Re: strncpy is not a safe version of strcpy - Mailing list pgsql-hackers

David Rowley escribió:
> On Fri, Nov 15, 2013 at 12:33 PM, Tomas Vondra <tv@fuzzy.cz> wrote:

> > Be careful with 'Name' data type - it's not just a simple string buffer.
> > AFAIK it needs to work with hashing etc. so the zeroing is actually needed
> > here to make sure two values produce the same result. At least that's how
> > I understand the code after a quick check - for example this is from the
> > same jsonfuncs.c you mentioned:
> >
> >     memset(fname, 0, NAMEDATALEN);
> >     strncpy(fname, NameStr(tupdesc->attrs[i]->attname), NAMEDATALEN);
> >     hashentry = hash_search(json_hash, fname, HASH_FIND, NULL);
> >
> > So the zeroing is on purpose, although if strncpy does that then the
> > memset is probably superflous.

This code should probably be using namecpy().  Note namecpy() doesn't
memset() after strncpy() and has survived the test of time, which
strongly suggests that the memset is indeed superfluous.

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Álvaro Herrera                http://www.2ndQuadrant.com/
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