How can my perl script react to arbitrary devices using UDev and not HAL?

Question

I'd like to use a simple Perl script to make some configurations every time I connect e.g. my bluetooth headset. I tried using Net::DBus, but my OS/DE (Fedora 17, GNOME3) doesn't use HAL anymore.

I really don't want to install HAL just for this, so what do I do? My ideas so far:

• (Preferred): Use DBus; simply listen to UDev events instead of org.freedesktop.Hal. Problem: I cannot find the corresponding service, org.freedesktop.UDisks only seems to monitor disks (duh). Does UDev even send DBus messages for other devices and if not, can I configure it to do so?
• Use an UDev rule to trigger another script. I like to have my scripts in one place for easy transition to new OS installs, so I'd rather avoid that.
• Am I better off just using Python to listen directly to UDev?
• Or can I use Perl to do just that? A CPAN search for "udev" didn't yield anything helpful.

Or I may be completely off and UDev isn't even what I need. Neither the docs nor Google were really helpful regarding that matter. A workaround would be if anyone knows how to get GNOME3 to switch audio output to a newly connected bluetooth headset per default, but I'd like to learn scripting stuff like that anyway.

Thanks in advance for any pointers!
A.

PS: By the way, Google&Co. claim that UDev gets the devices and sends a message to HAL, which in turn notifies DBus. That is most definitely not the case since HAL isn't even in the Fedora Repos aymore.

Answer 1

You can use Udev::FFI (cpanm Udev::FFI)

For example:

use Udev::FFI;

my $udev = Udev::FFI->new() or
    die "Can't create udev context.";
my $monitor = $udev->new_monitor() or
    die "Can't create udev monitor.";
$monitor->filter_by_subsystem_devtype('usb', 'usb_device');
$monitor->start() or die "Can't start monitor.";

for(;;) {
    if(defined(my $device = $monitor->poll())) {
        my $action = $device->get_action();
        if($action eq 'add') {
            #work with $device
...