Setting permissions on serial port

[Jon Stanley]

On 12/20/07, Tom Horsley <tom.horsley at att.net> wrote:

> Yea, I finally did that myself, much simpler that wading through
> the maze of udev stuff :-).

udev is actually fairly easy.  I just took RH436 (Red Hat Clustering
and Storage Management) where there's a unit on udev.  To find out all
of the attirbutes that you can use to describe a device, the following
command is useful:

udevinfo -ap `udevinfo -q path -n /dev/sda`

replacing /dev/sda with the serial port that you are interested in.  I
would probably use for the harddrive above:

KERNEL=="sd[a-z]$", ATTRS{model}=="ST3808110AS     ",
OWNER=="someone", GROUP=="something", SYMLINK+="whatever"

For that specific model of drive in my machine (for some reason there
is no ATA serial number provided by libata :( ), that will set the
owner to someone, group to something, and add a symlink /dev/whatever
to it.  For the USB serial port, I would probably add BUS=="usb" and
the serial number of the serial port.

Put this in /etc/udev/rules.d/75-custom.rules for example.