Received: (qmail 75501 invoked by uid 501); 13 Jun 2000 00:48:34 -0000
Message-Id: <20000613004834.75500.qmail@locus.apache.org>
Date: 13 Jun 2000 00:48:34 -0000
From: David Saunders <drs8h@virginia.edu>
Reply-To: drs8h@virginia.edu
To: submit@bugz.apache.org
Subject: change needed to run off Linux ext2 read-only or WORM filesystem
X-Send-Pr-Version: 3.110

>Number:         6179
>Category:       os-linux
>Synopsis:       change needed to run off Linux ext2 read-only or WORM filesystem
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    apache
>State:          open
>Class:          change-request
>Submitter-Id:   apache
>Arrival-Date:   Mon Jun 12 17:50:00 PDT 2000
>Closed-Date:
>Last-Modified:
>Originator:     drs8h@virginia.edu
>Release:        1.3.12
>Organization:
apache
>Environment:
Slackware 7.0 CD
Linux 2.2.13 #3 i686 unknown
gcc version egcs-2.91.66 19990314/Linux (egcs-1.1.2)
>Description:
The Linux ext2 filesystem utility "chattr" enables Linux on a normal
hard disk to mimic a CDROM or a WORM drive.  "chattr -R =i *" sets
everything below the current directory to be "immutable", and 
"chattr -R =Sa" sets everything to append-only.  A Linux virtual
worm drive will consist of a mix of files in the filesystem being 
either immutable or append-only.  (The "S" is "Sa" means that 
the file is always synched, ie, new contents are written out immediately.)

Apache's serialized accept lock file has problems in this environment.
As coded, src/main/httpd_main.c appends the PID to the lock file name,
and, later, attempts to create this file name prior to the actual locking
requests by the child processes.

This patch 1) removes the PID append operation to the name, and 2) changes
the open on the file to not have O_CREAT and O_EXCL, and to have O_APPEND
(and the original O_WRONLY).

Prior to starting the server, the installer must "touch <acceptfile>" and
"chattr =Sa <acceptfile>".
>How-To-Repeat:
You should be able to set the LockFile name in conf/httpd.conf, apply the
patch, "touch" the lock file you specify, and chattr it to "=Sa".
(Other apache files can also be append-only, or deriected to /dev/null.)

Then apply the patch below, build apache and start the server.
>Fix:
Here's the patch.  In the long-run, I think having a conf directive would
be better.  Also, a conf directive to enable SINGLE_LISTEN_UNSERIALIZED_ACCEPT
might be useful for true CDROM implementations of Apache.

--- http_main-old.c     Tue Jun 13 09:11:43 2000
+++ http_main.c Tue Jun 13 09:13:46 2000
@@ -494,8 +494,8 @@
 static void expand_lock_fname(pool *p)
 {
     /* XXXX possibly bogus cast */
-    ap_lock_fname = ap_psprintf(p, "%s.%lu",
-       ap_server_root_relative(p, ap_lock_fname), (unsigned long)getpid());
+/*    ap_lock_fname = ap_psprintf(p, "%s.%lu",
+       ap_server_root_relative(p, ap_lock_fname), (unsigned long)getpid()); */
 }
 #endif
 
@@ -804,7 +804,7 @@
     unlock_it.l_pid = 0;               /* pid not actually interesting */
 
     expand_lock_fname(p);
-    lock_fd = ap_popenf(p, ap_lock_fname, O_CREAT | O_WRONLY | O_EXCL, 0644);
+    lock_fd = ap_popenf(p, ap_lock_fname, O_WRONLY | O_APPEND, 0644);
     if (lock_fd == -1) {
        perror("open");
        fprintf(stderr, "Cannot open lock file: %s\n", ap_lock_fname);

 
>Release-Note:
>Audit-Trail:
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