From: [EMAIL PROTECTED]
Subject: httpd / mod_dav locking troubles (DavLockDB is chrooted
relative)
Date: February 28, 2006 7:21:59 AM PST
To: [EMAIL PROTECTED]
I'm running OpenBSD 3.8 stable with mod_dav 1.0.3p0 installed from
ports (sparc64 architecture).
My goal is to get mod_dav working over https. While https is working
ok, and my DAV client (Mac OS X 10.4.5) can connect and authenticate,
any time the client attempts to create a file it will hang. Examining
the error_log shows the following message repeated many thousands of
time (before I killed httpd and waited for the Mac to timeout):
[Sun Feb 26 22:42:47 2006] [error] [client 10.0.254.2] Could not save
lock information. [500, #405]
[Sun Feb 26 22:42:47 2006] [error] [client 10.0.254.2] (22)Invalid
argument: No error. [500, #0]
I have not found anyone posting a solution to this issue. The best I
could find was one other person having the same issue, but didn't get
a response. The URL for the other post is:
http://mailman.lyra.org/pipermail/dav-dev/2005-November/006209.html
We're both running OpenBSD on sparc64 (though he was running 3.7).
I've tried running apache both chrooted (httpd_flags=-DSSL) and
unchrooted (http_flags=-u -DSSL). The change had no effect on this
issue. SSL and authentication have not been a problem. Here's the DAV
relevant portion of my httpd.conf:
Alias /dav/ /var/www/dav/files/
DavLockDB /dav/lockdb
Directory /var/www/dav/files/
Dav on
AuthType Digest
AuthName DAV
AuthDigestDomain /
AuthDigestFile /var/www/dav/dav_users
AuthGroupFile /var/www/dav/dav_groups
Options none
AllowOverride none
LimitExcept GET HEAD OPTIONS
require valid-user
/LimitExcept
Order allow,deny
Allow from All
/Directory
The owner and permissions on the /var/www/dav/ directory look fine:
drwxrwxr-x 3 www www 512 Feb 27 21:52 dav/
The lock database is created in /var/www/dav, but I noticed the files
have a zero size:
-rw-r- 1 www www0 Feb 27 21:52 lockdb.dir
-rw-r- 1 www www0 Feb 27 21:52 lockdb.pag
I haven't done anything special with my var partition (on a side
note, I spaced it install time but /var/www/ will wind up on its own
partition):
/dev/wd0g on /var type ffs (local, nodev, nosuid)
/var/log/messages doesn't have anything post relevant, just boot
stuff and a couple syslog restarts.
I re-worked my httpd.conf to only run a single httpd instance
(StartServers, MinSpare, and MaxSpare all set to 1), restarted httpd,
and ktraced the httpd child process. Here's the portion of the output
that deals with the lock db:
29913 httpdCALL open(0x42d887f0,0x202,0x1b0)
29913 httpdNAMI /dav/lockdb.pag
29913 httpdRET open 7
29913 httpdCALL flock(0x7,0x2)
29913 httpdRET flock 0
29913 httpdCALL open(0x42d887e0,0x202,0x1b0)
29913 httpdNAMI /dav/lockdb.dir
29913 httpdRET open 8
29913 httpdCALL fstat(0x8,0xfffbe0a0)
29913 httpdRET fstat 0
29913 httpdCALL gettimeofday(0xfffbe960,0)
29913 httpdRET gettimeofday 0
29913 httpdCALL stat(0x4f2df090,0xfffbe660)
29913 httpdNAMI /dav/files/._index copy.html
29913 httpdRET stat 0
29913 httpdCALL close(0x8)
29913 httpdRET close 0
29913 httpdCALL flock(0x7,0x8)
29913 httpdRET flock 0
29913 httpdCALL close(0x7)
29913 httpdRET close 0
The lockdb.pag file is opened successfully (file descriptor 7) and
flock reports the exclusive lock was obtained alright (the open and
flock man pages helped here). However, httpd still seems to be having
some sort of issue related to locking. I haven't touched systrace
since I did a fresh install of 3.8 (all I see in /etc/systrace are
usr_sbin_lpd and usr_sbin_named).
I did some digging in the mod_dav source and found that the Could
not save lock information is only issued in one place, and that is
if a call to sdbm_store (via a function pointer) is failing with
EINVAL (errno value 22 in the above error_log snippet). It's returned
from sdbm_store because either the database is NULL, or the key data
pointer is NULL or has a zero size. Searching for various
combinations of sdbm, DAV, sparc, and OpenBSD didn't find anything
that looked relevant. If someone has already seen / patched / worked
around this, I'd rather not waste time creating a debug build of
httpd / mod_dav (my only sparc box is on the slow side).
Any help or insights appreciated.
Nick
