Received: (qmail 10346 invoked by uid 2012); 10 Feb 1999 21:25:37 -0000
Message-Id: <19990210212537.10345.qmail@hyperreal.org>
Date: 10 Feb 1999 21:25:37 -0000
From: Jeff Lewis <lewis@stanford.edu>
Reply-To: lewis@stanford.edu
To: apbugs@hyperreal.org
Subject: RewriteLock doesn't work for virtual hosts and silently fails
X-Send-Pr-Version: 3.2

>Number:         3874
>Category:       mod_rewrite
>Synopsis:       RewriteLock doesn't work for virtual hosts and silently fails
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    apache
>State:          closed
>Class:          sw-bug
>Submitter-Id:   apache
>Arrival-Date:   Wed Feb 10 13:30:02 PST 1999
>Last-Modified:  Tue Aug  3 11:17:33 PDT 1999
>Originator:     lewis@stanford.edu
>Organization:
>Release:        1.3.3
>Environment:
SunOS wdev 5.5.1 Generic_103640-14 sun4u sparc SUNW,Ultra-1
gcc version 2.8.1
>Description:
The lock file is opened during the init_child() phase and the file pointer is
saved in that server_rec, but that config info isn't propagated to the virtual 
host config.  Since the file pointer isn't available, even though locking is 
turned on, no locking is done and no warning is given and things break.
>How-To-Repeat:
Add a logging line to rewritelock_alloc() like

    if (conf->rewritelockfp != -1) {
        fd_lock(r, conf->rewritelockfp);
    } else if (conf->rewritelockfile) {
      ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_ALERT, r,
                   "mod_rewrite: Don't have lockfile descriptor, can't lock");
    }

then use RewriteLock and RewriteMap inside and outside of a virtual host
and you'll see that the lockfile fp isn't available through the virtual
host config, so no locking is done.
>Fix:
I moved the
        rewritelock_open(s, p);
call from the init_child() function to the server for loop in 
init_module() where the rewritelog open is as well, and that seems
to have fixed it.
>Audit-Trail:

From: "Ralf S. Engelschall" <rse@engelschall.com>
To: apbugs@apache.org
Cc:  Subject: Re: mod_rewrite/3874: RewriteLock doesn't work for virtual hosts and silently fails
Date: Wed, 10 Mar 1999 13:54:57 +0100

 In article <19990210212537.10345.qmail@hyperreal.org> you wrote:
 
 >[...]
 > The lock file is opened during the init_child() phase and the file pointer is
 > saved in that server_rec, but that config info isn't propagated to the virtual 
 > host config.  Since the file pointer isn't available, even though locking is 
 > turned on, no locking is done and no warning is given and things break.
 >>How-To-Repeat:
 > Add a logging line to rewritelock_alloc() like
 > 
 >     if (conf->rewritelockfp != -1) {
 >         fd_lock(r, conf->rewritelockfp);
 >     } else if (conf->rewritelockfile) {
 >       ap_log_rerror(APLOG_MARK, APLOG_NOERRNO|APLOG_ALERT, r,
 >                    "mod_rewrite: Don't have lockfile descriptor, can't lock");
 >     }
 > 
 > then use RewriteLock and RewriteMap inside and outside of a virtual host
 > and you'll see that the lockfile fp isn't available through the virtual
 > host config, so no locking is done.
 >>Fix:
 > I moved the
 >         rewritelock_open(s, p);
 > call from the init_child() function to the server for loop in 
 > init_module() where the rewritelog open is as well, and that seems
 > to have fixed it.
 
 You're right that there might be a problem caused by the fact that the
 filedescriptor isn't merged into virtual host.  But your solution (moving the
 rewritelock_open call to the init_module function) is incorrect, because this
 doesn't work on platforms where flock() is used.  Because under flock() based
 locking the file _has_ to be opened by the child. So the only solution seems
 to be to interate in init_child() over the virtual hosts.  I'll look at
 this...
                                        Ralf S. Engelschall
                                        rse@engelschall.com
                                        www.engelschall.com
State-Changed-From-To: open-analyzed
State-Changed-By: dgaudet
State-Changed-When: Tue Apr 20 16:52:34 PDT 1999
State-Changed-Why:
Ralf, how's it going?
State-Changed-From-To: analyzed-closed
State-Changed-By: dgaudet
State-Changed-When: Tue Aug  3 11:17:29 PDT 1999
State-Changed-Why:
A patch has been applied to 1.3.8-dev which should fix this...
1.3.8 should be out shortly.

Dean
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