potential bug in "xm atropos" implementation

potential bug in "xm atropos" implementation

[Diwaker Gupta]

>From tools/libxc/xc_atropos.c:

int xc_atropos_domain_set(int xc_handle,
                          u32 domid, u64 period, u64 slice, u64 latency,
                          int xtratime)

which takes 6 arguments

>From tools/python/xen/xm/main.py:
class ProgAtropos(Prog):
<snip>
    def main(self, args):
        if len(args) != 5: self.err("%s: Invalid argument(s)" % args[0])
        dom = args[1]
        v = map(int, args[2:5])
        server.xend_domain_cpu_atropos_set(dom, *v)

Now if you specify all 6 arguments on the command line, xm atropos
fails with "Invalid arguments" due to the above code. If you give 5
arguments, ProgAtropos fails since the corresponding libxc function
call takes 6 arguments.

Following patch will fix it:
Index: main.py
===================================================================
--- main.py     (revision 185)
+++ main.py     (working copy)
@@ -579,9 +579,9 @@
         print "\nSet atropos parameters."

     def main(self, args):
-        if len(args) != 5: self.err("%s: Invalid argument(s)" % args[0])
+        if len(args) != 6: self.err("%s: Invalid argument(s)" % args[0])
         dom = args[1]
-        v = map(int, args[2:5])
+        v = map(int, args[2:6])
         server.xend_domain_cpu_atropos_set(dom, *v)

 xm.prog(ProgAtropos)

-- 
Diwaker Gupta
http://resolute.ucsd.edu/diwaker


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Re: potential bug in "xm atropos" implementation

[Christian Limpach]

On Mon, Oct 18, 2004 at 03:21:38PM -0700, Diwaker Gupta wrote:
> From tools/libxc/xc_atropos.c:
> 
> int xc_atropos_domain_set(int xc_handle,
>                           u32 domid, u64 period, u64 slice, u64 latency,
>                           int xtratime)
> 
> which takes 6 arguments
> 
> From tools/python/xen/xm/main.py:
> class ProgAtropos(Prog):
> <snip>
>     def main(self, args):
>         if len(args) != 5: self.err("%s: Invalid argument(s)" % args[0])
>         dom = args[1]
>         v = map(int, args[2:5])
>         server.xend_domain_cpu_atropos_set(dom, *v)
> 
> Now if you specify all 6 arguments on the command line, xm atropos
> fails with "Invalid arguments" due to the above code. If you give 5
> arguments, ProgAtropos fails since the corresponding libxc function
> call takes 6 arguments.

No, the 6th argument you see in the xc_atropos_domain_set function
signature (i.e. the function's 1st argument -- xc_handle) is added
in the Pyhton<->xc interface function pyxc_atropos_domain_set
(in tools/python/xen/lowlevel/xc/xc.c).

    christian



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Re: potential bug in "xm atropos" implementation

[Diwaker Gupta]

> No, the 6th argument you see in the xc_atropos_domain_set function
> signature (i.e. the function's 1st argument -- xc_handle) is added
> in the Pyhton<->xc interface function pyxc_atropos_domain_set
> (in tools/python/xen/lowlevel/xc/xc.c).

I see. Basically I was running into this problem:

$ xm help atropos
<lists FIVE params>

$ xm atropos 1 30 100 10 1 <FIVE params>
Error: atropos: Invalid argument(s)

$ xm atropos 1 30 100 10 <FOUR params>
Traceback (most recent call last):
  File "/usr/sbin/xm", line 6, in ?
    main.main(sys.argv)
  File "/usr/lib/python2.3/site-packages/xen/xm/main.py", line 786, in main
    xm.main(args)
  File "/usr/lib/python2.3/site-packages/xen/xm/main.py", line 105, in main
    self.main_call(args)
  File "/usr/lib/python2.3/site-packages/xen/xm/main.py", line 123, in main_call
    p.main(args[1:])
  File "/usr/lib/python2.3/site-packages/xen/xm/main.py", line 585, in main
    server.xend_domain_cpu_atropos_set(dom, *v)
TypeError: xend_domain_cpu_atropos_set() takes exactly 6 arguments (5 given)

-- 
Diwaker Gupta
http://resolute.ucsd.edu/diwaker


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Re: potential bug in "xm atropos" implementation

[Christian Limpach]

On Mon, Oct 18, 2004 at 04:30:48PM -0700, Diwaker Gupta wrote:
> > No, the 6th argument you see in the xc_atropos_domain_set function
> > signature (i.e. the function's 1st argument -- xc_handle) is added
> > in the Pyhton<->xc interface function pyxc_atropos_domain_set
> > (in tools/python/xen/lowlevel/xc/xc.c).
> 
> I see. Basically I was running into this problem:

ah I see, now your patch makes sense ;-)  args[2:5] does (confusingly)
not include the 5th element and len (of course) counts from 0.  The 6th
argument which xend_domain_cpu_atropos_set expects (its 1st) is not
the 1st argument for xc_atropos_domain_set though...

I've applied your patch...  Thanks!

    christian



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