[Piglit] [PATCH] Fix infinite loop in piglit_is_extension_in_string.

[Paul Berry]

On 20 December 2011 08:19, Paul Berry <stereotype441 at gmail.com> wrote:

> On 20 December 2011 06:56, Brian Paul <brianp at vmware.com> wrote:
>
>> On 12/19/2011 10:46 PM, Paul Berry wrote:
>>
>>> If piglit_is_extension_in_string(**) finds an extension whose name
>>> begins with the name it is searching for, but is not equal to the name
>>> it is searching for (e.g. it is searching for EXT_transform_feedback
>>> but it finds EXT_transform_feedback2), we need it to advance by one
>>> character before restarting the search, otherwise it will loop
>>> indefinitely.
>>>
>>> Prevents a hang when running some transform feedback tests on nVidia's
>>> proprietary Linux driver.
>>> ---
>>>  tests/util/piglit-util.c |   16 ++++++++++++----
>>>  1 files changed, 12 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/tests/util/piglit-util.c b/tests/util/piglit-util.c
>>> index 65b02f5..3241528 100644
>>> --- a/tests/util/piglit-util.c
>>> +++ b/tests/util/piglit-util.c
>>> @@ -145,15 +145,23 @@ bool piglit_is_extension_in_string(**const char
>>> *haystack, const char *needle)
>>>        if (needle_len == 0)
>>>                return false;
>>>
>>> -       while (haystack != NULL) {
>>> +       while (true) {
>>>                const char *const s = strstr(haystack, needle);
>>>
>>> -               if (s != NULL
>>> -               &&  (s[needle_len] == ' ' || s[needle_len] == '\0')) {
>>> +               if (s == NULL)
>>> +                       return false;
>>> +
>>> +               if (s[needle_len] == ' ' || s[needle_len] == '\0') {
>>>                        return true;
>>>                }
>>>
>>> -               haystack = s;
>>> +               /* strstr found an extension whose name begins with
>>> +                * needle, but whose name is not equal to needle.
>>> +                * Restart the search at s + 1 so that we don't just
>>> +                * find the same extension again and go into an
>>> +                * infinite loop.
>>> +                */
>>> +               haystack = s + 1;
>>>
>>
>> Actually, I think you could do "haystack = s + needle_len" but it's no
>> big deal.
>>
>
> Oh yeah.  That's a better idea.
>
>
>>
>>         }
>>>
>>>        return false;
>>>
>>
>> -Brian
>>
>
>
Just double checked on my nVidia system, and "haystack = s + needle_len"
works fine, as expected.  Brian, can I take that as a "reviewed by" if I
make that change?
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