Thread

1. How to determine if a user exists..

   Dominic J. Eidson <sauron@the-infinite.org> — 2001-04-23T06:14:03Z

   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/
   
   
   

2. Re: How to determine if a user exists..

   Joel Burton <jburton@scw.org> — 2001-04-23T13:05:07Z

   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
   
   
   

3. Re: How to determine if a user exists..

   Dominic J. Eidson <sauron@the-infinite.org> — 2001-04-23T13:43:40Z

   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/
   
   
   

4. Re: How to determine if a user exists..

   Tom Lane <tgl@sss.pgh.pa.us> — 2001-04-23T14:02:27Z

   "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
   
   

5. Re: How to determine if a user exists..

   Dominic J. Eidson <sauron@the-infinite.org> — 2001-04-23T14:14:50Z

   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/
   
   
   

6. Re: Re: How to determine if a user exists..

   Peter Eisentraut <peter_e@gmx.net> — 2001-04-23T15:34:55Z

   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