Thread: How to determine if a user exists..
I am trying to add another authentication mechanism to PostgreSQL... And, in doing that, I need to verify the existance of an user within PG. Short of hacking together code from verify_password(), is there any way to check if a user exists in postgresql? (The actuall password verification will be taken care of elsewhere... I just need to check if the user exists.) thanks, -- Dominic J. Eidson "Baruk Khazad! Khazad ai-menu!" - Gimli ------------------------------------------------------------------------------- http://www.the-infinite.org/ http://www.the-infinite.org/~dominic/
On Mon, 23 Apr 2001, Dominic J. Eidson wrote: > I am trying to add another authentication mechanism to PostgreSQL... And, > in doing that, I need to verify the existance of an user within PG. Short > of hacking together code from verify_password(), is there any way to check > if a user exists in postgresql? (The actuall password verification will be > taken care of elsewhere... I just need to check if the user exists.) pg_user holds users (passwords in pg_shadow) HTH, -- Joel Burton <jburton@scw.org> Director of Information Systems, Support Center of Washington
On Mon, 23 Apr 2001, Joel Burton wrote: > pg_user holds users > > (passwords in pg_shadow) I doubt the -hackers people would let me add SPI_* stuff into libpq, just to retrieve whether a user exists or not.. My first thought was to check the existance of users against $PGDATA/pg_pwd... One question I'd have there, is whether pg_pwd always exists (or, can be relied upon existing.)? -- Dominic J. Eidson "Baruk Khazad! Khazad ai-menu!" - Gimli ------------------------------------------------------------------------------- http://www.the-infinite.org/ http://www.the-infinite.org/~dominic/
On Mon, 23 Apr 2001, Tom Lane wrote: > If you're trying to do this from the postmaster, I think the only way is > to look at $PGDATA/global/pg_pwd, which is a flat-file version of > pg_shadow. This is what I thought - thanks. -- Dominic J. Eidson "Baruk Khazad! Khazad ai-menu!" - Gimli ------------------------------------------------------------------------------- http://www.the-infinite.org/ http://www.the-infinite.org/~dominic/
"Dominic J. Eidson" <sauron@the-infinite.org> writes:
> I am trying to add another authentication mechanism to PostgreSQL... And,
> in doing that, I need to verify the existance of an user within PG. Short
> of hacking together code from verify_password(), is there any way to check
> if a user exists in postgresql?
If you're trying to do this from the postmaster, I think the only way is
to look at $PGDATA/global/pg_pwd, which is a flat-file version of
pg_shadow.
You'd be well advised to study the existing verification mechanisms in
src/backend/libpq/.
regards, tom lane
Dominic J. Eidson writes: > On Mon, 23 Apr 2001, Joel Burton wrote: > > > pg_user holds users > > > > (passwords in pg_shadow) > > I doubt the -hackers people would let me add SPI_* stuff into libpq, just > to retrieve whether a user exists or not.. You wouldn't have to do that. There are better ways to read system tables in the backend. See FAQ_DEV. > My first thought was to check > the existance of users against $PGDATA/pg_pwd... One question I'd have > there, is whether pg_pwd always exists (or, can be relied upon existing.)? No it doesn't and no you can't. The best way to verify a user's existence in the context of a new authentication method is to not do that at all. None of the other methods do it, the existence of a user is checked when authentication has completed and the backend starts. -- Peter Eisentraut peter_e@gmx.net http://funkturm.homeip.net/~peter