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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 92498C47E49 for ; Fri, 25 Oct 2019 16:31:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6294420663 for ; Fri, 25 Oct 2019 16:31:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=netronome-com.20150623.gappssmtp.com header.i=@netronome-com.20150623.gappssmtp.com header.b="BwtEXlJc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2408066AbfJYQbX (ORCPT ); Fri, 25 Oct 2019 12:31:23 -0400 Received: from mail-pl1-f180.google.com ([209.85.214.180]:45058 "EHLO mail-pl1-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391211AbfJYQbX (ORCPT ); Fri, 25 Oct 2019 12:31:23 -0400 Received: by mail-pl1-f180.google.com with SMTP id y24so1486405plr.12 for ; Fri, 25 Oct 2019 09:31:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netronome-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :organization:mime-version:content-transfer-encoding; bh=1EUj3irj6XVPBQ7Z9U8k8kcmlKkmc6kitqhex26/WnQ=; b=BwtEXlJcQ20cGQDYIU0gfNYys1FpKTgFQKDLWNAUjvxMX2F14kbUC3qhq96Z0ctb7h lRnPUrg3flmm1/MWivhAZAQAEUEsf6Mh0ZPOD36R56J4PIHmtFfM6XR37CveYwE6yUlI NqAbJ61nbX/ByJzeus/lVFpOxvGYJDOrtSqAJc75b7zsAQ3AUXS5JBRRPRNbICHcTV48 20rPm5BTtmnOdADNFins1B6g38HPS2lYb7IvuDLnoKwv6wNFDfD53RFTi2VF4V8YVgDq Vodepyjg+xpt8wRjx7AqRXIcG5TmQecDJBFKpocxnxX8hNjxs/dmM72U0W+5LVMGXGcd PR9w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:organization:mime-version:content-transfer-encoding; bh=1EUj3irj6XVPBQ7Z9U8k8kcmlKkmc6kitqhex26/WnQ=; b=bL05m1WBbquofuApSOdjwwk3Aq0sG1uxaQB7SjSNws9+BLoMGwrIZH0sLJFj/mtRFc q3gAhP+6e8ibqlS/XGfsiiWoiYAGPBEA+u0nbKGZ5joYwVtNF6wJXWRPb026wm/Xf0Zo 9oP5MDIEnlRE7+Kqa9A0b6rfrAfs6f5+lx+gh9k/bFVFEsRA3NxeXQI5ikqQuwCLgn4j 8wT3g7ADZS/7/1QAKYDvCBO+KaFl/maZHStj8JNaK/hfgGpbH33r7hANrJUTo0ja2RNI pO1HG5fGScI1RgxXIWwtmy/zGLdU6oxLvrWK2ciQGjfjlFZMDFDjKsRg7hZURnzSzSZT bmww== X-Gm-Message-State: APjAAAWFpA5Uf0fxz/5gdqog75FwQG901oJ8ijMAK2vtR40cmU4gZ0lB 2CIJM0NpB+v7ur5v9QE/y6Jhiw== X-Google-Smtp-Source: APXvYqxIgWYAro3JplidCsKmEFeX4IA3PodO6Cd0sdWb14wx/ymxyllaQfpPEWRPtsASesqW2n/1Kw== X-Received: by 2002:a17:902:7885:: with SMTP id q5mr4646650pll.317.1572021081092; Fri, 25 Oct 2019 09:31:21 -0700 (PDT) Received: from cakuba.hsd1.ca.comcast.net (c-73-202-202-92.hsd1.ca.comcast.net. [73.202.202.92]) by smtp.gmail.com with ESMTPSA id y20sm2822910pge.48.2019.10.25.09.31.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 25 Oct 2019 09:31:20 -0700 (PDT) Date: Fri, 25 Oct 2019 09:31:16 -0700 From: Jakub Kicinski To: Andrii Nakryiko Cc: Jiri Olsa , Alexei Starovoitov , Daniel Borkmann , "netdev@vger.kernel.org" , "bpf@vger.kernel.org" , Yonghong Song , Martin Lau , "andrii.nakryiko@gmail.com" Subject: Re: [PATCHv2] bpftool: Try to read btf as raw data if elf read fails Message-ID: <20191025093116.67756660@cakuba.hsd1.ca.comcast.net> In-Reply-To: References: <20191024132341.8943-1-jolsa@kernel.org> <20191024105414.65f7e323@cakuba.hsd1.ca.comcast.net> Organization: Netronome Systems, Ltd. MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, 25 Oct 2019 05:01:17 +0000, Andrii Nakryiko wrote: > >> +static bool is_btf_raw(const char *file) > >> +{ > >> + __u16 magic = 0; > >> + int fd; > >> + > >> + fd = open(file, O_RDONLY); > >> + if (fd < 0) > >> + return false; > >> + > >> + read(fd, &magic, sizeof(magic)); > >> + close(fd); > >> + return magic == BTF_MAGIC; > > > > Isn't it suspicious to read() 2 bytes into an u16 and compare to a > > constant like endianness doesn't matter? Quick grep doesn't reveal > > BTF_MAGIC being endian-aware.. > > Right now we support only loading BTF in native endianness, so I think > this should do. If we ever add ability to load non-native endianness, > then we'll have to adjust this. This doesn't do native endianness, this does LE-only. It will not work on BE machines.