[Dragora-bug] pmount and udev

[kelsoo]

Hi Dragorians

I have been trying to find a easy and light way to mount external drives 
via rox I found these links.

refs:

https://blog.debiania.in.ua/posts/2013-03-24-automounting-with-udev-and-pmount.html

http://www.monperrus.net/martin/automounting+usb+flash+drives+on+linux+with+udev+and+pmount

http://hakerdefo.blogspot.co.uk/2014/06/how-to-automount-usb-drives-and-memory_3.html

Then used a bash script with launcher icon in rox to run these scripts 
to mount and unmount external usbs.

pmount-usb

#!/bin/bash
pmount /dev/sdc1
pmount /dev/sdd1
pmount /dev/sde1
pmount /dev/sdf1
pmount /dev/sdg1
pmount /dev/sdh1
pmount /dev/sdi1
pmount /dev/sdj1
rox /media/

I have two internal  harddrives sda1, sdb1.

pumount-usb

#!/bin/bash
pumount /dev/sdc1
pumount /dev/sdd1
pumount /dev/sde1
pumount /dev/sdf1
pumount /dev/sdg1
pumount /dev/sdh1
pumount /dev/sdi1
pumount /dev/sdj1

It works fine for me and allows a normal user to mount and unmount 
external drives but has a few things that need sorted. Some of which 
maybe found here?

http://hakerdefo.blogspot.co.uk/2014/06/how-to-automount-usb-drives-and-memory_3.html

Until then the issues are.

1. It mounts all external drive so if you want to plug in another you 
need to unmount all and remount again. If you dont it will remount the 
same drive at another mount point.
2. It does not use UUID so or labels that reflect the real name of the 
drive. Maybe this is because it only uses udev and pmount?


I contacted Minoru at Selks request and asked him to drop into the irc 
channel, he did.

Here is a shortend summary:


 selk: Minoru, we are trying to avoid udisks and company looking for a 
sane and lightweight alternative (or unbloated)
if we can do this with eudev and mount(1), it would be great but we want 
to know your experience and what are you using in these days.

Minoru: well, I definitely hope you succeed, cause it's a damn shame I 
can't have A-grade automounting on my lightweight desktop.
kelsoo: selk said: selk: 1. If we can do the same of pmount(1) with 
mount(1)
kelsoo: selk: 2. How the devices are discovered to be handled for our 
(p)mount rules
Minoru: okay, so re 1 (using mount instead of pmount). That's definitely 
possible, but will require more work on your part. pmount automates away 
the process of choosing options for mounting, creating the mountpoint 
and running mount(1)
so if you don't want pmount as dependency, you can write a script that 
will run blkid or something to figure out what FS does the device 
contain, then run mount(1) with appropriate options
as for the device discovery (question 2), I delegated that to udev. My 
blog post describes rules I wrote for the demon, so that when I plug 
something in, udev discovers it and runs my command (pmount)
and as far as I recall, udev seem to be the cleanest and most logical 
way to approach that - this demon is responsible for the PnP, after all 
but the rules syntax is, er, rather unwieldy, so maybe you only want a 
generic rule that will react to *any* device that is plugged in, and run 
your program. And your program will be the one responsible to figure out 
if it's a disk, and what to do about it

selk: I understand, a wrapper using blkid, mount (and probably 
mountpoint)
selk: interesting
selk: yes, generic rules would be fine
selk: very nice Minoru

Minoru: oh, by the way, there's one thing that my rules probably won't 
cover, and that's cryptocontainers. I'm not sure, you have to check udev 
documentation, but I think my rules won't react. The gist is as follows: 
when you plug in a USB stick with a cryptocontainer on it (I'll use LUKS 
as example), you'll see just one device. file(1) will tell you it's 
LUKS, and blkid will as well. You then have to ask the user for 
password, then run cryptsetup(8). ...After that, a device will appear 
under /dev/mapper (it will be named however you want it to be) - that 
one you can mount, finally, with the workflow described above



according to Minoru, we need:

1. Eudev
2. Mount or Pmount (mount(1) ideally)
3. Rules for udev
4. A wrapper script to handle the devices
5. The crypto support.

Kelsoo