[libvirt] [PATCH RFC 4/7] libxl: implement virDomainBlockStats

[Daniel P. Berrange]

On Tue, Sep 08, 2015 at 09:27:27AM +0100, Joao Martins wrote:
> diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
> index dc83083..fd952a3 100644
> --- a/src/libxl/libxl_driver.c
> +++ b/src/libxl/libxl_driver.c
>  static int
> +libxlDiskPathMatches(const char *virtpath, const char *devtype,
> +                     int *index_r, int max_index,
> +                     int *partition_r, int max_partition)
> +{
> +    const char *p;
> +    char *ep;
> +    int tl, c;
> +    long pl;
> +
> +    tl = strlen(devtype);
> +    if (memcmp(virtpath, devtype, tl))
> +        return 0;

Nit-pick, we prefer use of STREQLEN / STRNEQLEN instead
of memcmp, whenever comparing strings.

> +
> +    /* We decode the drive letter as if it were in base 52
> +     * with digits a-zA-Z, more or less */
> +    *index_r = -1;
> +    p = virtpath + tl;
> +    for (;;) {
> +        c = *p++;
> +        if (c >= 'a' && c <= 'z') {
> +            c -= 'a';
> +        } else {
> +            --p;
> +            break;
> +        }
> +        (*index_r)++;
> +        (*index_r) *= 26;
> +        (*index_r) += c;
> +
> +        if (*index_r > max_index)
> +            return 0;
> +    }
> +
> +    if (!*p) {
> +        *partition_r = 0;
> +        return 1;
> +    }
> +
> +    if (*p == '0')
> +        return 0; /* leading zeroes not permitted in partition number */
> +
> +    if (virStrToLong_l(p, &ep, 10, &pl) < 0)
> +        return 0;
> +
> +    if (pl > max_partition || *ep)
> +        return 0;
> +
> +    *partition_r = pl;
> +    return 1;
> +}

IIUC, the virDiskNameToIndex() method could do the disk part
of this, but doesn't provide the partition info. I think it
would be desirable to extend that common method to provide
partition info too, as it is conceptually useful elsewhere.

Regards,
Daniel
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