GUF-Yocto-jethro-9.0-r7707-0
i.MX6
User Manual
Note:
Due to the fact that telnet does not use encryption, it is recommended to deactivate this service
in final products in order to avoid security leaks. Disabling services is described in the chapter
[
I
.
The telnet service has a startup link that points to the corresponding start script:
/etc/rc.d/S20telnet -> /etc/init.d/telnet
The startup script simply starts
/usr/sbin/telnetd
as a daemon. The usage of telnetd is shown by executing:
root@santaro:~# telnetd --help
BusyBox v1.22.1 (2015-09-17 20:08:55 CEST) multi-call binary.
Usage: telnetd [OPTIONS]
Following options are available and configured directly in the start script
/etc/init.d/telnet
:
Options:
-l LOGIN
Exec LOGIN on connect
-f ISSUE_FILE
Display ISSUE_FILE instead of /etc/issue
-K
Close connection as soon as login exits
(normally wait until all programs close slave pty)
-p PORT
Port to listen on
-b ADDR[:PORT]
Address to bind to
-F
Run in foreground
-i
Inetd mode
-w SEC
Inetd 'wait' mode, linger time SEC
-S
Log to syslog (implied by -i or without -F and -w)
4.1.5 Module loading
The
modules
service is responsible for external module loading at system startup. It has a startup link that points
to the corresponding start script:
/etc/rcS.d/S05modutils.sh -> /etc/init.d/modutils.sh
The startup script simply looks which modules are listed in
/etc/modules
and loads them using
/sbin/modprobe
.
To ensure that the module loading works correctly, the module dependencies in
/lib/modules/<kernel ver-
sion>/modules.dep
have to be consistent.
4.1.6 Network initialization
The
network initialization
service is responsible for initializing all network interfaces at system startup. Garz &
Fricke systems use ifplugd to detect if an ethernet cable or an WLAN stick is plugged.
The network interfaces (including WLAN) are listed on the target system in the configuration file
/etc/network/in-
terfaces
. On conventional Linux systems, the user configures the network interfaces by hand using this file.
On Garz & Fricke systems, there is a service called
sharedconf
as described in
[
I
that generates this file automatically according to the settings in the global XML configuration.
If the user wants to change the network settings (including WLAN and its AP setup), it is recommended to use
the
sconfig
script as described in
[
I
4.2.1 Garz & Fricke system configuration]
.
Note:
Changes that are made to
/etc/network/interfaces
and
/etc/wpa_supplicant.conf
directly will
be overwritten by the sharedconf service on the next system startup and have no effect.
4.1.7 Watchdog
Generally a watchdog is a subsystem that monitors the system state in some way and executes a reset when a
malfunction is detected.
The watchdog service is built of a hardware watchdog device and a linux service.
18
