Re: Crash on attempt to connect to nonstarted server

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Magnus Hagander <magnus(at)hagander(dot)net>
Cc: PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Crash on attempt to connect to nonstarted server
Date: 2010-12-16 15:20:44
Message-ID: 201012161520.oBGFKid09101@momjian.us
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Magnus Hagander wrote:
> I get a crash on win32 when connecting to a server that's not started.
> In fe-connect.c, we have:
>
> display_host_addr = (conn->pghostaddr == NULL) &&
> (strcmp(conn->pghost, host_addr) != 0);
>
> In my case, conn->pghost is NULL at this point, as is
> conn->pghostaddr. Thus, it crashes in strcmp().

I have researched this with Magnus, and was able to reproduce the
failure. It happens only on Win32 because that is missing unix-domain
sockets so "" maps to localhost, which is an IP address. I have applied
the attached patch. The new output is:

$ psql test
psql: could not connect to server: Connection refused
Is the server running on host "???" and accepting
TCP/IP connections on port 5432?

Note the "???". This happens because the mapping of "" to localhost
happens below the libpq library variable level.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +

Attachment Content-Type Size
/pgpatches/win32 text/x-diff 856 bytes

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