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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 B26A3C433FF for ; Tue, 30 Jul 2019 19:23:25 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 82E0120679 for ; Tue, 30 Jul 2019 19:23:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 82E0120679 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:35978 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hsXiW-0008JE-SN for qemu-devel@archiver.kernel.org; Tue, 30 Jul 2019 15:23:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55834) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hsXhb-0007IE-QH for qemu-devel@nongnu.org; Tue, 30 Jul 2019 15:22:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hsXha-0000r8-Ig for qemu-devel@nongnu.org; Tue, 30 Jul 2019 15:22:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38644) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hsXhY-0000ow-00; Tue, 30 Jul 2019 15:22:24 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 065AD8553F; Tue, 30 Jul 2019 19:22:23 +0000 (UTC) Received: from [10.3.116.93] (ovpn-116-93.phx2.redhat.com [10.3.116.93]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 818255D6A7; Tue, 30 Jul 2019 19:22:22 +0000 (UTC) To: Max Reitz , qemu-block@nongnu.org References: <20190730172508.19911-1-mreitz@redhat.com> <20190730172508.19911-13-mreitz@redhat.com> From: Eric Blake Openpgp: preference=signencrypt Autocrypt: addr=eblake@redhat.com; keydata= xsBNBEvHyWwBCACw7DwsQIh0kAbUXyqhfiKAKOTVu6OiMGffw2w90Ggrp4bdVKmCaEXlrVLU xphBM8mb+wsFkU+pq9YR621WXo9REYVIl0FxKeQo9dyQBZ/XvmUMka4NOmHtFg74nvkpJFCD TUNzmqfcjdKhfFV0d7P/ixKQeZr2WP1xMcjmAQY5YvQ2lUoHP43m8TtpB1LkjyYBCodd+LkV GmCx2Bop1LSblbvbrOm2bKpZdBPjncRNob73eTpIXEutvEaHH72LzpzksfcKM+M18cyRH+nP sAd98xIbVjm3Jm4k4d5oQyE2HwOur+trk2EcxTgdp17QapuWPwMfhaNq3runaX7x34zhABEB AAHNHkVyaWMgQmxha2UgPGVibGFrZUByZWRoYXQuY29tPsLAegQTAQgAJAIbAwULCQgHAwUV CgkICwUWAgMBAAIeAQIXgAUCS8fL9QIZAQAKCRCnoWtKJSdDahBHCACbl/5FGkUqJ89GAjeX RjpAeJtdKhujir0iS4CMSIng7fCiGZ0fNJCpL5RpViSo03Q7l37ss+No+dJI8KtAp6ID+PMz wTJe5Egtv/KGUKSDvOLYJ9WIIbftEObekP+GBpWP2+KbpADsc7EsNd70sYxExD3liwVJYqLc Rw7so1PEIFp+Ni9A1DrBR5NaJBnno2PHzHPTS9nmZVYm/4I32qkLXOcdX0XElO8VPDoVobG6 gELf4v/vIImdmxLh/w5WctUpBhWWIfQDvSOW2VZDOihm7pzhQodr3QP/GDLfpK6wI7exeu3P pfPtqwa06s1pae3ad13mZGzkBdNKs1HEm8x6zsBNBEvHyWwBCADGkMFzFjmmyqAEn5D+Mt4P zPdO8NatsDw8Qit3Rmzu+kUygxyYbz52ZO40WUu7EgQ5kDTOeRPnTOd7awWDQcl1gGBXgrkR pAlQ0l0ReO57Q0eglFydLMi5bkwYhfY+TwDPMh3aOP5qBXkm4qIYSsxb8A+i00P72AqFb9Q7 3weG/flxSPApLYQE5qWGSXjOkXJv42NGS6o6gd4RmD6Ap5e8ACo1lSMPfTpGzXlt4aRkBfvb NCfNsQikLZzFYDLbQgKBA33BDeV6vNJ9Cj0SgEGOkYyed4I6AbU0kIy1hHAm1r6+sAnEdIKj cHi3xWH/UPrZW5flM8Kqo14OTDkI9EtlABEBAAHCwF8EGAEIAAkFAkvHyWwCGwwACgkQp6Fr SiUnQ2q03wgAmRFGDeXzc58NX0NrDijUu0zx3Lns/qZ9VrkSWbNZBFjpWKaeL1fdVeE4TDGm I5mRRIsStjQzc2R9b+2VBUhlAqY1nAiBDv0Qnt+9cLiuEICeUwlyl42YdwpmY0ELcy5+u6wz mK/jxrYOpzXKDwLq5k4X+hmGuSNWWAN3gHiJqmJZPkhFPUIozZUCeEc76pS/IUN72NfprZmF Dp6/QDjDFtfS39bHSWXKVZUbqaMPqlj/z6Ugk027/3GUjHHr8WkeL1ezWepYDY7WSoXwfoAL 2UXYsMAr/uUncSKlfjvArhsej0S4zbqim2ZY6S8aRWw94J3bSvJR+Nwbs34GPTD4Pg== Organization: Red Hat, Inc. Message-ID: <90984be8-3181-03aa-57e4-7e3c46cec6f8@redhat.com> Date: Tue, 30 Jul 2019 14:22:21 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20190730172508.19911-13-mreitz@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="ZABI0nTGYlvu8QsADX28yH8olsHEWfwf7" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Tue, 30 Jul 2019 19:22:23 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH for-4.2 12/13] iotests: Add peek_file* functions X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --ZABI0nTGYlvu8QsADX28yH8olsHEWfwf7 Content-Type: multipart/mixed; boundary="9g9J96uGF2eX7XyD52ujBCfRhBqJaA7I6"; protected-headers="v1" From: Eric Blake To: Max Reitz , qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Kevin Wolf Message-ID: <90984be8-3181-03aa-57e4-7e3c46cec6f8@redhat.com> Subject: Re: [PATCH for-4.2 12/13] iotests: Add peek_file* functions References: <20190730172508.19911-1-mreitz@redhat.com> <20190730172508.19911-13-mreitz@redhat.com> In-Reply-To: <20190730172508.19911-13-mreitz@redhat.com> --9g9J96uGF2eX7XyD52ujBCfRhBqJaA7I6 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 7/30/19 12:25 PM, Max Reitz wrote: > Signed-off-by: Max Reitz > --- > tests/qemu-iotests/common.rc | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) >=20 > diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.r= c > index 5502c3da2f..78decfd5d5 100644 > --- a/tests/qemu-iotests/common.rc > +++ b/tests/qemu-iotests/common.rc > @@ -53,6 +53,26 @@ poke_file() > printf "$3" | dd "of=3D$1" bs=3D1 "seek=3D$2" conv=3Dnotrunc &>/de= v/null > } > =20 > +# peek_file_le 'test.img' 512 2 =3D> 65534 > +peek_file_le() > +{ > + # Wrap in echo $() to strip spaces > + echo $(od -j"$2" -N"$3" --endian=3Dlittle -An -vtu"$3" "$1") Requires coreutils' od, but we can patch that later if it proves to be a problem on other hosts. I used to do something similar in nbdkit (prior to qemu-nbd --list making my life a lot easier; see nbdkit commit b228cb40); but there, I read a 16-bit value in 2 8-bit chunks and pieced it together myself rather than relying on --endian: - # Protocol is big endian, we want native endian. - # xargs trick to trim whitespace from - # https://stackoverflow.com/a/12973694 - eflags_hi=3D$(od -An -N1 -tx1 eflags.out | xargs) - eflags_lo=3D$(od -An -N1 -j1 -tx1 eflags.out | xargs) - eflags=3D$(( 0x$eflags_hi << 8 | 0x$eflags_lo )) But as long as we are using --endian, your version nicely handles 1, 2, 4, and 8-byte reads. > + > +# peek_file_raw 'test.img' 512 2 =3D> '\xff\xfe' > +peek_file_raw() > +{ > + dd if=3D"$1" bs=3D1 skip=3D"$2" count=3D"$3" status=3Dnone > +} Of course, calling $(peek_file_raw ...) is a bad idea, because it might eat a trailing byte that happened to be a newline; it also doesn't handle NUL bytes very well. Is it worth documenting caveats for using this one? Reviewed-by: Eric Blake --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org --9g9J96uGF2eX7XyD52ujBCfRhBqJaA7I6-- --ZABI0nTGYlvu8QsADX28yH8olsHEWfwf7 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEccLMIrHEYCkn0vOqp6FrSiUnQ2oFAl1AmO0ACgkQp6FrSiUn Q2ojGAf/Wx+0jE6Tp7ZCEBS74XQiHbt4WBkzRlZ82AC1XsQffadAQwgeJw+yBVnc DU8sO9T+FWBL6n00jndAdCUvIvdZD48ukRAYcssl8pbMQq3gkaNm5nQdjR4mXjoV F1/xmHr8UgAqs3AYpq3pI1soWx29OreEBFGXuSTcWGchPfIr4pYrR7u7j1D2DBdm hBCdwsUVZdsg3kD9OM8T0/Lx7hQSv2rGaDS10eBgPV1tfXf3qOhcmo/2PkhY8NXJ pe37JH4iRMl0FIRu5xuPDfsdzYodtjaXiCo+jH/FXQyPiVWAAZ2HI1lTT/sfbxRL 27KIU2+KHNMX5maxU1JEyHJ2g3kprQ== =shAT -----END PGP SIGNATURE----- --ZABI0nTGYlvu8QsADX28yH8olsHEWfwf7--