Re: PostgreSQL X/Open Socket / BSD Socket Issue on HP-UX

On 22.09.2011 13:51, MUHAMMAD ASIF wrote:
> You are right, _xpg_ socket functionality is not available in older systems, it is available in hp-ux 11.23 version through patch HCO_35744 . HPUX 10.20 is very old machine (1996). I am using latest HPUX B.11.31 machine, I don't have access to older systems. -D_XOPEN_SOURCE_EXTENDED make the postgres build X/Open Socket enabled including connector's i.e libpq. Now if system default 64bit perl (BSD Socket) try to use libpq (X/Open Socket) it will end up in unexpected results or errors . HP-UX don't allow mixing of X/Open Socket objects and BSD Socket objects in the same 64bit binary, HP tried to fix this issue through -D_HPUX_ALT_XOPEN_SOCKET_API on later version of OS. It seems nice that if postgres adopt this fix at least for connectors (PFA patch, minor change in src/interfaces/libpq/Makefile) and so that users on later hp-ux boxes don't trouble with these socket issues  and connect their applications to database server with the help of libpq without the fear of X/Open So
cket or BSD Socket complexity. On older system defining _HPUX_ALT_XOPEN_SOCKET_API should do no effects or issues.

You're right that defining _HPUX_ALT_XOPEN_SOCKET_API should have no 
effect on older systems that don't have that. But removing -lxnet and 
-D_XOPEN_SOURCE_EXTENDED *is* clearly going to cause problems on older 
systems.

According to 
http://docstore.mik.ua/manuals/hp-ux/en/B2355-60130/xopen_networking.7.html, 
-D_XOPEN_SOURCE_EXTENDED should still be defined, even if you use 
-D_HPUX_ALT_XOPEN_SOCKET_API. So removing that was bogus. But -lxnet 
should indeed not be used with _HPUX_ALT_XOPEN_SOCKET_API, so I think we 
need a configure test to see whether that option is available, and use 
it only if it is.

Looking at the headers, it seems pretty hard to detect whether 
_HPUX_ALT_XOPEN_SOCKET_API is available. The best I can think of is to 
check whether the _xpg_* functions exist. That's a bit ugly because a 
program is not supposed to call those functions directly, but it should 
work fine in practice, so attached is a patch to do that.

I did some experiments on my HP-UX box ("HP-UX guest2 B.11.31 U ia64 
HP-UX", according to uname -a). I built a small test program that uses 
libpq, and also calls socket() and getsockopt() on an unrelated socket. 
I also tested a little perl function in the database, that calls 
getsockopt(). Without this patch, the perl function fails, and the test 
program fails unless compiled with "-lxnet -D_XOPEN_SOURCE_EXTENDED" 
(ie. unless it uses X/Open sockets). With the patch, the perl function 
works, and the test program works, whether it's compiled with X/Open or not.

In the patch, I had to move the logic into configure.in, because the 
autoconf AC_* macros can't be used in the template, which is a plain 
shell script.

Unforunately I don't have access to any older HP-UX boxes that don't 
have _HPUX_ALT_XOPEN_SOCKET_API. Tom, can you test this on that old 
HP-UX box of yours?

-- 
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com