I'm working on Linux Kernel 3.14.28 build with Buildroot for an embedded device.
In /dev/
, all ttys are root:root
and not root:dialout
like a standard Linux. So it is not possible to access any ttyX without being logged as root
.
How can I change the tty group permanently to root:dialout
? I try to change it with chown command, but it became root:root
again on reboot.
devtmpfs
always sets permissions to0600
and makes it up toudev
(or whatever runs after it) to maintain them. Its source confirms there's no way to override this explicitly (tty
device driver overridesmode
unconditionally in some cases).Assuming you're using the Buildroot's default
busybox
asinit
, there's a way to do this with the following additional line inbusybox
'sinittab
(additional=must be present in addition to the essential lines (or their replacements) that are implied when there's noinittab
- as they are no longer implied then there is):with the script calling
chown
andchmod
in loop.But, it's better to handle this within the existing
/etc/init.d/rcS
(which is also run by BusyBox'sinit
atsysinit
by default).As you can see from the stock buildroot's
/etc/init.d/rcS
, all you need to do is create a script/etc/init.d/S<whatever>.sh
(where "whatever" places it into the desired position in the/etc/init.d/S??*
output) with your commands: