Data flow in chain kernel->udev->hal

[Kay Sievers]

On 10/7/07, Luckichov Denis <psea at yandex.ru> wrote:
> Hello all. I'm trying to understand how hal knows about device names that udev makes. Let's take an example. I have a flash disk. When i plug my flask disk, kernel send a message through socket to udev. In that message we have an ACTION and a path in sysfs for that device  (my flash). udev takes information from sysfs, apply ruses, and we have lets say /dev/myflash. After udev send a message through socket to hal (RUN="socket:/org/freedesktop/hal/udev_event). In that message we have an ACTION and a path in sysfs, and we don't have device filename (/dev/myflash). And here a question: how hal knows about my device filename? In sysfs we have only a kernel name (for example /dev/sda1) and don't have /dev/myflash.

DEVNAME is passed in the environment.
Run "udevmonitor --env" and plug in your drive, and watch it.

Kay