PQsetdbLogin bug?
Sometimes PQfinish() does not return forever in the following program.
conn = PQsetdbLogin();
if(PQstatus(conn) == CONNECTION_BAD)
{
PQfinish(conn); /* blocks here */
}
PQfinish calls closePGconn that call pqPuts. pqPuts calls select(2)
and it never returns if a connection associated with the socket is not
established.
This could happend if the connection is not established, but the
socket is still opened by PQsetdbLogin. Possible fixes are:
1) close the socket in PQsetdbLogin if it is in a situation being
returns CONNECTION_BAD
case PGRES_POLLING_WRITING:
if (pqWait(0, 1, conn))
{
conn->status = CONNECTION_BAD;
close(conn->sock); <-- add this
conn->sock == -1; <-- add this
return 0;
}
break;
2) check if the status of handle returned PQsetdbLogin is
CONNECTION_BAD closePGconn. if so, do not call pqPuts (and
pqFlush)
change this:
if (conn->sock >= 0)
to:
if (conn->status != CONNECTION_BAD && conn->sock >= 0)
any thoughts?
--
Tatsuo Ishii
Tatsuo Ishii <t-ishii@sra.co.jp> writes:
2) check if the status of handle returned PQsetdbLogin is
CONNECTION_BAD closePGconn. if so, do not call pqPuts (and
pqFlush)
I like this approach. The other way, you'd have to be sure that all
failure paths close the socket before returning; even if you get it
right today, somebody will break it again in future. The sending of
the final 'X' is really quite optional anyhow, so I'd say it's fine
not to do it when there's any question about whether it's safe.
regards, tom lane
Tatsuo Ishii <t-ishii@sra.co.jp> writes:
2) check if the status of handle returned PQsetdbLogin is
CONNECTION_BAD closePGconn. if so, do not call pqPuts (and
pqFlush)I like this approach. The other way, you'd have to be sure that all
failure paths close the socket before returning; even if you get it
right today, somebody will break it again in future. The sending of
the final 'X' is really quite optional anyhow, so I'd say it's fine
not to do it when there's any question about whether it's safe.
done.
--
Tatsuo Ishii