From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:37438) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UFs0L-00040y-E4 for qemu-devel@nongnu.org; Wed, 13 Mar 2013 16:10:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UFs0H-0000pN-4D for qemu-devel@nongnu.org; Wed, 13 Mar 2013 16:10:29 -0400 Received: from mail-yh0-x22e.google.com ([2607:f8b0:4002:c01::22e]:57537) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UFs0H-0000p5-0Q for qemu-devel@nongnu.org; Wed, 13 Mar 2013 16:10:25 -0400 Received: by mail-yh0-f46.google.com with SMTP id q15so249794yhf.33 for ; Wed, 13 Mar 2013 13:10:24 -0700 (PDT) Sender: fluxion Date: Wed, 13 Mar 2013 15:07:52 -0500 From: mdroth Message-ID: <20130313200752.GE4005@vm> References: <1363169431-1561-1-git-send-email-lilei@linux.vnet.ibm.com> <1363169431-1561-2-git-send-email-lilei@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1363169431-1561-2-git-send-email-lilei@linux.vnet.ibm.com> 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: lilei@linux.vnet.ibm.com Cc: aliguori@us.ibm.com, qemu-devel@nongnu.org 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? > + 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(). > + 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) > + > + 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 >