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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 C3F1AC432C3 for ; Thu, 28 Nov 2019 19:27:53 +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 8D90D21774 for ; Thu, 28 Nov 2019 19:27:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Dew3G0v/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8D90D21774 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]:52612 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iaPSA-0002qO-Ma for qemu-devel@archiver.kernel.org; Thu, 28 Nov 2019 14:27:50 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:38095) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iaOgT-0006EM-8x for qemu-devel@nongnu.org; Thu, 28 Nov 2019 13:38:36 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iaOg7-00089e-BU for qemu-devel@nongnu.org; Thu, 28 Nov 2019 13:38:12 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:40325 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iaOg5-0007sD-Ut for qemu-devel@nongnu.org; Thu, 28 Nov 2019 13:38:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1574966287; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=fdgt50hjQpCcnDwoPcms4KQ6G0kR/izkzJKfGW8hlVo=; b=Dew3G0v/VybL6SQLMndRRakHUrygB3zk+HpoCx+pCiVz763c7YEy4CjTgSJNfqPkeEvJVA 1xez/+l6nwXiwa4rrIVB7c0UkWaVitHyjH9oCJFjfMqCK/fRv7UM8DHegkq0HwB9ZMSfUQ PdTA8gDYfSWNtM3/r72WL9sB2AvshoA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-111-di8Dn4O8NIWDu5yr6Isx2Q-1; Thu, 28 Nov 2019 13:38:06 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 172E6107ACC4; Thu, 28 Nov 2019 18:38:05 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-116-145.ams2.redhat.com [10.36.116.145]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9912D5C1B0; Thu, 28 Nov 2019 18:38:01 +0000 (UTC) Subject: Re: [PATCH v2] qga: fence guest-set-time if hwclock not available To: Cornelia Huck , Michael Roth References: <20191128181100.23187-1-cohuck@redhat.com> From: Laszlo Ersek Message-ID: Date: Thu, 28 Nov 2019 19:38:00 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20191128181100.23187-1-cohuck@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-MC-Unique: di8Dn4O8NIWDu5yr6Isx2Q-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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: "=?UTF-8?Q?Daniel_P_._Berrang=c3=a9?=" , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi Cornelia, On 11/28/19 19:11, Cornelia Huck wrote: > The Posix implementation of guest-set-time invokes hwclock to > set/retrieve the time to/from the hardware clock. If hwclock > is not available, the user is currently informed that "hwclock > failed to set hardware clock to system time", which is quite > misleading. This may happen e.g. on s390x, which has a different > timekeeping concept anyway. > > Let's check for the availability of the hwclock command and > return QERR_UNSUPPORTED for guest-set-time if it is not available. > > Signed-off-by: Cornelia Huck > --- > > v1 (RFC) -> v2: > - use hwclock_path[] > - use access() instead of stat() > > --- > qga/commands-posix.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/qga/commands-posix.c b/qga/commands-posix.c > index 1c1a165daed8..ffb6420fa9cd 100644 > --- a/qga/commands-posix.c > +++ b/qga/commands-posix.c > @@ -156,6 +156,17 @@ void qmp_guest_set_time(bool has_time, int64_t time_ns, Error **errp) > pid_t pid; > Error *local_err = NULL; > struct timeval tv; > + const char hwclock_path[] = "/sbin/hwclock"; Did you drop the "static" storage-class specifier on purpose? > + static int hwclock_available = -1; > + > + if (hwclock_available < 0) { > + hwclock_available = (access(hwclock_path, X_OK) == 0); > + } > + > + if (!hwclock_available) { > + error_setg(errp, QERR_UNSUPPORTED); > + return; > + } > > /* If user has passed a time, validate and set it. */ > if (has_time) { > @@ -195,7 +206,7 @@ void qmp_guest_set_time(bool has_time, int64_t time_ns, Error **errp) > > /* Use '/sbin/hwclock -w' to set RTC from the system time, > * or '/sbin/hwclock -s' to set the system time from RTC. */ > - execle("/sbin/hwclock", "hwclock", has_time ? "-w" : "-s", > + execle(hwclock_path, "hwclock", has_time ? "-w" : "-s", I think it's somewhat obscure now that arg="hwclock" is supposed to match the last pathname component in hwclock_path="/sbin/hwclock". There are multiple ways to compute "arg" like that, of course. But I think they all look uglier than the above. So I'm fine if we just keep this. If you purposely dropped the "static", then: Reviewed-by: Laszlo Ersek If you just missed the "static" and now intend to add it back, then for v3: Reviewed-by: Laszlo Ersek Thanks Laszlo > NULL, environ); > _exit(EXIT_FAILURE); > } else if (pid < 0) { >