- Introduction
- Requirements
- Running
- Upgrading Linux
- Testing SNMP
- Dropbear SSH
- Using Telnet
- Bugs & Feature Requests
TroglOS is a playful, but working, example of how to create a virtual devboard from the ground up with components like Linux and BusyBox.
Use the build framework in TroglOS to test your embedded applications before the actual hardware arrives. Or as a reference when said hardware starts acting up -- as it invariably does ...
Currently TroglOS targets an ARM Versatile PB devboard with Qemu. GitHub pull requests to support more targets are very welcome!
The build environment requires at least the following tools, tested on Ubuntu 14.04, 15.04, and 15.10:
- gcc-arm-linux-gnueabi
- cpp-arm-linux-gnueabi
- binutils-arm-linux-gnueabi
- libc6-armel-cross
- libc6-dev-armel-cross
- curl
- make
- gcc (or clang, for the menuconfig interface)
- quilt
- qemu-system-arm
- (install libvirt-bin and virt-manager as well!)
- probably more, gzip?, mkimge?
TroglOS uses Qemu to run the resulting kernel + image. For networking you may need to do the following to your host system, here Ubuntu 14.04:
sudo chmod 4755 /usr/lib/qemu-bridge-helper
sudo dpkg-statoverride --add root root 4755 /usr/lib/qemu-bridge-helper
In Ubuntu 15.04 the helper script has moved to a qemu sub-directory:
sudo chmod 4755 /usr/lib/qemu/qemu-bridge-helper
sudo dpkg-statoverride --add root root 4755 /usr/lib/qemu/qemu-bridge-helper
The first command makes the Qemu helper "suid root", which means we're allowed to manipulate the network to gain external network access. The last command is for Debian/Ubuntu system, it makes sure to record your change so that any Qemu package upgrades will overwrite our mode change.
Now you need to tell Qemu what bridges in the system you are allowed to
connect to, edit/create the file /etc/qemu/bridge.conf and add:
allow virbr0
Assuming you have a virbr0 interface in your system. If you've run
anything in virt-manager prior to this then
you're set, otherwise you're unfortunately on your own.
Clone this repository, then type make. When the build has completed,
start Qemu with make run -- Have fun!
Change the KERNEL_VERSION in the top-level Makefile. If the kernel
is just a minor patch release, you're done.
If it's a major kernel upgrade, copy the latest kernel/config-X.YY to
kernel/config-X.ZZ and call make kernel_oldconfig. This will unpack
the kernel and give you a set of questions for all new features.
Make sure to do a make kernel_saveconfig, and possibly add the new
kernel/config-X.ZZ to GIT.
TroglOS uses Robert Ernst's mini_snmpd as its SNMP daemon currently. It's extremely small and therefore very limited in its functionality, but it's enough to monitor TroglOS by remote if needed.
To test it you need an SNMP client. The following command installs
snmpset, snmpget, snmpwalk, base MIBs and all standard MIBs
needed. You may also be interested in a more graphical alternative,
snmpB
$ sudo apt-get install snmp libsnmp-base snmp-mibs-downloader
When done you should be able to do the following:
$ snmpwalk -v2c -c public 192.0.2.42
SNMPv2-MIB::sysDescr.0 = STRING: TroglOS Linux Virtual Devboard
SNMPv2-MIB::sysObjectID.0 = OID: SNMPv2-SMI::enterprises
SNMPv2-MIB::sysUpTime.0 = Timeticks: (465) 0:00:04.65
SNMPv2-MIB::sysContact.0 = STRING: troglobit@gmail.com
SNMPv2-MIB::sysName.0 = STRING: chaos
SNMPv2-MIB::sysLocation.0 = STRING: GitHub
IF-MIB::ifNumber.0 = INTEGER: 1
IF-MIB::ifIndex.1 = INTEGER: 1
IF-MIB::ifDescr.1 = STRING: eth0
IF-MIB::ifOperStatus.1 = INTEGER: up(1)
IF-MIB::ifInOctets.1 = Counter32: 5557
IF-MIB::ifInUcastPkts.1 = Counter32: 45
IF-MIB::ifInDiscards.1 = Counter32: 0
IF-MIB::ifInErrors.1 = Counter32: 0
IF-MIB::ifOutOctets.1 = Counter32: 2958
IF-MIB::ifOutUcastPkts.1 = Counter32: 19
IF-MIB::ifOutDiscards.1 = Counter32: 0
IF-MIB::ifOutErrors.1 = Counter32: 0
SNMPv2-SMI::mib-2.25.1.1.0 = Timeticks: (71983) 0:11:59.83
$ snmpget -c public -v 2c 192.0.2.42 system.sysUpTime.0
SNMPv2-MIB::sysUpTime.0 = Timeticks: (2344) 0:00:23.44
The most common embedded SSH daemon in use on embedded Linux systems today is Dropbear by the incredibly humble Matt Johnston.
Dropbear is started by default in TroglOS. It currently allows root
access, but we recommend disabling this and instead setting up another
user: adduser example
Test SSH from your host simply by: ssh example@192.0.2.42
Currently telnetd is started by default in TroglOS, this will change
in the future, but it will still be available.
Test it from your host by simply calling telnet 192.0.2.42
Feel free to report bugs and request features, or even submit your own pull requests using GitHub
Cheers!
-- Joachim