[libvirt] [PATCH v2] xen: Remove PATH_MAX sized stack allocation from block stats code

[Matthias Bolte]

2011/4/10 Daniel Veillard <veillard at redhat.com>:
> On Sat, Apr 09, 2011 at 12:05:17PM +0200, Matthias Bolte wrote:
>> ---
>>  src/xen/block_stats.c |   51 +++++++++++++++++++++++++------------------------
>>  1 files changed, 26 insertions(+), 25 deletions(-)
>>
>> diff --git a/src/xen/block_stats.c b/src/xen/block_stats.c
>> index e7c80c9..1918257 100644
>> --- a/src/xen/block_stats.c
>> +++ b/src/xen/block_stats.c
>> @@ -113,34 +113,35 @@ read_stat (const char *path)
>>  }
>>
>>  static int64_t
>> -read_bd_stat (int device, int domid, const char *str)
>> +read_bd_stat(int device, int domid, const char *str)
>>  {
>> -    char path[PATH_MAX];
>> +    static const char *paths[] = {
>> +        "/sys/bus/xen-backend/devices/vbd-%d-%d/statistics/%s",
>> +        "/sys/bus/xen-backend/devices/tap-%d-%d/statistics/%s",
>> +        "/sys/devices/xen-backend/vbd-%d-%d/statistics/%s",
>> +        "/sys/devices/xen-backend/tap-%d-%d/statistics/%s"
>> +    };
>> +
>> +    int i;
>> +    char *path;
>>      int64_t r;
>>
>> -    snprintf (path, sizeof path,
>> -              "/sys/bus/xen-backend/devices/vbd-%d-%d/statistics/%s",
>> -              domid, device, str);
>> -    r = read_stat (path);
>> -    if (r >= 0) return r;
>> -
>> -    snprintf (path, sizeof path,
>> -              "/sys/bus/xen-backend/devices/tap-%d-%d/statistics/%s",
>> -              domid, device, str);
>> -    r = read_stat (path);
>> -    if (r >= 0) return r;
>> -
>> -    snprintf (path, sizeof path,
>> -              "/sys/devices/xen-backend/vbd-%d-%d/statistics/%s",
>> -              domid, device, str);
>> -    r = read_stat (path);
>> -    if (r >= 0) return r;
>> -
>> -    snprintf (path, sizeof path,
>> -              "/sys/devices/xen-backend/tap-%d-%d/statistics/%s",
>> -              domid, device, str);
>> -    r = read_stat (path);
>> -    return r;
>> +    for (i = 0; i < ARRAY_CARDINALITY(paths); ++i) {
>> +        if (virAsprintf(&path, paths[i], domid, device, str) < 0) {
>> +            virReportOOMError();
>> +            return -1;
>> +        }
>> +
>> +        r = read_stat(path);
>> +
>> +        VIR_FREE(path);
>> +
>> +        if (r >= 0) {
>> +            return r;
>> +        }
>> +    }
>> +
>> +    return -1;
>>  }
>>
>>  /* In Xenstore, /local/domain/0/backend/vbd/<domid>/<device>/state,
>
>  ACK, thanks !
>
> Daniel
>

Thanks, pushed.

Matthias