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losing serial port permissions

 
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# 1  
Old 07-14-2005
losing serial port permissions
I have a site running SCO 5 that after rebooting loses full permissions on the serial port tty2a. This port is a link between hotel and restaurant. Without full permissions there is no communication. Change tty2a back to full permissions logged in as root to 777 and it works. owner / group is 'bin' and 'terminal'. Have tried changing owner to root and that does not stay either. Any ideas on how to keep this port at full permissions?
# 2  
Old 07-14-2005
Dont really know anything about SCO or the usage of serial ports; but if you want the 777 perms to kick in after rebooting, why not put the 'chmod 777 /dev/tty2a' command in a startup script?
# 3  
Old 07-14-2005
That would probably work but doesn't really explain why the permissions are lost. Have been working on this for a while and it is intermittent. It always happens after a reboot but sometimes it is in the middle of the day when there was no reboot.
# 4  
Old 07-14-2005
Permission of serial ports are given by drivers of serial ports.

During reboot , the serial port driver is initialised. in this process, it assignes some default permission for the devices, it controls. Smilie

No idea -- about why permission are lost without reboot. Smilie
# 5  
Old 07-14-2005
Typically, some program like getty controls a tty port. It will issue the login prompt and wait for an answer. When it gets one, it spawns login. But the first thing it does is set the permisions for the login process. The getty is usually controlled by /etc/inittab with a respawn entry.
 
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