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=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 8B9F1C432C0 for ; Thu, 28 Nov 2019 12:50:29 +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 54DB8208E4 for ; Thu, 28 Nov 2019 12:50:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Hlr27X9M" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 54DB8208E4 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]:48658 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iaJFb-0000sl-Ht for qemu-devel@archiver.kernel.org; Thu, 28 Nov 2019 07:50:28 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:53953) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iaJB8-00079E-Od for qemu-devel@nongnu.org; Thu, 28 Nov 2019 07:45:53 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iaJB4-0004Hh-Ac for qemu-devel@nongnu.org; Thu, 28 Nov 2019 07:45:47 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:51794 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iaJB4-0004BL-4L for qemu-devel@nongnu.org; Thu, 28 Nov 2019 07:45:46 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1574945144; h=from:from:reply-to: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=hFYk46yR4pubyIuF4vfzAO4EN9UVTzlSg0yarn5xADI=; b=Hlr27X9MseQpq5iE3WXwTNnZy0RvtfHUn8ua4yq/wZUiguPUgicxdjNllAZn44HcJcZU/O HvcdrjniFruiZ771+jqirIFIJ9GPLxjeW+vJ0JbE72d5LBC/TnXgm1wUYMlK356IQ7LBL6 aynM7Rb6DPYu//PDGDWLgULrY4tx+l4= 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-30-qs8wqYC9Poi-rtBJOK3xww-1; Thu, 28 Nov 2019 07:45:36 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 31474800D41; Thu, 28 Nov 2019 12:45:35 +0000 (UTC) Received: from redhat.com (unknown [10.42.16.105]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6664A100164D; Thu, 28 Nov 2019 12:45:34 +0000 (UTC) Date: Thu, 28 Nov 2019 12:45:32 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Cornelia Huck Subject: Re: [PATCH RFC] qga: fence guest-set-time if hwclock not available Message-ID: <20191128124532.GF248361@redhat.com> References: <20191128123658.28351-1-cohuck@redhat.com> MIME-Version: 1.0 In-Reply-To: <20191128123658.28351-1-cohuck@redhat.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-MC-Unique: qs8wqYC9Poi-rtBJOK3xww-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.120 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Michael Roth , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Nov 28, 2019 at 01:36:58PM +0100, 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. >=20 > Let's check for the availability of the hwclock command and > return QERR_UNSUPPORTED for guest-set-time if it is not available. >=20 > Signed-off-by: Cornelia Huck > --- >=20 > Not sure if that is the correct approach, but the current error > message is really quite confusing. I guess the alternative is to just #ifndef __s390x__ the whole impl of the qmp_guest_set_time method, but I don't have a strong opinion on which is best. >=20 > Gave it a quick test with an s390x and an x86_64 guest; invoking > 'virsh domtime ' now fails with 'not currently supported' > on s390x and continues to work as before on x86_64. >=20 > --- > qga/commands-posix.c | 20 +++++++++++++++++++- > 1 file changed, 19 insertions(+), 1 deletion(-) >=20 > diff --git a/qga/commands-posix.c b/qga/commands-posix.c > index 1c1a165daed8..bd298a38b716 100644 > --- a/qga/commands-posix.c > +++ b/qga/commands-posix.c > @@ -149,6 +149,13 @@ int64_t qmp_guest_get_time(Error **errp) > return tq.tv_sec * 1000000000LL + tq.tv_usec * 1000; > } > =20 > +static int check_hwclock_available(const char *path) > +{ > + struct stat st; > + > + return (stat(path, &st) < 0) ? 0 : 1; > +} > + > void qmp_guest_set_time(bool has_time, int64_t time_ns, Error **errp) > { > int ret; > @@ -156,6 +163,17 @@ void qmp_guest_set_time(bool has_time, int64_t time_= ns, Error **errp) > pid_t pid; > Error *local_err =3D NULL; > struct timeval tv; > + const char *hwclock_path =3D "/sbin/hwclock"; > + static int hwclock_available =3D -1; > + > + if (hwclock_available < 0) { > + hwclock_available =3D check_hwclock_available(hwclock_path); Could do this inline with: hwclock_available =3D (access(hwclock_available, X_OK) =3D=3D 0); getting a slightly better result as this check for it being executable as well as existing. > + } > + > + if (!hwclock_available) { > + error_setg(errp, QERR_UNSUPPORTED); > + return; > + } > =20 > /* If user has passed a time, validate and set it. */ > if (has_time) { > @@ -195,7 +213,7 @@ void qmp_guest_set_time(bool has_time, int64_t time_n= s, Error **errp) > =20 > /* 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", > NULL, environ); > _exit(EXIT_FAILURE); > } else if (pid < 0) { > --=20 > 2.21.0 >=20 >=20 Regards, Daniel --=20 |: https://berrange.com -o- https://www.flickr.com/photos/dberrange= :| |: https://libvirt.org -o- https://fstop138.berrange.com= :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange= :|