File permissions on tty's created by the dgrp daemon

Realport
1

I am wondering if it is possible to have the dgrp daemons
create the file permissions on the tty’s it is creating
to be ‘777’. I am running Red Hat AS 2.1 dgrp 1.7-1.
The ttys are being created as;

crw------- 1 root root 254, 2 May 28 15:06 tty002

The problem is that I have some of the serial ports connected
to devices that need to be accessed by general users. I am
reading the man page on dgrp_cfg_node and it appears that
you have the ability via the -m , -o and
-g . However, the documentation is not very clear
on this. So, I used the dgrp_gui to make the assumed
changes and what happens is that it issues the command, I
go back to see if the changes ‘took’ and everything is back
to ‘default’. I do a ls -al /det/tty002 and permissions are
still the same. Am I looking in the right direction here ?
Does anyone know how to go about this ?

2

These settings will only be applied when creating the devices and will not change existing devices. This is by design since, the devices are all recreated after a reboot with the original daemon settings.

Try removing the entry and re-adding with the new device permission settings.

3

So are you saying that linux is creating the tty’s and not
the dgrp daemons ? If this is true, I guess I’ve misunderstood what the dgrp daemons are doing. Here are some pieces to the puzzle.

backing store config file;

ID IP PortCount SpeedString IPPort Mode Owner Group Encrypt EncryptPort

0 192.168.101.60 16 auto default 777 502 502 never default

Here is the inittab for said tty’s (some printers and
some terminal logins);

D0A:2345:respawn:/sbin/agetty tty000 9600 vt100 -L
D0C:2345:once:< /dev/tty002 > /dev/null &
D0D:2345:once:ditty-rp 9600 /dev/tty002
D0E:2345:respawn:/sbin/agetty tty003 9600 vt100 -L
D0F:2345:respawn:/sbin/agetty tty004 9600 vt100 -L
D0G:2345:respawn:/sbin/agetty tty005 9600 vt100 -L
D0H:2345:respawn:/sbin/agetty tty006 9600 vt100 -L
D0I:2345:respawn:/sbin/agetty tty007 9600 vt100 -L
D0J:2345:respawn:/sbin/agetty tty008 9600 vt100 -L
D0K:2345:respawn:/sbin/agetty tty009 9600 vt100 -L
D0L:2345:respawn:/sbin/agetty tty012 9600 vt100 -L
D0M:2345:once:< /dev/tty013 > /dev/null &
D0N:2345:once:ditty-rp 9600 /dev/tty013
D0O:2345:respawn:/sbin/agetty tty014 9600 vt100 -L
D0P:2345:respawn:/sbin/agetty tty015 9600 vt100 -L

This is something comming up in the /var/log/messages;

May 24 12:33:30 testuv modprobe: modprobe: Can’t locate module char-major-254

It a coincidence that 254 is major for the tty’s in question. Finally, this is a lising of the ‘/dev’ files. I really dont understand why the tty010 and tty011 have the permissions they way they do.

crw------- 1 root root 254, 0 May 28 16:49 tty000
crw------- 1 root root 254, 1 May 28 16:48 tty001
crw------- 1 root root 254, 2 May 28 16:48 tty002
crw------- 1 root root 254, 3 May 28 16:49 tty003
crw------- 1 root root 254, 4 May 28 16:49 tty004
crw------- 1 root root 254, 5 May 28 16:49 tty005
crw------- 1 root root 254, 6 May 28 16:49 tty006
crw------- 1 root root 254, 7 May 28 16:49 tty007
crw------- 1 root root 254, 8 May 28 16:49 tty008
crw------- 1 root root 254, 9 May 28 16:49 tty009
crw-rw-rw- 1 root root 254, 10 May 28 16:48 tty010
crw–w---- 1 root root 254, 11 May 28 16:48 tty011
crw------- 1 root root 254, 12 May 28 16:49 tty012
crw------- 1 root root 254, 13 May 28 16:48 tty013
crw------- 1 root root 254, 14 May 28 16:49 tty014
crw------- 1 root root 254, 15 May 28 16:49 tty015

Does any of this make sense ? If so care to elaborate a little more so that I can understand it as well.
Thanks

4

The dgrp daemons create the devices on every boot with the settings specified in the backing store file. For open permission settings on the devices a 4 digit value needs to be added. For example: 0777

The different permissions shown on the two ports you pointed out, appear to have had the permissions changed after the initial boot/device creation (perhaps an application?).

The /var/log/messages error indicates that the dgrp daemon is unable to communicate with the unit. This error is commonly seen when there is a getty running on a port that is not accessible.

5

So, I changed the permissions as suggested. The backing store file is now;

0 192.168.101.60 16 auto default 0777 default default never default
1 192.168.101.61 16 auto default 0777 default default never default
2 192.168.101.62 16 auto default 0777 default default never default
3 192.168.101.63 16 auto default 0777 default default never default
4 192.168.101.64 16 auto default 0777 default default never default
5 192.168.101.65 16 auto default 0777 default default never default
6 192.168.101.66 16 auto default 0777 default default never default
7 192.168.101.67 16 auto default 0777 default default never default
8 192.168.101.68 16 auto default 0777 default default never default
9 192.168.101.69 16 auto default 0777 default default never default
A 192.168.101.70 16 auto default 0777 default default never default

I changed the 192.168.101.60 to be owned by default instead of group 502 as well. I wasnt sure about this to begin with. The /dev/ttys are still comming up with the same permissions as before. There isnt an application running that is using /dev/tty010, dev/tty011. So, I dont understand how these permissions are being set they way they are.

The ‘messages’ entry still appears, which is;
Jun 1 11:38:05 testuv modprobe: modprobe: Can’t locate module char-major-254
Jun 1 11:38:05 testuv modprobe: modprobe: Can’t locate module char-major-254
Jun 1 11:38:05 testuv modprobe: modprobe: Can’t locate module char-major-254
Jun 1 11:38:05 testuv modprobe: modprobe: Can’t locate module char-major-254
Jun 1 11:38:05 testuv modprobe: modprobe: Can’t locate module char-major-254
Jun 1 11:38:05 testuv modprobe: modprobe: Can’t locate module char-major-254
Jun 1 11:38:05 testuv modprobe: modprobe: Can’t locate module char-major-254
Jun 1 11:38:15 testuv modprobe: modprobe: Can’t locate module char-major-254
Jun 1 11:38:15 testuv modprobe: modprobe: Can’t locate module char-major-254
Jun 1 11:38:16 testuv modprobe: modprobe: Can’t locate module char-major-254
Jun 1 11:38:17 testuv modprobe: modprobe: Can’t locate module char-major-254

It appears that it is listed one time for each tty it is trying to spawn off a login on in the /etc/inittab.

You mentioned that this is usually caused by a getty running on a port that is not accessible. Im not sure I know what to do about this ?

Does all of this appear buggy or am I doing something wrong ?

6

Seems as though the driver is failing and not the daemon:

Jun 1 11:38:17 testuv modprobe: modprobe: Can’t locate module char-major-254

This occurs when the system doesn’t currently have a driver for that major loaded,so modprobe is called to try to find a driver to autoload that will claim major 254.

  1. If you run “/sbin/lsmod”, is dgrp listed?
  2. Run /etc/init.d/dgrp stop
  3. Run /sbin/rmmod dgrp (assume 1. came back with the driver loaded)
  4. Run /etc/init.d/dgrp start
  5. Run “/sbin/lsmod”, is dgrp listed now?

If on 5) the driver is not listed, there is the real problem you need to resolve. A typescript of the driver compilation/installation may give some clues.

The “mknod/chown” stuff is not run until the driver is loaded into the kernel correctly.

7

during the lsmod, dgrp is listed;
[root@testuv init.d]# /sbin/lsmod
Module Size Used by Not tainted
dgrp 80532 133

the /etc/rc.d/init.d/dgrp_daemon stop is successful

Now the next command /sbin/rmmod dgrp will not execute, because of error;

[root@testuv init.d]# /sbin/rmmod dgrp
dgrp: Device or resource busy

I guess this is because of all the gettys still hanging around ??

When you stop the daemon from running is it supposed to stop all gettys ?

Anyway, this is as far as I got. From what I recall I did not encounter any errors during the driver install.

Any workarounds for step #3 ?

8

At this point, I recommend contacting Digi Tech. Support.