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This page describes how to compile dropbear to run in Technologic System's TS-Linux for ARM distribution. Debian was used for development and cross compiling. The TS-7260's root file system uses the RedBoot NFS option.


crosstool setup

download and setup ts crosstool package

  • At the time of this writing, the Linux Crosstool gcc-4.0.1-glibc-2.3.5 -- unknown (05-20-2006) was available

move it to / and unpack it

$ cd /
$ sudo tar -xf crosstool-linux-gcc-4.0.1-glibc-2.3.5.tar

add it to your path

$ cat ~/.bash_profile | grep cross
PATH=/opt/crosstool/gcc-4.0.1- glibc-2.3.5/arm-unknown-linux-gnu/bin:${PATH}


download dropbear

$ wget http://matt.ucc.asn.au/dropbear/releases/dropbear-0.49.tar.bz2
$ cd dropbear-0.49/


  • dropbear needs access to a good random pool in /dev/random and for some reason it would always hang on /dev/random and would print this message while running:
Warning: Reading the random source seems to have blocked.
If you experience problems, you probably need to find a better entropy source. 
  • so i edited options.h and changed the random device to be urandom for this error.
#define DROPBEAR_RANDOM_DEV "/dev/urandom"
  • the shell script i used to automate the build process
$ cat run.sh 
export CFLAGS="-Os -static -Wall"
export LDFLAGS="-static"
./configure --host=arm-unknown-linux-gnu --build=arm --disable-zlib --disable-syslog --disable-lastlog (optionally add --enable-static)
make clean
make PROGRAMS="dropbear dbclient dropbearkey dropbearconvert scp" MULTI=1 STATIC=1

move files

  • relocate files to nfs directory
$ ln -s dropbearmulti ssh
$ mv dropbear ssh scp dropbearmulti dropbearkey dropbearconvert ../tslinux/usr/sbin/
$ mv dbclient ../tslinux/usr/bin


disable ssh for inetd

$ cat etc/inetd.conf | grep ssh
#ssh    stream  tcp     nowait  root    /usr/sbin/dropbear      dropbear -i
$ kill -HUP <pid of inetd>

create init.d script

$ cat etc/init.d/dropbear  
OPTIONS="> /dev/null 2>&1"

case "$1" in
       echo "Starting dropbear..."
       /usr/sbin/dropbear $OPTIONS
        echo "Stopping dropbear..."
        pid=`pidof dropbear`
        if [ "$pid" != "" ]; then
           kill $pid
        $0 stop 
        $0 start
       echo "usage: start|stop|restart"

create rc link

$ cd etc/rc.d/rc3.d/
$ ln -s ../../init.d/dropbear S99dropbear

fix dropbear errors by recreating links

ssh to ts-board and make create a bash script like this one:

  • Note: TS-7260 uses sh, so use: #!/bin/sh instead of #!/bin/bash
# Remove All /usr/sbin
rm -rf /usr/sbin/scp
rm -rf /usr/sbin/ssh
rm -rf /usr/sbin/dbclient
rm -rf /usr/sbin/dropbear
rm -rf /usr/sbin/dropbearkey
rm -rf /usr/sbin/dropbearconvert
# Remove All /usr/bin
rm -rf /usr/bin/scp
rm -rf /usr/bin/ssh
rm -rf /usr/bin/dbclient
rm -rf /usr/bin/dropbear
rm -rf /usr/bin/dropbearkey
rm -rf /usr/bin/dropbearconvert
# Link All /usr/sbin
ln -s /usr/sbin/dropbearmulti /usr/sbin/scp
ln -s /usr/sbin/dropbearmulti /usr/sbin/ssh
ln -s /usr/sbin/dropbearmulti /usr/sbin/dbclient
ln -s /usr/sbin/dropbearmulti /usr/sbin/dropbear
ln -s /usr/sbin/dropbearmulti /usr/sbin/dropbearkey
ln -s /usr/sbin/dropbearmulti /usr/sbin/dropbearconvert
# Link All /usr/bin
ln -s /usr/sbin/dropbearmulti /usr/bin/scp
ln -s /usr/sbin/dropbearmulti /usr/bin/ssh
ln -s /usr/sbin/dropbearmulti /usr/bin/dbclient
ln -s /usr/sbin/dropbearmulti /usr/bin/dropbear
ln -s /usr/sbin/dropbearmulti /usr/bin/dropbearkey
ln -s /usr/sbin/dropbearmulti /usr/bin/dropbearconvert