Thread: PQdb() fails with coredump when PQconnectDB() passed invalid parameter.

version 7.4.5

using postgresql-7.4.5/src/test/examples/testlibpq as follows

"testlibpq hostname=shouldHaveUsedHostNotHostname"

fails with coredump

SunOS pluto 5.9 Generic_117171-07 sun4u sparc SUNW,Ultra-5_10

On Wed, Sep 29, 2004 at 05:59:37PM +0100, Trevor Inns wrote:
> version 7.4.5
>
> using postgresql-7.4.5/src/test/examples/testlibpq as follows
>
> "testlibpq hostname=shouldHaveUsedHostNotHostname"
>
> fails with coredump
>
> SunOS pluto 5.9 Generic_117171-07 sun4u sparc SUNW,Ultra-5_10

Confirmed on Solaris 9 with PostgreSQL 8.0.0beta3 (CVS).  Here's
a stack trace:

#0  0xff1344e4 in strlen () from /usr/lib/libc.so.1
#1  0xff186bec in _doprnt () from /usr/lib/libc.so.1
#2  0xff18861c in fprintf () from /usr/lib/libc.so.1
#3  0x00010a08 in main (argc=135304, argv=0x10cd8) at testlibpq.c:44

Here's line 44:

fprintf(stderr, "Connection to database '%s' failed.\n", PQdb(conn));

PQdb() is returning NULL, which causes fprintf() to dump core.
On FreeBSD 4.10-STABLE, fprintf() handles NULL:

Connection to database '(null)' failed.
invalid connection option "hostname"

--
Michael Fuhr
http://www.fuhr.org/~mfuhr/

Michael Fuhr <mike@fuhr.org> writes:
> PQdb() is returning NULL, which causes fprintf() to dump core.

It is actually documented that a failed connection might return NULL for
this, so the example code is wrong.  I've corrected the examples to not
assume PQdb can be used on a failed connection.

pg_dump was doing it wrong too :-(

            regards, tom lane