Re: [Qemu-devel] [PATCH v2 6/8] monitor: New argument type 'T'

[Luiz Capitulino <lcapitulino@redhat.com>]

On Thu, 21 Jan 2010 14:54:51 +0100
Markus Armbruster <armbru@redhat.com> wrote:

> Luiz Capitulino <lcapitulino@redhat.com> writes:
> 
> > On Wed, 20 Jan 2010 17:08:20 +0100
> > Markus Armbruster <armbru@redhat.com> wrote:
> >
> >> This is a double value with optional suffixes ms, us, ns.  We'll need
> >> this to get migrate_set_downtime() QMP-ready.
> >> 
> >> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> >> ---
> >>  monitor.c |   16 +++++++++++++++-
> >>  1 files changed, 15 insertions(+), 1 deletions(-)
> >> 
> >> diff --git a/monitor.c b/monitor.c
> >> index ce97e7b..6dafe0b 100644
> >> --- a/monitor.c
> >> +++ b/monitor.c
> >> @@ -75,6 +75,9 @@
> >>   *              user mode accepts an optional G, g, M, m, K, k suffix,
> >>   *              which multiplies the value by 2^30 for suffixes G and
> >>   *              g, 2^20 for M and m, 2^10 for K and k
> >> + * 'T'          double
> >> + *              user mode accepts an optional ms, us, ns suffix,
> >> + *              which divides the value by 1e3, 1e6, 1e9, respectively
> >>   * '/'          optional gdb-like print format (like "/10x")
> >>   *
> >>   * '?'          optional type (for all types, except '/')
> >> @@ -3544,6 +3547,7 @@ static const mon_cmd_t *monitor_parse_command(Monitor *mon,
> >>              }
> >>              break;
> >>          case 'b':
> >> +        case 'T':
> >>              {
> >>                  double val;
> >>  
> >> @@ -3558,7 +3562,7 @@ static const mon_cmd_t *monitor_parse_command(Monitor *mon,
> >>                  if (get_double(mon, &val, &p) < 0) {
> >>                      goto fail;
> >>                  }
> >> -                if (*p) {
> >> +                if (c == 'b' && *p) {
> >>                      switch (*p) {
> >>                      case 'K': case 'k':
> >>                          val *= 1 << 10; p++; break;
> >> @@ -3568,6 +3572,16 @@ static const mon_cmd_t *monitor_parse_command(Monitor *mon,
> >>                          val *= 1 << 30; p++; break;
> >>                      }
> >>                  }
> >> +                if (c == 'T' && p[0] && p[1] == 's') {
> >
> >  Is this indexing of 'p' really correct? What if the value you're interested
> > is at the of the string? Like:
> >
> > .args_type = "str:s,value:b"
> 
> p points right behind the floating-point number.  If no characters
> follow, it points to the string's terminating zero.  If exactly one
> character follows, it points to that one, and the next one is the
> terminating zero.  If more than one follow, p points to the first one.
> 
> "p[0] && p[1] == 's'" is safe, because p[0] is safe, and if p[0] != 0,
> then p[1] is also safe.
> 
> Convinced?

 Yes, looks fine.

> 
> >> +                    switch (*p) {
> >> +                    case 'm':
> >> +                        val /= 1e3; p += 2; break;
> >> +                    case 'u':
> >> +                        val /= 1e6; p += 2; break;
> >> +                    case 'n':
> >> +                        val /= 1e9; p += 2; break;
> >> +                    }
> >> +                }
> >>                  if (*p && !qemu_isspace(*p)) {
> >>                      monitor_printf(mon, "Unknown unit suffix\n");
> >>                      goto fail;