I am a big fan of qmail. I honestly think it's the best MTA around, even if it has a few issues. Well, what doesn't?
Since I manage a few small and large installations, I think it's only fair that I document what those issues seem to me, and what solutions I've found.
One thing about qmail is that its queue, for sake of efficiency, is not as easy to manipulate as, for example, sendmail's.
So, I've found some tools, and written some more, to help manage, control and manipulate qmail's message queue.
But first:
When you use one of the tools described below, or look in qmail's logs, you will find things like mentions of "msg 457" being queued. What is that?
Well, the number is just an identifier, and you will find files called 457 in qmail's queue directories.
Qmail's queue consists of several directories. Some of them, which can be expected to hold many hundreds or thousands of files are split into numbered subdirectories. That is because in Unix, normally finding a file in a directory becomes slow if that directory contains many files.
A message going through qmail will have related files in several places in that directory structure.
The following is from qmail's INTERNALS file, some of these files will exist, some not:
The number of the internediate directory (20 in this example) is the remainder of dividing the message number by 23... at least by default ;-)
The numbers used to identify the messages are not arbirary and you should never change them unless you really know what you are doing. If you mess that up, maybe queue-rename (see below) can fix it.
If you remove a file, make sure you remove all the related ones, too, or qmail will whine.
If you gonna be messin' with qmail's queue, make sure you shut qmail-send down first. Bad things happen if you don't.
[root@correo root]# qmail-qread
16 Sep 2003 21:13:33 GMT #145337 2218 <joe@home.com>
remote shmoe@work.net
[root@correo root]# qmail-qstat
messages in queue: 1025
messages in queue but not yet preprocessed: 2
Important notes: This will simply print a list of the messages it finds matching your criteria. Since regular expressions are easy to get wrong, you should be careful about what you do with that list, because it could not be what you wanted....
In any case, it is easy to modify qmail-cleaner to output a qmHandle command line that would, for example, remove those messages from the queue. Such potentially destructive version is left as an exercise to the reader, though.
if you have any suggestions or problems with the script, please post a comment.
#!/usr/bin/env python
import sys,os,re
#Option handling nice and easy through Optik, http://optik.sf.net
from optik import OptionParser
parser = OptionParser()
parser.add_option ("-d", "--queue-dir",action="store", type="string", dest="queuedir",
help="The qmail queue directory, default=/var/qmail/queue",
default="/var/qmail/queue")
parser.add_option ("-s", "--sender",action="store", type="string", dest="sender",
help="Find messages with a From: header matching this regexp",
default=None)
parser.add_option ("-t", "--to",action="store", type="string", dest="to",
help="Find messages with a To: header matching this regexp",
default=None)
parser.add_option ("--header",action="store", type="string", dest="header",
help="Find messages with any header matching this regexp",
default=None)
parser.add_option("-v", action="store_true", dest="verbose", help="Verbose",default=0)
parser.add_option("-q", action="store_false", dest="verbose", help="Quiet")
(options,args) = parser.parse_args (sys.argv)
#This is where the messages are
msgdir=options.queuedir+"/mess"
#Array of matching messages
matches=[]
#Create the regexp to be matched
regex=""
if options.header: #User gave us a full regexp
regex=options.header
elif options.sender: #User asks for a From: header
regex="^From: "+options.sender
elif options.to: #User asks for a To: header
regex="^To: "+options.to
exp=re.compile(regex)
if options.verbose:
print "Searching messages with headers matching: %s\n"%regex
#Function that checks if a message matches our criteria
def check(message):
global exp,matches
for line in open(message):
#Only check the headers, so stop on blank line
if len(line)==1:
return
#Check for match
if exp.search(line,1):
matches.append(message.split("/")[-1])
return
#Get list of split directories (usually they are 23, but why bet)
try:
dirs=os.listdir(msgdir)
except:
sys.stdout.write("Error listing queue directories")
sys.exit(1)
#Walk the tree and examine each file
for dir in dirs:
files=os.listdir(msgdir+"/"+dir)
for file in files:
check (msgdir+"/"+dir+"/"+file)
#report files matching our criterion
for match in matches:
print match
Sample run of qmail-cleaner.py:
[root@correo p]# ./qmail-cleaner.py --header=ralsina -v
Searching messages with headers matching: ralsina
145443
145307
146746
144469