[libvirt] [PATCH v2 2/4] util: virhostcpu: factor out frequency parsing

[Pino Toscano]

On Wednesday, 13 December 2017 17:10:19 CET Andrea Bolognani wrote:
> From: Bjoern Walk <bwalk at linux.vnet.ibm.com>
> 
> All different architectures use the same copy-pasted code to parse
> processor frequency information from /proc/cpuinfo. Let's extract that
> code into a function to avoid repetition.
> 
> We now also tolerate if the parsing of /proc/cpuinfo is not successful
> and just report a warning instead of bailing out and abandoning the rest
> of the CPU information.
> 
> Reviewed-by: Marc Hartmayer <mhartmay at linux.vnet.ibm.com>
> Reviewed-by: Boris Fiuczynski <fiuczy at linux.vnet.ibm.com>
> Reviewed-by: Andrea Bolognani <abologna at redhat.com>
> Signed-off-by: Bjoern Walk <bwalk at linux.vnet.ibm.com>
> ---
> [...]
> +static int
> +virHostCPUParseFrequency(FILE *cpuinfo,
> +                         virArch arch,
> +                         unsigned int *mhz)
> +{
> +    const char *prefix = NULL;
> +    char line[1024];
> +
> +    if (ARCH_IS_X86(arch))
> +        prefix = "cpu MHz";
> +    else if (ARCH_IS_PPC(arch))
> +        prefix = "clock";
> +    else if (ARCH_IS_ARM(arch))
> +        prefix = "BogoMIPS";
> +
> +    if (!prefix) {
> +        VIR_WARN("Parser for /proc/cpuinfo needs to be adapted for your architecture");
> +        return 1;

I'd print the architecture in the warning, so sysadmins can see easily
which architecture it is, even when looking at logs collected from
different libvirt installations.

> +    while (fgets(line, sizeof(line), cpuinfo) != NULL) {
> +        if (!STRPREFIX(line, prefix))
> +            continue;

IMHO here it would be a good idea to check that line[strlen(prefix)]
is either a space or ':', to avoid prefix matching more keys than the
actual intended one(s) -- something like:

  char c = line[strlen(prefix)];
  if (c != ':' && !c_isspace(*str))
    continue;

-- 
Pino Toscano
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: This is a digitally signed message part.
URL: <http://listman.redhat.com/archives/libvir-list/attachments/20171213/66da1249/attachment-0001.sig>