Re: [PATCH v1 5/5] xentrace: Implement cpu mask range parsing of human values (-C).

[George Dunlap <george.dunlap@eu.citrix.com>]

On 06/04/2014 02:44 PM, Konrad Rzeszutek Wilk wrote:
> Instead of just using -c 0x<some hex value> we can
> also use -C <starting cpu>-<end cpu> or -C <cpu1>,<cpu2>

Would it be better, I wonder, to just try to overload the -c operator, 
special-casing "0x[hex]" to use the old interface?  Anyone who's 
currently using -c should almost certainly be using a hex string there, 
I should think -- using decimal would be pretty daft.

All it would take, I think, would be to check for bytes 0 and 1 being 
"0x", and if so, calling strtoul() rather than parse_cpumask_range().

[snip]
> @@ -967,6 +970,98 @@ static int parse_cpumask(const char *arg)
>       return 0;
>   }
>
> +static int parse_cpumask_range(const char *arg)
> +{
> +    xc_cpumap_t map;
> +    unsigned int a, b, buflen = strlen(arg);
> +    int c, c_old, totaldigits, nmaskbits;
> +    int exp_digit, in_range;
> +
> +    if ( !buflen )
> +    {
> +        fprintf(stderr, "Invalid option argument: %s\n", arg);
> +        usage(); /* does exit */
> +    }
> +    nmaskbits = xc_get_max_cpus(xc_handle);
> +    if ( nmaskbits <= 0 )
> +    {
> +        fprintf(stderr, "Failed to get max number of CPUs! rc: %d\n", nmaskbits);
> +        usage();
> +    }
> +    map = xc_cpumap_alloc(xc_handle);
> +    if ( !map )
> +    {
> +        fprintf(stderr, "Out of memory!\n");
> +        usage();
> +    }
> +    c = c_old = totaldigits = 0;
> +    do {
> +        exp_digit = 1;
> +        in_range = 0;
> +        a = b = 0;
> +        while ( buflen )
> +        {
> +            c = *arg++;
> +            buflen--;
> +
> +            if ( isspace(c) )
> +                continue;

Is it possible for this to have a space at the beginning?  Doesn't 
getopt() take care of that?

> +
> +            if ( totaldigits && c && isspace(c_old) )

c_old doesn't seem to be set anywhere after it's initialized above.

> +            {
> +                fprintf(stderr, "No embedded whitespaces allowed in: %s\n", arg);
> +                goto err_out;
> +            }
> +
> +            /* A '\0' or a ',' signal the end of a cpu# or range */
> +            if ( c == '\0' || c == ',' )
> +                break;
> +
> +            if ( c == '-' )
> +            {
> +                if ( exp_digit || in_range )
> +                        goto err_out;

Isn't exp_digit a bit redundant, as if "in_range" is 1, "exp_digit" will 
also always be 1?

Everything else looks reasonable.

  -George