get username of user calling function?

am Thu, dem 01.03.2007, um 11:40:11 -0500 mailte George Nychis folgendes:

Hi,

Is it possible to get the username of the user calling a function?

You can use the current_user - variable. Select current_user;

Andreas
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Andreas Kretschmer
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A. Kretschmer wrote:

You can use the current_user - variable. Select current_user;

I'm trying to create a function in which users can only kill their own processes, it works
perfectly if i hardcode a username in such as this:
CREATE FUNCTION kill_process(integer) RETURNS boolean
AS 'select pg_cancel_backend(procpid)
FROM (SELECT procpid FROM pg_stat_activity WHERE procpid=$1 and usename=''gnychis'')
AS kill;'
LANGUAGE SQL SECURITY DEFINER;

But if i try to replace usename=''gnychis'' with usename=current_user it no longer works.

Any ideas?

- George

On 3/1/07, George Nychis <gnychis@cmu.edu> wrote:

A. Kretschmer wrote:

You can use the current_user - variable. Select current_user;

I'm trying to create a function in which users can only kill their own
processes, it works
perfectly if i hardcode a username in such as this:
CREATE FUNCTION kill_process(integer) RETURNS boolean
AS 'select pg_cancel_backend(procpid)
FROM (SELECT procpid FROM pg_stat_activity WHERE procpid=$1 and
usename=''gnychis'')
AS kill;'
LANGUAGE SQL SECURITY DEFINER;

See the EXECUTE function in the pl/pgSQL language in the docs for dynamic
queries.

But if i try to replace usename=''gnychis'' with usename=current_user it no

David Legault wrote:

See the EXECUTE function in the pl/pgSQL language in the docs for dynamic
queries.

So it turns out that in a SECURITY DEFINER the current_user is the owner of the function.
I had to use session_user and it works now :)

- George

On 3/1/07, George Nychis <gnychis@cmu.edu> wrote:

David Legault wrote:

See the EXECUTE function in the pl/pgSQL language in the docs for

dynamic

queries.

So it turns out that in a SECURITY DEFINER the current_user is the owner
of the function.
I had to use session_user and it works now :)

yes because you are running it in the context of the owner of the function

there is also another SECURITY setting that will be in the context of the
caller where current_user() should return the callee.

- George