aports/testing/lxc/setup-lxc-guest

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#!/bin/sh
# simple script to set up a new lxc guest
# test the first argument against the remaining ones, return success on a match
isin() {
local _a=$1 _b
shift
for _b; do
[ "$_a" = "$_b" ] && return 0
done
return 1
}
# remove all occurrences of first argument from list formed by
# the remaining arguments
rmel() {
local _a=$1 _b
shift
for _b; do
[ "$_a" != "$_b" ] && echo -n "$_b "
done
}
# Issue a read into the global variable $resp.
_ask() {
local _redo=0
read resp
case "$resp" in
!) echo "Type 'exit' to return to setup."
sh
_redo=1
;;
!*) eval "${resp#?}"
_redo=1
;;
esac
return $_redo
}
# Ask for user input.
#
# $1 = the question to ask the user
# $2 = the default answer
#
# Save the user input (or the default) in $resp.
#
# Allow the user to escape to shells ('!') or execute commands
# ('!foo') before entering the input.
ask() {
local _question=$1 _default=$2
while :; do
echo -n "$_question "
[ -z "$_default" ] || echo -n "[$_default] "
_ask && : ${resp:=$_default} && break
done
}
# Ask for user input until a non-empty reply is entered.
#
# $1 = the question to ask the user
# $2 = the default answer
#
# Save the user input (or the default) in $resp.
ask_until() {
resp=
while [ -z "$resp" ] ; do
ask "$1" "$2"
done
}
# Ask for the user to select one value from a list, or 'done'.
#
# $1 = name of the list items (disk, cd, etc.)
# $2 = question to ask
# $3 = list of valid choices
# $4 = default choice, if it is not specified use the first item in $3
#
# N.B.! $3 and $4 will be "expanded" using eval, so be sure to escape them
# if they contain spooky stuff
#
# At exit $resp holds selected item, or 'done'
ask_which() {
local _name=$1 _query=$2 _list=$3 _def=$4 _dynlist _dyndef
while :; do
# Put both lines in ask prompt, rather than use a
# separate 'echo' to ensure the entire question is
# re-ask'ed after a '!' or '!foo' shell escape.
eval "_dynlist=\"$_list\""
eval "_dyndef=\"$_def\""
# Clean away whitespace and determine the default
set -o noglob
set -- $_dyndef; _dyndef="$1"
set -- $_dynlist; _dynlist="$*"
set +o noglob
[ $# -lt 1 ] && resp=done && return
: ${_dyndef:=$1}
echo "Available ${_name}s are: $_dynlist."
echo -n "Which one $_query? (or 'done') "
[ -n "$_dyndef" ] && echo -n "[$_dyndef] "
_ask || continue
[ -z "$resp" ] && resp="$_dyndef"
# Quote $resp to prevent user from confusing isin() by
# entering something like 'a a'.
isin "$resp" $_dynlist done && break
echo "'$resp' is not a valid choice."
done
}
# Ask for user input until a non-empty reply is entered.
#
# $1 = the question to ask the user
# $2 = the default answer
#
# Save the user input (or the default) in $resp.
ask_until() {
resp=
while [ -z "$resp" ] ; do
ask "$1" "$2"
done
}
# http://en.wikipedia.org/wiki/Hostname#Restrictions_on_valid_host_names
valid_hostname() {
# check length
if [ $(echo "$1" | wc -c) -gt 63 ]; then
echo "Hostname '$1' is too long."
return 1
fi
# check that it only contains valid chars
if ! [ -z "$(echo $1 | sed 's/[0-9a-z-]//g')" ]; then
echo "Hostname must only contain letters (a-z), digits (0-9) or -"
return 1
fi
# must not start with -
case "$1" in
-*) echo "Hostname must not start with a '-'"; return 1;;
esac
return 0
}
# return last ipv4 address and mask
#
# $1 = interface
#
last_ipv4_addr_mask() {
local _iface=$1
ip addr show dev $_iface | awk '$1 == "inet" {print $2}' | tail -n1
}
valid_ip_and_prefix() {
[ "$1" ] || return 0
ipcalc -s -m $1 >/dev/null 2>&1 && ! ipcalc -s -m $1/0 >/dev/null 2>&1
}
# ask for hostname
#
# $1 = default
#
# retrusn hostname in global var $resp
#
ask_hostname() {
while true; do
ask "Hostname for new lxc container:" $1
if [ -d /var/lib/lxc/$resp ]; then
echo "/var/lib/lxc/$resp already exist"
continue
fi
if [ -d /lxc/$resp ]; then
echo "/lxc/$resp already exist"
continue
fi
valid_hostname $resp && break
done
}
ask_ifaceopts() {
# get ip address(es)
resp=
local ifaceopts= _def= _iface=
local ifaces=$(ip addr | awk -F: '$1 ~ /^[0-9]/ {printf "%s" $2} END {printf "\n"}')
local last_iface=$(echo $ifaces | sed 's/.* //')
while [ "$resp" != "done" ]; do
if [ -z "$ifaces" ] || [ "$ifaces" = "lo " ] || [ -n "$ifaceopts" ]; then
_def="done"
else
_def=$(echo $ifaces | sed 's/.* //')
fi
ask_which "network interface" "to use for $_hostname" \
"$ifaces" $_def
[ "$resp" = "done" ] && break
_iface=$resp
ifaces=$(rmel $_iface $ifaces)
# suggested ip by last digit + 1
_last_ip_mask=$(last_ipv4_addr_mask $_iface)
_last_ip=${_last_ip_mask%/*}
_last_ip_digit=${_last_ip##*.}
_ip=${_last_ip%.*}.$((($_last_ip_digit + 1) % 256))
_mask=${_last_ip_mask#*/}
while true; do
ask "Enter IP address/mask for $_iface:" $_ip/$_mask
valid_ip_and_prefix "$resp" 2>&1 && break
echo "$resp is not a valid IPv4 address/mask"
done
_ip_mask=$resp
ifaceopts="$ifaceopts --interface $_iface:$_ip_mask"
echo "lxc.network.ipv4 = $_iface/$_ip_mask" >> /tmp/lxc-$hostname.conf
conffile=/tmp/lxc-$hostname.conf
done
resp="$conffile"
}
ask_template() {
local temp
# get template
while true; do
ask "Enter template file (or empty for generate a new):" \
$_template
if [ -z "$resp" ] || [ -r "$resp" ]; then
break
fi
echo "Can not read $resp"
done
temp=$resp
if [ -z "$temp" ]; then
temp=/tmp/template.tar.gz
echo "Generating template..."
if setup-lxc-template -q -o $temp; then
echo "ok"
else
echo "Failed to create template"
exit 1
fi
fi
resp=$temp
}
usage() {
echo "Usage: ${0##*/} [-h] [HOSTNAME...]"
exit 1
}
while getopts "h" opt; do
case "$opt" in
h) usage;;
?) usage;;
esac
done
shift $(($OPTIND - 1))
if [ "$(whoami)" != "root" ]; then
echo "Need to be root. Sorry."
exit 1
fi
while true; do
ask_hostname $1
_hostname=$resp
ask_ifaceopts
_conffile=$resp
ask_template
_template=$resp
lxc-create -n $_hostname \
-f $_conffile \
-t "$_template" \
|| exit 1
shift
[ $# -le 0 ] && exit 0
done