Re: [PATCHES] Bad bug in fopen() wrapper code

Tom Lane wrote:
> "Magnus Hagander" <mha(at)sollentuna(dot)net> writes:
> > That is part of the original open() code that Claudio did back for 8.0,
> > so it has definitly been working since then.
>
> Hm, maybe best not to touch it, but still...
>
> > I haven't really read into
> > the code, though... But a qiuck look doesn't show me any place wher eit
> > does ignore O_EXCL - which combination would that be?
>
> What's bugging me is that 0 and O_EXCL give the same answer, and
> O_TRUNC and O_TRUNC | O_EXCL give the same answer, but O_CREAT and
> O_CREAT | O_EXCL give different answers, as do O_CREAT | O_TRUNC
> and O_CREAT | O_TRUNC | O_EXCL. I'm also pretty suspicious of
> both O_CREAT | O_EXCL and O_CREAT | O_TRUNC | O_EXCL giving the
> same answer. However, I have no idea what the semantics are of
> the symbols the function is mapping into, so maybe it's OK.

I am CC'ing Claudio Natoli on this question about
open.c::openFlagsToCreateFileFlags(), but in looking at the code, it
seems OK because:

o O_EXCL doesn't have any meaning unless O_CREAT is used

o O_TRUNC has no meaning when O_CREAT | O_EXCL are used
because you are guaranteed to be creating a new file

Claudio, the function is here, at the top of the file:

http://developer.postgresql.org/cvsweb.cgi/pgsql/src/port/open.c?rev=1.18;content-type=text%2Fx-cvsweb-markup

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