Aliases Helper

Introduction

The aliases are used by the Mail Transfer Agents. They're used to:

• define "human-readable" email addresses,
• define mail list addresses,
• define "technical" aliases, email addresses for a range of programs or services.

Thus, several different configuration tools may generate aliases:

• linuxconf (for user aliases),
• BeroList, SYMPA (for the mail list addresses),
• the administrator (for the various program aliases),
• etc.

These tools are run with different access rights, and under different user accounts, which poses some difficulties to set the access rights of the aliases file, and which implies the use of the u+s or g+s flags (with their associated security risks).

On the other hand, aliases are gathered into and used from several different databases, used by different parts of the system (sendmail, postfix, and for example, netinfo on NeXTSTEP).

To manage the flow of alias definitions between these programs, the aliases_helper daemon has been developed.

aliases_helper Description

Each configuration tool writes its own aliases file. aliases_helper is a daemon whose job is to periodically check these various aliases files, and to merge them (optionnaly making as many copies as needed). Then, it runs some configurable commands to rebuid the aliases databases used by the various other programs.

Sample of configuration file /etc/aliases_helper.conf:

#
# aliases_helper configuration file.
#

#
# Note that for now, a line may contain either a comment or a configuration
# statement, but not both.
#
# This configuration file is read once when aliases_helper is started,
# and then once every time the aliases_helper process receives a HUP signal.
#


# 
# Period is expressed in seconds. It is the period for checking if any
# of the input aliases files has changed.
#
period 60


#
# One or more input paths may be specified.
#

input /etc/aliases.txt
input /etc/aliases.linuxconf
input /var/lists/aliases


#
# One or more output paths may be specified. All are copies of the same
# output file.
#

output /etc/aliases
output /etc/postfix/aliases


#
# One or more commands to be executed once the output aliases files are
# written.
#

execute /usr/bin/newaliases
execute /usr/sbin/postalias  /etc/postfix/aliases
#execute /etc/niload aliases . < /etc/aliases
execute /bin/mail -s 'List Aliases' informat < /var/lists/aliases


#
# END.
#

The aliases_helper program is written in Objective-C, and uses the OpenStep foundation object library, FoundationKit. It has been developed and tested with the GNUstep implementation, but it should integrate and work as well with either:

• libFoundation,
• GNUstep,
• OPENSTEP (4.2),
• MacOSX.

The classes used by aliases_helper are: NSArray, NSAutoreleasePool, NSCharacterSet, NSData, NSDate, NSEnumerator, NSException, NSFileHandle, NSFileManager, NSMutableArray, NSMutableData, NSMutableDictionary, NSMutableString, and NSString.

Downloading aliases_helper

Aliases_helper is released under the GNU Public License (GPL). Commercial licenses are available for inclusion in commercial non-free software (Contact mailto:pjb@hubble.informatimago.com ).

You may get the source of aliases_helper from:

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