[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]

Re: /dev/ttyUSB?? permissions



On Tue, Jun 01, 2004 at 07:35:52PM -0500, dsavage peaknet net wrote:
> 
>      # chmod a+rw /dev/ttyUSB??
> 
> did jpilot's sync function come back to life. Can anyone explain to me why
> the original permissions on USB devices are 660 and not 666? Is this
> something that should be Bugzilla'd?


The reason is that the possible uses for a tty device (including USB
ttys) have conflicting permissions and configuration sets.  

There are a number of devices that should change ownership and
permissions when a user logs in at the console.  These changes are
configurable, inspect the file:

    /etc/security/console.perms 

and the man page for it:

    $ man console.perms

The obvious issue for a multiuser internet connected system is that
wide open permissions permit any user to futz with the device.  While
you might not have an issue with your brother and other members of the
family other systems have less friendly users.

Then there is the potential issue of data corruption on the palm
should two programs interact with the device at the same time.

Sitting here I suspect that jpilot should do a stat() and fuser
equivalent on the device and see what the permissions and ownership
are.  If they are wrong it should then present an informative screen
(pointer to documentation) that makes it possible for a user to
configure things correctly.  Reread the good and bad hints you have
been given here and file a bugzilla rfe (request for enhancement)
against jpilot that captures the helpful hints in a way that the
maintainer has a chance of simplifying the program's user
interactions.

We all have had a family member grab a phone and start dialing without
listening to see if the line was in use.  If it is just voice it is
simply rude and hard on the ears.  If it is a modem connection the
connection is dropped and perhaps data lost (call waiting).  Now was
that on line house payment made?



-- 
	T o m  M i t c h e l l 
	/dev/null the ultimate in secure storage.



[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Thread Index] [Date Index] [Author Index]