Re: [Qemu-devel] [PATCH v5 5/9] qemu-log: support simple pid substitution in logfile

["Alex Bennée" <alex.bennee@linaro.org>]

Eric Blake <eblake@redhat.com> writes:

> On 02/04/2016 03:26 PM, Richard Henderson wrote:
>> On 02/05/2016 01:56 AM, Alex Bennée wrote:
>>> +    if (g_strrstr(filename, "%d")) {
>>> +        /* if we are going to format this we'd better validate first */
>>> +        if (g_regex_match_simple("^[^%]+%d[^%]+$", filename, 0, 0)) {
>>
>> Why g_strrstr instead of strstr?  There should be only one, so why look
>> for the last?

Yeah, my fault for using the glib functions, I guess
g_strstr_len(filename, -1, "%d") would be the glib equivalent for
strstr.

> For that matter, why use a heavyweight regex, when you can achieve the
> same validation with the faster:
>
> char *tmp = strchr(filename, '%');
> if (tmp) {
>     if (tmp[1] != 'd' || strchr(tmp + 2, '%')) {
>         ...report invalid string
>     }

For option parsing I'm not too worried about speed. At least a regex
gives the explicit format we expect (for those that read regex). I guess
I can do it manually if preferred.

--
Alex Bennée