[libvirt] [PATCHv2 1/3] xen_vm: convert to typesafe virConf accessors

[Fabiano Fidêncio]

On Sun, May 27, 2018 at 11:55 AM, Ján Tomko <jtomko at redhat.com> wrote:
> On Sat, May 26, 2018 at 11:00:25PM +0200, Fabiano Fidêncio wrote:
>>
>> From: Fabiano Fidêncio <fidencio at redhat.com>
>>
>> Signed-off-by: Fabiano Fidêncio <fabiano at fidencio.org>
>
>
> The S-o-B address should match the one of the author.

Fixed, thanks!

>
>> ---
>> src/xenconfig/xen_xm.c | 268
>> ++++++++++++++++++++++++-------------------------
>> 1 file changed, 132 insertions(+), 136 deletions(-)
>>
>> diff --git a/src/xenconfig/xen_xm.c b/src/xenconfig/xen_xm.c
>> index 4becb40b4c..fc88ac8238 100644
>> --- a/src/xenconfig/xen_xm.c
>> +++ b/src/xenconfig/xen_xm.c
>> @@ -112,172 +112,168 @@ xenParseXMDisk(virConfPtr conf, virDomainDefPtr
>> def)
>> {
>>     virDomainDiskDefPtr disk = NULL;
>>     int hvm = def->os.type == VIR_DOMAIN_OSTYPE_HVM;
>> -    virConfValuePtr list = virConfGetValue(conf, "disk");
>> +    char **disks = NULL, **entries;
>>
>
>> -    if (list && list->type == VIR_CONF_LIST) {
>> -        list = list->list;
>
>
> Adding
>    else
>        list = NULL;
>
> Would let you move the while below outside of the if body and separate
> the whitespace changes from the virConfGetValue -> StringList change.
>
> Or, even better, the whole per-disk logic can be moved to a separate
> function.

Right, makes sense.

>
>
>> -        while (list) {
>
>
>> -            char *head;
>> -            char *offset;
>> -            char *tmp;
>> -            const char *src;
>> +    if (virConfGetValueStringList(conf, "disk", false, &disks) < 0)
>> +        goto cleanup;
>>
>> -            if ((list->type != VIR_CONF_STRING) || (list->str == NULL))
>> -                goto skipdisk;
>> +    for (entries = disks; *entries; entries++) {
>> +        char *head = *entries;
>> +        char *offset;
>> +        char *tmp;
>> +        const char *src;
>>
>> -            head = list->str;
>> -            if (!(disk = virDomainDiskDefNew(NULL)))
>> -                return -1;
>> +        if (!(disk = virDomainDiskDefNew(NULL)))
>> +            return -1;
>> +
>> +        /*
>> +         * Disks have 3 components, SOURCE,DEST-DEVICE,MODE
>> +         * eg, phy:/dev/HostVG/XenGuest1,xvda,w
>> +         * The SOURCE is usually prefixed with a driver type,
>> +         * and optionally driver sub-type
>> +         * The DEST-DEVICE is optionally post-fixed with disk type
>> +         */
>> +
>> +        /* Extract the source file path*/
>> +        if (!(offset = strchr(head, ',')))
>> +            goto skipdisk;
>
>
> Using a separate function would also get rid of this unusual label.

Right.

>
>> +
>> +        if (offset == head) {
>> +            /* No source file given, eg CDROM with no media */
>> +            ignore_value(virDomainDiskSetSource(disk, NULL));
>> +        } else {
>> +            if (VIR_STRNDUP(tmp, head, offset - head) < 0)
>> +                goto cleanup;
>> +
>> +            if (virDomainDiskSetSource(disk, tmp) < 0) {
>> +                VIR_FREE(tmp);
>> +                goto cleanup;
>> +            }
>> +            VIR_FREE(tmp);
>> +        }
>>
>
> [...]
>
>> -            skipdisk:
>> -            list = list->next;
>> -            virDomainDiskDefFree(disk);
>> -            disk = NULL;
>> -        }
>> +        skipdisk:
>> +        virDomainDiskDefFree(disk);
>> +        disk = NULL;
>>     }
>>
>>     return 0;
>>
>>  cleanup:
>> +    virStringListFree(disks);
>
>
> The list needs to be freed even in the success path.

True!

>
> (NB: this usage of 'cleanup' label is not customary -
> for code paths returning an error, we use 'error'.
> 'cleanup' is meant for code shared between the success
> and error paths)

Aha! Okay, I've decided to follow the "most used" label in the file
that had the same intention.
I'll adopt your suggestion and we can slowly get rid of the non
customary labels whenever touching the old code.

>
> Jano


Thanks for the review!
-- 
Fabiano Fidêncio