[TAG] lpr works for user not root in Basiclinux 2.1

Sindi Keesan keesan at grex.cyberspace.org
Sat Mar 24 23:36:44 MSK 2007


I have been experiencing spontaneous permission changes on devices after 
using them as user:

/dev/ttyS1  (needed to dial with pppd and hardware modem)
/dev/ttyp0  (needed by rxvt)

And on another computer
/dev/ttyLT0 (lucent modem)

The lucent modem ownership was root tty (I had made it match all the other 
ttys that came with Basiclinux 2.1).

Various online suggestions from people with similar problems were:

1) something happened when they used samba (I don't have that);
2)  they shut down with the application (Eterm) running - I cannot shut 
down with rxvt running, if I hit Ctrl-Alt-Del it just exits X.
3)  something to do with kernel 2.2.19 and the program expected 2.4.31
(I have 2.4.31 kernel)
4)  someone fiddled with file permissions and ownerships and fixed it.

So I looked at Basiclinux 3 and the ownership is root root, not root tty.
I don't recall having similar problems there.

I had ownerships root tty for /dev/ttyLT0 (on this computer) and root root 
for /dev/ttyp0) (on this computer) and the former kept resetting when I 
rebooted and the latter did not.  I might have all tty* root tty on the 
other computer.  I have been messing around too much.  I KNOW some things 
came set root tty.

I changed group of ttyLT0 to users and the problem is cured.

Should I be using root root or root users for my devices that I want to be 
accessible to user?  ttyS1 or ttyLT0, and ttyp0-4 (four rxvts), and 
/dev/dsp0 (sound) and /dev/lp0 (printer).  These are currently all root 
root except for the serial/modem devices.

Setting things 'group tty' appears to reset permissions so only root can 
write to the device.






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