Bash Scripts

chrtsetup

set up mounts and enter a chroot

chrtsetup configuration file to set up a unionfs of a disk image and a filesystem tree:

#!bin/bash

# only $CHROOT and $MOUNTS are relevant to chrtsetup
ROOT=/home/user/ubuntu_unionfs
IMG=$ROOT/ext3_1GB.dd
IMG_MNT=$ROOT/diskimage
SHARED=$ROOT/shared
FS=$ROOT/chroot
CHROOT=$ROOT/chroot

#from           to                      fstype  mount-options   do-chroot
MOUNTS=`echo -e "\
/dev            $CHROOT/dev             none    bind            false   \n\
$ROOT/shared    $CHROOT/root/shared     none    bind            false   \n\
$IMG            $IMG_MNT                ext3    loop            false   \n\
unionfs         $CHROOT                 unionfs dirs=$IMAGE_MNT=rw:$FS=ro false \n\
none            /proc                   proc    defaults        true    \n\
none            /sys                    sysfs   defaults        true    \n\
none            /dev/pts                devpts  defaults        true    \n\

the script:

#!/bin/bash
PREPARE=; ENTER=; CLEAN=; VERBOSE=; X=; Y=;
RUN="/bin/bash"
CONFIG=
DISPLAY=

function verbose  { [ $VERBOSE ] && echo $@; $@ 1> /dev/null; }
function warn { [ $VERBOSE ] && echo "warn: $1" >&2; }
function error { echo "error: $1" >&2; exit 1; }
function usage {
  [ "$1" ] && error "$1"
  cat <<EOF
Usage: chrtsetup [OPTIONS] [CHRTCONF]
  -v, --verbose            print actions
  -p, --prepare            perform mount sequence only
  -c, --clean              perform umount sequence only
  -e, --enter              enter chroot only
  -x DISPLAY               configures the xsession defined by DISPLAY
                           to allow all connections from localhost 
                           (xhost +localhost) and sets the DISPLAY
                           variable inside the chroot accordingly to
                           support connecting X11 clients from inside the
                           chroot to your X11 server.
  -y DISPLAY               does the same like -x but additionally sets the 
                           window manager name of the xsession to a 
                           non-reparenting window manager (wmname LG3D) to
                           avoid problems with some jdk versions running
                           with awesome wm. (shouldn't interfere with 
                           conventional use-cases :)
  -r, --run=COMMAND        run specified COMMAND after entering the chroot

CHRTCONF is the name of the chroot configuration stored in /etc/chrtsetup/.
If neither -p, -c nor -e is set -pce is assumed.

Examples:
  chrtsetup ubuntu                                      # executed setup defined in /etc/chrtsetup/ubuntu, enter chroot and clean up after
  chrtsetup -c ubuntu                                   # undo mounts performed to setup the chroot
  chrtsetup -pe ubuntu                                  # mount, enter but do not clean up after
  chrtsetup -x localhost:0.0 --run="xterm" ubuntu       # configure the xsession and start xterm inside the chroot
EOF

  exit 2
}

function chrtify { cmd=$1 doChroot=$2
  if [ "$doChroot" == "true" ]; then 
    echo "chroot -- $CHROOT $cmd"
  else
    echo $cmd
  fi
}

function doUmount { from=$1 to=$2 fstype=$3 opts=$4 doChroot=$5
  umount=`chrtify 'umount' $doChroot`
  verbose $umount -t $fstype $to || error "umount failed: $@"
}

function doMount { from=$1 to=$2 fstype=$3 opts=$4 doChroot=$5
  mount=`chrtify 'mount' $doChroot`
  verbose $mount -t $fstype -o $opts $from $to || error "mount failed: $@"
}

function isMounted { from=$1 to=$2 fstype=$3 opts=$4 doChroot=$5
  grepMounts=`chrtify "grep -qF /etc/mtab -e" $doChroot`
  $grepMounts "$from $to $fstype"
} 

function clean {
  echo "$MOUNTS" | tac | while read mnt; do
    isMounted $mnt && doUmount $mnt \
      || warn "$mnt not mounted" >&2
  done
}

function prepare {
  echo "$MOUNTS" | while read mnt; do
    isMounted $mnt || doMount $mnt \
      && warn "$mnt already mounted" >&2
  done
}

function setupX {
    RUN="DISPLAY=$1 $RUN"
    export DISPLAY=$1 
    xhost +localhost
    [ $Y ] && wmname LG3D
}

### main

[ $# -eq 0 ] && usage

eval set -- "`getopt -o vpecr:x:y: --long verbose,prepare,enter,clean,run: -n 'chrtsetup' -- \"$@\"`"
while true ; do
        case "$1" in
                -v|--verbose) VERBOSE=0 ; shift ;;
                -p|--prepare) PREPARE=0 ; shift ;;
                -e|--enter) ENTER=0 ; shift ;;
                -c|--clean) CLEAN=0 ; shift ;;
                -r|--run) RUN="$2" ; shift 2;;
                -x|--x) X=0; DISPLAY="$2" ; shift 2;;
                -y|--y) Y=0; DISPLAY="$2" ; shift 2;;
                --) shift ; break ;;
        esac
done
CONFIG=$1

[ -z $CONFIG ] && usage "CONFIG is mandatory"
[ ! "$CLEAN" -a ! "$PREPARE" -a  ! "$ENTER" ] && CLEAN=set PREPARE=set ENTER=set

source "/etc/chrtsetup/$CONFIG"
[ "$X" -o "$Y" ] && setupX $DISPLAY
[ $PREPARE ] && prepare
[ $ENTER ]  && chroot "$CHROOT" bash -c "$RUN"
[ $CLEAN ]  && clean

gstrtpcast

Grab audio from a pulse monitor src and stream it via rtp. though pulseaudio is capable of streaming sound via rtp it is not able to compress the stream. additionally its command line tools are crap and its not nearly as flexible as gstreamer. You need to load the module for the alsa dummy device (snd_dummy) before running the script.

#!/bin/bash
ENCODER=" vorbisenc ! rtpvorbispay ";
DEVICE="/dev/video0"
GST_OPTS=
SET_SINK=
CLIENTS=
VERBOSE=

TEMP=`getopt -o e:d:g:vs --long encoder:,device:,gst-opts:,verbose,set-default-sink \
     -n 'gstrtpcast' -- "$@"`

[ $? != 0 ] && exit 1

eval set -- "$TEMP"

while true ; do
	case "$1" in
		-e|--encoder) ENCODER="$2" ; shift 2 ;;
                -d|--device) SRC_NAME="$2" ; shift 2 ;;
		-g|--gst-opts) GST_OPTS="$GST_OPTS $2" ; shift 2 ;;
		-v|--verbose) VERBOSE=0 ; shift ;;
		-s|--set-default-sink) SET_SINK=0; shift ;;
		--) shift ; break ;;
		*) echo "Internal error!" ; exit 1 ;;
	esac
done

CLIENTS="$1"

[ -n $DEVICE ] && DEVICE=`pacmd list-sources | fgrep 'alsa_output.platform-snd_dummy' | awk -F '[<>]' '{ print $2 }'`
[ $SET_SINK ] && pacmd "set-default-sink $[ `echo $SRC_NAME | awk -F '.' '{ print $3 }'` + 1 ]" 1> /dev/null;

echo -e "---\n"
echo "cast: $DEVICE";
echo "to: $CLIENTS";
echo "encoder: $ENCODER"
echo -e "\n---\n"

[ $VERBOSE ] && GST_OPTS="$GST_OPTS -v" echo "gst-launch $GST_OPT pulsesrc device=\"$DEVICE\" ! $ENCODER ! multiudpsink clients=\"$CLIENTS\""

gst-launch $GST_OPTS pulsesrc device="$DEVICE" ! $ENCODER ! multiudpsink clients="$CLIENTS";