Re: [PATCH] printf: more error handling

[Chet Ramey]

On 2/2/24 6:33 PM, Grisha Levit wrote:
> On Thu, Feb 1, 2024 at 7:41 PM Chet Ramey <chet.ramey@case.edu> wrote:
> > On 1/22/24 9:44 PM, Grisha Levit wrote:
> > > The size of the buffer used for printf -v is tracked in an int but this
> > > can overflow since the buffer can be built up by multiple vsnprintf(3)
> > > calls, each of which can append up to INT_MAX bytes to the buffer:
> >
> > Thanks for the report and patch.
>
> Thanks, a small question -- in your commit[1] you added an ferror check here:

No, I just left it in.

>     177       nw = vflag ? vbprintf (f, func) : printf (f, func); \
>     178     if (nw < 0 || ferror (stdout)) \
>     179       { \
>
> Is it necessary to check the error indicator if printf(3) just had a non-
> negative return? 

I think printf is allowed to set the error flag that ferror checks even if
it returns 0, but I could be convinced otherwise.


> And, if so, can this check be, as elsewhere:
> `(vflag == 0 && ferror (stdout))'?  I think `printf -v' should work no
> matter what the state of stdout is, no?

Sure.

--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/

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