Re: [PATCH 2/3] tests: Don't pass INT_MAX to virFileReadAll()

On 6/14/21 2:26 PM, Peter Krempa wrote: > On Mon, Jun 14, 2021 at 14:14:47 +0200, Michal Prívozník wrote: >> On 6/14/21 1:31 PM, Tim Wiederhake wrote: >>> On Mon, 2021-06-14 at 13:06 +0200, Michal Privoznik wrote: >>>> In a few occasions in tests we pass INT_MAX to >>>> virFileReadLimFD(). This is not safe because virFileReadAll() >>>> will call virFileReadLimFD() under the hood which takes the limit >>>> and adds 1 to it. >>> >>> Calling virFileReadAll with "INT_MAX - 1" looks funny. Is it possible >>> to check for "maxlen >= INT_MAX" in virFileReadLimFD instead? >> >> Actually, I don't understand why we need to add 1 in the first place. >> I'll push the other two patches and send v2 for this that removes the +1. > > It's so that it guarantees that a file of 'maxlen' length is read > completely and the terminating '\0' is in the resulting string. > > Removing the '+ 1' would change this kind of semantics, which may > require audit of all callers. > I'm not sure that's correct behaviour. I mean, if I specify that the limit should be X, then at the most X bytes should be read, not X+1. Also, virFileReadLimFD() uses saferead_lim() which upon successful return makes sure the returned string is properly terminated.