Re: [Qemu-devel] [Xen-devel] [XEN][RFC PATCH V2 11/17] xc: modify save/restore to support multiple device models

[Julien Grall]

On 08/23/2012 02:27 PM, Ian Campbell wrote:
> > @@ -103,6 +103,9 @@ static ssize_t rdexact(xc_interface *xch, struct 
> > restore_ctx *ctx,
> >   #else
> >   #define RDEXACT read_exact
> >   #endif
> > +
> > +#define QEMUSIG_SIZE 21
> > +
> >   /*
> >   ** In the state file (or during transfer), all page-table pages are
> >   ** converted into a 'canonical' form where references to actual mfns
> > @@ -467,7 +522,7 @@ static int buffer_tail_hvm(xc_interface *xch, struct 
> > restore_ctx *ctx,
> >                              int vcpuextstate, uint32_t vcpuextstate_size)
> >   {
> >       uint8_t *tmp;
> > -    unsigned char qemusig[21];
> > +    unsigned char qemusig[QEMUSIG_SIZE + 1];
> >      
> An extra + 1 here?
>    
QEMUSIG_SIZE doesn't take into account the '\0'. So we need to add 1.
If an error occurred, without +1, the output log lost the last character.

> [...]
>    
> > -    qemusig[20] = '\0';
> > +    qemusig[QEMUSIG_SIZE] = '\0';
> >      
> This is one bigger than it used to be now.
>
> Perhaps this is an unrelated bug fix (I haven't check the real length of
> the sig), in which case please can you split it out and submit
> separately?
>    

#define QEMU_SIGNATURE "DeviceModelRecord0002"
Just checked, the length seems to be 21. I will send a patch with
this change.

--
Julien