Do not allow short reads.

[bbockelm]

Proposed fix for https://sft.its.cern.ch/jira/browse/ROOT-3341

@smithdh - can you review?

[smithdh]

Hi Brian,

Thanks for the patch. I think the length returned by Read in ReadBuffer(char *,Int_t) should also be checked too, so I'll also change as well a adding your patch.

These changes are in the older xroot plugin. In the newer plugin, TNetXNGFile, the Read() result is checked for a bad status, and the status of the individual chunks from VectorRead() are also checked. A length mismatch is a part of the validity check in the client, so short reads shouldn't be possible there.

[smithdh]

Beg your pardon; there is a possibility of a short read in TNetXNGFile::Read(char*,Long64_t,Int_t). I will also add a check here.

[smithdh]

Hi. I've added the patch.
Thank you.