Fix for Win32 division involving INT_MIN - Mailing list pgsql-patches

With no Win32 exception detection code in sight, I propose the following
patch to prevent server crashes for unusual INT_MIN integer division.

One interesting thing is that int4div already has code that a check for
a similar division on all platforms, but _after_ the division, rather
than before.

---------------------------------------------------------------------------

Magnus Hagander wrote:
> Confirmed here.
>
> What we get is Integer Overflow, on the instruction "idiv esi" in postgres!int4div+0x1f. (Per windows debugger.) Same
doesnot happen on Linux. 
>
> Tom - hints? ;-) Any idea why this happens on win32 but not linux?
>
> //Magnus
>
> > -----Original Message-----
> > From: pgsql-bugs-owner@postgresql.org
> > [mailto:pgsql-bugs-owner@postgresql.org] On Behalf Of Wang Haiyong
> > Sent: Wednesday, April 05, 2006 4:34 AM
> > To: pgsql-bugs@postgresql.org
> > Subject: [BUGS] Bug in window xp
> >
> > Version(8.1.3)
> > Bug in window xp:
> >
> > C:\Documents and Settings\openbase>pg_ctl start
> > LOG:  database system was shut down at 2006-4-04 15:54:43 ??????
> > LOG:  checkpoint record is at 0/38C2E0
> > LOG:  redo record is at 0/38C2E0; undo record is at 0/0; shutdown TRUE
> > LOG:  next transaction ID: 569; next OID: 24576
> > LOG:  next MultiXactId: 1; next MultiXactOffset: 0
> > LOG:  database system is ready
> > LOG:  transaction ID wrap limit is 2147484146, limited by
> > database "postgres"
> >
> > C:\Documents and Settings\openbase>
> > C:\Documents and Settings\openbase>
> > C:\Documents and Settings\openbase>
> > C:\Documents and Settings\openbase>psql
> > Welcome to psql 8.1.3, the PostgreSQL interactive terminal.
> >
> > Type:  \copyright for distribution terms
> >        \h for help with SQL commands
> >        \? for help with psql commands
> >        \g or terminate with semicolon to execute query
> >        \q to quit
> >
> > openbase=# SELECT (-2147483648) / (-1);
> > LOG:  server process (PID 3760) was terminated by signal 21
> > LOG:  terminating any other active server processes
> > LOG:  all server processes terminated; reinitializing
> > ???????????
> >         ???????????????????
> > ???????????????
> > ??????????. ????: LOG:  database system was interrupted at
> > 2006-0-05 08:39:56 ??????
> > LOG:  checkpoint record is at 0/38C2E0
> > LOG:  redo record is at 0/38C2E0; undo record is at 0/0; shutdown TRUE
> > LOG:  next transaction ID: 569; next OID: 24576
> > LOG:  next MultiXactId: 1; next MultiXactOffset: 0
> > LOG:  database system was not properly shut down; automatic
> > recovery in progres
> >
> > FATAL:  the database system is starting up
> > ??.
> > !> LOG:  record with zero length at 0/38C328
> > LOG:  redo is not required
> > LOG:  database system is ready
> > LOG:  transaction ID wrap limit is 2147484146, limited by
> > database "postgres"
> >
> >
> >
> > ???
> > ???????????
> >
> > ?????????????????????? A1?
> > ???110179
> > ???024?83661905
> > ?????www.neusoft.com
> >
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--
  Bruce Momjian   http://candle.pha.pa.us
  EnterpriseDB    http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +
Index: src/backend/utils/adt/int.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/utils/adt/int.c,v
retrieving revision 1.72
diff -c -c -r1.72 int.c
*** src/backend/utils/adt/int.c    11 Mar 2006 01:19:22 -0000    1.72
--- src/backend/utils/adt/int.c    8 Jun 2006 21:04:23 -0000
***************
*** 770,775 ****
--- 770,786 ----
                  (errcode(ERRCODE_DIVISION_BY_ZERO),
                   errmsg("division by zero")));

+ #ifdef WIN32
+     /*
+      *    Win32 doesn't throw a catchable exception for
+      *    SELECT -2147483648 /* INT_MIN */ / (-1);
+      */
+     if (arg2 == -1 && arg1 == INT_MIN)
+         ereport(ERROR,
+                 (errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+                  errmsg("integer out of range")));
+ #endif
+
      result = arg1 / arg2;

      /*