What is Halevt?
===============

Halevt (HAL events manager) is a daemon that executes arbitrary commands 
when a device with certain properties is added to the system and when 
device properties change. Halevt uses HAL to monitor the state of your 
system's hardware. Example config files show how to handle the mounting 
of media as they are inserted/attached to the system.

Halevt comes with halevt-mount a program able to use HAL to mount, umount 
devices and keep a list of devices handled by halevt-mount.


Who wrote it?
=============

The initialization of hal and dbus is based on gnome-volume-manager, 
by Robert M. Love. The remaining is by Patrice Dumas 
<pertusus at free dot fr>.

The design is largely based on Ivman which was written by 
Ikke <eikke at users dot sourceforge dot org>, and
maintained by Rohan McGovern afterwards.

halevt-mount is loosely based on gnome-mount, but in the end the
dbus API and hal specification of DBus interface were used and no
code was borrowed.


Homepage
========

http://www.nongnu.org/halevt/

You can reach the current maintainer at <pertusus at free dot fr>.
The preferred channel for communication is the mailing list at
http://lists.nongnu.org/mailman/listinfo/halevt-dev.


Install
=======

libxml2, D-Bus, glib and D-Bus glib and HAL are required.
A less known library is also needed, boolstuff which may be found at
http://perso.b2b2c.ca/sarrazip/dev/boolstuff.html
boolstuff has to be version >= 0.1.12.

Halevt uses the autotools, so may be installed simply with

./configure
make
make install

When run as root (system-wide) the default is to drop privileges 
and run as the halevt user. A make target allows to create this 
user and set the permissions to the directories that it should own:

   make perms

For automounting to work well, it is advisable to have either 
gnome-mount, pmount or halevt-mount (provided with halevt) installed 
for user mount, and pmount installed for system-wide mounts. 

The non standard glibc daemon function is used, it could be missing on
some platform.

To regenerate the documentation after a modification, makeinfo and 
man2html are needed.

Development packages on different distributions:

On debian: libxml2-dev dbus-glib-1-dev libhal-dev boolstuff-dev

On Fedora: dbus-glib-devel hal-devel libxml2-devel boolstuff-devel
           gettext pkgconfig


Starting from CVS
=================

You need autoconf, automake, autoreconf, gettext and autopoint. You can 
use the script bootstrap.sh shipped in CVS, like

./bootstrap.sh


Configuration
=============

If a config file is given on the command line no other file is used.

If no config file has been specified config files are searched first 
in the user home directory in .halevt/, then in the system configuration 
directory which is typically along /etc/halevt, and last in the vendor 
directory which is typically along /usr/share/halevt/.

All the files ending with .xml found in these directories are considered
to be configuration files. If a file with the same name has already been 
found in a previous directory, it is ignored. This allows to override
vendor configuration files by system configuration files, and system 
configuration files by user files. The configuration files should be xml
files, for the format see the examples shiped with halevt (some examples
are in the examples/ directory) and the documentation.

Some examples are available in the examples/ directory. The example in 
automatic_sync_mount.xml leads to removable devices being automounted
with the sync option, in order not to lose data. However, be warned 
that in case of media with limited number of write cycles (e.g. some 
flash drives) "sync" may cause life-cycle shortening, and the 
performance is reduced a lot compared with the default "async" option.
The halevt-mount program is used to mount or unmount through hal and keep
a list of mounted and inserted devices by querying hal.

The umount_from_tray-gtkdialog.xml example is similar and additionally shows 
how a tray icon can be added upon insertion of a removable media, that 
can be used to umount the media. Since there is an icon to do the umounting,
devices are not mounted sync. The script halevt_umount_from_tray-gtkdialog.sh, 
installed in the default case, installs the icon in the tray and prepares
the pop-up window that allows to umount the device. This example requires
alltray and gtkdialog. A similar example umount_from_tray-xmessage.xml
uses the script halevt_umount_from_tray-xmessage.sh and xmessage.

Another example is given, in the file automatic_mount_with_hvmount.xml 
which uses the script hvmount for automounting; this script also allows 
to keep a list of mounted and inserted devices. gnome-mount, pmount(-hal) 
or mount are used to perform the actual mount. 


Usage
=====

The commands accept the -h switch to show their help.

A typical use would be to add, in login scripts

   halevt -p ~/.halevt/halevt.pid

And in log out scripts

   kill `cat ~/.halevt/halevt.pid`

If you want halevt to run system-wide, you could use the halevt-initscript.
It has been tested on a fedora. It is likely that strange things will happen 
if you mix up running halevt system-wide and as users. There may be some
permission issues when running system-wide. Indeed, the halevt user should
be able to access devices, and users should be granted the right to access
to devices handled by halevt.

You may have to add something along the following to the PolicyKit
config file, which could be in /etc/PolicyKit/PolicyKit.conf:

<!DOCTYPE pkconfig PUBLIC "-//freedesktop//DTD PolicyKit Configuration 1.0//EN" "http://hal.freedesktop.org/releases/PolicyKit/1.0/config.dtd">

<!-- See the manual page PolicyKit.conf(5) for file format -->

<config version="0.1">
<match user="halevt">
  <return result="yes"/>
</match>
</config>



If you use halevt-mount
-----------------------

Automatically mounted devices may be unmounted by calling

   halevt-umount <mount_point>

All mounted devices may be unmounted by calling

   halevt-umount -a

You can update the information available to halevt-mount (usefull
if halevt is not running, for example) by calling

   halevt-mount -s

You can remove all the devices information (for example in a 
login script) by calling

   halevt-mount -c -a

To unmount all the devices, you could add

   halevt-umount -a

to your logout script.


If you use hvmount
------------------

Automatically mounted devices may be umounted by calling

   hvumount <mount_point>

All mounted devices may be umounted by calling

   hvumount -a

If you want to use the automounting facilities, you could also add, in your
startup scripts:

   hvmount clean

This cleans possible stale devices registered by hvmount. This can happen,
for example, if devices are removed after halevt is stopped.

And in log out scripts, to umount all the devices:

   hvumount -a


Notes
-----

hvmount and halevt-mount use the same file to store their information, 
the same lock file and the same format, so they should cohabitate well,
but it isn't widely tested, and is a bit silly.

If you really want to run halevt as root you'll have to specify:
  -u root -g root

When using pmount/pumount you have to unmount all your devices before 
removing the removable media, since pumount cannot operate without the
device file.

When devices have been mounted through HAL and the device is removed 
without unmounting, HAL should unmount the file systems automatically.