Received: (qmail 61413 invoked by uid 501); 15 Mar 2002 00:21:43 -0000
Message-Id: <20020315002142.61410.qmail@apache.org>
Date: 15 Mar 2002 00:21:42 -0000
From: Jeroen Boomgaardt <jeroen@swissclue.com>
Reply-To: jeroen@swissclue.com
To: submit@bugz.apache.org
Subject: rnd map type balancing broken
X-Send-Pr-Version: 3.110

>Number:         10185
>Category:       mod_rewrite
>Synopsis:       rnd map type balancing broken
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    apache
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   apache
>Arrival-Date:   Thu Mar 14 16:30:00 PST 2002
>Closed-Date:    Sat Mar 16 15:47:09 PST 2002
>Last-Modified:  Sat Mar 16 15:47:09 PST 2002
>Originator:     jeroen@swissclue.com
>Release:        1.3.23
>Organization:
>Environment:
Linux system1 2.4.9-31smp #1 SMP Tue Feb 26 06:55:00 EST 2002 i686 unknown
>Description:
Between 1.3.22 and 1.3.23, a change was made to one line in mod_rewrite.c:

<     return ((double)(rand() % RAND_MAX) / RAND_MAX) * (h - l + 1) + l;
---
>     return (int)((double)(rand() % RAND_MAX) / RAND_MAX) * (h - l + 1) + l;

This breaks the random balancing between the value parts in a rnd type map, at least on RedHat 7.2: it always selects the first value part.

This map type is normally used for load balancing through Apache. If such a setup is tried with Apache 1.3.23, all load will be sent to the first system.
>How-To-Repeat:
Try to use a rnd type map.
>Fix:
If the above change is reverted, i.e. remove the (int) that was added, the rnd map type will function as expected again.
>Release-Note:
>Audit-Trail:
State-Changed-From-To: open-closed
State-Changed-By: wrowe
State-Changed-When: Sat Mar 16 15:47:09 PST 2002
State-Changed-Why:

Bingo.  You hit the nail on the head, I've wrapped the
entire expression before casting to (int) for the correct
return type.

This problem should be resolved in 1.3.24 - thank you for
the report and identifying the solution!!!

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