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=-14.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no 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 14E12C43461 for ; Fri, 11 Sep 2020 16:00:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BA52221D47 for ; Fri, 11 Sep 2020 16:00:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="q6mTZynv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725959AbgIKP75 (ORCPT ); Fri, 11 Sep 2020 11:59:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38388 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726575AbgIKP4b (ORCPT ); Fri, 11 Sep 2020 11:56:31 -0400 Received: from mail-qt1-x841.google.com (mail-qt1-x841.google.com [IPv6:2607:f8b0:4864:20::841]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 73CA7C061756 for ; Fri, 11 Sep 2020 08:56:31 -0700 (PDT) Received: by mail-qt1-x841.google.com with SMTP id z2so8182891qtv.12 for ; Fri, 11 Sep 2020 08:56:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=HB1wLkJBUPBITqr249AFzq+PR4Y7nrQ2PRnzX2SICNU=; b=q6mTZynvnuOIdXFxtOD49r+38vJ9B5saRc3IwrULNNlQw4i2QImBldf6kJg536NWqQ GuKZ/xQg/z2eqdHj+zDrvIhQNnmNLfLw8ECIGw+EwdIEgxnu0xezOYq9N/7fndQWfmag 6k+kkjfPeDFhTJC/hptFfjQQV38r2owSheIlqMRlvKQ+bcAIVgYNuNe9Bvzi1nbxTduG /u4KOemjjBSZk5dPMYz7NCp2aWO/jA58SA8yHuUSzGtFHCHJ0/7X5MYTKzb3Ks50byML 85feoiOX3GWXU03Gi6PcPD2H0JbSQvT5ljbgA+baUamBozteFMGwONWP3fwYRozpHxCy Ojpg== 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=HB1wLkJBUPBITqr249AFzq+PR4Y7nrQ2PRnzX2SICNU=; b=L6uvyQYuomvoVbHPA1aV3okW8d/uYZr4Xb8UpMYV0wt26XMdnIFL4bHM8jI2dRXKTM l6X5Xwe1xlymoQlVnLWVh5L9444duIcbzLjc2R4pK7Y5GcEEjfpL0tfsprtveOLtKaDH Zajrlv0KJZKJ3c4tjDLJ5lYmGPuMy9OYITEmeQAa7txjVDDqJJYi3lHbPg++Bnp+OEf8 XOeo0TkcFkqlBkhCsCtGDuDXjFKmZPfZp6g96SnnS+3oEurDlJ0sQiaetG4Rv56NAARn +FFi+p5tXnYPaxEihVooM+/HwoCWIboK5sqjj0nTNsxDxQVGiTLXGkdGJpnSWZlhCCbw 8j9w== X-Gm-Message-State: AOAM530oux0X8/lMrAg31q4R4F3RStsTHMTUU9Ma7wU0XLFeX6T6deAB BthJ+azXq3zsPm9Kk+yk0RrxE48yayF61CAjRrp31Q== X-Google-Smtp-Source: ABdhPJwX6e9cju+FL0v94+Z0/0T0ORtkFdzm5HvbrtkrybQyiKcZ93D1C9S02/CEAgsWDiMYufPy6anpHcb8ShTao1Q= X-Received: by 2002:ac8:4784:: with SMTP id k4mr2595978qtq.266.1599839790431; Fri, 11 Sep 2020 08:56:30 -0700 (PDT) MIME-Version: 1.0 References: <20200909182406.3147878-1-sdf@google.com> <20200909182406.3147878-5-sdf@google.com> In-Reply-To: From: Stanislav Fomichev Date: Fri, 11 Sep 2020 08:56:19 -0700 Message-ID: Subject: Re: [PATCH bpf-next v4 4/5] bpftool: support dumping metadata To: Andrii Nakryiko Cc: Networking , bpf , "David S. Miller" , Alexei Starovoitov , Daniel Borkmann , YiFei Zhu Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Sep 10, 2020 at 12:54 PM Andrii Nakryiko wrote: > > On Wed, Sep 9, 2020 at 11:25 AM Stanislav Fomichev wrote: > > diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c > > index f7923414a052..ca264dc22434 100644 > > --- a/tools/bpf/bpftool/prog.c > > +++ b/tools/bpf/bpftool/prog.c > > @@ -29,6 +29,9 @@ > > #include "main.h" > > #include "xlated_dumper.h" > > > > +#define BPF_METADATA_PREFIX "bpf_metadata_" > > +#define BPF_METADATA_PREFIX_LEN strlen(BPF_METADATA_PREFIX) > > this is a runtime check, why not (sizeof(BPF_METADATA_PREFIX) - 1) instead? Make sense, will fix. > > +static int bpf_prog_find_metadata(int prog_fd, int *map_id) > > ... > > +free_map_ids: > > + saved_errno = errno; > > + free(map_ids); > > + errno = saved_errno; > > not clear why all this fussing with saving/restoring errno and then > just returning 0 or -1? Just return -ENOMEM or -ENOENT as a result of > this function? Yeah, I just moved this function from it's original (libbpf) location as is. I guess it makes sense to simplify the error handling now that it's not in exported from libbpf. > > + if (bpf_map_lookup_elem(map_fd, &key, value)) > > + goto out_free; > > + > > + err = btf__get_from_id(map_info.btf_id, &btf); > > + if (err || !btf) > > + goto out_free; > > if you make bpf_prog_find_metadata() to do this value lookup and pass > &info, it would probably make bpf_prog_find_metadata a bit more > usable? You'll just need to ensure that callers free allocated memory. > Then show_prog_metadata() would take care of processing BTF info. Sounds reasonable. I can maybe keep existing bpf_prog_find_metadata (rename to bpf_prog_find_metadata_map_id?) and add another wrapper that does that map lookup.