[libvirt] [PATCH 10/11] util: Add a util to guess the scsi host name with specified "parent"

[Osier Yang]

On 20/06/13 02:53, John Ferlan wrote:
> On 06/07/2013 01:03 PM, Osier Yang wrote:
>> Not really guessing, it returns host name of the scsi host which has
>> smallest unique_id.
>> ---
>>   src/libvirt_private.syms |   1 +
>>   src/util/virutil.c       | 122 +++++++++++++++++++++++++++++++++++++++++++++++
>>   src/util/virutil.h       |   4 ++
>>   tests/utiltest.c         |  27 +++++++++++
>>   4 files changed, 154 insertions(+)
>>
>> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
>> index 27fb0b5..ec85079 100644
>> --- a/src/libvirt_private.syms
>> +++ b/src/libvirt_private.syms
>> @@ -1948,6 +1948,7 @@ virGetUserDirectory;
>>   virGetUserID;
>>   virGetUserName;
>>   virGetUserRuntimeDirectory;
>> +virGuessStableScsiHostName;
>>   virHexToBin;
>>   virIndexToDiskName;
>>   virIsCapableFCHost;
>> diff --git a/src/util/virutil.c b/src/util/virutil.c
>> index a80574f..7f36e27 100644
>> --- a/src/util/virutil.c
>> +++ b/src/util/virutil.c
>> @@ -2256,6 +2256,120 @@ cleanup:
>>       }
>>       return ret;
>>   }
>> +
>> +static int
>> +virGuessStableScsiHostNameCallback(const char *fpath,
>> +                                   void *opaque)
>> +{
>> +    const char *filename = opaque;
>> +    char *p = NULL;
>> +
>> +    p = strrchr(fpath, '/');
>> +    p++;
>> +
>> +    if (STREQ(p, filename))
>> +        return 0;
>> +    return -1;
>> +}
>> +
>> +/**
>> + * virGuessStableScsiHostName:
>> + * @sysfs_prefix: The directory path where starts to traverse, defaults
>> + *                to SYSFS_BUS_PCI_DEVICES.
>> + * @addr: The parent's PCI address
>> + *
>> + * Returns the host name (e.g. host10) of the scsi host whose parent
>> + * has address @addr, and "unique_id" has the smallest value on success.
>> + * Or NULL on failure.
> It is up to the caller to free the memory returned.

Yes, will add

>
>> + */
>> +char *
>> +virGuessStableScsiHostName(const char *sysfs_prefix,
>> +                           const char *address)
>> +{
>> +    const char *prefix = sysfs_prefix ? sysfs_prefix : SYSFS_BUS_PCI_DEVICES;
>> +    unsigned int flags = 0;
>> +    char **paths = NULL;
>> +    int npaths = 0;
>> +    char *smallest_path = NULL;
>> +    unsigned int smallest;
>> +    char *dir = NULL;
>> +    char *buf = NULL;
>> +    char *p1 = NULL;
>> +    char *p2 = NULL;
>> +    char *ret = NULL;
>> +    int i;
>> +
>> +    const char *filename = "unique_id";
>> +
>> +    if (virAsprintf(&dir, "%s/%s", prefix, address) < 0) {
>> +        virReportOOMError();
>> +        return NULL;
>> +    }
>> +
>> +    flags |= (VIR_TRAVERSE_DIRECTORY_IGNORE_HIDDEN_FILES |
>> +              VIR_TRAVERSE_DIRECTORY_FALL_THROUGH);
>> +
>> +    if ((npaths = virTraverseDirectory(dir, 4, flags,
>> +                                       virGuessStableScsiHostNameCallback,
>> +                                       NULL, (void *)filename, &paths)) < 0)
>> +        goto cleanup;
>> +
>  From here...
>
>> +    smallest_path = paths[0];
>> +    if (virFileReadAll(paths[0], 1024, &buf) < 0)
>> +        goto cleanup;
>> +
>> +    if ((p1 = strchr(buf, '\n')))
>> +        *p1 = '\0';
>> +
>> +    if (virStrToLong_ui(buf, NULL, 10, &smallest) < 0)
>> +        goto cleanup;
>> +
>> +    VIR_FREE(buf);
>> +    buf = NULL;
> ...to here isn't necessary... and if you keep it, then the loop below
> goes from 1 to npaths since 0 is already covered...

Hm, stupid mistake...  Thanks.

Osier