Re: [PATCH 2/2] posix: Remove alloca usage for internal fnmatch implementation

[Florian Weimer]

* Adhemerval Zanella:

> On 08/03/2021 09:59, Florian Weimer wrote:
>> * Adhemerval Zanella via Libc-alpha:
>> 
>>> -    else if (*p == L_('|'))
>>> +    else if (*p == L_(')') || *p == L_('|'))
>>>        {
>>>          if (level == 0)
>>>            {
>>> -            NEW_PATTERN;
>>> -            startp = p + 1;
>>> +            size_t slen = opt == L_('?') || opt == L_('@')
>>> +                     ? pattern_len : p - startp + 1;
>>> +            CHAR *newp = malloc (slen * sizeof (CHAR));
>>> +            if (newp != NULL)
>>> +              {
>>> +                *((CHAR *) MEMPCPY (newp, startp, p - startp)) = L_('\0');
>>> +                PASTE (PATTERN_PREFIX,_add) (&list, newp);
>>> +              }
>>> +            if (newp == NULL || PASTE (PATTERN_PREFIX, _has_failed) 
>>> (&list))
>>> +              {
>>> +                retval = -2;
>>> +                goto out;
>>> +              }
>>> +
>>> +            if (*p == L_('|'))
>>> +              startp = p + 1;
>>>            }
>> 
>> slen seems to be the wrong variable name.  But I don't know wh the
>> original code computes plen conditionally and then uses p - startp
>> unconditionally.  That seems wrong.  The discrepancy goes back to
>> 821a6bb4360.  Do you see a case where the difference matters?
>> 
>> The == 0 checks for the recursive FCT calls are wrong because they treat
>> match failure the same as OOM and other errors (the -2 return value),
>> but that also is a pre-existing issue.
>> 
>> The conversation itself appears to be faithful.
>
> Hi Florian,
>
> I noted this patch [1] is marked accepted, was you the one that
> accepted it? In any case, are you still ok with the change?
>
>
> [1] 
> https://patchwork.sourceware.org/project/glibc/patch/20210202130804.1920933-2-adhemerval.zanella@linaro.org/

I think all the issues I identified are pre-existing, and as I said, the
conversion to remove alloca appears to be correct.

Thanks,
Florian