH v2 bpf-next 15/16] bpftool: Use syscall/loader program in "prog load" and "gen skeleton" command. To: Alexei Starovoitov Cc: "David S. Miller" , Daniel Borkmann , Andrii Nakryiko , Networking , bpf , Kernel Team Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Thu, Apr 22, 2021 at 5:27 PM Alexei Starovoitov wrote: > > From: Alexei Starovoitov > > Add -L flag to bpftool to use libbpf gen_trace facility and syscall/loader program > for skeleton generation and program loading. > > "bpftool gen skeleton -L" command will generate a "light skeleton" or "loader skeleton" > that is similar to existing skeleton, but has one major difference: > $ bpftool gen skeleton lsm.o > lsm.skel.h > $ bpftool gen skeleton -L lsm.o > lsm.lskel.h > $ diff lsm.skel.h lsm.lskel.h > @@ -5,34 +4,34 @@ > #define __LSM_SKEL_H__ > > #include > -#include > +#include > > The light skeleton does not use majority of libbpf infrastructure. > It doesn't need libelf. It doesn't parse .o file. > It only needs few sys_bpf wrappers. All of them are in bpf/bpf.h file. > In future libbpf/bpf.c can be inlined into bpf.h, so not even libbpf.a would be > needed to work with light skeleton. > > "bpftool prog load -L file.o" command is introduced for debugging of syscall/loader > program generation. Just like the same command without -L it will try to load > the programs from file.o into the kernel. It won't even try to pin them. > > "bpftool prog load -L -d file.o" command will provide additional debug messages > on how syscall/loader program was generated. > Also the execution of syscall/loader program will use bpf_trace_printk() for > each step of loading BTF, creating maps, and loading programs. > The user can do "cat /.../trace_pipe" for further debug. > > An example of fexit_sleep.lskel.h generated from progs/fexit_sleep.c: > struct fexit_sleep { > struct bpf_loader_ctx ctx; > struct { > struct bpf_map_desc bss; > } maps; > struct { > struct bpf_prog_desc nanosleep_fentry; > struct bpf_prog_desc nanosleep_fexit; > } progs; > struct { > int nanosleep_fentry_fd; > int nanosleep_fexit_fd; > } links; > struct fexit_sleep__bss { > int pid; > int fentry_cnt; > int fexit_cnt; > } *bss; > }; > > Signed-off-by: Alexei Starovoitov > --- > tools/bpf/bpftool/Makefile | 2 +- > tools/bpf/bpftool/gen.c | 313 +++++++++++++++++++++++++++--- > tools/bpf/bpftool/main.c | 7 +- > tools/bpf/bpftool/main.h | 1 + > tools/bpf/bpftool/prog.c | 80 ++++++++ > tools/bpf/bpftool/xlated_dumper.c | 3 + > 6 files changed, 382 insertions(+), 24 deletions(-) > [...] > @@ -268,6 +269,254 @@ static void codegen(const char *template, ...) > free(s); > } > > +static void print_hex(const char *obj_data, int file_sz) > +{ > + int i, len; > + > + /* embed contents of BPF object file */ nit: this comment should have stayed at the original place > + for (i = 0, len = 0; i < file_sz; i++) { > + int w = obj_data[i] ? 4 : 2; > + [...] > + bpf_object__for_each_map(map, obj) { > + const char * ident; > + > + ident = get_map_ident(map); > + if (!ident) > + continue; > + > + if (!bpf_map__is_internal(map) || > + !(bpf_map__def(map)->map_flags & BPF_F_MMAPABLE)) > + continue; > + > + printf("\tskel->%1$s =\n" > + "\t\tmmap(NULL, %2$zd, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED,\n" > + "\t\t\tskel->maps.%1$s.map_fd, 0);\n", > + ident, bpf_map_mmap_sz(map)); use codegen()? > + } > + codegen("\ > + \n\ > + return 0; \n\ > + } \n\ > + \n\ > + static inline struct %1$s * \n\ [...] > static int do_skeleton(int argc, char **argv) > { > char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SKEL_H__")]; > @@ -277,7 +526,7 @@ static int do_skeleton(int argc, char **argv) > struct bpf_object *obj = NULL; > const char *file, *ident; > struct bpf_program *prog; > - int fd, len, err = -1; > + int fd, err = -1; > struct bpf_map *map; > struct btf *btf; > struct stat st; > @@ -359,7 +608,25 @@ static int do_skeleton(int argc, char **argv) > } > > get_header_guard(header_guard, obj_name); > - codegen("\ > + if (use_loader) please use {} for such a long if/else, even if it's, technically, a single-statement if > + codegen("\ > + \n\ > + /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\ > + /* THIS FILE IS AUTOGENERATED! */ \n\ > + #ifndef %2$s \n\ > + #define %2$s \n\ > + \n\ > + #include \n\ > + #include \n\ > + #include \n\ > + \n\ > + struct %1$s { \n\ > + struct bpf_loader_ctx ctx; \n\ > + ", > + obj_name, header_guard > + ); > + else > + codegen("\ > \n\ > /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\ > \n\ [...]