From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:53946) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TtZY4-0001Mw-B6 for qemu-devel@nongnu.org; Fri, 11 Jan 2013 03:01:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TtZY2-0001ff-HQ for qemu-devel@nongnu.org; Fri, 11 Jan 2013 03:01:08 -0500 Received: from e28smtp09.in.ibm.com ([122.248.162.9]:57918) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TtZY1-0001fW-Sl for qemu-devel@nongnu.org; Fri, 11 Jan 2013 03:01:06 -0500 Received: from /spool/local by e28smtp09.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 11 Jan 2013 13:30:05 +0530 Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by d28dlp02.in.ibm.com (Postfix) with ESMTP id 711E13940053 for ; Fri, 11 Jan 2013 13:30:58 +0530 (IST) Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay01.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r0B80t1345088794 for ; Fri, 11 Jan 2013 13:30:56 +0530 Received: from d28av05.in.ibm.com (loopback [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r0B80uRK029683 for ; Fri, 11 Jan 2013 19:00:57 +1100 Message-ID: <50EFC6B3.1070104@linux.vnet.ibm.com> Date: Fri, 11 Jan 2013 16:00:51 +0800 From: Lei Li MIME-Version: 1.0 References: <1357466820-12860-1-git-send-email-lilei@linux.vnet.ibm.com> <1357466820-12860-4-git-send-email-lilei@linux.vnet.ibm.com> <50EB4BAC.7060908@redhat.com> In-Reply-To: <50EB4BAC.7060908@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 3/3] qga: add guest-set-time command List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake Cc: aliguori@us.ibm.com, qemu-devel@nongnu.org, mdroth@linux.vnet.ibm.com On 01/08/2013 06:26 AM, Eric Blake wrote: > On 01/06/2013 03:07 AM, Lei Li wrote: >> Signed-off-by: Lei Li >> --- >> qga/commands-posix.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++++++ >> qga/qapi-schema.json | 32 ++++++++++++++++++++++++++++ >> 2 files changed, 89 insertions(+), 0 deletions(-) >> >> diff --git a/qga/commands-posix.c b/qga/commands-posix.c >> index 190199d..7fff49a 100644 >> --- a/qga/commands-posix.c >> +++ b/qga/commands-posix.c >> @@ -121,6 +121,63 @@ struct HostTimeInfo *qmp_guest_get_time(Error **errp) >> return host_time; >> } >> >> +void qmp_guest_set_time(bool has_seconds, int64_t seconds, >> + bool has_microseconds, int64_t microseconds, >> + bool has_utc_offset, int64_t utc_offset, Error **errp) >> +{ >> + int ret; >> + int status; >> + pid_t pid, rpid; >> + struct timeval tv; >> + HostTimeInfo *host_time; >> + >> + if ((!has_seconds) && (!has_microseconds) && (!has_utc_offset)) { > Is it really qemu style to parenthesize this much? > >> + host_time = get_host_time(); >> + if (!host_time) { >> + error_set(errp, QERR_QGA_COMMAND_FAILED, "Failed to set guest time"); >> + return; >> + } >> + tv.tv_sec = host_time->seconds; >> + tv.tv_usec = host_time->microseconds; >> + } else if (has_seconds && has_microseconds && has_utc_offset) { >> + tv.tv_sec = (time_t) seconds + utc_offset; > You need to worry about overflow on hosts where time_t is 32-bits but > the user passed time using 64-bits (such as past the year 2038). > Likewise, it might be worth bounds-checking utc-offset to be at most 12 > hours away from UTC (or is there a better bounds?). > >> + tv.tv_usec = (time_t) microseconds; > Likewise, you should range-validate that microseconds does not overflow > 1000000 (or, if you take my suggestion about using nanoseconds, since > struct timespec is a bit more expressive, then bound things by > 1000000000, and properly round when converting to lower resolution > interfaces such as settimeofday()). > >> + } else { >> + error_set(errp, QERR_INVALID_PARAMETER, "parameter missing"); > That's a bit harsh. I'm thinking it might be nicer to support: > > all three missing - grab time from the host > at least seconds present - populate any missing subseconds or utc_offset > as 0 > seconds missing, but other fields present - error > > making this look more like: > > if (!has_seconds) { > if (has_subseconds || has_utc_offset) { > error_set(); > } else { > use get_host_time(); > } > } else { > tv.tv_sec = seconds + (has_utc_offset ? utc_offset : 0); > ... > } Good suggestions! Yes, I know this is harsh. I will improve it in next version, as well as the document. >> +++ b/qga/qapi-schema.json >> @@ -117,6 +117,38 @@ >> 'returns': 'HostTimeInfo' } >> >> ## >> +# @guest-set-time: >> +# >> +# Set guest time. If none arguments were given, will set > s/none/no/ > >> +# host time to guest. >> +# >> +# Right now, when a guest is paused or migrated to a file >> +# then loaded from that file, the guest OS has no idea that >> +# there was a big gap in the time. Depending on how long >> +# the gap was, NTP might not be able to resynchronize the >> +# guest. >> +# >> +# This command tries to set guest time based on the information >> +# from host or an absolute value given by management app, and >> +# set the Hardware Clock to the current System Time. This >> +# will make it easier for a guest to resynchronize without >> +# waiting for NTP. >> +# >> +# @seconds: #optional "seconds" time. >> +# >> +# @microseconds: #optional "microseconds" time. >> +# >> +# @utc-offset: #optional utc offset. > If you like my above suggestions, this might be worth documenting that > @microseconds (or @nanoseconds) must not be provided unless @seconds is > present, and so on. > > > Same questions as in patch 1/3 - you need to document what @seconds is > relative to (presumably the Epoch of 1970-01-01), and what format > utc-offset takes. Based on this patch, it looks like you are using > utc-offset as the number of seconds difference, so one hour is > represented as 3600. Sure. About the utc-offset format, I have replied to the previous patch. It would be one-hour offset, and it's my mistake here...:( > -- Lei