[libvirt] [PATCH 17/25] utils: Add a helper to get the device name that sg device mapped to

[Osier Yang]

On 07/05/13 22:00, John Ferlan wrote:
> On 05/03/2013 02:07 PM, Osier Yang wrote:
>> E.g.
>>
>> % sg_map
>> /dev/sg0  /dev/sda
>> /dev/sg1  /dev/sr0
>>
>> What the helper gets for /dev/sg0 is /dev/sda, it will be used by
>> later patch.
>> ---
>>   src/libvirt_private.syms |  1 +
>>   src/util/virscsi.c       | 47 +++++++++++++++++++++++++++++++++++++++++++++++
>>   src/util/virscsi.h       |  4 ++++
>>   3 files changed, 52 insertions(+)
>>
>> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
>> index fa59c14..8a7105c 100644
>> --- a/src/libvirt_private.syms
>> +++ b/src/libvirt_private.syms
>> @@ -1692,6 +1692,7 @@ virSCSIDeviceFileIterate;
>>   virSCSIDeviceFree;
>>   virSCSIDeviceGetAdapter;
>>   virSCSIDeviceGetBus;
>> +virSCSIDeviceGetDevName;
>>   virSCSIDeviceGetName;
>>   virSCSIDeviceGetReadonly;
>>   virSCSIDeviceGetSgName;
>> diff --git a/src/util/virscsi.c b/src/util/virscsi.c
>> index 7d3d40e..f337c75 100644
>> --- a/src/util/virscsi.c
>> +++ b/src/util/virscsi.c
>> @@ -143,6 +143,53 @@ cleanup:
>>       return sg;
>>   }
>>   
>> +/* Returns device name (e.g. "sdc") on success, or NULL
>> + * on failure.
>> + */
>> +char *
>> +virSCSIDeviceGetDevName(const char *adapter,
>> +                        unsigned int bus,
>> +                        unsigned int target,
>> +                        unsigned int unit)
>> +{
>> +    DIR *dir = NULL;
>> +    struct dirent *entry;
>> +    char *path = NULL;
>> +    char *name = NULL;
>> +    unsigned int adapter_id;
>> +
>> +    if (virSCSIDeviceGetAdapterId(adapter, &adapter_id) < 0)
>> +        return NULL;
>> +
>> +    if (virAsprintf(&path,
>> +                    SYSFS_SCSI_DEVICES "/%d:%d:%d:%d/block",
>> +                    adapter_id, bus, target, unit) < 0) {
>> +        virReportOOMError();
>> +        return NULL;
>> +    }
>> +
>> +    if (!(dir = opendir(path))) {
>> +        virReportError(VIR_ERR_INTERNAL_ERROR,
>> +                       _("Failed to open %s"), path);
>> +        goto cleanup;
>> +    }
>> +
>> +    while ((entry = readdir(dir))) {
>> +        if (entry->d_name[0] == '.')
>> +            continue;
>> +
>> +        if (!(name = strdup(entry->d_name))) {
>> +            virReportOOMError();
>> +            goto cleanup;
>> +        }
> If 'name' then what - we go back to the top of the loop and if there's
> more entries then we'll strdup() another name....  Although I have to
> wonder if there can be more than non hidden entry in the list...  Makes
> me wonder about my earlier reviews which didn't think about the loop
> exit (that is virSCSIDeviceGetSgName())

It's the only one entry (except the hidden entries), same for
virSCSIDeviceGetSgName. But adding the "break" is better,
to avoid it loops 1 more. Will change when pushing.

Thanks.