[CRIU] [PATCH 3/7] mount: use add_to_string() in attach_option()

[Pavel Emelyanov]

On 12/16/2015 11:51 PM, Stanislav Kinsburskiy wrote:
> 
> 
> 16.12.2015 18:45, Pavel Emelyanov пишет:
>> On 12/16/2015 06:33 PM, Stanislav Kinsburskiy wrote:
>>> Signed-off-by: Stanislav Kinsburskiy <skinsbursky at virtuozzo.com>
>>> ---
>>>   mount.c |   23 +++++------------------
>>>   1 file changed, 5 insertions(+), 18 deletions(-)
>>>
>>> diff --git a/mount.c b/mount.c
>>> index 0c3192a..bcb8a77 100644
>>> --- a/mount.c
>>> +++ b/mount.c
>>> @@ -1163,24 +1163,11 @@ out:
>>>   
>>>   static int attach_option(struct mount_info *pm, char *opt)
>>>   {
>>> -	char *buf;
>>> -	int len, olen;
>>> -
>>> -	len = strlen(pm->options);
>>> -	olen = strlen(opt);
>>> -	buf = xrealloc(pm->options, len + olen + 2);
>>> -	if (buf == NULL)
>>> -		return -1;
>>> -
>>> -	if (len && buf[len - 1] != ',') {
>>> -		buf[len] = ',';
>>> -		len++;
>>> -	}
>>> -
>>> -	memcpy(buf + len, opt, olen + 1);
>>> -	pm->options = buf;
>>> -
>>> -	return 0;
>>> +	if (pm->options[strlen(pm->options)-1] == ',')
>> Isn't it faster to check for pm->options[0] != '\0'?
>>
> 
> This check for "," at the end was strange. I don't really understand, 
> where it comes from.
> I though, that the intention is to not duplicate comma when adding 
> another option.
> No?

Well, the intention was not to put comma in front of the very
first option :) Like this

1st option attach : str += option
>=2nd option attach : str += ',' + option

If we always do str += ',' + option, then the string would look like
,opt1,opt2,opt3 instead or opt1,opt2,opt3

>>> +		pm->options = add_to_string(pm->options, "%s", opt);
>>> +	else
>>> +		pm->options = add_to_string(pm->options, ",%s", opt);
>>> +	return pm->options ? 0 : -1;
>>>   }
>>>   
>>>   /* Is it mounted w or w/o the newinstance option */
>>>
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>>> .
>>>
> 
> .
>