Re: [Qemu-devel] [PATCH] vl: fix possible int overflow for qemu_timedate_diff()

[Gonglei (Arei)]

> -----Original Message-----
> From: Paolo Bonzini [mailto:address@hidden
> Sent: Tuesday, February 06, 2018 11:52 PM
> To: Gonglei (Arei); address@hidden
> Cc: shenghualong
> Subject: Re: [PATCH] vl: fix possible int overflow for qemu_timedate_diff()
> 
> On 01/02/2018 12:59, Gonglei wrote:
> > From: shenghualong <address@hidden>
> >
> > When the Windows guest users set the time to year 2099,
> > the return value of qemu_timedate_diff() will overflow
> > with variable clock mode as below format:
> >
> >  <clock offset='variable' adjustment='-1201568405' basis='utc'>
> >
> > Let's change the return value of qemu_timedate_diff() from
> > int to time_t to fix the possible overflow problem.
> >
> > Signed-off-by: shenghualong <address@hidden>
> > Signed-off-by: Gonglei <address@hidden>
> 
> Thanks, this makes sense.  However, looking at the users, you should
> also change the type of:
> 
> - the diff variable in hw/timer/m48t59.c function set_alarm;
> 
> - the offset argument of the RTC_CHANGE QAPI event (to int64)
> 
> - the sec_offset and alm_sec fields of MenelausState in hw/timer/twl92230.c
> 
> - the offset argument of qemu_get_timedate.
> 
OK, will do.

Thanks,
-Gonglei

> Thanks,
> 
> Paolo
> 
> > ---
> >  include/qemu-common.h | 2 +-
> >  vl.c                  | 4 ++--
> >  2 files changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/include/qemu-common.h b/include/qemu-common.h
> > index 05319b9..6fb80aa 100644
> > --- a/include/qemu-common.h
> > +++ b/include/qemu-common.h
> > @@ -33,7 +33,7 @@ int qemu_main(int argc, char **argv, char **envp);
> >  #endif
> >
> >  void qemu_get_timedate(struct tm *tm, int offset);
> > -int qemu_timedate_diff(struct tm *tm);
> > +time_t qemu_timedate_diff(struct tm *tm);
> >
> >  #define qemu_isalnum(c)            isalnum((unsigned char)(c))
> >  #define qemu_isalpha(c)            isalpha((unsigned char)(c))
> > diff --git a/vl.c b/vl.c
> > index e517a8d..9d225da 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -146,7 +146,7 @@ int nb_nics;
> >  NICInfo nd_table[MAX_NICS];
> >  int autostart;
> >  static int rtc_utc = 1;
> > -static int rtc_date_offset = -1; /* -1 means no change */
> > +static time_t rtc_date_offset = -1; /* -1 means no change */
> >  QEMUClockType rtc_clock;
> >  int vga_interface_type = VGA_NONE;
> >  static int full_screen = 0;
> > @@ -812,7 +812,7 @@ void qemu_get_timedate(struct tm *tm, int offset)
> >      }
> >  }
> >
> > -int qemu_timedate_diff(struct tm *tm)
> > +time_t qemu_timedate_diff(struct tm *tm)
> >  {
> >      time_t seconds;
> >
> >