From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:55166) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UCQii-0005qr-Ec for qemu-devel@nongnu.org; Mon, 04 Mar 2013 03:26:05 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UCQig-00047m-9Y for qemu-devel@nongnu.org; Mon, 04 Mar 2013 03:26:04 -0500 Received: from e28smtp08.in.ibm.com ([122.248.162.8]:52984) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UCQif-00046m-O2 for qemu-devel@nongnu.org; Mon, 04 Mar 2013 03:26:02 -0500 Received: from /spool/local by e28smtp08.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 4 Mar 2013 13:52:02 +0530 Received: from d28relay01.in.ibm.com (d28relay01.in.ibm.com [9.184.220.58]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id A4AA3125804E for ; Mon, 4 Mar 2013 13:56:50 +0530 (IST) Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay01.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r248Povt23199784 for ; Mon, 4 Mar 2013 13:55:50 +0530 Received: from d28av04.in.ibm.com (loopback [127.0.0.1]) by d28av04.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r248PrXv018293 for ; Mon, 4 Mar 2013 19:25:53 +1100 Message-ID: <51345A8C.2070007@linux.vnet.ibm.com> Date: Mon, 04 Mar 2013 16:25:48 +0800 From: Lei Li MIME-Version: 1.0 References: <1362130380-1895-1-git-send-email-lilei@linux.vnet.ibm.com> <1362130380-1895-3-git-send-email-lilei@linux.vnet.ibm.com> <5130E782.7080204@redhat.com> In-Reply-To: <5130E782.7080204@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 2/2] 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 03/02/2013 01:38 AM, Eric Blake wrote: > On 03/01/2013 02:33 AM, Lei Li wrote: >> Signed-off-by: Lei Li >> --- >> qga/commands-posix.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++ >> qga/qapi-schema.json | 27 ++++++++++++++++++++++++++ >> 2 files changed, 82 insertions(+) >> >> diff --git a/qga/commands-posix.c b/qga/commands-posix.c >> index f159e25..e246a0d 100644 >> --- a/qga/commands-posix.c >> +++ b/qga/commands-posix.c >> @@ -135,6 +135,61 @@ int64_t qmp_guest_get_time(Error **errp) >> return time_ns; >> } >> >> +void qmp_guest_set_time(int64_t time_ns, Error **errp) >> +{ >> + int ret; >> + int status; >> + pid_t pid; >> + Error *local_err = NULL; >> + struct timeval tv; >> + >> + /* year-2038 will overflow in case time_t is 32bit */ >> + if ((sizeof(time_t) <= 4) && ((unsigned long) time_ns & (1ul << 31))) { > Wrong. If 'unsigned long' and 'time_t' are both 32 bits, but time_ns is > 0x1000000000000000, then the cast truncates to 0 and you don't report > overflow. Conversely, if time_ns is 0x80000000, you report overflow, > even though this value fits in 32-bit time_t after you do division from > nanoseconds back to seconds. What you WANT is: Yes, you are right.. thanks. > > if (time_ns / 1000000000 != (time_t)(time_ns / 1000000000)) { > >> + error_setg_errno(errp, errno, "Invalid time %ld for overflow", >> + time_ns); > That wording sounds awkward. Worse, errno is NOT set to anything sane, > so you do NOT want error_setg_errno. And %ld is wrong for int64_t on > 32-bit platforms. How about: > > error_setg(errp, "Time %" PRI64D " is too large", time_ns); Sure, will address it as the your later reply. >> +++ b/qga/qapi-schema.json >> @@ -99,6 +99,33 @@ >> 'returns': 'int' } >> >> ## >> +# @guest-set-time: >> +# >> +# Set guest time. >> +# >> +# Right now, when a guest is paused or migrated to a file > s/Right now, when/When/ > >> +# 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. >> +# >> +# @time: time of nanoseconds, relative to the Epoch of >> +# 1970-01-01 in UTC/GMT. > drop '/GMT' > >> +# >> +# Returns: Nothing on success. >> +# >> +# Since: 1.5 >> +## >> +{ 'command': 'guest-set-time', >> + 'data': { 'time': 'int' } } >> + >> +## >> # @GuestAgentCommandInfo: >> # >> # Information about guest agent commands. >> -- Lei