From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:51121) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UG1Vk-0007N6-Ta for qemu-devel@nongnu.org; Thu, 14 Mar 2013 02:19:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UG1Vj-0005lX-Jo for qemu-devel@nongnu.org; Thu, 14 Mar 2013 02:19:32 -0400 Received: from e28smtp07.in.ibm.com ([122.248.162.7]:38407) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UG1Vi-0005lD-V7 for qemu-devel@nongnu.org; Thu, 14 Mar 2013 02:19:31 -0400 Received: from /spool/local by e28smtp07.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 14 Mar 2013 11:45:46 +0530 Received: from d28relay03.in.ibm.com (d28relay03.in.ibm.com [9.184.220.60]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id E1473125804E for ; Thu, 14 Mar 2013 11:50:18 +0530 (IST) Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r2E6J8Rw50331660 for ; Thu, 14 Mar 2013 11:49:09 +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 r2E6JDY4013432 for ; Thu, 14 Mar 2013 17:19:13 +1100 Message-ID: <51416BD4.5030504@linux.vnet.ibm.com> Date: Thu, 14 Mar 2013 14:19:00 +0800 From: Lei Li MIME-Version: 1.0 References: <1363169431-1561-1-git-send-email-lilei@linux.vnet.ibm.com> <1363169431-1561-2-git-send-email-lilei@linux.vnet.ibm.com> <20130313200752.GE4005@vm> In-Reply-To: <20130313200752.GE4005@vm> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 1/2] qga: add windows implementation for guest-get-time List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: mdroth Cc: aliguori@us.ibm.com, qemu-devel@nongnu.org On 03/14/2013 04:07 AM, mdroth wrote: > On Wed, Mar 13, 2013 at 06:10:30PM +0800, lilei@linux.vnet.ibm.com wrote: >> From: Lei Li >> >> Signed-off-by: Lei Li >> --- >> qga/commands-win32.c | 32 ++++++++++++++++++++++++++++++++ >> 1 files changed, 32 insertions(+), 0 deletions(-) >> >> diff --git a/qga/commands-win32.c b/qga/commands-win32.c >> index 7e8ecb3..0a2bb34 100644 >> --- a/qga/commands-win32.c >> +++ b/qga/commands-win32.c >> @@ -22,6 +22,12 @@ >> #define SHTDN_REASON_FLAG_PLANNED 0x80000000 >> #endif >> >> +/* multiple of 100 nanoseconds elapsed between windows baseline >> + (1/1/1601) and Unix Epoch (1/1/1970), accounting for leap years */ >> +#define W32_FT_OFFSET (10000000ULL * 60 * 60 * 24 * \ >> + (365 * (1970 - 1601) + \ >> + (1970 - 1601) / 4 - 3)) >> + >> static void acquire_privilege(const char *name, Error **err) >> { >> HANDLE token; >> @@ -108,6 +114,32 @@ void qmp_guest_shutdown(bool has_mode, const char *mode, Error **err) >> } >> } >> >> +int64_t qmp_guest_get_time(Error **errp) >> +{ >> + SYSTEMTIME *ts = g_malloc0(sizeof(SYSTEMTIME)); > Don't we need to free this at some point? > Sorry, my fault here... >> + int64_t time_ns; >> + union { >> + UINT64 ns100; >> + FILETIME tf; >> + } time; >> + >> + GetSystemTime(ts); >> + if (!ts) { >> + slog("guest-get-time failed: %d", GetLastError()); > GetSystemTime() does not seem to set an error that can be retrieved by > GetLastError(). Yes, you are right. >> + error_setg_errno(errp, errno, "Failed to get time"); >> + return -1; >> + } >> + >> + if (!SystemTimeToFileTime(ts, &time.tf)) { >> + error_setg_errno(errp, errno, "Failed to convert system time"); >> + return -1; >> + } >> + >> + time_ns = (int64_t)((time.ns100 - W32_FT_OFFSET) * 100); > I'm not sure how safe this union stuff is. The documentation suggests that in > some circumstances the low/high fields in FILETIME might be padded for > 64-bit alignment and that doing this type of cast could generate an > alignment fault: > > http://msdn.microsoft.com/en-us/library/windows/desktop/ms724284(v=vs.85).aspx > > or it might, perhaps even worse, just silently report the wrong time. > > I think we should just do the math explicitly: > > (((tf.dwHighDateTime << 32) | tf.dwLowDateTime) - W32_FT_OFFSET) * 100) > > (or something along that line) OK, thanks. >> + >> + return time_ns; >> +} >> + >> int64_t qmp_guest_file_open(const char *path, bool has_mode, const char *mode, Error **err) >> { >> error_set(err, QERR_UNSUPPORTED); >> -- >> 1.7.7.6 >> -- Lei